HRC is supplied as a viscous liquid for direct injection into contaminated groundwater and saturated soils. This specially formulated product produces a controlled release of lactic acid upon contact with water (Figure 1). This newly available source of lactic acid is then metabolized by microbes to produce hydrogen which is then used in a naturally occurring process known as anaerobic reductive dechlorination (Figure 2). The reductive dechlorination process results in the step-by-step biological degradation of chlorinated contaminants. HRC can be used to degrade a range of chlorinated compounds including: degreasing agents (PCE, TCE, TCA and their breakdown products), carbon tetrachloride, chloroform, methylene chloride, certain pesticides/herbicides, perchlorate, nitrate, nitroaromatic explosives and dyes, chlorofluorocarbons, certain metals and radionuclides.

As discussed, reductive dechlorination is a term used to describe the mechanism by which chlorinated hydrocarbons are biologically degraded under anaerobic conditions. In this natural process, anaerobic microbes substitute hydrogen (H) for chlorine (Cl) on chlorinated contaminant molecules, thus dechlorinating the compound. Being a natural process, reductive dechlorination usually proceeds at very slow, unsustainable rates. HRC increases the rate of dechlorination up to several orders of magnitude, rapidly taking the contaminant through a step-wise dechlorination process that ultimately results in the production of non-toxic compounds such as ethene and ethane. Under the influence of HRC, this process may continue.

Within the subsurface anaerobic microbial consortium, there exist microbes that use hydrogen primarily for the production of methane (methanogens), and also present are microbes that use hydrogen primarily for dechlorination (reductive dechlorinators). Results from university studies suggest that there is competition for hydrogen between the reductive dechlorinators and methanogens. High concentrations of hydrogen tend to favor methanogenic activity, whereas reductive dechlorinators are best supported in conditions of low hydrogen concentrations (2-10 nM). With HRC's long-lasting, controlled release feature, more steady hydrogen concentrations are possible optimizing reductive dechlorination over competing methanogenesis.