The Norwegian hi-tech company CAMBI has signed the contract to build a large Thermal Hydrolysis Process plant, for the Blue Plains Advanced Wastewater Treatment Plant in Washington DC.
Located at the District of Columbia Sewer & Water Authority’s (DC Water), it will be the world's largest Cambi Thermal Hydrolysis Process plant to date.
The Cambi process will produce biogas and high quality Class A biosolids fertilizer product, all to be built over a minimum area, saving on both investment and operational costs compared to conventional digestion.
The biogas will produce green electricity for the plant; reducing its carbon footprint significantly.
”This is the single largest contribution so far to greenhouse gas reduction in Washington DC,” said Mr. George S. Hawkins, General Manager of DC Water. The major contract forming part of DC Water’s $400 million (USD) biosolids management program was signed as a Joint Venture between CDM and PC Construction.
This design-build contract includes thickening, pre-dewatering, four trains of the Cambi thermal hydrolysis process, and four digesters. In addition, a 14 MW biogas CHP powerplant contract is
soon to be awarded, as well as a post dewatering facility contract. Mr. Hawkins adds that he is happy that DC Water has decided to be the first to implement the Cambi process in the United States and he thinks other cities will follow soon. ”This is the future of biosolids management because it is a sound solution for the environment. But the beauty of it all is that we are investing significantly less than we would for conventional digestion, and this choice will, in addition, save us some 20 million dollars in operational costs every year over many years to come.”
The plant will reduce DC Water’s carbon footprint by approximately 60,000 tonnes of CO2 per year. This will be achieved mainly through the generation of green energy, elimination of lime for stabilization, and reduced truck use for solids disposal and transportation. ‘For Norwegian based Cambi, this is a breakthrough on the US market,’ says Cambi’s CTO Merete Norli. ‘We have over several years worked with DC Water to achieve this. In the mean time we have had a great success in other countries and have built about 25 plants."
The THP plant for DC Water will have a capacity for some 400 tonnes of dry solids per day, which will make it the largest THP plant in the world and some 25% larger than the Manchester (England) plant which has just been completed.