Bayer Technology Services GmbH, Chempark Building E41, 51368 Leverkusen, Germany.
Water Res. 2012 Apr 15;46(6):2009-19. doi: 10.1016/j.watres.2012.01.022. Epub 2012 Jan 28.
Phosphorus recovery from sewage sludge will become increasingly important within the next decades due to depletion of mineral phosphorus resources. In this work a new process concept was investigated, which aims at realising phosphorus recovery in a synergistic way with the overall sewage sludge treatment scheme. This process combines a low pressure wet oxidation for sewage sludge decomposition as well as phosphorus dissolution and a nanofiltration process to separate phosphorus from heavy metals and obtain a clean diluted phosphoric acid, from which phosphorus can be recovered as clean fertiliser. It was shown that this process concept is feasible for sewage sludge for wastewater treatment plants that apply enhanced biological removal or precipitation with alumina salts for phosphorus removal. The critical parameter for phosphorus dissolution in the low pressure wet oxidation process is the iron concentration, while in the nanofiltration multi-valent cations play a predominant role. In total, a phosphorus recovery of 54% was obtained for an exemplary wastewater treatment plant. Costs of the entire process are in the same range as conventional sewage sludge disposal, with the benefit being phosphorus recovery and reduced emission of greenhouse gases due to avoidance of sludge incineration.
在未来几十年内，由于矿物磷资源的枯竭，从污水污泥中回收磷将变得越来越重要。在这项工作中，研究了一种新的工艺概念，该概念旨在协同实现整体污水污泥处理方案中的磷回收。该工艺结合了低压湿式氧化技术，用于污水污泥的分解以及磷的溶解，以及纳滤工艺，以将磷与重金属分离，并获得清洁的稀磷酸，从中可以回收清洁的肥料。结果表明，该工艺概念适用于采用强化生物去除或用氧化铝盐进行磷去除的废水处理厂的污水污泥。在低压湿式氧化过程中，磷溶解的关键参数是铁浓度，而在纳滤过程中，多价阳离子起主要作用。总的来说，对于一个典型的污水处理厂，磷的回收率达到了 54%。整个过程的成本与传统的污水污泥处理相同，其优点是由于避免了污泥焚烧，从而回收了磷并减少了温室气体的排放。
