16th September 2013
The Long Reach project is a first of its kind in the UK. Thames water have selected AECOM as main contractor with Cambi as its specialist sub-contractor to build an upgrade to its sludge digestion plant in at Long Reach STW, in NW Kent. The plant has sewage treatment design capacity for 840,000 people equivalent and digests its sludge for use in agriculture as a fertilizer.
The aim of the project is to make the site more self sufficient in energy, and to produce a lower volume of final biosolids that can meet a higher treated standard and that has superior storage qualities without building further digesters. To do this Thames devised a system of hydrolysing mainly the secondary sludge from the treatment process and feeding this in admixture to the existing digesters. This has a number of advantages:
Thames Water has tested this system rigorously in their research labs and in addition has devised a system of serial digestion that will dramatically reduce the pathogen content of the sludge. At full scale this will comprise feed the mixed heated sludge to a bank of existing primary digesters and then over spilling in series to 3 of the existing digesters in turn to give an extended period of pathogen die off and secondary biogas production.
The CambiTHP™ system will comprise a second generation Cambi B6 x 3 continuous batch system that is extremely compact and that can be assembled on site in a matter of days. The system is designed to operate on steady steam consumption from the engine waste heat boilers.
Veolia has invested over £14 million in its Seafield Waste Water Treatment facility in Edinburgh on thermal hydrolysis technology. The process will help produce over 100 tonnes per day of thermal hydrolysis cake, a new product to add key nutrients back into farming land.