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[6] CONCLUSIONS The percolation rates and the depths at which they were performed illustrate that seepage pits will have to be used for any future septic systems on the subject parcel and Designated Remainder. Additionally, the information obtained from the Environmental Health Department concerning the number of Application permits for seepage pits also indicates a need for this type of septic system for the area. The number of seepage pits for a proposed residence or other type of structure will be dependent upon the number of bedrooms the structure will have, or the number of occupants, particularly children. The pits should be at least 33 inches in diameter and installed to a maximum depth of 25 feet. All related development structures such as wells, leachfields, etc. will have to comply with the published "distance" requirements from applicable objects. Each proposed septic system should have a 12,000 square foot leachfield area due to the virtually non-existent perc rates that would occur at the 42 inch depth. A 50% standby replacement area must also be incorporated into any design. This proposed leachfield area will help ensure stability and guard against leachfield failure. A failure would primarily result from the formation of a "biomat" or "clogging mat" on the wetted soil where the eluent enters. This mat is composed mostly of aerobic and anaerobic bacteria and bacterial products consisting of a slime of polyuronides and polysaccharides. If the soil/effluent interface is well aerated, a variety of soil microfauna such as nematodes and protozoa may digest the clogging mat bacteria. However, due to the high clay content of the shallow soil horizons, anaerobic conditions will most likely prevail. With respect to the protection of the underlying groundwater from pathogens and nitrates (NO,), the soil structure of the subject parcels, along with the depth to groundwater, can be considered favorable ` for prevention from contamination. It is our opinion that the existing septic system and any future SFR septic system will have an inconsequential impact on the groundwater. a. The nitrogen cycle and the eventual formation of nitrates are highly complex within the soil environment. The subject parcel soils are conducive for two beneficial nitrogen cycle processes, namely fixation of ammonium and denitrification. Fixation of ammonium(NH4) can occur with the adsorption of ammonium molecules onto expanding clay particles, which is the predominate shallow L soil texture of the subject site. With this adsorption, ammonium becomes "fixed" and is unavailable for biological transformation to nitrate. Q-lity Uo"t.1 I-Plaiou