Material Flow Analysis and Life Cycle Costing for Water and Sludge Processing for Case Study of a Small Wastewater Treatment Plant in Poland

Abstract

The primary objective of this thesis has been to contribute to the understanding of the total process of water and sludge handling of small wastewater treatment plants (WWTPs) within the framework of sustainable performance and optimum processing costs. This was done by conducting a case study on a WWTP in Poland. Substantial growth in the field of wastewater management is expected in the East and Central Europe. This is in particular true for the countries that recently became part of the EU and therefore are obligated to follow the many Directives that exists, including those concerning wastewater treatment. Consequently, Poland is expected to invest substantial amounts of money into their wastew- ater sector in the upcoming years. With over 15 million people living in the rural areas and majority of them still lacking access to proper wastewater infrastructure, the importance of small-scale WWTPs be- comes transparent.Four different configurations of technological solutions were evaluated for an existing small-scale plant in Poland. The benefits and disadvantages of combined treatment of raw influent and surplus sludge using fine screening and different solutions for end-of-line sludge treatment were assessed using Material Flow Analysis and Life Cycle Costing. The end use of the sludge was integrated into the Life Cy- cle Costing and tested for the alternatives of landfilling and incineration. The entire evaluation was done within the constrains set by laws and regulations.Combined treatment of raw influent and surplus sludge result in significantly larger concentrations of total suspended solids in the effluent and is not complying with the requirements set by the authority. Analysis of the economic feasibility show that composting as end-of-line sludge treatment is not benefi- cial for small-scale WWTPs. On the contrary, a significant cost reduction is achieved by direct utilisation of dried or dewatered sludge. Landfilling is not a preferred method from an environmental point of view, nor the best solution from an economic point of view for sludge management. Incineration of sludge to produce energy is both sustainable and economically feasible for small-scale WWTPs.The analysis shows the importance of choosing the right combination of technologies to comply with the requirements in effluent and to utilise the potential of saving notable amounts of money. A holistic approach taking into account the economic, technical, environmental and socials aspects is necessary to find the most sustainable solution.