SU0003465 SSNL - Laserfiche WebLink

Home Browse Search

C 4.) Septic System Contributions: Data from various sources including independent investigators, the U.S. EPA, and the Regional Water Quality Control Board estimate nitrogen I from domestic sewage to be 12 grams N per person per day (g N/capita/day) to a high of 90 g N/capita/day. Hantzche and Finnemore (1992) correlated septic tank effluent concentrations multiplied by water discharge to the septic tank. They formulated a water discharge of 100 gal/capita/day with an effluent concentration of 30-60 mg NIL. It is our opinion that 60 mg NIL is most accurate for this type of operation. The following calculations determine nitrate-nitrogen loading from septic system contributions: 12 people max. on-site x 100 gals/day= 1200 gals x 3.79 L/gal =4548 L/d x 60 mg NIL = 273 grms N/day x 365 days/yr= 100 kg N/yr x 2.2 lb/kg =220 lbs N/yr. This impact is negligible in comparison to the amount of nitrogen produced by the dairy facility and used by the associated cropland. C. DAIRY NITROGEN PRODUCTION CALCULATIONS As referenced, the Rocha Dairy sells all of the manure solids produced by the dairy population for off-site use. The Nutrient and Irrigation Water Management Plan(NIWMP) calculations found in Appendix"F" demonstrate the facility may apply liquid manure (nutrient water) on all the above- referenced cropland acreage without overload. The NIWMP document was formulated by the Central Valley Regional Water Quality Control Board in Sacramento. In addition to the current Rocha Dairy cow population, a second NIWMP was prepared to illustrate a reasonable maximum dairy cow population, again, based on ther��emse that all solids are exported. A reasonable maximum number of milk cows was formulated without attempting to exactly equate liquid nitrogen produced by the dairy herd with crop nitrogen requirements, because total nitrogen excreted from dairy animals is difficult to quantify. The rates of several important nitrogen transformation processes can only be estimated. Therefore, a safety factor was incorporated. Secondly, the fact that the animals will be confined under two different housing structures (flushed corral vs. freestall) during different times of the year creates differences in nitrogen loading. The calculations incorporate the use of animal units (AU) for the Holstein dairy cow to formulate nitrogen loading. In addition to the current lease arrangement between Mr. Rocha and Mr. Moreda, Mr. Moreda also has his own dairy and heifer ranch in Petaluma, California. For six months out of each year, he raises all his heifers on pasture land and then transports them to the Rocha Dairy facility. Consequently, the heifer animal units listed in the N1WMP could be adjusted downward; however, they were not. I' The following Table illustrates the current milk cow population in comparison with the theoretical maximum number of milk cow the facility can support: 11 Chesney ConsuCting