**4. Conclusions**

The objective of this document was to carry out a methodological analysis of the technologies available for the removal of sulfur in water for human consumption. This review provides a guideline to possible users or possible research in the area of sulfate removal. A user, based on the characteristics of the water, concentration, pH, T, can choose a method that is fit for a given application, considering the available resources (monetary, human, space), and characteristics of the water to be treated

Given the complexity and diversity of the technologies and materials evaluated, choosing the best methodology or material depends on several factors, including equipment availability, technology, operation, maintenance, economy, response speed, efficiency. These factors become more relevant for developing countries like Mexico, where there is a lack of trained technicians, or places with the greatest need for water have limited or no access to replacement parts.

All necessary pretreatment, pH change, use of reagents before or after treatment, installation or initial investment, operation, and maintenance requirements, must be considered when evaluating which methodology is better, especially if there are economic restrictions. When considering biological treatment, it is important to keep in mind the high retention times needed for relevant removal efficiencies. Finally, it is also important to keep in mind that a 98% efficiency removal with a sample below 66 mg L−1 (as is the case of Adsorption Polyaniline) is not the same as a 90% efficiency with concentrations of 3,665 mg L−1 (as in the case of ion exchange).

This review also helps identify the following research gaps and opportunities:


Sulfur water has not been considered for human consumption due to social rejection caused by the characteristic taste and smell of sulfur present in the water. However, this water has the potential to become an important source of drinking water after treatment. This review provides the basis to identify technologies that can be effective at removing sulfate from potential drinking water sources. In particular, for countries like Mexico, there is still room for improvement in developing a methodology that is effective and economic, and that can be used at a large scale in water purification plants. Currently, the best options are physical treatments, such as the use of membranes or adsorbents, but other materials or a combination of them could provide better alternatives.
