Waste WaterTreatment

8/2/2019 Waste WaterTreatment

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For Waste Water Treatment

Presented

By

Sandeep B

Koushik G


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Sanitary sewage Commercial wastes

Surface runoff Agricultural wastes

Industrial effluents

Various types ofWaste Waters


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Effects Of These Waste Water

Decaying organic matter and debris can useup the dissolved oxygen. In a lake so fish and other aquatic biota

cannot survive excessive nutrients, such asphosphorus and nitrogen (including ammonia),can cause eutrophication. Bacteria, viruses and disease-causingpathogens can pollute beaches and

contaminate shellfish populations. Leading to, cadmium, chromium and arseniccan have acute and chronic toxic effects onspecies.


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What is Wet Land? A constructed wetland or wetpark is an artificial wetland,marsh or swamp created as anew or restored habitat for nativeand migratory wildlife, foranthropogenic discharge such as

Wastewater Storm water runoff Sewage treatment Land reclamation after mining,

refineries,


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Classification of Wet LandsConstructed wetlands are classified according to the water

flow regime

Free water surface flow (FWS CWs) or

Subsurface flow CWs.

Based on the flow of water in the SF CWs.

They are again classified into Horizontal Flow Beds (HFB)

Vertical Flow Beds (VFB)


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Free Surface CW

Horizontal Surface CW

Vertical Surface CW


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Horizontal Flow Bed

Inlet

HFB HFB near PortugalOutlet


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Design Specifications

The depth of filter beds is normally around 60 cm with an

additional 15 cm freeboard for water accumulation.

The required specific surface area is about3-10 m/p.e. depending on temperature and other factors.

The organic loading per surface area should not exceed

4-10 g BOD/ (m) in cold climates

16 g COD/ (m) in warm climates.The hydraulic loading should be 60-80 mm/d for grey

water and 40 mm/d for wastewater.


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Vertical Flow Bed

Inlet

Outlet

Vertical Flow Beds


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Design Specifications

The depth of the sand filter beds should be atleast 50 cm, with an additional 20 cm of gravel at

the base to cover the drainage pipes.

The required specific surface area is usually

3-4 m/p.e. in cold regions.

The organic loading per surface area should belimited to 20 gCOD / (md) in cold climates).


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Pre TreatmentPre-treatment removes materials that can be easily

collected from the raw waste water before they

damage or clog the pumps.

Screening Grit Removal


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Primary Treatment: In the primary sedimentation stage, sewage flows through large tanks,commonly called "pre-settling basins", "primary sedimentation tanks" o

"primary clarifiers.

The dimensions of the tank should be designed to effect removal of a

high percentage of the floatables and sludge.A typical sedimentation tank may

remove from 50 to 70 percent of

suspended solids.

30 to 35 percent of biochemical

oxygen demand (BOD) from the

sewage.


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Vegetation in a wetland provides a substrate (roots, stems,

and leaves) upon which micro organisms can grow as they

break down organic materials.

This community of microorganisms is known as

the periphyton. The periphyton and natural chemical processes

are responsible for approximately 90 percent

of pollutant removal and waste breakdown.

Bio Filtration


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Plants Chosen:MacropytesThey produce oxygen, and act as food for some fish and

wildlife.

Although the majority of constructed wetland designershave long relied principally on Typhas and Phragmites.

Eichhornia crassipes


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General Contaminants Removal: Physical, chemical, and biological processes combine in wetlands to

remove contaminants from wastewater.

Theoretically, wastewater treatment within a constructed wetland

occurs as it passes through the wetland medium and the plants

rhizosphere.Rhizosphere is a thin film around each root hair is aerobic due to the

leakage of oxygen from the rhizomes, roots, and rootlets.


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Specific Contaminants Removal:Nitrogen Removal :The biological transformation of organically combined nitrogen toammonium nitrogen during organic matter degradation byammonifaction process.

Ammonia removal :The formation of ammonia (NH3) occurs via the mineralization orammonification of organic matter under either anaerobic oraerobic conditions.

This ion forms when ammonia combines with water as follows:

Ammonifiaction:

NH3 + H2O (NH4+) + OH


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The Nitrite is oxidized to nitrate (NO). The overall nitrificationreactions are as follows:Nitrification:(1) 2(NH4+) + 3O2 4H+ + 2H2O + 2NO(2) 2NO + O2 2NO


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Phosphorus Removal:

It occurs naturally in both organic and inorganic forms.1. The binding of phosphorus in organic matter as a result of

incorporation into living biomass,

2. Precipitation of insoluble phosphates with ferric iron, calcium, and

aluminum found in wetland soils.


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BOD and COD removal: Bio Oxygen Demand (96.2 % removal) Chemical Oxygen Demand (93.8% removal)


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Applications:1. Municipal wastewater treatment2. Treatment of household wastewater or grey water3. Tertiary treatment of effluents from conventional wastewatertreatment plants

4. Industrial wastewater treatment such as landfill leachate,petroleum refinery wastes, acid mine drainage, agriculturalwastes, effluent from pulp and paper mills, textile mills.5. Sludge dewatering and mineralization of fecal sludge or sludgefrom settling tanks.6. Storm water treatment and temporary storage7. Treatment of water from swimming pools without chlorine.


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Stop Pollution

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