蔬菜废弃物中温厌氧发酵酸化失稳预警指标筛选  

Screening of early warning indicators of instability in anaerobic digestion of vegetable waste under mesophilic condition

作　　者：陈琳[1,2] 李东[1] 文昊深[3] 冯立森 黄亚军[3] 刘晓风[1] Chen Lin Li Dong Wen Haoshen Feng Lisen Huang Yajun Liu Xiaofeng(Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China University of Chinese Academy of Sciences, Beijing 100049, China Chengdu Organic Chemicals Co. LTD., Chinese Academy of Sciences, Chengdu 610041, China Sichuan University Hi-Tech Group, Chengdu 610065, China)

机构地区：[1]中国科学院成都生物研究所,成都610041 [2]中国科学院大学,北京100049 [3]中国科学院成都有机化学有限公司,成都610041 [4]四川川大科技产业集团有限公司,成都610065

出　　处：《农业工程学报》2017年第1期225-230,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金面上项目(21476222);国家科技支撑计划课题(2015BAD21B01)

摘　　要：厌氧消化是一种可以较好地将有机废弃物处理和能源回收结合的生物技术,它是多种厌氧微生物共同参与、分阶段有序进行的复杂串联代谢过程。其中产甲烷菌对环境最敏感、代谢速率最慢,产甲烷阶段往往是厌氧消化系统的瓶颈,水解酸化与产甲烷两阶段不能较好地匹配,极易受到抑制。针对蔬菜废弃物厌氧发酵易酸化的特点,该试验旨在筛选发酵体系酸化失稳预警指标,采用自行设计的70 L反应装置,在中温35℃条件下进行蔬菜废弃物厌氧发酵的连续冲击负荷试验。通过对发酵过程中的气相及液相指标监测,该研究筛选出4类失稳预警指标,分别为:1)甲烷与二氧化碳的比值。当CH_4/CO_2<1.06时,系统出现酸化现象,提前18 d对厌氧发酵系统做出预警指示,具有最强的失稳预警性;2)挥发性脂肪酸。当丙酸、正/异丁酸、正/异戊酸出现突变时,系统出现酸化征兆,分别在17、15和15 d对厌氧消化体系做出失稳预警;3)碱度。包括总碱度(total alkalinity,TA)、碳酸氢盐碱度(bicarbonate alkalinity,BA)、及挥发酸盐碱度(intermediate alkalinity,IA)的耦合性指标,当BA<1500 mg/L、BA/TA<0.8或IA/BA>0.4时,系统提前13、12和12 d做出酸化预警指示,此时发酵体系缓冲性能较差,系统极易出现挥发性脂肪酸的累积进而导致系统酸化失稳;4)氧化还原电位和pH值在整个厌氧消化过程中均持续微弱变化,利用其绝对值很难做出失稳判断,利用其相对变化值可做出失稳判断,骤变分别发生在产气彻底停止前第5天和第4天,预警能力较弱。在工程实际应用中,相比液相指标而言,气相指标的监测更容易实现,建议CH_4/CO_2作为预警指标。Anaerobic digestion（AD） is a kind of biological technology,which can combine organic waste treatment and energy recovery together.AD is a complex and well-organized metabolic process with a series of ordered biochemical reactions participated by multiple anaerobic microorganisms.Compared to other microbes in AD process,Methanogenic archaea are most sensitive to environment and have the lowest metabolism rate,so the methanogenic stage is the bottleneck step of anaerobic digestion system.The characteristics of vegetable waste,such as high content of moisture and organic matter,make it suitable for anaerobic digestion.Vegetable wastes are easily perishable materials.It is difficult to realize the balance between hydrolysis/acidification and methanogenesis during the digestion of vegetable waste.The methanogens are easily inhibited by cumulative volatile fatty acids,especially under high organic loading rate（OLR）.Therefore,to stably running biogas plant,the digestion system with vegetable waste as substrate is always operated under low OLR.However,the lower OLR always results in a low efficiency of digester and low treatment capacity of plant.Taking into account the efficiency and stability,it is necessary to find effective instability early warning indicators and control strategies.In order to select a set of early-warning indicators for the acidification of the digestion system,continuous anaerobic digestions of vegetable waste were carried out at OLR of 0.5,1.0 and 1.5 g/（L·d） in the self-designed 70 L reactors under mesophilic conditions（35 °C）.During the digestion,the primary parameter of the gas and liquid phase were directly monitored by on-line analyzer（daily biogas production,CH_4 and CO_2 content,pH value and oxidation-reduction potential（ORP））,and off-line analytical instrument（total alkalinity（TA）,bicarbonate alkalinity（BA）,intermediate alkalinity（LA） and volatile fatty acids,including acetate,propionate,n-butyrate,iso-butyrate,n-valerate,and iso-valerate）.Seconda

关 键 词：发酵 废弃物 沼气 蔬菜 中温发酵 预警指标 

分 类 号：X712[环境科学与工程—环境工程]