ARCHIVED REPORTS_JULY 2014 FINAL RCSI

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2-13 Forward Composting Facility SWT Engineering Report of Composting Site Information - July 2014 z:\projects\allied waste\forward\resource recovery facility\5 yr permit rvw 2013-14\rcsi 2014\text\sec 2.doc ♦ A 30-foot layer of material consisting of very stiff to hard silt and lean clay. This material is moist to wet, with moisture contents between the plastic and liquid limit. This material has an approximate OCR of 1.7 (CH2M HILL Boring BH-1, approximate depth of 78 feet). ♦ Very dense poorly graded sand was observed near the bottom of the CH2M HILL Boring BH-1, starting at an approximate depth of 100 feet. Sand was also observed in EMCON's Boring No. 17 to 178 feet, the maximum depth drilled (EMCON, 1972). Soil type and properties of the materials encountered in the geotechnical investigations performed by EMCON and InsituTech were generally consistent with the conditions determined by CH2M HILL described above. In EMCON's subsurface investigation, a Modified California Sampler (with a 140-pound hammer with a 30-inch drop) was used to collect samples. Blow counts recorded with the Modified California Sampler typically ranged from 20 to 60 blows per foot. Unconfined compression tests were performed on silty clay samples between depths of 3 and 10 feet. The compressive strengths ranged from 1,310 psf to 5,100 psf for an average of approximately 3,000 psf (Note: the undrained shear strength is defined as one half of the unconfined compressive strength) (EMCON, 1972). Shear strengths based on InsituTech's CPT data (performed to a maximum depth of 50 feet) typically ranged from approximately 4,000 psf to over 10,000 psf. Based on these CPT logs, a lower bound shear strength value of 2,000 psf was used in InsituTech's stability evaluation for WMU E (InsituTech, 1987). Table 2 summarizes the results of the subsurface soil investigations for the six generalized zones mentioned above. 2.2 Monitoring Sampling. Forward will analyze at least one composite sample for every 5,000 cubic yards of compost to be analyzed at a Department of Health Services approved laboratory . Compost product, which exceeds the maximum metal concentrations or maximum acceptable pathogen concentrations, shall be designated by the appropriate State or Federal jurisdiction for another use, including disposal, additional processing, ADCs or other uses. A composite sample will consist of 12 mixed samples as collected by the Operations Manager. The Operations Manager uses a shovel to extract each sample. The 12 samples will be of equal volume. Four samples will be extracted from around and on top of the compost pile at different cross-sections as follows: ♦ One-half the horizontal width of the pile ♦ One-fourth the horizontal width of the pile ♦ One-eighth the horizontal width of the pile Results from sampling of the finished product should be sent directly to the LEA from the certified laboratory. Metal Concentrations. The maximum acceptable metal concentrations are presented in Table 3. Tests for metal concentration will be conducted at a certified lab: Pathogen Reduction. In accordance with 14 CCR, Section 17868.3 (Pathogen Reduction), the density of fecal coliform in the stabilized compost, that is or has at one time been active compost, will be less than 1,000 most probable number (MPN) per gram of total solids on a