Understanding the mechanisms of how poly aluminium chloride inhibits short-chain fatty acids production from anaerobic fermentation of waste activated sludge

Abstract

It is generally believed that the preference ranking method PROMETHEE has a quadratic time complexity. In this paper, however, we present an exact algorithm that computes PROMETHEE's net flow scores in time O(qn log(n)), where q represents the number of criteria and n the number of alternatives. The method is based on first sorting the alternatives after which the unicriterion flow scores of all alternatives can be computed in one scan over the sorted list of alternatives while maintaining a sliding window. This method works with the linear and level criterion preference functions. The algorithm we present is exact and, due to the sub-quadratic time complexity, vastly extends the applicability of the PROMETHEE method. Experiments show that with the new algorithm, PROMETHEE can scale up to millions of tuples.

The impact of chemically enhanced primary treatment on the downstream liquid and solid train processes

“…This provided sludge cells better protection and slowed down the solubilization process. Furthermore, Chen et al (2018) verified that with the increase of PACl addition from 0 to 40 mg Al/g of total suspended solids, SCFA yield decreased from 212.2 to 138.4 mg COD/g volatile suspended solids. Kooijman, Kreuk, and Lier (2017) investigated the dewaterability of CEPT sludge and the results indicated that CEPT sludge has a shorter capillary suction time (CST) value compared to sludge without chemical addition, which is probably due to the lower fraction of small particles in the CEPT sludge (Kooijman et al, 2017).…”

“…This provided sludge cells better protection and slowed down the solubilization process. Furthermore, Chen et al () verified that with the increase of PACl addition from 0 to 40 mg Al/g of total suspended solids, SCFA yield decreased from 212.2 to 138.4 mg COD/g volatile suspended solids.…”

“…Moreover, Kim and Chung () discussed the impact on VFA production to be more severe for PACl dosages over 102 mg/L. Mechanism exploration conducted by Chen et al () to investigate the influence of PACl on short‐chain fatty acids (SCFAs) production from anaerobic waste activated sludge fermentation revealed that the addition of PACl assisted sludge floc formation and caused more EPS to remain in the sludge. This provided sludge cells better protection and slowed down the solubilization process.…”

Effect of diclofenac on the production of volatile fatty acids from anaerobic fermentation of waste activated sludge

“…Although this process is very useful in protecting natural water bodies from pollution, large amounts of waste activated sludge (WAS) are inevitably produced as the major byproduct. WAS contains high levels of pathogens, heavy metals and other toxic and hazardous substances (Chen et al, 2018; Wang et al, 2018), and therefore requires to be effectively treated before its final disposal. On the other hand, WAS contains a lot of organics such as protein and carbohydrates, which make it a valuable resource (Wang et al, 2017a(Wang et al, , 2017b.…”

Feasibility of enhancing short-chain fatty acids production from waste activated sludge after free ammonia pretreatment: Role and significance of rhamnolipid

“…Protein was measured using the Lowry's method with BSA as the standard (Lowry et al, 1951). SCFA was performed by gas chromatography, and the operation procedures were according to our previous study and detailed in Supplementary data (Chen et al, 2018). The activity of key hydrolytic enzymes (protease) and acetate-forming enzymes (acetate kinase (AK)) were measured according to previous study (Goel et al, 1971;Feng et al, 2009).…”