ACTIVATED SLUDGE TECHNOLOGY COMBINED WITH HYDROPONIC LAGOON AS A TECHNOLOGY SUITABLE FOR TREATMENT OF WASTEWATER DELIVERED BY SLURRY TANKS

摘要

The paper presents information related to the use of hydrophytic technology combined with traditional activated sludge solution for wastewater treatment in areas without central sewage system. The analyzed wastewater treatment plant (WWTP) was operated in activated sludge technology with hybrid activated sludge reactor where biomass is kept in settled and suspended form. Treatment system was completed with hydroponic lagoon. Hydroponic lagoon has been used as tertiary treatment, in which the self-cleaning processes with the participation of the plant has come to an additional reduction of nutrients. Analyzed three stage treatment plant is located in the municipality of Nowa Sól. Only domestic wastewater delivered by slurry tanks are treated there in amount of 60 m3/d. During the observation high average concentrations of total nitrogen (201.0 mgN/dm3) was observed and organic matter expressed by COD reaching 1341.5 mgO₂/dm3 and BOD5 on the level of 246.3 mgO₂/dm3 were noted. A characteristic feature of an object designed for wastewater treatment delivered by slurry tanks is high irregularity of wastewater supply and high instantaneous loads of pollutants (the system does not provide expansion tank). The biggest inequality factor of the flow to the reactor was observed in December 2014 (N_d=3.9). During the observations also occurred days with no inflow of sewage. The study shows the dynamics of changes in the amount of delivered domestic wastewater and sewage flowing out of treatment plant including inequality factor. Information about quality of wastewater was used to determine the reduction of concentrations of pollutants like organic matter, suspended solids, nitrogen and phosphorus.