*1 esosa.imarhiagbe@uniben.edu/07034482706 ENVIRONMENTAL ASSESSMENT OF EFFLUENT QUALITY FROM A VEGETABLE OIL PROCESSING PLANT IN EDO STATE, NIGERIA. Emmanuel Esosa Imarhiagbe*1, Osayomwanbo Osarenotor1 and Aimuanmwosa Frank Eghomwanre1 1Department of Environmental Management and Toxicology, Faculty of Life Sciences, University of Benin, PMB 1154, Benin City, Nigeria.   *1 esosa.imarhiagbe@uniben.edu/07034482706

INTRODUCTION Over the years, the economic progression in Nigeria has led to the establishment of sporadic increase in the diverse types of industries and concomitant increase in the level of pollution in the environment. Industrial effluents are liquid wastes which are produced in the course of industrial activities especially during production. Agencies of the Federal Government of Nigeria such as Federal Environmental Protection Agency (FEPA) have established guidelines and standards for industrial emissions and effluent discharges. Industries are therefore, required by law to monitor their effluent to ensure compliance when compared to established regulatory standards.

RATIONAL TO STUDY The improper disposal of industrial effluents is an issue and a source of concern to both government and environmentalists. According to Okereke (2007), in most developing countries like Nigeria, governmental imposed effluent quality standards are sometimes easily flouted. The consequence of these anomalies is a high degree of environmental degradation and health hazard.

AIM/OBJECTIVE OF STUDY The main objective of this study was to evaluate the quality of the effluent discharges from a vegetable oil processing plant located in Edo State, in order to determine its compliance with statutory standard.

Materials and methods Duplicate effluent samples were collected from the discharge pond (point A) and flowing canal (point B) using one litre polythene containers and 250 ml sampling bottles from January 2013 to November 2013. Samples were collected for physico-chemical and microbiological analysis. Physico-chemical parameters: All physico-chemical parameters were analyzed using standard analytical procedures (APHA, 1995). Analysis of heavy metals: Heavy metals were analyzed using Atomic Absorption Spectrophotometer (AAS) Buck Scientific (Model 610). Microbiological parameters: Microbial parameters were total coliform counts (MPN/100 ml) and total heterotrophic bacterial counts. Analyses were carried out with reference to Cheesbrough (2000) and APHA (1995).

RESULTS AND DISCUSSION

Table 1: Physico-chemical parameters of bi-monthly effluent samples PHYSIO CHEMICAL PARAMETERS January March May July September November FEPA limit 1991 Point A Point B Point B PH 9.80 6.20 10.18 7.81 9.66 6.31 8.87 7.03 6.53 6.24 9.37 6.78 6.0-9.0* Total Suspended Solids (mg/l) 15.34 11.0 10.8 10.0 15.0 10.63 13.5 13.0 12.0 30mg/L Total Dissolved Solids (mg/l) 1900 1800 1400 1200 1390 1380 2131 1282 1440 1320 1210 2000 mg/L* Phosphate (mg/l) 0.067 0.032 0.095 0.062 0.064 0.052 0.12 0.09 0.45 0.14 0.53 <5 mg/L* Hardness (mg/l) 1.32 1.28 7.62 4.07 0.34 0.28 0.44 0.32 0.68 0.33 1.78 1.34 NS Calcium (mg/l) 4.50 2.24 255.7 48.09 22.8 11.2 60.0 5.51 3.0 210.4 170.3 200 mg/L* Magnesium (mg/l) 4.30 2.62 30.13 7.29 0.27 10.93 3.64 2.73 0.9 30.35 6.08 200 mg/L Dissolved oxygen (mg/l) 1.42 1.35 1.8 1.7 1.0 1.72 1.5 Not < 2 mg/L* Biochemical Oxygen Demand (mg/l) 85.0 65.4 80.0 55.4 84.71 64.0 54.7 85.5 92.32 61.2 94.2 64.5 30 mg/L* Chemical Oxygen Demand (mg/l) 240 160 220 132 214 264 174 200 181 288 151 80 mg/L*

Table 2: Heavy metals of bi-monthly effluent samples   January March May July September November FEPA limit 1991 Point A Point B Copper (mg/l) 0.00 <1 mg/L Lead (mg/l) 0.01 0.02 Iron (mg/l) 0.70 0.63 0.76 0.52 0.87 0.56 0.25 0.20 0.08 0.05 20 mg/L Nickel (mg/l) Zinc (mg/l)

Table 3: Microbiological analysis of bi-monthly effluent samples PARAMETERS   January March May July September November EPA limit 1991 Point A Point B Point B Total Coliform Count (MPN/100ml) 180 120 140 <400 Total Heterotrophic bacterial count (105cfu/ml) 19.5 13.0 20.3 17.3 28.0 20.5 19.0 12.5 19.6 NS

Table 4: Predominant bacterial isolates from bi-monthly effluent samples   S/N Bacterial isolates 1 Pseudomonas spp. 2 Acinetobacter sp. 3 Micrococcus sp. 4 Staphylococcus spp. 5 Enterobacter sp. 6 Bacillus spp.

RELEVANCE OF RESULTS OBTAINED From the results obtained, it can be observed that the values were higher in point A (discharge point) than those of point B (flowing canal). That effluent from vegetable oil plant contains low concentration(level) of all heavy metals analysed and were below the permissible limit. That the composition of this effluent-type has the potential to enhance the growth of microorganisms.

CONCLUSION This study reveal that the effluent from this processing plant did not comply with prescribed standards, being oxygen and chemical demanding, low in dissolved solutes as well as exceeding the prescribed pH limit. Thus, there is need for proper effluent treatment and monitoring to improve quality.

RECOMMENDATIONS There is the need for proper monitoring and enforcement of laid down standards by appropriate regulating agencies. Concerned industry should ensure training and re-training of their personnel in charge of environmental schedules. That concern industries should establish environmental laboratory with trained personnel who will be saddled with the responsibility of monitoring the effluent quality.

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