Guideline DWA-M 803E - Cost Structures in Wastewater Engineering - November 2006

The Advisory Leaflet provides the preconditions for the collection of investment costs and operating costs as well as any relevant technical information about the lifetime of the project in a standardized and constant form. In a first step (Advisory Leaflet version of 3/2002), a constant cost structure was developed which initially focussed on recording the investment costs alone. The structure comprises the population of all elements equivalent to a master structure.
In this present version (11/2006), based on the implemented containment of locations where information (costs, performances, etc.) may arise from individual projects, this information has been established in a next step, e. g. type of costs, technical documentation and performance indicators, that should be linked to the structural elements of the plant. The value and the unit can then be filed on the place that is identifiable through the location and information characteristic. Thus not only costs (investment, operation and annual costs) can be entered, it is also possible to calculate specific costs, performance indicators, etc., and finally the principles are established for the structure of a generally usable database on costs.
For this reason, it shall be expressly pointed out that the structural depths of the cost structure on hand must not be interpreted as an indirect recommendation for the required detailed description of particularities of the levies of costs. Different structural depths may be required or sufficient in dependence on the individual problem or tasks. The achievable benefit here is to be weighed against the growing expenditure on a case-to-case basis. The choice of how extensively particularities are described and reflected by the different hierarchic levels, is subject to the user. Therefore, the master structure can be taken as a basis for actions by the operators of plants of any dimension. It is intended to establish the DWA-Working Group WI-1.1 as an "information turn-table" for all activities in the realm of cost structures including a most actual up-dating in order to safeguard an orderly standardization and improvement of cost structures. Only because of this concentration will it be possible to permanently bundle and mutually and bindingly regulate unavoidable new and possibly controversial opinions and discussions on the background of a comprehensive know-how.