Cambi converts Beijing’s sewage sludge to clean energy and organic fertiliser

Cambi’s award-winning process, thermal hydrolysis (CambiTHP®), is patented and sold worldwide. Sewage sludge is pre-treated at high temperature and pressure (approx. 160℃), before it undergoes anaerobic digestion and becomes biogas and high-quality biosolids that can be used directly as organic fertiliser.

The process produces much more biogas than conventional solutions and reduces greenhouse gas emissions through the controlled use of biogas (methane) as renewable energy, less sludge transportation and replacement of conventional fertiliser. The Cambi plants in Beijing reduce greenhouse gas emissions with equivalent of removing 125,000 from the roads, or 300,000 tons of CO2 equivalent. The resulting Class A biosolids are used in agriculture, urban green spaces or, like in Beijing’s case, reforestation projects.

In this way, Cambi’s technology improves the urban environment in Beijing and helps China meet its renewable energy and climate change goals. In conjunction with the World Water Day (22 March 2017), with wastewater as main theme, thermal hydrolysis was promoted by the World Resources Institute as a model for resource reuse in the water sector, introducing an economic and sustainable approach to the water-energy-agriculture nexus.

Projects like this are at the heart of the global green transformation. Cambi’s plants in Beijing, developed in collaboration with the Beijing Drainage Group, are also a good example of how environmental technology can take over an increasingly important role in Norwegian exports. Green technologies are a priority for Norway, as industries strive to become greener, smarter and more innovative.

Cambi’s technology treats sludge from almost 60 million people worldwide, in Beijing and other major cities from more than twenty countries, including London, Washington DC, Brussels, Singapore, and Santiago de Chile. The technology is modular and has been implemented also for smaller cities, such as Hamar, Lillehammer, Stavanger and Drammen in Norway, and Tarnow in Poland.

In Oslo, the biogas recovered from Cambi’s organic waste treatment plant is upgraded to natural gas quality (bio-methane) and used to fuel garbage trucks and Oslo’s buses. This improves local air quality and reduces global greenhouse gas emissions. In other projects, the biogas is mainly used to produce renewable electricity and heat for the Cambi process. Cambi has 150 employees throughout the world, including 70 in Norway and 10 in China. The company has offices also in the UK, USA, Germany, Spain, Denmark and Singapore.

Cambi was established in 1989 by Glommen Skogeierforening. The company's name comes from the Latin word "cambium", which is the part of the tree where growth takes place. The technology developed by Cambi was initially used in the pulp and paper industry. Cambi’s first project within wastewater treatment was commissioned in Hamar in 1996.