Long-term biodegradation of aged saline-alkali oily sludge with the addition of bulking agents and microbial agents

Abstract

Huge amount of aged oily sludge was generated during the drilling and transportation of crude oil. Sometimes, the sludge exhibited characters of combined pollution, such as saline-alkali oily sludge. Orthogonal experiments of L16(45) were conducted to evaluate the long-term effects of total petroleum hydrocarbons (TPH) concentration, microbial agents (Oil Gator and ZL) and bulking agents (peat and wheat bran) on the biodegradation of aged saline-alkali oily sludge. Compared with the control group, the significant improvement in the removal rate of TPH was exhibited with the addition of microbial agents and bulking agents after 231 days of the experimental period. Based on the values of mean range (R), it was revealed that the predominant influencing factor of the bioremediation was TPH concentration. After biostimulation and bioaugmentation, the quantity of petroleum hydrocarbon-degrading bacteria in the oily sludge increased by 2–4 orders of magnitude. Furthermore, the bioremediation improved the microbial diversity based on the analysis of PCR-DGGE. It was inferred that the addition of microbial agents and bulking agents reconstructed the microbial ecological niche. The principal component analysis indicated that the differentiation of the microbial community was generated by the biostimulation and bioaugmentation in comparison with the control samples.

Unravelling the genetic and functional diversity of dominant bacterial communities involved in manure co-composting bioremediation of complex crude oil waste sludge

“…These properties make them less amenable to biodegradation and are thus recalcitrant in the environment under normal conditions. Additionally, COWS and its components are substantially cytotoxic, mutagenic and carcinogenic, especially polycyclic aromatic hydrocarbons (PAHs) [1,2]. Environmental pollution with COWS has also been linked to physical and chemical changes of natural habitats, with potential lethal and sub-lethal toxic effects on aquatics and terrestrial ecosystem [3].…”