Department of Physics, Anna University Regional Campus, Tirunelveli, Tamil Nadu 627007, India.
Department of Life Sciences, Central University of Tamil Nadu, Neelakudi, Thiruvarur 610005, Tamil Nadu, India.
Sci Total Environ. 2022 Apr 15;817:152873. doi: 10.1016/j.scitotenv.2021.152873. Epub 2022 Jan 5.
Regardless of the issue of sludge management all over the world, the role of phase separated pretreatment prior to anaerobic digestion are more promising in terms of energy efficient biomethane production. However, the effect of phase separated pretreatment (dissociation of extracellular polymeric substances (EPS) followed by biological pretreatment in a two-step process) must be sensibly evaluated from various perceptions to consolidate its effectiveness in sludge management and bioenergy recovery. In this study, mild hydrogen peroxide induced bacterial pretreatment (HO-BP) was employed as phase separated pretreatment to investigate the effectiveness of EPS dissociation prior to biological pretreatment on sludge solubilization and biomethanation. The novelty of this study is the application of mild dosage of hydrogen peroxide at sludge pH for the removal of EPS layer with lesser formation of recalcitrant substances which thereby enhances the disintegration by enzyme secreting bacterial and methane generation. The outcome confirmed that the higher EPS dissociation was achieved at HO dosage of 8 μL per 100 mL of sludge with negligible cell lysis. An extractable EPS of 172.8 mg/L was obtained after HO treatment. The higher sCOD solubilization of 22% and the suspended solid reduction of 17.14% were achieved in hydrogen peroxide followed by bacterial pretreatment (HO-BP) as compared to of bacterial pretreatment alone (BP) (solubilization-11% and suspended solids reduction-9.3%) and control (C) sludges (solubilization-5% and suspended solids reduction-4.3%). The methane generation for HO-BP sludge is 0.174 L/gCOD which is higher than BP (0.078 L/gCOD,) and C sludge (0.02175 L/gCOD). A higher biomass solubilization and increased biomethanation in HO-BP revealed that dissociation of EPS prior to bacterial pretreatment increases the surface area for bacterial pretreatment facilitating easier accessibility of substrate and enhanced biomethanation.
无论在全球范围内面临何种污泥管理问题，相分离预处理（分两步进行胞外聚合物物质（EPS）的解离和生物预处理）在提高能源效率生产生物甲烷方面都更具前景。然而，为了巩固其在污泥管理和生物能源回收方面的有效性，必须从多个角度合理评估相分离预处理的效果。在这项研究中，采用温和过氧化氢诱导的细菌预处理（HO-BP）作为相分离预处理，研究了生物预处理前 EPS 解离对污泥溶解和生物甲烷化的有效性。本研究的新颖之处在于在污泥 pH 值下使用温和剂量的过氧化氢去除 EPS 层，同时形成较少的难处理物质，从而增强了酶分泌细菌的分解作用和甲烷生成。结果证实，在 HO 剂量为每 100 毫升污泥 8 μL 时，可实现更高的 EPS 解离，且细胞裂解可忽略不计。经过 HO 处理后，可获得 172.8 mg/L 的可提取 EPS。与单独的细菌预处理（BP）（溶解率 11%，悬浮固体减少 9.3%）和对照（C）污泥（溶解率 5%，悬浮固体减少 4.3%）相比，过氧化氢预处理后细菌预处理（HO-BP）可实现更高的 sCOD 溶解率（22%）和悬浮固体减少率（17.14%）。HO-BP 污泥的甲烷生成量为 0.174 L/gCOD，高于 BP（0.078 L/gCOD）和 C 污泥（0.02175 L/gCOD）。HO-BP 污泥中更高的生物量溶解和增加的生物甲烷化表明，在细菌预处理前进行 EPS 解离可增加细菌预处理的表面积，从而更容易获得底物并增强生物甲烷化。
