There are two types of wastewater cleaning, separated by natural or artificial cleaning conditions. Under natural conditions, the decomposition of waste occurs in reservoirs and soil. If the number of organic substances is not enough, then the soil and ponds will cope with their work, but if there is too much organics, then the process of decay will begin, and the cleansing ability will decrease. You can make the decomposition process more intense using filtration fields and ponds.
