WASTEWATER TREATMENT SYSTEMSBY: AHMED ALHAMADAT

What is (in) Wastewater?

Water Quality ConcernsContaminants of Concern: Pathogens

– Bacteria, viruses, protozoa

Inorganic chemicals – Total dissolved solids

Unregulated and unidentified trace organic chemicals– Pharmaceuticals– Personal care products and

household chemicals– Endocrine disrupting chemicals– Emerging disinfection by-products

Pharmaceutically active compounds (PhACs)

Coliform count is usually 105 – 106 /mL in raw sewage

Wastewater Characteristics Wastewater refers to liquid discharged from residential,

business buildings and institutions.Industrial wastewater is discharged from manufacturing

plants. Municipal wastewater is the general term applied to the liquid

collected in sanitary sewers and treated in municipal plants Domestic sewage is composed of human body waste and

sludge which is the wastewater resulting from personal washing, laundry, and cleaning of kitchen utensils

• Raw wastewater chemical constitutes (mg/l): BOD COD TSS metals TN TP 100-500 300-800 100-350 <1 20-85 4-15

Water recycling is reusing treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, and ground water recharge – USEPA Region 9 Water Program

Recycled or reclaimed water is water that is used more than one time before it passes back into the natural water cycle. – Water Reuse Association

•Wastewater

- Environmental Problem- Finite Resources- Water Shortage

New Water Resource

“ Reuse”

WW Treatment

Energy

Technology

Experience

Treatment Technologies

Conventional Natural (CWs & MAR)

Low Energy

No Chemicals

Robust

Energy

Chemicals

WaterwithHigh

Quality

Objectives of WWT

Reduce organic content (BOD & COD) and TSS

Removal/reduction of nutrients i.e., N,P

Removal/inactivation of pathogenic microbes

Typical Stages in a Conventional Wastewater Treatment Operation

(Arani Kajenthira et al, 2012)

Wastewater production, treatment and reuse in Saudi Arabia, 2009

14% reused only

26% collected

80% treated

Potential energy savings from increasing the use of treated wastewater rather than desalination in the municipal sector

How do we clean our wastewater?

Energy:PumpingMixingAerationDisinfectionHeat for digester Chem

transportation

Chemicals:FlocculationPrecipitationDisinfection

Labor:O&M

Clean water

BioproductsBiosolids, Nutrients,

biopolymers

Unrecoverable waste

residuals

Energy?

Trace chemicals,

VOCs

CO2CH4

H2S

A more sustainable approach

Problems associated with WW reuse The real cost of the projects are usually considerably

higher than that estimated previously. This is in large part a result of insufficient planning before design and construction of water reclamation projects

Presence of pathogens in water, chemical contaminants or heavy metals because of insufficient treatment

The positive effects of using wastewater irrigation

Economic feasible water resource

It conserves potable water

It reduces pollution of receiving water bodies e.g. rivers, canals and other surface water resources

It decreases the needs for chemical fertilizers

It increases crop yields

It provides a reliable water supply to farmers

The potential negative effects of wastewater irrigation

Health risks for irrigators and communities with prolonged contact with untreated wastewater and consumers of vegetables irrigated with wastewater

Contamination of groundwater (nitrates)

Build-up of chemical pollutants in the soil (heavy metals)

Creation of habitats for disease vectors

Excessive growth of algae and vegetation in canals carrying wastewater (eutrophication)

Challenges associated with WW reuse

1. Social acceptance (farmers, retailers and consumers): This is the most sensitive area of this topic. Farmers are not going to reuse water, if their product cannot be sold. Consumers will not buy products where reuse water was used unless it is proven to be safe

2. Social issues: play a significant role in water reuse initiatives and should be adequately addressed. With adequate political will accompanied by awareness programmes these cultural, religious and social objections can be overcome.

3. Water quality monitoring: TE should be tested on regular basis to guarantee the matching with standards

The non-regulated use of treated water in agriculture The non-existing reuse criteria related to hygiene, public

health and quality control The non-existing reuse criteria related to irrigation

techniques, degree of wastewater treatment, and choice of areas and types of crops to be irrigated

The lack of efficient control and monitoring of urban wastewater treatment plants

The lack of trained personnel both in the competent authorities and the treatment plants

The low level of awareness of the farmers and the public at large

Wastewater as a renewable resource

A paradigm shift is underway!

http://www.sustainlane.com/reviews/getting-the-most-from-human-waste/ICF8A2T14UAQ9HTV27Q8VLQXRTOI

Graphics: Jeremy Guest

http://www.myfoxtampabay.com/story/18612577/could-a-new-energy-source-start-right-here

Thank Youand Any

Question?

Costs

Wastewater reclamation system costs are a function of facility capacity, end-use option and treatment process configuration

Costs can be identified estimating:

- facility construction costs

- equipment purchases and

- operation and maintenance fees

Site development and electrical cost are assumed as 10 and 15 percent of the total facility costs respectively

Reclamation system’s annual cost is comprised of treatment and distribution facility personnel salaries, operating fees (recurring power and chemical cost) and maintenance cost (equipment repairs and replacements)

Personnel requirements are a function of facility size and complexity

Maintenance cost (spare parts, replacements) are estimated generally as a percentage of equipment first cost (e.g. 5 %)

For pipelines and storage tanks, maintenance costs are projected as two percent of capital costs

Costs