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Calculation of Alkalinity Requirement for Nitrification Nitrate loading is contingent upon several environmental factors required for nitrification to occur within the soil environment, or as in the case of the Carmelo Industrial Park, within the EnviroServer 1200. Soil conditions include soil pore-space oxygen content, soil temperature, pH, electrical conductivity, organic matter, cation exchange capacity, and alkalinity. Alkalinity in wastewater effluent is derived from the domestic water supply in addition to the introduction of wastes. Nitrification consumes approximately 7.1 mg of alkalinity for every mg of ammonia-nitrogen (NH4-N) oxidized. For inexplicable reasons, ammonia nitrogen was found to be Below Detectable Limits (BDL) within the conventional septic tank. The organic nitrogen was determined to be in very low concentrations at 1.9 mg/L. However, the ammonia nitrogen concentration within the EnviroServer was 12.7 mg/L, with the nitrate concentration at 177 mg/L. Therefore, the alkalinity concentration in both the domestic water supply and the wastewater would have to be substantial for such high nitrification to occur. It is theorized that alkalinity is being consumed, but at a slower rate due to relatively low alkalinity concentrations to allow for such high levels of nitrification. This is evident by the decrease in alkalinity of 48 mg/L between the conventional septic tank and the EnviroServer. (245 mg/L vs. 197 mg/L) V. CONCLUSIONS AND RECOMMENDATIONS Analysis of the raw sewage influent that enters the conventional septic tank reveals very low and non-existent concentrations of the various nitrogen fractions. This may be attributable to any number of factors including dilution from fresh water, continual pumping of the influent to the EnviroServer, or laboratory error. Effluent analysis of the EnviroServer effluent reveals an extremely high nitrate concentration of 177 mg/L, which is 39x over the Maximum Contaminant Level (MCL) of 45 ppm. Explanations for this high nitrate concentration must be due to the inadequacy of the EnviroServer 1200 to denitrify the effluent after it has been nitrified. Laboratory error has been ruled-out: When the test results were received, it was decided to immediately have the laboratory re-run nitrate analysis on the sample. The initial analysis was confirmed with the same test results. Without intricate knowledge of the EnviroServer, it can only be assumed that during the sequential batching of the denitrification process within the EnviroServer, there may be insufficient organic matter content. Consequently, influent wastewater from the new development will not flow into a septic tank, but rather a pump chamber with a grinder pump so that solid particulate matter will be pumped to the EnviroServer for processing. This additional organic matter may be beneficial for the denitrification process. Nitrate impact to the underlying soil was quantified after receiving the EnviroServer effluent test results. As referenced, sampling soil for nitrate-nitrogen content is second-best to sampling actual vadose zone water, which was not practical or possible due to the tight, clay soils. Page -6- Chesney Consulting