In contrast to the familiar helophyte filters and the Dutch 'waterharmonica' (a system which fills the gap between treated waste water and surface water), biocascade water purification is being developed into a regenerative system, as part of which efforts are made to ensure the availability of nutrients in the future and also to prevent the accumulation of nutrients. To achieve this, initial research is being carried out into system parameters in areas such as water quality, soil composition, potential interventions in the hydrological cycle and the presence of aquatic plants in the area. Dependent on the demand for purification, customised biocascade water purification systems are currently being produced which cleverly use soil processes during 'wetting' and 'drying out' and employ aquatic plants as bioengineers. Alongside surface water purification, biocascade water purification can be developed for use in post-purification of process water from industry or for post-purification of effluents from waste water purification processes. Systems that are burdened with relatively heavy nutrient loads provide opportunity to specialise the water purification for the production of biomass. This biomass can then be directed to various biobased industries in order to produce biogas or other products.