Peritoneal dialysis effluent as a non-potable water resource: Biochemical and microbiological characterization compared to treated wastewater

Abstract

Background

The global water crisis poses challenges for water-intensive sectors, such as healthcare. In Mexico, continuous ambulatory peritoneal dialysis (CAPD) is used by almost half of patients on renal replacement therapy, generating significant volumes of peritoneal dialysis effluent (PDE) that are discarded without reuse. Unlike haemodialysis effluents, whose reuse has already been demonstrated, PDE lacks technical evidence regarding its biochemical and microbiological safety for potential non-potable applications. The objective of this study was to biochemically and microbiologically characterise the PDE generated by patients with chronic kidney disease in CAPD, comparing them with treated wastewater (TWW) and analysing their potential for non-potable reuse.

Methods

PDEs obtained from CAPD patients were studied and compared with 18 TWW samples from urban and industrial plants. Biochemical parameters (glucose, creatinine, urea, uric acid, electrolytes, pH, and residual chlorine) and microbiological parameters (mesophilic bacteria, gram negative, gram positive, coliforms, and fungi) were analysed using automated methods and classical culture, respectively. Student's t test (p < 0.05) was used to determine significant differences between groups.

Results

The PDE showed significantly higher concentrations of glucose (>750 mg/dL), urea, creatinine, and electrolytes compared to TWW (p < 0.0001), reflecting its hyperosmolar nature. The pH was neutral (∼7) and there was no residual chlorine. The complete absence of cultivable microbiological load in PDE was highlighted, unlike TWW, which presented significant elevated bacterial and fungal counts. These findings suggest a favourable microbiological profile of PDE, but a limiting biochemical load for its direct reuse.

Conclusion

PDE has potential for non-potable reuse, especially in agricultural or industrial applications, but requires advanced treatment such as reverse osmosis, nanofiltration, ultrafiltration, among others, to remove its high solute load. It is essential to create a specific regulatory framework for the reuse of this type of effluent, provided its safety is guaranteed.