Artificial sweeteners (or sugar substitute) are synthetic compounds that acts as food additive which duplicate/increase the effect of sugar in taste. They actually increase the sweetness from hundreds to thousand fold compared to sugar that attracts investors because it is cost effective.
Consequently, the usage of artificial sweeteners prose an issue regarding its impact on the environment. If an artificial sweetener is sent to waste water, bacteria can consume it thus producing toxic substances that can affect the living organisms. There are studies that have been found out that a certain bacteria can digest sucralose and in turn increasing the chlorine content of the wastewater. Right now, artificial sweeteners are not significantly harmful but if the concentration increases by time, the effect could dramatically increase as well.