Effect of biofilms grown at various chloramine residuals on chloramine decay

Abstract

Maintaining longer lasting disinfectant residual in a distribution system is highly important to prevent microbial re-growth and hence to deliver safe drinking water. However, various factors such as microbes present in bulk water, sediment, or attached to pipe wall and biofilms accelerates the chloramine decay. Among them, biofilms are a major factor in accelerating chloramine decay as they provide a habitat for the microbes. Thus, this study investigates the effect of biofilms in terms of chloramine decay in the distribution system. Biofilms were grown under various chloramine residuals and different ages of biofilms were investigated by subjecting them to batch tests. Experimental results repeatedly showed that chloramine decay due to biofilms is independent of its growth condition, particularly for different chloramine residuals.

Zwitterionic poly(sulfobetaine methacrylate)-based hydrogel coating for drinking water distribution systems to inhibit adhesion of waterborne bacteria

“…Biofilms are microbial communities consisting of cells embedded in extracellular polymeric substances that can form on any surface ( Flemming et al, 2016 ). Their development in DWDS can lead to operational issues, such as increased secondary disinfectants demand ( Adhikari et al, 2012 ), pipe damage through microbially induced corrosion of iron-based pipework ( Wang et al, 2015 ), or increased flow resistance ( Cowle et al, 2014 ). Additionally, the detachment of biofilm clusters can directly affect water quality by not only worsening its aesthetics (turbidity, color, smell) ( Husband and Boxall, 2011 ), but also posing as a health hazard as biofilms can serve as a potential pathogen reservoir ( Wingender and Flemming, 2011 ).…”

Assessing biofilm development in drinking water distribution systems by Machine Learning methods

“…The limited penetration of chlorine into biofilm is not only due to a transient diffusion, but it is also caused by the neutralization of chlorine in the biofilm matrix [89]. Similarly, chloramine decay in a distribution system accelerates with the presence of biofilms and sediments [90]. It has also been observed that, under comparable conditions, there is a variability in the chlorine penetration rate into the biofilm.…”