Methane recovery from digesting domestic mixed sewage sludge

Seswoya, Roslinda (2017) Methane recovery from digesting domestic mixed sewage sludge. PhD thesis, Universiti Tun Hussein Onn Malaysia.

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Abstract

Knowing that sewage sludge is considered as a renewable energy source, research on the anaerobic digestibility or biochemical methane potential (BMP) production of untreated domestic mixed sewage sludge (DMSS) and thermally pre-treated DMSS were conducted. This study aimed to estimate the methane recovery from untreated DMSS and thermally pre-treated DMSS (at temperature of 90oC at 40 minutes and 90oC at 60 minutes) using the mesophilic anaerobic digestion. The BMP tests fed with untreated DMSS were prepared and labelled as BMP MSNT. Meanwhile, two types of thermally pre-treated DMSS namely; MST 9040 and MST 90120 were used as substrate for batch BMP test and each test was labelled as BMP 9040 and BMP 90120 respectively. The ultimate methane yield from the mesophilic anaerobic digestion (BMP MSNT) was higher than that observed from digestion of disintegrated sewage sludge ( BMP 9040 and BMP 90120). However, the methane yield at day 5 from BMP 9040 was 1.05% higher than BMP MSNT. Meanwhile, BMP 90120 produced higher methane yield, an increase of 6.08 % at day 5 compared to the BMP MSNT. The higher net accumulated methane yield for anaerobic digestibility of MST 90120 could be due to the presence of higher volatile fatty acid (VFA), which was dominated by acetic acid. In addition, the DMSS disintegration at 90oC was able to improve the net maximum methane production rate, better than what was observed from the digestion of untreated DMSS especially from the digestion of thermally pre-treated DMSS at 120 minutes as indicated by BMP 90120. The results of this experiment concurred with the findings derived using kinetic modeling; the maximum methane production rate, Rm determinutesed by Modified Gompertz Model. This proved that low thermal pre-treatment was able to improve the methane yield during the early stage of degradation and subsequently increase the net maximum methane production rate.

Item Type:Thesis (PhD)
Subjects:T Technology > TD Environmental technology. Sanitary engineering > TD511-780 Sewage collection and disposal systems. Sewerage
ID Code:10240
Deposited By:Mr. Mohammad Shaifulrip Ithnin
Deposited On:13 Aug 2018 11:28
Last Modified:13 Aug 2018 11:28

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