A cascade of a denitrification bioreactor and an aerobic biofilm reactor for heavy oil refinery wastewater treatment

Abstract

The performance of an efficient denitrification bioreactor-aerobic biofilm reactor cascade for heavy oil refinery wastewater treatment was investigated. Optimum operation parameters for denitrification were found as follows: (1) hydraulic retention time of 8 h;(2) C/NO 3 À -N molar ratio of 3.75 with acetate as the carbon source; (3) 20% (v/v) carrier filling ratio in the denitrification bioreactor. Under such optimal conditions, a volumetric removal of 0.82 kg N m À3 d À1 was obtained. As an alternative low-cost carbon source to acetate, secondary DAF effluent (COD/NO 3 À -N mass ratio of 5.4) was also detected and a stable activity of denitrification was achieved with adding 25% volume fraction of secondary DAF effluent. Effluent COD of the subsequent aerobic biofilm reactor further decreased satisfying the requirements of the current discharge standards. High-throughput sequencing results exhibited that Rhodocyclaceae and Comamonadaceae were the dominant denitrifiers in the denitrification reactor and Pseudomonas was the dominant microbe in the aerobic biofilm reactor.

Periodic chemical cleaning with urea: disintegration of biofilms and reduction of key biofilm-forming bacteria from reverse osmosis membranes

“…2002 , Bellini et al. 2017 , Dong et al. 2019 ) and commonly reported in microbial communities in activated sludge systems ( Sadaie et al.…”

The Impact of Bioaugmentation on the Performance and Microbial Community Dynamics of an Industrial-Scale Activated Sludge Sequencing Batch Reactor under Various Loading Shocks of Heavy Oil Refinery Wastewater

“…Heavy oil refinery wastewater (HORW) contains high amounts of recalcitrant and toxic organic pollutants, such as petroleum hydrocarbons, emulsified oil, sulfur compounds, and dissolved and dispersed oil [1]. Traditional treatment of heavy oil refinery wastewater is time-consuming and expensive.…”