Treatment of petroleum refinery wastewater containing heavily polluting substances in an aerobic submerged fixed-bed reactor

Treatment of petroleum refinery wastewater containing heavily polluting substances in an aerobic submerged fixed-bed reactor

Type	Journal Article
Author	S. Vendramel
Author	J. P. Bassin
URL	http://dx.doi.org/10.1080/09593330.2015.1019933
Volume	36
Issue	16
Pages	2052-2059
Publication	Environmental Technology
Date	August 18, 2015
Abstract	Petroleum refineries produce large amount of wastewaters. Some of these constituents may be recalcitrant difficult to treat biologically. Researchers evaluated the capability of an aerobic submerged fixed-bed reactor (ASFBR) containing a corrugated PVC support material for biofilm attachment to treat a complex and high-strength organic wastewater coming from a petroleum refinery. The reactor operation was divided into five experimental runs which lasted more than 250 days. During the reactor operation, the applied volumetric organic load was varied within the range of 0.5–2.4 kgCOD.m−3.d−1. Despite the inherent fluctuations on the characteristics of the complex wastewater and the slight decrease in the reactor performance when the influent organic load was increased, the ASFBR showed good stability and allowed to reach chemical oxygen demand, dissolved organic carbon and total suspended solids removals up to 91%, 90% and 92%, respectively. Appreciable ammonium removal was obtained. Some challenging aspects of reactor operation such as biofilm quantification and important biofilm constituents  were also addressed in this work. Average PS/volatile attached solids (VAS) and PT/VAS ratios were around 6% and 50%, respectively. The support material promoted biofilm attachment without appreciable loss of solids and allowed long-term operation without clogging. Microscopic observations of the microbial community revealed great diversity of higher organisms, such as protozoa and rotifers, suggesting that toxic compounds found in the wastewater were possibly removed in the biofilm.