Improving Desalination Recovery Using Zero Discharge Desalination (ZDD): A Process Model for Evaluating Technical Feasibility

Zero Discharge Desalination (ZDD) is a very-high-recovery hybrid desalination system, typically comprised of a primary desalter (such as reverse osmosis (RO) or nanofiltration (NF)) and electrodialysis metathesis (EDM). The EDM acts as a “kidney” by removing troublesome salts from the concentrate of the primary desalter, which allows for additional recovery of potable water. A mathematical model was developed to simulate ZDD system performance using mass balance, desalination design equations, and experimental data. Model results confirm that ZDD can achieve >97% system recovery for brackish water with (a) a feed total dissolved solids (TDS) concentration of <3 g/L; (b) relatively high fractions of multivalent ions (e.g., calcium and sulfate mass concentrations of >60% of the TDS); and (c) a silica content of <40 mg/L. Furthermore, model results indicate that the required ZDD specific energy consumption (a) increases by 0.77 kWh per 1 g/L of feed TDS; (b) increases with lower permeate TDS, especially below 500 mg/L; and (c) generally decreases with higher recovery on the primary desalter (e.g., RO or NF). ZDD system recovery generally decreases by ∼1% per 1 g/L of feed TDS. Higher TDS feedwater (e.g., 3.5 to 5 g/L) limits ZDD system recoveries to 94% to 90%, respectively

RT-PCR targets with primer and probe sequences.

<p>RT-PCR targets with primer and probe sequences.</p

Peripheral neutrophil counts during hemorrhage and reperfusion periods.

<p>Dashed line indicates end of hemorrhage and beginning of reperfusion period. Data is depicted as mean ± SEM.</p

Central lymphocyte counts at time of necropsy.

<p><b>a</b>) Representative immunohistochemistry pictures (20× magnification) of anti-CD3 staining of normal, control, and FTY720 mesenteric lymph node and spleen tissue. <b>b</b>) Quantification of anti-CD3 reactivity by ACIS. * indicates p<0.05 compared to normal, unmanipulated tissue; † indicates p<0.05 compared to control. Data is depicted as mean ± SEM.</p

Peripheral leukocyte counts during hemorrhage and reperfusion periods.

<p>Dashed line indicates end of hemorrhage and beginning of reperfusion period. Leukocytes were significantly decreased during the reperfusion period in the FTY720 group (p = 0.03). Data is depicted as mean ± SEM.</p

Hemodynamic profiles during hemorrhage period for FTY720 and vehicle control (in this and subsequent figures control is used for vehicle control) groups.

<p><b>a</b>) Heart rate. <b>b</b>) Mean arterial pressure. <b>c</b>) Cardiac output. There were no statistical differences between the control and experimental hemodynamic profiles.</p

Experimental design.

<p>Liver injury was initiated at t = 0. Uncontrolled hemorrhage occurred until 1 hour, at which time the abdomen was packed and temporarily closed (pre-hospital phase). The animal was observed until 2 hours when hospital care was initiated. The liver was repaired and the abdomen definitively closed. The animal was then observed for a total of 72 hours. Blood transfusion was administered as indicated. Necropsy was performed when the animal expired or at 72 hours following euthanasia. The uncontrolled hemorrhage and pre-hospital phases were considered the hemorrhage period, while the hospital care phase was considered the reperfusion period. In the experimental group, FTY720 (0.3 mg/kg diluted in 250 mL of NS)) was administered 15 minutes following liver injury. Vehicle controls were treated with 250 mL of NS.</p

Inflammatory gene transcript expression in liver tissue of FTY720 relative to the control group.

<p>Mean value of relative fold expression is depicted on a logarithmic scale. * indicates p<0.05 compared to control group.</p

Characterization of Cells Isolated from Genetic and Trauma-Induced Heterotopic Ossification

<div><p>Heterotopic ossification (HO) is the pathologic formation of bone separate from the normal skeleton. Although several models exist for studying HO, an understanding of the common <i>in vitro</i> properties of cells isolated from these models is lacking. We studied three separate animal models of HO including two models of trauma-induced HO and one model of genetic HO, and human HO specimens, to characterize the properties of cells derived from tissue containing pre-and mature ectopic bone in relation to analogous mesenchymal cell populations or osteoblasts obtained from normal muscle tissue. We found that when cultured <i>in vitro</i>, cells isolated from the trauma sites in two distinct models exhibited increased osteogenic differentiation when compared to cells isolated from uninjured controls. Furthermore, osteoblasts isolated from heterotopic bone in a genetic model of HO also exhibited increased osteogenic differentiation when compared with normal osteoblasts. Finally, osteoblasts derived from mature heterotopic bone obtained from human patients exhibited increased osteogenic differentiation when compared with normal bone from the same patients. These findings demonstrate that across models, cells derived from tissues forming heterotopic ossification exhibit increased osteogenic differentiation when compared with either normal tissues or osteoblasts. These cell types can be used in the future for <i>in vitro</i> investigations for drug screening purposes.</p></div

Characterization of <i>in vitro</i> osteogenic differentiation of muscle-derived MSC isolated from a rat blast/polytraumatic extremity injury model of HO.

<p>(A) MSCs were harvested and cultured from the soft tissue about the injury site in a rat blast/ polytraumatic extremity injury model. MSCs harvested from the blast injury/amputation site (Injured) 5 days after injury showed more ALP activity and more in vitro bone deposition by Alizarin red staining than cells derived from the same site on the contralateral, un-injured limb (Control). Representative wells and 10x micrographs are shown. (B) Expression levels of <i>Opn</i>, <i>Osx</i>, and <i>Runx2</i>. (C) Western blot analysis of pSmad 1/5 protein levels in these cells after 0, 6, and 18 days in osteogenic media. Data shown are reported as the mean ± SD of at least three separate experimental samples performed in triplicate. *<i>p</i><0.05; **<i>p</i><0.01. Student T-test.</p