Kaduna Refinery Research Articles

Determination of Trace Metals in Petroleum Products Using Atomic Absorption Spectroscopy (AAS): A Case Study of Kaduna Refining and Petrochemical Company Nigeria

The analyses of trace metals in Nigerian petroleum products is very important considering the detrimental effect of these metals in refining processes and environment in general. Also, the data on the concentration of trace metals in Nigerian indigenous petroleum products are limited. This research study aimed at determining and comparing the concentration of trace metals in different Nigerian petroleum products from Kaduna refinery. Trace heavy metals were quantitatively analyzed using atomic absorption spectroscopy; five samples of petroleum products were collected from Kaduna Refining and petrochemical company. Three different preparation methods of analysis were adopted for the determination of trace and heavy metal present in the various petroleum products, viz; direct sample aspiration in to the flame after solvent dilution, Total acid (wet) digestion of the sample, Ashing of the sample and dissolution with an appropriate acid. Sample treatment with organic acid prior to aspiration proved to be more reliable and gave good results for trace and heavy metals in petroleum products except for kerosene sample, where most of the elements responded positively to ashing preparation method. The level of eighteen elements analyzed in petrol (PMS), kerosene (DPK), Automotive Gas Oil (AGO), LPFO (Low pour fuel oils) and Residual Fuel revealed that potassium and sodium are the most abundant elements in both the five sample under study followed by iron, manganese, lead and aluminum. which revealed that Potassium (120 mg/l, 340 mg/l, 120 mg/l, 2900 mg/l, 2050 mg/l) and Sodium (260 mg/l, 180 mg/l, 160 mg/l, 1800 mg/l, 1200 mg/l) are the most abundant elements in both the five sample under study followed by Iron, Manganese, Lead and Aluminum respectively. The concentration ranges of trace heavy metals analyzed are within the permissible levels set by World Health Organization.

Influence of Microbial-Induced Calcite Precipitation on Compaction Characteristics of Bioremediated Crude Oil Contaminated Soil using Composting Technique

Compaction as a soil improvement method of improving the engineering performance of soil was carried out on remediated contaminated soil with the aim of assessing the influence of microbial induced calcite precipitation (MICP) on compaction characteristics. Autochthonous bacteria was identified as Bacillus licheniformis and isolated from oil contaminated soil, collected from Kaduna refinery at Area W where the crude oil was stored. The bacteria were enhanced with organic liquid nutrient extracted from chicken droppings (CD) in stepped concentration of 10, 20, 30, and 40% by dried weight of soil sampleand used to hydrate the contaminated soil. The mixtures were kept in four microcosms for 3 months. The initial total hydrocarbon content was 98g/kg. The bioremediated soil was treated with bacteria solution through MICP technique. The results revealed that sample treated with 30% CD yielded the highest removal efficiency of 89.8% of oil removal. Maximum Dry Density increased with addition of B. licheniformis solution to a peak value of 1.93Mg/cm3 for sample treated with 1.5×108 cell/ml. Optimum moisture content (OMC) increased with increased in B. licheniformis suspension from 14.4 to 15.8% when treated with 1.5×108 and 2.4 ×109 cell/ml respectively. Compaction characteristics of soil treated with 30% CD were greatly improved at 1.5×108 cell/ml bacteria solution using MICP technology and could be used as liner material in waste management.

Downstream Effects of Industrial Effluents Discharge on Some Physicochemical Parameters and Water Quality Index of River Rido, Kaduna State, Nigeria

The effects of industrial effluent discharge on the water quality of River Rido in Kaduna South, Kaduna State, were examined. These include the Northern Noodles discharge point, the Kaduna Refinery discharge point, and points downstream of the River Rido. An interval of 100m between sampling points was established to achieve an even representation of sampling points. The physico-chemical parameters investigated include pH, free dissolved carbon dioxide, alkalinity, hardness, sodium, electrical conductivity, Turbidity, total suspended solids, total phosphate, nitrate, sulfate, and dissolved oxygen. Mean levels of turbidity Total suspended solids and total phosphate at effluent discharge points, as well as in most areas downstream of the study area, were generally above permissible limits for drinking water. Statistical differences were observed in the concentration levels of investigated parameters between the control point and effluent discharge points, as well as between the control point and areas downstream of the study area. However, concentration levels were observed to be similar between discharge points and areas downstream of the study area, an indication of contamination downstream by effluent discharge upstream. Notwithstanding, the water quality index of physico-chemical parameters at both effluent discharge points and areas downstream of River Rido shows that the quality of the river ranged from good to excellent at effluent discharge points and areas downstream of River Rido, respectively. This might be attributed to the effect of dilution from rainfall. It is therefore recommended that wastewater effluent from the refinery and northern noodles be properly treated before discharged into the study area.

Investigation of Naphtha Hydrotreating (NHT) Unit Exergy Utilization: A Case Study of a Petrochemical Industry in A developing Country

The need for efficient energy use in refinery operations is the proffered solution to the poor management of energy resources which has resulted in the instability in oil products prices, irregular plant shutdowns experienced in refineries of developing countries and increased carbon emission to the atmosphere. This research work aims to carry out exergy analysis on major energy consuming units which will aid in determining sites and causes of primary energy losses and proffer solutions to maximizing energy utilization. The Naphtha Hydro-treating (NHT) unit of the case model refinery was successfully simulated using Aspen Hysys. The analysis revealed more than half (51.9 %) of the input exergy was lost to the environment and an irreversibility of 32.7% occurred in the Stripper column. Comparison was also made with the same unit at Kaduna refinery and petrochemical plant and the results showed a conversion efficiency of about 91.28% when compared to 44.35% from the old refinery though this could be attributed to factors like age of plant, inadequate maintenance etc. The positive value of the amount of heat recovered from that of the flue gas in the boiler and furnace gave an opportunity to recover the energy lost and integrated back to the system for economic viability of the plant which result in a payback period that is less than a year.

Assessment of Bioaccumulating Ability of Mariscus longibrateatus and Effects of Effluents from Kaduna Refinery and Petrochemical Company on the Plant

The operations of Kaduna Refinery and Petrochemical Company (KRPC) lead to the generation of effluents. Plants growing in the drain are in constant exposure to these effluents. Mariscus longibrateatus, which is the most abundant plant species growing in the drain, was studied to determine the effects of the effluents on the plant. Plant samples and soil on which the plant grows, were analyzed for heavy metals. Manganese (1.30mg/g) and copper (1.30mg/g) had the highest concentration of heavy metals in the roots. The plant samples had thinner leaves than the control plant, which may be attributed to dehydration and some hidden injuries. The leaf whole vascular bundle of the studied plants ranged from 19085–20790µm2 whereas phloem and xylem area ranged from 3995 – 4290µm2 and 6584-7004µm2 respectively. Transfer and bioaccumulation factors revealed that heavy metals were not effectively transferred from the root to the stem, but the plant was able to survive in the drain containing KRPC effluents. It is concluded that the effluents caused some changes in the plant. It can be inferred that Mariscus longibrateatus are tolerant to the toxicants in the effluents, and therefore, this plant species is recommended for bioremediation study because of its tolerant ability to heavy metals.

Assessment of Aquifer Protective Capacity, Against the Surface Contamination. A Case Study of Kaduna Industrial Village, Nigeria

Geo-electric soundings was carried out in 22 different locations at Kaduna Refinery Petrochemical Corporation (KRPC) and White Oil and Gas Layout, Mahuta, Kaduna. The aquifer protective capacity and Hydraulic characteristics of the study area was computed from the Geoelectric parameters using Dar-Zarrouk and hydrological parameters. The interpreted data were presented in tabular form, Geoelectric/geology soil profiles and contoured maps. The results show that the study area aquifer is relatively protected with an average value of 0.5 mhos with an indication of infiltration of contaminant in some location. The hydraulic parameter values also show that the study area aquifer has the capacity to produce water non-stopping if the wells are sited based the geophysical investigation. The computed hydraulic characteristics and transmissivity of the area has an average value of 5.5 m/day and 6.1 /hour, which implies that, the study area has the capacity to transmit groundwater through a distance of 5.5 m in 24-hour and can covers 6.1 in one hour.

Gaseous Emission from the Combustion of Premium Motor Spirit (PMS) from the Kaduna Refinery and Petrochemical Company (KRPC) in Nigeria

Objectives : This study characterizes the gaseous emission from the combustion of PMS of different volumes from Kaduna Refinery and Petrochemical Company.Methods : The E8500 plus combustion analyzer was used for gaseous emission characterization of different volumes. Oxygen (O2), Hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), Oxides of Nitrogen NOx (NO, NO2), Sulphur dioxide (SO2), and Hydrogen Sulfide (H2S) were measured using the analyzer. The values were recorded and the descriptive statistics graph was plotted.Results and Discussion : The concentrations for the gaseous emission from the combustion of PMS were 69.85 mg/m3 HC, 117.33 mg/m3 CO, 334 mg/m3 NOx for 10 ml, 58.93 mg/m3 HC, 130.33 mg/m3 CO, 784.33 mg/m3 NOx for 20 ml, 50.20 mg/m3 HC, 84.00 mg/m3 CO, 798.67 mg/m3 NOx for 30 ml, 65.48 mg/m3 HC, 160.33 mg/m3 CO, 850.33 mg/m3 NOx for 40 ml, 87.31 mg/m3 HC, 212.67 mg/m3 CO, 801.33 mg/m3 NOx, 3.67 mg/m3 SO2 for 50 ml. This study shows that CO and HC exceeded the permissible limit for stationary sources while NOx and SO2 were below the permissible limit.Conclusions : Hence, there is a need for rapid response and urgent attention from government and regulatory bodies to develop and implement appropriate policies that will help in reducing the effect. Appropriate measures to control air emissions that may be embarked upon by regulatory bodies include increase in the use of low-emission fuels and renewable fuels such as bio-fuels and introduction of the use of devices with low CO emissions.

Gaseous Emission from the Combustion of Dual Purpose Kerosene (DPK) from the Kaduna Refinery and Petroleum Company in Nigeria

Kaduna Refinery and Petroleum Company convert crude oil and other liquids into refined petroleum products. These petroleum products are used in our various homes as a source of energy but they can be a threat to human lives and the ecosystem. Gaseous emissions from the combustion of DPK of different volumes from Kaduna Refining were characterized for gaseous air pollutants using the E8500 combustion analyzer. The concentrations for the gaseous emission from the combustion of DPK were 34.92mg/m3 HC, 21.67mg/m3 CO, 89.00mg/m3 NOx for 10 ml. 41.47mg/m3 HC, 33.33mg/ m3 CO, 118.33mg/m3 NOx for 20 ml. 52.3 mg/m3 HC, 49.33mg/m3 CO, 183.33mg/m3 NOx for 30 ml. 50.20mg/m3 HC, 33.00mg/m3 CO, 189.33mg/m3 NOx for 40 ml. 61.12mg/m3 HC, 40.62mg/m3 CO, 199.00mg/m3 NOx , 2.6 mg/m3 SO2 for 50 ml. This study shows that CO and HC exceeded the acceptable limit for stationary sources while NOx and SO2 were below the acceptable limit. Hence, there is a need for rapid response and urgent attention from government and regulatory bodies to put in place policies that will help minimize the effect of these emissions.

Screening of Fungi Isolates from Kaduna Refinery Effluent and Romi River and Their Potential for Bioremediation

The operation of Kaduna Refinery and Petrochemical Company (KRPC) has increased effluent generation with consequent effects on water quality and habitat since it is discharged into nearby receiving water body. These effluents contain heavy metals and other toxicants. Samples were collected from the effluent discharge point of the Kaduna Refinery and Petrochemical Company (KRPC) and from Romi River located at Kaduna South Local Government Area of Kaduna state. Standard methods were used to analyze the physicochemical parameters and heavy metals of the effluents. A total of 14 fungi isolates were identified from the samples. These fungi isolates were screened for their bioremediation potential on some toxic components in refinery effluent and were identified using molecular techniques. Four fungi isolates (Chrysosporium tropicum, Aspergillus flavus, Aspergillus niger and Rhizopus oryzae) were selected for bioremediation. Carbon (IV) oxide evolution increased progressively during the period of bioremediation. There was a noticeable decline in the phenol, lead, cadmium and nickel in the entire bioremediation medium. There was a positive correlation between phenol and cadmium with a coefficient of 0.969. Consortia of fungi isolated from the refinery effluent and Romi River samples were effective in the bioremediation of refinery effluent. The mixed consortium of four fungi showed the most efficacies in the bioremediation of refinery effluent in terms of phenol, oil and grease, cadmium, lead and cadmium reduction. Kaduna Refinery and Petrochemical Corporation (KRPC) should adopt bioremediation as one of the techniques in treating effluents before being discharged into receiving water bodies
 Keywords: Effluents, Fungi, heavy metal, bioremediation.

ENVIRONMENTAL IMPACT ASSESSMENT OF HEAVY METALS EFFLUIENT (CHROMIUM & NICKEL) RELEASED INTO ROMI RIVER, KADUNA STATE: A CASE STUDY

Industrial effluents discharged into the river poses a serious threat to our environment; the research examines the impact of some heavy metals of Kaduna refinery effluent into the Romi River. It asserts the nature of effluent released into the water body and also the impact of effluent on water quality. However the important water quality became relatively slowly as early human could only judge water quality through the physical senses of sight, taste and smell, now a days there is an increase of contamination of natural water bodies by industrial effluents in developing and densely populated countries like Nigeria, because rivers are major means of waste disposal and especially effluents from industries nearby. The data used in this research were generated from direct field measurement of pH, Conductivity, and Turbidity, heavy metal profiles (Chromium & Nickel) from Kaduna Refinery Effluent. The mean concentrations of the metals; chromium, iron, nickel, and zinc with the standard deviation were found to be: < 0.01 ± 0.1 mg/kg, and 0.06 ± 0.1 mg/kg. This study has shown that the mean concentration of chromium and Nickel found to be lower than the World Health Organization (WHO) acceptable limits while the concentration values of nickel 0.06 ± 0.1 mg/kg and iron 0.06 ± 0.1 mg/kg as found to be higher than the WHO, acceptable limits of the metals) obtained at the effluent points and this implicate the industry adjacent to the area as one of the sources of heavy metals in the river.

Effect of hydrogen partial pressure on catalytic reforming process of naphtha

The semi catalyst regenerative commercial naphtha catalytic reforming of Kaduna Refinery, Nigeria is modelled and simulated with general process modelling systems (gPROMS) model builder 5.0.0 which is a computational tool in modelling process and complex chemical engineering processes. The thermodynamic and kinetics parameters used are obtained from the referenced literature. The model was validated with data from literature and was used to simulate the commercial data of KRPC. Simulation results obtained were good compared with the plant and literature data and these results were used in monitoring the plant performance and the temperature and concentration profiles of the parafins, naphthenes and aromatics as they change across the reactor bed heights. Hydrogen partial pressure effect on the product quality, aromatics and product yields were studied. It was found that an increase in hydrogen hydrocarbon ratio of 5.6 to 7.4, aromatics yield decrease from 58.5% to 55.5%, reformate yield increases from 52,805 kg/h to 53,234.5 kg/h, hydrogen yield increases from 10,955 kg/h to 14,515 kg/hr. The percentage weight of coke on the catalyst decreases with increase in hydrogen hydrocarbon ratio of 5.6 to 7.4 from 1.8%wt to 1.289%wt, 3.297%wt to 2.415%wt, 4.457%wt to 3.351%wt and 5.1850%wt to 3.983%wt for reactors 1, 2, 3 and 4 respectively.

Extent and Rate of Changes in Landuse/Landcover Around Kaduna Refining and Petrochemical Company, Chikun Local Government, Kaduna State

<p>Anthropogenic activities on land resulted in landuse/landcover change including vegetation. Landuse changes play a role in the sustainability of refinery because of associated environmental effects. Moreover, there is growing societal concern about the spatial and temporal scales of some types of conversions, such as deforestation and urbanization. This paper determine the extent and rate of changes in landuse/landcover as a result of establishment of Kaduna Refinery and petrochemical company. The study employed the used of Remote Sensing and GIS techniques in acquiring and analysing the data respectively. The 1974 Landsat 4 Multispectral Scanner (MSS) 60m resolution, 1986 Landsat 5 Thematic Mapper (TM) 30m resolution, 1999 Enhanced Thematic Mapper Plus (ETM+) 30m resolution and 2018 Landsat 8 Operational Land Imager (OLI) 30m resolution images were used. A supervised Image classification method was used because of its high accuracy. This was carried out using ArcGIS 10.5 software. The built-up areas were constantly increasing, while vegetation and agricultural land were decreasing proportionally due to clearance to make room for the industry and settlements for staff and refinery attracted population. There is need for establishment of a programs that promote tree planting, must especially the exotics ones as they are the most threatened species in the area. The present agricultural land need to be preserve and new ones need to be open and expanded in order to improve the agricultural activities of the area.</p>

ESTIMATION OF THE ABUNDANCE AND DISTRIBUTION OF RARE EARTH ELEMENTS IN SOIL AROUND KADUNA REFINING AND PETROCHEMICAL COMPANY USING NUCLEAR TECHNIQUE

Instrumental neutron activation analysis (INAA) technique was used to investigate the abundance and distribution of rare earth elements (REE) in soil around Kaduna Refinery. The aim of the study is to assess the rare elements potential of Nigeria for economic exploitation. Five REEs (La, Dy, Eu, Yb, and Lu) were detected in varying concentrations ranging from a minimum of 0.6 µg/g (Lu) to a maximum of 249.0 µg/g (La). The elements existed with trends consistent with the natural pattern of REEs in soil, showing significant Eu and Dy anomalies which characterize upper plains and flood plains. The levels of REEs in soil in the study area were generally slightly above background levels, with minimal (La, Dy, and Eu), moderate (Yb), and significant (Lu) enrichments and trending: Lu ˃Yb ˃ Eu ˃ Dy ˃ La. The abundance of the REEs investigated cannot establish a potential of Nigeria for economic exploitation of the mineral, hence, rare earth project in the study area is not viable at the moment.

Exergy analysis of Naphtha Hydrotreating Unit (NHU)

The aim of this research work is to develop an exergy analysis of Naphtha Hydrotreating Unit of the Kaduna Refinery and Petrochemical Company (KRPC). This was achieved through extraction of data from the Laboratory operating manual and the process flow diagram of the naphtha hydrotreating unit of the refinery which is used in the simulation; the site of primary exergy destruction was also determined. The major components of exergy efficiencies of the major component were determine. Also the potential for process improvement through revamp was determined. Exergy analysis of Naphtha Hydrotreating Unit (NHU) of the Kaduna Refining and Petrochemical Company was successfully simulated using Aspen HYSYS. Exergy efficiencies were found to be very low in Heaters 11H01 and 11H02 at 23.9% and 50.0% respectively. Similarly low efficiencies were respectively observed in Columns 11C02 and 11C01 at 48.7% and 52.8%. The major contributors to exergy destructions were found to be Column 11C01 and Heater 11H01 with percentage contribution of 21.6% and 14.6% respectively, totaling 36.2% of the total irreversibility recorded in the NHU process. Heat recovery from flue gas in the furnace and boilers was considered and found to be economically viable with a payback period of less than one year.

Evaluation of the Variation in the Level of Compliance of Kaduna Refinery and Petrochemical Company (KRPC)

This study evaluates the level of compliance of Kaduna Refinery and Petrochemical Company (KRPC) to United Nation Environmental Safety Standard for effluent Management. Waste water samples were collected from eight sampling points within the study area which comprised of the following: effluent sample before treatment, effluent sample after treatment, KRPC effluent discharge point, a point downstream after the refinery facility, and 4km downstream after the refinery facility. The data collected were subjected to Laboratory analysis in the Kaduna Environmental Protection Authority Laboratory. The results generated from laboratory analysis were then subjected to statistical analysis which included ANOVA and Plots of mean variation. Research findings revealed that most of the parameters measured show a significant variation between the sampling points and within the months. The plots of mean variation on the other hand show that the concentration of these parameters varies progressively with distance from the point of the refinery facility. The following recommendations would minimize the load of pollutants on Romi River; the activities of other industries in Romi-Rido environs should be critically identified and assessed; and there is a need for the National bodies entitled with the role of assessing the activities of industries to develop a form of sanctioning against any industry that refuses to adhere to the standard environmental protection legislation, among others.

Screening of Biosurfactant-Producing Bacteria Isolated from River Rido, Kaduna, Nigeria

Biosurfactants which are produced by microorganisms, are known to reduce the surface tension of viscous liquid. Among the roles of biosurfactants is solubilization of hydrophobic substrates especially petroleum. River Rido is a point where petroleum-rich effluents from Kaduna Refinery and Petrochemical Company are discharged. There is need to isolate and characterize bacteria capable of producing biosurfactant from River Rido, Kaduna, which will serve as a tool for bioremediation. Water samples contaminated with refinery effluents were collected from four different sites along River Rido. Biochemical tests revealed that the bacteria isolated from the water sample belong to the genera of Bacillus (36.36%), Pseudomonas (27.27%), Corynebacterium (18.18%) and Streptococcus (18.18%) species. The isolates were coded as BS1 – 11. Among the bacteria, 18.2% showed α-haemolytic activity, 54.5% showed β-haemolytic activity and 27.3% showed γ –haemolytic activity. BS1, BS2, BS4, BS6, BS7 and BS11 showed positive results for oil spreading test. BS1, BS2, BS4, BS6, BS7 and BS11 were all positive for the drop-collapse assay. Isolates BS1, BS2, BS4, BS6, BS7 and BS11 were able to emulsify crude oil. Analysis of Variance revealed that there is a significant difference in the emulsification activity of the isolates at various pH levels. Also, emulsification index of the isolates at varying temperatures are significantly different. This study revealed that Bacillus species, Corynebacterium spp . and Pseudomonas spp . isolated from River Rido have been confirmed biosurfactant producer with ability to produce assayable biosurfactants and can be useful tools for various environmental and industrial processes, especially in the area of bioremediation of oil pills. Keywords : Biosurfactant, Emulsification, River Rido and Bacteria

Evaluation of the impact of Kaduna refinery effluent on river Romi

The continuous global quest for management of the scarce water resources to make available to the human populace. portable water for drinking has necessitated this study. River Romi is the effluent discharge point of Kaduna Refining and Petrochemical Company Limited where the refinery waste water is disposed after treatment. This study investigates the impact of Kaduna refinery eflluent on River Romi. The physicochemical properties of Kaduna River, Kaduna refinety eflluent, Romi River (upstream and downstream) were analy=ed f rom dry and wet seasons. The results obtained were compared with standard set by regulatory bodies and it was discovered that Kaduna refinery eflluent has the highest number of pollutants. The body of River Romi upstream was found to contain low level of contaminants which are generally within the standard limits. Comparing the results of both upstream and downstream of River Romi shows that the concentration of pollutants increased after the introduction .of eflluelll

Optimization of Water Reuse Network Using Water Pinch Technology (WPT) by Considering Single Contaminant for Kaduna Refinery and Petrochemical Company, Nigeria

Conventionally, freshwater has been the only source of water for processes used in the industries due to the fact that it is cheap, and the wastewater generated in these processes has been treated in a central common facility in order to remove contaminants and to meet regulatory specifications for wastewater disposal. This research identify an optimum design of water reuse network for Kaduna refinery and petrochemical company (KRPC), while considering suspended solid (SS), hardness (H, Chemical oxygen demand (COD) and Free hydrocarbons (FH) wastewater contaminants and analysing the feasibilities of reuse and recycling for water and wastewater minimization in the water network of the company by using graphical method known as Water Pinch Technology (WPT). The analysis indicated the possibility of reducing the fresh water use by 76.8 m3/h (32.3%) if Free Hydrocarbons (FH) was considered as the reference contaminant.

Vertical subsurface flow constructed wetlands for polishing secondary Kaduna refinery wastewater in Nigeria

Secondary wastewater discharged by the Kaduna refining and petrochemical company in Kaduna (Nigeria) was characterized and treated in six vertical subsurface flow constructed wetlands (VSF CW) under field conditions. The secondary refinery wastewater had high levels of BOD (106±58.9mg/L), COD (232±121.2mg/L), TSS (86.1±99.7mg/L), TDS (278.8±112.7mg/L) and a turbidity of 56.8±59.2 NTU. Cyperus alternifolius and Cynodon dactylon (L.) Pers. were planted in four VSF CWs and the last two VSF CWs served as the unplanted control. Good reduction efficiencies in the concentration of the contaminants were achieved which corresponds to removal rates of 54%, 85%, 68%, 65%, 68%, 58% and 43% for TDS, turbidity, BOD, COD, ammonium-N, nitrate-N and phosphate-P respectively, for the C. alternifolius planted vertical flow constructed wetland and 50%, 82%, 70%, 63%, 49%, 54% and 42% for the C. dactylon planted wetland system. Hence, C. alternifolius and C. dactylon planted VSF CWs were shown capable of treating secondary refinery effluent to discharge permit limits. For most of the parameters considered, the performance of the C. alternifolius and C. dactylon planted vertical flow constructed wetland systems was not significantly different from each other, however, they performed significantly better than the unplanted control.

Resistance to some Heavy Metals among Fungal Flora of Raw Refinery Effluent

Investigations were carried out to assess the capacity of strains of fungi isolated from raw flowing effluent and effluent retention pond of Kaduna refinery plant to resist and grow in the presence of lead (Pb), nickel (Ni) and cadmium (Cd) invitro. Fungi belonging to the genera including Aspergillus spp., Penicillium spp., Fusarium spp., Curvularia spp. and Nigrospora spp. were isolated from the study sites. The isolates were inoculated into duplicate 100ml flask containing 50ml of potato dextrose broth (PDB) supplemented with 5,10 and 15ppm of Pb, Ni, and Cd. Each test isolate was inoculated into duplicate flask containing the same medium without the heavy metals to serve as control. All inoculated flasks were incubated aerobically at room temperature on a rotator shaker for 7days. The mycelial mats were harvested by filtering the cultures through preweighed filter paper (No.1). The filters bearing the mycelial mats were dried in an oven at 70oC for 18hours. It was observed that most of the isolates tested resisted and grew in the medium containing 5 to 15ppm of tested heavy metals. Yield of dry mycelia mats in the heavy metal supplemented medium were also comparable to those grown in heavy metal free PDB medium. It was concluded that, these genera of fungi could be playing an important role in the removal of these metals usually present in the raw effluent during the period of residency in the retention pond through bioaccumulation. ©JASEMKeywords: Fungal flora, Heavy metals, Resistance, Refinery effluents