Research into processes of wastewater treatment at plants of meat processing industry by flotation and coagulation

Abstract

The aim of present research was to select the rational method of purification of highly concentrated wastewater of meat processing enterprises. For this purpose, the optimal parameters of flotation and reagent treatment were determined. The study was conducted with two types of wastewaters. The first was formed within a week during washing meat and the equipment. Another, more concentrated and highly alkaline, was formed once a week during washing meatsmoking facilities. Less polluted wastewater should be cleaned by flotation, followed by the reagent deposition. Flotation within 1.5...2 hours eliminates almost half of the chemical consumption of oxygen. By the reagent method, using hydrated calcium oxide, previously activated by ultrasound, and the coagulant sulfate FeSO4, we achieved a decrease in the CCO practically to standard indicators. For the purification of more concentrated wastewater with high alkalinity, only reagent treatment is required, because of very intense foaming and carrying out the liquid phase (50...70 %) during flotation. Calcium hydroxide, activated by acoustic oscillations of ultrasonic range, should be used as reagents and iron (II) sulfate should be used as a coagulant. Based on the performed studies, the technology of wastewater treatment at meat processing enterprises with incomplete production cycle was proposed. It covers the following main stages: wastewater neutralizing, preliminary rough treatment on the bulk filter, stage-by-stage reagent treatment, filtering, and decontamination.