Using loose nanofiltration membrane for lake water treatment: A pilot study
- PDF / 628,669 Bytes
- 11 Pages / 595.276 x 785.197 pts Page_size
- 52 Downloads / 159 Views
RESEARCH ARTICLE
Using loose nanofiltration membrane for lake water treatment: A pilot study Danyang Liu1,#, Johny Cabrera1,#, Lijuan Zhong2, Wenjing Wang2, Dingyuan Duan2, Xiaomao Wang (✉)1,*, Shuming Liu1, Yuefeng F. Xie1,3 1 State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China 2 Chengdu Xingrong Environmental Co., Ltd., Chengdu 610041, China 3 Civil and Environmental Programs, Penn State University, Middletown, PA 17057, USA
HIGHLIGHTS
GRAPHIC ABSTRACT
• A pilot study was conducted for drinking water treatment using loose NF membranes. • The membranes had very high rejection of NOM and medium rejection of Ca2+/Mg2+. • Organic fouling was dominant and contribution of inorganic fouling was substantial. • Both organic and inorganic fouling had spatial non-uniformity on membrane surface. • Applying EDTA at basic conditions was effective in removing membrane fouling.
ABSTRACT ARTICLE INFO Article history:
Received 3 June 2020 Revised 21 September 2020 Accepted 25 September 2020 Available online 4 November 2020 Keywords: Nanofiltration Drinking water Membrane fouling Aluminum carryover Chemical cleaning
Nanofiltration (NF) using loose membranes has a high application potential for advanced treatment of drinking water by selectively removing contaminants from the water, while membrane fouling remains one of the biggest problems of the process. This paper reported a seven-month pilot study of using a loose NF membrane to treat a sand filtration effluent which had a relatively high turbidity (~0.4 NTU) and high concentrations of organic matter (up to 5 mg/L as TOC), hardness and sulfate. Results showed that the membrane demonstrated a high rejection of TOC (by>90%) and a moderately high rejection of two pesticides (54%–82%) while a moderate rejection of both calcium and magnesium (~45%) and a low rejection of total dissolved solids (~27%). The membrane elements suffered from severe membrane fouling, with the membrane permeance decreased by 70% after 85 days operation. The membrane fouling was dominated by organic fouling, while biological fouling was moderate. Inorganic fouling was mainly caused by deposition of aluminum-bearing substances. Though inorganic foulants were minor contents on membrane, their contribution to overall membrane fouling was substantial. Membrane fouling was not uniform on membrane. While contents of organic and inorganic foulants were the highest at the inlet and outlet region, respectively, the severity of membrane fouling increased from the inlet to the outlet region of membrane element with a difference higher than 30%. While alkaline cleaning was not effective in removing the membrane foulants, the use of ethylenediamine tetraacetate (EDTA) at alkaline conditions could effectively restore the membrane permeance. © Higher Education Press 2020
1
Introduction
Due to the rapid population growth and economy development, pollution of the aquatic environment becomes a worldwide problem (Kolpin et al., 2002;
Data Loading...
