Pretreatment of municipal sludge has the potential to improve anaerobic digestion by increasing the ultimate biodegradability of particulate chemical oxygen demand (PCOD) to methane (CH₄) gas. However, the effect of pretreatment, that is, increased soluble COD from solubilization of PCOD, makes it difficult to correctly estimate hydrolysis kinetics in biochemical methane potential tests. In this study, batch digestion tests were used to evaluate the general impact of alkaline and thermal pretreatment of waste activated sludge (WAS) and to determine a different method to estimate hydrolysis rates from pretreated streams. Throughout the 60-day batch experiments, liquid and gas samples were collected and analyzed for total (TCOD) and semi-soluble (SSCOD) COD, total (TSS) and volatile (VSS) suspended solids, pH, volatile fatty acids (VFAs), and ammonium concentration. Pretreatments significantly decreased VSS concentrations at the start of digestion, but all samples showed similar VSS destruction to the control at the end of the experiments. Ultimate CH₄ production was significantly increased by alkaline and thermal pretreatments, which produced 203 and 219 mL CH₄ gVSS⁻¹, respectively, versus 175 mL CH₄ gVSS⁻¹ in the control. Although CH₄ generation was a good proxy for solids hydrolysis of untreated WAS, CH₄ generation significantly overestimated the rate of hydrolysis of pretreated solids. The overestimation was due to the abundance of SSCOD available at the start of the experiment being converting to CH₄. Incorporating SSCOD or VFAs into the hydrolysis kinetics resulted in much slower hydrolysis rates that were similar to those measured by VSS destruction directly (e.g., 0.08 d⁻¹ with SSCOD + CH₄ vs. 0.19 d⁻¹ from CH₄ alone for thermal pretreatment vs. 0.05 d⁻¹ with VSS alone). The slower kinetics indicate that the necessity to understand the trade-offs between the performance advantages of pretreatment (i.e., solids destruction and energy conversion) versus the operational and financial impacts on large-scale digestion.

中文翻译：

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什么是合适的利率？确定厌氧消化过程中预处理废物活性污泥的消化动力学

市政污泥的预处理有可能通过提高颗粒化学需氧量 (PCOD) 对甲烷 (CH _{4 ) 的最终生物降解能力来改善厌氧消化}） 气体。然而，预处理的效果，即 PCOD 的溶解增加了可溶性 COD，使得在生化甲烷电位测试中难以正确估计水解动力学。在这项研究中，分批消化测试用于评估废活性污泥 (WAS) 的碱性和热预处理的一般影响，并确定一种不同的方法来估计预处理流的水解速率。在 60 天的批次实验中，收集液体和气体样品并分析总 (TCOD) 和半可溶性 (SSCOD) COD、总 (TSS) 和挥发性 (VSS) 悬浮固体、pH、挥发性脂肪酸 (VFA) , 和铵浓度。预处理显着降低消化开始时的 VSS 浓度，但在实验结束时，所有样品都显示出与对照相似的 VSS 破坏。终极 CH碱性和热预处理显着增加了_{4的产量，这分别产生了 203 和 219 mL CH 4} gVSS ^-1，而对照中产生了 175 mL CH ₄ gVSS ^-1。尽管 CH ₄生成是未处理的 WAS 固体水解的良好代表，但 CH ₄生成显着高估了预处理固体的水解速率。高估是由于在实验开始时大量可用的 SSCOD 正在转化为 CH ₄。将 SSCOD 或 VFA 纳入水解动力学会导致水解速率慢得多，这与直接通过 VSS 破坏测量的相似（例如，0.08 d^-1与 SSCOD + CH ₄对比 0.19 d ^-1来自单独的 CH ₄进行热预处理对比 0.05 d ^-1与单独的 VSS）。较慢的动力学表明有必要了解预处理的性能优势（即固体破坏和能量转换）与对大规模消化的运营和财务影响之间的权衡。