RULES OF POULTRY ABATTOIR WASTEWATER WITH DIFFERENT COMPOSITION BY COAGULATION

Abstract

Poultry slaughter house wastewater is highly polluted and must be pre-treated at local wastewater treatment plant before their discharge into sewer. This wastewater contains a large amount of various contaminants such as fluff, feather, blood, canyga, sand, grease, detergents, etc. All these contaminants are found in wastewaters in high concentrations and the discharge of insufficiently treated or untreated wastewater leads to decrease of efficiency, and sometimes to complete failure of wastewater treatment plants. There is technological scheme with buffer tank with mechanical or pneumatic mixing, pump station, coarse screens and flotation unit with preliminary reagent treatment most widely used. With a properly tuned technological mode, this scheme shows a fairly high and stable cleaning efficiency. The most problematic and difficult unit of this technological scheme is reagent treatment. In general, reagent treatment is represented by coagulation with pH adjustment and subsequent added of flocculants. There are iron and aluminum salts, numerous of new organic coagulants widely used as coagulants. The complexity of chemical treatment consist of debugging of technological regime of the local treatment plants, because doses of reagents, their types and conditions of use can be radically different even between factories which using the same technology. This is due to many factors ranging from the culture of production and ending with the quality of the process water which factory use. There are rules of coagulation process of poultry abattoir wastewater from two factories which use similar technology shown on this paper. At the same time, more modern equipment was installed at one of the factories, and that’s why the water consumption is lower and the concentration of pollutants in wastewater is higher. So at the factory with more modern equipment the suspended solids concentration at the inlet is 2500 mg/l, and at the older factory - 800 mg/l. This article is studies the patterns of coagulation of wastewater from a meat processing plant using three types of coagulants: ferric chloride, ferrous sulphate, aluminum polyoxychloride. The study was conducted in two stages. At the first stage, relations of coagulation of pH of wastewater were determined experimentally in a wide range and graphics were obtained showing the dependence of the cleaning efficiency from suspended solids of the pH of wastewater. Relation of cleaning efficiency from coagulant dose was investigated at the second stage. The most kindly conditions of wastewater for coagulation and rational doses of coagulants were determined in results of this research for every type of wastewater. The obtained results make it possible to promptly correct the technological regime of the local treatment plant with quality changes of inlet flow.