Anaerobic co-digestion of the sewage sludge pyrolysis liquids and cow dung under thermophilic condition
YANG Min1, CHEN De-zhen1, DAI Xiao-hu2
1. Thermal & Environment Engineering Institute, Tongji University, Shanghai, 201804, China;
2. National Engineering Research Centre for Urban Pollution Control, College of Environmental Science & Engineering, Tongji University, Shanghai 200092, China
In order to treat sewage sludge pyrolysis liquid (SS-PL) and recover its energy, the anaerobic digestion of SS-PL produced in the temperature range of 250~550℃ and co-digestion of SS-PL with cow dung (CD) were studied. Firstly, SS-PL produced at 250℃~550℃ were inoculated to verify whether they can be digested. The results showed that SS-PL would produce some biogas; and the SS-PL produced at 350℃ (PL350) had the highest biogas yield; but for all of the SS-PLs their biogas yields are very little. Therefore, SS-PL produced at 250℃(PL250) was adopted as an example to mix with CD by different mass ratio (5/80, 10/80, 15/80; g/g) for co-digestion at (55±1)℃; and it has been found that PL250 inhibited the anaerobic digestion of CD; the higher the PL250/CD mass ratio, the more serious the inhibitory effect was. Then in the next step, SS-PLs produced at four different pyrolysis temperatures (PL250, PL350, PL450 and PL550) were mixed with CD respectively by ratio of 5/80 and subjected to anaerobic digestion under 55±1℃ to check the influence of pyrolysis temperature. The results showed that the biogas generation from the mixture of PL350 and CD was the highest (116.42mL/g VS), it was even higher than that of the controlled group (CD alone), which was 110.36mL/g VS, the followed sequences are mixtures added with PL550, PL450 and PL250 respectively. In addition, the total volatile fatty acid (TVFA) in the mixture group of PL550/CD was the highest in the beginning (1528mg/L), but reduced to 254mg/L after digestion, proving that the organic matter in SS-PLs was effectively decomposed. Generally SS-PL produced at an appropriate temperature can be co-digested with CD at a suitable blending ratio, providing a new alternative for its disposal and energy recovery.
杨敏, 陈德珍, 戴晓虎. 污泥热解液与牛粪混合厌氧消化特性研究[J]. 中国环境科学, 2018, 38(2): 634-642.
YANG Min, CHEN De-zhen, DAI Xiao-hu. Anaerobic co-digestion of the sewage sludge pyrolysis liquids and cow dung under thermophilic condition. CHINA ENVIRONMENTAL SCIENCECE, 2018, 38(2): 634-642.
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