The use of constructed wetlands is one of the most progressive approaches for wastewater treatment. Even in ancient times, people knew that dirty water, passing through swamps, comes out clean. Constructed wetlands systems are a specially designed swamp ecosystem that imitates natural models, in which, due to a combination of physical, chemical and biological processes, the incoming water is purified from organic and inorganic impurities in such a way that the water leaving from there meets the necessary parameters.
What is an constructed wetlands? Usually this is a pool filled with a biologically active substrate (gravel, sand, etc.), through which water flows that has been purified. In the substrate (as a rule) grow aquatic or moisture-loving plants that perform an important function of maintaining the necessary conditions in the ecosystem. However, the main role in the process of water purification is played not so much by plants as by various microorganisms living in the substrate and root biomass of plants. Compared to other practiced wastewater treatment methods, swamps benefit primarily from lower operating costs, greater reliability, simplicity, as well as the attractive appearance that the plants growing in them create. Constructed wetlands can operate without the use of electricity, and usually do not have complex and expensive technical components that can fail. Caring for them is not difficult. They can operate in intermittent and seasonal modes, with alternating periods of idle and load, which can be a problem for other types of autonomous sewer systems. They can work in winter under a layer of ice and snow. And, finally, they serve as a decoration of the site, being an element of landscape design [1].
In any case, once the owner of a HoReCa complex decides to build a wastewater treatment system, he/she needs to explore the available technical options. The following examples from the practice of Kyrgyzstan will help complete the picture.