The total effluent generated per day amounts to an average of 50 – 70 kilo litters. The plant effluent generated is divided into two streams viz., industrial effluent stream and sewage effluent stream which are mixed prior to the treatment
Conventional treatment method – A Description
The industrial effluent stream is collected in collection tank of 180 kL (Kilolitres) capacity and them giving even mixing by aeration from where it is transferred into a flocculation tank. In the flocculation tank, alum and polyelectrolyte are added so that all the inorganic substances in the effluent water are coagulated and made into thick flocs. The sediments thus formed are removed by passing through an inclined plate clarifier. Then the remaining water sends it to DAF (Dissolved air floccation) for separating oil scum. After DAF treatment wastewaters, send it to air equalization tank for maintaining pH at 7 by adding caustic. This waste water transfer to buffering tank and added known amount of caustic, bicarbonates, cobalt, nickel and ferric chloride for increases pH and maintaining around pH 7.75. This buffering tank wastewater pumped to anaerobic chamber II and I for digest organic materials, after anaerobic treatment treated effluent and the sewage effluent (collected separately in an equalization tank of 15 Cu.M. capacity) pumped into the aeration tank. Constant aeration and mixing is employed to make the contents homogeneous. The biological activity taking place in the aeration tank converts the organic load into carbon dioxide and linked to pre-aeration tank and giving proper mixing for sledge settling inside the tank. Then the over flow pure water again pump it to second clarifier (recycling) overflowing from the inclined plate clarifier is allowed to pass on to the aeration tank. After clarifier, this water filtered by sand filtration technique and stored into open tank for evaporation.
The characteristic raw effluent produced by this confectionery industry are characterized by their organic content; most are composed of easily biodegradable compounds such as sugars, sweeteners, casein, vegetable oils, acacia gums, condensed milk, food coloring and flavoring agents, etc. This confectionery industry using major ingredients such as sugar and sweeteners, natural colors, acacia gum, sugar substitutes, gum base and flavors for all type of confectionery products. They use number chemicals during the process and they all become a part of the effluent. This liquid effluent is acidic in pH, dominated by yeast cell population.