Effects of dissolved oxygen on performance and microbial community structure in a micro-aerobic hydrolysis sludge in situ reduction process

The nitrogen removal and sludge reduction performance of a multi‐stage anoxic/oxic (A/O) biofilm reactor

“…Firmicutes are a phylum of microorganisms involved in anaerobic digestion and hydrolysis (Yonglei et al, 2018), accounting for 3.3% of the aerobic region, the appearance of these two kinds of microorganisms indicates the occurrence of sludge decay to a certain extent. In addition, Nitrospirae produce microbial conditions necessary for the nitrification reaction and has a relative abundance of 6.2% in the aerobic zone and is nearly 20 times lower in the anoxic zone (0.3%), which is consistent with previous studies (Tianhao et al, 2016). The structural differences between two microbial communities at the genus level were further analyzed, as shown in Figure 10b.…”

“…The second and third phylum-level microorganisms in the anoxic region were Bacteroidetes (10.2%) and Planctomycetes (7.3%), while in the aerobic region, the trend was reversed for Planctomycetes (10.6%) and Bacteroidetes (9.0%), Bacteroidetes can efficiently decompose EPS and other macromolecule organic compounds and increase the decomposition and metabolism of pollutants, thereby achieving the purpose of EDITOR'S CHOICE-RESEARCH ARTICLE sludge reduction (Yonglei et al, 2018). Chloroflexi is a major phylum-level microorganism that degrades carbohydrates and cellular matter (Tianhao et al, 2016), accounting for 5.1% and 2.2% in anoxic and aerobic regions, respectively.…”

Evaluation of sludge reduction of three metabolic uncouplers in laboratory-scale anaerobic–anoxic–oxic process

“…With stricter environmental regulations and increasing wastewater quantity, the production of sewage sludge is expected to continuously increase (Guo et al 2014b). Owing to the large volume and high cost of sludge treatment and disposal, the production of sludge has become a serious issue for numerous wastewater treatment plants (WWTPs) worldwide (Cho et al 2012;Guo et al 2013;Niu et al 2016). Therefore, sludge production in biological wastewater treatment processes should be reduced.…”

Simultaneous removal of phosphorus and dissolved organic matter from a sludge in situ reduction process effluent by coagulants

“…During the SIR process, dissolved organic matter (DOM) is released from cell lysis and hydrolysis of particulate organic substances and then utilized by denitrifying biomass to improve nitrogen removal in both ASSR 7,8 and the SPRAS system with a micro-aerobic tank and a settler for sludge reduction. 9 The SIR process decreases the discharged amount of WAS, but it has been reported to hinder the removal of biological phosphorus, [8][9][10][11] whose concentration depends on the amount of phosphorus-accumulating organisms discharged with WAS; furthermore, an increased amount of DOM in the effluents obtained by SIR has been reported, which is attributed to the release of secondary substrates aer sludge reduction. 7 DOM in the effluent is a heterogeneous mixture of various organic substances consisting of non-biodegradable soluble organic matter from inuent wastewater and refractory soluble microbial products derived from pollutant degradation and sludge reduction.…”

“…This system performed well for pollutant removal and sludge reduction. 9,16,17 A detailed characterization of the DOM following the coagulation treatment was carried out by three-dimensional excitation-emission matrix (EEM) uorescence spectroscopy and gel permeation chromatography (GPC). Parallel factor analysis (PARAFAC) was employed to decompose EEM into individual uorescent components, which were then correlated with DOM indices to elucidate the DOM removal mechanism by coagulation.…”