Wastewater types and treatment

Wastewater and its treatment

1. Wastewater Treatment Aqsa

2. “ Thousands have  lived without love ,  not  one   without water ” “Auden”

3. Wastewater Water that has been affected or contaminated by human activities in any way. It includes substances such as human waste, food scraps, oils, soaps and chemicals. Different sources. Domestic and nondomestic

4. Types of Wastewater

5. Wastewater composition Organic matter Heavy metal Nutrient Pathogen Sand Suspended Solid Salt Stone

6. Wastewater constituents Organic matter 1. Sugar 2. Protein 3. Fat

7. Suspended matter in sewage Food left over 2. Sand particles 3. Fecal matter

8. Waste water composition

9. Impact of untreated sewage discharge

10. Purpose

11. General steps in Wastewater Treatment

12. Overview of Wastewater Treatment

13. Steps of Wastewater treatment 1. Collection of water 2. Preliminary Treatment 3. Primary treatment 4. Secondary Treatment 5. Tertiary Treatment 6. Sludge Treatment 7. Discharge

14. Preliminary Treatment Physical Treatment and clarification of large particles. Screening Grit chamber

15. Primary Treatment Physical separation of small particle Settlement tank Gravitational force & Prevent damage 25-50%BOD 50-70%Suspended solids 65% oil and grease Sludge and scum

16. Secondary Treatment Mainly liquid part Biological treatment Remove organic matter Aeration chamber & secondary clarifier Activated Sludge

17. ii. Trickling Filter

18. Tertiary treatment Chemical treatment Kill microbes Gravity filters and membranes Chlorination

19. Advance treatment

20. Treatment overview Functional units Physical treatment • Chemical treatment • Biological treatment Targeting specific groups of pollutants

21. Physical methods

22. Screening First step Removal of floating solids Rags, paper, plastic Prevent damage and blockage Coarse screening and fine screening

23. Grit chamber Is long narrow or circular tank Remove sand, eggshell, coffee ground Putrescible material Prevent channel clogging And pump damage

24. Fat and grease removers Passing sewage small tank Fat collected through skimmers

25. Sedimentation R emoves particles by gravity. Accumulated solids, or sludge. Removed periodically from bottom. Coagulants are added to the Aid in settling.

26. Adsorption Remove compounds from industrial wastewater. Removal or low concentrations of non-degradable organic compounds Adsorption takes place when molecules in a liquid bind themselves to the surface of a solid substance. Active carbon is by far the most commonly used adsorbent.

27. Chemical methods

28. Neutralization Industrial water Adjust the pH value Treat waste water containing metals Acid+ Base= Neutralization. Collection.

29. Flocculants and coagulants Solid removal, water clarification, lime softening , sludge thickening, and solid dewatering. Neutralization Inorganic or organic coagulant Used to treat water for suspended solids removal. .

30. Contd…. 1.Flocculants i . Gather destabilize particles together ii. agglomerate and iii. drop out of solution 2. Low, medium and high weight molecular polymers

31. Oxidation Oxidation reduces the BOD of waste water Reduce the toxicity. Widely used for disinfection.

32. Ion exchange Use to soften hard water Calcium and magnesium Sodium ions Dissolved sodium chloride salt, or brine Exchange of ions

33. Ozonation Disinfection of drinking water Removal of effluents from wastewater treatment plant is a process called ozonation Degradation of organic and inorganic pollutants.

34. Disinfection Reduce the number of microorganisms For the later use. Depends on The quality of water treated Type of disinfectant used Disinfectant dosage

35. Biological methods

36. Aerobic Treatment Biological process Presence of oxygen. Rapid & most efficient Remove up to 98% of organic contaminants. . Remain efficient and stable in all conditions.

37. Types of aerobic treatment

38. i . Activated Sludge Process  A multi-chamber reactor unit Use of highly concentrated microorganisms Degrade organics and remove nutrients.

39. ii. Trickling filters Second commonly using type. Percolating or sprinkling filters Remove compounds such as ammonia

40. iii. Aerated Lagoons A treatment pond Provided with mechanical aeration To promote the biological oxidation. The effluent may be reused Settled sludge requires a further treatment.

41. iv. Oxidation Pond Involve an interaction between bacteria, algae and other organisms Feed on the organic matter from primary effluent. Productive Slow and requires large areas of land.

42. Anaerobic Treatment Effectively treat high strength waste water Employs organisms that function in the absence of oxygen Sludge degradation and stabilization. Converts about 40% to 60% of the organic solids to methane (CH4) and carbon dioxide (CO2).

43. Wastewater treatment system in Pakistan Only 1% of the domestic and industrial wastewater receives treatment. City Waste water plants Islamabad Three wastewater treatment plants, only one functional Lahore some screening and grit removal systems, but they are hardly functional Karachi Two trickling filters, effluents generally receive screening and sedimentation Faisalabad There is a wastewater treatment plant, in which wastewater receives primary treatment. Rural areas Nonexistent