污水處理廠磷組分特性分析及回收技術(shù)措施
張鈺婷1,2, 尚巍2*, 邱順添1, 鄭興燦2, 孫永利2, 李鵬峰2, 顧淼2
1. 天津大學(xué)環(huán)境科學(xué)與工程學(xué)院,天津 300072;
2. 中國(guó)市政工程華北設(shè)計(jì)研究總院有限公司,天津 300381
摘要 磷是生命活動(dòng)不可或缺的元素,然而目前磷礦石儲(chǔ)存量已無法滿足未來人類對(duì)磷的需求。隨著國(guó)家不斷加快推動(dòng)城鎮(zhèn)生活污水資源化利用,對(duì)城市污水中磷資源回收是實(shí)現(xiàn)循環(huán)經(jīng)濟(jì)的關(guān)鍵。從污水污泥中回收磷資源,可補(bǔ)充全球磷消耗量的20%,可有效緩解磷資源危機(jī)。本文采用31P NMR方法全面解析污水處理廠中污水及污泥不同磷組分賦存形態(tài),重點(diǎn)分析磷組分在污水廠中遷移轉(zhuǎn)化特性及殘留磷組分,闡明污水及污泥中磷回收潛力,提出污水及污泥中磷回收技術(shù)措施,以期為污水及污泥中磷資源的回收與高效利用奠定理論基礎(chǔ)。
關(guān)鍵詞:城市污水、磷組分特性、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
磷是組成生命物質(zhì)必不可少的元素之一,參與生命體的能量循環(huán)。磷對(duì)人類的生活至關(guān)重要[1],是構(gòu)成日常生活使用品,如洗滌劑、食品添加劑、飼料添加劑等的主要原料之一。此外,磷作為一種戰(zhàn)略性資源,對(duì)全球糧食生產(chǎn)的貢獻(xiàn)具有不可替代的作用。隨著電動(dòng)車行業(yè)的迅猛發(fā)展,對(duì)磷酸鐵鋰電池的需求量急劇增加。然而,中國(guó)磷礦豐而不富,截至2018年底,中國(guó)磷礦資源儲(chǔ)存量為32億噸[2],品位在30%以上的磷礦石占比不足10%,平均品位僅為17%[3]。不僅如此,我國(guó)70%的磷礦為膠磷礦,雜質(zhì)較多,礦選難度大,磷資源利用率低。因此,中國(guó)國(guó)土資源部列出的2010年后20個(gè)不能滿足國(guó)民經(jīng)濟(jì)發(fā)展需求的礦種中包含磷礦[4],我國(guó)已然到了必須考慮實(shí)施磷回收戰(zhàn)略的時(shí)刻。
與世界磷資源極其匱乏相矛盾的是水體中過量的磷導(dǎo)致水體富營(yíng)養(yǎng)化污染,致使藻類大量繁殖[5]。在此情況下,污水處理廠傳統(tǒng)化學(xué)除磷方法通過加大藥劑投加量以強(qiáng)化除磷。然而,在回流污泥中可能殘留部分化學(xué)藥劑,化學(xué)藥劑會(huì)與生物系統(tǒng)中磷酸鹽生成難溶性鹽組分,阻礙聚磷菌利用磷酸鹽合成貯存于細(xì)胞內(nèi)的聚磷酸鹽過程,使生物系統(tǒng)無法正常發(fā)揮除磷功能[6]。因此,污水處理技術(shù)應(yīng)該轉(zhuǎn)變傳統(tǒng)觀念,改變污水中磷僅去除而未回收的現(xiàn)狀。若能實(shí)現(xiàn)大規(guī)模從城鎮(zhèn)污水中回收磷,不僅能提供全球所需磷礦石的20%左右,同時(shí)能夠降低污水處理廠的除磷成本以及減少生物系統(tǒng)除磷藥劑殘留量。
本文詳細(xì)解析污水處理廠中污水及污泥不同磷組分賦存形態(tài),闡明污水及污泥中磷回收潛力,提出污水及污泥中磷回收技術(shù)措施,以期為污水及污泥中磷資源的回收與高效利用奠定理論基礎(chǔ)。