UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING · UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 1...
Transcript of UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING · UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 1...
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 1
CHAPTER 1
INTRODUCTION
1.1 Background of the Study
Brine evaporation is the process of vaporizing the liquid in seawater in
order to produce a crystalline solid (Korovessis and Lekkas, 2009). This may be
induced either by using heat or through solar energy (Akridge, 2008). Table
salt is largely manufactured in solar salt ponds wherein seawater at 3.5%
salinity (w/v), undergoes a series of evaporator ponds where much of the
water it contained is removed naturally, yielding salt that is a primary necessity
of mankind (Oren, 2010). In solar salt ponds, a green microalgae was
discovered to survive in more saline solutions (Oren, 2011). This microalgae,
Dunaliella sp. changed the physical characteristics of the brine in ponds
changing its color to green (Mendoza et al., 2008). It was also discovered later
on that these Dunaliella species are a great source of beta-carotene, an
essential nutrient which promotes good eyesight, and glycerol, which can be
further converted into a source of energy as biodiesel (Ralefala, 2011).
Since it was observed that it had no significant impact to the quality of
salt produced, many salt manufacturers or salterns have cultivated this culture
into their ponds in lieu of other possibilities. However, most salterns with
these types of species occurring in their ponds have devised a way to improve
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 2
the evaporation rate of brine. This is through the use of benthonic
communities that are not invasive in the salt production process but can create
a harmonious food cycle with Dunaliella (Butinar et al., 2005).
So far, this innovation on increasing the evaporation rate using the
microalgae has not been introduced by salt manufacturers in the Philippines.
Other salterns in the United States and other countries have utilized different
types of Dunaliella strains that are capable of changing colors from green to
pink (Creswell, 2010). Through thorough studies on Dunaliella strains applied
in the Philippine environment, new opportunities for improving the salt
production and quality may arise.
1.2 Statement of the Problem
Relevant studies have proven that the incorporation of Dunaliella
tertiolecta culture improves the process of evaporation and the amount of
brine evaporated (Tafreshi and Shariati, 2008). Without sufficient knowledge
of the culture, propagation, and optimum environment it can survive with,
such innovative application could not be utilized to its fullest capacity. The
concern now is to quantify its impact to brine evaporation and arrive at the
optimum amounts of controllable factors necessary to achieve faster brine
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 3
evaporation and effective replenishment of the algae for other possible
applications.
1.3 Significance of the Study
Despite of the Philippines being an archipelagic country with plenty of
resources for salt manufacturing, its needs for industrial and household salt
could not be accommodated by domestic salt-making farms and companies.
This study intends to fill the information gap on brine evaporation with
Dunaliella tertiolecta cultures in order to produce higher yields of table salt
that would benefit Filipino consumers and businesses by minimizing
importation of salt from larger salt-producing countries. This study also
provides an alternative in the mass production of Dunaliella tertiolecta culture
that minimizes the risk of algal death due to crowding and overpopulation.
This would help lessen the waste of valuable resource and would allow salt
manufacturers to effectively utilize the said technology. The findings of this
study would be profitable to this study’s benefactor, Salinas Foods
Incorporated, as it allows the development of better techniques for brine
evaporation and utilization of algae for viable biodiesel applications.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 4
1.4 Objectives
The main objectives of this thesis are to quantify the impact of
Dunaliella tertiolecta to the evaporation rate of brine and identify the optimal
conditions required for high evaporation and culture sustainability. In line with
this, the study also intends to accomplish the following specific objectives:
To determine the relationship of adjustable factors such as brine depth,
brine salinity and brine turbidity to the evaporation rate of brine.
To quantify how much the evaporation rate of brine would increase when
Dunaliella tertiolecta is incorporated in brine.
To identify the optimum parameters that would both yield the highest
evaporation rate of brine with Dunaliella tertiolecta and assure algal
biomass survivability.
1.5 Assumptions
A higher evaporation rate of brine can be produced when brine is
incorporated with the green microalgae, Dunaliella tertiolecta.
1.6 Scope and Limitations
The study deals with the quantification and optimization of the
evaporation rate of brine incorporated with Dunaliella tertiolecta through
solar evaporation. In the process of achieving this goal, the evaporation rate
of Dunaliella tertiolecta cultures with and without dilution will be studied. It
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 5
will also include behavior of turbidity with dilution and a chart from the results
will be utilized to determine succeeding turbidities. The study will also see the
effect of adding a layer of soil in the simulation ponds. This study therefore
would only be focusing on controllable factors namely brine depth, brine
salinity and brine turbidity. The effect of other environmental factors like
temperature, humidity, solar radiation, and wind speed on the evaporation
rate of brine are considered but not expounded upon.
1.7 Definition of Terms
• Algae
Single-celled plants that can range from microscopic to large. They have
chlorophyll and can manufacture food through photosynthesis.
Benthonic
A collection of organisms living on or in the body of water.
Brine
A heterogeneous mixture of salt and water.
Dunaliella species
A green microalgae that proliferate in salt ponds.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 6
Evaporation
The process at which water in solution and liquid form is vaporized into
gaseous state.
Flocculation
The phenomenon at which suspended particles and colloids aggregate or form
together into lumps or floc.
Salinity
The measure of all dissolved salts in water. Can be measured in degree
Baumé (°Bé) or % NaCl (w/v)
Saltern
An area or place used for salt making.
Turbidity
The measure of relative clarity of a liquid. It is an optical characteristic of water
and is an expression of the amount of light that is scattered by material in the
water when a light is shined through the water sample.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 7
CHAPTER 2
REVIEW OF RELATED LITERATURE
This chapter states the diverse literature and reported studies regarding
the research topic. This include an overview on salt ponds and salt production;
evaporation methods; factors affecting evaporation; physiology and culture of
Dunaliella tertiolecta; and climatic effects to evaporation of brine.
2.1 Salt ponds
The extensive use of sodium chloride as raw material in the chemical
industry have increased salt consumption worldwide, with annual figures reaching
200 million tons nowadays. One third of this is produced in solar saltworks
(Korevessis and Lekkas, 2009).
Along tropical and subtropical coasts worldwide, saltern systems are found
in which seawater is evaporated for the commercial production of common salt
(NaCl) and sometimes other salts as well. To obtain salt of high purity, such
salterns are designed to consist of a series of shallow ponds in which the seawater
is evaporated in stages, keeping the salinity of each pond within a narrow
range. Calcium carbonate (calcite, aragonite) and calcium sulfate (gypsum)
precipitate in the early stages of evaporation. Then sodium chloride (halite)
precipitates in crystallizer ponds with total dissolved salt concentration at
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 8
approximately 300 to 350 g/L. The remaining brines that contain high
concentrations of magnesium, potassium, chloride and sulfate are generally
returned to the sea (Oren, 2009).
Solar salterns contain rich and varied communities of phototrophic
microorganisms along the saltern gradient, and the photosynthetic primary
production by these communities largely determines the properties of the
saltern system. The study of phototrophic autotrophs that inhabit salterns is not
only of purely scientific interest: the benthic cyanobacterial mats that develop in
saltern ponds of intermediate salinity effectively seal the bottom of these ponds
and prevent leakage of brine; on the other hand, unicellular cyanobacteria in these
mats and in the brine itself sometimes produce massive amounts of
polysaccharide slime that unfavorably affects the salt production process (Oren
2009).
2.2 Processes of salt production
Modern solar saltworks consist of a system of shallow ponds (15-60 cm
deep) mainly connected in series. Their bottoms are natural and have the
appropriate clay composition that ensure low water permeability. Their operation
principle is basically concerned with the means by which brine is transferred and
salt is harvested, resulting from subsequent technological progress. (Korevessis &
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 9
Lekkas, 2009) Figure 2.1 shows the typical process flow of manufacturing salt and
it shows how salt is made from sea water.
Figure 2.1 Process Flow in Salt Making
On a global scale, a solar saltern is not a major ecosystem that contributes
to primary biological production. However, the highly diverse biological system of
salterns with evaporation and crystallizer ponds of different salinities, and often
with high densities of planktonic as well as benthic phototrophic microorganisms
makes salterns excellent model systems for the study of primary production under
a variety of conditions (Oren, 2009).
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 10
2.3 Physicochemical process of salt production
Physicochemical process of salt production is actually the process that
current solar salterns use to recover salt from seawater, although there have been
improvements and variations allowing for the production of some hundred to
some million tons of salt depending on the size of the area in use. According to
this process, the ponds are divided into two basic groups. The first group is called
evaporating ponds which is where seawater is concentrated up to saturation point
in terms of NaCl concentration. The bottom is natural without any intervention
and the concentration of contained brine covers the whole range from 3.8 °Be
(almost seawater) to 25.7°Be, corresponding to the last pond which feeds the
crystallizers continuously with the required saturated brine (nurse pond). They
cover almost 90% of the saltern production area since 90% of the water in
seawater to be concentrated up to the point of salt crystallization.
The second group is called crystallizers or pans. It consists of the ponds
where salt crystallizes via further evaporation of the brine up to 28-29 °Bé.
Crystallizers take up the remaining 10% of the production area. These ponds are
specially designed and have their bottom level concentrated aiming to facilitate
and optimize mechanical salt harvesting. A salinity vector is created throughout
the ponds of the saltern with simultaneous and continuous reduction of the
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 11
volume of seawater which initially entered the pond system (Korevessis and
Lekkas, 2009).
2.4 Biological process of solar salt production process
Despite rising salinity, life in the salt ponds do not stop. Seawater
organisms gradually disappear as they move from the hostile environment of
other organisms. Without the presence of these predators, these organisms
proliferate. Large populations are able to survive in areas with different
concentration levels because of their varying sensitivity to the ion composition of
the medium they inhabit.
Parallel with the physicochemical process, a chain of organisms is
developed in the evaporating ponds system, similar to those of naturally saline
or hyper saline coastal ecosystems, constituting the biological process of solar
salt production process. This process depends on the quality of seawater feed,
the prevailing conditions in the ponds such as brine temperature, depth, turbidity
and concentration, and the control of the physicochemical process during salt
production and the overall design of the salt works (Korevessis and Lekkas, 2009).
On the work of Korovessis and Lekkas (2008) about improving microbial
growth, the cultures were divided and distributed to other ponds to multiply.
Mother cultures were subdivided into two then these are subdivided it into four
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 12
cultures, to the point that the desired amount of cultures is achieved. Figure 2.2
shows the different stages of brine concentration.
Figure 2.2 Stages in Brine Concentration for Salt Production
2.5 Evaporation
Evaporation is the process at which a medium accumulates sufficient
latent and sensible energies that result to phase transformation from liquid to gas
(Naschon et al., 2011). Evaporation is the process by which water is converted
from its liquid form to its vapor form. This is how water is transferred from land
and water masses to the atmosphere. Evaporation from the ocean accounts for
80% of the water delivered as precipitation with the balance occurring on land,
inland waters, and plant surfaces. It plays a critical role in salt production and is
greatly affected by both of its intrinsic and extrinsic factors (Lensky et al., 2005).
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 13
2.6 Methods of Evaporation of brine solution
Salt production has often been described as a labor intensive endeavor
requiring and time consuming task (Sundaresan, Ponnuchammy, and Rahaman,
2006). The procedures used in making salt varied by geographic region and
resources locally available. The quantity desired by the local population may have
also influenced the choice of salt production methods (Akridge, 2008).
Numerous studies have focused on the techniques and archaeological
remnants of saltworks. Three distinct techniques for evaporating brine are
described. Solar evaporation, evaporation from boiling due to an externally
applied heat source and evaporation from boiling caused by hot immersed object
these techniques were used sometimes in combination, to achieve the desired
evaporation (Akridge, 2008).
2.6.1 Solar Evaporation
In salt production, a vessel or ponded area containing brine is
allowed to evaporate under prevailing environmental conditions. This
technique works best at low latitudes where sunlight duration and
intensity are highest and areas with low relative humidity and rainfall.
Solar evaporation becomes the default method when fuel resources are
scarce and boiling of brine is unfeasible. Historically, this technique was
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 14
common in coastal areas and continues to be a viable commercial process
worldwide. Solar evaporation could have been practiced at many inland
salines where brine concentrations tend to be high thus reducing total
evaporation time (Akridge, 2008). Solar evaporation of sea water to
produce brine is not only a physical process but also entail the organic
contribution of biological communities within the pond ecosystem
(Sundaresan et al., 2006).
2.6.2 Evaporation from an externally heated pan
This technique typically involves the suspension of a vessel over a
fire or emplacement of a vessel directly onto a bed of hot coals. Heat is
transferred through the base and walls of the vessel and warms the
interior fluid. The amount of heat transferred to the brine is governed by
the energy output of the fire and efficiency of heat transfer in a particular
brine boiling set-up (Akridge, 2008).
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 15
2.6.3 Evaporation using hot immersed objects
This evaporation scenario considers a hot object (e.g. stone) placed
inside a pan of brine. This method is believed to have been utilized for salt
production in eastern North America from about A.D. 1000-1400. Stone
boiling as a cooking technique probably began with the introduction of
pottery (Akridge, 2008).
2.7 Parameters that Affect the Evaporation of Brine
Natural brine is a commercially important source of industrial salt and
occurs underground, in salt lakes, or as seawater. There are several factors
affecting brine evaporation. Some of these factors are due to the location of the
system. The system may be placed on a location that is ecologically rich in different
species of living things interrelating with each other to form an environment. Even
in the system, microorganisms which give coloration to the brine can affect the
evaporation rate. Another factor is the climatic condition where summer yields
the highest evaporation rate of brine. Brine concentration is another factor where
the higher the concentration, the longer it takes to evaporate brine.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 16
2.7.1 Salinity on the Evaporation of Brine
Salinity is the measure of all dissolvable salts in water quantified in
grams per liter of total dissolved solids (TDS) or in other measurements
such as degree Baumé (°Bé) which is based on the specific gravity of brine.
Salt is produced by solar evaporation and methods for concentrating brine,
salt solutions of around 3.5 g/L and above, have been established
throughout the years.
On a basis at which brine solution is evaporated and concentrated
to crystallization, salinity showed adverse effects on the evaporation rate
of water. Based on a study on hydrological bases as seen in Figure 2.3, the
evaporation factor as well the evaporation rate of water decreases
exponentially as the salinity increases (Leaney and Christen, 2000).
The second law of thermodynamics implies that an increase in ion
activity as a result of the presence of solute reduces the chemical potential
of a liquid solvent and also the rate of spontaneous transformation of the
liquid phase into the vapor phase (Kokya & Kokya, 2006).
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 17
Figure 2.3 Effect of salinity in the evaporation factor, F.
The reduction in evaporation rate for salinity levels, S (g/L) up to
320 g/L has been approximated using the following relationship where F is
the evaporation factor (Leaney and Christen, 2000):
F = 1.025 − 0.0246 ∙ 𝑒 (0.00879 ∙ S) (1)
This phenomenon may be brought about by the tendency of water
to become ionized with salts, improving its bonding properties and
elevating its boiling temperature. Approaching the solubility limit of salt in
water also impedes evaporation as the vapor-diffusion coefficient is
significantly decreased due to the mechanical clogging of the matrix by
precipitated salt (Naschon et al., 2011).
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 18
Another study showed the variability of evaporation with
increasing salinity. Dama-Fakir and Toerien (2009) included in their work
the results from an observation done by Kokya and Kokya (2006) on
evaporator pans in attempt to propose an evaporation measurement for
saltwater resources.
Table 2.1 Observed evaporation rate with of samples from various sources
containing different counts of Total Dissolved Solids (TDS)
As described in Table 2.1, a decreasing trend in the evaporation
rate may be generalized as the Total Dissolved Solids (TDS) of the system
increases. This combines both organic and inorganic substances contained
in the liquid in molecular, ionized and colloidal state (Sigler and Bauder,
2015).
2.7.2 Microalgae Halophiles on the Evaporation of Brine
Methods of improving the evaporation of saltwater utilized
different microbial communities which did not hinder the output in salt
Day Observed Evaporation (mm)
Fresh Water (TDS= 0.2 g/L)
Ocean Water (TDS= 40 g/L)
Semi-Saline Water
(TDS= 80 g/L)
Salt Water (TDS= 160 g/L)
Urmia Lake Water
(TDS= 350g/L)
1 6.5 6.0 5.2 4.7 3.1
2 7.6 7.1 6.0 5.0 4.0
3 7.2 6.8 5.4 4.1 3.4
4 7.2 6.9 6.0 4.8 3.9
5 6.5 6.1 5.8 5.5 4.4
6 7.5 7.0 6.3 5.2 4.5
7 6.3 5.9 5.1 4.0 3.1
8 8.0 7.4 6.3 5.8 3.2
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 19
production. Figure 2.4 shows examples of microorganism that can
withstand high saline concentration. The halophilic autotrophic
microalgae, Dunaliella tertiolecta, was first sighted in the saltern
evaporation ponds in Southern France and was named by the Romanian
Botanist Emanoil C. Teodoresco from the discoverer Michel Felix Dunal
(Oren, 2011).
Figure 2.4 Halophilic microorganisms that can be found in solar salterns
This unicellular green alga is responsible for most of the primary
production in hypersaline environments (Oren, 2005). Dunaliella
tertiolecta is one of the few species of microalgae which can be mass
cultured outdoors including semi-intensive systems in hypersaline lakes
due to its wide halotolerance range, it allows the culture to change the
color and turbidity of the brine solution it occupies. It has an organic
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 20
weight of 85 picograms per cell (Creswell, 2010), and has a saturation limit
of 8.6x106cells/mL in DeWalne’s medium (Venkatesan et. al. 2013). This
increase in turbidity is a quantifiable factor that offers viability of increased
absorbance of light compared to clear brine. D. tertiolecta synthesizes and
accumulates dark green pigments which elevate the brine’s absorbency of
solar energy (Zhiling and Guangyu, 2006).
Figure 2.5 Growth curve of Dunaliella salina and Dunaliella tertiolecta in
Dewalne’s medium
D. tertiolecta changes depending on external factors like high
salinity, light intensity, pH and nutrient intake (Tafreshi and Shariati, 2008).
Because D. tertiolecta provides coloration to the ponds, relevant
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 21
experimentation shows that cultures of D. tertiolecta results to increase in
temperature of ponds by 5-10°C. This increased temperature increases the
rate of evaporation and hence causes faster precipitation of the halite
crystal (Litchfield et al., 2009).
2.7.3 Physiology of Dunaliella tertiolecta Cells
Dunaliella tertiolecta is a genus of unicellular algae belonging to the
family Polyblepharidaceae. It has become a convenient model organism
for the study of salt adaptation in algae. The establishment of the concept
of organic compatible solutes to provide osmotic balance was largely
based on the study of Dunaliella specie. Moreover, the massive
accumulation of β-carotene by some strains under suitable growth
conditions has led to interesting biotechnological applications. It cells lack
a rigid cell wall and they reproduce by longitudinal division of the motile
cell or by fusion of two motile cells to form a zygote (Oren, 2005).
Teodoresco described two species: D. tertiolecta and D. viridis. D.
tertiolecta has somewhat larger cells, and under suitable conditions it
synthesizes massive amounts of carotenoid pigments, coloring the cells
brightly red (Oren, 2005) and green. D. tertiolecta shows important
intraspecific variability in the β-carotene levels. This feature of the D.
tertiolecta is probably closely related to its nature of extremophile which
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 22
favors the natural growth of this alga in isolated environments such as
solar saltworks and hypersaline lakes (Mendoza et al,. 2008).
Dunaliella tertiolecta is distinguished by its ability to survive in a
certain range of salt concentrations through accumulation of intracellular
glycerol. It is one of the few species of microalgae that tolerates high levels
of sunlight, and can survive in the Tibet-Qinghai Altiplano, where UV
radiation is very strong. It is identified that D. tertiolecta possesses both
types of photolyas, and the gene of (6-4) photolyase from D. tertiolecta
(Ds64PHR) is the first one found in unicellular organisms (Lv et al., 2008).
2.7.4 Cultivation of Dunaliella tertiolecta
Similar to plants, Dunaliella tertiolecta is a mixotrophic algae that
utilizes both organic carbon and sunlight for food. Kumar et al. (2015)
provided in his work the contribution of individual factors affecting the
biomass growth of D. tertiolecta cultures using the fertilizer NPK 10-26-26.
Individual contributions were enumerated as follows: sunlight (76.52%),
NPK (16.14%), NaCl (4.84%), Temperature (2.27%) and NaHCO (0.22%).
With a large impact on biomass and carotenoid production, sunlight
becomes essential to evaporation.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 23
As D. tertiolecta proliferate in salt environments, salinities must be
maintained at a certain range for maximum biomass production. Based on
the study of Arun and Singh (2013), the maximum cell concentration of D.
tertiolecta cells grow best at 6% NaCl solutions. As illustrated in Figure 2.5,
increasing the concentration to 25% NaCl would significantly retard its
growth and halt it completely at 30% NaCl.
Figure 2.6 Growth curve of Dunaliella tertiolecta grown on different salt
concentrations. (Acquired from the Journal of the Marine Biological
Association of India Vol. 55, No.1, Jan-Jun 2013)
In order to attain an efficient bioreactor community, D. tertiolecta
cells must be cultivated on certain conditions in which algal growth is
optimum. Microalgal production requires large areas for sunlight capture.
As light does not penetrate more than a few centimeters through dense
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 24
algal culture, scale-up is based on surface area rather than volume (Scott
et al., 2010). For that reason, many different types of algal cultivation
systems have been developed. Some of the renowned methods of
microalgae culturing include the use of tanks, tubes, fermenters, open
ponds and many, grouped under the categories of open-air and closed
systems. There are several considerations as to which culture system to
use. Factors to be considered include: the biology of the alga, the cost of
land, labor, energy, water, nutrients, and climate if the culture is outdoors.
All very large commercial systems apply open-air system due to the
high cost needed in operating, maintaining and scaling-up of closed
systems. The advantage of closed systems however, allow the mass culture
of highly-selective microalgae by variation of the system’s environment.
They could be grown in closed systems photoautotrophically,
mixotrophically or heterotrophically.
Basically, the different closed methods implied categorize itself by
method of nutrient requirement in growth. Photoautothrophs like algae
and plants use sunlight for food, heterotrophs utilize organic carbon, and
mixotrophs are the combination of both (Stuart, 2013). Although the
implementation to such process noted varies depending on the culture
used, intensive labor and costs are conclusive in closed systems.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 25
In solar salterns, bioreactors consist of a biodiversity of benthonic
communities that are capable of withstanding high salinities (Litchfield et
al., 2009). Dunaliella tertiolecta exist along with other microorganisms like
flagellates, archaea, halobacteria, and many which serve their purpose in
this small ecosystem.
In order to cultivate D. tertiolecta, the control of predator and
competitor species is required and since D. tertiolecta is capable of living
in high saline environments, most of its competitors cease to exist
increasing efficiency of growth attained when D. tertiolecta is cultured
with its optimal environment. It can be observed in Figure 2.7 that
microalgae such as D. tertiolecta, exist with bacteria and protozoa in great
amounts in a salinity range less than its predator, artemia or more
commonly known as brine shrimp.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 26
Figure 2.7 Biodiversity that exists in varying salinities. (Dervied from Global
NEST Journal, Vol 11, No 1, p. 53, 2009)
The tolerance of each specie gives an analogous representation on
their purpose in a salt pond setting. With the purpose of improving the
production of salt, salterns utilizate such communities, produce salt for
industrial use (Korovessis and Lekkas, 2009).
2.8 Climatic Effects to the Evaporation of Brine
Evaporation is constituted by several factors explained generally by
simultaneous modes of heat and mass transfer. Difference in temperature and
bulk concentration acts as the driving force that facilitates vapor diffusion leading
to evaporation. When the temperature of water is increased, water molecules
gain more energy, moving faster and escaping at a faster rate. The higher the
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 27
temperature, the higher the rate of evaporation (Oroud, 2001). For brine, removal
of solvent produces a more concentrated yield and continually precipitates the
minerals as the number of water molecules per ion gradually decreases below a
certain minimum value.
A mass and energy balance that accounts all the affecting parameters
would be a viable method to arrive at a mathematical model for the evaporation
of brine with Dunaliella tertiolecta. According to Lensky et al. (2005), the energy
balance that accounts all identified parameters consist of: the net solar
radiation 𝑸𝑺𝑵, the net long-wave radiation 𝑸𝑳𝑾, the evaporative and conductive
heat flux, 𝑸𝑬 and 𝑸𝑪; the advected heat flux 𝑸𝑨𝑫; and the net heat flux 𝑸𝑵.
Figure 2.8 Energy Balance that accounts for all energy gains and losses.
(Acquired from the Water Resources Research, vol. 41, W12418, p. 5)
This yields an overall energy balance of:
𝑸𝑵 = 𝑸𝑺𝑵 − 𝑸𝑳𝑾 − 𝑸𝑬 − 𝑸𝑪 + 𝑸𝑨𝑫 (2)
since the mass balance of the system varies with the amount of water lost
due to evaporation, the growth and death of Dunaliella cells at constant initial
salinity or dissolved salt, a mass balance can be formulated where 𝒎𝒘 is the mass
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 28
of fresh water, 𝒎𝑫 is the mass of Dunaliella culture and 𝒎𝒔 is the mass of induced
dissolved salt.
𝒎𝒕 = 𝒎𝒘 + 𝒎𝑫 + 𝒎𝒔 (3)
2.8.1 Evaporation due to Net Radiation
Solar radiation aids in promoting evaporation by imparting energy
into the absorbing material. Radiation heat transfer utilizes all factors that
changes the temperature of the system through electromagnetic waves
and wavelengths ranging from 0.5 to 50 microns for visible light. Usually,
radiation is accounted by short-wave and long-wave frequencies. These
frequencies may come in directly to the system, while other frequencies
are contained inside the earth’s atmosphere due to greenhouse gases.
For very high temperature sources, such as solar radiation, relevant
wavelengths encompass the entire visible region (0.4 to 0.7 µm) and may
extend down to 0.2 µm in the ultraviolet (0.01- to 0.4-µm) portion of the
EM spectrum (Green and Perry, 2007). Given that radiation is a primary
contributor to the evaporation of brine, peak temperatures and solar
radiation recorded by weather observatories per time of day should be
taken into account in evaporation studies.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 29
2.8.2 Evaporation due to Combined Convection and Advection
Besides radiation, evaporation due to the differences between the
bulk fluids of the system and the environment is affected by convection.
Several factors such as relative humidity and wind speed affect vapor
diffusion and evaporation. As the two bodies are in contact with each
other, simultaneous heat and mass transfer occur as water particles
suspend into the atmosphere in vapor form. However, evaporation are
greatly affected by size or the surface area it covers.
The ‘oasis’ or the clothesline effect denotes that larger bodies of
water tend to have lower evaporation rates than those smaller in size due
to the tendency of larger basins to develop their own microclimate
resulting in increased humidity above the basin and a reduction in
evaporation from the basin (Leaney and Christen, 2000).
Basin parameters which includes soil also has an impact in a general
reduction in hydraulic conductivity if fresh water is induced. However, the
addition of saline water to sodic soils causes the clay to flocculate resulting
in the hydraulic conductivity of the soil (Leaney and Christen, 2000). This
hydraulic conductivity defines the leakage or seepage of brine in salt ponds
going into underground reserves and aquifers.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 30
CHAPTER 3
THE RESEARCH METHODS
The materials used in all experiments consist of industrial grade sodium
chloride (NaCl) crystals, tap water with an average total dissolved solids (TDS) of
105 ppm, 0.82 ppm residual chlorine, and pH ranging from 6 to 8. The microalgal
culture, Dunaliella tertiolecta, is utilized for all related experimentation which is
exclusively mass-cultured in Novaliches, Quezon City and Bolinao, Pangasinan by
Salinas Foods Incorporated. Culture samples were fertilized using fixed amounts
of NPK 14-14-14, and plastic-encapsulated fish remains. For turbidity testing, two
reference solution standards of 0 and 100 NTU were used to calibrate the PCE-
TUM 20 Turbidimeter.
3.1 Relationship of volume, salinity, and turbidity with the evaporation rate of
brine
Different parameters affect the evaporation rate of brine like brine salinity,
brine depth, and brine turbidity. Several environmental factors that also affect the
evaporation rate like temperature, humidity, wind speed and radiant energy,
could not be adjusted. Therefore, such parameters were only accounted to
provide viability for the amount of evaporation obtained from the experiments.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 31
3.1.1 Relationship of salinity to the evaporation rate of brine
Different brine setups were simulated using 0.5-meter diameter
cylindrical white basins. In order to quantify the relative difference
between different control samples, five control samples of clear brine with
salinities of 3, 5, 7, 9, and 11 °Bé were prepared by mixing tap water and
table salt. Salinities of the samples were measured using the Glass
Salinometer HX-1035 and brine depth was measured in millimeters (mm)
using Orion plastic ruler on an hourly basis. The sampling ran from 10 A.M.
in the morning until 5 P.M. in the afternoon. The salt concentration range
was set from 3 °Bé to 11 °Bé since Creswell (2010) indicated that the
seawater saline concentration starts from 3.5% (w/v), approximately 3 °Bé,
and the maximum concentration was set to 11 °Bé, based on the study of
Arun and Singh (2013) stating that Dunaliella tertiolecta begins to die at 11
°Bé.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 32
3.1.2 Relationship of volume to the evaporation rate of brine with
Dunaliella tertiolecta
Different brine setups with Dunaliella tertiolecta cultures were
prepared using five basins with salinities of 3, 5, 7, 9, and 11 °Bé by mixing
tap water, industrial grade salt and Dunaliella culture. All samples were set
to 10 L volumes to account for the demand of succeeding runs. Salinities
of the samples were measured using the Glass Salinometer HX-1035. Every
hour, both salinity and depth were monitored and brine depth was
measured in millimeters (mm) using Orion plastic ruler. The sampling ran
from 10 A.M. in the morning until 5 P.M. in the afternoon.
3.1.3 Relationship of the turbidity to the evaporation rate of brine
Brine turbidity is due to the presence of Dunaliella tertiolecta. This
greenish hue may be achieved at a certain turbidity range. For D.
tertiolecta, the range was set at 100 NTU to 400 NTU since 100 NTU or a
cell concentration of 1.3 X 106 cells/mL (Creswell, 2010) allows enough
microalgae to grow and resist death due to the given setup conditions.
Presence of other microorganisms may dominate the culture and consume
it once underpopulated (Stuart, 2013) thus justifies this value. For the
maximum turbidity, 400 NTU, was set based on the study of Venkatesen
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 33
et al. (2013) where the maximum cell concentration of Dunaliella
tertiolecta species lie on 8.6 X 106 cells/mL on the DeWalne’s medium.
However, its capacity may grow given the depth and the surface area of
the culture. And upon relevant observation, maximum turbidity attained
in culturing was found at 400 NTU.
3.1.4 Turbidity chart preparation
100 mL of culture from an assayed stock of Dunaliella tertiolecta at
7 °Bé and 400 NTU was placed in a 250 mL beaker. Two transparent 10 mL
vials were filled with the culture and were analyzed for turbidity using the
PCE-TUM20 Turbidimeter.
Figure 3.1 PCE-TUM20 Turbidimeter analyzing algae samples
The contents of one vial were returned to the stock, and 10 mL
water was added. The new culture was photographed using a 5 megapixel
(MP) phone camera to account for the color corresponding to the recorded
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 34
turbidity. This process was repeated until turbidity values became
constant at around 0 to 10 NTU. The photographs were arranged using
Adobe Photoshop CS6, where the corresponding colors of each were
extracted using the eyedropper tool. The colors were presented in a chart
labeled with their turbidities from 50 – 400 NTU.
3.1.5 Preparation of the brine with Dunaliella tertiolecta by continuous
reculturing
Cultures of different salinities and depth were formulated at
conditions where the biomass D. tertiolecta would grow best. Initially, 4
basins of D. tertiolecta culture were grown and monitored. The salinity,
brine depth, and turbidity of samples were recorded and the cultures were
exposed to sunlight and open air. The cultures were fed with 0.1 grams of
NPK 14-14-14 per 1 liter of culture in order to sustain the biomass and
improve algal growth.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 35
Figure 3.2 NPK 14-14-14 fertilizer used in promoting culture growth
After two days, measurements were taken to account for the
difference in salinity, depth, and turbidity. After which, the cultures were
then diluted to 2 degree Baume lower with that of their previous salinity.
This was to ensure culture survivability wherein salinities must not go
below 3°Bé or rise higher than 14°Bé.
3.2 Impact of Dunaliella tertiolecta on the Evaporation Rate of Brine
The impact of the culture to the evaporation rate of brine was realized
using the same experimentation performed in 3.1. Different brine setups with
brine only, brine with Dunaliella tertiolecta, and brine with Dunaliella tertiolecta
and soil bedding were ran simultaneously and the respective parameters were
measured every hour.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 36
3.3 Modeling and optimization of evaporation with Dunaliella-cultured brine
Modelling and optimization were completed using the Box-Behnken
Response Surface Method. This method has set the minimum number of trial runs
needed to randomize the experimentation procedure and produce optimization
data and scale-fit quadratic models. Design Expert 7 by Stat-Ease was utilized in
acquiring the necessary results. Three quantifiable parameters were set, namely
salinity, volume, and turbidity. With a saline range of 3-11°Bé, volume range of 10
– 20 L, and a turbidity range of 100 – 400 NTU, 17 randomized trial setups were
required in which the formulation of each setup was set by the program itself.
Once the setups were fixed to the desired system, they were exposed to
sunlight and open air conditions and were measured again after 24 hours.
Relevant data were taken and replicate trials were done to assess data reliability.
Data acquired from the three setups were interpreted through graphs
using Microsoft Excel 2013 by Microsoft Corporation. In order to create a
comparison between three different setups, the observed evaporation rate were
plotted against time for all categories presented in the experiment.
A response surface design was used in the development of the
experimental design. Specifically, a Box-Behnken design was used. Figure 3.1
shows the design parameters used in the optimization. Figure 3.2 shows the
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 37
generated experimental design. Both figures were obtained from Design Expert 7
(Trial Version) by Stat-Ease.
Table 3.1 Summary of experimental design parameters
Table 3.2 Final experimental design
Name Units -1 Level +1 Level
Salinity °Bé 3 11
Volume L 10 20
Turbidity NTU 100 400
Std. Run Salinity
(°Bé) Volume
(L) Turbidity
(NTU)
Actual Evaporation (mm/day)
7 1 3.00 15.00 400.00
10 2 7.00 20.00 100.00
14 3 7.00 15.00 250.00
5 4 3.00 15.00 100.00
2 5 11.00 10.00 250.00
8 6 11.00 15.00 400.00
16 7 7.00 15.00 250.00
4 8 11.00 20.00 250.00
13 9 7.00 15.00 250.00
12 10 7.00 20.00 400.00
1 11 3.00 10.00 250.00
17 12 7.00 15.00 250.00
11 13 7.00 10.00 400.00
6 14 11.00 15.00 100.00
15 15 7.00 15.00 250.00
3 16 3.00 20.00 250.00
9 17 7.00 10.00 100.00
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 38
The acquired data were analyzed as response, and the program ran specific
tests on fit, ANOVA, and model graphs using the Box-Behnken Response Surface
Design in Design Expert 7. Other factors which are uncontrollable like ambient
temperature, solar irradiation, wind speed, cloud cover and relative humidity
were monitored through online weather data from an observatory along
Kamuning St., Quezon City, which is near the test site. Controllable factors such as
amount of feed and dilution cycles were held constant to all trials.
Computations for brine volume were derived from the actual height of
brine when 1 L of brine was poured into the basin. As observed and measured, 1
L of brine corresponded to 4.7 mm in height. Thus, the formula used for converting
brine depth into volume for a 520.48 mm-diameter cylindrical basin was
𝑉 = 𝐻 ∗𝜋
4(520.482)
where V is the volume in liters, L or 𝑑𝑚3 , and H is the brine depth in
millimeters, mm. The amount of NPK 14-14-14 fertilizer placed per liter of culture
were also computed using the company’s heuristic data. For every liter of D.
tertiolecta culture, 0.1 g of powdered fertilizer should be dissolved into the culture
per week.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 39
Along the whole period of the experiment, the amount of fertilizer
dissolved in the culture was divided into the number of dilution cycles done per
week. Thus, the amount of fertilizer dissolved in each dilution of the culture was
𝑀 =0.1
𝑛×
𝐻
4.7
where M is the mass of the culture in grams, H is the height of brine in
millimeters, and n is the number of dilutions done per week.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 40
CHAPTER 4
RESULTS AND DISCUSSION
4.1 Relationship of volume, salinity, and turbidity to the evaporation rate of
brine
There are different parameters that affects the evaporation rate of brine
solution, since not all the parameters can be controlled such as the weather and
humidity, the researcher decided to use the parameters that are controllable
which are salinity, volume, and turbidity of the brine solution. In the experiment
each of these parameters were quantified in determining their relationship with
the evaporation rate of the brine solution.
4.1.1 Relationship of salinity to the evaporation rate of brine
Salinity is defined as the presence of salt in a solution and its
concentration affects the evaporation rate of water in a brine solution.
Since dissolved salts reduce the free energy of water molecules, water is
hindered from escaping as vapor to the surroundings. Salt concentration
range was set from 3 oBé to 11 oBé. This due to saltwater being available
at 3.5% (w/v) salinity or approximately 3 oBé. The maximum salinity was
set to 11 oBé since it is the salinity at which D. tertiolecta becomes
ineffective in multiplying (Arun and Singh, 2013). Table 4.1 shows a sample
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 41
data gathered to determine the relationship of salinity to the evaporation
rate of brine using height difference.
Table 4.1 Evaporation rates of brine in varying saline concentration
Brine Solution
Salinity, °Bé 3 7 11
Time Height, mm
10:15 AM 48 48 48
11:30 AM 48 46 47.5
12:45 PM 46.5 46 46
1:45 PM 45 44 44.5
2:45 PM 44 44 43
3:45 PM 44 43 42
4:45 PM 44 43 42
Graphing the figures, Figures 4.1 exhibits a linear decrease in height
with respect to time. For the three trials conducted, the 11 °Bé culture
attained the largest change in height compared to the other brine
solutions. The 3 °Bé culture gave the least difference in height with the
given time. The rates of 5, 7, and 9 °Bé setups showed congruency and
varied little with respect to their evaporation rate. In reference to the work
of Leaney and Christen (2000), the result of this experiment is coherent
with their conclusion that the evaporation factor decreases exponentially
with increasing salinity.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 42
Figure 4.1 Evaporation of Normal Brine
Though it contradicts the generalization that more saline solutions
tend to evaporate slower than less saline ones, this experiment was
situated in a salinity range that ensures the survivability of the microalgae.
Thus, all samples within the range of 30-100 g/L salinity would have
decreased the evaporation factor by around 4-6%.
4.1.2 Relationship of volume to the evaporation rate of brine with
Dunaliella tertiolecta
Volume is directly proportional to the evaporation rate. Since this
relationship is already known and existing, the volume and the
evaporation rate with the addition of Dunaliella tertiolecta was compared.
43
44
45
46
47
48
49
50
51
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght,
mm
Time
EVAPORATION OF NORMAL BRINE
3 °Bé 5 °Bé 7 °Bé 9 °Bé 11 °Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 43
Table 4.2 shows a sample of the evaporation rate with respect to the
change in height for the setup brine solution and brine with D. tertiolecta
solution.
Table 4.2 Evaporation of brine with Dunaliella tertiolecta with respect to height Brine Solution Brine with Dunaliella tertiolecta
Salinity,°Bé 3 7 11 3 7 11
Time Height, mm Height, mm
10:15 AM 48 48 48 48 48 48
11:30 AM 48 46 47.5 48 48 48
12:45 PM 46.5 46 46 48 47 48
1:45 PM 45 44 44.5 48 44 47
2:45 PM 44 44 43 47 44 47
3:45 PM 44 43 42 46 42.5 47
4:45 PM 44 43 42 46 42.5 47
To support the claim that the evaporation rate of brine would increase if
Dunaliella tertiolecta culture was introduced, basins with Dunaliella tertiolecta
culture in varying saline concentrations provided data on how different the
evaporation rate is compared to regular brine. Figures 4.3 shows the height with
respect to time of brine solution with Dunaliella tertiolecta culture.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 44
Figure 4.2 Height vs. Time for Brine with Dunaliella tertiolecta
Similar to Figure 4.1, Figure 4.2 shows a linear decline in height with
respect to time. Despite the similar trend, the final heights attained for Dunaliella
tertiolecta setups are significantly lower as compared to regular brine. The treated
results also show no difference between the final heights of 5 and 7 °Bé cultures.
In comparison, 3 °Bé gave the least change in height.
Table 4.3 Quantitative difference between regular brine and algae-cultured brine
Salinity (°Bè) Brine Only Brine with D. tertiolecta
Response Initial height (mm)
Final height (mm)
Initial height (mm)
Final height (mm)
3 50 45 50 46 Decrease
5 50 44.5 50 43 Increase
7 50 44 50 43 Increase
9 50 44 50 44 No change
11 50 43.5 50 44.5 Decrease
42
44
46
48
50
52
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght,
mm
Time
HEIGHT VS. TIME FOR BRINE WITHD. TERTIOLECTA
3 °Bé 5 °Bé 7 °Bé 9 °Bé 11 °Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 45
Quantifying the difference in evaporation between the brine and algae
cultured brine, Table 4.3 provides necessary proof of an increase in evaporation
rate of brine at 5 and 7 °Bé when D. tertiolecta cultures was incorporated in the
process. Cultures from 3, 9 and 11 °Bé however produced lower evaporation as
compared with regular brine. This may be justified by the hindrance of
evaporation due to the occurrence of slightly dying algae in the culture and
flocculation due to dust particles.
Figure 4.3 Discoloration and flocculation of D. tertiolecta cells
4.1.3 Relationship of the turbidity to the evaporation rate of brine
Since the Dunaliella tertiolecta gives the brine its turbidity, an increase in
the cell concentration increases the Turbidity of the solution. The cell
concentration was monitored to determine if on a two day interval there would
be a change in the evaporation rate of brine and to justify that the algae
concentration has an impact on the solution’s evaporation rate.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 46
4.1.4 Turbidity chart preparation
The turbidity chart was created for an easier measurement of the turbidity
of brine through qualitative analysis or by just looking at the physical color of the
samples and through comparison the turbidity can already be determined. Figure
4.4 shows the effect of dilution to the turbidity of the solution. It was observed
that the turbidity decreased linearly with the dilution of the culture in 10 mL
increments.
Figure 4.4 Impact of dilution to the turbidity of D. tertiolecta culture
The behavior of turbidity in constant dilution appeared linear as presented
in the figure. However as the dilution of the culture progressed, the decrease in
the turbidity becomes lesser at concentrations below 60% v/v. These changes
observed allowed the discontinuation of dilution since the turbidity started to be
constant at mixtures below 30% v/v.
0
50
100
150
200
250
300
350
400
0 0.2 0.4 0.6 0.8 1
TUR
BID
ITY,
NTU
Biomass Concentration, (%v/v)
Effect of Turbidi ty on Biomass Concentrat ion
Trial 1
Trial 2
Trial 3
Trial 4
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 47
4.1.5 Creation of the turbidity chart
After arriving with such relationship, the diluted 100 mL mixtures were
photographed and were arranged by their respective measurements.
As seen in Figure 4.5, the photograph of the samples were arranged in
grids, and the color of each culture were obtained using the “eyedropper tool” of
the photo editing software, Adobe Photoshop Cs6®.
Figure 4.5 Creation of turbidity chart using Adobe Photoshop Cs6®
The color of D. tertiolecta cultures from 400 NTU to 50 NTU were arranged
and labeled with their respective measurements. The final chart is presented in
figure 4.6. The proceeding experiments utilized this chart as basis for the turbidity
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 48
of samples. Values below 50 NTU were not included due to their transparency
which compares to clear water.
Figure 4.6 Turbidity chart with respective measurements
4.1.6 Preparation of the brine with Dunaliella tertiolecta with dilution cycles
This part of the discussion focuses on the cell concentration of the
Dunaliella tertiolecta with continuous dilution. Height is monitored to determine
if the evaporation rate, which is directly connected to the volume of the solution,
varies with the growth rate of the D. tertiolecta. The following sample tables were
obtained from May 2 to May 27 2015 because the month of May is the best suited
to make the experiment since it is summer and rainfall is not evident.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 49
Table 4.4 Salinity and height difference from May 2 to 4 Salinity (°Bé)
Difference Height (mm)
Difference Before After Before After
5 7 2 87 78 9
4 7 3 72 63 9
6 5 -1 73 61 12
6 9.5 3.5 67 55 12
Table 4.5 Salinity and height difference from May 4 to 6
Salinity (°Bé) Difference
Height (mm) Difference
Before After Before After
5 5 0 87 77 10
4 4 0 72 60 12
4.5 5 0.5 73 60 13
5 5 0 67 50 17
Table 4.6 Salinity and height difference from May 6 to 13
Salinity (°Bé) Difference
Height (mm) Difference
Before After Before After
5 8 3 87 60 27
4 6.5 2.5 70 50 20
5 7.5 2.5 99 75 24
5 7 2 92 64 28
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 50
Table 4.7 Salinity and height difference from May 16 to 25 Salinity (°Bé)
Difference Height (mm)
Difference Before After Before After
4 7.5 3.5 65 41 24
4 7.5 3.5 80 54 26
4.5 7.5 3 82 69 13
5 8.5 3.5 93 56 37
4 9 5 73 44 29
5 9 4 68 41 27
4 7 3 72 37 35
4 9 5 68 37 31
Table 4.8 Salinity and height difference from May 25 to 27 Salinity (°Bé)
Difference Height (mm)
Difference Before After Before After
5 5 0 66 60 6
5 4 -1 84 78 6
5 5 0 74 67 7
5 5 0 74 68 6
5 5 0 78 72 6
5 5 0 78 73 5
5 5 0 80 74 6
5 4 -1 76 69 7
Since the volume of the solution is directly proportional to the height, it
was the parameter monitored to determine if there is a larger change in
evaporation rate due to biomass growth through continuous dilution. Continuous
dilution is important not only for maintaining the salinity of the solution but also
necessary to provide ample space for biomass growth and restore the initial
heights of each basin.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 51
Figure 4.7 Difference between the height For March 2-4 and 4-6
Figure 4.7 shows the data gathered from a two-day interval from March 2-
4 and 4-6 2015, which presents a distinct change from the two two-day interval.
This shows an increase in the evaporation rate given the increase in height
difference of the samples. The factor that instigated this phenomenon was the
increase in cell concentration since for the two-day interval the salinity of the
solution was made constant by dilution and that the temperature and radiant
energy was also assumed constant since there were no rainfall or any obstructions
observed based on reference weather observatories.
As an example, Sample 1 in the graph has a change in height from March
2-4 2015 of 9 mm while in the next two days (March 4-6 2015), the change was
already 10 mm same as with the other samples, the change was very noticeable
0
5
10
15
20
1 2 3 4
9 912 12
1012 13
17
Hei
ght
dif
fere
nce
, m
m
Sample number
Difference Between the Height For March 2-4 and 4-6
March 2-4 2015 march 4-6 2016
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 52
especially in Sample 4 where the evaporation rate increased 5 units from the
original.
Figure 4.8 Difference between the height for March 4-6 and March 6-13
Since the evaporation rate was noticeable from a two-day interval, it was
validated if the assumption that a longer period of evaporation would still
applicable and if the evaporation rate will still be high. This assumption was
relative to the study of Arun and Singh (2013) that cell growth starts to decrease
if the salinity is critical in terms of the culture of D. tertiolecta.
As presented in Figure 4.8 where March 4-6 was compared to March 6-13,
Sample 1 was set to 5 °Bé with an initial height of 87 mm. After two days, there
was no observed change in salinity however there was a 10 mm change in height
unlike for the seven-day interval, where the salinity increase to 8 °Bé and a 27 mm
0
5
10
15
20
25
30
1 2 3 4
1012 13
17
27
2024
28
Hei
ght
Dif
fere
nce
, m
m
Sample no.
Difference between the height for March 4-6 and March 6-13, 2015
march4-6 2015 march 6-13 2015
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 53
difference from the initial height of the solution. A slower evaporation rate was
observed for Sample number 2 as seen in the Figure 4.9. The difference of a two-
day interval from the 7-day interval was minimal. It can be due to the salinity of
the solution being at 4 °Bé where culture growth in a lower salinities was
disfavored. The evaporation rate therefore decreased as an effect of the low
culture growth of the solution.
Figure 4.9 Difference between the height for March 16 to 25 And March 25 to 27
To be able to confirm the assumption, another trial was conducted using 8
samples. This was conducted using a 9-day difference from March 16 to 25 and a
2 day difference of March 25 to 27. The salinity of each sample from March 16 to
25 was fixed to a lower salinity at 4 to 5 °Bé to prevent the death of the culture in
0
5
10
15
20
25
30
35
40
1 2 3 4 5 6 7 8
2426
13
37
2927
3531
6 6 7 6 6 5 6 7
Hei
ght
Dif
fere
nce
, m
m
Sample no.
Difference between the height for March 16-25 And March 25-27 2015
march 16-25 2015 march 25-27 2015
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 54
the samples since it would be set for 9 days. The result showed that at 8 to 9 °Bé
the evaporation rate had started to slow down. This may be due to the salinity of
the solution wherein water molecules are being prevented by the salt molecules
to escape due to intermolecular forces.
4.1.7 Relative relationship of brine salinity, turbidity and volume
Using the Box-Behnken Response Surface Method, the relationship
between the used parameters was identified using the One Factor Interaction
view in Design Expert Trial Ver. 7.0.0. In Figure 4.10, the relationship of salinity
and volume can be observed.
Figure 4.10 One Factor Interaction between Volume and Salinity
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 55
It can be observed in Figure 4.10 that based on the experiment, salinity
did not have a significant implication on the volume of brine due to the parallel
orientation of curves. Upon extending the curved lines, there may be chances of
convergence which would explain the impact of salinity to volume. This finding
was similar to the interaction of salinity and turbidity. As seen in Figure 4.11,
salinity does have an impact on the turbidity of the solution as a possible converge
is anticipated when these curves are extended. This means salinity has a higher
impact to turbidity as compared to volume.
Figure 4.11 One Factor Interaction between Turbidity and Salinity
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 56
Figure 4.12 on the other hand, shows a clear diverge on the interaction
between volume and turbidity. This means that volume impacts turbidity greatly
and possibly creates an impact on the evaporation rate of cultured brine.
Figure 4.12 One Factor Interaction between Turbidity and Volume
4.2 Impact of Dunaliella tertiolecta on the evaporation rate of brine
The impact of Dunaliella tertiolecta on the evaporation rate of brine
solution can be verified or validated using the data on the changes in height and
salinity. Height and salinity can be used to validate the change in the evaporation
rate since height is directly proportional to the volume of water evaporated from
the brine solution, and an increase in the concentration of the brine solution
signifies that some of the solvent (water) has already vaporized to the
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 57
atmosphere. Shown in Table 4.9 and Table 4.10 the change in salinity and the
change in height respectively and both recorded on an hourly basis.
Table 4.9 Change of salinity due to evaporation of water from brine solution in an hourly basis
Brine Solution Brine with Dunaliella Brine with Dunaliella and Soil
Salinity(°Bé) 3 7 11 3 7 11 3 7 11
Time SALINITY (°Bé)
10:15 AM 3 7 11 3 7 11 3 7 11
11:30 AM 3 7.5 11 5 7 11 3.5 7.25 11
12:45 PM 3 7.5 11 5 7.5 11 3.5 7.5 11
1:45 PM 3 7.5 11 6 7.5 12 3.5 7.5 11.5
2:45 PM 3 7.5 11 6 8 12 3.5 8 12
3:45 PM 3 7.5 11 6 9 12.5 4 9 12.5
4:45 PM 3 7.5 11.5 7 10 12.5 4 9 12.5
Table 4.10 Decrease in height due to evaporation of water from brine solution in an hourly basis
Brine Solution Brine with Dunaliella Brine with Dunaliella and Soil
Salinity 3 7 11 3 7 11 3 7 11
Time HEIGHT
10:15 AM 48 48 48 48 48 48 48 48 48
11:30 AM 48 46 47.5 48 48 48 48 48 48
12:45 PM 46.5
46 46 48 47 48 48 48 47
1:45 PM 45 44 44.5 48 44 47 47 46 44
2:45 PM 44 44 43 47 44 47 46 43 44
3:45 PM 44 43 42 46 42.5 47 44 42 43
4:45 PM 44 43 42 46 42.5 47 43 41 40.5
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 58
One of the experiments performed focused on quantifying the evaporation
produced with different brine setups through hourly observation and
measurement. The setups were prepared in such a manner that it imitated actual
salt pond conditions. The difference in evaporation were quantified through
simulating the salt pond using a basin as experimental set-ups introduced with the
algae, Dunaliella tertiolecta, which serves as the potential promoter in increasing
the evaporation rate in salt ponds.
Evaporation of brine solution was observed and measured in 1-hour
intervals for almost 7 hours starting from 10 A.M. in the morning to 5 P.M. in the
afternoon. Three batches of 5 basins were prepared; brine solution only, brine
with Dunaliella tertiolecta, and brine with Dunaliella tertiolecta and soil. Having
fixed initial height for all the samples, the depth were measured with respect to
time. Three replicate trials were conducted on the different dates with good
weather conditions. These activities are illustrated in Figure 4.10.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 59
Figure 4.10 Experimental setups and data gathering procedure
Trial 3, being the most precise, was presented. Figures 4.11 shows the height vs.
time of brine solution.
Figure 4.11 Evaporation Rate of Brine Solution
Figures 4.11 exhibits a linear decrease in height with respect to time. For
the three trials conducted, the 11 °Bé culture attained the largest change in height
43
44
45
46
47
48
49
50
51
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght,
mm
Time
HEIGHT VS. TIME FOR BRINE ONLY SOLUTION
3 °Bé 5 °Bé 7 °Bé 9 °Bé 11 °Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 60
compared to the other brine solutions. The 3 °Bé culture gave the least difference
in height with the given time. The rates of 5, 7, and 9 °Bé setups showed
congruency and varied little with respect to their evaporation rate. In reference
to the work of Leaney and Christen (2000), the result of this experiment is
coherent with their conclusion that the evaporation factor decreases
exponentially with increasing salinity. Though it contradicts the generalization
that more saline solutions tend to evaporate slower that less saline ones, this
experiment was situated in a salinity range that ensures the survivability of
microalgae. Thus, all samples within the range of 30-100 g/L salinity would have
decreased the evaporation factor by around 4-6%.
To support the claim that the evaporation rate of brine would increase if
Dunaliella tertiolecta culture was introduced, basins with Dunaliella tertiolecta
culture in varying saline concentrations provided data on how different the
evaporation rate is compared to regular brine. Figures 4.12 shows the height
with respect to time of brine solution with Dunaliella tertiolecta culture.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 61
Figure 4.12 Height vs. Time for Brine with Dunaliella tertiolecta
Similar to Figure 4.11, Figure 4.12 shows a linear decline in height with
respect to time. Despite the similar trend, the final heights attained for Dunaliella
tertiolecta setups are significantly lower as compared to regular brine. The treated
results also show almost no difference between the final heights of 5 and 7 °Bé
cultures. In comparison, 3 °Bé gave the least change in height.
Table 4.11 Quantitative difference between regular brine and algae-cultured brine
Salinity (°Bè)
Brine Only Brine with D. tertiolecta Response
Initial height (mm)
Final height (mm)
Initial height (mm)
Final height (mm)
3 50 45 50 46 Decreased
5 50 44.5 50 43 Increased
7 50 44 50 43 Increased
9 50 44 50 44 No change
11 50 43.5 50 44.5 Decreased
42
44
46
48
50
52
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght,
mm
Time
HEIGHT VS. TIME FOR BRINE WITHD. TERTIOLECTA
3 °Bé 5 °Bé 7 °Bé 9 °Bé 11 °Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 62
Quantifying the difference in evaporation between the brine and algae
cultured brine, Table 4.11 provides necessary proof of an increase in evaporation
rate of brine at 5 and 7 °Bé when D. tertiolecta cultures was incorporated in the
process. Cultures from 3, 9 and 11 °Bé however produced lower evaporation as
compared with regular brine. This may be justified by the hindrance of
evaporation due to the occurrence of slightly dying algae in the culture and
flocculation due to dust particles like in the work of Saarani (2012) on flocculants.
Figure 4.13 Discoloration and flocculation of D. tertiolecta cells
Since the basins are white and very reflective, the impact of bed color was
considered. Soil was used in order to replicate actual salt ponds. On that regard,
the evaporation rate of D. tertiolecta samples with soil was assessed and Figure
4.14 shows the height of brine with Dunaliella tertiolecta and soil with respect to
time.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 63
Figure 4.14 Height vs. Time for Brine with Dunaliella tertiolecta and soil
Figures 4.14 also shows a linear decline in height with respect to time. The
final change in height for brine with Dunaliella tertiolecta with soil for 5 and 7 °Bé
samples is greatest than all other experimental set-ups. For three trials of these
set-ups, 5 and 7 °Bé gave the lowest final height comparing to 3, 9 and 11 °Bé.
Table 4.12 Quantitative difference between algae-cultured brine and algae-cultured brine with soil
Salinity (°Bè)
Brine with D. tertiolecta Brine with D. tertiolecta and Soil
Percentage Increased
(%) Initial height (mm)
Final height (mm)
Initial height (mm)
Final height (mm)
3 50 46 50 47.5 -37.5
5 50 43 50 43 0
7 50 43 50 42 14.29
9 50 44 50 48 -66.67
11 50 44.5 50 48 -63.64
4142434445464748495051
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Heig
ht, m
m
Time
HEIGHT VS. TIME FOR BRINE WITH D. TERTIOLECTA WITH SOIL
3 °Bé 5 °Bé 7 °Bé 9 °Bé 11 °Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 64
Table 4.12 shows the comparison of final heights of both clusters. It can be
seen that there has been a 14.29% increase in the evaporation rate of cultures
with soil compared to regular algae cultures. As observed, samples follow a
distinct trend with regards to the evaporation rate. This somehow allows the
generalization that 5 and 7 °Bé produce the greatest evaporation rate for D.
tertiolecta cultures within the set salinity range, and the impact of soil is
considerable to evaporation.
Upon comparison of the three clusters, the impact of salinity in different
setups was actualized. Figures 4.15, 4.16, 4.17, 4.18 and 4.19 shows the data on
the behavior of these clusters in specific salinities.
Figure 4.15 Evaporation of different brine samples at 3 °Bé
44
45
46
47
48
49
50
51
9:36 10:48 12:00 13:12 14:24 15:36 16:48
Hei
ght,
mm
Time
EVAPORATION OF DIFFERENT BRINE SAMPLES AT 3°BÉ
Brine Only Brine with Dunaliella Brine with Dunaliell and Soil
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 65
At 3 °Bé, it can be observed that the regular brine samples produced the
largest evaporation rate as compared with the other clusters. And upon further
observation, there is a steady and linear decrease in normal brine samples than
with Dunaliella-incorporated samples.
This phenomenon can be explained by the work of Vo and Tran (2014)
where low saline solutions tend to produce higher evaporation rates due to lower
electrostatic forces. Upon the addition of the culture, additional interactions
between water molecules and cells tend to change the physiology of water,
making it more viscous and changing increasing its pH.
Figure 4.16 Evaporation of different brine samples at 5 °Bé
In comparison with the 3 °Bé clusters, 5 °Bé samples exhibit a more linear
behavior in terms of evaporation. Brine with Dunaliella and brine with Dunaliella
42434445464748495051
9:36 10:48 12:00 13:12 14:24 15:36 16:48
Hei
ght,
mm
Time
EVAPORATION OF DIFFERENT BRINE SAMPLES AT 5 °BÉ
Brine Only Brine with Dunaliella Brine with Dunaliella and Soil
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 66
and soil exhibited more evaporation than with regular brine. This behavior can
be related to the findings of Arun and Singh (2013) where the growth of biomass
is highest at 6% NaCl concentrations. Closely similar to this range, this allows the
best environment for biomass proliferation and thus, may account for the
increase in evaporation rate due to increasing turbidity due to cell growth. This
finding is congruent with cultures at 7°Bé.
Figure 4.17 Evaporation of different brine samples at 7 °Bé
As presented in Figure 4.17, there are slight differences between the
evaporation rates of each cluster. However, brine with Dunaliella and soil
exhibited a different behavior with regards to its decrease compared with normal
brine and brine with Dunaliella. Despite of such, it can be regarded that the
impact of turbidity significantly affects brine evaporation.
4142434445464748495051
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght,
mm
TIME
EVAPORATION OF DIFFERENT BRINE SAMPLES AT 7 °BÉ
Brine Only Brine with Dunaliella Brine with Dunaliella and Soil
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 67
As seen in Figure 4.18 and 4.19 on brine clusters at 9 and 11 °Bé, it can be
generalized that the evaporation rate of clusters of normal brine and brine with
Dunaliella is higher compared to samples with soil. This may be due to the
apparent death of Dunaliella tertiolecta cultures as they tend to survive within a
certain salinity range.
Figure 4.18 Evaporation of different brine samples at 9 °Bé
43
44
45
46
47
48
49
50
51
9:36 10:48 12:00 13:12 14:24 15:36 16:48
Heu
ght,
mm
Time
EVAPORATION OF DIFFERENT BRINE SAMPLES AT 9 °BÉ
Brine Only Brine with Dunaliella Brine with Dunaliella and Soil
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 68
Figure 4.19 Evaporation of different brine samples at 11 °Bé
As observed in Figure 4.19, clusters with Dunaliella tertiolecta cultures
have attained lower evaporation rates than compared with the normal brine. This
could be attested relative to the work of Vo and Tran (2014) which mentioned the
impact of algae death on the intermolecular activity of brine solutions.
4.3 Modeling and optimization of evaporation with Dunaliella-cultured brine
The process parameters utilized in the experiment were brine salinity (A),
volume (B) and turbidity (C). The data gathered were analyzed and treated using
Design-Expert® Version 7.0.0 Trial Version. This software was able to generate a
model in a form of a quadratic equation shown in Equation 4.1 that allows the
prediction of the evaporation rate of brine with D. tertiolecta using the values of
the process parameters aforementioned.
434445464748495051
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght,
mm
Time
EVAPORATION OF DIFFERENT BRINE SAMPLES AT 11 °BÉ
Brine Only Brine with Dunaliella Brine with Dunaliella and Soil
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 69
𝐸 = +19.96146 + 2.13333𝐴 − 1.90167𝐵 − 0.089583𝐶 + 0.0000 𝐴𝐵
+ 4.16667𝐸 − 04𝐴𝐶 + 3.66667𝐸 − 03𝐵𝐶 − 0.15313𝐴2
+ 0.042000𝐵2 + 8.00000𝐸 − 05𝐶2 (Eq. 4.1)
Where E is the evaporation rate in mm/day, A is the salinity of brine in
degree Baumé (°Bé), B is the brine volume expressed in liters (L), and C is the
turbidity of brine in Nephelometric Turbidity Units (NTU).
To ensure the validity of the data gathered, a statistical analysis was
applied to test the differences among group means and their associated
procedures. Analysis of variance (ANOVA) checks whether the specific model
equation is statistically significant and is fit to represent the actual relationship
with response to factors. Upon data analysis, the fit summary derived from lack of
fit tests and model statistics suggested that the response surface quadratic model
is to be used. The ANOVA of such model is presented in Table 4.13.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 70
Table 4.13 ANOVA for the Response Surface Quadratic Model on Evaporation
Source Sum of Squares
Degrees of Freedom
Mean Square
F-Value p-value
Model 100.67 9 11.19 5.07 0.0219 significant
A 1.12 1 1.12 0.51 0.4984
B 15.13 1 15.13 6.85 0.0345
C 12.50 1 12.50 5.66 0.0489
AB 0.000 1 0.000 0.000 1.0000
AC 0.25 1 0.25 0.11 0.7463
BC 30.25 1 30.27 13.71 0.0076
A2 25.27 1 25.27 11.45 0.0117
B2 4.64 1 4.64 2.10 0.1903
C2 13.64 1 13.64 6.18 0.0418 Residual 15.45 7 2.21
Lack of Fit 2.25 3 0.75 0.23 0.8732 Not significant
Results from this analysis states that the Model F-value of 5.07 implies
that the model is significant, allowing a 2.19% chance that a “Model F-value this
large could occur due to noise.
The values of p-value less than 0.05000 indicate that the model terms
used are significant. In this case, B, C, BC, A2, and C2 are significant model terms.
The “Lack of Fit” value of 0.23 implies that it is not significant relative to the pure
error. This means there is an 87.32% chance that the “Lack of fit” value exists due
to large noise and is desirable in order for the model to fit.
Table 4.14 Fit of Model Parameters in Design Space
R-Squared 0.8669
Adj R-Squared 0.6959
Pred R-Squared 0.5123
Adeq. Precision 9.983
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 71
R-squared value of 0.8669 shows how close the data are to the regression
line. The Predicted R-Squared value of 0.5123 is viable and is in reasonable
agreement with the “Adj R-Squared Value” of 0.6959. A ratio of greater than 4 is
desirable for the “Adeq. Precision” value as it measures the signal to noise ratio.
With a value of 9.983, this model can be used to navigate the design space.
In order to verify the precision and the validity of the model equation 4.1,
the calculated values using the equation are compared to the actual evaporation
rate values. Table 4.15 shows the percent difference between the actual and
predicted values of the evaporation rate.
Table 4.15 Numerical Differences of Actual and Predicted Evaporation Rate Values
Std. Run Salinity
(°Bé) Volume
(L) Turbidity
(NTU)
Actual Evaporation (mm/day)
Predicted Evaporation
Rate (mm/day)
Percent Difference
(%) 7 1 3.00 15.00 400.00 5 5.37505 6.98
10 2 7.00 20.00 100.00 6 5.624707 6.67
14 3 7.00 15.00 250.00 6 5.39978 11.12
5 4 3.00 15.00 100.00 3 3.374935 11.11
2 5 11.00 10.00 250.00 3 2.999419 0.02
8 6 11.00 15.00 400.00 7 6.624465 5.67
16 7 7.00 15.00 250.00 4 5.39978 25.92
4 8 11.00 20.00 250.00 5 5.749394 13.03
13 9 7.00 15.00 250.00 3 5.39978 44.44
12 10 7.00 20.00 400.00 14 13.62483 2.75
1 11 3.00 10.00 250.00 3 2.250005 33.33
17 12 7.00 15.00 250.00 7 5.39978 29.63
11 13 7.00 10.00 400.00 5 5.374848 6.97
6 14 11.00 15.00 100.00 4 3.624349 10.36
15 15 7.00 15.00 250.00 7 5.39978 29.63
3 16 3.00 20.00 250.00 5 4.99998 0.00
9 17 7.00 10.00 100.00 8 8.374737 4.47
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 72
Most predicted values are coherent with the actual experimental values.
Large percent differences ranging from 10-45% may be brought about by
uncontrollable environmental factors leading to indeterminate errors. Table 4.16
contains information of the “p-value” values of model terms in each trial.
Replicate trials proved the validity of this data as the “p-value” values of each
model term were relatively similar and coherent.
Table 4.16 p-Values of Model Terms in Replicate Tests Trial 1 Trial 2
Model 0.0291 0.0325
Salinity (A) 0.4984 0.4769
Volume (B) 0.0345 0.0407
Turbidity (C) 0.0489 0.0588
The impact of salinity, volume, and turbidity to the overall evaporation
rate can be represented in a three dimensional surface graph. Figure 4.20 shows
the trend in the evaporation rate with respect to volume and salinity when the
turbidity is set to 100 NTU.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 73
Figure 4.20 3D Surface Plot of the Model Terms at 100 NTU cultures
It is observed that the highest evaporation rate can be achieved on 100
NTU cultures with salinities at 7 °Bé and 10 L culture volume. An evaporation rate
of 8.4 mm/day was achieved in a 100 NTU culture of D. tertiolecta at 7.11°Bé.
Upon increasing the turbidity to 250 NTU, it is observed in Figure 4.21 that
the peak of the contour shifted from low to high culture volumes. Regions with
higher evaporation rate lie from 5 to 9 °Bé, increasing with volumes from 15 to 20
L. This shift can be explained by most of the cultures in the experiment having
higher evaporation rates at higher volumes.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 74
Figure 4.21 3D Surface Plot of the Model Terms at 250 NTU cultures
At an optimal value, the highest evaporation rate achieved on 250 NTU
cultures is at 7.31°Bé and 20 L culture volume. Upon increasing the turbidity of
the culture to 400 NTU, it is observed that the contour began to stretch in a plane-
like incline. The highest evaporation rate of 13.67 mm/day was achieved on a 400
NTU culture at 7.51°Bé and 20 L volume.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 75
Figure 4.22 3D Surface Plot of the Model Terms at 400 NTU cultures
The effect of the set parameters in the evaporation rate of brine with D.
tertiolecta can be explained by figures 4.20, 4.21, and 4.22. Looking into the
impact of brine volume to the evaporation rate, it can be observed that a higher
volume leads to a higher evaporation rate. This is supported by its p-value of
0.0325 which can be derived from Table 4.13. In Figure 4.20, lower volumes at low
turbidity are desirable since they behave similarly with water. Liquids with smaller
volumes tend to evaporate faster given its smaller energy requirement for
vaporization. Oppositely in Figures 4.21 and 4.22, as the turbidity increased, a
higher culture volume is required to produce a higher evaporation rate.
Salinity and turbidity are both dependent on the brine volume. It shares
an inversely proportional relationship with salinity and a directly proportional
relationship with turbidity. As the volume of culture decreases, the culture
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 76
becomes more concentrated in salt. As for turbidity, experiments performed led
to the observation that deeper culture volumes are more turbid compared to
shallow ones. Higher culture volumes promote biomass growth which improves
the color of the culture. The darker the culture is, the more light is absorbed by
the culture. Thus, promote greater biomass production and faster evaporation
rates.
The effect of salinity to the evaporation rate is observed to be irrelevant.
Based on the p-value value of salinity in Table 4.13, and the following 3D surface
figures, the salinity for optimal evaporation lie at regions from 5 to 9 °Bé. Despite
of the large increase in turbidity, the optimal salinity only increased from 7.11 to
7.51 °Bé. This may be explained by the observation that cultures placed in low and
high salinities tend to die during the process due to its small salinity range. In that
accord, cultures with these salinities tend to clear out or become colored with
dead D. tertiolecta culture. This results to a lower evaporation rate as compared
to the optimal salinity range for the culture.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 77
CHAPTER 5
CONCLUSION AND RECOMMENDATION
5.1 Conclusions
With the intention of improving the evaporation rate of brine, Dunaliella
tertiolecta culture was incorporated in brine. Several methods applied helped
determine the relationship of the parameters to the evaporation rate, quantify
the amount of evaporation increased upon incorporation of the microalgae, and
identify the optimum amounts of parameters that would yield the highest
evaporation rate.
The parameters that had significant effect on the evaporation rate of brine
was brine volume (p=0.0345) and brine turbidity (p=.0489). Despite of the
importance of brine salinity (p=0.4954) as a factor, it only proved the optimal
salinity range where Dunaliella tertiolecta culture could be grown in order to
maximize the evaporation rate. Brine salinity was inversely proportional to the
evaporation rate. With the presence of the culture however, the salinity remained
in a specific range, making the culture a potential buffer for salinity. Brine turbidity
was directly proportional to the evaporation rate.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 78
The findings of this paper showed a 16 to 27% increase in evaporation rate
in mm/day for Dunaliella tertiolecta brine systems compared to regular brine at
similar salinities and optimal conditions.
Optimal conditions for maximizing brine evaporation on brine-cultured
systems were found at 7.52 °Bé, 20 L, and 400 NTU at 97% desirability. The
evaporation rate can also be computed using the following equation:
𝑬 = +19.96146 + 2.13333𝐴 − 1.90167𝐵 − 0.089583𝐶 + 4.16667𝐸 − 04𝐴𝐶
+ 3.66667 × 10−3𝐵𝐶 − 0.15313𝐴2 + 0.042000𝐵2
+ 8.00000 × 10−5𝐶2
where E is the evaporation rate in mm/day, A is the salinity of brine in degree
Baumé (°Bé), B is the brine volume expressed in liters (L), and C is the turbidity of
brine in Nephelometric Turbidity Units (NTU). Thus, it can be generalized that a
higher volume and culture turbidity greatly improves the evaporation rate. Since
a biological entity is incorporated in the process, brine must be maintained at 7 to
7.5 °Bé to achieve maximum evaporation.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 79
5.2 Recommendations
It is recommended to perform experiments in a longer time frame. This
would help understand the relationship of the considered parameters with the
evaporation rate. It is also recommended to do additional studies on the effect of
brine depth with the evaporation rate of brine with the culture since the effect of
depth can only be realized when seasonal changes occur.
It is also recommended use different types of fertilizers that would
effectively help improve microalgae growth. Dilution cycles should also be varied
due to changing weather, and alternative evaporation methods like aeration
should be tested.
It is suggested also to run optimization tests with varying dilution cycles in
order to observe the behavior of each parameter when the microalgae grows.
Experimentation with constant environmental conditions is also suggested in
order to determine which environmental factor greatly affects evaporation as a
whole.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 80
BIBLIOGRAPHY
Akridge, D. G. (2008). Methods for calculating brine evaporation rates during salt production. Journal of Archeological Science 35 (2008) pp 1453-1465.
Arun, N., and Singh, D.P. (2013). Differential responses of Dunaliella tertiolecta Isolated from brines in Sambar Salt Lake of Rajasthan (India) to salinities: zA study on growth, pigment, and glycerol synthesis. Journal of the Marine Biological Association of India, Vol. 55, No. 1, Jan-Jun 2013. pp. 6-9
Butinar, L., Sonjak, S., Zalar, P., Plemenitas, A. and Gunde, Cimerman, N. (2005). Melanized halophilic fungi are eukaryotic members of microbial communities in hypersaline waters of solar salterns. Bot Marina 48, 73–79.
Creswell, L. (2010). Phytoplankton Culture for Aquaculture Feed. Southern Regional Aquaculture Center Publication No. 5004. pp 1-2
Davis, J. (2000). Structure, function and management of the biological system for seasonal solar saltworks. Global Nest, the Int. J, Vol.2, No.3, pp 217-226
Green, D. and Perry, R. (2007). Perry's Chemical Engineers' Handbook, Eighth Edition. McGraw Hill Professional.
Korovessis, N., & Lekkas, T. (2009). Solar Saltworks' wetland Function. Global Nest, 49-57.
Leaney, F., & Christen, E. (2000). On-farm and community-scale salt disposal basins on the riverine plain: Evaluating the leak age rate, disposal capacity and plume development. CRC for catchment hydrology.
Lensky, N. G., Dvorkin, Y., and Lyakhovsky, V. (2005). Water, salt and energy balances of the Dead Sea. Water Resources Research, Vol. 41, W12418, doi: 10.1029/2005WR004084, 2005
Litchfield, C., Buckham, C., & Dalmet, S. (2009). Microbial diversity in hypersaline environments. Proceedings of the 2nd International Conference on the Ecological Importance of Solar Saltworks (CEISSA2009) Merida, Yucatan, Mexico, 26 – 29 March 2009 10.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 81
Lv., Qiao, Xiong, You, Cao, He, and Cao. (2008). Photoreactivation of (6-4)photolyase in Dunaliella Salina. College of Life Sciences, Sichuan University China. Doi: 10.1111/j.1574-6968.2008.01144.x
Mendoza, H., De La Jara, A., Freijanes, K., Carmona, L., Ramos, A.A., Duarte, V. d.S., Varela, J.C.S. (2008). Characterization of Dunaliella salina strains by flow cytometry: a new approach to select carotenoid hyperproducing strains. Electric Journal of Biotechnology Vol.11 No.4 ISSN: 0717-3458. Pontificia Universidad Catolica de Valparaiso-Chile
Naschon, U., Weisbrod N., Dragila M., and Grader, A. (2011). Combined evaporation and salt precipitation in homogeneous and heterogeneous porous media. Water Resources Research, Vol. 47, W03513, DOI: 10.1029/2010WR009677, 2011
Nguyen, S., Tran, D., Portilla, S., and Vo, T. (2014). Medium Improvement for Higher Growth and Longer Stationary Phase of Dunaliella. Journal of Plant Sciences. Vol. 2, No. 1, 2014, pp. 9-13. doi: 10.11648/j.jps.20140201.13
Oroud I.M. (2001). A new formulation of evaporation-temperature dynamics of saline solutions. Water Resources research, vol. 37, No.10, pp. 2513-2520, Oct. 2001
Oren, A. (2010). Thoughts on the "Missing Link" between saltworks biology and solar salt quality. Global Nest, 417-425.
Oren, A. (2011). The ecology of Dunaliella in high-salt environments. Journal of Biological Research-Thessaloniki (2014) 21:23 DOI 10.1186/s40709-014-0023-y
Ralefala, M. (2011). Evaluation of Dunaliella isolates from the Sua Pan (Botswana) solar salt evaporation ponds for production of beta-Carotene. University of Cape Town, South Africa
Saarani, N. (2012). Screening and optimizing metal salt concentration for marine microalgae harvesting by flocculation. pp.13
Sigler, A. and Bauder, J. (2015). TDS Fact Sheet. http://waterquality.montana.edu/. Montana State University. Retrieved 5 April 2015.
Stuart, H. (2013). Essential Microbiology (2nd ed.). Wiley-Blackwell. p. 86. ISBN 978-1-119-97890-9.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 82
Sundaresan, S., Ponnuchamy, K., Rahaman, A. (2006) Biological Management of Sambhar Lake Saltworks (Rajasthan, India), pp199-208
Tafreshi, A. H., and Shariati, M. (2008). Dunaliella biotechnology: methods and applications. Journal of Applied Microbiology ISSN1364-5072. Doi: 10.1111/j.1365 2672.2009.04153.x
Venkatesan, S., Swamy, M.S., Senthil, C., Bhaskar, S., and Rengasamy, R. (2013). Culturing Marine Green Microalgae Dunaliella salina Teod. And Dunaliella tertiolecta Masjuk in DeWalne’s medium for Valuable Feeds Stock. Journal of Modern Biotechnology, 2013. Vol. 2, No. 2. pp. 40-45. Madras Institute of Biotechnology
Vo, T. and Tran, D. (2014). Effect of salinity and light on growth of Dunaliella isolates. Journal of Applied & Environmental Microbiology, 2014. Vol. 2, No. 5, pp.208-211. Science and Education Publishing. Doi: 10.12691/jaem-2-5-2
Zhiling, J., & Guangyu, Y. (2006). The promotion of Salt quality through optimizing brine concentration: A new technique "Bidirectional Brine Concentration". 31-37.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 83
APPENDIX
Appendix A: Raw data for three-clustered experiment on brine, brine with Dunaliella, and brine with Dunaliella and soil
Table A.1 Trial 1 for raw data for the three-clustered experiment
Table A.2 Change in Salinity for Trial 1
Time
Height
Brine Only Brine with Dunaliella tertiolecta
Brine with Dunaliella tertiolecta and Soil
Salinity 3 5 7 9 11 3 5 7 9 11 3 5 7 9 11
10:15 48 48 48 48 48 48 48 48 48 48 48 48 48 48 48
11:30 48 46.5 46 46 46 48 48 47 47 47 48 46 48 48 48
12:45 46.5 45 46 46 46 48 47 47 47 47 48 45 47 48 48
13:45 45 45 44 45 44 46.5 45.5 46 45 44 48 43 43 48 48
14:45 44 44 44 44 43 46 45 44.5 44 44 47 42 43 48 47
15:45 44 44 43 43 42 46 43 43 43 43 46 41 41 47 47
16:45 44 44 43 43 42 45 42 42.5 42 42 46 41 41 46 47
Time
Change in Salinity
Brine Only Brine with Dunaliella tertiolecta
Brine with Dunaliella tertiolecta and Soil
Salinity 3 5 7 9 11 3 5 7 9 11 3 5 7 9 11
10:15 3 5 7 9 11 3 5 7 9 11 3 5 7 9 11
11:30 3 5.5 7.5 9 11 3.5 5.5 7.25 9 11 5 6 7 9.25 11
12:45 3 6 7.5 9 11 3.5 6 7.5 9 11 5 6 7.5 10 11
13:45 3 6 7.5 9 11 3.5 6 7.5 9 11.5 6 7.5 7.5 11 12
14:45 3 6 7.5 9 11 3.5 6.5 8 10 12 6 7.5 8 11 12
15:45 3 6 7.5 9 11 4 7 9 9 12.5 6 8 9 11 13
16:45 3 6 7.5 9 11.5 4 7 9 10 12.5 7 8.5 10 12 12.5
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 84
Table A.3 Trial 2 for raw data for whole day experiment
Table A.4 Trial 3 for raw data for One day experiment
Time
Height
Brine Only Brine with Dunaliella tertiolecta
Brine with Dunaliella tertiolecta and Soil
Salinity 3 5 7 9 11 3 5 7 9 11 3 5 7 9 11 10:10 51 51 51 51 51 51 51 51 51 51 51 51 51 51 51
11:20 50 49.5 49 49 49 51 50.5 50 50 50 51 49 50 51 51
12:30 48.5 48 49 49 48 50 49 49 49 49 51 47 49 51 50
13:30 47.5 47 47 48 46.5 49 47.5 48 48 47.5 50 45 46 50.5 50
14:30 46.5 46 46 47 45 48.5 46 47 47.5 46.5 49 44 45 49 50
15:30 46 46 45 46 44.5 48 45 46 46 45 48.5 43 44 48 49
16:30 45.5 45 45 45 44.5 48 44 44.5 44.5 44.5 48 43 43.5 48 49
Time
Height
Brine Only Brine with Dunaliella tertiolecta
Brine with Dunaliella tertiolecta and Soil
Salinity 3 5 7 9 11 3 5 7 9 11 3 5 7 9 11 9:55 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50
11:10 49.5 48.5 48.5 48 48 50 49 48.5 49 49 50 48.5 49 50 50
12:25 48 47.5 47 47 47 49 47.5 47 47.5 48 50 47 47.5 50 49
13:25 47 46.5 46 46.5 45.5 47.5 45.5 46 46.5 47 49 45.5 44 49 49
14:25 46 46 45 45 44.5 47 45 45.5 46 46 48 44 43 48.5 48
15:25 45 45 44 44 44 47 44.5 44 45 45 48 43 42.5 48 48
16:25 45 44.5 44 44 43.5 46 43 43 44 44.5 47.5 43 42 48 48
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 85
Figure A.1 Height vs. Time for Brine only for trial 1
Figure A.2 Height vs. Time for Brine with Dunaliella tertiolecta for trial 1
41
42
43
44
45
46
47
48
49
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE ONLY
3 Bé 5 Bé 7 Bé 9 Bé 11 Bé
41
42
43
44
45
46
47
48
49
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE WITH D.
TERTIOLECTA
3 Bé 5 Bé 7 Bé 9 Bé 11 Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 86
Figure A.3 Height vs. Time for Brine with Dunaliella tertiolecta and soil for trial 1
Figure A.4 Height vs. Time for Brine only for trial 2
42
44
46
48
50
52
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE WITH D.
TERTIOLECTA WITH SOIL
3 Bé 5 Bé 7 Bé 9 Bé 11 Bé
44
45
46
47
48
49
50
51
52
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE ONLY
3 Bé 5 Bé 7 Bé 9 Bé 11 Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 87
Figure A.5 Height vs. Time for Brine with Dunaliella tertiolecta for trial 2
Figure A.6 Height vs. Time for Brine with Dunaliella tertiolecta and soil for trial 2
42
44
46
48
50
52
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE WITH D.
TERTIOLECTA
3 Bé 5 Bé 7 Bé 9 Bé 11 Bé
42
44
46
48
50
52
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE WITH D.
TERTIOLECTA WITH SOIL
3 Bé 5 Bé 7 Bé 9 Bé 11 Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 88
Figure A.7 Height vs. Time for Brine only for trial 3
Figure A.8 Height vs. Time for Brine with Dunaliella tertiolecta for trial 2
43
44
45
46
47
48
49
50
51
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE ONLY
3 °Bé 5 °Bé 7 °Bé 9 °Bé 11 °Bé
42434445464748495051
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE WITH D.
TERTIOLECTA
3 °Bé 5 °Bé 7 °Bé 9 °Bé 11 °Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 89
Figure A.9 Height vs. Time for Brine with Dunaliella tertiolecta and soil for trial 3
Table A.5 Percentage Difference for Brine only and Brine with Dunaliella tertiolecta for trial 1
Salinity (°Bè) Brine Only Brine with D. tertiolecta Response (%) Initial height Final height Initial height Final height
3 50 45 50 46 -25
5 50 44.5 50 43 50
7 50 44 50 43 10
9 50 44 50 44 20
11 50 43.5 50 44.5 0
Table A.6 Percentage Difference for Brine with Dunaliella tertiolecta and Brine with Dunaliella tertiolecta for trial 1
Salinity (°Bè) Brine with D. tertiolecta Brine with D. tertiolecta and Soil
Response (%)
Initial height Final height Initial height Final height
3 50 46 50 47.5 -33.3333
5 50 43 50 43 16.6667
7 50 43 50 42 27.2727
9 50 44 50 48 -66.6667
11 50 44.5 50 48 -83.333
4142434445464748495051
9 : 3 6 1 0 : 4 8 1 2 : 0 0 1 3 : 1 2 1 4 : 2 4 1 5 : 3 6 1 6 : 4 8
Hei
ght
(mm
)
Time
HEIGHT VS TIME FOR BRINE WITH D.
TERTIOLECTA WITH SOIL
3 °Bé 5 °Bé 7 °Bé 9 °Bé 11 °Bé
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 90
Table A.7 Percentage Difference for Brine only and Brine with Dunaliella tertiolecta for trial 2
Salinity (°Bè) Brine Only Brine with D. tertiolecta Response (%) Initial height Final height Initial height Final height
3 50 45 50 46 -45.4545
5 50 44.5 50 43 16.6667
7 50 44 50 43 8.333
9 50 44 50 44 8.333
11 50 43.5 50 44.5 0
Table A.8 Percentage Difference for Brine with Dunaliella tertiolecta and Brine with Dunaliella tertiolecta for trial 2
Salinity (°Bè) Brine with D. tertiolecta Brine with D. tertiolecta and Soil
Response (%)
Initial height Final height Initial height Final height
3 50 46 50 47.5 0
5 50 43 50 43 14.2857
7 50 43 50 42 15.3846
9 50 44 50 48 -53.8462
11 50 44.5 50 48 -69.2308
Table A.9 Percentage Difference for Brine only and Brine with Dunaliella tertiolecta for trial 3
Salinity (°Bè) Brine Only Brine with D. tertiolecta Response (%) Initial height Final height Initial height Final height
3 50 45 50 46 -20
5 50 44.5 50 43 27.27
7 50 44 50 43 16.67
9 50 44 50 44 0
11 50 43.5 50 44.5 -15.38
Table A.10 Percentage Difference for Brine with Dunaliella tertiolecta and Brine with Dunaliella tertiolecta for trial 3
Salinity (°Bè) Brine with D. tertiolecta Brine with D. tertiolecta and Soil
Response (%)
Initial height Final height Initial height Final height
3 50 46 50 47.5 -37.5
5 50 43 50 43 0
7 50 43 50 42 14.29
9 50 44 50 48 -66.67
11 50 44.5 50 48 -63.64
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 91
Appendix B: Raw data for evaporation rate of brine with Dunaliella tertiolecta cultured with variable dilution cycles
Table B.1 Raw data for periodic dilution (March 2-4, 2015)
Salinity Difference
Height Difference
before after before after
5 7 2 87 78 9
4 7 3 72 63 9
6 5 -1 73 61 12
6 9.5 3.5 67 55 12
Table B.2 Raw data for periodic dilution (March 4-6, 2015)
Salinity Difference
Height Difference
before after before after
5 5 0 87 77 10
4 4 0 72 60 12
4.5 5 0.5 73 60 13
5 5 0 67 50 17
Table B.3 Raw data for periodic dilution (March 6-13, 2015)
Salinity Difference
Height Difference
before after before after
5 8 3 87 60 27
4 6.5 2.5 70 50 20
5 7.5 2.5 99 75 24
5 7 2 92 64 28
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 92
Table B.4 Raw data for periodic dilution (March 16-25, 2015) Salinity
Difference Height
Difference before after before after
4 7.5 3.5 65 41 24
4 7.5 3.5 80 54 26
4.5 7.5 3 82 69 13
5 8.5 3.5 93 56 37
4 9 5 73 44 29
5 9 4 68 41 27
4 7 3 72 37 35
4 9 5 68 37 31
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 93
Appendix C: Turbidity chart creation raw data Table C.1 Raw data of turbidity of samples with dilution of water
Turbidity (NTU)
Run # TRIAL 1 TRIAL 2 TRIAL 3 TRIAL 4
0 400 400 400 400
1 367 357 361 359
2 327 325 330 327.5
3 285 285 290 287.5
4 247 240 248 244
5 212 211 209 210
6 178 176 177 178
7 143 140 145 142.5
8 126 126 127 126.5
9 114 114 115 114.5
10 102 101 105 103
11 90 91 92 91.5
12 81 80 82 81
13 73 73 72 72.5
14 65 64 64 64
15 58 56 57 56.5
16 52 52 51 51.5
17 46.41 45.88 44.21 45.045
18 41.86 40.4 40.2 40.3
19 36.96 36.9 35.7 36.3
20 33.9 33.58 33.1 33.34
21 31.62 30.69 31.5 31.095
22 28.28 26.16 27.22 26.69
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 94
Appendix D: Raw data of Second Trial on the Optimization Experiment
Table D.1 Second Randomized test with Actual Response by Design Expert Trial 7.0.0
Std Run Block Factor 1 A:
Salinity °Bé
Factor 2 B:
Volume L
Factor 3 C:
Turbidity NTU
Response Evaporation/Day
mm
7 1 Block 1 3.000 15.00 400.00 4
10 2 Block 1 7.00 20.00 100.00 5
14 3 Block 1 7.00 15.00 250.00 5
5 4 Block 1 3.00 15.00 100.00 4
2 5 Block 1 11.00 10.00 250.00 3
8 6 Block 1 11.00 15.00 400.00 7
16 7 Block 1 7.00 15.00 250.00 6
4 8 Block 1 11.00 20.00 250.00 5
13 9 Block 1 7.00 15.00 250.00 3
12 10 Block 1 7.00 20.00 400.00 13
1 11 Block 1 3.00 10.00 250.00 3
17 12 Block 1 7.00 15.00 250.00 7
11 13 Block 1 7.00 10.00 400.00 5
6 14 Block 1 11.00 15.00 100.00 4
15 15 Block 1 7.00 15.00 250.00 7
3 16 Block 1 3.00 20.00 250.00 5
9 17 Block 1 7.00 10.00 100.00 7
Table D.2 Selection of Type of Fit by Design Expert Trial 7.0.0
Sequential Model Sum of Squares Test
Source Sum of Squares
df Mean Square
F Value
p-value Prob > F
Mean vs Total
508.76 1 508.76
Linear vs Mean
23.75 3 7.92 1.50 0.2603
2FI vs Linear 27.25 3 9.08 2.20 0.1507
Quadratic vs 2FI
27.29 3 9.10 4.56 0.0450 Suggested
Cubic vs Quadratic
2.75 3 0.92 0.33 0.8071 Aliased
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 95
Table D.3 Analysis of variance table
Analysis of variance table [Partial sum of squares-Type III]
Source Sum of Squares
df Mean Square
F value P-value Prob>F
Model 78.29 9 8.70 4.36 0.0325 significant
A-Salinity 1.12 1 1.12 0.56 0.4769
B-Volume 12.50 1 12.50 6.27 0.0407
C-Turbidity
10.13 1 10.13 5.08 0.0588
AB 0.000 1 0.0000 0.0000 1.0000
AC 2.25 1 2.25 1.13 0.3233
BC 25.00 1 25.00 12.54 0.0094
A2 19.92 1 19.92 9.99 0.0159
B2 1.39 1 1.39 0.70 0.4309
C2 7.39 1 7.39 3.71 0.0955
Residual 13.95 7 1.99
Lack of Fit 2.75 3 0.92 0.33 0.8071 Not significant
Pure Error
11.20 4 2.8
Cor Total 92.24 16
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 96
Appendix E: Sample online weather data from Manila Observatory
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 97
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 98
Appendix F: Conversion of Nephelometric Units to Cell Density
Table F.1 Turbidity (NTU) to mg/L relationship
Std # 1 2 3 4 5
NTU 20 75 250 450 750
mg/L 40 100 420 1250 3300
Figure F.1 Organic wt. of Dunaliella tertiolecta: 85 𝑝𝑔/𝑐𝑒𝑙𝑙 (Creswell, 2010)
(𝑇𝑢𝑟𝑏𝑖𝑑𝑖𝑡𝑦)𝑚𝑔
𝐿×
𝑐𝑒𝑙𝑙
85 𝑝𝑔 ×
1000000000𝑝𝑔
1𝑚𝑔
𝐿
1000 𝑚𝐿×
1
106 = 𝑐𝑒𝑙𝑙𝑠 × 106/𝑚𝐿
Table G2. NTU conversion to Cells x 106/mL
NTU 50 55 60 65 70 80 90 100 110
Cells x 106/mL
0.76 0.8 0.85 0.9 1.0 1.1 1.2 1.3 1.5
NTU 130 140 180 210 250 280 330 360 400
Cells x 106/mL
1.8 2.0 3.0 3.8 5.1 6.2 8.3 9.7 11.8
y = 0.0056x2 + 0.1592x + 42.489R² = 0.9999
0
500
1000
1500
2000
2500
3000
3500
0 100 200 300 400 500 600 700 800
Regression curve for turbidity (NTU) to mg/L
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 99
Appendix G: Timetable for research
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 100
Appendix H: Identification of Costs and Budgetary Requirements
Materials
Quantity
Cost Per Piece (Php)
Cost Of Total (Php)
Basin 15 220 3300
Beaker 1 @ 1L 580 580
1 @ 250mL
120 120
Thermometer 1 Borrowed -
Salinometer 1 Borrowed -
pH meter 1 Borrowed -
Turbidimeter 1 Borrowed -
Soil Supplied by Salinas
Water Supplied by Salinas
Table Salt (Industrial grade)
25 23/pack 575
Dunaliella tertiolecta cuture
Supplied by Salinas
Swire feed (NPK 14-14-14)
1 1500/sack 1500
Total Cost 6075
Remarks
All research costs were covered by
Salinas Foods Incorporated
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 101
Curriculum Vitae
Kenneth Saniano Caraig, a 5th year
student from the University of Santo Tomas with
a program, Bachelor of Science in Chemical
Engineering, was born on August 5 1994. He was
the youngest son of Estelita Saniano and Ismael
Caraig. His only brother, Jhon Fritz Kevin Saniano
Caraig, is currently studying Medicine. They live in
#322 brgy. Tibig Lipa City Batangas. He was a high school graduate from De La Salle
Lipa in 2011 where he got his loyalty award. He was currently studying at UST on
his last term as a fifth year student. His stay in college made him a more confident
person. He joined organizations such as the UST Chemical Engineering Society
where he was a staff in the Performing Arts Recreations Committee, he is also a
member of the Pax Romana in UST. Aside from that, He is also the current vice
president of their section, which made him a more responsible person.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 102
Alyssa Alicaway Rivera is a 5th year
engineering student major in B.S. Chemical
Engineering at University of Santo Tomas. She
graduated valedictorian at Bernardo College
Children’s Camp in her primary level and awarded
as one of the 13 outstanding students out of 400
graduates in her secondary level. To further excel
herself academically, she also engage in different organizations that will nurture
her current knowledge about her program she’s taking like Chemical Engineering
Society (ChES) and Philippine Institute of Chemical Engineers (PICHE). She also
involves in extracurricular activities to learn from people and experience, and to
discover more about herself. She is a varsity player of table tennis in high school.
She also become part of different organizations related to dancing like Engineering
Dance Troupe, Chemical Engineering Dance Crew. These organization helps her to
develop her multi-tasking skills and time management. She’s also part of UST Red
Cross Youth Council-Eng’g Unit as Junior Officer. She is a competent,
compassionate, and committed future Thomasian Chemical Engineer. She is eager
to learn and she is willing to impart her knowledge. Hardworking and dedication
are some of the values she can confidently proud of.
UNIVERSITY OF SANTO TOMAS CHEMICAL ENGINEERING 103
Jericho Bolok Zacarias is a 5th year
Chemical Engineering Student at the University
of Santo Tomas that had taken his secondary
education in Bacoor, Cavite, which is near his
hometown. Currently, he is taking up a course
on Bachelor of Science in Chemical Engineering
in the University of Santo Tomas, Espana,
Manila and is expected to finish on the School Year 2016. His aim is to develop a
skill in approaching different Engineering problems and be able to cope to new
challenges preented by novel problems and complications. He was a member of
the Chemical Engineering Society Public Relations Committee for 2 consecutive
years to present, and was awarded with recognitions in the said organization. He
also participated in various seminars with regards to food, polymerns, medicine,
and nanotechnology industries in view of acquisation of greater knowledge of the
various industires of Chemical Engineering. He is currently undertaking in an
undergraduate thesis program which is duly sponsored by Salinas Foods
Incorporated that aims to quantify evaporation difference of Dunaliella-cultured
brine to the regular brine.