Chemical and Ecotoxicological Assessment of Selected Biologically Activated Sorbents for Treating Wastewater Polluted with Petroleum Products with Special Emphasis on Polycyclic Aromatic Hydrocarbons

Abstract

A chemical and ecotoxicological assessment of treatment of wastewater that had been polluted with petroleum products using only Activated Sludge (AS) and four biologically activated sorbents (BASs), consisting of activated sludge plus: coal-based activated carbon (-C1), coconut shell-based activated carbon (-C2), zeolite (-Z), and anthracite (-A) were conducted. The efficiency and robustness of the four wastewater treatment systems were evaluated by calculating the reduced total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) contents and the acute ecotoxicity of the effluents. The chemical analysis showed that the combined treatment systems were very effective for reducing the total petroleum hydrocarbon and readily bioavailable PAH contents. The most efficient systems were the BAS-C1 and -C2, which removed 60-88% and 99.5-99.6% of TPH and PAH, respectively. The activated sludge-only treatment was the least effective for purifying the wastewater. Chemical oxygen demand was reduced by >90% by all carbon-based BASs (BAS-C1, BAS-C2 and BAS-A). Shifts in the relative composition of the individual PAHs were identified in samples taken before and after treatment. Algal and bacterial bioassays showed that the toxicities of effluents following treatment by all four systems (except AS for algae) were reduced by more than 80% and 90%, respectively. However, crustacean tests indicated that the carbon-based BASs reduced the toxicity [V tox(50) ] only by 19-67%. Our results indicated that the combination of sorption and biodegradation processes have great potential in the treatment of petroleum products polluted wastewater and is less sensitive for inhibitors of the biological process than treatments in which activated sludge alone is used. The assessment of chemical and ecotoxicological endpoints provided valuable information, but contrasting results for one of the assays indicates that further analysis on the capacity of the different treatment systems is warranted.

Microbial regeneration of spent activated carbon dispersed with organic contaminants: mechanism, efficiency, and kinetic models

“…However, there are a few reports of the bioregeneration of GAC using actual industrial effluent. Augulyte et al (2008) studied the treatment of wastewater polluted with petroleum products using biologically activated sorbents. Algal and bacterial bioassays showed that the toxicities of effluents following treatment were reduced by more than 80% and 90%, respectively.…”

Multivariate analysis of a biologically activated carbon (BAC) system and its efficiency for removing PAHs and aliphatic hydrocarbons from wastewater polluted with petroleum products

“…Indications of sorption capacities for organic substances in the wastewater were rapidly and conveniently obtained using red formazan adsorption method earlier described in Augulyte et al [18].…”

“…The assays measure the amounts of intensely red 1,3,5-triphenylformazan (TF) formed via the reduction of 2,3,5-triphenyltetrazolium chloride (which are proportional to the amounts of DHA present in the samples, and thus provide proxy indicators of bioactivity; [20]). For these tests, samples of BAC were taken from well-mixed reservoirs at the same time of day and analyzed according to the method described in Augulyte et al [18].…”

“…contents of aliphatic hydrocarbons ranging from C 10 to C 40 , were determined according to the standard method [21] at the Environmental Engineering Department, Kaunas University of Technology, Lithuania. The extracts were analyzed according to Augulyte et al [18].…”

Analysis of Chemical and Toxicological Properties of Fluids for Shale Hydraulic Fracturing and Flowback Water

“…The performed toxicological tests allow simultaneous determination of harmful effects of all the substances contained in the water sample on select living organisms, taking into account interactions between all the elements of the tested system [22]. The research results are presented in toxicity units (TU):…”