Rūgštinio kazeino gamybos nuotekų dumblo panaudojimas maistinių augalų tręšimui

Abstract

The sewage of dairy products companies are very polluted by organic substances. The pH acidity of sewage varies between 5,5–7,6. The BOD of sewage of acid casein production is 25 000–35 000 mg O2/l, pH < 4.5. Amounts of heavy metals (zinc, cooper, lead and nickel) in sludge of sewage cleaning systems do not exceed permis-sible pollution standards. The sludge might be used for fertilization without any limits. The sludge contains a lot of nitrogen, magnesium and phosphorus, but it lack of potassium and calcium. Results of the experiment showed that the sludge of sewage of production of acid casein is suitable for fertilization of salad and cress. The viability of salad and cress and the biomass of these nutri-tional plants increased using this sludge as a fertilizer. It was found that the most useful mixture of soil and sludge proportion for fertili-zing is: 1:1 for salad; 3:1 for cress. The parameters of fertility of nu-tritional plants increased when potassium sulphate was added into the mixture of soil and sludge.