Year of Publication: 1996
This review assesses the types of inorganic contaminants, the levels of inorganic contaminants, and the potential treatment processes that may be utilized for the removal of inorganic contaminants in the Northern River Basin Study (NRBS) area.
The initial step in this assessment was to compile a list of the inorganic parameters regulated in both the Guidelines for Canadian Drinking Water Quality (GCDWQ) and the World Health Organization (WHO) Drinking Water Quality Guidelines. The inorganics in concern include arsenic, barium, boron, cadmium, chloride, chromium, copper, cyanide, fluoride, iron, lead, manganese, mercury, nitrate, selenium, sodium, sulphate, sulphide, total dissolved solids, uranium, and zinc. In the case of GCDWQ, three criteria have been set for contaminant limits: MAC (maximum acceptable concentration), IMAC (interim maximum acceptable concentration), and AO (aesthetic objective).
In order to assess the importance of these inorganic contaminants with particular relevance to the NRBS area, the next step in this review was to summarize the results of the inorganic data compiled by Prince et al (1995) in a prior study of drinking water quality in the study area. By comparing the reported levels with the guideline values from the CGDWQ and the WHO, it can be seen that in terms of inorganic contaminants, drinking water quality in the NRBS area is generally of good quality. With the exception of turbidity, the upper 95% confidence level concentrations were all below the health related guidelines. However, the aesthetic parameters were exceeded for total dissolved solids, iron, manganese, and sodium that might cause some taste / odor problems.
The final aspect of analysis of inorganic contaminants in NRBS area was to present possible treatment methods for the reduction of given contaminants. Each inorganic contaminant was listed with the recommended treatment options, as well as the effects that conventional and advanced treatment processes have on given inorganics. It was found that not all inorganics could effectively be removed using conventional treatment processes. Cost factors should be considered when using advanced treatment processes. It is also important to note that an individual treatment method may be successful for the reduction of a certain type of inorganic, but it may contribute to the levels of other inorganics. Therefore, it is important that all types of contaminants are considered when making decisions on water treatment. Typically, a detailed analysis is required to consider site specific information. As is often the case in water treatment design and assessment, pilot and bench testing is required prior to implementing any significant changes.