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Weltec Biopower upgrades municipal wastewater treatment plant in Germany

Technical operator SudWasser has commissioned the biogas plant manufacturer Weltec Biopower as the general contractor for the setup of an anaerobic digestion unit and the utilisation of sewage gas at a wastewater plant in Burgebrach in Bavaria, Germany.

The collected gas will be used for the generation of energy in the combined heat and power (CHP) plant for the existing wastewater treatment plant, which serves a population equivalent of 13,000.

In addition to the aerobic treatment stage, the organic material will be subjected to anaerobic treatment starting from April. 

To ensure optimum treatment of the daily influx of 16m3 of raw sludge with a dry matter content of 4 to 4.5%, a specially designed V4A stainless-steel digester has been installed.

In it, a diagonally installed long-axis agitator will mix the sludge in order to gently carefully promote the microbiological transformation to methane.

With its capacity of 420m3 and a flexible gas storage roof with a storage volume of up to 68m3, the bioreactor is large enough to run the CHP plant with its electrical output of 28kW and thermal output of 58kW without any interruptions.

The generated power will be used directly at the facilities, and the heat will be employed both for speeding up the digestion process and for use at the sewage treatment plant site. 

Apart from energy generation and sludge stabilisation, the minimisation of odour emissions was another decisive factor in favour of the Weltec anaerobic stage.

Through the systematic anaerobic sludge stabilisation, unpleasant odours – which constantly plagued Burgebrach – will henceforth be largely prevented.

“In the sewage treatment plant in Burgebrach, we used to stabilise the sludge without using the digestion gas. Through the installation of the digestion unit, we have established a sustainable, climate friendly energy concept and can reduce the amount of sludge. In total, the COD load in the wastewater will be reduced by about a third,” said Arne Nath, head of the wastewater department of the operator SudWasser.

However, the plant upgrade also delivers financial advantages, as the said benefits and a bonus under the German Combined Heat and Power Act (KWKG) will result in a yearly cost advantage in the medium five-digit range.

“Our customers appreciate our anaerobic sludge digestion for its economic and ecological sustainability. It produces energy, cuts disposal costs, and generates municipal income. Moreover, the plant capacity can be expanded without any major need for additional space,” said Jens Flerlage of Weltec Biopower, summarising the system‘s benefits.

“These positive aspects make this smart alliance of wastewater treatment and energy generation basically viable for all sewage treatment plants for population sizes of 8,000 to 50,000,“ Flerlage said.