Wastewater Treatment Process

7/28/2019 Wastewater Treatment Process

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Wastewater Treatment Process


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What is Wastewater Treatment ?

refers to the process of removing

pollutants from water previously employed

for industrial, agricultural, or municipaluses.


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Where does wastewater come

from?

Homes - human and household wastes from toilets,

sinks, baths, dishwashers, garbage grinders, clothes

washers and drains.


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Industry, Schools

and Business

chemical and other

wastes fromfactories, food-

service operations,

school activities,

shopping centers,etc.


from?


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Hospitals


from?

From urinals and toilets

From LaundryFrom Kitchen/Canteen

From Patient-handling

Typical wastewater sources:


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Why treat wastewater?

Compliance with The Clean Water Act of 2004

(Republic Act 9275)

Stiff penalties:

Php 10,000 to Php 200,000 a day for every day of

violation

Imprisonment for not less than 2 years


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Compliance with DENR

Effluent Standard

Pollutants DENR-EMB Standard

Biochemical Oxygen

Demand (BOD)

50 mg/l

Chemical Oxygen

Demand (COD)

100 mg/l

Total Suspended Solids

(TSS)

70 mg/l

Color 150Oil & Grease 5 mg/l

pH 6.5 9.0


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Typical Wastewater

Treatment Facility

Preliminary treatment in the Philippines is typically

handled by septic tanks.

Usually includes the removal of large solids from the

wastewater via physical settling or filtration.

Typical Septic Tank Design

Scum


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Types of Secondary Treatment

1. Sequencing Batch Reactor (SBR)

2. Anaerobic Baffled Reactor (ABR)

Outflow

Outflow

From Primary Treatment



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Secondary Treatment:

3. Membrane Bioreactor (MBR)

4. Rotating Biological Contactor (RBC)


Clarifier Tank

Outflow


Outflow


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Five Stages to Treatment:

Sequencing Batch Reactor

From Primary Treatment Wastewater

Gradual release of treated water

Wastewater coming into the tank

Aerobic bacteria eats

organic matter in the

wastewater

Anaerobic bacteria flourish

at the bottom of the tank.

Seeding and waiting for the

next batch


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ADVANTAGES DISADVANTAGES

It maintains a consistent quality

of the effluent which is possible

due to the tranquil batch settlingmethod

Though it requires less

attention, it needs a skilled

operator

It is suitable for use with low

volume inflow in wastewater

treatment plants where the flowlevel varies widely

The reactor needs regular

maintenance and should be

inspected periodically

It allows flexible operational

levels that allows you to control

and filter out nutrients from the

wastewater

Some users have faced

problems during the release

process



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It is less operator-attention

intensive when compared with

some of the mechanicaltreatment methods

Needs large space requirement

It is a simple method of treatment

and also reliable at the same time

Fixed volume capacity thus

difficult for upgrading

Longer construction time(5-6months) due to civil works and

series of components



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Maybe difficult to effect

maintenance on the pipes and

fittings set-up as this isinstalled at the bottom of the

tanks

Foul smell during aeration



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Anaerobic Baffled Reactor

Is an improved septic tank because of the series

of baffles under which the wastewater is forced

to flow.

The increased contact time with the activebiomass (sludge) results in improved treatment.
http://www.akvo.org/wiki/index.php/File:Anaerobic_baffled_reactor.png


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The majority of settleable solids are removed in

the sedimentation chamber at the beginning of

the ABR, which typically represents 50 % of the

total volume.

OutflowFrom Primary Treatment


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No electrical energy required. Requires constant source of

water(maybe a bit costly)

Can be built and repaired withlocally available materials. Effluent may require furthertreatment due to shock loads.

Long service life. Low reduction pathogens

Moderate capital costs,

moderate operating costs

depending on emptying; can be

low cost depending on number

of users.

Requires expert design and

construction.


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Pre-treatment is required to prevent

clogging.

The ABR will not operate at full

capacity for several months after

installation because of the long start

up time required for the anaerobic

digestion of the sludge.

Because the ABR must be emptied

regularly, a vacuum truck should be

able to access the location.

Clogging may result to odor emission.


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Clogging may result to overflow and

may not perform well due to poor

treatment period.Fixed volume capacity and difficult for

upgrading.

ABR Sample Design

Outflow



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Membrane Bioreactor

MBR is the combination of a membrane

process (filtration) with a suspended

growth bioreactor.
http://en.wikipedia.org/wiki/File:MBR_Schematic.jpg


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Continuous removal of oil and

grease from membrane operating

environment

Fouling

The MBR filtration performance

inevitably decreases with filtration

time. This is due to the depositionof soluble and particulate

materials onto and into the

membrane.

Automated, in-place membrane

cleaning process means reducedlabor

Safe environment for plant

operators

Flexibility in biological processselection/optimization

Membrane Bioreactor
http://en.wikipedia.org/wiki/File:MBRfouling.jpg


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High Maintenance Cost

Proprietary of anti-fouling products. In

addition, different types/intensities of chemical

cleaning may also be recommended: Chemically enhanced backwash(daily);

Maintenance cleaning with higher

chemical concentration (weekly);

Intensive chemical cleaning (once or

twice a year).

Consumables maybe costly

Require constant monitoring because of

possible clogging of the membrane

Membrane Bioreactor


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Rotating Biological Contactor

Rotating biological contactors are fixed-film reactors.

This technology involves allowing wastewater to come in

contact with a biological medium in order to facilitate the

removal of contaminants. The support media for microbial growth are the slowly

rotating discs that are partially submerged in flowing

wastewater in the reactor.


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The RBC process consists of a large disc, usually

plastic, slowly rotating in a tank. The large disc and

periodic exposure to atmosphere shall allow quick

growth of bacteria that will eat organic matters inwastewater.

Filter Media


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During the rotation, about 40 percent of the media surface

area is in the wastewater. The rotation and subsequent

exposure to oxygen allows organisms to quickly multiply

and form a thin layer of biomass in the media.

This large, active population causes faster biological

degradation of organic pollutants.

Excess biomass shears off at a steady rate and is then

carried through the RBC system for removal in a clarifier

tanks.


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Short contact periods are

required because of the large

active surface

Requirement for covering RBC

units against rain to prevent

overflow.

They are capable of handling a

wide range of flows

Shaft bearings and mechanical

drive units require frequent

lubrication

Sloughed biomass generally has

good settling characteristics and

can easily be separated from

waste stream

Ability to handle shock load.



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Operating costs are low because little

skill is required in plant operation

Cyclonic feature will readily separategrease and oil.

Short retention time

Low power requirements

Low sludge production and excellent

process control

Simple mechanical structure.



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Only need small space

(Size of a van!)

Modularity thus allowing to expandin the future as the capacity of

effluent is increasing.

For Fiber Reinforced type, the unit

can be readily transferred to otherdesired location.

Good track record(DENR is using one, ADB financed one!)



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Consistent process results

Stable operation without frequent

supervisionLower expansion and retrofit costs

due to modular construction and

reduced excavation

Low energy consumption (3 kWper 3,000 people)

The only maintenance required is

simple drive and bearing

lubrication



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Operator friendly

Easily modified for upgrades,

retrofits and multiple applications23 installed units all over the

Philippines with 4 installed at

hospitals.



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Thank You!


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Cleantech Innovations

Oliver F. DumlaoSr. Manager, Business Development

0922-867-5805

G/F Pacific Coast Plaza, Tambo, Paraaque City

879-83-81 / 879-81-03

www.cleantech.com.ph

[email protected]

Wastewater Treatment Process

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