废白土热解残渣强化炼化剩余污泥水热液厌氧产能

Enhancement of anaerobic digestion of refinery excess sludge hydrothermal liquid by pyrolytic residue of spent bleaching earth

水热处理可以改善剩余污泥的脱水性能,提高减量化效果,副产的水热液含有高浓度有机物,可通过厌氧消化来回收能源。针对炼化剩余污泥水热液厌氧消化甲烷产率低的问题,并基于“以废治废”理念,开展了利用含油废白土热解残渣强化水热液厌氧消化产能的实验研究。结果表明,热解残渣(400 mg/L)可明显促进水解功能,CHO和CHNO类大分子有机物(分子质量>450 u)被有效降解;产酸性能被强化,挥发性脂肪酸(VFA)产率提高100%,质量浓度达到683 mg/L;厌氧消化的甲烷产率得以提升,每克COD的甲烷产量最高可达270 mL,较空白组提高了54%,伴随回收氢气137 mL/g。含油废白土热解残渣具有多孔结构,可为微生物附着提供位点,因此富集了Clostridium、Syntrophorhabdus等水解酸化细菌和Methanosaeta、Methanobacterium、Methanospirillum等产甲烷古菌。同时,其含有的金属元素可促进功能酶合成,并促进种间电子传递,使古菌可直接接收细菌产生的电子及H+并还原CO_(2)产生甲烷,从而提高了甲烷产率。该研究结果可为炼化固废资源化利用和能量回收提供一定理论参考。

Hydrothermal treatment can improve the dewaterability and enhance the reduction effect of excess sludge.Hydrothermal liquid contains high concentration of organic matter,which can be converted into biogas for energy recovery through anaerobic digestion.Based on the concept of waste control by waste,pyrolytic residues of spent bleaching earth was used to enhance the anaerobic digestion capacity of hydrothermal liquid,to address the problem of low methane yield from anaerobic digestion of refinery excess sludge.The results showed that the pyrolysis residue(400 mg/L)could significantly promote the hydrolysis function,and macromolecular organic matters(molecular weight>450 u),especially CHO and CHNO were effectively degraded.Acid production was enhanced,and yield of volatile fatty acid(VFA)was increased by 100%with a mass concentration of 683 mg/L.The methane yield of anaerobic digestion was enhanced.The methane yield per gram of COD was up to 270 mL,which was 54%higher than that of blank group,accompanied by the recovery of 137 mL/g of hydrogen.The pyrolytic residues of spent bleaching earth has a porous structure that provides sites for microbial attachment,thus enriching hydrolytic acidifying bacteria such as Clostridium and Syntrophorhabdus and methanogens such as Methanosaeta,Methanobacterium and Methanospirillum.The metal elements pyrolysis residues contains can promote functional enzyme synthesis and interspecies electron transfer,so that methanogens can directly receive electrons and H+produced by bacteria and reduce CO_(2) to produce methane,thus improving methane yield.It can provide some theoretical reference for the resource utilization and energy recovery of refining and chemical solid waste.