Cambi Awarded Contract in Växjö

Cambi AS (Norway) has been awarded the thermal hydrolysis contract for upgrading the biogas plant at Sundet wastewater treatment plant in Växjö, Sweden. Växjö is located in southern Sweden and is regarded as one of the “greenest” cities in Europe. The city has more than 61 000 inhabitants.

This is Cambi’s first contract in Sweden and a breakthrough in the Swedish market. Cambi are pleased to see that Växjö is the first city in Sweden to adopt their technology based on its unique thermal hydrolysis processes (THP), says Mikael Runeson who is Cambi’s representative in Sweden. He confirms that Sweden is a large potential market for THP.

The new THP-unit in Växjö will start producing biogas in July 2014, and the production of biogas will be 20 % higher than conventional technology. All the biogas will be upgraded to vehicle gas and used in the transport sector, Runeson states. Reducing CO₂ emissions in the transport sector is regarded as a high priority in Växjö which started its “green journey” two decades ago.

The THP-unit consists of pre-dewatering equipment, Cambi THP, heat exchanger and steam boiler. All rebuilding of the existing plant and integration into the existing operation system is also included in Cambi’s contract. The steam boiler will be fueled with wood pellets. Therefore the whole process will run on renewable energy. The resulting biosolids will be used as a REVAQ-certified fertiliser in agriculture.

The municipality of Växjö has recently started operating a pre-treatment plant for source-separated household food waste. The aim is to increase the capacity of the existing biogas plant to produce biogas also from food waste with co-digestion. In 2030 the new plant will treat 8 600 metric tons of dry matter annually according to existing plans, of which 60% is sludge and 40% is food waste, Mikael Runeson explains.