Wastewater Recycling

Wastewater recycling is emerging as an integral part of
water demand management. Promoting as it does the preservation of high-quality fresh water supplies as well as potentially reducing the pollutant in the environment and reducing overall costs.

1. Waste water Recycling S.Vignesh, BTG-12-037 Dr.A.Valliammai, Assistant Prof.,(WTC)

2. Waste Water It is any  water that has been adversely affected in quality by  naturally or anthropogenic  influence. Wastewater is water containing wastes from residential , commercial, and industrial processes. Municipal wastewater contains sewage , gray water. Wastewater requires treatment to remove pollutants prior to discharge. 

3. Wastewater Recycling Wastewater recycling is emerging as an integral part of water demand management. Promoting as it does the preservation of high-quality fresh water supplies as well as potentially reducing the pollutant in the environment and reducing overall costs.

4. Motivational Factors Opportunities to augment limited primary water sources. Prevention of excessive diversion of water from alternative uses , including the natural environment. Possibilities to manage in-situ water sources . Reduction and elimination of discharges of wastewater ( treated or untreated) into receiving environment. Scope to overcome political, community & institutional constraints .

5. Reuse Potential reuses of wastewater depends on the hydrau. and biochemical characteristics of wastewater, which determine the methods and degree of treatment req. It can be recycled/reused as a source of water for a multitude of water-demanding activities such as agriculture , aquifer recharge, aquaculture, fire fighting, flushing of toilets, snow melting, industrial cooling, parks and formation of wetlands for wildlife habitats, recreational impoundments .

6. Quality of Wastewater Wastewater , if treated appropriately, has the potential to be recycled in a number of sectors . Recycled water can be treated to a number of different standards using different technologies depending on the quality req. Broadly , wastewater is treated to three levels, namely primary , secondary and tertiary levels. According to the Environment Protection Agency (EPA) , they are defined as follows:

7. Methods Wastewater treatment is closely related to the   standards and/or expectations set for the effluent quality . Suspended solids  (physical particles that can clog rivers or channels as they settle under gravity)

8. Biodegradable Organics Microorganisms combine this matter with oxygen from the water to yield the energy they need to thrive and multiply; Unfortunately , this oxygen is also needed by fish and other organisms in the river. Heavy organic pollution can lead to “dead zones” where no fish can be found; sudden releases of heavy organic loads can lead to dramatic “fish kills”.

9. Pathogenic Bacteria These are most relevant where the receiving water is used for drinking , or where people would otherwise be in close contact with it. Nutrients These nutrients can lead to high concentrations of unwanted algae, which can themselves become heavy loads of biodegradable organic load Treatment processes may also neutralize or removing industrial wastes and toxic chemicals. 

10. 1.Primary treatment: Treatment involving sedimentation (sometimes preceded by screening and grit removal) to remove gross and settle able solids. The remaining settled solids, referred to as sludge, are removed and treated separately . 2.Secondary treatment: Generally , a level of treatment that removes 85% of Biological Oxygen Demand [BOD] and suspended solids via biological or chemical treatment process. Secondary treated reclaimed water usually has a BOD of <20 milligrams per liter ( mg/L) and suspended solids of <30 mg/L , but this may increase to >100 mg/L due to algal solids in lagoon systems .

11. 3.Tertiary treatment: The treatment of reclaimed water beyond the secondary biological stage . This normally implies the removal of a high percentage of suspended solids and/or nutrients, followed by disinfection. It may include processes such as coagulation, flocculation and filtration.

12. Wastewater Sludge Reuse Wastewater sludge is the solid/semi-solid substance, concentrated form of mainly organic, and inorganic impurities, generated as a result of treatment of wastewater. It can be reused to reclaim parched land by application as soil conditioner, and also as a fertilizer in agriculture. Deteriorated land areas, which cannot support the plant vegetation due to lack of nutrients, soil organic matter , low pH and low water holding capacity, be reclaimed and improved by the application of sludge…Etc.

13. Economic Characters Centralized wastewater treatment systems, the location of the treatment plants, the availability of space in and around cities and the topography – all of these factors restrict the use of wastewater to certain areas and for specific purposes. There are both positive and negative externalities associated with wastewater recycling. The positive externality is: environmental benefits from reduced discharge of saline wastewater into natural water bodies. The negative externalities include potential groundwater pollution and increase in soil salinity if used for irrigation and potential unknown ill effects on human health if used for potable uses

14. Government / Institutions roles I. Environmental Protection Agency Responsible for the developing and applying of best practice management guidelines for reclaimed water irrigation II. Department of human services Responsible for ensuring that, reuse schemes do not pose a risk to public health III. Council/Local Government Councils control development zoning, minimum subdivision size, infrastructure size, infrastructure provision, and land use controls

15. Conclusion Today, these methods are most widely used in wastewater treatment process. An economic and reliable way of using solar energy for effluent treatment is a very attractive option for Indian industries since the life of the catalyst is long. Also many possible synergism of these techniques promise a good pollutant destruction rate that helps in maintaining the environment clean.

16. Reference ABS. 2005. Annual Report 2005-06. http:// www.ausstats.abs.gov.au/ausstats/subscriber.nsf am (Canberra Time) 28 November 2006. Australian Bureau of Statistics. Commonwealth of Australia. http://www.tn.gov.in ACIL Tasman Pty Ltd. 2005. Economics Policy Strategy. Research into access to recycled water and impediments. recycled water investment. Report prepared for the Australian Government Department of Agriculture, Fisheries. and Forestry on behalf of the Natural Resource Policy and Programs Committee. June 2005 .

17. Thank You