J.K. Wahane, K.R. Magardhe and O.N. Choubey*
Department of Chemistry, Govt. Narmada P.G.College, Hoshangabad M.P. 461001, India
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Impact of Soya solvent extraction plants on local groundwater of nearby industrial area of Betul district was studied. It was observed that the concentration of TDS, EC, Hardness, Chloride, Phosphate, BOD, COD, were higher in the groundwater samples.
DO, BOD, COD, Fluoride, Phosphate, Hardness, Alkalinity, pH, Extraction, ETP
Soyabean is world’s one of the most useful and cheapest source of protein. The botanical name of Soyabean is Glycine max. M.P. has emerged as the Soya state in India. Major portion of Soyabean is cultivated in M.P as compared with overall production in India. There are a number of Soya solvent extraction plants in the state. The composition of soybean constituent are moisture (11% Max) protein (48% min), fat (1.57% Max) Fiber (6.5% Max) sand/ silica (2% max) Urease (.30% Max). In this paper the adverse impact of chemicals used and discharged through ETP in Soya Industry on local groundwater has been studied.
Oil extraction process
Soyabean is mainly used for Soya oil and vanaspati as cooking oil. The steps used for oil extraction are cleaning, cracking, cooping. Seeds are heated through jacked steam and open steam to soften the seeds. The seeds are flaked between two rollers then flakes are dried using hot air. The dried flakes are sent to extractor and Hexane is sprayed on material to extract oil. The hexane condensed out and recycled to the process. The crude oil extraction is heated up to 50°C to 60°C . Water and phosphoric acid is added. To remove the phosphate, gum and free fatty acid from the oil. Caustic soda is used to neutralize it. The bleaching agent is used to remove colour. Lastly oil is then deodorized by heating at 220°C in the above oil extraction process major chemicals used are hexane, phosphoric acid, bleaching agent and caustic solution. The effluent of the process is discharged in ETP for treatment and the treated effluent finally is used for irrigation or discharged which can affect the ground water quality.
Sampling site and Analysis
The samples were taken from in side and near by area of Betul Oil & Flour Mill throughout the year. APHA (1995) and Trivedy and Goel (1986) have been used for the analysis of ground water for pH, Electric conductance TDS, Turbidity, Alkalinity, Total Hardness, Calcium and Magnesium Hardness, Chloride, Fluoride, Nitrate, Sulphate, DO, BOD, COD and some Heavy metals like copper, Zinc, Iron and manganese.
pH of all water samples was found to range between 6.3 to 7.5. The samples collected from the Industrial area and inside the Soya plant were found acidic in nature. Electric conductance is a measure of water capacity to convey electric current. The specific conductance of all samples is above the permissible limit (300 mg/L) of WHO indicating the contamination of water through waste. High TDS value is responsible for high concentration of minerals. Concentration of TDS can also be estimated on the basis of electric conductivity measurement. Hardness of water increases due to presence of carbonate and bicarbonates ions in ground water. We observed high value of COD in all water samples throughout the year Fig. 2. BOD is also high in all water samples throughout the year. These values are much above n the limiting values indicating danger for domestic uses.
Chloride in drinking water is harmless if present below 250 ppm but its higher value at some stations causes harms to metallic pipes and crops Chloride value of all samples are above 250 ppm. Phosphate values of all samples are higher then permissible limit. Shown in Fig. 1. It is due to excess addition of phosphoric acid during oil extraction process of the plant. We observed the Nitrate value of some water samples are above the permissible limits Fig. 3 shows excess of Nitrates it is particularly dangerous to infants less than six month’s causing child disease methemoglbi methemoglbinaemia. During the analysis of heavy metals in the year 2007-2008 we observed the value of Cu & Zn, with in the permissible limit but the value of Fe & Mn. was above the permissible limit. When the value of Fe is increased in water their taste and odour can be changed.
Reasons for high value of these parameters are due to the accumulation of minerals, salts from the industrial waste water to the soil and leaching to the ground water.