Changes in feedwater organic matter concentrations based on intake type and pretreatment processes at SWRO facilities, Red Sea, Saudi Arabia

Dehwah, Abdullah H.A.; Li, Sheng; Al-Mashharawi, Samir; Winters, Harvey; Missimer, Thomas M.

doi:10.1016/j.desal.2015.01.008

Cited by 32 publications

(17 citation statements)

References 17 publications

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“…Higher salinity sea water with a slightly lower pH occurs in the carbonate sediments directly underlying the nearshore Red Sea bottom as documented by Dehwah and Missimer (). The higher salinity is likely caused by nearshore evaporative concentration which is 2–3 m of evaporation per year and low rates of nearshore circulation (Dehwah et al , ).…”

Section: Methodsmentioning

confidence: 99%

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination

Dehwah

Al-Mashharawi

et al. 2016

Groundwater

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An investigation of a sea water reverse osmosis desalination facility located in western Saudi Arabia has shown that aquifer treatment of the raw sea water provides a high degree of removal of natural organic matter (NOM) that causes membrane biofouling. The aquifer is a carbonate system that has a good hydraulic connection to the sea and 14 wells are used to induce sea water movement 400 to 450 m from the sea to the wells. During aquifer transport virtually all of the algae, over 90% of the bacteria, over 90% of the biopolymer fraction of NOM, and high percentages of the humic substance, building blocks, and some of the low molecular weight fractions of NOM are removed. Between 44 and over 90% of the transparent exopolymer particles (TEP) are removed with a corresponding significant reduction in concentration of the colloidal fraction of TEP. The removal rate for TEP appears to be greater in carbonate aquifers compared to siliciclastic systems. Although the production wells range in age from 4 months to 14 years, no significant difference in the degree of water treatment provided by the aquifer was found.

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Section: Methodsmentioning

confidence: 99%

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination

Dehwah

Al-Mashharawi

et al. 2016

Groundwater

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“…The operating costs of SWRO is very dependent on the complexity of the pretreatment system. The lowest pretreatment costs have been found to occur on SWRO systems that use subsurface intakes that have minimal maintenance and require minimal pretreatment (sand filtration only) [6][7][8][9][10]. The average total water treatment costs for a 100,000 m 3 /day permeate capacity SWRO system using an open-ocean intake ranges from about US$0.80 to US$1.00 per m 3 ( Table 1).…”

Section: Comparison Of Total Water Treatment Costs Of Normal Chemistrmentioning

confidence: 99%

“…While it is unlikely that membrane biofouling can ever be eliminated, the rate of biofouling can be controlled by using extensive pretreatment processes [4,5] designed to remove inorganic and organic particulates including algae, fineorganic solids, and bacteria; and semi-dissolved or dissolved organic matter, such as particulate and colloidal transparent exopolymer particles (TEP) and other sticky polysaccharides that occur mostly within the biopolymer fraction of natural organic matter (NOM) [6]. Many of the precursors to biofouling are also known to be effectively removed by using subsurface intakes, such as conventional vertical wells [7][8][9][10][11] and seabed galleries [12,13].…”

Section: Introductionmentioning

confidence: 99%

Impacts of natural pore-water and offshore aquifer chemistry on the operation and economics of some subsurface intakes types for SWRO plants

Missimer¹,

Watson²,

Maliva³

et al. 2018

Desalination and Water Treatment

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CitationMissimer TM, Watson I, Maliva RG, Ghaffour N, Dehwah AAH, et al. (2018) Impacts of natural pore-water and offshore aquifer chemistry on the operation and economics of some subsurface intakes types for SWRO plants. DESALINATION AND WATER TREATMENT 132: 1-9. Available: http://dx. AbstractHorizontal and slant wells are being investigated as a means of obtaining feed water for seawater reverse osmosis (SWRO) desalination plants. These well types have been touted to produce higher quality seawater that will reduce the rate of membrane biofouling by removing algae, bacteria, transparent exopolymer particles, and other fractions of natural organic matter similar to onshore wells located on the beach. As these new well types are being considered for large-scale use, a careful evaluation of the biogeochemistry of seawater that occurs within the nearshore subsurface sediments is necessary to assess potential impacts to the SWRO process train. A high percentage of the coastlines of the world contain offshore sediments with seawater that is anoxic in nature with significant concentrations of hydrogen sulfide and dissolved organic matter, iron, manganese, and heavy metals. Where dissolved iron and/or manganese occur at concentrations greater than 1 mg/L in raw seawater, there can be problematical for direct treatment using the SWRO process. Membrane scaling and biofouling could become issues, which may necessitate pretreatment to reduce dissolved iron and manganese to acceptable concentrations prior to entry into the membrane process. The anoxic nature of the water could complicate the pretreatment process to remove the dissolved metals. Pretreatment requirements could significantly raise the capital and operational costs of SWRO negating the economic advantages of subsurface intakes. Six SWRO cost scenarios were evaluated to assess the impacts of slant wells on capital and operating costs based on the necessary to remove or not remove dissolved iron and manganese. The capital cost comparison of two open-ocean intake pretreatment systems to those in slant wells shows an increase of 6 to 20%. The difference in operating costs can range from 19% lower to 15% higher depending on the pretreatment required.

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“…Studies on TEP distribution in relation to other forms of organic matter in the Red Sea have focused mainly on assessing the links between TEP and phytoplankton and bacterial production (Bar-Zeev et al, 2009b) and the impacts of TEP and dissolved forms of NOM on biofouling in seawater desalination plants (Bar-Zeev et al, 2009a;Dehwah et al, 2015a;Dehwah et al, 2015b;Dehwah et al, 2015c;Dehwah and Missimer, 2016;Rachman et al, 2014;Rachman et Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-59 Manuscript under review for journal Biogeosciences Discussion started: 13 March 2019 c Author(s) 2019. CC BY 4.0 License.…”

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confidence: 99%

Transparent exopolymer particle binding of organic and inorganic particles in the Red Sea: Implications for downward transport of biogenic materials

Dehwah

Anderson

et al. 2019

Preprint

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<p><strong>Abstract.</strong> Binding of particulate and dissolved organic matter in the water column by marine gels allows sinking and cycling of organic matter into deeper water of the Red Sea and other marine water bodies. A series of four offshore profiles were made at which concentrations of bacteria, algae, particulate transparent exopolymer particles (p-TEP), colloidal transparent exopolymer particles (c-TEP), and the fractions of natural organic matter (NOM), including biopolymers, humic substances, low molecular weight neutrals, and low molecular weight acids were measured to depths ranging from 90 to 300&#8201;m. It was found that a statistically-significant relationship occurs between the concentrations of p-TEP and bacteria while a minimal, non-significant relationship between p-TEP and algae occurs. This likely reflects the low abundance of larger algal species in the study region. Variation in the biopolymer fraction of NOM in relationship to TEP and bacteria suggests that extracellular discharges of polysaccharides and proteins from the bacteria and algae are occurring without immediate abiotic assembly into p-TEP. In the water column below the photic zone, TOC, bacteria, and biopolymers show a generally common rate of reduction in concentration, but p-TEP decreases at a diminished rate, showing that it persists in moving organic carbon deeper into the water column despite consumption by bacteria.</p>

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Changes in feedwater organic matter concentrations based on intake type and pretreatment processes at SWRO facilities, Red Sea, Saudi Arabia

Cited by 32 publications

References 17 publications

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination

Aquifer Treatment of Sea Water to Remove Natural Organic Matter Before Desalination

Impacts of natural pore-water and offshore aquifer chemistry on the operation and economics of some subsurface intakes types for SWRO plants

Transparent exopolymer particle binding of organic and inorganic particles in the Red Sea: Implications for downward transport of biogenic materials

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