Compost Leachate Pretreatment by Coagulation/Flocculation Followed by Filter Press

Abstract

Compost leachate was treated with coagulation/flocculation followed by filtration in order to obtain effluent suitable for further purification by reverse osmosis process. The poly aluminium chloride coagulant and the poly acryl amide flocculant were ap - plied for coagulation/flocculation process. Filtration tests were performed to choose the proper fabric for filtration of compost leachate. There were huge differences between compost leachate samples’ properties taken at the plant; therefore, it was difficult to determine the optimum coagulant/flocculant dosage. It was found that, among the fabrics available, only one was appropriate, and was made of polypropylene. With other filter fabrics the pressure during the filtration increased above 6 bar, which means above the highest specified allowed pressure for the device used. The filtration was carried out with several differently pretreated samples of compost leachate. The turbidity was reduced by as much as 89.8 %. The particle-size distribution analyses showed that most colloids and suspended solids were removed after the treatment. The results indicate that combination of coagulation/flocculation followed by filtration is not adequate for proper treatment of compost leachate, and some other technique, such as electrocoagulation, ultrafiltration, and nanofiltration need to be investigated.