Jerricans are commonly used to store household drinking water. However, biofilms can grow on jerrican surfaces and contaminate water. To investigate mechanisms to inhibit biofilm growth, 72 5 L jerricans containing E. coli-spiked water were incubated for 10 weeks in the laboratory. Jerricans were stratified by: water treatment with chlorine; turbidity; and, regular cleaning with NaOCl, rocks, sand, NaOCl/rocks, and NaOCl/sand. At study end, surface E. coli was enumerated and biofilms imaged using epifluorescence microscopy; free chlorine residual was tested regularly. We found biofilms grew rapidly in jerricans (presence confirmed in 3 weeks), and chlorine demand within jerricans increased over time as FCR decreased from 1.16 to 0.59 mg L-1 over the course of the study in 5 NTU treated waters. Biofilm growth was significantly inhibited by water treatment with chlorine (p = 0.03), and was inhibited by cleaning with NaOCl or NaOCl/rocks. Cleaning with rocks increased surface roughness, which promotes biofilm growth. These results highlight the need for research on locally-appropriate cleaning methods and/or alternatives (e.g. replacement, biofilm-resistant surfaces) to ensure jerricans provide safe storage of drinking water.
Efficacy of locally-available cleaning methods and household chlorination at inhibiting biofilm development in jerricans used to store household drinking water
Domini M.;Lantagne D. S.
2021-01-01
Abstract
Jerricans are commonly used to store household drinking water. However, biofilms can grow on jerrican surfaces and contaminate water. To investigate mechanisms to inhibit biofilm growth, 72 5 L jerricans containing E. coli-spiked water were incubated for 10 weeks in the laboratory. Jerricans were stratified by: water treatment with chlorine; turbidity; and, regular cleaning with NaOCl, rocks, sand, NaOCl/rocks, and NaOCl/sand. At study end, surface E. coli was enumerated and biofilms imaged using epifluorescence microscopy; free chlorine residual was tested regularly. We found biofilms grew rapidly in jerricans (presence confirmed in 3 weeks), and chlorine demand within jerricans increased over time as FCR decreased from 1.16 to 0.59 mg L-1 over the course of the study in 5 NTU treated waters. Biofilm growth was significantly inhibited by water treatment with chlorine (p = 0.03), and was inhibited by cleaning with NaOCl or NaOCl/rocks. Cleaning with rocks increased surface roughness, which promotes biofilm growth. These results highlight the need for research on locally-appropriate cleaning methods and/or alternatives (e.g. replacement, biofilm-resistant surfaces) to ensure jerricans provide safe storage of drinking water.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.