Over 90% of microplastics that enter wastewater treatment plants end in the wasted activated sludge. The effect of microplastic abundance on the activated sludge anaerobic digestion has been rarely reported. This study investigated the methane production performance during anaerobic digestion with different abundance of microplastic doses (0, 1,000, 3,000, 6,000, 10,000, 30,000, 60,000, 100,000 and 200,000 polyester particle/kg activated sludge). The methane production was reduced to 88.53 ± 0.5%, 90.09 ± 1.2%, 89.95 ± 4.7%, 95.08 ± 0.5%, 90.29 ± 0.5%, 93.16 ± 0.8%, 92.92 ± 1.3%, and 92.72 ± 0.6% as compared with control after digestion for 59 days. The methane production of all conditions was fitted with the logarithm model (R2 > 0.95) and one-substrate model (R2 > 0.99). The predicted and actual methane production values of digestion for 59 days had high correlation in all conditions with R2 > 0.95. The analysis based on the biochemical methane potential test model indicated that the methane production potential (B0) and hydrolysis coefficient (k) decreased at nearly all tested conditions. The reactor digestate with microplastics retained higher organic matter and nutrient concentration and had slightly lower dewaterability than the control. The inhibition of methane production potential could be attributed to the incomplete digestion with the existence of microplastics. The microbial community showed no significant difference with and without microplastics.

中文翻译：

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微塑料对废活性污泥厌氧消化的影响。

进入废水处理厂的微塑料中有90％以上是浪费的活性污泥。很少有关于活性污泥厌氧消化中微塑性丰度的影响的报道。这项研究调查了厌氧消化过程中不同微剂量（0、1,000、3,000、6,000、10,000、30,000、60,000、100,000和200,000聚酯颗粒/ kg活性污泥）的甲烷生产性能。与对照相比，甲烷产量降低到88.53±0.5％，90.09±1.2％，89.95±4.7％，95.08±0.5％，90.29±0.5％，93.16±0.8％，92.92±1.3％和92.72±0.6％消化59天后。所有条件下的甲烷产量均符合对数模型（R2> 0.95）和单底物模型（R2> 0.99）。在所有条件下，R2> 0.95时，预计的59天消化甲烷产量和实际甲烷产量值具有高度相关性。基于生化甲烷潜力测试模型的分析表明，在几乎所有测试条件下，甲烷生产潜力（B0）和水解系数（k）均下降。用微塑料消化的反应器保留了较高的有机物和营养物浓度，并且脱水性比对照低。甲烷产生潜能的抑制可归因于存在微塑料而导致的不完全消化。有和没有微生物，微生物群落均无显着差异。基于生化甲烷潜力测试模型的分析表明，在几乎所有测试条件下，甲烷生产潜力（B0）和水解系数（k）均下降。用微塑料消化的反应器保留了较高的有机物和营养物浓度，并且脱水性比对照低。甲烷产生潜能的抑制可归因于存在微塑料而导致的不完全消化。有和没有微生物，微生物群落均无显着差异。基于生化甲烷潜力测试模型的分析表明，在几乎所有测试条件下，甲烷生产潜力（B0）和水解系数（k）均下降。用微塑料消化的反应器保留了较高的有机物和营养物浓度，并且脱水性比对照低。甲烷产生潜能的抑制可归因于存在微塑料而导致的不完全消化。有和没有微生物，微生物群落均无显着差异。甲烷产生潜能的抑制可归因于存在微塑料而导致的不完全消化。有和没有微生物，微生物群落均无显着差异。甲烷产生潜能的抑制可归因于存在微塑料而导致的不完全消化。有和没有微生物，微生物群落均无显着差异。