Treatment Of Refinery Effluent Research Articles

Synthesis and characterisation ZnO/TiO2 incorporated activated carbon as photocatalyst for gas refinery effluent treatment

This study aims to optimize the ZnO/TiO2-Active carbon (AC) catalyst for utilized in the degradation of gas refinery effluent (GRE) treatment under sunlight via photocatalytic process. The incorporation of AC into ZnO/TiO2 has enhanced process efficiency and quality, resulting in heightened productivity, during GRE purification. The ZnO/TiO2-AC photocatalyst, synthesized, underwent analysis using various instruments, including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), porosity analysis using BET (Brunauer Emmett Teller), and Fourier transform infrared spectrometry (FT-IR). The experimental data were assessed to generate empirical models for analyzing on individual responses. The fitted models were statistically examined, considerably validated (via analysis of variance (ANOVA)). In the GRE treatment process, the central composite design (CCD) method was chosen to design a number of experiments. The optimal conditions for this process were determined to be a photocatalyst dosage of 0.17 g, and a sunlight exposure time of 80 min. The system's best response for GRE degradation was predicted to be 97.3 %. Overall, our findings prove that the optimized ZnO/TiO2-AC catalyst is a prominent and effective material for GRE treatment through photocatalytic process under sunlight. The method used in this research can be used as an efficient technology for solar photocatalytic degradation of discharged gas refinery effluent under the climatic conditions of most countries.

Electrooxidation using SnO2–RuO2–IrO2|Ti and IrO2–Ta2O5|Ti anodes as tertiary treatment of oil refinery effluent

AbstractIn the present work, treatability studies were carried out with oil refinery wastewater (effluent from the secondary treatment) using electrooxidation (EO) process employing two mixed oxide anodes: SnO2–RuO2–IrO2|Ti and IrO2–Ta2O5|Ti. Both electrodes' performance were compared by their capacity to generate active chlorine in a synthetic solution and organic matter mineralization of a sample with an average phenol (C6H6O) concentration of 100 mg L−1. Before degradation experiments, surface analysis, and linear sweep voltammetry tests were performed. SnO2–RuO2–IrO2|Ti anode yielded higher active chlorine, reaching an average concentration of 340 mg L−1 at 90 min of electrolysis and 25 mA cm−2. On the other hand, IrO2–Ta2O5|Ti anode only generated an average concentration of 200 mg L−1 at 90 min and 40 mA cm−2. Regarding the degradation experiments, SnO2–RuO2–IrO2|Ti anode showed the highest dissolved organic carbon removal, ranging from 26% to 40%. In addition, through a three‐dimensional excitation–emission matrix fluorescence analysis, it was possible to elucidate the degradation of C6H6O and some possible polycyclic aromatic hydrocarbons present in the effluent. The results suggested that 65%–90% of the hydrocarbons and C6H6O present in the effluent were degraded with the SnO2–RuO2–IrO2|Ti anode applying 25 mA cm−2 within the first 30 min of electrolysis, reaching almost 99% degradation at 90 min. The EO process using SnO2–RuO2–IrO2|Ti can be an alternative for tertiary treatment of oil refinery wastewater for degradation and mineralization of the remaining organic matter of secondary effluents (biological processes) via active chlorine species.

Refinery effluent water treatment: An integrated approach

This study has successfully investigated the use of an integrated approach to refinery effluent water treatment. To achieve this, a multistage system was used for the treatment of refinery effluent water from Port Harcourt Refining Company, Rivers State Nigeria. The physicochemical and microbial properties of the treated effluent water were used to assess the efficacy of the treatment process. Properties investigated include temperature, pH, chlorine content, bacterial count, chemical and biological oxygen demand, dissolved oxygen, amount of oil and grease in the water, turbidity, and the amount of metal content in the water. The results for the treated effluent water sample were pH 7.84, Turbidity 3.47NTU, Total Dissolved Solid 69.96 ppm, Total Suspended Solid 14.82 mg/L, Total salinity 29.21 ppm, Biochemical Oxygen Demand 0.65 mg/L, Chemical Oxygen Demand 1.87 mg/L, and Dissolved Oxygen 4.13 mg/L. The results showed an impact of this process on refinery effluent water treatment.

Kinetics-driven coagulation treatment of petroleum refinery effluent using land snail shells: An empirical approach to Environmental sustainability

Petroleum refinery effluent (PRE) containing a high concentration of colloidal particles causing turbidity is a point source pollutant. There is currently no baseline for the residual concentration of colloids in industrial effluent. In the present study, the performance of land snail shells (LSS) characterized using FTIR and XRD techniques used for the treatment of PRE was investigated. The effluent collected from the outlet train of the industrial facility contains 220 NTU of turbidity corresponding to 520 mg/L of colloidal particles. Analysis of the industrial effluent yielded a COD to BOD ratio > 3.5 eliminating the option of a biological method of treatment. Coagulation-flocculation treatment of the PRE was carried-out following a standard nephelometric test. To clarify the applicability of LSS beyond removal efficiency, machine learning (ML), adsorption, and coag-flocculation kinetics were applied to investigate the treatment process. The predictive capacities of the ML models were compared using statistical metrics. The synergetic effects of operating variables were equally studied. The predicted optimum operating conditions of the treatment process were pH 6, dosage of 0.1 g/L, and a settling time of 30 minutes. The pseudo-second-order and coag-flocculation kinetics result confirmed the reduction of the colloidal particles that occurred via adsorption and inter-particle bridging mechanism. The flocculation outcome proved that the mixing regime 20 s−1≤ G≤120 s−1 promoted aggregation rate over breakage coefficient transcending to 90% removal efficiency. The finding shows that the stability of the finished water corresponds to the 23 mg/L threshold of residual colloidal particles, and 10NTU, which satisfied the EPA guideline for environmentally sustainable recovery.

Design and optimization of a sequential and hybrid advanced oxidation process system using response surface methodology

Of different approaches for refinery effluent treatment, the application of Advanced Oxidation Processes (AOPs) (e.g. electro-Fenton) and nano Zero-Valent Iron (nZVI) particles have been of great interest lately. Associated constraints with these methods inspired the design of a sequential hybrid system by which higher treatment efficiency and less energy consumption were acquired compared to a conventional system. The hybrid system consisted of an electro-Fenton and an nZVI slurry system working in sequence. Both sub-systems were first optimized using the Response Surface Methodology (RSM), and the hybrid system was then designed accordingly. 94.06% of COD removal was achieved by the hybrid system in only 47.5 min at its optimum condition (CODinitial = 500 mg/L, [nZVI] = 0.9 g/L, and H2O2/Fe2+ = 3.6). Whereas it took more than 75 min for the single electro-Fenton system to acquire similar efficiency. GC–MS analysis also supported the superiority of the hybrid system over the conventional one.

Modeling of Tubular Electrochemical Reactor with a Spiral Design of Anode for Treatment of Petroleum Refinery Wastewater

Petroleum effluent is often made up of a complex combination of metals and organic molecules. In the present work, modeling of a tubular electrochemical reactor (TER) with a novel design operated at batch recycle for petroleum refinery effluent treatment by anodic oxidation was investigated. The reactor is composed from a cylindrical stainless steel cathode and a spiral porous graphite anode at its center. The impact of flow rate on the COD reduction and mass transfer coefficient (k) was studied. Results showed that increasing flow rate led to higher removal efficiency of COD and higher mass transfer coefficient where COD removal of 70% and k with value of 6.283x10-4 cm/s were obtained at flow rate of 4l/min. A power low correlation was obtained between mass transfer coefficient(k) and Reynolds number (Re) with coefficient of determination (R2) equal to 0.994869.This relation can be described as k=1.906x10-6(Re) 0.545 with range of Re 10000≤Re≤ 40000 prevailing turbulent conditions.

Optimization studies on bio-oil yield using microwave-assisted pyrolysis of bio-sludge

In this study, bio-sludge from a vegetable oil refinery effluent treatment plant was taken. The Proximate, ultimate, and elemental analyses of bio-sludge were done. Microwave-assisted fast pyrolysis using Box-Behnken design response surface methodology was applied to investigate the optimum conditions to produce high bio-oil from bio-sludge using activated carbon as microwave absorbent. The bio-oil obtained at the optimal condition was characterized using Fourier Transform infrared (FT-IR) spectroscopy and gas chromatography-mass spectrometry (GC/MS). It was found that the optimum bio-oil yield of 37.40% was estimated at the microwave power of 560 W, the particle size of 4 mm, and the microwave absorbent quantity of 1 g. The gross calorific value of 18.6 MJ/kg and a viscosity of 3.2 mPa S at 40 °C were obtained for bio-oil.

Hydraulic characterization and removal of metals and nutrients in an aerated horizontal subsurface flow “racetrack” wetland treating primary-treated oil industry effluent

Constructed wetlands (CW) are an attractive technology due to their operational simplicity and low life-cycle cost. It has been applied for refinery effluent treatment but mostly single-stage designs (e.g., vertical or horizontal flow) have been tested. However, to achieve a good treatment efficiency for industrial effluents, different treatment conditions (both aerobic and anaerobic) are needed. This means that hybrid CW systems are typically required with a respectively increased area demand. In addition, a strong aerobic environment that facilitates the formation of iron, manganese, zinc and aluminum precipitates cannot be established with passive wetland systems, while the role of these oxyhydroxide compounds in the further co-precipitation and removal of heavy metals such as copper, nickel, lead, and chromium that can simplify the overall treatment of industrial wastewaters is poorly understood in CW. Therefore, this study tests for the first time an innovative CW design that combines an artificially aerated section with a non-aerated section in a single unit applied for oil refinery wastewater treatment. Four pilot units were tested with different design (i.e., planted/unplanted, aerated/non-aerated) and operational (two different hydraulic loading rates) characteristics to estimate the role of plants and artificial aeration and to identify the optimum design configuration. The pilot units received a primary refinery effluent, i.e., after passing through a dissolved air flotation unit. The first-order removal of heavy metals under aerobic conditions is evaluated, along with the removal of phenols and nutrients. High removal rates for Fe (96–98%), Mn (38–81%), Al (49–73%), and Zn (99–100%) generally as oxyhydroxide precipitates were found, while removal of Cu (61–80%), Ni (70–85%), Pb (96–99%) and Cr (60–92%) under aerobic conditions was also observed, likely through co-precipitation. Complete phenols and ammonia nitrogen removal was also found. The first-order rate coefficient (k) calculated from the collected data demonstrates that the tested CW represents an advanced wetland design reaching higher removal rates at a smaller area demand than the common CW systems.

Conventional and high resolution chemical characterization to assess refinery effluent treatment performance

Refinery effluents represent an emission source of hydrocarbons (HCs) and other constituents to the environment. Thus, characterisation of effluent quality in terms of concentrations of key parameters relative to permitted standards is important and for total petroleum hydrocarbons (TPH), the specific composition of the HC mixture can affect its toxicity to aquatic organisms. Therefore, this study was designed to analyse TPH, benzene, toluene, ethyl benzene, xylenes (BTEX), polycyclic aromatic hydrocarbons (PAHs), (bio) chemical oxygen demand, total nitrogen, total suspended solids and selected metals before, and after, treatment steps to demonstrate removal efficiencies across 13 refineries with variable wastewater treatment systems. Final discharge concentrations of the measured parameters were by 97% within the so called Best Available Technique Associated Emission Levels (BAT-AELs). Further, TPH composition was characterised using high-resolution two-dimensional gas chromatography (GCxGC) analysis to understand the mass distribution by carbon number and specific chemical class. Measurements were compared to SimpleTreat model predictions for validation. SimpleTreat successfully predicted the shape of the effluent composition since it is essentially a removal constant applied to the influent composition. The predictions were of similar magnitude as, or were greater than, the effluent concentrations since SimpleTreat is based on typical performance and is intended to be conservative. This was especially true for aromatic constituents. Reduction in potential HC exposures also coincided with a decrease in predicted toxicity using a mechanistic oil toxicity model, PETROTOX. Overall, the results indicate that EU petroleum refineries are likely to achieve a high performance level regarding effluent treatment.

Optimization of Crude Oil Biodegradation of Fungi Isolated from Refinery Effluent Site using Response Surface Methodology

The activities involved in the production and exploration of crude oil has constantly polluted the environment. This study investigated the ability of an indigenous fungus to utilize petroleum hydrocarbon. Response Surface Methodology was used to optimize the effects of pH, microbial concentration (spores/ml), and contact time (days) on the crude oil removal efficiency in refinery effluent. Monocillium sp. was isolated and used for the treatment of refinery effluent due to its predominance in the contaminated soil. Twenty experimental runs were analyzed to determine the effect of pH, microbial concentration and contact time on the oil removal efficiency. From theexperimental results obtained, a maximum oil removal efficiency of 98.42 % was achieved at a pH of 6.5, contact time of 14 days, and a microbial concentration of 3 spores/ml. The results obtained showed the percentage of crude oil removal in the effluent sample increased with an increase in time. Optimization of the experimental result was achieved at a removal efficiency of 98.59 %, a contact time of 13.96 days, a pH of 6.85, and a microbial concentration of 3.01 spores/ml. The findings of this study revealed that Monocillium sp. is a viable hydrocarbon degrader, and can be used in the bioremediation of petroleum contaminated environments.
 Keywords: Response surface, optimization, bioremediation, hydrocarbon, removal efficiency, Monocillium sp.

Removal of Petroleum Contaminants Through Bioremediation with Integrated Concepts of Resource Recovery: A Review.

There is an upsurge in industrial production to meet the rising demands of the rapidly growing population globally. The enormous energy demand of the growing economies still depends upon petroleum. It has also resulted in environmental pollution due to the release of petroleum origin pollutants. Soil and aquifers, especially in the direct impact zones of petroleum refineries, are the worst hit. The integrated concept of bioremediation and resource recovery offers a sustainable solution to mitigate environmental pollution. It involves biodegradation, a benign utilization of toxic wastes, and the recycling of natural resources. Bioremediation is considered an integral contributor to the emerging concepts of bio-economy and sustainable development goals. This review article aims to provide an updated overview of bioremediation involving petroleum-based contaminants. Microbial degradation is discussed as a promising strategy for petroleum refinery effluent and sludge treatment. The review also provides an insight into resource reuse and recovery as a holistic approach towards sustainable refinery waste treatment. Furthermore, the integrated technologies that deserve in-depth exploration for future study in the refinery sector are highlighted in the present study.

Extraction of Bio Polymers from Crustacean Shells and its Application in Refinery Wastewater Treatment

The fisheries sector is one of the most ancient and important sectors in the world and plays a significant role in providing the nutrition and socio-economic development of the country. The fish processing industry produces huge quantities of wastewater, encompassing significant amounts of contaminants in the form of soluble, colloidal, and particulate matters. The disposal of shellfish waste is a serious issue, and the effluents discharged from seafood-processing plants contain high amounts of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), dissolved solids, suspended solids, and turbidity. The existing waste management system lacks a cost-effective and environmentally friendly method. The current research focus on the extraction of a biopolymer chitosan from crab shells by ecofriendly methods and its application in refinery wastewater treatment. The chemical structure and crystallinity of the extracted chitosan was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) analyses. Surface morphology and elemental composition were determined using Scanning Electron Microscopy (SEM), and Energy-Dispersive X-Ray Analysis (EDX). Thermal properties were detected using Thermo Gravimetric Analysis (TGA). The extracted chitosan was successfully employed in the batch treatment of refinery effluent by varying the experimental parameters (refinery effluent solution pH, contact time, dosage of chitosan, and stirring speed) and the optimizations of the processing conditions were established.

Treatment of petroleum refinery effluents and wastewater in Iraq: A mini review

In the analysis undertaken, we review waste from the crude oil and fuel refining. In addition to petrochemical intermediate products industry in Iraq in petroleum refinery effluents (PRE). The study shows the significant detrimental impacts of the Iraqi refinery effluent pollution. The research illustrated the handling of wastewater in refineries. This study shows that the emissions from Iraqi refineries comes out to the farthest extent. We were often based on environmental toxins such as Couscous Pollutants, Liquid Pollutants and Strong Pollutants in the Southern Refineries. In addition, we follow the forms in which refining waste in Iraq is treated. To date, oil refineries have struggled to meet their commitments effectively while atmospheric regulation in their fields continues to be neglected and environmental protection schemes that contribute to oil pollution mitigations are less regarded. The government, on the other hand, has shown no commitment to enact its minimum environmental legislation. As a consequence, it is clear that the area’s oil and refineries, particularly refineries, have important repercussions for livelihoods and agriculture.

Treatment of a natural gas refinery effluents by electrocoagulation

The effluent of a petroleum refinery which presently is being inefficiently and poorly treated was treated by electrocoagulation in order to eliminate organics and suspended matter. A rectangular plate of specially made aluminum was used as anode placed parallel and 5 cm apart from a stainless-steel cathode. A source of power supply equipped with a preselected working range of 0-30 V and controllable amperage of up to 5 amperes was used to provide the required current density. The liberated oxygen and hydrogen from electrodes carried the emulsified effluent oil and accumulated on the top as a film. It was noticed that 94% of suspended matter could be removed by electrocoagulation under optimum conditions of pH = 6, current density of 35 mA/cm2 after 120 minutes of treatment. It was also noticed that at least 90% of chemical oxygen demand would be removed if the above-mentioned conditions were maintaining. Further results showed that the removal efficiency would decline either by increase or decrease of current density. Aluminum hydroxide precipitates which form in basic solutions are the main contributor of suspended matter removal in this region. They enhance enmeshment of particulates while settling. It was interesting to note that no dissolved organics were found in the aqueous phase of the original effluent except for low molecular weight hydrocarbons C7-C22 and their concentration was in the range of 0.8 to 25 ppm, which is below their solubility in water. All organics in the effluent were in the form of liquid or solid suspended matter primarily as higher molecular weight hydrocarbons. In a separate experiment the wastewater was treated by chemical coagulation. It was noticed that under most favorable conditions 75% of turbidity was removed when poly aluminum chloride was used as coagulant. Aluminum sulfate and lime were also used as coagulants but no favorable results were obtained. Combined application of electrocoagulation and chemical coagulation improved turbidity removal not more than 4%.

Bacterial cellulose as an oleaginous yeast cell carrier for soybean oil refinery effluent treatment and pyrolysis oil production.

Bacterial cellulose produced from soybean oil refinery effluent is a good immobilization carrier because of the large pores in its fiber network, its high water-holding capacity, and its good biocompatibility. In this study, it was applied to immobilization of oleaginous yeasts for treating soybean oil refinery effluent. The immobilization percentage reached 50%, and the removal of chemical oxygen demand and oil content reached 92.1% and 93.1%, respectively, during dynamic immobilization using a mass percentage of bacterial cellulose of 30% and an immobilization time of 24h, which were significantly higher than those of free oleaginous yeasts or yeasts immobilized by bacterial cellulose from rich medium. The immobilized oleaginous yeasts facilitated the recovery of the yeasts and effectively treated three batches of soybean oil refinery effluent. The immobilized oleaginous yeasts recovered after soybean oil refinery effluent treatment were pyrolyzed to produce bio-oil, which contributed to more alkanes and a higher calorific value of bio-oil in the pyrolysis products as compared to those of free oleaginous yeasts. As bacterial cellulose used as an oleaginous yeast cell carrier is produced from soybean oil refinery effluent, no waste of immobilization materials is involved and an efficient waste-into-oil bioprocess is developed.

Treatment of Palm Oil Refinery Effluent Using Tannin as a Polymeric Coagulant: Isotherm, Kinetics, and Thermodynamics Analyses.

The refining of the crude palm oil (CPO) generates the palm oil refinery effluent (PORE). The presence of high contents of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, and suspended solids (SS) in PORE encourages the determination of an effective treatment process to minimize the environmental pollution and preserve aquatic life. In the present study, a biodegradable natural polymer, namely tannin, was utilized as a coagulant to treat PORE. The coagulation experiment was conducted using a jar test apparatus. The tannin coagulation efficiency was evaluated based on the BOD, COD, turbidity, and SS removal from PORE by varying the tannin dose (50–300 mg/L), pH (pH 4–10), treatment time (15–90 min), and sedimentation time (15–90 min). It was found that the maximum removal of BOD, COD, turbidity, and SS was 97.62%, 88.89%, 93.01%, and 90.21%, respectively, at pH 6, a tannin dose of 200 mg/L, 60 min of coagulation time, and 60 min of sedimentation time. Analyses of isotherm models revealed that the Freundlich isotherm model was well fitted with the coagulation study. Kinetics studies show that the pseudo-second-order kinetics model was the well-fitted kinetics model for the BOD, COD, turbidity, and SS removal from PORE using tannin as a polymeric coagulant. The determination of thermodynamics parameters analyses revealed that BOD, COD, turbidity, and SS removal from PORE was spontaneous, exothermic, and chemical in nature. The finding of the present study shows that tannin as a natural polymeric coagulant would be utilized in PORE treatment to avoid toxic sludge generation.

Simulating behavior of petroleum compounds during refinery effluent treatment using the SimpleTreat model

Distribution and elimination of petroleum products can be predicted in aerobic wastewater treatment plants (WWTPs) using models such as multimedia fate model SimpleTreat. An advantage of the SimpleTreat model is that it only requires a few basic properties of a chemical in wastewater to calculate partitioning, biodegradation and ultimately emissions to air, surface water and produced sludge. The SimpleTreat model structure reflects a WWTP scheme. However, refinery WWTPs typically incorporate more advanced treatment processes such as dissolved air flotation (DAF), a process that clarifies wastewaters by the removal of suspended matter such as oil or solids. The objective of this work was to develop a WWTP removal model that includes DAF treatment. To understand how including a DAF in the model affects the predicted concentrations of petroleum constituents in effluent, we replaced the primary sedimentation module in SimpleTreat with a module simulating DAF. Subsequently, we compared results from the WWTP-DAF model with results obtained with the original SimpleTreat model for a library of over 1500 representative hydrocarbon constituents. The increased air-water exchange in a WWTP-DAF unit resulted in higher predicted removal of volatile constituents. Predicted removal with DAF was on average 17% larger than removal with primary sedimentation. We compared modelled results with measured removal data from the literature, which supported that this model refinement continues to improve the technical basis of assessment of petroleum products.

Kinetic and parametric studies of refinery effluent treatment in electrochemical reactor

Treatment of refinery effluent using an electrocoagulation reactor assisted with a natural coagulant, from Acacia tortilis, was investigated under controlled operating conditions. The influence of process variables – namely, type of electrode (copper (Cu), steel and aluminium (Al)), effluent pH (3·5–11·5), influent chemical oxygen (O2) demand (COD) of the effluent (605–2420 mg/l), coagulant dosage (1·0–6·0 g/l), voltage (15–45 V) and current (1·5–2·5 A) – on the COD removal efficiency was investigated. Among the different electrodes tested, the aluminium electrode performed well and could remove 74·2% at an equilibrium time of 90 min. Formation of the aluminium hydroxide (Al(OH)3) complex was identified as the working mechanism. The optimal conditions for better COD removal efficiency were identified as pH 5·5, coagulant dose of 4·0 g/l, voltage of 45 V and current of 2·5 A. The empirical relationship between the coagulant dose and the COD removal percentage was found to be exponential in nature. A pseudo-second-order kinetic model was found to represent the experimental data very well (coefficient of determination > 0·900) and the kinetic constant (k2) was estimated as 0·20 × 10−3(g/mg)/min at an initial effluent COD of 2420 mg/l.

Treatment of oil refinery effluent using bio-adsorbent developed from activated palm kernel shell and zeolite.

This study investigated the potential of palm kernel shell (PKS) as a biomass feed for adsorbent production. This work aims at synthesizing green adsorbent from activated PKS by integrating iron oxide and zeolite. The newly developed adsorbents, zeolite-Fe/AC and Fe/AC, were analyzed for surface area, chemical composition, magnetic properties, crystallinity, and stability. The adsorbent efficiency in removing effluent from the palm oil mill was evaluated. The influence of operating parameters, including adsorbent dosage, H2O2, reaction time, and initial solution pH for adsorption performance was studied. The Fourier transform infrared analysis revealed that the adsorbents contain functional groups including OH, N–H, C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> O and CC, which are essential for removing pollutants. The SEM-EDX analysis shows holes in the adsorbent surface and that it is smooth. The adsorption study revealed that under optimized conditions, by using 4 g L−1 of adsorbent and 67.7 mM H2O2, zeolite-Fe/AC was able to remove 83.1% colour and 67.2% COD within 30 min. However, Fe/AC requires 5 g L−1 of adsorbent and 87.7 mM to remove 86.8 percent and 65.6 percent, respectively. This study also showed that zeolite-Fe/AC has higher reusability compared to Fe/AC. Among Freundlich and Temkin models, the experimental data were found to be best fitted with the Langmuir isotherm model. The kinetic analysis revealed that for both adsorbents, the adsorption process fitted the pseudo-second-order model (R2 = 0.9724). The finding reflects monolayer adsorption of zeolite-Fe/AC and Fe/AC. This study thus demonstrates the applicability of low-cost green adsorbents produced from PKS to treat oil refinery effluent and other recalcitrant wastewaters.

Treatment of Port Harcourt Refinery Effluent by a Bacterial Consortium Immobilized on Agro-based Bio Carriers

Discharge of poorly treated refinery wastewater has always been a major environmental challenge. Bacterial immobilization is key to the maintenance of biomass on a contaminated site. In this study, a mixed culture of three bacterial isolates from oil-polluted water: Pseudomonas aeruginosa (MN294989), Bacillus tequilensis (MN294990) and Micrococcus sp. immobilized on Groundnut Shell (GS), Melon Husk (MH) and Sugarcane Bagasse (SB) were employed in the bioremediation of Port Harcourt refinery wastewater. Surface area and pore size distribution of the agro-based bio carriers were suitable for bacteria adhesion. The bacterial isolates were screened for phenol, naphthalene and hydrocarbon utilization. Scanning Electron Microscopy (SEM) was used to ascertain the immobilization of the consortium on the agro-base carriers. A 15-days laboratory-scale treatment of refinery raw wastewater was compared in the immobilised and immobilized consortium. The agro-based residue immobilized consortium enhanced the reduction in BOD5, COD, oil and grease, phenol by 7%, 9%, 30% and 5% respectively compared to the free form of the consortium. This study underscores the role of immobilization in maintaining high bacterial biomass on contaminated site and possible improvement in bioremediation of refinery wastewater.