水热预处理对猪粪厌氧消化及沼液生态安全性的影响  

Effects of hydrothermal pretreatments on the anaerobic digestion of pig manure and ecological safety of biogas slurry

作　　者：董仁杰[1] 张紫嘉 刘晟 马艳芳 柳珊[1,2] Dong Renjie;Zhang Zijia;Liu Sheng;Ma Yanfang;Liu Shan(College of Engineering,China Agricultural University,Beijing 100083;Yantai Research Institute,China Agricultural University,Yantai 264670)

机构地区：[1]中国农业大学工学院,北京100083 [2]中国农业大学烟台研究院,烟台264670

出　　处：《农业工程学报》2022年第6期193-203,共11页Transactions of the Chinese Society of Agricultural Engineering

基　　金：山东省自然科学基金青年项目(ZR2020QE240)。

摘　　要：为进一步提高猪粪在厌氧消化过程中水解性和产甲烷性能,同时增加猪粪沼液还田利用途径的生态安全性,该研究采用水热的方式对猪粪进行预处理,探究了不同温度(70、90、120、150和170℃)水热预处理对猪粪的理化特性和厌氧消化产甲烷性能的影响,并对其沼液的生态安全性进行评估。结果表明,不同温度水热处理30 min条件下,猪粪SCOD(Soluble Chemical Oxygen Demand,溶解性化学需氧量)增加了3.9%~43.6%;经150℃水热处理后的猪粪获得最高的产甲烷量(398±40)mL/g(以VS计算,Volatile Solid,挥发性固体),相对于未经处理猪粪的产甲烷量显著提高了5.6%(P<0.05)。猪粪经150℃水热预处理和厌氧消化后的沼液中重金属Hg、As、Pb、Cr和Cd含量均满足《农用沼液(GB/T 40750—2021)》的限量要求;粪大肠杆菌的含量满足《粪便无害化卫生要求(GB7959—2012)》;土霉素大幅度降低,恩诺沙星、磺胺嘧啶和诺氟沙星的含量均低于检测限。因此,适当的水热预处理(150℃)不仅能够提高猪粪的厌氧消化产甲烷性能,并且能够进一步加强粪污无害化处理和降低沼液还田利用的环境风险。Biogas production via anaerobic digestion(AD) can effectively utilize pig manure to produce methane instead of fossil energy. However, a large amount of lignocellulose contained in the pig manure cannot be fully decomposed during hydrolysis in the methane production during AD. Therefore, it is necessary to adopt the appropriate pretreatment for the better hydrolysis and AD performance of pig manure. It is also a high demand to consider the ecological safety index(e.g. heavy metals Cr, As, Cd, Hg, and Pb, Escherichia coli) of anaerobic digestates as agricultural organic fertilizers. A hydrothermal treatment can be widely expected to improve the biodegradability of materials, where the hemicellulose can be deconstructed to dissolve the organic matter at high temperature and pressure. Thus, it is supposed that the hydrothermal treatment of pig manure can be extended for the subsequent methane conversion. In this study, a systematic investigation was conducted to clarify the effects of hydrothermal pretreatment at different temperatures(70, 90, 120, 150, and 170 ℃) on the physicochemical properties and AD performance of pig manure, together with the ecological safety of AD digestate from pig manure. The results showed as follows. The total solid(TS) in the pig manure decreased by 1.5%-8.7%, whereas, the Soluble Chemical Oxygen Demand(SCOD) increased by 3.9%-43.6%, with the increasing hydrothermal temperature. It infers that the hydrothermal treatment enhanced the biodegradability and hydrolysis of pig manure. Nevertheless, it was easy to produce hardly degraded substances, such as organic humic acid and fulvic acid, during the hydrothermal process of pig manure. The organic humic acids and fulvic acids in the pig manure gradually increased with the increasing hydrothermal temperature. The relative content of fulvic acids increased from 37.63% to 41.97%, when the temperature increased from 150 to 170 ℃. The cumulative biogas and methane yields were 602-677 m L/g and 350-398 ml/g, respectively, in the pig manure th

关 键 词：甲烷 沼液 猪粪 水热预处理 厌氧消化 

分 类 号：X71[环境科学与工程—环境工程]