School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan 430070, China E-mail:
China Machinery International Engineering Design & Research Institute Company, Limited, No. 18 Shaoshan Middle Road, Changsha 410007, China.
Water Sci Technol. 2020 Dec;82(12):2975-2989. doi: 10.2166/wst.2020.541.
Rejected water from sludge processing in wastewater treatment plants (WWTPs) is very harmful due to its high concentration of ammonia nitrogen and phosphorus. It is therefore necessary to find a low-cost and convenient technique to simultaneously remove ammonia nitrogen and phosphorus from rejected water. In this study, natural granular zeolite was modified by NaCl and La(OH) to obtain a new material (Na@La-MZP), with several advantages compared with powdered zeolite. Na@La-MZP could remove 92.61% ammonia nitrogen (50 mg/L) and 99.01% phosphate (60 mg/L) at the optimal conditions of dosage 12.5 g/L, initial pH 6.0 and reaction time 12 hours, which enabled the effluent to satisfy the discharge standard (GB 18918-2002) for municipal WWTPs in China. The maximum adsorption capacity of Na@La-MZP was determined as 17.92 mg NH-N/g and 9.53 mg P/g by the Langmuir isotherm. Pseudo-second-order kinetics could well illustrate the adsorption process and show that the ammonia nitrogen and phosphate can be degraded by chemical reaction. The characterizations of Na@La-MZP confirmed the removal mechanism of ammonia nitrogen and phosphate. The Na@La-MZP still maintained more than 75% removal efficiency after five reuses. Furthermore, the estimated cost of this treatment method was 0.22 $/m rejected water.
污水处理厂（WWTP）中污泥处理产生的废水因氨氮和磷浓度高而极具危害性。因此，有必要找到一种低成本且方便的技术，同时去除废水中的氨氮和磷。在本研究中，采用 NaCl 和 La(OH)3 对天然粒状沸石进行改性，得到一种新型材料（Na@La-MZP），与粉末沸石相比具有多个优势。在投加量为 12.5 g/L、初始 pH 值为 6.0 和反应时间为 12 小时的最佳条件下，Na@La-MZP 可去除 92.61%的氨氮（50 mg/L）和 99.01%的磷酸盐（60 mg/L），使出水满足中国城市污水处理厂（GB 18918-2002）的排放标准。通过 Langmuir 等温线，确定 Na@La-MZP 的最大吸附容量为 17.92 mg NH-N/g 和 9.53 mg P/g。准二级动力学可以很好地说明吸附过程，表明氨氮和磷酸盐可以通过化学反应降解。Na@La-MZP 的特性证实了去除氨氮和磷的机制。经过五次重复使用后，Na@La-MZP 仍保持超过 75%的去除效率。此外，这种处理方法的估计成本为 0.22 美元/立方米废水。
