A nature-based wastewater treatment in Nevřeň

Most small municipalities consider various alternatives for sewage and rainwater disposal in their territory. The municipality of Nevřeň has taken an unconventional path in wastewater treatment and polishing. The municipality decided for mechanical pre-treatment followed by a system of two biological ponds (tertiary water treatment) - an economically viable solution in terms of implementation and operation for the polishing of water flowing in from the existing combined sewer system before it discharges into the Třemošná stream. The combined sewer system receives overflows from septic tanks and domestic wastewater treatment plants in private properties. A wastewater treatment system using a set of biological ponds (if the geomorphology of the locality allows it) is an opportunity for a small village to discharge clean water into a watercourse with relatively low construction costs, in addition to reasonable maintenance costs for the entire WWTP system and, therefore, with minimal sewer charges for the residents. It assumes co-responsibility and involvement of the residents in the process of cleaning their own sewage, but it eliminates the risk associated with possible errors in the operation of small domestic wastewater treatment plants. It also includes an Imhoff tank (with a slot for sludge), capable of containing accidental oil spills, e.g. from a car accident on a drained road, using scum boards. The system of ponds is a distinctive landscape-forming element that, at first glance, does not resemble a municipal wastewater treatment plant. The entire system, including the riparian greenery, is able to retain water in the landscape and improves the overall environment in the village and improves the water quality in the Třemošná stream.