Advance Methods in Waste Water Management

Submitted by,

Sujindran. BVicknesh. K

Water circulates through the land just as it does through the human body, transporting, dissolving, replenishing nutrients and organic matter.

SurvivalCookingBathingWashing

Necessity for Water Treatment• To provide desired quality of water• To provide and maintain hygienically

safe water• Removal of hardness, dissolved

gases, odours etc..,• Eliminating tuberculative and

corrosive nature of water

Purification process in public water supplies

• Screening• Sedimentation• Filtration• Disinfection• Aeration• Softening• Miscellaneous treatments

Unit Operation

Changes formed are»Physical»Chemical»Biological

Important Unit Operations

•Gas Transfer•Ion Transfer•Solute Stabilization•Solid Transfer•Miscellaneous Operations•Solid Concentration and Stabilization

Chemical CoagulationChemicals Used

Aluminum sulphate (alum) Polyaluminium chloride (Liquid

alum)Alum potashIron salts (Ferric sulphate or

Ferric chloride)Particles that cause turbidity (e.g. silt, clay) are generally negatively charged, making it difficult for them to clump together because of electrostatic repulsion. But coagulant particles are positively charged, and they chemically attracted to the negative turbidity particles. With mixing the neutralized particles then accumulate to form larger particles which settle faster.

Super Chlorination• Super chlorination is a process in which the

chlorine level in water is raised to abnormally high levels over a very short period of time.

• Over time and with extended use, organic wastes build up in pool water. These include body oils/sweat, other body fluids and suntan lotions.

• Generally, one gallon of liquid chlorine is needed for every 10,000 gallons of pool water.

• Super chlorination is used in heavily polluted water, as well as in the orthotolidine test and orthotolidine arsenide test.

Centrifugation Centrifugation is a separation process

which uses the action of centrifugal force to promote accelerated settling of particles in a solid-liquid mixture. Phases formed in the vessel during centrifugation are,

• The Sediment - The flocs• The Centrate - The supernatant

water

1. Cylindroconical bowl2. Helical extraction screw (scroll)3. Feed4. Distributor5. Ring space6. Settled product7. Liquid level8. Drying zone9. Clarified liquid10. Adjustable thresholds

Centrifugation

Incineration• Incineration of waste materials converts the

waste into ash, flue gas and heat• The ash is mostly formed by

the inorganic constituents of the waste, and may form particulates carried by the flue gas.

• The flue gases must be cleaned of gaseous and particulate pollutants before they are dispersed into the atmosphere.

• In some cases, the heat generated by incineration can be used to generate electric power

The Spittelau incineration

plant in Vienna, Austri

a, designed by Friedensrei

ch Hundertwasse

r.

Thermal Desalination The thermal

desalination process uses energy to evaporate water and subsequently condense it again. When there is waste heat or sufficient electricity available, as is often the case with refineries and power plants, thermal desalination is an efficient and viable solution

Recarbonation• A process in which carbon dioxide is

bubbled into the water being treated to lower the pH. The pH may also be lowered by the addition of acid. Recarbonation is the final stage in the lime–soda ash softening process. This process converts carbonate ions to bicarbonate ions and stabilizes the solution against the precipitation of carbonate compounds

Process