Treatment of wastewater sludge using anaerobic digestion

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 Anaerobic digestion is widely considered as an environmentally friendly technology for various organic waste including sewage sludge. Although the implementation of anaerobic digestion as an alternative treatment method for sewage sludge can be seen in many countries, its status in Malaysia is not clear. This study reviewed the current state of sewage sludge treatment in Malaysia and discussed the challenges to promote anaerobic digestion in sewage sludge treatment. Other than the common constraints faced, namely technical, political and economic, the characteristics of sewage sludge in Malaysia are considered to be a factor regarding feasibility. Anaerobic co-digestion is the simultaneous anaerobic digestion of two or more substrates which is a promising possible option to overcome the disadvantages of mono-digestion, and improve the economic viability due to higher methane production. There are a variety of biomasses as co-substrates in Malaysia. However, the anaerobic co-digestion of food waste and sewage sludge might be the most feasible method to overcome such constraints. Adding food waste as co-substrate is suggested as the possible approach to not only improve the process's performance but also help to handle the increasing volume of food waste in Malaysia. This study aims to highlight the potential as well as to provide a starting point for further studies regarding the treatment of sewage sludge using anaerobic digestion in Malaysia.

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Treatment of Sewage Sludge Using Anaerobic Digestion

Anaerobic digestion is a proven technology for sewage sludge treatment, in which the high water content sewage sludge can be processed without any pretreatment (Ward et al., 2008). The properties of sewage sludge are modified during anaerobic digestion, with not only biogas being produced as a result, but also several positive consequences for the sludge management that follows the process. Anaerobic digestion enhances the stabilization of sewage sludge, reduces pathogens and odor emission, and dry matter of sludge is reduced, which leads to a significant reduction in the final sludge volume. These benefits of anaerobic digestion of sewage sludge are widely recognized, and the technology is well established in many countries. The total biogas production in several countries and biogas production from WWTPs are listed in Table 2 based on the statistics of the International Energy Agency (IEA Bioenergy Task 37, 2017) and the World Bioenergy Association (2017). Germany dominates the worldwide biogas production with 10,431 biogas plants generating 55,108 GWh/y of electricity. It has 1, 258 sewerage plants generating 3,517 GWh/y of electricity. Although India has 83,540 biogas plants, bioenergy production is still at a household mode and has been limited to small size biogas plants which are used by the people especially in rural areas. On the other hand, in Malaysia, IWK has taken over 4,281 small plants for upgrading to large plants by 2013. Overall IWK has 35 large plants (Indah Water Konsortium Sdn Bhd, 2013) which is 247 GWh/y electricity generated in 2017 (Sustainable Energy Development Authority Malaysia, 2018)3.

REFERENCE:-

 https://www.frontiersin.org/articles/10.3389/fenrg.2019.00019/full

 

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