Treatment of waste water and industrial effluent

INTRODUCTION :• Waste water is the used water from any combination of domestic industrial, commercial or

agricultural activities.• Industriesusewater fora varietyof purposesuch as,‐ for manufacturinggoods.‐ for heating .‐ for coolig .‐ as a carrier of raw material.‐ as carrier of waste matter.‐ as a solvent.• The resulting water is then classified as a waste water .•Discharge of this untreated water in sewage system makes the task of treating domestic sewage a very difficult.

IMPORTANT CONTAMINANTS PRESENT IN WASTE WATER :• following contaminants which are present in waste water.1. Organic contaminants2.Inorganic contaminants 3.Biological contaminants 4.Radiological contaminants 5.Microbiology contaminants

1.Organic contaminants :• organic compound are those compound in which c atom is co –valently attached• in industerial waste water contain organic compound such as: benzene.• benzene is linked with to anemia and reduce the blood platelets and causes cancer.• the efficient method for removal of benzene is air stripping.

2. Inorganic contaminants:• inorganic contaminants include minerals like metals, heavy metals and metalloids.• N,O chemical like nitrites and nitrates are also present in the waste water in the form of inorganiccontaminants.•Ar is a metalloid of prime concern due to its widespread globally present in drinking water and harmful or injurious to health. They causes skin damage , circulatory problem and increase cancer risk.

3. Radiological contaminantes:

• In radiological contaminants thealpha or betaactivityareoccurs.

• On natural decayof radium the radon enter in drinking water .

• Theradon is the second leading causeof lung cancerafterthe smoking .

• Most efficient treated method is airstripping.

4. Microbial contaminants:

• Coliform bacteria is the one of the most concerning microbial contaminants. Which present in waste water indicate the presence of other pathogenic microbes.

• it is found in sewage water is leaked in water.

• Tubidity or lack of clearity , also can be indicated the presence of microbial contamination.

• The microbial contamination also causes the diarrhea, a major cause of death in the developing world .Typhoid , cholera, and dysentery wer common disease that is occur in contamination of microbes.

TREATMENT OF WASTE WATER1.PRELIMINARY TREATMENT

2. PRIMARY TREATMENT

3. SECONDARY TREATMENT

4. TERTIARY TREATMENT OR ADVANCE BIOLOGICAL OR CHEMICAL TREATMENT

1.PRELIMINARY TREATMENT :

• In preliminary treatment removal of waste water constituents such as: rags ,sticks , floatable guit, and grease that may cause maintenance or operational problem with the treatments operations.

• Preliminary treatment consists of followingunits .

‐ screening ― for removal of floating matter.

‐ grit chamber ― for removal of sand and guits.

‐ cominuters ― for grinding large size suspended solids.

‐ foatation units ― for removal of oil and grease.

‐ skimming tanks

‐ flow measuring units such as partial flame.

‐ Pumps

‐ Pre ― aeration units.

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2.PRIMARY TREATMENT :

• In primary treatment removal of suspended particle or organic matter from the waste water takes place.

• In primary treatment consists of followingprocesses/ units.

‐ Sedimentation ― primary settling tanks.

‐ Coagulation ― secondary settling tanks.

‐ Flocculation ― enhanced removal of suspended solids and organic matter from the waste water.

• Typically accompolished by chemical additio or filteration known as coagulation and flocculations.

2.SECONDARY TREATMENT:

• Secondary treatment process for waste water applications are following.

Aeration system

Biological treatment systems

Sludge and bio solids processing system

• Secondary treatment consists of following processes.

a) Activated sludge process

b) Oxidation ponds and lagoons

c) Trickling filter.

a) Activated sludge process :

• In activated sludge process the waste water containing organic matter is aerated with the help of aerobic microorganism in the aeration basin.

b) Oxidation ponds and lagoons :

• Oxidation ponds, also called lagoons or stabilization ponds, are large, shallow ponds designed to treat waste water through the interaction of sunlight bacteria and algae.

• Algae grow using energy from the sun and carbon di oxide and inorganiccompounds released by bacteria inwater.

c) Trickling filter :

• It is also known as percolating filteror sprinkling filters.

• Trickling filter are used for biological treatment of industerial waste whichare ammenable to aerobic biological processes.

• A trickling filter or bio filter consists of a basin or tower filled with supportmedia such as , stone plastic shapes orwooden slats.

3. TERTIARY TREATMENT:

• In tertiary treatment is removal of suspended solids (after secodary treatment). Usually by granular media filteration or micro screens.

• Nutrient removal is often in the tertiary treatment.

TERTIARY TREATMENT

PROCESS APPLICATION

Chlorination / ozonation UV For destruction of pathogen and chemical oxidation of organic matter.

Filteration (media, micro, media)

For removal of suspended solids ,oil and and organics.

Reverse osmosis Recovery of water forreuse.

evaporation To reduce volume / zero discharge

Post aeration To increase the dissolved oxygen conc.is treatedwaste water before discharge to river/sea.

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