COMPLIANCE INFO_NL STUDY - Laserfiche WebLink

Home Browse Search

„ Organic matter content tested 0.7% at five ft and 0.8% at 25 ft. Although these percentages fare low, the OM that is present can "fix” or bind NH4 ions. L The CEC measures the potential for adsorption of NH4 ions onto clay particles, thus preventing Lnitrification, although not all types of clays have this capability. The analyzed CEC can be considered average for both the 5 ft and 25 ft depths. The H is slightly alkaline. When the Ph is neutral or acidic most of the nitrogen is in the P . g Y � g NH4 ion form. As the pH becomes alkaline, the NH4 is transformed into ammonia and is capable of escape from the soil enviromnent as a gas. Denitrification occurs under anaerobic conditions and requires OM for the denitrifying bacteria. Conditions for denitrification can be enhanced by periodically "dosing" or flooding absorption areas with effluent high in NH4 ions. The ability of the CEC complex in the top 1 m of soil may bind these ions, in addition to creating anaerobic conditions in the high clay content soil. From the above data, we find somewhat favorable conditions for the attenuation of NO3-N formation; a conservative estimate being a 30% reduction. The clogging mat formation in the leachfields should theoretically remove 20% of NO3-N. Although it is impossible to predict an exact concentration of NO3-N loading, a safe assumption is 50% of the total N loading will be in the form of nitrates. Therefore, total NO3-N loading from the project can be assumed to be 546 kg of NO3-N/yr. L It is also impossible to determine the depth of the "mixing layer" where septic effluent mixes with groundwater. Prediction of potential nitrate impact to adjacent wells cannot be calculated without accurate aquifer formation data. Only periodic monitoring of downgradient wells can assess nitrate impact. This of course, is "after the fact." The domestic well at 3730 Wilson Way has been referenced by the Department of Water Resources - "Water Well Drillers Report" as No. 244633. The Local Permit Number is 82-571. Since the screened area of the well is not stated on the DWR report, it is assumed to extend from a depth of 100 ft below grade, to the stated bottom of the well at 200 ft. The following calculations assess potential nitrate impact which may be determined from this well: 11 vaffey Ag Pssearch