Water Analyses, Eco-Balance and Socio-Demographic Analyses as Prerequisites for Solutions of the Sewage Treatment Problems in Rural Areas

摘要

The implementation of theEU-water framework directive (EU-WFD) demands a financeable and adaptablesewage treatment, creating a need for action especially in rural areas, wherethe “good ecological status” is often not reached even though the sewage worksfulfill the legal minimum requirements. Therefore the construction of new, moreefficient wastewater treatment plants is advisable. Due to the precariousfinancial situation in most rural areas, many municipalities can however notmaster the necessary funds for an improved waste water infrastructure. A largepart of the costs would have to be shouldered by the local population in theform of additional sewage levies, leading to massive socio-economic strain.Hence, different solutions, which are tailored to the socio-economic,demographic and environmental characteristics of rural areas and fulfill thelegal requirements, need to be developed. One possible approach is presented inthe form of the Dirlammen case study (municipality Lautertal, Hesse, Germany).It consists of 1) biological and physicochemical analyses of the waste waters,2) a modified eco-balance for the construction of a new sewage works and 3)socio-economic and demographic analyses of the population. It serves as a toolfor the assessment of the influencing ecological, socio-economic anddemographic factors on the sewage problems in rural areas. These findings caneasily be transferred to other rural areas with a similar configuration andthus deliver the basis for a generally applicable approach to these problems.The results of the comprehensive analysis have shown for the municipality Dirlammen/Lautertalthat the continued operation of the existing pond sewage plant is, with regardsto the ecological, socio-economic and demographic points of view, preferable tothe construction of a new waste water treatment plant. With regard to thesustainability principles of the sewage treatment and the objectives of theEU-WFD, existing sewage works should be operated for as long as the sewagetreatment is feasible within technical and legal boundaries. With theconstruction of new facilities on the other hand, the expected improvement ofthe water quality has to be weighed against the ecological impairments causedby the construction itself. Rural waste water plans have to be developed forthe long-term, taking not only the ecology into account but also the demographicchange. Possible approaches in this regard could be a shift towards adecentralized waste water treatment concept and–even more important–improvementsof the river morphology. But also the reduction of the diffuse pollution fromagricultural sources should be considered for the development of strategies forthe improvement of the ecological state. Short-term optimization measures inthe existing sewage works might also improve the water quality until thelong-term development plans can be implemented. In particular the challenges ofthe demographic change and linked with that the changing requirements for therural waste water treatment must be addressed by any future plans. Only withthe help of such a comprehensive approach the dangers of bad planning andunacceptable socio-economic burdens can be minimized.