Water. desalination + reuse

research section 0 1.2 2 1.0 Depth, m 6 0.8 Chl a, mg m-3 AshApr08 AshAug08 AshApr09 VMSep11-Black VMSept11 VMMay11-Black VMMay11 4 8 0.6 0.4 0.2 10 12 39 40 41 0 42 45 Salinity 46 47 0.0 18 48 22 24 26 28 30 Temperature, OC Chl a, mg m-3 6 AshApr08 AshAug08 AshApr09 VMSep11-Black VMSept11 VMMay11-Black VMMay11 8 10 20 22 24 26 28 30 Temperature, OC 32 34 experimental setup Seawater and sediment samples for infauna (sediment dwellers) analysis at Palmachim were collected on board the R/V Etziona during seasonal monitoring cruises at the site. In-situ depth profiles of temperature, salinity, turbidity and dissolved oxygen were measured with a Yellow Spring Instruments YSI 6000 probe or a SeaBird 911 CTD. Seawater for the different analysis was collected with a Flojet pump, and triplicate sediment samples were collected using a Van-veen grab (0.08 m2 area, around 20 L volume) and preserved in 10% formaldehyde. Samples for chlorophyll a (chl-a) and suspended particulate matter (SPM) determination were respectively passed through GF/F filters and preweighted 0.45 ��m Nuclepore membrane filters and frozen. In the laboratory, the SPM filters were dried by lyophylization and reweighed, 34 36 38 0.8 0.6 0.4 0.2 0.0 39 36 Figure 1. Salinity (upper panel) and temperature (lower panel) depth profiles at representative stations at the brine discharge sites at Ashkelon (Ash ��� affected stations) and Palmachim (VM, background (back) and affected stations) quality were described 2, the first report to address this question. In this paper we will describe the marine environment at two contrasting brinedischarge sites: Ashkelon, where the brinecooling water mixture is discharged at the shoreline and disperses at the surface; and Palmachim, where the brine is discharged through a marine outfall and disperses close to the bottom. 32 AshApr08 AshAug08 VMSept08 VMMay09 VMSept10 1.0 4 Depth, m 20 1.2 2 12 AshApr08 Plot 1 Regr AshAug08 Plot 2 Regr VMSept08 VMMay09 VMSept10 40 41 Salinity 42 43 44 Figure 2. Chlorophyll a concentration as a function of temperature (upper panel) and salinity (lower panel) at representative surveys at Ashkelon (Ash) and Palmachim (VM). and the concentration calculated from the difference and the volume filtered. Chl-a was determined fluorometrically after overnight extraction with 95% acetone, in the dark at 4��C 14. The infauna samples were washed with seawater, sieved through 250 micron mesh, preserved with 70% ethanol and and dyed with Rose Bengal. The biota were sorted under a binocular, identified and counted. The experimental set-up at the Ashkelon site was reported by Drami et al (2011) 2. results and discussion Seawater quality Seawater quality at the Ashkelon brinedischarge site was described previously 2, when the backwash of the sand filters, containing iron salt coagulant, was discharged in pulses. The appearance of an unexpected red plume at the outfall site was attributed to the pulsed discharge of ferric hydroxide used as a coagulant in the pretreatment stage. This notable aesthetic effect motivated the regulator 15 to fund the research. Briefly, the mixed brine-cooling waters discharge increased salinity (by up to 1.84) and temperature (by up to 7.8 ��C) at the outfall, compared with ambient values (Figure 1). The mixture was positively buoyant, and dispersed at the surface. Seawater density difference between the upper affected and lower layer ranged from 1.31 to 1.86 sigma T units. There was no effect on dissolved oxygen concentration in seawater. Chlorophyll-a (chl-a) and picophytoplankton cell numbers were negatively correlated with salinity, but more significantly with temperature, probably as a result of thermal pollution (Figure 2). Phytoplankton growth effect The discharge of the pulsed backwash increased turbidity, suspended particulate matter and particulate iron, and decreased phytoplankton growth efficiency at Ashkelon, effects that declined with distance from the outfall. The discharges clearly reduced primary production and affected bacterial production, but this could not be attributed to a specific component of the discharge. Similar increases in salinity and temperature compared with ambient values were measured at the site by the Israel Electric Corporation (IEC), in the framework of environmental monitoring of the power stations 3,16,17. The IEC reports failed to disclose any other effects. Chl-a concentrations were not dependent on temperature or salinity, in contrast to the previous work 2. However, ��� February-March 2012 | Desalination & Water Reuse | 27 |

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