Wastewater Treatment by Sumona Mukherjee

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Wastewater Treatment

Technologies

Sumona MukherjeePhD Student


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Introduction

It is unhealthy for humans, pets, and wildlife to drink or come in contact withsurface or ground water contaminated with wastewater.

Inadequate treatment of wastewater allows bacteria, viruses, and other disease-

causing pathogens to enter groundwater and surface water.

Hepatitis, dysentery, and other diseases may result from bacteria and viruses indrinking water.

Disease-causing organisms may make lakes or streams unsafe for recreation. Flies

and mosquitoes that are attracted to and breed in wet areas where wastewater

reaches the surface may also spread disease.


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Wastewater is the combination of liquid and water-transported wastes from homes,

commercial buildings, industrial facilities, and institutions, along with any groundwater

infiltration and surface water and stormwater inflow that may enter the sewer system.

Point sources of wastewater are discrete and identifiable sources that are divided into

domestic and industrial sources.

Domestic sources include residences and small businesses. Compared with industry, these

are relatively small sources. As a result, a major issue in this category is the collection of

wastewater (i.e., it is a major expense when added up for the entire community)Industrial sources are relatively large sources that include such sub-categories as the

chemical, pharmaceutical, oil, mining, and metal industries. Because of their size, these

sources are generally easier to collect, but harder to treat (e.g., their chemical content can

vary tremendously).

Introduction

Source of Wastewater


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Source of Wastewater

Non-point sourcesare diffuse and generally occur from water runoff. Because they are

spread over large areas, they tend to be more difficult to control, and in recent years they

have gained greater attention from legislators. They are divided into agricultural, urban, andatmospheric sources.

Agricultural sources include farms, which can contribute fertilizers, pesticides, soil erosion,

and plant and animal wastes to water runoff. Collectively, they usually constitute the largest

source of pollutants to water, and the erosion contributions are being worsened by the

deforestation occurring in various parts of the world.

Urban sources include the storm water systems that collect water from the gutters of streetsin towns and cities. The true scope of the problem from urban sources is still not very well

understood, but it is clearly a major contributor.

Atmospheric sources include air pollution's contribution during precipitation (e.g., acid rain).

We do not discuss it in detail here because we have already covered it in a previous section.

Nevertheless, it is a classic example of the multi-media role of wastewater pollution.


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Selection of wastewatertreatment options

The selection and design of treatment facilities is based on a study of

the physical, chemical and biological characteristics

of the wastewater

the quality that must be maintained in the

environment to which the wastewater is to be

discharged or for the reuse of the wastewater

the applicable environmental standards or dischargerequirements that must be met


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Characteristics of wastewater


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Contaminants of concern in wastewater treatment

Contaminants Reason for concern

Suspended solids Sludge deposits and anaerobic conditionsBiodegradable

organics

Depletion of natural oxygen resources and the

development of septic conditions

Dissolved organics Inorganic conditions added by usage.

Reclamation and reuse application.

Heavy metals Metallic constituents added by usage.

Many metals are also classified as priority pollutants

Nutrients Growth of undesirable aquatic life; eutrophications

Pathogens Communicable

Priority organicpollutnts

Suspected carcinogenicity, mutagenicity,teratogenicity, or high acute toxocity.

Many priority pollutants resists conventional treatment

methods (known as refractory organics)


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Organic Waste

COHNS

End Products

New Cell Tissue

C5H7NO2

Oxidation

Synthesis

energy

energy

O2

Stable organic

end product

O2

O2

Endogenous respiration

Schematic diagram of the aerobic biological conversion of organic matter in wastewater to end

products, to new cells and ultimately to stable organic and other end products


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A:

B:

(to be written)


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Typical composition of untreated domestic wastewater


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Unit waste loading factors


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Minimum national standards for secondary treatment


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Typical flow diagram for the treatment of domestic wastewater


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Levels of wastewater treatment


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Application of physical unit operations of wastewater treatment

Ci i


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Circular comminutor


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S i D i d f th l f lid


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Screening Devices used for the removal of solids

D i d f i i f h i l i t t


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Devices used for mixing of chemicals in wastewater

D i d f t f f i t th t t


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Devices used for transfer of oxygen into the wastewater

D i d f di t ti f t t


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Devices used for sedimentation of wastewater



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Typical horizontal-lamp parallel-flow ultraviolet (UV) facility used for the

inactivation of microorganisms

Applications of Chemical unit process in wastewater treatment


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Applications of Chemical unit process in wastewater treatment

Major biological treatment processes used for the wastewater treatment


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Major biological treatment processes used for the wastewater treatment

Typical design parameters used the activated sludge processes


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Trickling Filters


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Trickling Filters

Typical design parameters for various types of trickling filters


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Typical design parameters for various types of trickling filters

Rotating Biological Contractor


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Rotating Biological Contractor

Typical design parameters for the various types of trickling filters


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Typical design parameters for the various types of trickling filters

Pond system for the treatment of wastewater


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Pond system for the treatment of wastewater

Land application of wastewater


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Land application of wastewater

Typical flow diagrams for the removal of nutrients from wastewater


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yp c ow d g s o e e ov o u e s o w s ew e

Filtration system for wastewater reclamation system


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y y

Sludge processing methods


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g p g

Sludge processing methods


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g p g


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Typical two stage sludge digestion facility


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yp g g g y

Advanced treatment processes used to purify treated water


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Thank You

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Wastewater Treatment by Sumona Mukherjee