Abstract
Currently, disintegration methods are applied to increase the biogas production in fermentation or in case of operational problems (floating and bulking sludge). In order to increase biogas production, waste activated sludge is disintegrated. Here, mainly mechanical disintegration methods e.g. ball mill, ultrasound and lysate-thickening centrifuge are used.
Turovskiy (2006) states, that disintegration of stabilized sludge before dewatering influences the dewaterability of sludge by. Here, during disintegration the sludge flakes are disrupted and bound water becomes available for gravitational means of dewatering. The increase in total solids concentration in dewatered sludge goes along with the reduction of water contained in dewatered sludge. This reduces the total amount of sludge for disposal and increases the possibilities of sludge utilization in waste to energy as less water needs to be evaporated by drying or during incineration.
The contribution is devoted to the design of a sewage sludge disintegration unit with the capacity of 10.8 t/d of a liquid sludge (refers to a wastewater treatment plant capacity of 10,000 population equivalents). Used material properties and insights have been gained in experimental work. Based on measured data, a pressure vessel was proposed. Further, stress analysis, considerations concerning the vessel heating and an economical evaluation of the process was elaborated. In the evaluation, a payback period of approx. 15 y is determined, which emerges from the savings in sludge disposal.
