Decentralized Wastewater Treatment- Working paper review


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Comments on the working paper of integrated wastewater treatment for rural areas with focus on resource recovery.

Introduction- Wastewater is used to define any water that contains in-commensurable effluents dissolved in it. It consists of industrial and domestic wastes, waste from agriculture and farming, storm water, water from sewers and other activities. Wastewater contains multifarious pollutants including physical, chemical and biological pollutants. Efforts are made to treat these pollutants and to recycle and reuse the water. According to United Nations World Water Development Report, treating wastewater generates social, economic and environmental benefits necessary for the sustainable development- an agenda to be achieved by 2030. that depicts the different treatment methods for the wastewater in rural areas and the most suitable method for the wastewater treatment in rural areas.

Impression about the work- The paper begins with an introduction of the wastewater and the multifarious problems associated with the wastewater in both rural and urban areas with the major focus of the paper on the wastewater treatment in rural areas. Then it depicts about the methods of treating wastewater and with the extensive literature review they come on the conclusion that decentralized wastewater treatment approach is benefaction for the rural areas, the reason being, it requires less energy consumption and it is flexible as mentioned in the paper. The paper does not mention any serious disadvantage of decentralized wastewater treatment system. One of the important disadvantages of this type of system is it is located near to the human settlements so there’s problem of odor and overflow, small treatment plants exist, it is difficult to manage, sludge handling. The paper further remarks about the different types of wastewater treatment methods available along with the methods that are most suitable in the rural areas (Gupta, N. (2016) Centralized v/s Decentralized wastewater treatment solutions’, International Journal for scientific research and development , vol 4, issue 01, pp. 1019-1020)

Furthermore, it describes primary and secondary wastewater treatment methods. In the primary wastewater treatment method one of the methods is Septic tank method and the paper does not mention about the serious disadvantage of this type of tank. “The main cause of failure of septic tank is unsuitability of soil and site characteristics. The impurities present in wastewater can clog the tank, to cope with this problem modified septic tanks are used which consists of filter as an additional component to provide advance primary treatment” (Massoud, 2007). “Imhoff tank is another method that accommodates higher flow rates, but it’s not so common. They are mainly used where soil quality is poor, site is sensitive and land availability is less” (Massoud, 2007). In secondary treatment methods lagoons are the most important method which in not present separately in the paper. Lagoons are most important methods for removing disease causing organisms. Lagoon methods are inexpensive and cost-effective method that can remove various settleable solids. It’s easy to operate and maintain and is used in areas where land is expensive. The drawbacks of this type of method is that it fails to remove heavy metals and there is high sludge accumulation in it. The multitude of arguments present in favor of Integrated Decentralized Wastewater system for rural areas system in the paper are good enough to support this system (Massoud, 2007).

As mentioned in the paper Sustainable integrated system is no doubt the most appropriate technology for treating wastewater. If a process is sustainable then it is environmentally friendly, economically affordable and socially acceptable. But in the real world there are certain limitations for the sustainable system. It’s not that sustainable system is not possible, it is possible and for it to work there are certain limitations that we must overcome. Like it is less financially rewarding, people repelled by “purified sewage” water, high energy consumption, and requires more maintenance ( Advantages and disadvantages of sustainable system. Available at: https://www.lorecentral.org/2018/07/advantages-and-disadvantages-of-sustainable-development.html)

Conclusion - This paper presents harmful effects of wastewater and methods of treating wastewater. There’s always a contention between the approaches as to what approach must be taken to treat wastewater, which indubitably depends upon the type of soil available in region, terrain of the region, water table in the region and climate. Based on the extensive literature review, decentralized wastewater treatment is pertinent in rural areas. It’s simple, cost effective, flexible, easily operable and sustainable method in rural areas. An elite example of case study of the integrated decentralized wastewater treatment is Hamburg water cycle in Jenfelder Au, Germany, as illustrated in the paper. Its most critical component is, separate treatment of different wastewater streams also called as partial flow treatment. It is shown that blackwater combined with local water stream can be used for biogas generation and fertilizer. Another case study is that of Ecological Sanitation Pilot Plant in Surabaya, Indonesia as depicted in the paper. Two factors that will influence the research in the field of Ecological Sanitation system in the coming years will be realization of “integrated” post-urine diversion waste fractions as these steps harbor the most potential for value creation and risk minimization and addressing issues with pharmaceuticals , pathogens and micro pollutants in the source- separated waste by identifying and implementing ecologically- sound treatment processes that ensures ‘safe reuse’ of wastes as fertilizers (Simha and Ganesapillai, 2017).

References

Khalid, U. and Garcia.C (2018). Integrated wastewater treatment for rural areas with focus on resource recover., Hamburg: Ruvival, pp. 1-27.

Massoud, M. Tarhini, A. and Nasr, J. (2007) Decentralized approach to wastewater treatment and management’: Applicability in developing countries. Beirut: Elsevier, pp. 652-659.

Simha, P. and Ganesapillai, M. (2017) Ecological sanitation and nutrient recovery from human urine vol 27, issue 03, 2017.

Nitika Gupta, 2016, ‘Centralized v/s Decentralized wastewater treatment solutions’, International Journal for scientific research and development , vol 4, issue 01, 2016.