Industrial effluents and Wastewater Treatment

Industrial Effluents and Waste water treatment

1. Industrial Effluents and Wastewater Treatment Naveera khan Muhammad Ibrahim Areesha Fareed Shifa Tariq L1F17BSBT0055 L1F17BSBT0058 L1F17BSBT0075 L1F17BSBT0079 Group # 7

2. Contents: Effluents Industrial Effluents Types of Industries Food Industry Organic Chemical Industry Iron and Steel Industry Offshore Drilling Effects of Offshore Drilling Drilling fluids Oil spills or Leaks Other effects of Offshore Drilling Waste water Treatment Primary Treatment or Mechanical Treatment Physical Treatment Screen Chamber Grit Chamber Floatation or skimming tank Chemical Treatment Sédimentation Coagulation Filtration Floculation Secondary Treatment or Biological Treatment Aerobic Treatment Activated Sludge Process Trickling Filter Anaerobic Treatment Oxygen Pond Tertiary Treatment or Advance Biological or Chemical Treatment Precipitation Nitrogen Stripping Chlorination Other advanced methods Ultraviolet Light Ozone Sludge Processing Anaerobic Digester Sludge Dewatering and Drying Conclusion References

3. Effluents: Effluent is an outflowing of water or gas to a natural body of water, from a structure such as a wastewater treatment plant, sewer pipe, or industrial outfall. Effluent, in engineering, is the stream exiting a chemical reactor.

4. Industrial Effluents

5. It is caused by emission of industrial waste (effluent) into water bodies. It is the main source of water pollution. Industrial waste includes organic pollutants and toxic chemical that is heavy metals, acid and alkalis, Oils, lubricant, petroleum and grease Pollutants Industrial Source Impact of Industrial Waste Heavy Metals Lead Mercury Paint Industry Smelting Chemical Industry Lead inhibit action of bodily enzyme Mercury transforms inti water soluble methylmercury by bacterial action and thus contaminates fish Acids Sulphuric Acid Mine Drainage Acid cause corrosion of metal and concrete Alkalies Textile and paper industries Alkalies in industrial waste affects aquatic life. Oil Oil refineries Oil waste is harmful for fish and marine birds. Petrochemical Petroleum plants Petrochemical are toxic to marine life

6. Types of Industries: Following are some major types of industries responsible for industrial effluents Food industry Organic chemical industry Iron and steel industry Offshore drilling

7. 1. Food Industry: Vegetable washing—generate waste water with—increased particulate matter Animal processing – generate waste water with—added antibiotics, pesticides 2. Organic Chemical Industry: These industries manufacture or use, complex organic chemicals which includes pesticides, paints, detergents, plastics etc

8. 3. Iron and steel industry: Conservation of iron to steel, contaminates waste water with—hydraulic oils. 4. Offshore Drilling: Offshore drilling involves exploring of oil and gas beneath the ocean floor.

9. Effects of Offshore Drilling: Drilling fluid: Drilling mud or fluid is pumped into the well during drilling to cool, lubricate and regulate the pressure while drilling. Residual drilling is claimed to be toxic and contains heavy metals and petroleum products of various concentrations. Impact of drilling fluid- it affects the health and reproduction of marine animals Oil spills or leaks: It is the leakage of oil and petroleum products into sea water due to accidents of ships and oil takers or leakages of pipelines or storage tanks. They occur when oil is produced—from offshore well and stored temporarily or may also happen during transportation by pipes or tankers.

10. Other effects of Offshore Drilling: Damage caused by oil spills-on marine organisms such as fishes, reptiles, amphibians and birds that live in or near the ocean are badly effected by oil wastes which may contain volatile organic compounds. Oil spills deteriorate thermal insulation and damages reproductive system. Gill of fish get coated with oil leading to their death. It interrupts the food chain, which may cause extinction of species. It penetrates bird’s feathers and effects its buoyancy. Oil spreads on water surface and thus reduces the amount of oxygen in water. On reaching coast it harms coastal marine life.

11. Wastewater Treatment

12. When effluent discharged into a river body such as lake, river or sea a number of process occur like physical, chemical and biological characteristics of water change which cause loss of organism. Non bio-degradable pollutant like mercury are most deadly as they accumulate in aquatic organism which lead to Bio magnifications. The treatment procedure are generally divided into four steps: Primary Treatment or Mechanical Treatment Secondary Treatment or Biological Treatment Tertiary Treatment or Advance Biological or Chemical Treatment Sludge Processing

13. I. Primary Treatment or Mechanical Treatment: A mechanical way to treat effluents. Suspended solids and floating materials are removed. Some methods of physical filtration are: Physical treatment. Screen Chamber Grit Chamber Floatation or skimming tank Chemical treatment. Sédimentation Coagulation Filtration Floculation

14. 1. Physical Treatment: Screen Chamber: Screen chamber remove dead animals, branches of tree, logs of wood, rags and other coarse floating material. The effluent is passed through the bar screens for rag removal. In this section, two automatic bar screen cleaners remove large solids (rags, plastics, etc.) from the raw sewage. The collected material is placed in dumpsters to be taken later to the landfill. B. Grit Chamber: Grit include sand, ash, egg shell etc. Of diameter less than 0.2 mm. Next, the effluent moves to the grit tanks. These tanks reduce the velocity of the effluent so that heavy particles may fall to the bottom. The solids are pumped to an auger pump which separates the water from the grit while the water moves onward. The grit (mostly inorganic solids) goes to a dumpster which is taken to a landfill. There are two complete grit removal systems which are rotated in operation for equal hours. C. Skimming Tank: Fats, waxes, fatty acid, soap, minerals and vegetable oil present in waste water are collectively called as oil and grease. As oil and grease are lighter than water they are normally separated by natural flotation. The bubbles of air are passed on the bottom of the tank and floating matter rises and remain on the surface of waste water which can be separated easily.

15. 2. Chemical Treatment: Sedimentation: Settling down of suspended particles at the bottom of water is called Sedimentation.. In this process water is collected into big pond, slowly- slowly impurities are settled down by gravitation. The main objective of Sedimentation are: The suspended and colloidal impurities are separated in sedimentation tank by gravitation. The main principle of sedimentation is to allow water to rest or flow at a very slow velocity. The process of settling of particles depend mainly on velocity of flow, size, shape and specific gravity of particles and viscosity of liquid. B. Coagulation: Colloidal particles which are fine particles of size finer than 0.0001 mm carry electric charges on them. The turbidity in water is mainly due to the presence of very fine particles of clay, silt and organic matter. Coagulation is the process in which certain chemical agent is mixed with water then colloidal and suspended particles are agglomerated and form insoluble metal hydroxide known as flocks. C. Filtration: Filtration is done in order to remove colloidal and suspended matter remaining after sedimentation and to remove bacterial load. The process of filtration usually consist of allowing the water pass through thick layer of sand or porous material which retain coarse impurities on its surface and in pores. D. Flocculates: Flocculates are organic high molecular weight compound comprising many inorganic group. - These group groups undergo ionization when dissolve in water. Two important flocculates are polyacrylamide BA-2 flocculate. Most of colloidal particles carry negative surface charge but molecule of flocculate are positively Hence neutralization of charges take place.

16. II. Secondary Treatment: It is the process in which microorganism play a very important role for the treatment of effluent. Microorganism like bacteria, fungi decompose the organic waste and convert into simpler form. There are two types of secondary treatment: Aerobic Treatment - The treatment which is carried out by microorganism in the presence of oxygen. Activated Sludge Process Trickling Filter Anaerobic Treatment - The treatment which is carried out by aerobes in the absence of oxygen. The need of oxygen is supplied by oxidation of oxygenated compound for e.g. SO2 Oxygen Pond

17. Aerobic Treatment: A. Activated Sludge Process: Sewage from sedimentation tank enter into aeration tank. Here 20 – 30 % of active sludge is mixed. The mixture is aerated and mixed in the tank for about 4 to 8 hours. An efficient aeration for 3 – 6 hour is occupied for sludge while for industrial waste 6 – 24 hour of aeration is required. The microorganism oxidize organic matter, in the presence of abundant quantity of oxygen in the aeration tank. Sewage is allowed to settle in secondary sedimentation tank. This settled sewage has undergo aeration and has active microorganism. The activated sludge is obtained by settling sewage in the presence of excess oxygen. Thus activated sludge is that sludge which settle down after the sewage has been freely aerated and agitated for a certain time. When activated sludge is mixed with effluent, the aerobic bacteria oxidize the organic matter and promote coagulation and flocculation. Some advantages of activated sludge method are: i . The effluent is free from bed smell and odor ii. Give Clear sparkling treated liquid

18. B. Trickling Filter: After primary treatment the effluent is passed through the bed the filter medium which is consisting of bed of stone in which microorganism or bacteria are present. - Bacteria get nutrient. Bacteria attack on carbohydrate, protein, oil, fats which is essential for the growth of bacteria.

19. Oxidation Pond (Lagoon) The oxygen pond is shallow pond where waste water is purified by action of algae and aerobic bacteria. Latter on oxygen is released during the process of photosynthesis. Aerobic bacteria get O2 from atmosphere and convert the organic matter present in sewage and liberate CO2 which is again taken by algae during the process of photosynthesis. The contents of the aeration tanks are commonly referred to as the mixed liquor suspended solids (MLSS). The activated sludge converts organic substances into oxidized products and a settle able flock which is settled out in the secondary clarifiers.

20. III. Tertiary Treatment or Advance waste water treatment: The main function of tertiary treatment is to decrease the load of nitrogen and phosphorous compound present in the effluent by the following process : Precipitation Nitrogen Stripping Chlorination

21. A. Precipitation: The effluent received after the secondary treatment is mixed with calcium oxide. The lime then react with phosphorous compound in waste to from insoluble calcium phosphate, which then settle down at the bottom of settling tank. B. Nitrogen Stripping: Nitrogen present in waste water is generally in the form of ammonia gas, nitrates and nitrites. Ammonia is highly undesirable in streams and lakes because it is extremely lethal to aquatic biota. Nitrogen eventually enhance Eutrophication In order to remove nitrogen air is forced through the effluent which thereby result in the removal of ammonia gas. C) Chlorination: It is the process in which chlorine is used to kill micro-organism. The main purpose of chlorination are To assist in the formation of floc in the process of coagulation together with other chemical. - To prevent corrosion of sewers. To prevent spread of epidemic.

22. Other advanced methods Some other advanced methods of tertiary treatment are: A. Ultraviolet Light B. Ozone

23. A. Ultraviolet Light: The water is passed through banks of cylindrical, quartz-jacketed fluorescent bulbs. Some dissolved materials, such as iron and some organic compounds, can also absorb some of the light. Ultraviolet disinfection is becoming more popular because of the increasing complications associated with the use of chlorine.

24. B. Ozone: Ozone is too unstable to store, and has to be made as it is used. It is produced by passing an electrical discharge through air, which is then bubbled through the water. While chlorine can be dosed at a high enough concentration so that some of it remains in the water for a considerable time, ozone is consumed very rapidly and leaves no residual. It may also produce some chemical byproducts, but probably not as harmful as those produced by chlorine.

25. IV. Sludge Processing: Sewage processing describes the processes used to manage and dispose of sewage sludge produced during sewage treatment. It has two methods: Anaerobic Digester. Sludge Dewatering and Drying.

26. 1. Anaerobic Digester In the anaerobic digesters another group of bacteria begin to digest and dissolve the solids to their basic components. This process uses bacteria which do not need atmospheric oxygen to survive, so therefore, no air is bubbled into the tanks. The anaerobic digesters produce a stable sludge which is readily dewatered.

27. 2. Sludge Dewatering and Drying The engine generator runs on digester or natural gas. The generator supplies electrical power to essential pieces of treatment plant equipment. After most of the organic solids have been digested, the sludge is pumped to sand drying beds or to the belt filter presses. The dewatered solids are then squeezed between two belts to further dewater them. The resulting solids are in the range of 18-20 percent solids.

28. Conclusion: The issue of industrial effluents concerns every nation on the planet. As a result, many steps have been taken to seek permanent solutions to the problem.. Better technology is being developed for disposal of waste and recycling as much polluted water in the industries as possible. Wastewater treatment is an important initiative which has to be taken more seriously for the betterment of the society and our future.

29. References: M. Samer. (2015). Biological and Chemical Wastewater Treatment Processes. Retrieved from: https://www.intechopen.com/books/wastewater-treatment-engineering/biological-and-chemical-wastewater-treatment-processes Patterson, J W. (1985). Industrial wastewater treatment technology. Retrieved from: https://www.osti.gov/biblio/7253209 Kumar . (2013). Waste water treatment. Retrieved from: https://www.slideshare.net/kumar_vic/waste-water-treatment-18653689 Nusrat Bashir . (2016). Wastewater Treatment. Retrieved from: https://www.slideshare.net/NusratBashir3/waste-water-treatment-ppt Sarita Dhal . (2015). Industrieal Waste. Retrieved from: https://www.slideshare.net/saritadhal37/industrial-waste-48273167