3. Water quality affected by some anthropogenic influence. Origin - domestic, industrial & commercial or agricultural activities.

4. Physical Characteristics Color Odor Turbidity Wastewater Characteristics

5. Chemical Characteristics Biological oxygen demand (BOD) Chemical oxygen demand (COD) Metals Dissolved gases pH (organic, inorganic, suspended, and dissolved solids)

6. Biological Characteristics Bacteria Viruses Worms

7. Is a process to treat wastewater in order to:  To remove adverse effluents.  Make it a part of water cycle with less environment toxicity issues.  Make it fit for reuse.

8.  Recycling  Use for Agriculture - Pakistan  Tertiary treatment -Drinkable water in Japan and Netherland

9.  Primary Treatment ( Mechanical Treatment)  Secondary Treatment ( Biological Treatment)  Tertiary Treatment ( Chemical Treatment)

10. It is the initial step which involves following steps: Preliminary Treatment.  Screening.  Grit Chamber.  Sedimentation.

11.  To separate and remove large matter which might negatively affect the efficiency of later treatment procedures

12.  Grit chambers are to remove the inorganic particles like stones, sand etc

13.  Is a physical water treatment process using gravity to remove suspended solids from water.

14. It is the second process in which 90% of organic matter remove by microbial activity. Types:  Lagoons  Trickling Filter  Activated Sludge

15.  An lagoon or aerated basin is a holding and/or treatment pond provided with artificial aeration to promote the biological oxidation of wastewaters.

16.  A trickling filter has inert materials like rocks, gravel, slag, etc. over which the wastewater flows  Bio-film is formed  Wastewater sprayed over the inert material having microbes which decompose the waste matter in water

17.  In activated sludge sewage is treated using air and microbes composed of bacteria and protozoa.

18.  It involves chemical process for pollutants which are left after primary and secondary treatment.  Extremely costly.

19. ◦ Processes: Bleaching to remove coloration Disinfection to kill pathogens Coagulation-sedimentation with alum Adsorption using activated charcoal Electro-dialysis for salt removal Nitrogen Control Biological Phosphorus Control Carbon Adsorption

21. Sludge Disposal:  Landfills  Incineration  Land application

22.  Maintenance of clean water for reuse  New research and improvement in water quality  Disease control  Economic benefits(jobs are created)

23.  Active sludge can be used as a natural fertilizer  Ground and surface water safe from pollution  Water can be used to irrigate fields  Cost of transport of polluted water saved