Design and technical adjustment of a water treatment system: 15 years of experience

Association of the efficiency of hemodialysis instruments in the removal of microbial and chemical pollutant

Dialysis water is vital because of various harmful contaminants for patients. The aim of this study was to assess the efficiency of hemodialysis instruments in the removal of microbial and chemical pollutant in educational hospitals affiliated to Ahvaz Jundishapur University of medical sciences, Iran during 2018-2019. This cross-sectional descriptive research studied the microbial and chemical water quality of hemodialysis instruments in Razi, Sina, and Golestan hospitals in Ahwaz, Iran. 72 samples of microbial parameters and 24 samples of chemical parameters were collected from water used in hemodialysis instruments, including microbial characteristics (the total coliform, fecal coliform and heterotrophic bacteria counts) and chemical characteristics (pH, turbidity, PO₄, Cl, Mg, So₄, Ca, NO₂, and EC) at Razi, Imam, and Golestan educational hospitals on all weekdays during 2018-2019. In this study, experiments were done according to the current standard methods, EPA from hemodialysis instruments. Finally, using SPSS18 software and descriptive statistics, the relationship between results at the removal of toxic, microbial, and chemical pollutants in different months and hospitals was investigated. this study showed that the average concentration of chemical characteristics during the warm season at Razi, Imam, and Golestan educational hospitals for pH, Turbidity, PO₄, Cl, Mg, So₄, Ca, NO₂, and EC were (6.867, 6.4475, 6.53); (2.985, 3.035, 1.226); (0.075, 0.245, 0.195); (38.5, 21.965, 144.87); (1.552, 1.657, 39.445); (8.6, 4.5, 21.5), (2.09, 3.187, 78.975); (0.0082, 0.038, 0.155), and (125.25, 70.35, 78.35), respectively during 2018. Also, during 2019, results showed that the average levels of amounts for pH, Turbidity, PO₄, Cl, Mg, So₄, Ca, NO₂, and EC in Razi, Imam, and Golestan educational hospitals were (7.077, 7.252, 6.435), (1.725, 0.595, 4.16), (0.0775, 0.0597, 0.0297), (52.33, 138.81, 20.92), (23.52, 18.227, 8.767), (35, 27.25, 4.05), (14.58, 28.152, 9.25), (0.0067, 0.0045, 0.0032), and (210.52, 121.62, 29.16), respectively. According to the results, hemodialysis instruments in Razi and Imam have a 90% efficiency in removing heterotrophic bacteria counts (HPC). Based on these findings, educational hospital hemodialysis equipment effluent in Ahvaz, Iran was mitted to Iran environmental standards for use in hemodialysis machines. The result showed that the removal percentage level of microbial and chemical pollutants by the hemodialysis process is comparatively suitable. It should be mentioned that in the proper operation and reconstruction, hemodialysis systems can have an increased rate of removal of microbial and chemical pollutants.

The evolution of technological strategies in the prevention of dialysis water pollution: sixteen years' experience

AIM

This report attempts to illustrate the positive impact on the quality of dialysis water produced over a 16-year period through the progressive optimization of technological procedures.

METHODS

Fundamental steps included the following: elimination of polyvinyl chloride (PVC), periodical controls, introduction of stainless steel and/or polyethylene polymer and substitution of single-pass reverse osmosis (SRO) with double-pass reverse osmosis (DRO). Daily overnight automatic thermal disinfection of distribution piping rings represented the final step.

RESULTS

A dramatic improvement was observed in 645 water samples obtained from distribution piping. The measures applied resulted in a significant improvement of water quality, featuring levels of colony-forming units per milliliter ranging from 247.4 ± 393.7 in the presence of PVC and SRO to 14.1 ± 28.0 with stainless steel and DRO and 2.8 ± 3.2 with cross-linked polyethylene thermoplastic polymer and DRO (p < 0.01).

CONCLUSIONS

Dialysis water should be viewed by nephrologists as a medicinal product, and every effort should be made to ensure a high-quality liquid.

Dialysis water as a determinant of the adequacy of dialysis

Hemodialysis patients are exposed to large volumes of water in the form of dialysate. Contaminants from the dialysate may cross the dialyzer membrane into the blood and have the potential to compromise the adequacy of dialysis. Several chemicals found commonly in drinking water have long been known to be toxic to hemodialysis patients. More recently, it has become apparent that even low levels of bacterial products in dialysate may adversely impact dialysis adequacy through their ability to stimulate an inflammatory response. Minimum levels of water and dialysate quality have been recommended to protect patients from chemical and microbiologic contaminants. Complying with these recommendations requires an appropriately designed water purification and distribution system, combined with a surveillance program designed to maintain dialysate quality.

POOR NUTRITIONAL STATUS AND INFLAMMATION: Ultrapure Dialysate

To prevent pyrogenic reactions during hemodialysis, it is recommended that bacteria and endotoxin in dialysate not exceed 100-200 colony forming units (CFU)/ml and 0.25-2 endotoxin units (EU)/ml, respectively. While these limits are adequate to prevent acute pyrogenic reactions, data are accumulating to suggest they may not prevent stimulation of chronic inflammation in hemodialysis patients. Fragments of endotoxin and other bacterial products capable of stimulating immune cells cross low-flux and high-flux membranes in vitro. In clinical studies, use of ultrapure dialysate (bacteria < 0.1 CFU/ml and endotoxin < 0.03 EU/ml) is associated with lower concentrations of inflammatory markers and acute phase reactants than are observed with dialysate meeting current quality recommendations. Moreover, observational studies suggest a link between clinical outcomes and dialysate purity. Treatment of patients with ultrapure dialysate is reported to improve nutritional status, increase responsiveness to erythropoietin, slow the decline in residual renal function, lessen cardiovascular morbidity, and decrease the incidence of beta(2)-microglobulin amyloidosis. To date, however, none of these studies has shown a cause-and-effect relationship between dialysate purity and outcome. Further, there are no data defining the concentration dependence of outcomes on dialysate purity and the relative importance of dialysate purity as a trigger of inflammation remains unclear. While the technology exists to routinely provide ultrapure dialysate, controlled clinical trials are still needed to answer the question of whether or not introducing ultrapure dialysate into routine clinical practice represents an efficient use of limited resources in terms of decreasing inflammation and improving outcomes in hemodialysis patients.