Characterization of Disinfection By-Products Levels at an Emergency Surface Water Treatment Plant in a Refugee Settlement in Northern Uganda

Abstract

The reliance on chlorination in humanitarian operations has raised concerns among practitioners about possible health risks associated with disinfection by-products; however, to date, there has not been an evaluation of disinfection by-product (DBP) levels in an emergency water supply intervention. This study aimed to investigate DBP levels at a surface-water treatment plant serving a refugee settlement in northern Uganda using the colorimetric Hach THM Plus Method. The plant had two treatment processes: (1) Simultaneous clarification–chlorination (“rapid treatment”); and (2) pre-clarification and chlorination in separate tanks (“standard treatment”). For both standard (n = 17) and rapid (n = 3) treatment processes, DBP levels in unique parcels of water were tested at 30 min post-chlorination and after 24 h of storage (to simulate what refugees actually consume). DBP levels after 24 h did not exceed the World Health Organization (WHO) guideline limit of 300 ppb equivalent chloroform, either for standard treatment (mean: 85.1 ppb; 95% confidence interval (C.I.): 71.0–99.1 ppb; maximum: 133.7 ppb) or for rapid treatment (mean: 218.0 ppb; 95% C.I.: 151.2–284.8; maximum: 249.0 ppb). Observed DBPs levels do not appear to be problematic with respect to the general population, but may pose sub-chronic exposure risks to specifically vulnerable populations that warrant further investigation.

Disinfection Byproducts in Intermittent Piped Water Supplies

“…Discontinuous or irregular monitoring in IWS systems may provide an incomplete understanding of the risks of DBPs in these systems due to their complex hydraulics and different supply stages. Although some studies have used portable testing kits for the measurement of TTHM, these methods are not generally approved for regulatory purposes and are limited in scope (e.g., measure only certain DBP classes and high detection limits). , Research on and monitoring of DBPs in low-resource settings with IWS would benefit greatly from newer methods for detecting and quantifying DBPs under field conditions or to accommodate limited laboratory capacities.…”

Public Water Supply and Sanitation Authorities for Strategic Sustainable Domestic Water Management. A Case of Iringa Region In Tanzania

“…Even in advanced treatment practices that involve turbid water clarification prior to chlorination, organic flocculant residuals play a vital role in the formation of DPBs [78]. However, with such an observation, many remediation approaches are suggested for combating DBP issues: membrane technique is an excellent [79], two-stage or standard treatment, contrasted by rapid [80] in WSSA implementing clarification processes that reduce DBP levels. However, the common and affordable method is household boiling of treated water meant for drinking (Table 2).…”

Public Water Supply and Sanitation Authorities: A Sustainable Domestic Water Management Strategy in Tanzania

“…membrane technique being excellent [88], two stage or standard treatment as contrasted from rapid [2] in WSSA implementing clarification processes reduces DBPs levels, but the common and affordable one being household boiling of such treated water meant for drinking. Generally, Table 4 shows that rural water supplies are very expensive compared to urban-based people at an affordable cost, the opposite is observed due to most points having higher or comparable cost with those of private based.…”