| Abstract [eng] |
The meat processing industry uses 24 % of the total freshwater consumed by the food and beverage industry, with the beverage industry in particular consuming 13 % and dairy industry 12 % of freshwater. Only a few percent of consumed water is a component of the final product, the remaining part is wastewater. The main characteristics of it are: high biological and chemical oxygen demand, high fat content and high concentrations of dry residue, sedimentary and total suspended matter as well as nitrogen and phosphorus. It may also contain disease microorganisms, eggs of ascaris and intestinal parasites. Traditionally biological treatment methods are used for the treatment of meat processing wastewater. Although biological treatment can achieve high efficiencies of organic matter and nutrient removal, the treated water needs further treatment in order to be reused. Therefore, advanced oxidation processes are becoming an alternative to conventional treatment and a complimentary treatment option, as either pre – treatment or post – treatment, to current biological processes. The goal of this thesis – to evaluate the effectiveness of meat processing wastewater treatment using combined biological and advanced oxidation processes. To evaluate the effectiveness of wastewater treatment using combined biological and advanced oxidation processes the experiment was carried out. First, the meat processing wastewater was treated in biological reactor then in the dielectric barrier discharge (DBD) reactor. The wastewater used in the experiment was taken from „Klaipedos mesine“. The experiment was focused on the determination of the optimum retention time of the wastewater in biological reactor as well as in the DBD reactor. The retention time was being changed within the range of 0,5 – 6 hours in biological reactor and 2 – 30 minutes in the DBD reactor. The effectiveness of wastewater treatment was evaluated according to total organic carbon (TOC) concentration in the treated water. The results showed that the effectiveness of wastewater treatment increases when the retention time in both biological and DBD reactors icreases. It was concluded that the optimum retention time of the wastewater in biological reactor is 280 minutes and in DBD reactor – 30 minutes, the effectiveness of wastewater treatment obtained under mentioned conditions was 65,6 %. The microbiological tests showed that after treatment of wastewater in DBD reactor the microbiological pollution was eliminated. Also, it was noticed that the slight yellow colour and the odor of wastewater disappeared. It was concluded that wastewater treatment using combined biological and advanced oxidation processes in „Klaipedos mesine“ would be useful due to possibility of water reuse. About 50 % (13 700 m3 annually) of treated water could be reused for cleaning of premises and transport. The volumes of biological reactor and DBD reactor were calculated according to wastewater flow rate, the calculated volumes are 14,6 m3 and 1,6 m3 for biological and DBD reactor respectively. Also the electricity consumption for the treatment of wastewater in DBD reactor was calculated, for 1 m3 of wastewater 8,8 kWh of electricity energy is consumed. |
