pH值对餐厨垃圾厌氧发酵产挥发性脂肪酸的影响

中国环境科学2013,33(4)：680~684ChinaEnvironmentalSciencepH值对餐厨垃圾厌氧发酵产挥发性脂肪酸的影响张玉静1,蒋建国1,2*,王佳明1(1.清华大学环境学院,北京100084；2.固体废物处理与环境安全教育部重点实验室,北京100084)摘要：通过间歇实验研究了中温条件下pH值对餐厨垃圾厌氧发酵产挥发性脂肪酸(VFA)的影响.考察了pH值为5.0、6.0、7.0及不控制pH值下的有机酸浓度及组成情况.结果表明,当控制反应器中pH值为6.0时,餐厨垃圾水解酸化效果最好,比其他pH值条件下产生更多的有机酸.pH值为6.0时,VFA浓度与单位VS产酸量在第68h达到最大值,分别为40.89g/L和0.328gVFA/gVS,是不控制pH值时的8倍.pH值对发酵产物组成影响显著.不控制pH值时,反应器内的pH值在24h内由6.6迅速下降到3.8,乙醇为主要的发酵产物,占59.8%,表现为典型的乙醇型发酵.当控制pH值为5.0、6.0、7.0时,均为丁酸型发酵.但pH值为5.0时,乙酸为主要产物;pH值为6.0时,丁酸为主要产物;pH值为7.0时,乙酸与丁酸比例相当.试验表明,餐厨垃圾厌氧发酵产酸的最佳pH值为6.0.关键词：酸化；VFA；餐厨垃圾；pH值中图分类号：X705文献标识码：A文章编号：1000-6923(2013)04-0680-05EffectofpHvalueonVFAconcentrationandcompositionduringanaerobicfermentationofkitchenwaste.ZHANGYu-jing1,JIANGJian-guo1,2*,WANGJia-ming1(1.SchoolofEnvironment,TsinghuaUniversity,Beijing100084,China；2.KeyLaboratoryforSolidWasteManagementandEnvironmentSafety,MinistryofEducation,Beijing100084,China).ChinaEnvironmentalScience,2013,33(4)：680~684Abstract：Undermesophilicconditions(35℃),batchexperimentswerecarriedouttodeterminetheeffectofpHvalueonvolatilefattyacid(VFA)concentrationandcompositionduringanaerobicacidogenesisofkitchenwastes.ThepHvaluewasuncontrolledinonereactorandcontrolledat5.0,6.0,7.0inotherreactors.TheresultsshowedthatthegreatestdegreeofhydrolysisandacidogenesiswasobtainedandmoreorganicacidwasproducedwhenthepHvaluewascontrolledat6.0.WhenthepHvaluewascontrolledat6.0,themaximumVFAconcentrationandyieldsof40.89g/Land0.328gVFA/gVSwasobtainedinthe68thhour,andwas8timesofthatwhenthepHvaluewasnotcontrolled.TheproductcompositionintheacidreactorstronglydependedonthepHvalue.ThepHvalueoftheuncontrolledreactordroppedfrom6.6to3.8quicklywithin24hours.Ethanolwasthemainproduct,accountedfor59.8%oftotalendproducts.Sothetypicalethanol-typefermentationoccurredwhenthepHvaluewasnotcontrolled.Itwasbutyricacid-typefermentationwhenthepHvaluewascontrolledat5.0,6.0and7.0.AceticacidwasmainproductatpH5.0,butyricacidwasdominantatpH6.0,proportionofaceticacidandbutyricacidwassimilartoeachotheratpH7.0.Theop