We are surrounded by water and consequently also wastewaters are a part of our everyday life. Before returning them to nature wastewaters must be treated to limit the pollution of surface waters. Municipal biological wastewater treatment plants are very effective for the treatment of municipal wastewaters, but many households and settlements cannot connect to the public sewage system and have to use small wastewater treatment plants, including constructed wetlands, which are increasingly used. Therefore, we wanted to evaluate their efficiency for treatment of municipal wastewaters.
In the master's thesis, we used a laboratory constructed wetland for treatment of model municipal wastewater. We focused on the removal of organic pollution, nitrogen and phosphorus compounds, and chloride from wastewater.
In the laboratory, we determined various parameters of wastewaters, namely concentrations of ammonium, nitrate, nitrite nitrogen, orthophosphate, chemical oxygen demand, biological oxygen demand, total organic carbon and chloride at the influent and effluent of the laboratory constructed wetland. The treatment efficiency of the system was determined from the values of the concentrations at the influent and effluent. We monitored the efficiency at two different flow rates. We found that the laboratory constructed wetland removed 91% of biochemical oxygen demand, 88% of chemical oxygen demand, 86% of the total organic carbon, 83% of nitrate nitrogen, 76% of orthophosphate and 92% of nitrite nitrogen (decrease in concentration only at lower flow). But concentrations of ammonium nitrogen and chloride did not decrease.
According to the measured parameters, the laboratory constructed wetland showed to be an efficient and reliable technology for treatment of municipal wastewater. Constructed wetlands are environmentally friendly technologies, they are efficient and do not require demanding equipment to operate.
|
