Vaxelaire S, Gonze E, Merlin G, Gonthier Y
Laboratoire Optimisation de la Construction et Ingénierie de l'Environnement, Polytech'Savoie, Université de Savoie, 73376 Le Bourget du Lac, France.
Environ Technol. 2008 Dec;29(12):1307-20. doi: 10.1080/09593330802379649.
Conventional activated sludge wastewater treatment plants currently produce a large quantity of excess sludge. To reduce this sludge production and to improve sludge characteristics in view of their subsequent elimination, an ultrasonic cell disintegration process was studied. In a lab-scale continuous flow pilot plant, part of the return sludge was sonicated by low-frequency and high-powered ultrasound and then recycled to the aeration tank. Two parallel lines were used: one as a control and the other as an assay with ultrasonic treatment. The reactors were continuously fed with synthetic domestic wastewater with a COD (chemical oxygen demand) of approximately 0.5 g l(-) corresponding to a daily load of 0.35-0.50 kg COD kg(-1) TS d(-1). Removal efficiencies (carbon, particles), excess sludge production and sludge characteristics (particle size distribution, mineralization, respiration rate, biological component) were measured every day during the 56-day experiment. This study showed that whilst organic removal efficiency did not deteriorate, excess sludge production was decreased by about 25-30% by an ultrasonic treatment. Several hypotheses are advanced: (i) the treatment made a part of the organic matter soluble as a consequence of the floc disintegration, and optimised the conversion of the carbonaceous pollutants into carbon dioxide and (ii) the treatment modified the physical characteristics of sludge by a mechanical effect: floc size was reduced, increasing the exchange surface and sludge activity. The originality of this study is that experiments were conducted in a continuous-flow activated sludge reactor rather than in a batch reactor.
传统的活性污泥污水处理厂目前会产生大量的剩余污泥。为了减少污泥产量，并鉴于后续污泥的消除来改善污泥特性，对超声细胞破碎工艺进行了研究。在实验室规模的连续流中试装置中，一部分回流污泥通过低频大功率超声进行处理，然后再循环至曝气池。使用了两条平行线路：一条作为对照，另一条作为超声处理的试验线路。向反应器中连续投加化学需氧量（COD）约为0.5 g l(-1)的模拟生活污水，对应于每日负荷为0.35 - 0.50 kg COD kg(-1) TS d(-1)。在为期56天的实验期间，每天测量去除效率（碳、颗粒）、剩余污泥产量和污泥特性（粒度分布、矿化、呼吸速率、生物成分）。该研究表明，虽然有机去除效率没有下降，但通过超声处理剩余污泥产量降低了约25 - 30%。提出了几个假设：（i）由于絮体破碎，该处理使一部分有机物溶解，并优化了含碳污染物向二氧化碳的转化；（ii）该处理通过机械作用改变了污泥的物理特性：絮体尺寸减小，增加了交换表面积和污泥活性。本研究的独特之处在于实验是在连续流活性污泥反应器中进行的，而不是在间歇反应器中。
