SU0002258_SSNL - Laserfiche WebLink

Home Browse Search

r In addition to estimating wastewater loading rates, climatic stress must also be considered regarding the loading of the septic system. Leachfields must transmit two hydraulic loads: the effluent load and the climatic load during the rainy season. The average yearly rainfall in the Stockton area is 13.50 inches which is significant enough to influence hydraulic loading. When soils with hydraulically limiting horizons (such as clays or a high groundwater table) are used for disposal, hydraulic stress occurs when the total effluent load plus precipitation exceeds the transmission rate through the clay horizons. During the rainy season, both climatic and effluent loads may have to be stored above these limiting horizons. If the project leachfield contains inadequate storage capacity, which is a possibility, the seepage pits will then manage the effluent flow. To reduce wastewater flows originating from the Kingdom Hall, "ultra low-flow" sinks and 1.5 gallon flush toilets should be installed in the restrooms and apartment area. Sinks should have spring-loaded fixtures to prevent accidental overuse and the apartment should have a low-flow shower head. It is assumed there are no future expansion plans of the new Kingdom Hall, If the possibility exists for expansion of the apartment area, or the addition of kitchen facilities, the entire operation and design of the septic system must be reviewed and may have to be revised. I VI. NITRATE LOADING To calculate the nitrate loading for the proposed project, it is important that accurate wastewater flow volumes be projected as best they can. The initial flow volume for the Kingdom Hall has been established at an Average Daily Flow of 1400 gallons. This flow volume is similar to a housing L subdivision or industrial/commercial facility whereby the maximum flow can be determined and there is usually not much deviation from this initial flow volume. 1.2 As sewage enters septic tanks, approximately 25% to 33% is part of protein, with the remaining portion as urea. In the septic tank and the soil environment, ammonia from urea/protein decomposition, combine with water to form the ammonium ion - the precursor to nitrate. Aerobic bacteria oxidize ammonium to nitrate usually within two to five feet of unsaturated (aerobic) soil. This is called nitrification. Virtually complete nitrification of ammonium nitrogen occurs in the -� unsaturated zone in well-aerated soils under leachfields. However, as referenced, the indigenous soils are not well aerated due to their high clay content. This factor may attenuate nitrate formation and promote denitrification. Denitrification is the only mechanism in the soil which can significantly reduce nitrate concentrations in percolating effluent. It is the biological and chemical lj 6 Vaf zy Ag P�fsearch