Options
1996
Book Article
Title
TECIS - ein Informations- und Beratungssystem für die dezentrale Abwasserentsorgung in ländlichen Gebieten
Abstract
In many rural regions, there is a lack of orderly sewage disposal. Due to the high building costs of sewers, a connection to central sewage plants is usually not defensible. In this case, a decentralized sewage disposal provides a economical solution. The planner of such a disposal has to find a favorable allocation structure of sewage plants and sewers as well as a favorable wastewater treatment technology for a specific plant location. These tasks both can not be solved separately since the chosen structure considerably influences the set of admissible technologies. The overall objective of this planning problem is the redevelopment of the sewage disposal in a rural region. This overall objective is determined by objectives like costs, purification performance, reliability and ecological criteria. These objectives are composed of subcriteria again. So, this planning problem can be formulated as a MCDM problem, where from a set of alternatives there has to be selected a best alternati ve. However, the set of alternatives is not specified a priori but has to be generated using several sources of information. The Technology Information and Consulting System for Decentralized Sewage Plants (TECIS) supports the planner solving this MCDM problem. The DSS TECIS consists of three main components: communication system, knowledge component and problem solver. It can be used in two modes. In the information mode the user can get, insert or change information's which are stored in the data base, knowledge base and model base. The consulting mode gives active support for solving the planner's MCDM problem. From the description of the places to be disposed and the potential locations for the sewage plants the set of feasible structures is generated. Each structure can consist of several substructures. (For instance, one of four villages to be disposed is connected to one sewage plant and the other three villages are disposed by a second plant. So, this particular structure cons i sts of two substructures.) For each substructure the feasible wastewater treatment technologies are chosen from the knowledge component and rated by a vector objective function. By combining the non-dominated alternatives of the substructures, the set of feasible alternatives for all structures of disposal is created. The non-dominated elements of this set are presented to the planner. There are four methods for selecting a best non-dominated alternative : relaxation method, reference point method, rank order method and priority method. By means of these methods the planner can choose a best structure of sewage disposal for the given region.