Contamination of the Root Vegetables Wash Water and its Treatment Efficiency

Abstract

Growing volume of washed vegetables in Europe and Lithuania means that more drinking water is consumed and more wastewater is produced. Farmers, who engage in washing vegetables, face the problems of wastewater treatment, wastewater storage and utilization. Wastewater released to the environment from their farms would meet hygiene and environmental protection criteria. In this article the contamination of wastewater, produced by washed root vegetables, in four large Lithuanian farms was measured according to suspended solids (SS), BOD, COD, total nitrogen and total phosphorus. Contamination of the wash water and wastewater was evaluated comparing the mean values with legislative limit values and with typical sewage contamination values. In all farms wastewater of initial root vegetables washing was treated in settling basins. Wastewater of one carrots washing farm was treated in the natural wastewater treatment system of constructed wetland and two biological ponds. Wastewater treatment efficiency according to various pollution parameters was calculated. The result shows, that the natural wastewater treatment system with constructed wetland and biological ponds is suitable for farms, that wash and produce vegetables, but before releasing wastewater to the environment, it has to be settled.