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Effluent discharge system and struct

ShikSurMan

Raja

Practical Assignment No 02

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Introduction Effluent is defined by the United States Environmental

Protection Agencyas wastewater - treated or untreated flows out of a treatment plant, sewer, or industrial outfall

Effluent and effluent discharge is becoming more and moimportant as pollution is becoming critical and global issu

We all are the stake holders in it

http://en.wikipedia.org/wiki/United_States_Environmental_Protection_Agencyhttp://en.wikipedia.org/wiki/United_States_Environmental_Protection_Agencyhttp://en.wikipedia.org/wiki/United_States_Environmental_Protection_Agencyhttp://en.wikipedia.org/wiki/United_States_Environmental_Protection_Agency

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waterIndustrial/domestic Waste water/

effluent

TRE

ATMEN

T

Secondaryeffluent

primary

secondary

Tertiary

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Primary treatment

The objective of primary treatment is the removal of settleable and inorganic solids by sedimentation, and the removal of matethat will float (scum) by skimming.

Approximately 25 to 50% of the incoming biochemical oxygen d(BOD5), 50 to 70% of the total suspended solids (SS), and 65% oand grease are removed during primary treatment.

Some organic nitrogen, organic phosphorus, and heavy metalsassociated with solids are also removed during primary sedimebut colloidal and dissolved constituents are not affected.

The effluent from primary sedimentation units is referred to aprimary effluent.

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Secondary treatment

The objective of secondary treatment is the further treatmthe effluent from primary treatment to remove the residuaorganics and suspended solids.

involves the removal of biodegradable dissolved and colloiorganic matter using aerobic biological treatment processe

Aerobic biological treatment is performed in the presenceoxygen by aerobic microorganisms (principally bacteria) thmetabolize the organic matter in the wastewater

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The proper disposal of treatment plant effluent or reuserequirements is an essential part of planning and designiwastewater treatment facilities. Different methods of ultidisposal of secondary effluents are discussed as follows.Natural EvaporationGroundwater RechargeIrrigationRecreational LakesAquacultureMunicipal UsesIndustrial UsesDischarge into Natural Waters

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Natural evaporation

process involves large impoundments with no discharge . Depending on the climatic conditions large impoundmen

be necessary

considerations must be given to net evaporation, storagerequirements, and possible percolation and groundwaterpollution

method is particularly beneficial where recovery of residudesirable such as for disposal of brines.

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Ground water recharge

Methods for groundwater recharge includerapid infiltration

intermittent percolation

and direct injection

In all cases risks for groundwater pollution exists.

Furthermore, direct injection implies high costs of treatineffluent and injection facilities.

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Irrigation

Irrigation has been practiced primarily as a substitute fornatural waters or sparse rainfall in arid areas.

In most cases food chain crops (i.e. crops consumed by huand those animals whose products are consumed by humamay not be irrigated by effluent.

However, field crops such as cotton, sugar beets, and cropseed production are grown with wastewater effluent.

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Recreational lakes

The effluent from the secondary treatment facility is storelagoon for approximately 30 days.

The effluent from the lagoon is chlorinated and then percthrough an area of sand and gravel, through which it travapproximately 0.5 km and is collected in an interceptor tre

It is discharged into a series of lakes used for swimming,boating and fishing.

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Aquaculture

Aquaculture, or the production of aquatic organisms (bothand fauna), has been practiced for centuries primarily forproduction of food, fiber and fertilizer.

Lagoons are used for aquaculture, although artificial andnatural wetlands are also being considered.

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Municipal uses

Technology is now available to treat wastewater to the extthat it will meet drinking water quality standards.

However, direct reuse of treated wastewater is practicablon an emergency basis.

Many natural bodies of water that are used for municipalsupply are also used for effluent disposal which is done tosupplement the natural water resources by reusing the effmany times before it finally flows to the sea.

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Industrial uses

Effluent has been successfully used as a cooling water or bfeed water.

Deciding factors for effluent reuse by the industry includeavailability of natural water

quality and quantity of effluent, and cost of processing

pumping and transport cost of effluent

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Discharging in Natural waters

Discharge into natural waters is the most common disposapractice.

The self-purification or assimilative capacity of natural wathus utilized to provide the remaining treatment

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On-site waste disposal septic tank receives wastewater g

house and traps the solids, allowinto exit through the tank outlet pip

As wastewater enters, the same atank by hydraulic displacement, flthe drain-field

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Zero liquid discharge system

Modern and recent concept Minimize water release

Maximize reuse and recycling

In aqua gaining importanceBiosecure system

Check disease outbresk Major issue in shrimp units

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