Optimization Design and Experimental Study of Two‐Phase Integrated Sludge Thickening and Digestion Reactor

Abstract

In this study, FLUENT software was used to simulate the flow regime of an integrated sludge thickening and digestion reactor. To optimize the flow regime, the combinational effect of key parameters of the reactor structure was investigated with an L16 (4(5)) orthogonal test. The reactor was then redesigned based on the optimization results, and a series of experiments was conducted to study the treatment effect with sludge dosage rates of 12, 18, 24, and 30%. The operation results showed that the reactor obtained the best treatment efficiency when the sludge dosage rate was 24%. At this dosage, the water content of the sludge decreased from 99.1% to 91.8%, with organic matter content (volatile solids [VS]/total solids) decreasing to 21.2% and average gas production (CH4 62.66%, CO2 11.56%, N2 23.91%, O2 1.59%) reaching 231.3 L/kg VS. Therefore, the results implied that the optimized reactor has good effects on sludge thickening and digestion.

A comprehensive review of anaerobic digestion of organic solid wastes in relation to microbial community and enhancement process

“…103,104 In fact, acetoclastic methanogens were more sensitive to inhibitors such as free ammonia, VFAs, and excess metallic ion concentrations. For example, Hu et al 105 applied the Chao1 index to indicate the diversity of Methansarcina, which decreased from 0.57 to 0.21 when concentrations of NH 3 -N increased from 0.15 mol L −1 to 0.30 mol L −1 . Furthermore, when the amount of K + was varied from 1.2 × 10 −2 mol L −1 to 4.8 × 10 −2 mol L −1 , the Chao1 index for Methanosaeta was 0.53 and 0.37, respectively.…”

“…In fact, acetoclastic methanogens were more sensitive to inhibitors such as free ammonia, VFAs, and excess metallic ion concentrations. For example, Hu et al . applied the Chao1 index to indicate the diversity of Methansarcina, which decreased from 0.57 to 0.21 when concentrations of NH 3 ‐N increased from 0.15 mol L −1 to 0.30 mol L −1 .…”