“…These measures usually account for 50% of the total costs of wastewater treatment. At the same time, they demand special and specialized guidance [ [4] , [5] , [6] , [7] ]. The most common methods of sludge disposal in the world include: direct discharge into the environment, such as discharge into rivers and channels near the drinking water treatment plant, taking into account environmental laws and guidelines, land application such as use as fertilizer in agriculture or restoring the forest and discharge to the sewage collection network which has recently received attention [ 8 , 9 ].…”