EFFICACY SURVEY OF SOME SEWAGE-TREATMENT PLANT-SYSTEMS ON PIG FARMS IN SLOVAKIA

Bacteriological, helminthological and physico-chemical examinations we re carried out to investigate the technological procedure in three wat er treatment plants treating slurry from large-capacity pig farms (Kos icka Polianka, Spisske Vlachy, Velky Dur). Our investigations were foc used on the testing of effectiveness of mechanical, chemical and biolo gical treatment system most frequently used in Slovakia. Our investiga tions revealed that water-treatment plants, operating on pig farms, fu lfil only the supplies management requirements concerning the treated water, discharged into the recipient. From the hygienic viewpoint furt her processing or utilization of the solid fraction remains unsolved. This fraction contains considerable concentrations of bacteria and par asitic germs (Ascaris suum, Trichuris suis, Isospora sp., Eimeria sp.) most of which exhibit high tenacity in the environment. It is recomme nded to process this solid fraction by composting before it is applied as a manure. However, the measured values did not exceed the referenc e hygienic limits. The technological stage of chemical treatment, whic h follows after the separation and utilizes some coagulants (aluminium sulphate, ferrous sulphate), can increase the chemical load of water stripped of crude organic pollutants, by some undesirable chemical ele ments.