Activated Carbon Filtration Research Articles

Effect of Charcoal and Active Carbon as Filter Media on Electrokinetic Remediated Crude Oil Contaminated Soil

Research has shown that traditional electrokinetic remediation (EKR) technology has limited efficiency against different contaminants and soils. This has led to the use of several strategies to enhance the traditional EKR for higher contaminants removal efficiency. This paper separately uses charcoal and active carbon each 1 cm thick as filter media in EKR to enhance the removal of crude oil from crude oil contaminated soil (COCS) containing 78,600 mg/kg of crude oil. The filters are placed very close to the anode compartment containing 0.01 M NaOH electrolytes. Graphite electrodes are used in a face to face configuration to pass 1 V DC/cm through the COCS. Crude oil removal efficiencies of 81.4% and 84.6% respectively are obtained from the EKR setups containing charcoal and active carbon filters after 18 days and 14 days of remediation respectively. This makes active carbon a better filter medium than charcoal for COCS. The results of the chemical oxides compositions show improvement from non-lateritic COCS to lateritic for the filter media enhanced EKR soil. Although active carbon has proven to be a better filter medium compared to charcoal for use in enhancing EKR technology for COCS. Nonetheless, with over 80% removal efficiency, charcoal or active carbon filters be used to enhance EKR remediation of COCS.

Investigation of the Effect of Airborne Contaminants on PEM Fuel Cell Stack Performance and Degradation Using Electrochemical Impedance Spectroscopy, AVL Thda™ and FTIR Gas Analyzer

Air pollution is still a bitter truth in many locations in the world. In highly populated regions like metropolitan areas as well as in agricultural areas there are various airborne contaminants which can be harmful to organisms. Also fuel cells, especially PEMFC are sensitive to airborne contaminants.In most mobile and stationary PEM fuel cell systems, ambient air is used as oxidant gas at the cathode of the fuel cell. It is cost and weight saving because there is no need to install additional tank for pure oxygen and to refill it, but the performance of fuel cell can suffer beyond the oxygen gain from airborne contaminants, which also have the potential to accelerate degradation. To prevent that airborne contaminants reach the fuel cell cathode, air filter systems consisting of particle filter and additional activated carbon filter are installed at the cathode inlet.The focus here is on the investigation of the use of AVL THDAtm method to detect effects of airborne contaminants. THDA (total harmonic distortion analysis) is a patented online fuel cell monitoring method based on analyzing harmonic distortion effects of voltage drifts instead of single cell voltage measurement. So far it was successfully demonstrated for the detection of water issues like flooding and drying, and for low media supply issues on both cathode and anode side [1, 2].For the development and validation of the method, experiments with a PEMFC stack are going to be done on a fuel cell testbed equipped with an AVL X-Ion impedance analyzer. Specific air pollutant gases ammonia (NH3), sulfur dioxide (SO2) and nitrogen oxides (NOx) are going to be mixed into the cathode air in the ppb range. Their effects on PEMFC stack performance are going to be investigated with electrochemical impedance spectroscopy (EIS) and total harmonic distortion analysis. The cathode exhaust gas is also going to be analyzed by an FTIR gas analyzer.It is planned to test the PEMFC stack under different operating conditions, with various parameters and different cathode gas mix ratios while monitoring possible conversion of impurities via FTIR and the stack state of health using THDA and conventional technologies to understand the link between the effect of airborne contaminants on fuel cell stack performance, on its lifetime and to determine possible early indicators in the THDA signals.

Emerging and legacy per- and polyfluoroalkyl substances (PFAS) in fluorochemical wastewater along full-scale treatment processes: Source, fate, and ecological risk

The increasing applications of emerging per- and polyfluoroalkyl substances (PFAS) have raised global concern. However, the release of emerging PFAS from the fluorochemical industry remains unclear. Herein, the occurrence of 48 emerging and legacy PFAS in wastewater from 10 fluorochemical manufacturers and mass flows of PFAS in a centralized wastewater treatment plant were investigated. Their distribution and ecological risk in neighboring riverine water were also evaluated. In wastewater from fluorochemical manufacturers, PFAS concentrations were in the range of 14,700–5200,000 ng/L and 2 H,2 H-perfluorooctanoic acid (6:2 FTCA), perfluorooctanoic acid (PFOA), N-ethyl perfluorooctane sulfonamide (N-EtFOSA), and 1 H,1 H,2 H,2 H-perfluorodecanesulfonate (8:2 FTS) were the major PFAS detected. Several PFAS displayed increased mass flows after wastewater treatment, especially PFOA and 6:2 FTCA. The mass flows of PFAS increased from − 20% to 233% after the activated sludge system but decreased by only 0–13% after the activated carbon filtration. In riverine water, PFAS concentrations were in the range of 5900–39,100 ng/L and 6:2 FTCA, 1 H,1 H,2 H,2 H-perfluorodecyl phosphate monoester (8:2 monoPAP), 1 H,1 H,2 H,2 H-perfluorooctyl phosphate monoester (6:2 monoPAP), PFOA, and perfluorohexanoic acid (PFHxA) were the major PFAS detected. PFOA and 6:2 FTCA exhibited comparable hazard quotients for ecological risk. Current wastewater treatment processes cannot fully remove various PFAS discharged by fluorochemical manufacturers, and further investigations on their risk are needed for better chemical management.

Adsorption and desorption processes of trihalomethanes on different granulated activated carbons in a full-scale advanced water treatment plant

Abstract Trihalomethanes (THMs) are one of the main disinfection by-products generated in drinking water (DW). To control health risks caused by THMs several countries have established a maximum content of these chemicals in DW. THMs can be removed by granular activated carbon (GAC) and their adsorption processes have been studied by different authors. However, there are few studies on their desorption from GAC and no data are available on their desorption at a full scale. This paper summarises the results obtained in the monitoring of the adsorption and desorption processes of THMs at a full-scale DW plant considering different types and stages of GACs, as well as several types of influent waters. This research was carried out during 3 years in a full-scale advanced DW plant (6.25 m3·h−1) that can use four different pre-oxidants. An increase on THMs concentration in the outlet of the AC filters due to desorption processes were checked, although the obtained doses were always far below the established European limit (100 μg/L).

Fabrication of coconut shell activated carbon filter system for removal of colour and pollutants in textile dye effluent

The present study evaluates the Decolorization and pollutant removal efficiency of chemically impregnated coconut shell-activated carbon using textile dye effluent in the filtration system. The coconut shell zinc chloride activated carbon (CSZAC) was used as a filtering media in wastewater treatment due to its wider pore space with better surface area (590.80 m2 g−1) and higher adsorption capacity. The SEM micrograph revealed that the activated carbon had networks of parallel running pores with internal microstructure and more active sites. The designed activated carbon filter system has dimensions of 90 x 60 x 30 cm; the sections included are the holding tank (50 liters capacity), filtration tank and storage tank with the optimized flow rate of 5 x 10−4 m3 min−1. The Color, pH, EC, TDS, TSS, BOD and COD of textile dyeing wastewater were significantly reduced, after the treatment through the CSZAC filtration system. The initial color concentration of textile dye effluent was 7021 HU and after treatment, the color was fully reduced and became colorless. CSZAC treatment reduced the BOD from 600 mg L−1 to 89.7 mg L−1 (80.6 per cent) and COD from 2500 mg L−1 to 205 mg L−1 (90.5 per cent). Therefore, CSZAC can be used as an effective adsorbent material to remove different dye compounds and pollutants from textile wastewater.

Optimizing backwash control using data on seasonal changes in the invertebrate community of granular activated carbon filters

Problems associated with the colonization and leakage of invertebrates in the granular activated carbon (GAC) filters of waterworks have received increased attention in recent years. To study the effect of environmental factors and water quality on invertebrate abundances, and the backwash control for minimizing invertebrate abundance. A survey of the invertebrate community of GAC filters was carried out monthly from March 2021 to May 2022. A pilot-scale GAC system established in the laboratory alongside a lake, with a volume of 35.3 L. 45 invertebrate species were detected, and 40 of these were rotifers. Significant variation in abundance was observed among seasons before and after GAC filtration, the average invertebrate abundance in the inlet water was 11.1 times that in the filtrate. The GAC filter contained invertebrates that might be responsible for the large number of organisms in the filtrate. Invertebrate abundance in the GAC filter decreased gradually with the carbon layer depth, which the mean invertebrate abundances were 6,926, 5,232, and 3818 ind./kg in the top layer (TL), middle layer (ML), and bottom layer (BL), respectively. Invertebrate abundance was correlated with water temperature and varied seasonally. Among eight water quality parameters, chlorophyll a (Chla) and the total plate count (TPC) were most significantly correlated with invertebrate abundance. According to the statistical modeling and the optimization process of response surface methodology (RSM). The predicted optimal values were a flow rate of 6.36 L/h, a backwash cycle of 3.26 d, and a backwash intensity of 14.97 L/(m2·s) for a minimum invertebrate abundance of 3013 ind./kg in the GAC filter. To maintain invertebrate abundance within an acceptable range, some of these measures might need to be modified depending on the actual conditions.

Microbial community of the initial stage of biologically active carbon filters’ work and its role in organic matter removal from water

Microbial community of the initial stage of biologically active carbon filters’ work and its role in organic matter removal from water

Efficiency of home water filters on pesticide removal from drinking water

Water pollution via natural and anthropogenic activities has become a global problem, which can lead to short and long-term impacts on humans' health and the ecosystems. Substantial amounts of individual or mixtures of organic pollutants move into the surface water via point and non-point source contamination. Some of these compounds are known to be toxic and difficult to remove from water sources, thus affecting their quality. Moreover, environmental regulations in high-income countries have become very strict for drinking water treatment over the past decades, especially regarding pesticides. This study aimed to evaluate the efficiency of different residential water treatments to remove 13 pesticides with distinct physicochemical characteristics from the drinking water. Nine water treatments were used: four membrane filters, an activated carbon filter, ultraviolet radiation, reverse osmosis, ion exchange resins, and ozonation. The trial was performed with tap water contaminated with an environmental concentration of 13 pesticides. According to the results, activated carbon and reverse osmosis were 100% efficient for pesticide removal, followed by ion exchange resins and ultraviolet radiation. Membrane filters, in general, showed low efficiency and should, therefore, not be used for this purpose.

In situ growth of MIL-101 (Fe) on waste PET plastic slices for effective arsenic removal

Converting waste Polyethylene terephthalate (PET) plastic into value-added metal–organic frameworks (MOFs) has emerged as a prospective solution to plastic upcycling. Within this work, MIL-101(Fe)@PET was fabricated via microwave method. The as-prepared MIL-101(Fe)@PET performed high removal efficiency (100 %) toward three arsenic pollutants at low concentration (1 mg/L) within 60 min. The maximum adsorption capacity of MIL-101(Fe)@PET toward 4-aminophenylarsonic acid (ASA), hydroxy-3-nitrobenzenearsonic acid (ROX) and As(V) were 320.6, 476.5, 240.0 mg g−1, respectively. Further, the household water purifiers filter was assembled adopting the as-prepared MIL-101(Fe)@PET as absorbent. MIL-101(Fe)@PET filter performed higher arsenic removal efficiency than active carbon filter and commercial filter. The adsorption behaviors of MIL-101(Fe)@PET toward arsenic was found to be fitted with pseudo-second-order kinetic models and Langmuir isotherm models. The possible adsorption mechanism was proposed. The developed strategy provides a new method in the application of MOFs-based materials and upcycling waste plastics.

Detailed organic characterization of process water to evaluate reverse osmosis membrane fouling in industrial wastewater treatment

One of the major waste streams within the oil and gas (O&G) industry is produced and process water generated during hydrocarbon production and treatment, respectively. In gas production facilities, process water typically has lower salinity (i.e., <10,000 mg/L) which present opportunities for these wastewaters to be treated for beneficial reuse applications via advanced water treatment technologies, such as reverse osmosis (RO) membranes. One of the key challenges for RO membranes application to industrial wastewater treatment is fouling which is frequently attributed to the soluble organics present in the water and/or associated with field chemicals. In this study, a detailed organic characterization methodology, using liquid chromatography with organic carbon detector (LC-OCD) was applied to characterize the organics on a real process water collected from industrial wastewater treatment plant at a gas production facility. Additionally, a rigorous bench-scale testing procedure was implemented to assess the performance of a full-scale RO system with and without activated carbon filter (ACF) pretreatment, making this study the first one to apply LC-OCD methodology on real wastewater to evaluate the fouling of RO membranes deployed at an industrial treatment plant. Bench-scale RO results showed that in the absence of ACF pretreatment, a 12 % decline in membrane permeability (from 1.78 to 1.57 L/(m2-bar-h)) was observed, while no permeability decline was measured after ACF treatment. The organic fouling was confirmed by mass balance calculations on the bench scale experiments as well as Fourier Transform Infrared (FTIR) analysis on the membrane coupons. Moreover, LC-OCD analysis showed that the ACF inlet has a TOC concentration of approximately 3.06 mg/L; of those 1.29 mg/L (42 %) are hydrophobic, and 1.77 mg/L (58 %) are hydrophilic. After ACF treatment, the hydrophobic organics decreased to 0.65 mg/L, revealing that the ACF is removing >50 % of hydrophobic organics which are likely responsible for membrane fouling. Bench-scale operational and water quality results were comparable to the full-scale RO performance data validating the lab testing procedure implemented in this study.

Microplastics attenuation from surface water to drinking water: Impact of treatment and managed aquifer recharge – and identification uncertainties

River water can be used to recharge aquifers exploited for drinking water production. Several recent studies reported microplastics (MPs) in river water, and therefore, the potential contamination of groundwater by MPs is a growing concern among stakeholders and citizens. In this research, we investigate the fate of MPs (> 20 μm) along six different stages of a major Managed Aquifer Recharge (MAR)-water supply system in Switzerland. About 20 l of water were filtered using steel meshes at each location in triplicates. In the laboratory, MPs deposited on the anodisc filters were identified using Focal Plane Array (FPA) micro-Fourier-Transform-InfraRed (μFTIR) spectroscopy. The obtained hyperspectral data were processed using the imaging software Microplastics Finder for MPs identification and classification. Our results revealed a 20-fold decrease in MPs concentration from the Rhine River bed water (112 ± 27.4 MPs/l) to after the coagulation, flocculation and sedimentation (5.5 ± 2.2 MPs/l), a further 3-fold decrease to after the sand-filtration system (1.8 ± 0.9 MPs/l), corresponding to an overall removal efficiency of 98.4 %. The MPs concentrations remained low following MAR (2.7 ± 0.7 MPs/l) through a Quaternary gravel aquifer. Activated carbon filters did not substantially further reduce MPs concentrations. The percentage of fragments (≈95 %) prevailed over fibers (≈5 %) at all locations, with fibers being longer and more abundant in the river water. Overall, this study demonstrates the effectiveness of the treatment systems to remove MPs larger than 20 μm. Finally, we calculated an uncertainty in MPs concentrations of one order of magnitude depending on the user-defined parameters inside the MPs identification and classification model. The Quality Assurance/Quality Control approach followed during laboratory analysis highlighted an accumulation of surrogate particles at the edges of the disc, which would have an impact for MPs number upscaling.

An efficient integrative method for a sustainable environmental management of produced water: Application on the Zelten oil field, sirte basin, Libya

Oil produced water (OPW) has a complex composition with different, toxic organic and inorganic pollutants. These compounds are generally insoluble and disperse in water as an emulsion. Disposal without treatment causes adverse environmental effects. Therefore, the aim of this study is to develop a simple and dedicated remedial process specifically adapted to the oil field in Libya and to determine how to benefit from this treated water. At this level, samples were collected in both the outer separators and the disposal pit of the Zelten oilfield, Libya. Water samples were analyzed to determine their hydrocarbons (HC) contents, heavy metals, chemical oxygen demand, turbidity, salinity, and total dissolved solids, before and after treatment by sand filter, sand-dolomite filter, activated carbon-sand filter, sand-activated carbon-dolomite filter, and extraction by solvent. HC processing efficiency was evaluated by using gas chromatography–mass spectrometry. Using a descriptive and analytical design, this study achieved 50, 81, 87, 91, and 97.97 % respective efficiencies; sand activated carbon filters, slurry filter column, and the solvent showed higher hydrocarbon removal efficiency (81 and 97 %). Treated OPW can be reused for many applications, including irrigation and re-injection into depleted wells.

Biological Activated Carbon Filtration Controls Membrane Fouling and Reduces By-Products from Chemically Enhanced Backwashing during Ultrafiltration Treatment

Water purification by ultrafiltration (UF) requires regular membrane cleaning via backwashing. In the case of chemically enhanced backwashing (CEB), it can result in the formation of unwanted by-product precursors due to reactions with organic matters present in the backwashing water and accumulating on the membrane. After subsequent disinfection, these precursors are prone to generate trihalomethanes (THMs) and haloacetic acids (HAAs), posing potential risks to the chemical safety of drinking water. However, limited information was available regarding the removal of these disinfection by-products. In this study, biological activated carbon (BAC) pretreatment followed by UF with chemically enhanced backwashing (CEB) (BAC-UF-CEB) was investigated to mitigate membrane fouling and reduce by-product formation. It was tested in parallel with UF with CEB (UF-CEB) and UF with sole physical backwashing. Compared to UF-CEB, BAC pretreatment prior to UF-CEB reduced transmembrane pressure (TMP) by 49.0%. BAC achieved high removals of dissolved organic carbon (59.99%) and UV254 absorbance (80.82%) in the BAC-UF-CEB effluent. Moreover, BAC-UF-CEB substantially decreased trihalomethane and haloacetic acid formation potentials by 83.28% compared to UF-CEB. BAC alleviated irreversible membrane fouling by 78.7%. By removing disinfection by-product precursors, BAC-UF-CEB markedly improved treated water quality and chemical safety. This study demonstrates BAC pretreatment effectively mitigates membrane fouling and controls disinfection by-products during UF water treatment.

Long-term performance and biofilms of the novel nano manganese dioxide coupling carbon source pre-loaded biological activated carbon filters for drinking water

In order to accelerate the start-up of biological activated carbon (BAC) filters and enhance ammonium (NH4+-N) removal performance, three substrates (sucrose and/or nano manganese dioxide (nMnO2)) pre-loaded BAC filters were set up to investigate the pollutants removals and microbiological characteristics for a long-term operation of 197 days. The average NH4+-N removal performance treated by the sucrose coupled with nMnO2 loaded BAC filter was the highest (71.18 %), which was 3.83 times of that by the control filter (18.58 %). 29 % of NH4+-N treated by the sucrose coupled with nMnO2 loaded BAC removed through the traditional nitrification and denitrification, or simultaneous nitrification and denitrification (SND) pathways according to the calculation of the alkalinity consumption (6.12 mmol/L). There was no leakage of carbon source and Mn, and no accumulation of nitrite from the substrates loaded BAC. The dominant bacteria in the sucrose coupled with nMnO2 loaded BAC were Dechloromona (accounting for 8.02% of the total bacterial) and Acidaminobacter (accounting for 15.16% of total bacterial) on the Day 180, which had the capacity of nitrification or denitrification. NH4+-N and micropollutants removals treated by the combined process of peracetic acid (PAA) pre-oxidation and substrates loaded BAC were significant due to the generation of assimilable organic carbon (AOC) (5.98 ± 1.93 μg-C/mL) by PAA (100 μM)/Fe2+ pre-oxidation and the higher biomass ((4.57 ± 3.07) × 107 cells/g DW BAC) in the sucrose coupled with nMnO2 loaded BAC filter. Therefore, nMnO2 coupling carbon source pre-loading strategy could not only enhance initial colonization, but also promote pollutants removals for long-term operation.

Removal of binary and ternary synergistic mixtures of ozone and VOCs by activated carbon filter: Mathematical modelling

Evaluating the activated carbon filter's performance in removing gaseous pollutants is essential to determining the filter maintenance schedule for indoor environments. This paper describes the development of a mathematical model to predict an activated carbon filter's performance for removing mixtures of ozone and volatile organic compounds (toluene and limonene) at their low-level concentrations in typical indoor environments. Mass transfer equations were employed to estimate the filter's dynamic behaviour by including the reaction rates of ozone with carbon surfaces and the reactive volatile organic compound, as well as the adsorption isotherm for a single volatile organic compound or binary mixtures of volatile organic compounds. The reaction rate constant for the ozone-limonene reaction was calculated by fitting the model to the experiment results of their binary mixture at 9 ppm of limonene and 0.1 ppm of ozone. Additionally, the ozone-exposed filters at 0.1 ppm were used to perform adsorption tests to determine the parameters of the Dubinin-Radushkevich isotherm using experimental results at 9, 30, 50, 70, and 90 ppm of volatile organic compounds. The Dubinin-Radushkevich isotherm was extended using the volume exclusion theory to consider the effect of by-products on the removal modelling of the binary mixture of ozone and limonene and the ternary mixture of ozone, limonene, and toluene.The model was able to show the reduced accessibility of the surface of activated carbon for reaction with ozone because of the adsorption of volatile organic compounds and generated by-products (keto-limonene and carvone). The initial influence is of minor magnitude; however, as the surface load intensifies, its significance can progressively amplify over time. Pre-exposing the filter to ozone prior to conducting adsorption tests was able to capture the average change in the adsorption properties of the filter. These considerations in the modelling result in a remarkable predictive capability in determining the breakthrough behaviour of the filter in removing the binary or ternary mixture of ozone and volatile organic compounds at various concentrations. The insignificant effect of the homogeneous reaction between ozone and limonene for the investigated experimental setup was confirmed by comparing the predictions made by the proposed model with those made by another model that considers the homogeneous reaction. Finally, the sensitivity analysis revealed that the model is more sensitive to adsorption isotherm parameters compared to the reaction kinetic parameter between ozone and limonene.

Practical Analysis of Tap Water Dissolved Solids Efficient Reduction

Water is an essential component in the manufacturing of oral solid dosage forms in the pharmaceutical industry. The objective of the present study is to develop a compact and easy-to-maintain one-platform solution for generating high-purity water with near to zero Total Dissolved Solids (TDS) and low conductivity for pharmaceutical applications. To achieve this objective, different purification methods were explored and integrated into a single platform. The purification process involved the use of Electro-Deionization (EDI) in combination with double-pass Reverse Osmosis (RO), an activated carbon filter, water softeners, and micron filtration. The resource water was carefully selected based on specific criteria to ensure the quality of the final purified water. The developed one-platform solution successfully produced purified water with near to zero TDS and a conductivity level below 1 micro siemens/cm2. The integrated approach involving EDI and double-pass RO, along with supplementary filtration and treatment steps, proved to be highly effective in achieving the desired purity levels. The study demonstrated that the suggested one-platform solution is a reliable and efficient method for the production of high-purity water in the pharmaceutical industry. This system offers an easily maintainable and compact solution, making it suitable for various other industries such as semiconductor manufacturing and electric power generation where purified water with zero TDS is required. By providing a robust water purification process, this solution contributes to enhancing the quality and safety of pharmaceutical products and other critical applications that rely on ultra-pure water.

Assessment of Biological Trickling System with Different Layers of Material for Grey Water Treatment

Greywater reuse is an attractive alternative whenever water resources are scarce because it can lower water demand and increase available water supply. This study used simple, easy-to-find treatment and purification methods to examine how gray sewage from homes could be used in agriculture. The primary motivation for reducing agricultural fertilizer consumption is financial gain. If feasible, society can achieve more acceptable economic objectives. The multimedia biofilter, a biological trickling filter, treats wastewater biologically by attaching biomass to various media. In this investigation, raw greywater was settled for two hours. The same influent was used to compare and contrast two treatment approaches. The treatment methods include an exploration of the effectiveness of two filters. The first filter comprises sand, gravel, cotton, and activated carbon filtration layers. The second contains sand, gravel, brick bat, wood chips, and rice husk filtration layers. Gray water was purified utilizing a sand filtration system (gravel and sand), along with the addition of other materials to improve the effectiveness of the treatment. These additional materials included cotton, active carbon, brick, wood chips, and rice husks. Chemical tests were performed on the graywater, and each component was identified. Overall, the sand-gravel-cotton-activated carbon filter improved greywater quality to irrigation standards by reducing organic matter. The second filter (made of sand, gravel, brick, wood chips, and rice husks) is a low-cost greywater recycling unit. But there is still room for improvement in how well these filters work with higher and changing loads and how long their materials last. As a result, most of the filter materials used were waste products generated inside homes and are said to be the least expensive and most inexpensive filters.

Assessment of solar photocatalytic degradation of textile wastewater by ZnO-based reactors

Abstract The present study deals with treating the textile wastewater of Jodhpur city in Rajasthan, India employing a photocatalysis technique. Jodhpur has a number of textile industries and efficient treatment of its effluents has been a major problem in the region. An effort has been made to resolve this issue through this study. A wastewater treatment unit was setup which involved coagulation and flocculation, sand filter, photoreactor, and activated carbon filter processes. ZnO-based semiconductor, coated on galvanized iron (GI) plates, served as a photoreactor. The water quality parameters removal efficiency at the end of each process operation was recorded for different detention periods in the photoreactor. Water quality parameters analyzed were biochemical oxygen demand (BOD), total dissolved solids (TDS), total suspended solids (TSS), and pH. The optimal retention time for the photoreactor was found and the BOD of the wastewater reduced to 25 from 740 mg/l (97% reduction), and TSS from 1,430 to 12 mg/l (99% reduction) for the corresponding retention time. TDS reduction efficiency was 25% and pH changed from 9.2 in raw wastewater to 8.4 in treated wastewater. Results show that the pilot treatment plant was efficient for BOD and TSS removal from the textile wastewater.

Filter media enhanced electrokinetic remediated crude oil contaminated soil: investigation of its engineering properties and its suitability for road construction

Research have shown how electrokinetic remediation (EKR) technology attempts to tackle the challenge of soil contamination by crude oil. However, the suitability of the resulting remediated soils for use in road construction have not been well reported. This work investigates the engineering properties of filter media enhanced electrokinetic remediated crude oil contaminated soil (COCS) with a view to ascertain its suitability for use in road construction by comparing the performance of charcoal and active carbon as filter materials. COCS collected at a depth of 1m from the Nigerian Pipeline and Storage Company, Kaduna was remediated by using graphite electrodes to pass 1V DC/cm across EKR setups enhanced by incorporating a 1cm thick charcoal and active carbon separately as filter materials across the setups. Average removal efficiencies of 81.4% and 84.6% were obtained against the 78,600 mg/kg oil content of the COCS from charcoal and active carbon filter media enhancements respectively. This showed that active carbon, with higher removal efficiency, is a better filter medium for COCS than charcoal. The compaction and California bearing ratio (CBR) properties of the COCS also improved with the filter media enhanced EKR. However, the CBR values for the filter media enhanced EKR soils only meet the 20% minimum requirements for Type 2 sub-base course materials specified for light trafficked Nigeria roads. As such, charcoal or active carbon filter media enhanced EKR technology can be adopted for remediating COCS for light trafficked Nigeria road construction in areas not subjected to flooding.

Contaminant Removal in a Pilot Drinking Water Treatment Plant by Pre-oxidation Followed by Biological Activated Carbon Filtration: Spiking versus Ambient Studies

Contaminant Removal in a Pilot Drinking Water Treatment Plant by Pre-oxidation Followed by Biological Activated Carbon Filtration: Spiking versus Ambient Studies