Li Yiyong, Hu Yongyou, Huang Guofu, Yu Ziqi, Bi Wei, Fan Hao, Du Jianjun
College of Environment Science and Engineering, Zhongkai University of Agriculture and Engineering Guangzhou Guangdong 510225 China.
Guangdong Provincial Engineering and Technology Research Center for Agricultural Land Pollution Prevention and Control Guangzhou 510225 China.
RSC Adv. 2018 Nov 1;8(64):36951-36958. doi: 10.1039/c8ra06726k. eCollection 2018 Oct 26.
Pretreatments have been successfully used to shorten the HRT of anaerobic digestion (AD) of sewage sludge, but they become ineffective for low-organic sewage sludge, with HRT > 10 days. Herein, a new process using alkaline hydrolysis-anaerobic digestion has been developed to solve this problem. Firstly, maximum organic matter in the sludge was dissolved by strong alkaline hydrolysis (pH > 11) in a two-stage alkaline hydrolysis system (TSAHS). Secondly, only the supernatant of the sludge that contained most of the methane potential was applied for AD. The operational conditions were optimized and the process mechanism was also analyzed. The results showed that under optimum operational conditions, above 19% of the organic matter in the sludge was released into the supernatant after alkaline hydrolysis in TSAHS, and the supernatant for AD achieved a methane production of 392 mL CH per g COD. The process attained a methane production of 0.26 m CH per kg VS and a VS reduction of 43.5%, while the HRT was only 12 h. The advantage of the mechanism was that the alkaline neutralization capacity of the sludge maintained a proper pH value for the supernatant from TSAHS, which benefited subsequent AD. It is concluded that the new process based on the dissolution of organic matter can attain a short digestion time for low-organic sludge.
预处理已成功用于缩短污水污泥厌氧消化（AD）的水力停留时间（HRT），但对于HRT>10天的低有机污水污泥，预处理变得无效。在此，开发了一种使用碱性水解-厌氧消化的新工艺来解决这一问题。首先，在两级碱性水解系统（TSAHS）中通过强碱性水解（pH>11）溶解污泥中的最大有机物。其次，仅将含有大部分甲烷潜力的污泥上清液用于厌氧消化。对运行条件进行了优化，并分析了工艺机理。结果表明，在最佳运行条件下，TSAHS中碱性水解后，污泥中19%以上的有机物释放到上清液中，用于厌氧消化的上清液实现了每克化学需氧量（COD）产甲烷392毫升。该工艺每千克挥发性固体（VS）产甲烷0.26立方米，VS减少43.5%，而HRT仅为12小时。该机理的优势在于污泥的碱中和能力为TSAHS的上清液维持了合适的pH值，这有利于后续的厌氧消化。得出的结论是，基于有机物溶解的新工艺可以实现低有机污泥的短消化时间。
