Seawater and Brackish‐Water Desalination with Membrane Operations

Semiat, Raphael; Hasson, David

doi:10.1002/9783527631407.ch5

Cited by 6 publications

(27 citation statements)

References 34 publications

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“…Comparisons of predictions from currently available silica solubility data and experimental research and operation of RO treatment plants reveals that the current data are inadequate to explain silica precipitation for some waters with relatively low silica concentrations. Although mitigation of silica precipitation is attempted, most techniques are ineffective or lead to even higher silica scale formation on the RO membrane surface (Semiat 1996, 20012, 2003, Demakis 2003. Presently, there is no reliable way to predict silica scale formation.…”

Section: Problem Statementmentioning

confidence: 99%

“…Operating near the silica solubility limit leads also to scaling (Coronell 2006, Demadis 2005. Besides fouling and scaling there are other causes of flux decline in membrane processes, including both membrane ageing and degradation of the membrane material (Brant 2012, Semiat 1996. Recent research suggests that the chemical and physical properties of the membrane materials may be the primary controlling parameters for membrane fouling in all membrane separations (Cob 2012, Wood 2011.…”

Section: Ro Technologymentioning

confidence: 99%

“…It is believed that the mechanism of water and salt separation by RO is not fully understood (Cob 2012, Semiat 1996. The theory suggests that the chemical nature of the membrane is such that it will absorb and pass water preferentially to dissolved salts at the solid/liquid interface.…”

Section: Ro Processmentioning

confidence: 99%

“…As in crystallisation, it has been observed that an initial nucleation phase is followed by a growth phase. Nucleation was found to be a function of product water flux, particle size, and the number of nucleation sites (Brant, 2012, Ning 2010, Semiat 1996. The rate of growth was controlled by the product flux, the rates of metal and silica polymerization, and shear forces in the bulk flow.…”

Section: Membrane Foulingmentioning

confidence: 99%

“…For example, Semiat (1996), and Yong (1993 developed practical tools to study silica scale formation on the membrane surface that accounts for pH, silica concentrations, and silica solubility in a particular water matrix. Analysis of different approaches to silica polymerisation and scale formation studies showed that silica fouling needs to be studied empirically, for each specific water matrix.…”

mentioning

confidence: 99%

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Silica fouling in coal seam gas water reverse osmosis desalination

Lunevich

Sartipy

Milne

et al. 2017

Environ. Sci.: Water Res. Technol.

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i AbstractSilica precipitation and silica scale formation on membrane surfaces in RO desalination present a significant operational challenge in water purification. Silica scale formation on the membrane surface leads to flux decline, RO system productivity lost, membrane degradation, and increased cost of chemicals. In spite of the apparent simplicity of silica's composition and scale formation on the membrane surface, fundamental questions and empirical knowledge persist about the formation, solubility and behaviour of silica species during the silica polymerisation, precipitation and scale formation.The broad objective of the present study was to define conditions and factors affecting silica polymerisation and precipitation in coal seam gas (CSG) waters in Australia. The scope of the problem was narrowed to focus on dissolved silica species studied by 29 Si NMR spectroscopy, removal of silica by coagulation as pre-treatment step for RO desalination and silica fouling patterns in RO desalination for a range of salinities in both synthetic and CSG waters to develop a conceptual model of silica precipitation and deposition on the membrane surface.The CSG industry in Australia generates significant quantities of CSG water, especially during the first 3-5 years of reservoir development when the hydraulic pressure needs to be released to extract the gas from coal seam. To avoid high cost of brine treatment and residual disposal frequently requires high recovery RO desalination to treat CSG water to level acceptable for further re-use. Furthermore, CSG waters in Australia have all four critical parameters, which potentially lead to silica precipitation prior it reached the solubility limit. These parameters include medium to high salinity, medium silica concentrations, high alkalinity at pH9 and slightly elevated aluminium concentrations.Practical field, theoretical and laboratory research works have been undertaken to study industry's concerns and bring fundamental and practical solutions to the problem. In Sodium ions depress silica solubility at the same time preventing silica from deposition on the membrane surface. The majority of dissolved silica polymerised in the bulk solution and was discharged in the reject stream of the RO system. To conclude practical silica solubility or the solubility defined empirically is a key for prevention of silica polymerisation in RO desalination systems.iii

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Section: Problem Statementmentioning

confidence: 99%

Section: Ro Technologymentioning

confidence: 99%

Section: Ro Processmentioning

confidence: 99%

Section: Membrane Foulingmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Silica fouling in coal seam gas water reverse osmosis desalination

Lunevich

Sartipy

Milne

et al. 2017

Environ. Sci.: Water Res. Technol.

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A perspective on reverse osmosis water desalination: Quest for sustainability

2017

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Diagnostic analysis of RO desalting treated wastewater

et al. 2008

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Diagnostic analysis of reverse osmosis membranes that are fed with Western Treatment Plant (WTP) recycled water was investigated by both thermodynamic calculations and laboratory experiments, in order to predict the feasibility of RO desalting for WTP. The thermodynamic calculations suggested that RO recoveries of 80-85% were feasible with careful control of feed water pH and the use of chemical additives such as antiscalants and chelating agents, it also predicted the major minerals of concern to be silica, calcium fluoride, calcium carbonate, and calcium phosphate. Following the thermodynamic simulations, diagnostic laboratory experiments were undertaken. The experiments showed that the major contributor to scale formation was indeed calcium phosphate and possibly another calcium based compound, which was strongly suspected to be calcium carbonate. Based on previously published literature that indicated antiscalants did not substantially decrease the scaling effect of calcium phosphate and laboratory tests that indicated controlling the pH to 6.4 in the feed water dramatically reduced scaling formation, it was suggested that the feed water could be controlled by pH adjustments only. Inter-stage pH correction was suggested as an optional technique to enhance the overall water recovery to above 95%.

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Seawater and Brackish‐Water Desalination with Membrane Operations

Cited by 6 publications

References 34 publications

Silica fouling in coal seam gas water reverse osmosis desalination

Silica fouling in coal seam gas water reverse osmosis desalination

A perspective on reverse osmosis water desalination: Quest for sustainability

Diagnostic analysis of RO desalting treated wastewater

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