The use of wastewater and sewage sludge is regulated by the Waste Act (Journal of Laws 2019, item 701) and two regulations of the Minister of the Environment (Journal of Laws 2019, item 1311) and (Journal of Laws 2015, item 257).
Wastewater and sewage sludge are available from sewage treatment plants – their use in agriculture is possible in untreated form and after treatment, which involves composting. Composted sewage sludge can be given the status of a ‘soil improver’ if it meets the requirements of the registration process and is authorised. In any other situation, treated (composted) sewage and sewage sludge must be subjected to compositional analysis, just like the untreated product. Testing of sewage sludge includes determination of pH, dry matter, organic matter, total nitrogen, ammonia, total phosphorus, calcium and magnesium, heavy metals, presence and quantity of pathogenic bacteria and intestinal parasite eggs. Sludge testing documents must be kept for a period of 5 years.
Restrictions on the use of municipal sewage sludge arise from requirements concerning its composition and when and where it may be used. Municipal sewage sludge may only be handed over to the landowner by the sludge producer. Municipal sewage sludge that meets sanitary requirements for the presence of Salmonella bacteria and eggs of the intestinal parasites Ascaris sp., Trichuris sp., Toxocara sp. and chemical requirements for heavy metals may be used for agricultural applications. It is the responsibility of the operator offering such sludge to meet these requirements. The field on which the sludge is to be applied must meet the requirements for acceptable amounts of heavy metals already present in the topsoil (0-25 cm), and the pH of this soil must not be lower than 5.6. The sludge may be applied if it is stabilised and properly prepared for application. They must not cause deterioration in the quality of the soil and the quality of surface and groundwater. They may only be applied outside the growing season of plants intended for direct human consumption. They may not be applied closer than 50 m from surface water courses and reservoirs and closer than 100 m from water intakes and dwellings, on floodplains and wetlands, temporarily frozen, highly permeable areas (sands) when ground water is shallower than 1.5 m, on sites with a slope exceeding 10%, in vegetable and fruit crops (except trees), on pastures and under shelter. Municipal sewage sludge shall be applied in liquid, slurry or earthen form. The application rate of sewage sludge or sludge shall be determined separately for each batch tested, taking into account good agricultural practice, other fertilisers, plant aids or soil improvers used on the land. A condition for the application of municipal sewage sludge in liquid form is that it is injected or sprayed into the soil, including hydroseeding (a biological method of land reclamation, steep heaps consisting of hydro-mechanically covering the surface with a preparation that is a mixture composed of water, plant seeds, cellulose hydromulch (cellulose fibres), fertilisers and substances protecting against water erosion, wind erosion and excessive drying). A prerequisite for the application of municipal sewage sludge in a smeary and earthy form is its uniform distribution on the soil surface. Municipal sewage sludge applied in all forms shall be mixed with the soil immediately after transport to the area where it is to be applied. A suitable fertilisation plan should be drawn up for the land on which the sludge is to be applied.
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