gen013,
Our expertise is in sodium lactate and chitin for soluble and slow release hydrogen donors. For sodium lactate, we target initial in situ concentrations in the treatment volume (treatment area times saturated thickness times effective porosity) of 1000 mg/L. If you assume a factor of 8 to 20 dilution factor when injecting into the saturated zone, you would need to inject 8,000 to 20,000 mg/L lactate. Because a much smaller proportion of molasses is converted to hydrogen donors like propionate than when sodium lactate is fermented, you will likely need to inject more at higher concentrations to achieve complete dechlorination of the PCE.