Performance and evaluation of aerobic granular sludge in oily wastewater treatment

Abstract

a b s t r a c tOily wastewater treatment through membrane separation is remarkably effective, but the high operation cost and poor resource recovery potential of this method necessitate the application of an integrated physical/chemical-biological oily wastewater treatment. In this study, aerobic granular sludge was applied for oily wastewater treatment from the ultrafiltration (UF) effluent of a twostage UF-reverse osmosis process. The removal efficiencies of the sludge for oil and chemical oxygen demand reached 94.1% and 85.6%, respectively. The protein concentration of extracellular polymeric substances (EPS) increased to 34.6 mg/g MLSS, and the relatively high protein/polysaccharide ratio was found to be closely related to the formation of aerobic granular sludge. In addition, protein in loosely bound-EPS was converted to tightly bound-EPS (TB-EPS), which indicated that the protein in TB-EPS could be the major factor affecting the granulation process. Separate sludge incineration could be achieved due to the lower heating value of granules was as high as 8.5 MJ/kg. Furthermore, the proposed process could enhance the treatment efficiency of the sludge incinerator and increase the amount of heat energy that could be recycled.

Correlation of extracellular polymeric substances and microbial community structure in denitrification biofilm exposed to adverse conditions

“…However, the PN content in R2 was higher than that in R1 after 15 consecutive days of operation due to a relatively low protein degradation rate (Vu et al ., 2009). Moreover, the PN/PS ratio was higher in R2 than in R1, R3 and R4, which implied that the stabilization of the denitrification biofilms in R2 was enhanced by the adhesion of cells through a polymeric matrix (Adav et al ., 2008; Wang et al ., 2017b). The PS and PN contents from TB‐EPS in R4 were significantly lower than that in R1 because the biosynthesis rate was severely inhibited at low temperature.…”

Change the original microbial community structure in the hydrolysis acidification tank to enhance the COD removal performance of oily wastewater

“…If they are not treated, they can be discharged arbitrarily, which is extremely harmful to soil, aquatic organisms, human health and crop growth. (Cabezas et al 2020), the treatment of oily wastewater has become an urgent environmental issue in China (Desilva 2015).Various oily wastewater treatment technologies have been developed, the hydrolytic acidification-aerobic biological treatment process is considered an important link in the treatment of oily wastewater, which converts the insoluble organic matter in the original oily wastewater into dissolved organic matter, the soluble organic matter is absorbed and utilized by the hydrolytic acidifying bacteria, which ultimately improves the biodegradability of oily sewage to facilitate subsequent aerobic treatment (Koo et al 2016;Wang et al 2017). The diversity and structure of the microbial flora in the hydrolysis acidification tank has a significant impact on the conversion of the refractory organic matter in the oily sewage into the easily degradable organic matter.…”