Effects of the initial pH on the process of forward osmosis for concentration of municipal sewage and phosphorus recovery
WANG Mei-ling, WANG Ce, LI Yong-mei
State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
Abstract：In order to recover phosphorus and water resources from municipal sewage and reduce the reactor volume for subsequent treatment, forward osmosis membrane was used to concentrate municipal sewage. The effect of different initial pH on municipal sewage concentration and phosphorus recovery was explored. When forward osmosis concentration test was carried out with synthetic sewage, as the initial pH of feed solution (FS) was raised to 9.5 and the volume of FS was concentrated to 1/10 of the initial, the adsorbed phosphorus on the membrane and the spacer was about 44% of the initial total, which was conductive to phosphorus recovery. When FS was real municipal sewage and the initial pH of it was 9.5, there were agglomerated spherical particles on the fouled membrane surface, making the membrane surface pollutants more easily cleaned under this condition, and the water flux of membrane after cleaning was higher than that under the unadjusted pH conditions. After in-situ ultrasonic cleaning, the concentrated sewage became a suspension solution. The main components of the collected precipitate were CaCO3, struvite and magnesium phosphate. When initial pH was 9.5, the contents of CaCO3 and struvite in the resulting precipitate was higher than that under the other operating conditions. After adjusting the initial pH of the municipal sewage to 9.5 and concentrating it for three consecutive runs of 42 hours, the volume of the sewage was concentrated to about 8 times of the original volume, and the phosphorus recovery reached 63.9%. After the concentration is completed, the membrane was firstly subjected to in-situ ultrasonic cleaning, and then to chemical cleaning with alkali washing and acid washing. After cleaning, the water flux was about 78% of the initial membrane flux; the pH of the concentrated sewage was between 8.5~9.1; the COD/TN value was significantly increased from 3.6 to 11.5, which was conducive to the subsequent nitrogen and phosphorus removal process.
王美玲, 王策, 李咏梅. 初始pH值对正渗透浓缩城市污水和回收磷的影响[J]. 中国环境科学, 2021, 41(2): 660-668.
WANG Mei-ling, WANG Ce, LI Yong-mei. Effects of the initial pH on the process of forward osmosis for concentration of municipal sewage and phosphorus recovery. CHINA ENVIRONMENTAL SCIENCECE, 2021, 41(2): 660-668.
Zhang X, Ning Z, Wang D K, et al. Processing municipal wastewaters by forward osmosis using CTA membrane[J]. Journal of Membrane Science, 2014,468:269-275.
[2]
Zhao P, Gao B, Yue Q, et al. The performance of forward osmosis process in treating the surfactant wastewater:The rejection of surfactant, water flux and physical cleaning effectiveness[J]. Chemical Engineering Journal, 2015,281:688-695.
[3]
Lee S, Boo C, Elimelech M, et al. Comparison of fouling behavior in forward osmosis (FO) and reverse osmosis (RO)[J]. Journal of Membrane Science, 2010,365(1/2):34-39.
[4]
张高旗,刘海宁,张凯松.正渗透处理生活污水过程中的膜污染研究[J]. 中国环境科学, 2013,33(12):2170-2175.Zhang G Q, Liu H N, Zhang K S. Characterization of membrane fouling in forward osmosis treating municipal wastewater[J]. China Environmental Science, 2013,33(12):2170-2175.
[5]
Wang C, Wang M, LI Y. Effects of sodium dodecyl sulfate on forward osmosis membrane fouling and its cleaning[J]. Chemosphere, 2020,257:127180.
[6]
Wang C, LI Y. Permeation of greywater constituents in an aquaporin based biomimetic forward osmosis membrane process:experimental performance and modeling[J]. Journal of Chemical Technology and Biotechnology, 2019,94(5):1567-75.
[7]
王美玲,王策,李咏梅.利用水通道蛋白正渗透膜浓缩生活污水[J]. 中国环境科学, 2020,40(1):269-79.Wang M L, Wang C, Li Y M. Experimental study on concentrating domestic sewage using aquaporin biomimetic forward osmosis membrane[J]. China Environmental Science, 2020,40(1):269-279.
[8]
Chen L, Gu Y S, Cao C Q, et al. Performance of a submerged anaerobic membrane bioreactor with forward osmosis membrane for low-strength wastewater treatment[J]. Water Research, 2014,50:114-23.
[9]
Akther N, Sodiq A, Giwa A, et al. Recent advancements in forward osmosis desalination:A review[J]. Chemical Engineering Journal, 2015,281:502-22.
[10]
Qiu G L, Law Y M, Das S, et al. Direct and complete phosphorus recovery from municipal wastewater using a hybrid microfiltration-forward osmosis membrane bioreactor process with seawater brine as draw solution[J]. Environmental Science & Technology, 2015, 49(10):6156-63.
[11]
Xie M, Nghiem L D, Price W E, et al. Toward resource recovery from wastewater:Extraction of phosphorus from digested sludge using a hybrid forward osmosis-membrane distillation process[J]. Environ Sci Technol Lett, 2014,1(2):191-5.
[12]
Volpin F, Chekli L, Phuntsho S, et al. Simultaneous phosphorous and nitrogen recovery from source separated urine:A novel application for fertiliser drawn forward osmosis[J]. Chemosphere Environmental Toxicology & Risk Assessment, 2018,203:482-489.
[13]
赵玉鑫,杨静,张军军,等.污水中磷回收方法研究进展[J]. 吉林农业大学学报, 2015,37(6):638-42,48.Zhao Y X, Yang J, Zhang J J, et al. Advances of researches on recovery Technology of Sewage Phosphorus[J]. Journal of Jilin Agricultural University, 2015,37(6):638-642,648.
[14]
Li Y M, Yuan Z W, Zou J T. Struvite pellet crystallization in high-strength nitrogen and phosphorus stream[J]. Water Sci Technol, 2013,68(6):1300-5.
[15]
Song Y H, Hahn H H, Hoffmann E.Effects of solution conditions on the precipitation of phosphate for recovery A thermodynamic evaluation[J]. Chemosphere, 2002,48(10):1029-34.
[16]
国家环境保护总局.水和废水监测分析方法.第4版[M]. 北京:中国环境科学出版社, 2002.Nation environmental protection administration. Water and wastewater monitoring and analysis methods[M]. Beijing, China Environmental Science press, 2002.
[17]
张顺泽.试论废水碱度对活性污泥的影响[J]. 化工环保, 1994,14(1):17-9.Zhang S Y. Discussion on the effect of wastewater alkalinity on activated sludge[J]. Environmental protection of chemical industry, 1994,14(1):17-9.
[18]
Beales N. Adaptation of microorganisms to cold temperatures, weak acid preservatives, low pH, and osmotic stress:A review[J]. Comprehensive Reviews in Food Science and Food Safety, 2004,3(1):1-20.
[19]
Stronach S M, Rudd T, Lester J N. Anaerobic digestion processes in industrial waste-water treatment[M]. Springer-Verlag, 1986.
[20]
Jiang H L, Tay J H, Liu Y, et al. Ca2+ augmentation for enhancement of aerobically grown microbial granules in sludge blanket reactors[J]. Biotechnology Letters, 2003,25(2):95-9.
[21]
Movasaghi Z, Rehman S, Ur Rehman D I. Fourier transform infrared (FTIR) spectroscopy of biological tissues[J]. Applied Spectroscopy Reviews, 2008,43(2):134-79.
[22]
王崇臣,郝晓地.鸟粪石分析与表征技术综述[J]. 环境科学与管理, 2009,12:88-91.Wang C C, He X D. The review of analysis and characterization technologies for struvite[J]. Environmental Science and Management, 2009,12:88-91.
[23]
李咏梅,平倩,马璐艳.鸟粪石成粒法回收污泥液中的磷及颗粒品质表征[J]. 同济大学学报(自然科学版), 2014,42(6):912-7.Li Y M, Ping Q, Ma L Y. Struvite pellet crystallization for phosphorus recovery from sludge liquor and characterization of pellet quality[J]. Journal of Tongji University (Natural Science), 2014,42(6):912-917.
[24]
Bowen W R, Doneva T A. Atomic force microscopy studies of membranes:Effect of surface roughness on double-layer interactions and particle adhesion[J]. Journal of Colloid & Interface, 2000,229(2):544-9.
