污水处理厂磷组分特性分析及回收技术措施
张钰婷1,2, 尚巍2*, 邱顺添1, 郑兴灿2, 孙永利2, 李鹏峰2, 顾淼2
1. 天津大学环境科学与工程学院,天津 300072;
2. 中国市政工程华北设计研究总院有限公司,天津 300381
摘要 磷是生命活动不可或缺的元素,然而目前磷矿石储存量已无法满足未来人类对磷的需求。随着国家不断加快推动城镇生活污水资源化利用,对城市污水中磷资源回收是实现循环经济的关键。从污水污泥中回收磷资源,可补充全球磷消耗量的20%,可有效缓解磷资源危机。本文采用31P NMR方法全面解析污水处理厂中污水及污泥不同磷组分赋存形态,重点分析磷组分在污水厂中迁移转化特性及残留磷组分,阐明污水及污泥中磷回收潜力,提出污水及污泥中磷回收技术措施,以期为污水及污泥中磷资源的回收与高效利用奠定理论基础。
关键词:城市污水、磷组分特性、磷回收
Characteristic Analysis of Phosphorus Components in Sewage Treatment Plants and Technical Measures for Recovery
ZHANG Yu-ting1,2, SHANG Wei2*, KHU Soon-Thiam1, ZHENG Xing-can2, SUN Yong-li2, LI Peng-feng2, GU Miao2
(1. School of Environment Science & Engineering, Tianjin University, Tianjin 300072, China; 2. North China Municipal Engineering Design & Research Institute Co. Ltd., Tianjin 300381, China)
Abstract: Phosphorus is an indispensable element for life activities, but the current storage of phosphate rock can no longer meet the future human demand for phosphorus. With the continuous development of resources reuse in urban domestic sewage, the recovery of phosphorus is the key to realizing a circular economy. About 20% of global phosphorus consumption could be replenished through recovery of phosphorus from sewage and sludge, effectively alleviating the shortage of phosphorus resources. In this paper, the composition structure of different phosphorus components in sewage and sludge from sewage treatment plants are analyzed by 31P NMR characteristics. The migration and transformation characteristics of phosphorus components in sewage treatment were analyzed, and the potential of phosphorus recovery in sewage and sludge was clarified. In addition, a new method of phosphorus recovery from sewage and sludge was proposed, which provided a theoretical basis for phosphorus recovery and efficient utilization.
Keyword: municipal sewage, phosphorus component characteristics, phosphorus recovery
引言
磷是组成生命物质必不可少的元素之一,参与生命体的能量循环。磷对人类的生活至关重要[1],是构成日常生活使用品,如洗涤剂、食品添加剂、饲料添加剂等的主要原料之一。此外,磷作为一种战略性资源,对全球粮食生产的贡献具有不可替代的作用。随着电动车行业的迅猛发展,对磷酸铁锂电池的需求量急剧增加。然而,中国磷矿丰而不富,截至2018年底,中国磷矿资源储存量为32亿吨[2],品位在30%以上的磷矿石占比不足10%,平均品位仅为17%[3]。不仅如此,我国70%的磷矿为胶磷矿,杂质较多,矿选难度大,磷资源利用率低。因此,中国国土资源部列出的2010年后20个不能满足国民经济发展需求的矿种中包含磷矿[4],我国已然到了必须考虑实施磷回收战略的时刻。
与世界磷资源极其匮乏相矛盾的是水体中过量的磷导致水体富营养化污染,致使藻类大量繁殖[5]。在此情况下,污水处理厂传统化学除磷方法通过加大药剂投加量以强化除磷。然而,在回流污泥中可能残留部分化学药剂,化学药剂会与生物系统中磷酸盐生成难溶性盐组分,阻碍聚磷菌利用磷酸盐合成贮存于细胞内的聚磷酸盐过程,使生物系统无法正常发挥除磷功能[6]。因此,污水处理技术应该转变传统观念,改变污水中磷仅去除而未回收的现状。若能实现大规模从城镇污水中回收磷,不仅能提供全球所需磷矿石的20%左右,同时能够降低污水处理厂的除磷成本以及减少生物系统除磷药剂残留量。
本文详细解析污水处理厂中污水及污泥不同磷组分赋存形态,阐明污水及污泥中磷回收潜力,提出污水及污泥中磷回收技术措施,以期为污水及污泥中磷资源的回收与高效利用奠定理论基础。