A review on sewage disinfection and need of improvement

摘要

This paper presents a critical review on sewage disinfection process using chlorine, which is shrouded with lot of controversies. The review highlights the general applications and limitations of chlorination of sewage for disinfection including its low efficacy against resistant coliform bacteria that results in excess chlorine dosing. Excessive dose of chlorine is not only expensive, but it can also give rise to a series of DBPs many of which are proven carcinogens. Based on the results of the studies of our research group at MNIT, Jaipur, this paper explores as to how the chlorine doses can be optimized through step dosing and also how can the hybrid method of disinfection optimize the overall cost of desired level of disinfection. Combination of ozone in series with chlorine has been assessed for the possibility of reducing the overall disinfection cost and also at the same time getting rid of some of the carcinogenic DBPs of chlorination.