Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, China; Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing, China.
College of Environment and Ecology, Chongqing University, Chongqing, China.
Waste Manag. 2024 Jun 15;182:237-249. doi: 10.1016/j.wasman.2024.04.038. Epub 2024 Apr 26.
The effectiveness of dehydration and utilization processes for citric acid dewatered sludge is hampered by its high concentrations of polysaccharides, proteins, and water-binding properties of microbial extracellular polymers (EPS). This research explores the efficacy and mechanisms involved in extracting water from this type of sludge using biological drying technology, with varying rates of ventilation. Especially pertinent was the use of low ventilation rates as control variables. Our results suggest that a scheduled intermittent ventilation at lower rates allows for the most efficient removal of water, achieving a rate of 41.71 % within eight days, according to the zero-order kinetic model. Remarkably, the peak temperature registered was 60 °C, reaching this threshold in just 0.1 days and maintaining high temperatures for approximately 5.9 days. Component analysis of organic matter illustrated a preferential degradation process for lipids under these ventilation conditions which is pivotal for releasing and transforming bound water for efficient extraction, as well as facilitating the breakdown of easily hydrolysable materials. Further, polysaccharide/protein (EPS) decomposition contributed to water removal, though less significantly. The periodic ventilation strategy allowed for the maximum cumulative temperature to be sustained, demonstrating superior efficiency in harnessing bio-generated heat (82.77 % for water evaporation), resulting in dry sludge suitable for self-sustained combustion at relatively low cost ($26.61/t). Highlighted by this study is the considerable potential of energy-efficient ventilation methods in the biological drying treatment of citric acid fermented sludge and similar industrial waste materials.
柠檬酸脱水污泥由于其高浓度的多糖、蛋白质和微生物胞外聚合物 (EPS) 的水结合特性，阻碍了其脱水和利用过程的有效性。本研究探讨了使用生物干燥技术从这种污泥中提取水分的效果和机制，采用不同的通风速率。特别是使用低通风率作为控制变量尤为重要。我们的结果表明，采用较低速率的间歇式通风可以更有效地去除水分，根据零级动力学模型，在八天内可达到 41.71%的去除率。值得注意的是，记录到的峰值温度为 60°C，仅在 0.1 天内达到此阈值，并保持高温约 5.9 天。有机物成分分析表明，在这些通风条件下，脂质优先降解，这对于释放和转化结合水以进行有效提取以及促进易水解物质的分解至关重要。此外，多糖/蛋白质 (EPS) 的分解有助于去除水分，但效果不那么显著。周期性通风策略允许维持最大累积温度，从而在利用生物产生的热量方面表现出更高的效率（用于蒸发水的 82.77%），从而产生适合以相对较低成本（$26.61/t）进行自持燃烧的干污泥。本研究强调了节能通风方法在柠檬酸发酵污泥和类似工业废物的生物干燥处理中的巨大潜力。
