Reduction of Environmental Pollution Applying Decentralised Wastewater Treatment Systems in Small Communities

Abstract

Small size wastewater treatment plants are widely used as a decentralised treatment solution in regions, where the access to the sewer system is not available or the connection to an existing system is not economically sound like in small communities (e.g. schools, hospitals, army camps, etc.). The local treatment of wastewater can be performed by small size units applying activated sludge or attached growth biomass. In this paper the performance and operation of a process unit applying conventional activated sludge is analysed. For this purpose, a simulation tool with mass balance modelling was used. In the model, various influent wastewater qualities were set in order to examine their effect on each process. Operational parameters were fine-tuned to increase the capacity by utilising additional aeration. As a result, it can be stated that the nominal capacity of the treatment unit is overestimated; in the Central European region, due to the wastewater characteristics, the examined treatment unit could handle 40% of the nominal capacity.