Tag Archives: desalination

Lower Magnesium Intake from Desalinated Seawater Associated with Cardiovascular Effects

Shlezinger M, Amitai Y, Goldenberg I, Shechter M. Desalinated seawater supply and all-cause mortality in hospitalized acute myocardial infarction patients from the Acute Coronary Syndrome Israeli Survey 2002-2013. International Journal of Cardiology. 2016 Jun 29;220:544-550. doi: 10.1016/j.ijcard.2016.06.241.

BACKGROUND: Consuming desalinated seawater (DSW) as drinking water (DW) may reduce magnesium in water intake causing hypomagnesemia and adverse cardiovascular effects.

METHODS: We evaluated 30-day and 1-year all-cause mortality of acute myocardial infarction (AMI) patients enrolled in the biannual Acute Coronary Syndrome Israeli Survey (ACSIS) during 2002-2013. Patients (n=4678) were divided into 2 groups: those living in regions supplied by DSW (n=1600, 34.2%) and non-DSW (n=3078, 65.8%). Data were compared between an early period [2002-2006 surveys (n=2531) – before desalination] and a late period [2008-2013 surveys (n=2147) – during desalination].

RESULTS: Thirty-day all-cause-mortality was significantly higher in the late period in patients from the DSW regions compared with those from the non-DSW regions (HR=2.35 CI 95% 1.33-4.15, P<0.001) while in the early period there was no significant difference (HR=1.37 CI 95% 0.9-2, P=0.14). Likewise, there was a significantly higher 1-year all-cause mortality in the late period in patients from DSW regions compared with those from the non-DSW regions (HR=1.87 CI 95% 1.32-2.63, P<0.0001), while in the early period there was no significant difference (HR=1.17 CI 95% 0.9-1.5, P=0.22). Admission serum magnesium level (M±SD) in the DSW regions (n=130) was 1.94±0.24mg/dL compared with 2.08±0.27 mg/dL in 81 patients in the non-DSW (P<0.0001).

CONCLUSIONS: Higher 30-day and 1-year all-cause mortality in AMI patients, found in the DSW regions may be attributed to reduced magnesium intake secondary to DSW consumption.

Is Complete Demineralization of Drinking Water Desirable?

Verma KC, Kushwaha AS. Demineralization of drinking water: Is it prudent? Medical journal, Armed Forces India. 2014 Oct;70(4):377-9. doi: 10.1016/j.mjafi.2013.11.011.

Water is the elixir of life. The requirement of water for very existence of life and preservation of health has driven man to devise methods for maintaining its purity and wholesomeness. The water can get contaminated, polluted and become a potential hazard to human health. Water in its purest form devoid of natural minerals can also be the other end of spectrum where health could be adversely affected. Limited availability of fresh water and increased requirements has led to an increased usage of personal, domestic and commercial methods of purification of water. Desalination of saline water where fresh water is in limited supply has led to development of the latest technology of reverse osmosis but is it going to be safe to use such demineralized water over a long duration needs to be debated and discussed.

Click here for paper (Open Access).

Water quality impacts reverse osmosis biofouling in desalination

Siqian Huanga, Nikolay Voutchkovb, Sunny C. Jianga. Investigation of environmental influences on membrane biofouling in a Southern California desalination pilot plant. Desalination, Volume 319, 14 June 2013, Pages 1–9.
http://dx.doi.org/10.1016/j.desal.2013.03.016

One of the challenges the seawater desalination industry faces today is reverse osmosis (RO) membrane biofouling. Traditional water quality parameters such as SDI and the RO feed water turbidity are inadequate at protecting the membrane from biofouling. This research investigated the environmental and water quality parameters in a Southern California desalination plant in order to develop a set of seawater desalination RO membrane biofouling indicators. Statistical analysis was performed on data collected onsite over two years. The relationships between operation parameters, rain precipitations, TOC, UV254, chlorophyll fluorescence in raw seawater and the performance loss of the RO desalination process are presented. The environmental triggers for accelerated RO membrane biofouling was further investigated by developing membrane fouling simulators at the desalination pilot plant. Biofouling was confirmed by confocal laser scanning microscopy investigation of membrane biofilm and live and dead bacterial cell counts. The results of this study indicated that biofouling was significantly correlated with water quality changes. Thus, chlorophyll fluorescence measurements can be used as a precursor for desalination membrane biofouling.

Click here for full paper (fee).

Dissolved solids in Southwestern US water resources

Anning DW. Modeled Sources, Transport, and Accumulation of Dissolved Solids in Water Resources of the Southwestern United States. J Am Water Resour Assoc. 2011 Oct;47(5):1087-1109.

jawr0047-1087-f1

Information on important source areas for dissolved solids in streams of the southwestern United States, the relative share of deliveries of dissolved solids to streams from natural and human sources, and the potential for salt accumulation in soil or groundwater was developed using a SPAtially Referenced Regressions On Watershed attributes model. Predicted area-normalized reach-catchment delivery rates of dissolved solids to streams ranged from <10 (kg/year)/km(2) for catchments with little or no natural or human-related solute sources in them to 563,000 (kg/year)/km(2) for catchments that were almost entirely cultivated land. For the region as a whole, geologic units contributed 44% of the dissolved-solids deliveries to streams and the remaining 56% of the deliveries came from the release of solutes through irrigation of cultivated and pasture lands, which comprise only 2.5% of the land area. Dissolved-solids accumulation is manifested as precipitated salts in the soil or underlying sediments, and (or) dissolved salts in soil-pore or sediment-pore water, or groundwater, and therefore represents a potential for aquifer contamination. Accumulation rates were <10,000 (kg/year)/km(2) for many hydrologic accounting units (large river basins), but were more than 40,000 (kg/year)/km(2) for the Middle Gila, Lower Gila-Agua Fria, Lower Gila, Lower Bear, Great Salt Lake accounting units, and 247,000 (kg/year)/km(2) for the Salton Sea accounting unit.

Click here for the full paper (Open Source).

Solar and wind aided evaporation of RO reject water

Ligy Philip, K.S. Reddy, Bhuvanesh Kumar, S. Murty Bhallamudi, A. Kannan. Performance evaluation of a solar and wind aided cross-flow evaporator for RO reject management. Desalination 317 (2013) 1–10.

In the present study, an attempt was made to evaluate the performance of a solar and wind aided cross-flow evaporator prototype as an alternative to conventional evaporators for concentrating reverse osmosis (RO) rejects. The performance of the solar andwind aided cross-flowevaporatorwas evaluated for different operating conditions such as (i)wind velocity, (ii) relative humidity in the ambient air, (iii) temperature of inletwater, (iv) trickling rate and (v) different packing geometries. Empirical correlations for evaporation loss were developed, as a function of the above variables. Among the various synthetic and natural media tried, plastic flexi ring was the most effective. Solar and wind aided cross-flow evaporator with random packing performed better than that with structured packing, as long as the air flow is not blocked by the packing. Studies revealed that the exposed surface area and depth of packing in the direction of wind are the important dimensions of the natural evaporator. Itwas also found that solar pre heating significantly increased the evaporation rate. Evaporation rate decreased as the concentration of salt in the water increased.

Click here for full article (Open Source).

San Diego, CA approves 30-year purchase agreement for desalinated water

“The San Diego County Water Authority Board of Directors overwhelmingly approved  a 30-year deal Thursday to take desalinated water from a future plant in  Carlsbad.”

“The water authority board voted in favor of the purchase agreement by margin  of 85 percent to 10 percent, with the rest abstaining. The vote clears the way  for the $1 billion desalination plant next to the Encina Power Station.”

Click here for the news article….

First Ghana (Africa) desalination plant under construction

The desalination plant, which will require an investment of US$ 125 million, will have the capacity to produce 60,000 m3/day using reverse osmosis technology.

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