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Prof. Curran/Dr. Saunders, 2013, project template v2Recycling Waste WaterBy ‘Author Name’Affiliation (MSc Profile or Track) & Study no.Executive SummaryThe current project emphasizes uponrecycling waste waterwhich has become the need of thehour. The contents of this project provide avenues to study various issues dealing with currentwater management and highlight various challenges in addressing them. With the central themeof waste water management, the main aim of this project is to augment the understanding of itsreaders about the global developments in the field of waste water management and inspire toundertake viable state-of-the-art methods of recycling waste water. This report concentrates onthe main water users, namely public water supply including households, agriculture and industry.This research is based on a large literature review and data analysis of existing studies andexperiences of water savings in countries like US, Australia and Japan. This literature review iscomplemented by case studies that illustrate the feasibility of implementation and likely impactsof potential water savings measures. The study presents theoretical content on recycling wastewater and also critically makes an attempt to showcase potential grey areas where there is barrierfor implementation of waste water recycle systems. The scenario in case of developed countriesis different than developing countries which are reluctant to employ water reuse technology dueto cost factor and lack of public awareness. During research study it was revealed that there is ahigh data gaps and data uncertainty in estimating today’s water abstraction and consumption,current applications of water saving technologies or future trends in water consumption andwithdrawals. Thus, analysis presented in this report provides an order of magnitude of the waterrecycle potential but detailed figures should be used with caution. In addition, a detailed analysiswould be necessary to take into account the regional specificities of water uses.1.IntroductionWater is, unarguably, an utmost important commodity in our day to day lives. Its importance canbe attributed to the fact that many ancient civilizations flourished or perished because of itsavailability or scarcity. Today’s most populous inhabited areas of the world are located nearwater resources. It is a fact that water usage has grown significantly in recent years owing torapid economic development. According toUnited Nations Environment Programme(UNEP) itis predicted that water withdrawal will rise by 50 percent in developing countries and 18 percentin developed countries by 2025.
Prof. Curran/Dr. Saunders, 2013, project template v2This increase in water usage makes water scarcity a serious issue for many countries especiallythose that frequently experience periods of drought and other environmental challenges. Withincreasing urban population, changing lifestyles and industrialization, the quality of water hasdeteriorated over the years and hence there is a serious requirement of its treatment before it canbe recycled for any purpose. The main sources of water pollution are due to industrial activities,domestic and agricultural activities and other environmental and global changes. Both the surfaceand ground water are getting contaminated at many places of the world and are not fit fordrinking and other consumption purposes. Water supply is also reported to be dwindling in manyareas of the world due to overexploitation of existing water resources including ground water. Itis estimated that by 2020, the global population will reach up to 7.9 billionmark andconsequently world may experience greater scarcity of water. Hence, there’s been a continuouseffort by mankind to improve and preserve its quality.In view of this, attempts have been made to compare various water treatment and recyclingtechnologies. Efforts have also been carried out to introduce an approach for water treatment andrecycling methods. A comparison of the technologies has been presented by discussing theirperformance, sludge production, life period and operation. The purpose of this research work is toprovide guidelines for the selection of the technologies or their combinations for variousapplications so that one can select the exact and correct technology depending upon therequirement and prevailing local conditions.2.State-of-the-art/Literature ReviewTraditionally, industries and processes were envisaged and designed without the consideration ofwastes that they would produce or the potential environmental impact that they have on ecology(Unnikrishnan and Hegde, 2005). During the course of time legislation were enacted andestablished and compliance issues evolved, the wastewater treatment industry began takingshape, with an end-of-pipe treatment focus that aimed at cleaning up the combined wastewaterprior to discharge (Savelski and Bagajewicz, 2000). Based on the type and concentration of thespecific contaminants present in waste water, the treatment level for wastewater defined asprimary, secondary, tertiary and quaternary with unit operations classified as physical,chemical, thermal and biological (Savelski and Bagajewicz, 2000).The perspective of water usage has also changed for industry because as water has becomescarcer, energy costs have risen and discharge regulations more stringent. Strategies involvingwastewater reuse and/or recycling, directly impact on freshwater inputs and wastewater outputsrequiring treatment (Savelski and Bagajewicz, 2000; Savelski and Bagajewicz, 2001).Eventually, the concept of zero discharge was born (Savelski and Bagajewicz, 2000).Two approaches are often used to reduce or minimize adverse impacts associated with treatingand disposal of industrial wastes these being the ‘end of pipe’ and the ‘cleaner production’approach. An end of pipe approach focuses on cleaning up the wastes or emissions after they
Prof. Curran/Dr. Saunders, 2013, project template v2have been produced (Hilson, 2000b; Zbontar and Glavic, 2000) which has been the traditional approachtowards meeting imposed discharge limits (Savelski and Bagajewicz, 2000; Savelski and Bagajewicz,2001). Typically wastewater treatment operations are designed to remove “...settleable, suspended, anddissolved solids, organic matter, metals, nutrients and pathogens from wastewater” (Mujeriego and Asano,1999). These end-of-pipe approaches have proven inadequate for firms to meet minimisation andcompliance goals, compared to preventative approaches (Hilson, 2000b). Eastwood and Tainsh (1999)accurately state:Don’tsolveanEnd-Of-PipeproblemwithanEnd-Of-Pipesolution.UnlessyouhaveexploredtheIn-processsolutions,yourEnd-Of-Pipesolutioncouldbetheworstsolutiontoyourproblem!‘Cleanerproduction’isalsoreferredtoaspollutionprevention(Taylor,2005)andisaproactivepreventativemeasuresupportingsustainabledevelopmentthatisintegratedintotheprocessdesigntoachievesignificantenvironmentalimprovement(Jiaetal.,2005).Itaddstothebottomlineintermsofconservingenergy,materialsandmanpowerwhileincreasingyieldsanddecreasingtreatmentanddisposalcosts(UnnikrishnanandHegde,2005).AsexpressedbyEastwoodandTainsh(1999),“goodsolutionsoftendomorethansavewater”astheycanalsoreducecapitalinvestmentandrecoverrawmaterialsotherwiselost.Reclaimedwater,asanalternativewatersupply,alsohasaneconomicvalue(MujeriegoandAsano,1999).UnnikrishnanandHegde(2005) in their research has laid down someprovencleanerproductionapproachesusedbymanufacturingindustries,which are as oinclude:BettermanagementofmaterialandenergyflowsMoreefficientprocesscontrolOptimizationofreactorandprocessconditionsIn-processrecycle-reuseofby-productsandsolventsRecoveryofwastethermalenergy3.Research Question, Aim/Objectives and Sub-goalsThis proposal work is intended to lend an insight into waste water treatment and recyclingtechniques. So readers might be curious to know what, why and how of waste water recycling.One may typically ask what is meant by recycling of waste water? Why recycling is needed?What are the ways of recycling of waste water? How it is exactly done? What are the pros & consof such techniques?So, basically the central aim of this project is to study various issues related to water managementand its usage and draw upon various prevalent and viable techniques for recycling of waste water.The same has been attempted to achieve through literature study and dousing various researchjournals and publications. This research makes an attempt to presents the gaps in wastewaterresearch, the conceptual framework for the research and the methodology that can be used to
Prof. Curran/Dr. Saunders, 2013, project template v2tackle the problems associated with wastewater in both developing and developed countriesframework.The central component of this approach is the physical pathway through which wastewater isgenerated, collected, treated and distributed, which is the common component for all thecountries irrespective of their economic status. It is then argued that the emphasis on differentphases of this pathway depends on the level of development in any region. As regions becomemore developed they concentrate on factors further down the pathway.4.Theoretical Content/MethodologyRecycling wastewater is a process of treating, convertingwastewaterinto purified water that canbereusedfor other purposes. The purified water thus reclaimed can be reused forirrigationpurposes, replenishingsurface waterandgroundwater recharge. It can also be used to satisfycertain residential needs liketoiletflushing, gardening, and if treated properly for drinking waterstandards.Instead of using freshwater supplies, recycling waste water for reuse applications can be a water-saving measure.Discharging used water back into natural water sources can still have benefits toecosystems. For e.g. natural water cycle usage could include recharging aquifers, improvingstream flow, sustaining plant life.Traditionally, wastewater reuse has been a long-established practice for irrigation and relatedactivities in arid and semi arid countries. Reusing wastewater through recycling has beenconsidered a part of sustainablewater managementwhich makes recycle waste water analternative water source for human activities. This can reduce demand for water and minimisepressures on groundwater and other natural water resources.A typical pathway of wastewater consists of four phases:A. Wastewater generation:Wastewater generated in the urban areas is huge and continues togrow over time with increasing urbanization and changing lifestyles. As cities are the centers ofeconomic and political powerhouse, their water requirements usually receive a higher priority.However, such cities are subject to physical and economic scarcity constraints. Increases in urbanwater supply ensure increased wastewater generation. The depleted fraction of domestic andresidential water use is typically only 15-25% and the remainder returns to wastewater (Scott etal. 2004).B. Wastewater collection: Most cities in the developing world are only partially sewered,resulting in substantial volumes of wastewater (including toilet wastes) finding their way intosurface water networks within cities. On an average only 28% of the population in the developingworld in large cities is actually sewered, whereas more than 90% of the population is sewered indeveloped countries (WHO and UNICEF 2000).C. Wastewater treatment:The sewage network is used to bring wastewater to the treatmentplant. It can then be treated to primary, secondary or tertiary levels before it is discharged for
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