Treatments of sewage, sludge and polluted water

in this presentation describe what is sewage, sludge and polluted water and also the treatment of sewage, sludge and water pollution.

1. Mobeen Arshad Roll no 20 MSc 4 th Semester GC Women University, Sialkot Treatments of sewage, sludge and polluted water

2. Contents Sewage What is sewage treatment? Process of sewage treatment Sludge Sludge treatment process Polluted water Polluted water treatment

3. Sewage Produced by a community of people Characterized by volume or rate of flow, physical condition, chemical and toxic constituents,  Bacteriologic status (which organisms it contains and in what quantities) consists mostly of grey water, black water, detergents, soaps and toilet paper.

4. What is sewage Treatment? Process of converting sewage water that is no longer needed or is no longer suitable for use into bilge water that can be discharged back into the environment Sewage water Bilge water (back into environment)

5. PROCESS OF SEWAGE TREATMENT SCREENING removes large objects like, diapers, nappies, sanitary items, cotton buds, face wipes and even broken bottles, bottle tops, plastics and rags that may block or damage equipment.  Special equipment is used to remove grit that gets washed into the sewer. PRIMARY TREATMENT separation of organic solid matter (or human waste) from the wastewater putting the wastewater into large settlement tanks for the solids to sink to the bottom of the tank

6. PROCESS OF SEWAGE TREATMENT At bottom, large scrappers continuously scrape the floor of the tank and push the sludge towards the center. SECONDARY TREATMENT Put water into large rectangular tanks. called aeration lanes. Air pumped into the water to encourage bacteria to break down the tiny bits of sludge that escaped the sludge scrapping process.

7. PROCESS OF SEWAGE TREATMENT FINAL TREATMENT treated wastewater is passed through a settlement tank Sludge formed at the bottom of the tank from the settling of the bacteria action Again sludge scrapped and collected Free from any harmful substances Than filtered with a bad of sand

8. PROCESS OF SEWAGE TREATMENT

9. SLUDGE Semi-solid slurry that can be produced from a range of industrial processes, from water treatment, wastewater treatment or on site sanitation systems Settled suspension obtained from conventional drinking water treatment Solids separated from suspension in a liquid

10. Sludge treatment Process Stabilization Also called mass reduction or degistion Result in reduction of organic content Improved drain ability Reduces odor of the polluted matter Reduce the volume of sludge Two units Anaerobic aerobic

11. Sludge treatment Process Aerobic digestion Organic part decomposes in the presence of oxygen by micro organism. Bacteria convert organic matter into carbon dioxide. Advantage Operation is relatively easy Lower capital cost Lower BOD concentrations in supernatant liquor End product odorless and stable

12. Sludge treatment Process Disadvantage A high power cost is associated with supplying the required O2 A digested sludge is produced with poor mechanical dewatering characteristics A useful by-product such as methane is not recovered

13. Sludge treatment Process Anaerobic digestion A biological process that uses bacteria in an oxygen free environment. These bacteria converts volatile solids into carbon dioxide, methane and ammonia. Sludge held without aeration for 10-90 days Process can be accelerated by heating to 35-40oC These are called High Rate Digesters (10-20 days)

14. Sludge treatment Process Advantages low solids production useable methane gas produced Disadvantages high capital costs susceptibility to shocks and overloads

15. Sludge treatment Process Sludge dewatering Dewatering aims to reduce the water content further. The sludge can then be handled like a solid. Dewatering can be done mechanically using a filter press (employing pressure or vacuum), or a centrifuge. Also be done using drying beds.

16. Sludge treatment Process Drying beds Most popular methods. A drying bed consists of a 30 cm bed of sand with an under-drainage . Sludge is applied on the sand bed and is allowed to dry by evaporation and drainage of excess water over a period of several weeks depending on climatic conditions. Bacterial decomposition of the sludge takes place during the drying process while moisture content is sufficiently high. During the rainy season the process may take a longer time to complete

17. Sludge treatment Process

18. POLLUTED WATER Water pollution is the contamination of water bodies (like oceans, seas, lakes, rivers, aquifers and groundwater) usually caused due to human activities. Water pollution is any change in the physical, chemical or biological properties of water that will have a detrimental consequence any living organism.

19. POLLUTED WATER TREATMENT PROCESS Industrial water treatment Primary phase Suspended, solid particles and inorganic material is removed by the use of filters Secondary phase Use biological filters to naturally degrade the organic waste material Tertiary phase All solid particles remove and chemical additives are supplied to get rid of any left-over impurities

20. POLLUTED WATER TREATMENT PROCESS De-nitrification Prevent leaching of nitrates in soil Fertilizers contain nitrogen, bacteria in the soil convert the nitrogen in the fertilizer to nitrates, make easier for plants to absorb Immobilization is a process where the nitrates become part of the soil organic matter Oxygen levels low, another form of bacteria then turns the nitrates into gases such as nitrogen, nitrous oxide and nitrogen dioxide This conversation process called de-nitrification.

21. POLLUTED WATER TREATMENT PROCESS Septic tanks and sewage treatment Septic tanks treat sewage at the place where it is located Used to treat sewage from an individual building Untreated sewage from a property flows into the septic tank Solids are separated from the liquid, depending on their density Heavier particles settle at the bottom of the tank whereas lighter particles at the top. Biological process use to degrade solid particles, than liquid flow in land drainage and solid filttered .

22. POLLUTED WATER TREATMENT PROCESS Ozone wastewater treatment Ozone generator is used to break down pollutants in the water source Generators convert oxygen into ozone by using ultraviolet radiation or by an electric discharge field Ozone is a very reactive gas that can oxidise bacteria, moulds, organic material and other pollutants found in water

23. POLLUTED WATER TREATMENT PROCESS Ozone wastewater treatment benefits: Kills bacteria effectively Oxidises substances such as iron and sulphur so that they can be filtered out of the solution no nasty odours or residues produced from the treatment Ozone converts back into oxygen quickly, and leaves no trace once it has been used.

24. POLLUTED WATER TREATMENT PROCESS Ozone wastewater treatment disadvantage: The treatment requires energy in the form of electricity; this can cost money and cannot work when the power is lost. Treatment cannot remove dissolved minerals and salts. Produce by-products such as bromate that can harm human health.