DIN 4261-1:2025-12

This document specifies requirements for systems with up to 50 PT for the pretreatment of domestic wastewater obtained by the separation method from one or more buildings or properties, including wastewater from commercial or agricultural operations where the inflow corresponds to domestic wastewater in terms of quantity and composition. These systems alone are not suitable for the treatment of domestic wastewater. This document does not apply to aerated pretreatment systems. This document does not apply to the treatment or co-treatment of: - commercial or agricultural wastewater, insofar as it is not comparable to domestic wastewater; - condensate from fireplaces with pH values below 6,5; - extraneous water (for example, drainage water); - cooling water; - contents of chemical toilets; - swimming pool effluent; - rainwater. This document specifies, in particular, sizing requirements for systems and conditions for the installation, operation, and maintenance of pretreatment systems. This document has been prepared by Standards Committee Water Practice, Working Committee NA 19-05-04 AA "Kleinkläranlagen" ("Small sewage treatment plants").