The student audits performed in the framework of the IWAMA project aim at exploring the current state of several wastewater treatment plants in terms of the efficiency of their energy and sludge management. While in the project we focus on improving the resource efficiency of the wastewater management field in the Baltic Sea Region, it is important to reach said efficiency on the local level.
The plants where the audits had been implemented are the project partners of IWAMA. Last week, we held the last audit of the series: it took place on 6 June 2017 in Grevesmühlen, Germany.
The WWTP Grevesmühlen is a very specific case for the current audit process. While other plants visited by the student audit group have either only started to implement investments planned in IWAMA, or have those as pilot systems not yet integrated into the main process, the facilities in Grevesmühlen have already been under the renovation for some time. The facilities are being expanded to cover a larger territory, from 40 000 to 65 000 PE. This WWTP also has a particular characteristic influencing the treatment process: approximately 60% of the flow comes from the industrial source (creamery and coffee grounds industry that significantly affect the state of the sludge). With sludge being used in agriculture, it is important to maintain its quality. Further, from the energy point of view, the Grevesmühlen facilities are self-sufficient in the biogas production, and they even sell some amount of treated water for heating of the nearby shrimp farm.
For the student audit group, it was very interesting to visit the Grevesmühlen plant and follow the process gathering information on energy consumption and collecting sludge samples for further analysis. However, a challenge was encountered straight from the beginning, as in the middle of the renovation process, there is data available for very different systems. The audit team collected measures both for years 2016 and 2017, and it is now only a matter of careful evaluation to process the data to create a model as much up-to-date as possible.
Now, with all the data sheets filled with information, the team continues to evaluate the performance of the plants, and, when necessary, contacts the plants' representatives for more precise numbers. The first results of the sludge sample analysis were presented during the audit meeting that followed on 9 June 2017 in the Technical University of Berlin. Otherwise, for most of the time the student audit group works locally, based in their own universities (in Tartu, Berlin, Lahti and Kalmar), and the costant exchange and update of information is done online.