Acta Scientiarum Polonorum

This study aims to evaluate the performance of subsurface flow constructed wetland in Latvia which was established to receive storm water from surface runoff from a farmjard in agricultural area. As a part of this study, subsurface horizontal flow wetlands was monitored, in order to evaluate the changes in the efficiency of treatment depending on biological factors. The efficiency of horizontal subsurface flow constructed wetland was evaluated by comparing the concentration of total suspended solids (TSS), biochemical oxygen demand (BOD5) and chemical oxygen (COD) at inlet and outlet of the wetland depending on temperature and pH. Since June 2014, water quality monitoring in a research site in the farm “Mezaciruli”, Zaļenieku parish, Jelgava region has been carried out to treat the point source agricultural runoff from the impermeable pavements. The analysis of the data obtained in the monitoring allows to draw conclusions about the influence of certain factors in the subsurface flow constructed wetlands under the climate and environmental conditions in Latvia.