SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

ORDER NO.R5-2002-0148 • • _ 19 - INFORMATION SHEET MUSCO FAMILY OLIVE COMPANY AND THE STUDLEY COMPANY WASTEWATER TREATMENT AND LAND DISPOSAL FACILITY SAN JOAQUIN COUNTY Based on long-standing practice, the agronomic nitrogen loading rate for a given crop is based on the rates presented in the most recent edition of the Western Fertilizer Handbook unless the Discharger demonstrates that another rate is technically justified. Staff has taken a conservative approach in requiring the Discharger to apply nitrogen at agronomic rates. This limit will apply until the Discharger can provide additional site-specific testing data to support their denitrification assumptions. Effluent Limitation C.3 Loading limits for BOD are needed because excessive loading can deplete soil oxygen and cause anaerobic conditions. Anaerobic degradation of organic matter can cause severe nuisance odors and promote incomplete biodegradation, thereby allowing dissolved organic material to percolate through the unsaturated zone into groundwater. Anaerobic decomposition of organic wastes also creates organic acids that decrease soil pH. A low pH environment can cause excessive leaching of metals in the soil into underlying groundwater. This Discharge Specification prescribes a maximum BOD loading of 300 lbs/acre on any one day, and 100 lbs/acre/day as a 7-day(weekly) average. The weekly average loading limit of 100 lbs/acre/day is based on U.S. Environmental Protection Agency Publication (USEPA) guidelines provided in Pollution Abatement in the Fruit and Vegetable Industry— Wastewater Treatment (USEPA 625/3-77-0007) (hereafter Pollution Abatement). Although the RWD states that the yearly average BOD loading will be less than 701b/ac/day, a review of the most recent self-monitoring report(May 2002) shows that the Discharger may not be able to meet the daily or weekly limitations. The Discharger has already proposed to install aerators in its ponds; this step may be all that is necessary to meet the BOD effluent limitation. If not then the Discharger will need to take other steps to improve its treatment system. It is not appropriate to relax the BOD loading rate as staff are still receiving odor complaints. Land Application Area Specification D.19 Land Application Area Specification D.15 requires that effect wastewater application on the soil shall not exceed the buffering capacity of the soil profile. The Discharger has described the disassociation of the bicarbonate ion under certain soil pH conditions but has failed to describe the pH at which the disassociation is anticipated to occur. Pollution Abatement recommends a wastewater pH range of 6.4 to 8.4 for irrigation and Effluent Limitation CA requires wastewater discharged to the land application areas to not have a pH of less than 6.5 or greater than 8.5. This limitation alone cannot ensure that soil pH conditions will be optimal for land treatment and preventing leaching of metals, so Land Application Area Specification D.19 requires that the discharge not exceed the soil pH buffering capacity. Land Application Area Specification D.20 This specification is needed because wastewater application near the property boundary has resulted in nuisance odors for residents. The Discharger's Odor Minimization Report described elimination of standing water in the irrigation checks. Because the soil permeability is so low, staff believe any application of wastewater at the irrigation checks will result in standing water. To prevent anaerobic conditions and associated odor problems in the treatment and storage ponds, this Order also requires the