Abstract: Environment free of pollutants should be the concern of every individual but with industrialization and urbanization it is difficult to achieve. In view of achieving a pollution limited environment at low cost, a study was conducted on the use of bioremediation technology to remediate hydrocarbons and three heavy metals namely; copper (Cu), zinc (Zn) and iron (Fe) from a typical petroleum refinery wastewater in a closed system. Physicochemical and microbiological characteristics on the wastewater sample revealed that it was polluted with the aforementioned pollutants. Isolation and identification of microorganisms present in the wastewater sample revealed the presence of Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus and Staphylococcus epidermidis. Bioremediation experiments carried out on five batch reactors with different compositions but at same environmental conditions revealed that treatment T5 (boosted with the association of Bacillus subtilis, Micrococcus luteus) gave the best result in terms of oil and grease content removal (i.e. 67% in 63 days). In addition, these microorganisms were able of reducing the concentrations of heavy metals in the sample. Treatments T5, T3 (boosted with Bacillus subtilis only) and T4 (boosted with Micrococcus luteus only) gave optimum percentage uptakes of 65, 75 and 25 for Cu, Zn and Fe respectively.
Abstract: Anaerobic treatment has many advantages over other
biological method particularly when used to treat complex
wastewater such as petroleum refinery wastewater. In this study two
Up-flow Anaerobic Sludge Blanket (UASB) reactors were operated
in parallel to treat six volumetric organic loads (0.58, 1.21, 0.89,
2.34, 1.47 and 4.14 kg COD/m3·d) to evaluate the chemical oxygen
demand (COD) removal efficiency. The reactors were continuously
adapting to the changing of operation condition with increase in the
removal efficiency or slight decrease until the last load which was
more than two times the load, at which the reactor stressed and the
removal efficiency decreased to 75% with effluent concentration of
1746 mg COD/L. Other parameters were also monitored such as pH,
alkalinity, volatile fatty acid and gas production rate. The UASB
reactor was suitable to treat petroleum refinery wastewater and the
highest COD removal rate was 83% at 1215 kg/m3·d with COD
concentration about 356 mg/L in the effluent.
Abstract: Petroleum refineries discharged large amount of
wastewater -during the refining process- that contains hazardous
constituents that is hard to degrade. Anaerobic treatment process is
well known as an efficient method to degrade high strength
wastewaters. Up-flow Anaerobic Sludge Blanker (UASB) is a
common process used for various wastewater treatments. Two UASB
reactors were set up and operated in parallel to evaluate the treatment
efficiency of petroleum refinery wastewater. In this study four
organic volumetric loading rates were applied (i.e. 0.58, 0.89, 1.21
and 2.34 kg/m3·d), two loads to each reactor. Each load was applied
for a period of 60 days for the reactor to acclimatize and reach steady
state, and then the second load applied. The chemical oxygen demand
(COD) removals were satisfactory with the removal efficiencies at the
loadings applied were 78, 82, 83 and 81 % respectively.