Disinfection of Water by N-Halamine Biocidal Polymers

N-chlorinated (Poly-I) and N-brominated (Poly-IB) derivatives of a polystyrene hydantoin were evaluated for their performance as filters for pumped aqueous solutions of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans with a contact period of the order of 1-2 seconds per ml. The investigation covered parameters such as pH, temperature, flow rate and dilution with inert sand. Small quantities of Poly-I and Poly-IB were effective at inactivating a range of micro-organisms, when used in a filter application. The 2 materials functioned adequately over the 4.5-9.5 pH range and at temperatures between 4C and 37C. Poly-IB appeared to be more effective than Poly-I, probably due to the fact that bromamines and free bromine are more biocidal than their chlorine counterparts. A feature of these polymers was that they could be regenerated by the use of rechlorination or rebromination.