Because of their geographical and physical impact, supply and disposal projects must stand in a clear and plausible relationship with other environmental and geographical areas. This is particularly true of wastewater disposal (WWD) projects, bearing in mind the potential danger posed by the domestic, commercial and industrial wastewater to be disposed of.

Areas which may be affected by WWD projects, such that this may lead to conflicts of use and interactive effects include, in particular, the following:

• bodies of water (surface water, groundwater); water resources management, hydraulic engineering

• soil; agriculture and forestry

• air

• water production, water supply

• waste management, waste disposal

• nature conservation, countryside preservation, recreational resources

• urban/community planning, industrial development

• monuments and heritage

• traffic planning (roads, railways, waterways, flight paths)

• existing/future regional planning, land-use and development planning; activity planning

• distance problems in existing and planned residential areas

• availability of land and soil.

If conflicts of use occur, the options must be weighed up. The standard against which these are judged is not the status quo, i.e. the structures and services existing prior to execution of the wastewater disposal project, but rather the development potential of the area in question. The criterion is thus the capacity and not the present performance (39). This approach also stresses the importance of identifying and assessing the soil potential, the biotope potentials and the hydrogeological potentials (in terms of both quantity and quality). Adjustment, alleviation and compensatory measures may provide crucial help in arriving at the environmentally ideal overall solution.