Growth Characteristics of Biofilms in Greywater

As the demand for water continues to be an issue, methods to improve the efficiency of water consumption are of interest. Use of greywater systems can be a low cost way to recycle water, reducing the overall water demand. One major problem related to greywater is the formation of biofilms, which can quickly compromise a system by increasing the bacterial load and clogging pipes. Washing machine water during the wash cycle was used as a greywater and microbe source for these experiments which determined various biofilm size factors including; storage material, incubation time, and cell density. Additionally biofilm removal by sonication was examined. Samples were stained with crystal violet, eluted in ethanol, and measured with spectroscopy to determine relative biofilm size. It was found that biofilms grew better on hydrophilic surfaces, younger samples grew faster, higher cell densities lead to larger biofilms, and sonication decreased the biofilm size. These findings support the original concern of biofilms forming in greywater, and provided a possible solution to the biofilm formation.