The first full-scale plant for sludge disintegration through Cambi thermal hydrolysis was started up in Hamar, Norway at the end of 1995. It is the first plant with a new design where sludge is directly heated by live steam. During the last three years the plant worked with an availability of over 99%. Prior to hydrolysis the sludge is dewatered and the digester is fed with 10-12% DS, saving more than 50% of digester volume compared with a conventional process. The degree of stabilization is around 60% measured as rate COD-conversion into biogas. The stabilised sludge, which is guaranteed free of pathogens, is an attractive product to agriculture and has a high fertilizing effect.

Dublin's Ringsend WWTP was designed to serve a population of approximately 1.2 million p.e. with a sludge production of 37,000 dry tonnes per year after upgrading to full secondary treatment. Several technical solutions were put forward as part of a design, build, finance and operate (DBFO) competition, with the chosen solution being a proposal by Black and Veatch for a combination of sequencing batch reactor (SBR) technology and anaerobic digestion with Cambi thermal hydrolysis pre-treatment (THP). The THP plant was built by Cambi and handed over to B&V in 2002. The plant is now operated by Celtic Anglian Water. In September 2004 a test was carried out on the mass and energy balance of the plant following 2 years of operation and is detailed in this paper. The process enables digestion at very high dry solids feed and low hydraulic retention time. The plant was built with three digesters of 4250 m3 each and is fed with hydrolysed sludge at 11% DS. There are four no. 1 MW Jenbacher engines operating mainly on biogas. Each pair of engines is fitted with a waste heat boiler with a capacity of one tonne steam per hour. These boilers have sufficient capacity to provide 80% of the steam required for the THP, which in turn provides all the heat for the subsequent digestion in the form of hydrolysed feed. There are two main biogas boilers for top up steam and other uses of the biogas including thermal oxidation of concentrated odours.

No abstract

No abstract

No abstract