Advances in Environmental Technology
Volume:7 Issue: 2, Spring 2021

Crude oil contaminated soil has posed major environmental problems in recent years. Hence, this work was designed to evaluate the potential of microorganisms isolated from crude oil contaminate soil, to degrade hydrocarbon. Samples of crude oil contaminated soil were collected from Warri Refining and petrochemical Company in Delta State and characterized using standard microbiological procedure. Isolates were assayed for their ability to degrade hydrocarbon using mineral salt medium containing crude oil as source of carbon. Soil samples were treated as follows: A – untreated/control soil plus sterile crude oil, B – untreated soil plus crude oil and carrier, C – treated soil (with Enterobacter aerogenes) plus crude oil and carrier, D – treated soil (with Actinomycetes) plus crude oil and carrier, E – treated soil (with Enterobacter aerogenes and Actinomycetes) plus crude oil and carrier. After 14 days treatment, A had no growth while B, C, D and E had bacterial count of 2.6 x104 cfu/g, 7.68x1011, 1.42x1012 and 1.96x102 cfu/g respectively. At the end of 28 days period, A, B, C, D and E had count of 1.2 x 103cfu/g, 5.22 x 1011cfu/g, 9.30 x 1014cfu/g, 1.79 x1017cfu/g and 2.52 x.1019 cfu/g respectively. Serratia marcescens, Actinomycetes and Enterobacter aerogenes showed crude oil reduction of 44.3 %, 79.26 % and 61.69 % respectively. The results showed that Actinomycetes had the highest reduction rate of hydrocarbon content of soil more than other bacterial isolates.

In this work, the auto solution combustion method was used to prepare p-CuO/n-CeO2ZrO2 with different concentrations of p-CuO, which was found to be an effective photocatalyst for degrading azo dye under visible light irradiation. To investigate the photocatalytic activity of p-CuO/n-CeO2ZrO2, nonbiodegradable azo dyes such as acid orange 7 (AO7) were chosen as the modal target. The catalyst was characterised using X-ray diffraction (XRD), EDS, SEM, XPS, BET, and UV-vis DRS. Under visible light irradiation, AO7 solution easily mineralized with existing p-CuO/n-CeO2ZrO2. Experiments were carried out to determine the adsorption potential of acid orange 7 on p-CuO/n-CeO2ZrO2 at different pH values. Using some radical scavengers to evaluate intermediates, a potential degradation pathway for photocatalytic degradations has been proposed. Under similar visible light conditions, the photodegradation rate of this azo dye catalysed by p-CuO/n-CeO2ZrO2 is much faster than that of n-type CeO2ZrO2. The photocatalytic activity of the sample with a p-n CuO/ CeO2-ZrO2 molar ratio of 0.021 was 35% higher than that of n-type CeO2ZrO2. The impact of pH on photocatalytic activity of the photocatalyst was also studied. At a pH of 3, acid orange 7 showed the most degradation.

Landfills are intended for the management and disposal of municipal solid waste, which produces high volumes of leachate. The complex nature of the landfill leachate leads to various serious problems regarding water quality and human health. Hence, landfill effluents need to be treated before discharge to foul sewers or natural resources to reduce their negative effects and to comply with regulatory standards. The present study focuses on both biological and physical treatments of leachate from a controlled landfill created in Fez, Morocco, using a sequential batch reactor (SBR) coupled with a filtration system. The filtering material was characterized by scanning electron microscopy (SEM). The results obtained show that the latter has a great capacity in the treatment of the effluent. Also, for leachate, high-performance liquid chromatography coupled with ultra-violet (HPLC-UV) indicated the presence of detergent, which led to the formation of foam. Many parameters such as temperature, pH, and cycle time were also considered for their effect on the treatment. The results demonstrated the reliability and the high performance of the developed treatment system as it allowed a total elimination of BOD5, 98% of the COD, a removal rate of 100% for NH4, 78% for NO2-, and 84% for NO3-. Besides, this treatment system seemed able to eliminate fecal contamination and pathogenic germs. Thus, the present sequential batch reactor proved efficacy for landfill leachate treatment on a pilot scale design, promoting its development for a properly designed and implemented full-scale commercial product.

In this study, the activated carbon powder treated on the natural cotton fibers by a solvo-thermal method. Acetone and hydrazine used as solvent. The porous, low cost and hydrocarbon loving adsorbents obtained. Ultrasonic waves applied for homogeneous distribution of powder. Adsorbent characterization performed by FTIR and SEM analysis. Batch adsorption experiments carried out to remove the spill of motor engine oil on the water. Adsorption, desorption and reuse of the adsorbent were done in 5 steps. The highest adsorption capacity was 40.2 g/g. After 5 replicate of adsorbent reuse, the adsorption efficiency and recovery percentage were about 90%. Continuous experiments performed by 500 ml of two petrochemical and refinery wastewater samples with 2 g of adsorbent at two different flowrates. The results showed that removal percentage of oil achieved to 96%, in the inlet concentration less than 40 g oil per each gram of adsorbent. By increasing the amount of inlet oil above 40 g/g, the adsorption efficiency decreased. For these wastewater, by increasing the amount of adsorbent from 2g to 3 g, the oil pollution was completely absorbed. Therefore, this composite with acceptable performance can use for spill remove and continuous removal of oil pollutions from water and wastewater

The study investigated the source, geochemical spreading and risks assessment of trace metals in particulate matter 2.5 (PM2.5) within a gas flaring area in Bayelsa State, Nigeria. PM2.5 was measured using Geintek Particulate matter sampler APM131 monitor. Seven locations within 3000 m of the gas flaring area were sampled, with a control location established at about 7000 m from flare stark. The trace metals trapped in the PM2.5 were analyzed using flame atomic absorption spectrometry. The mean level of trace metals ranged from 2.75 – 7.56 µg/m3, 0.03 – 2.82 µg/m3, 0.16 – 1.11 µg/m3, 0.32 – 1.02 µg/m3, 1.32 – 3.34 µg/m3, and 0.15 – 2.07 µg/m3 for iron, manganese, nickel, lead, zinc and vanadium, respectively. There was statistical dissimilarity (P < 0.05) across study stations for nickel, iron and zinc, and no significant variation (P>0.05) for manganese, vanadium and lead. Pollution indices and index of geoaccumulation showed low to moderate contamination. The overall risk index reveals a low hazard. The enrichment factor and principal components analysis showed the metals are from anthropogenic and natural sources. Zinc correlates strongly with iron, manganese and nickel, an indication that these metals are from similar sources. The carcinogenic and non - carcinogenic hazards were within the threshold limits of 10-6 to 10-4 and <1, respectively. Based on the result, there are no hazardous health effects resulting from the inhalation of trace metals in PM2.5 for the age bracket being studied. However, there is a need to constantly monitor the level of these metals in the air via routine emission monitoring to forestall possible health risks.

Wastewater reclamation involving a sequencing batch reactor (SBR) has received more attention recently due to its high nutrient removal efficiency, cost-effectiveness, and low footprint. This study attempts to develop a stable and applicable activated sludge SBR for simultaneous carbon and nutrient removal from industrial wastewater. The derived-filed data were explored by response surface methodology (RSM) to identify the impact of operational variables on the SBR performance. Optimum conditions were obtained at 4000 mg/L MLSS, 100: 8: 2 COD: N: P ratio, 40 min/h aeration time, and 40 h cycling time, which resulted in the removal of 82.53% chemical oxygen demand (COD), 89.83% TKN, 87.23% PO43--P, and 73.46% NO3--N. Moreover, the sludge volume index (SVI) and mixed liquor volatile suspended solids (MLVSS)/mixed liquor suspended solids (MLSS) ratio were 64.8 mL/g and 0.8, respectively. The maximum nitrification rate was calculated as 113.9 mg/L.d, which increased with the rise of the initial ammonium concentration. The specific denitrification rate (SDNR) was estimated in the range of 0.003-0.07 mgNO3--N/mg MLVSS.d, depicting the high potential of the SBR reactor to eliminate nitrate by granular sludge. Accordingly, the removal efficiency of the optimized system revealed a notable capability towards meeting environmental regulations.