Dražovice reed beds and stabilisation pond wastewater treatment system: long-term operation and monitoring results

The aim of the paper is to present results of the ten years long monitoring of the treatment processes, efficiency and operation of a wastewater treatment plant combined mechanical pre-treatment, horizontal sub-surface flow reed beds and stabilisation pond as a final purification equipment. The treatment system was built in the Dražovice village (the Czech Republic, South Moravia Region) for 800 population equivalent (P.E.) in 1999. The constructed wetlands with horizontal sub-surface continual flow reed beds, as a main biological step of wastewater treatment, has been built and operated in the Czech Republic since 1990. In case of sources over 500 P.E., there is the legislative requirement for ammonia nitrogen sufficient removal in the Czech Republic. The monitored system represents a category of sources between 500 and 2000 P.E. with the higher treatment efficiency requirements. The plant has been monitored in detail since the start of operation in 1999. A detailed monitoring programme includes: wastewater flow measurement, water temperature and oxygen regime measurement, organic and nutrient pollution removal rate assessment, hydraulic characteristics of the reed bedś filtration medium. Results of the survey include treatment efficiency calculation, hydraulic and mass load assessment. The differences in the achieved efficiency are compared between vegetation and non-vegetation periods.