Impacts of produced water origin on bacterial community structures of activated sludge

Abstract

The purpose of this study was to reveal how activated sludge communities respond to influent quality and indigenous communities by treating two produced waters from different origins in a batch reactor in succession. The community shift and compositions were investigated using Polymerase Chain Reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and further 16S ribosomal DNA (rDNA) clone library analysis. The abundance of targeted genes for polycyclic aromatic hydrocarbon (PAH) degradation, nahAc/phnAc and C12O/C23O, was tracked to define the metabolic ability of the in situ microbial community by Most Probable Number (MPN) PCR. The biosystem performed almost the same for treatment of both produced waters in terms of removals of chemical oxygen demand (COD) and PAHs. Sludge communities were closely associated with the respective influent bacterial communities (similarity > 60%), while one sludge clone library was dominated by the Betaproteobacteria (38%) and Bacteriodetes (30%) and the other was dominated by Gammaproteobacteria (52%). This suggested that different influent and water quality have an effect on sludge community compositions. In addition, the existence of catabolic genes in sludge was consistent with the potential for degradation of PAHs in the treatment of both produced waters.

Emerging Trends in Biological Treatment of Wastewater From Unconventional Oil and Gas Extraction

“…Pseudomonas, Ochrobactrum, Corynebacterium and Burkholderia were major bacterial groups identified from the reactor sludge using a Biolog Microlog TM System. Wang et al (2015) treated PW from two different Chinese oilfields sequentially using AS and reported effective (72%) COD removal maintained with a change in PW source but accompanied by shifts in microbial community. In another study, two bench-scale (3.6L) Aerobic Granular Sludge based SBRs were seeded with sludge from the aeration tank of a plant treating highly saline wastewater (Zhang et al, 2018a).…”

Iodidimonas, a bacterium unable to degrade hydrocarbons, thrives in a bioreactor treating oil and gas produced water

“…Produced water (PW), the wastewater generated as a byproduct of oil and gas extraction, contains a wide variety of contaminants such as hydrocarbons and other organic compounds, salts, heavy metals and radionuclides (1)(2)(3)(4)(5)(6)(7). Biological pretreatment of PW has been shown to be effective in removal of organic contaminants (8)(9)(10)(11)(12)(13)(14)(15)(16)(17). Specifically, hybrid physical and biological treatment systems like membrane bioreactors (MBRs) are gaining interest due to their modularity, low energy demand, and ability to retain biomass in the reactor (18) to catalyze removal of organic contaminants with minimal biofouling.…”

“…5,1,2,3,4,6,8,10,12,16, and 20% (w/v) NaCl. pH tests were conducted on R2A media amended with 3% (w/v) NaCl and appropriate buffers to create pH levels in the range of 3.4-9.16.…”