advance methods in waste water management
TRANSCRIPT
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