Pollution Prevention and Resource Recovery Chair Group, UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands.
J Environ Manage. 2013 Dec 15;131:82-91. doi: 10.1016/j.jenvman.2013.09.025. Epub 2013 Oct 21.
Construction and demolition debris (CDD) contains high levels of sulfate that can cause detrimental environmental impacts when disposed without adequate treatment. In landfills, sulfate can be converted to hydrogen sulfide under anaerobic conditions. CDD can thus cause health impacts or odor problems to landfill employees and surrounding residents. Reduction of the sulfate content of CDD is an option to overcome these problems. This study aimed at developing a biological sulfate removal system to reduce the sulfate content of gypsum contaminated CDD in order to decrease the amount of solid waste, to improve the quality of CDD waste for recycling purposes and to recover sulfur from CDD. The treatment leached out the gypsum contained in CDD by water in a leaching column. The sulfate loaded leachate was then treated in a biological sulfate reducing Upflow Anaerobic Sludge Blanket (UASB) reactor to convert the sulfate to sulfide. The UASB reactor was operated at 23 ± 3 °C with a hydraulic retention time and upflow velocity of 15.5 h and 0.1 m h(-1), respectively while ethanol was added as electron donor at a final organic loading rate of 3.46 g COD L(-1) reactor d(-1). The CDD leachate had a pH of 8-9 and sulfate dissolution rates of 526.4 and 609.8 mg L(-1) d(-1) were achieved in CDD gypsum and CDD sand, respectively. Besides, it was observed that the gypsum dissolution was the rate limiting step for the biological treatment of CDD. The sulfate removal efficiency of the system stabilized at around 85%, enabling the reuse of the UASB effluent for the leaching step, proving the versatility of the bioreactor for practical applications.
建筑和拆除废物 (CDD) 含有高水平的硫酸盐，如果在没有适当处理的情况下处置，可能会对环境造成有害影响。在垃圾填埋场中，硫酸盐在厌氧条件下可转化为硫化氢。因此，CDD 可能会对垃圾填埋场员工和周围居民的健康产生影响或造成气味问题。减少 CDD 中的硫酸盐含量是克服这些问题的一种选择。本研究旨在开发一种生物硫酸盐去除系统，以降低受石膏污染的 CDD 中的硫酸盐含量，从而减少固体废物的数量，提高 CDD 废物的回收质量，并从 CDD 中回收硫。该处理方法通过淋滤柱中的水浸出 CDD 中所含的石膏。然后，将负载硫酸盐的浸出液在生物硫酸盐还原上流厌氧污泥床 (UASB) 反应器中处理，将硫酸盐转化为硫化物。UASB 反应器在 23 ± 3°C 下运行，水力停留时间和上流速度分别为 15.5 小时和 0.1 米/小时，同时添加乙醇作为电子供体，最终有机负荷率为 3.46 克 COD/L 反应器/d。CDD 浸出液的 pH 值为 8-9，在 CDD 石膏和 CDD 砂中分别实现了 526.4 和 609.8 mg/L/d 的硫酸盐溶解速率。此外，观察到石膏溶解是生物处理 CDD 的限速步骤。该系统的硫酸盐去除效率稳定在 85%左右，使 UASB 出水可用于淋滤步骤的再利用，证明了该生物反应器在实际应用中的多功能性。
