Abstract
The impact of membrane surface characteristics and NOM on membrane performance has been investigated for varying pretreatment and membranes in a field study. Surface charge, hydrophobicity and roughness varied significantly among the four membranes used in the study. The membranes were tested in parallel following two different pretreatment processes, an enhanced Zenon ultrafiltration process (ZN) and a compact CSF process (Superpulsator (SP)) prior to RO membrane treatment for a total of eight integrated membrane systems. All membrane systems were exposed to the similar temperature, recovery and flux as well as chemical dosage. The membrane feed water qualities were statistically equivalent following ZN pretreatment and SP pretreatment except for NOM and SUVA. Membrane surface characteristics, NOM and SUVA measurements were used to describe mass transfer in a low-pressure RO integrated membrane system. Solute and water mass transfer coefficients (MTCs) were investigated for dependence on membrane surface properties and NOM mass loading. Inorganic MTCs were accurately described by a Gaussian distribution curve. Water productivity decreased with NOM loading and increased with contact angle and roughness. The negative effects of NOM loading on productivity were reduced as the negative charge on the membrane surface increased. Inorganic MTCs were also correlated to surface hydrophobicity and surface roughness. The permeability change of identical membranes was related to NOM loading, hydrophobicity and roughness. Organic fouling as measured by water, organic and inorganic mass transfer was less for membranes with higher hydrophilicity and roughness.
| Original language | English |
|---|---|
| Pages (from-to) | 1233-1244 |
| Number of pages | 12 |
| Journal | Water Research |
| Volume | 39 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2005 Apr |
| Externally published | Yes |
Bibliographical note
Funding Information:Membrane contact angle and roughness by pretreatment vs. for Na and Cl are shown in Figs. 8 and 9 . Although there was no statistical difference in the K s 's, there was a statistical difference and a trend in by membrane and pretreatment. As shown in Fig. 8 , increased with increasing contact angle (hydrophobicity) and for membranes receiving ZN pretreated water were lower than for membrane receiving SP pretreated water. NOM loading and SUVA were higher in the ZN pretreated water, which caused more organic fouling and higher As noted, this dynamic hydrophobic film increased with NOM loading and reduced productivity and salt passage. This phenomenon is supported by Fig. 8 .
Keywords
- Integrated membrane systems
- Membrane surface properties
- Natural organic matter
- Solute mass transfer
- Water mass transfer
ASJC Scopus subject areas
- Environmental Engineering
- Civil and Structural Engineering
- Ecological Modelling
- Water Science and Technology
- Waste Management and Disposal
- Pollution