ARCHIVED REPORTS_RPT OF WASTE DISCHARGE FOR WASTEWATER DISPERSAL 2011

Home Browse Search

REPORT OF WASTE DISCHARGE- APPENDIX D Diamond Pet Food Processors of Ripon,LLC June 30,2011 Report of Waste Discharge—Antidegradation Analysis Page 7 of 14 The highest TDS level in the intermediate aquifer was across the central part of the site and in the northeast quadrant of the site in PW-5 (1,100 µmhos/cm). The area of lowest conductivity was in the northwest quadrant of the site in well M-11-C (130 mg/L; Figure 15). Infiltration of plant process water is responsible for the elevated TDS levels measured in the semiperched, upper, and intermediate aquifer over most of the site. The elevated TDS levels in the semiperched aquifer in the northeastern quadrant of the site, however,which have been up to three times higher than effluent TDS levels, are likely caused by the eucalyptus trees' concentrating effect on TDS.6 The elevated TDS levels observed along the western portion of the site,particularly in the southwest corner of the site,probably reflect the infiltration of higher TDS water originating at the City of Ripon's MWWTF encroaching onto the DP site. Stiff patterns are graphic representations of water quality and are created by plotting the concentrations of anions and cations (in meq/L) in a sample on a horizontal axis and then connecting the dots to create a unique pattern for each well. Stiff patterns for all wells are presented in Figure 16. The patterns illustrate that the best groundwater quality is in the southeast part of the site and the most degraded groundwater quality is in the northeastern part of the site. As with analysis of groundwater quality contour maps, the poorest water quality in the northeast can be attributed to the concentration of constituents from evapotranspiration by the eucalyptus trees in this area.7 For the second-half 2010 monitoring report, Mann-Kendall trend analysis was perform for all analytes in all wells. Figure 17 shows a summary of the trend analyses. Trend analyses for TDS show more improvements in water quality in the southeastern part of the site, reflecting application of the higher quality surface or groundwater to the east percolation field. The trend analyses also show more degradation of groundwater quality in the northeastern part of the site, reflecting concentration of constituents from evapotranspiration by the eucalyptus trees,$ and in the southwestern part of the site from the inflow of high TDS water from the City of Ripon's MWWTF. In order to meet the WQPS adopted by the CVRWQCB for the site (Table 3), Diamond predecessor Neenah Paper chose to import low TDS water from the South San Joaquin Irrigation District (SSJID) as the preferred corrective action method for reducing TDS levels in Plant effluent water 6 G.S.Jorgensen,Kenneth H. Solomon,and V. Cervinka,March 1993,Agroforestry Systems for On-Farm Drain Water Management. 7 lbid.P. 8 8 L&A,November 17,2008,Five-Year Water Quality Review Report. 010070.00, Task I Lawrence&Associates w:I clients)diamond pet foods1010107.00-ripon rowdldiamondpet_rowdjune2011_draft.docx