Another turn of energy and sludge audits was held in Latvia and Estonia on 8–11 May 2017. This time, the international IWAMA audit team consisted of eight students from universities in Estonia, Finland, Germany, and Sweden. The audit performed covered three plants of different size and capacity.
By now, the audit procedure has been already established, practiced and optimized during previous visits done in the IWAMA project. An average audit day starts with a brief introduction, followed by a common guided tour of the plant, during which the employees of the WWTPs provide the students with detailed information. After that, the team splits up in two, one focusing on sludge and the other – on energy issues. Both teams collect and process data for further calculations. While the sludge team gathers samples for further analyses, the energy audit team, accompanied by the WWTP representative, visits once more specific places related to the energy consumption of the plant. Plenty of notes and pictures taken of the engines and devices are later fed into tables. Audits are very systematic, detail-oriented and intensive, and the quality of information input is essential for these processes. Therefore, during the audits, the representatives of the plant are available to provide data and answers to many questions.
The first audit organized during the May week took place in Jurmala WWTP (PE 30 000) in Latvia. There, apart from the thorough audits performed, a measuring device was installed to meter the actual electricity consumption of one of the aeration units.
For the next investigations, the audit team went to Estonia to visit the plants of Tartu and Türi. In Tartu plant with PE 100 000, the team was introduced to some extra processes; thermal sludge hygienisation process and a membrane filter used for reducing the suspended solids from the effluent after the secondary clarifier. In Türi, the team got acquainted with the investment piloted in the IWAMA framework, dealing with removing heavy metals from the sludge through humification in fields.
Thanks to a good spirit of the auditing team and enthusiastic, friendly and supportive representatives of the hosting WWTPs, the audits were successfully executed.
The next WWTP to be visited by the IWAMA auditing team is Grevesmühlen, Germany on 5–6 June 2017.