Bandelin Jochen, Lippert Thomas, Drewes Jörg E, Koch Konrad
Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany.
Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany.
Ultrason Sonochem. 2018 Apr;42:672-678. doi: 10.1016/j.ultsonch.2017.12.025. Epub 2017 Dec 16.
The generation of cavitation fields for the pre-treatment of anaerobic sludge was studied by means of a novel acoustic measuring system. The influence of different reactor dimensions (i.e., choosing reaction chamber widths of 40, 60 and 80 mm) on the cavitation intensity was determined at various solid contents, flow rates and static pressures. Results suggest that the cavitation intensity is significantly reduced by the sonication of liquids with a high solid content. By increasing the pressure to 1 bar, the intensity of bubble implosions can be enhanced and the sound attenuation in the solid fraction is partly compensated compared to ambient pressure. However, a further increase in pressure to 2 bars has a detrimental effect due to the suppression of powerful bubbles. A reduction of the reactor gap permits an intensification of the treatment of waste activated sludge (WAS) by concentrating the ultrasound power from 6 to 18 dB. This effect is less relevant in digested sludge (DS) with its markedly lower total solids content (2.2% vs. 6.9% of solids in WAS). Increasing the flow rate, resulting in a flow velocity of up to 7 m/min, has no influence on the cavitation intensity. By adapting the reactor design and the static pressure to the substrate characteristics, the intensity of the sonication can be notably improved. This allows the design of sonication devices that are suitable for the intensive treatment of wastewater sludge.
通过一种新型声学测量系统研究了用于厌氧污泥预处理的空化场的产生。在不同的固体含量、流速和静压下，确定了不同反应器尺寸（即选择40、60和80毫米的反应室宽度）对空化强度的影响。结果表明，高固体含量液体的超声处理会显著降低空化强度。与环境压力相比，将压力增加到1巴，可以增强气泡内爆的强度，并部分补偿固体部分的声衰减。然而，将压力进一步增加到2巴会产生不利影响，因为强大的气泡受到抑制。减小反应器间隙可通过将超声功率从6分贝提高到18分贝来强化对剩余活性污泥（WAS）的处理。在总固体含量明显较低的消化污泥（DS）中（WAS中的固体含量为6.9%，而DS中为2.2%），这种效果不太明显。将流速提高到最高7米/分钟，对空化强度没有影响。通过使反应器设计和静压适应底物特性，可以显著提高超声处理的强度。这使得能够设计出适用于深度处理废水污泥的超声处理装置。
