Sludge production in wastewater treatment plants is increasing worldwide due to the increasing population. This work investigated the effects of ultrasonic (ULS), ultrasonic-ozone (ULS-Ozone) and ultrasonic + alkaline (ULS+ALK) post-treatments on the anaerobic digestion of sewage sludge in semi-continuous anaerobic reactors. Three conditions were tested with different hydraulic retention times (HRT, 10 or 20 days) and sludge recycle ratios (R = Q R /Q in (%): 50 or 100%). Biogas yield increased by 17.8% when ULS+ALK post-treatment was applied to the effluent of a reactor operating at 20 days HRT and at a 100% recycle ratio. Operation at 10 days HRT also improved the biogas yield (277 mL CH 4 /g VSadded (VS: volatile solids) versus 249 mL CH 4 /g VSadded in the control). The tested post-treatment methods showed 4–7% decrease in effluent VS. The post-treatment resulted in a decrease in the cellular ATP (Adenosine tri-phosphate) concentration indicating stress imposed on microorganisms in the reactor. Nevertheless, this did not prevent higher biogas production. Based on the results, the post-treatment of digested sludge or treating the sludge between two digesters is an interesting alternative to pre-treatments.
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机译：由于人口的增加，废水处理厂的污泥产量正在全球范围内增加。这项工作研究了超声（ULS），超声臭氧（ULS-臭氧）和超声+碱（ULS + ALK）后处理对半连续厌氧反应器中污水污泥厌氧消化的影响。在不同的水力停留时间（HRT，10或20天）和污泥再循环率（R = Q R / Q in（％）：50或100％）下测试了三种条件。将ULS + ALK后处理应用于在HRT运行20天且循环比率为100％的反应器的废水中，沼气产量提高了17.8％。在HRT运行10天还可以提高沼气产量（277 mL CH 4 / g VS添加（VS：挥发性固体），而对照组为249 mL CH 4 / g VS）。经过测试的后处理方法显示出水VS降低了4–7％。后处理导致细胞ATP（三磷酸腺苷）浓度降低，表明施加在反应器中微生物的压力。然而，这并不能阻止更高的沼气产量。根据结果，消化后污泥的后处理或两个蒸煮器之间的污泥的处理是预处理的有趣替代方法。
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