Microbiological assessment of biofilm formation on different water storage containers

Abstract

Providing safe drinking-water, especially to those in developing countries, is still a major problem. These problems are divers and serious. Worst still, is the issue of scarcity, which has encouraged water storage in containers for future use. Long period of storage may lead to the formation of biofilms. This study aims to monitor the formation of biofilms in different water storage containers, using viable and total coliform counts as indicators, carry out isolation and characterization of organism that may possibly be responsible for the biofilm formation. Water storage containers used include polyethylene, plastic, glass, rubber, galvanized steel, aluminium, stainless steel and clay. Weekly sampling and analysis were performed by measuring pH, viable and total coliform counts using plate count and Most Probable Number technique while the biofilm formed in each container was weighed. The results showed that polyethylene had the highest degree of biofilm formation weighing 0.090 g while galvanized and stainless steel had the lowest level of biofilm formation weighing 0.010 g. Statistically, there was a difference between polyethylene and galvanized steel and aluminium and stainless steel as their p-values were less than 0.05. There was no statistical difference between glass and plastic and between plastic and rubber. Pseudomonas aeruginosa was identified as the biofilm forming organism in the different water storage containers. The findings strengthen evidence that pathogenic bacteria entering or already present in water storage systems can survive in biofilms for at least several weeks, even under unfavourable conditions, and may be a risk to consumers of such water.