Chemical disinfection has been for the last 100 years, an integral part of municipal drinking water treatment, in order to achieve the protection of public health. Some time ago, the addition of disinfectant was just as much as required to remove all the microorganisms. Further experience has shown that it is not that simple, due to the disinfection byproducts (DBPs) that appear during this process, which can significantly affect the consumer health.
In order to deal with the DBPs, the main health organizations and governments have introduced pretty restrictive limits that must be achieved in order to guarantee the supply of safe drinking water. There are several ways to achieve the required thresholds, because of the chemistry of formation of the byproducts. Taking a look in the next expression, the different ways of reducing them can be easily seen:
Natural Organic Matter + disinfectant ----- disinfection byproducts
In order to reduce the disinfection byproducts, while keeping a good water quality, the removal of natural organic matter (NOM) is the key factor. NOM is present in almost all sources of water all around the world, and is a mixture of several organic compounds. It is considered harmless, but due to its reaction with the disinfectant its removal has been deeply studied.
When the NOM is removed, a removal of the colour, ultraviolet absorbance at 254 nm (UV-254) and some other are also expected. This means that the reduction of the NOM will be achieved with the same methods that traditionally have been used to remove these parameters.
In this study, the methods that have been analyzed are: 1) chemical coagulation and precipitation; 2) adsorption on activated carbon and 3) magnetic ion exchange. The first one, has been deeply studied for many years, and is a well known and popular method. The next two, because of having appeared more recently, still need to be studied.
The aim of this project is to investigate these treatment options for water containing elevated levels of NOM, and then enhance its removal by optimizing the proposed processes as a single unit, to obtain the proper operation conditions, as well as assessing the combination of the proposed optimized processes, with the monitoring of the bulk parameters and the molecular weight range removal.
