Highly efficient Bucher HPS dewatering technology prior to incineration to achieve a positive energy balance in sludge treatment
Mischler, J-F.1, Courbet, C.2 ,
1Bucher Unipektin AG, 2Suez International
(free)
Abstract
Waste water treatment generates high amounts of sludge and the strategies in the past decades were focussed on disposal routes and reduction of the sludge quantity with minor focus on the energy balance.
Today, biosolids are more and more considered as a source of carbon, energy and are recycled as primary resources.
But, even with advanced sludge treatment processes like AD, there is a loss of energy if a complete sludge treatment energy balance including incineration is made. Reducing organic contents results in a loss of heating value that has to be balanced by a more efficient dewatering, achieving higher sludge cake dryness at low energy cost and without heat consumption.
The Strasbourg (France) case study shows that thanks to the high dry solids content achieved by Bucher HPS sludge press, the waste water treatment plant is changing from a fossil energy consuming sludge process using 1500m3 fuel/year, to a positive energy balance sludge line producing 17-18 GWh/year of bio-methane to sell.
In South of France, the Beziers-Mediterranée agglomeration extended its WWTP and decided to set-up an incineration plant. One of the key parameters was to operate the furnace without neither gas nor fuel consumption. Thanks to advanced dewatering they will be able to fulfil the fixed goals and even fully recover the heat produced by the furnace.
Keywords
Increased Bio-methane production, Bucher HPS, energy recovery, incineration, positive energy balance in sludge treatment, sludge dewatering, Dehydris Twist..
