DEVELOPMENT OF DESIGN CRITERIA FOR THE CHEMICAL PRECIPITATION PROCESS APPLIED IN CRACOW WASTE-WATER RECLAMATION SYSTEM

The results of investigation on coagulation as tertiary treatment of secondary effluent in the water reuse process for industrial application are presented. The investigations were carried out at the municipal wastewater plant in the city of Cracow. The experimental model has been operated continuously under dynamic flow conditions; the paper describes the construction of the model as well as the experiences gained during its operation. The investigations which were carried out in the laboratory batch tests are also described. The studies were conducted using alum, ferrous sulphate, lime, an alum combined with lime and ferrous sulphate combined with lime doses. The best effectiveness of orthophosphorous removal was found for alum /96.2 %/ and ferrous sulphate combined with lime /84.2 %/. The best results of permangante COD removal were reached for ferrous sulphate /52 %/ and ferrous sulphate combined with lime /51.3 %/. In the paper the suitability of experimental models and procedure for experimental data evaluation in development of design criteria are presented.