04 Reclamation and Reuse of waste water
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The document discusses wastewater reuse and management, highlighting processes for treating and recycling wastewater for various applications such as irrigation and industrial use. It covers the advantages and disadvantages of wastewater reuse, including public perception and infrastructure costs, and explains the self-purification processes of natural water bodies. Specific technologies and methods for wastewater treatment and disposal, including examples from India, are detailed alongside standards for effluent discharge.
04 Reclamation and Reuse of waste water
- 1. Environmental Engineering- II By Akash Padole Department of Civil Engineering Reclamation and Reuse of Waste water
- 2. Contents 4.1 Tertiary and Grey water treatment, recycling and reuse of wastewater. 4.2 Self-Purification of Natural Water Bodies: Oxygen economy, Sewage farming. Disposal of treated effluent Disposal of Raw and treated sewage on land and water, standards for disposal. Stream Pollution: Self-purification, DO sag curve Akash Padole 2
- 3. What is Wastewater Reuse? • Reclaimed or recycled water (also called wastewater reuse or water reclamation) is the process of converting wastewater into water that can be reused for other purposes. • Reuse may include irrigation of gardens and agricultural fields or replenishing surface water and groundwater (i.e., groundwater recharge). Akash Padole 3
- 4. • Reused water may also be directed toward fulfilling certain needs in residences (e.g. toilet flushing) and industry, and could even be treated to reach drinking water standards. Akash Padole 4
- 5. • Reclaiming water for reuse applications instead of using freshwater supplies can be a water-saving measure. • When used water is eventually discharged back into natural water sources, it can still have benefits to ecosystems, improving streamflow, nourishing plant life and recharging aquifers, as part of the natural water cycle. Akash Padole 5
- 6. • Wastewater reuse is a long-established practice used for irrigation, especially in arid countries. • Reusing wastewater as part of Sustainable Water Management allows water to remain as an alternative water source for human activities. • This can reduce scarcity and alleviate pressures on groundwater and other natural water bodies. Akash Padole 6
- 7. Categories or Types of Reuse • Urban Reuse: – Irrigation of public parks, sporting facilities, private gardens, roadsides; Street cleaning; Vehicle washing; Toilet flushing. • Agricultural Reuse: – Food crops not commercially processed; Food crops commercially processed; Pasture for milking animals; Fodder; Seed crops; Orchards; Hydroponic culture; Aquaculture. Akash Padole 7
- 8. • Environmental Reuse: – Aquifer recharge; Wetlands; Marshes; Stream augmentation; Wildlife habitat; Silviculture. • Potable Reuse: – Aquifer recharge for drinking water use; Augmentation of surface drinking water supplies; Treatment until drinking water quality. • Industrial Reuse: – Processing water; Cooling water; Recirculating cooling towers; Washdown water. Akash Padole 8
- 9. New technologies and approaches used in Wastewater Reuse ✓ Membrane Filtration Systems ✓ Nanotechnology ✓ Microbial fuel cells ✓ Natural treatment systems ✓ Urine separating toilets Akash Padole 9
- 10. Advantages of Wastewater Reuse • As long as it is properly treated, recycled water can meet most water demands. • Following is a short list of the most common uses for recycled water: ✓ Agricultural irrigation ✓ Toilet flushing ✓ Dust control ✓ Construction projects ✓ Industrial applications ✓ Landscape irrigation ✓ Cooling water for power plants ✓ Park and golf course irrigation ✓ Mixing concrete ✓ Car and truck washes Akash Padole 10
- 11. Disadvantages of Wastewater Reuse • Cost: – Using recycled water can mean increased costs for infrastructure such as additional treatment facilities and extra pipes to transport it. • Public Perception: – Using recycled water, especially as drinking water, requires overcoming public opinion, which can be difficult . • Health Aspects: – Recycled water used appropriately poses little to no health risk. Akash Padole 11
- 12. Self-Purification of Natural Water Bodies: Akash Padole 12
- 13. Disposal of sewage effluents Akash Padole 13
- 14. Disposal by Dilution • In this process, the treated sewage or the effluent from the sewage treatment plant is discharged into a river stream. • The discharged sewage, in due course of time is purified by what is known as Self Purification Process of natural waters. Akash Padole 14
- 15. Conditions favoring Disposal By Dilution • When sewage comparatively fresh (4 - 5 hrs. old) and free from floating and settleable solids. • When the diluting water (i.e. the source of disposal) has a high Dissolved Oxygen (D.O) content. • When the outfall sewer of the city or the treatment plant is situated near some natural waters having large volumes. Akash Padole 15
- 16. Standards of Dilution based on Royal Commission Report Akash Padole 16
- 17. BIS standard for discharge of Sewage And Industrial Effluent in Surface Water Source and Public Sewers Akash Padole 17
- 18. • The automatic purification of polluted water by Dilution, Sedimentation, Oxidation-reduction in Sunlight, etc. in due course is called Self Purification Phenomenon Akash Padole 18
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- 21. Sedimentation: • The settleable solids, if present in sewage effluents, will settle down into the bed of river, near the outfall of sewage • Which get gradually decompose by the action of microorganisms making the river water free from it. Akash Padole 21
- 22. Sunlight: • The sunlight has a bleaching and stabilizing effect of bacteria. • It also helps certain micro-organisms to derive energy, and it’s called Photosynthesis. Akash Padole 22
- 23. Oxidation and Reduction • Oxidation is a organic matter present sewage effluent, will start as soon as the sewage outfall into the river water containing dissolved oxygen. • Reduction occurs due to hydrolysis of organic matter settled at the bottom either chemically or biologically. • Anaerobic bacteria will help in splitting the complex organic constituent of sewage into liquid and gases, and thus paving the way for their ultimate stabilization by oxidation. Akash Padole 23
- 24. Zone of Pollution of River Stream Akash Padole 24
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- 27. DO sag Curve Akash Padole 27
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- 36. Disposal of waste water at SEA Akash Padole 36
- 37. Love Grove Waste Water Treatment Facility • An Indian example of discharge of city's sewage into the sea can be seen in Mumbai city, where the Love Grove Waste Water Treatment Facility Terminal at Worli Mumbai, is disposing of the partially treated sewage at 3.5 km distance inside the sea, via. an underground marine outfall tunnel, at 65 m below the ground level, after removing the floating material and inorganic solids through the screens and aerated grit chambers. Akash Padole 37
- 38. • This STP (Sewage Treatment Plant) facility is designed for treating a peak flow of 1820 MLD. • The sewage discharge from the area comprising of Church Gate on South to Dadar on North, Mumbai Harbour, Ray Road, Seweri on the East and Arabian Sea on the West, flows upto this STP site, and is lifted, at the Influent Pumping Station (IPS) containing seven duty pumps (with one additional standby unit), each having a designed capacity of 260 MLD each for a designed head of 12.5 m. Akash Padole 38
- 39. Disposal on Land • It is wastewater spread on the surface of land. Mechanism: • Some part of the wastewater evaporates; other part percolates in the ground leaving behind suspended solids which are partly acted upon by the bacteria and partly oxidized by exposure to atmospheric actions of air, heat & light. Akash Padole 39
- 40. Methods of Land Treatment Akash Padole 40
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- 43. Methods of Application of Sewage on Land A. Surface Irrigation (Broad Irrigation) a. Free Flooding b. Check Flooding c. Border Flooding d. Basin Flooding B. Sub-surface irrigation (directly apply to root zone) C. Spray or Sprinkle Irrigation (spread over the soil through nozzle) Akash Padole 43
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- 48. Sewage Sickness & its Prevention Akash Padole 48