SITE INFORMATION AND CORRESPONDENCE 1980-1999

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correlation exists between pH metal solubility and concentrations of metals that create thresholds of inhibitory effects in activated sludge treatment processes. We propose utilizing influent pH values as a tripping mechanism for the Discharger to conduct additional sampling for zinc,lead and cyanide. The Discharger should be required to have the daily composite sample analyzed for these pollutants anytime the influent pH meter shows that the treatment plant has received wastewater containing a pH value less than 6 or greater than 10 for any accumulative one hour period. Similarly, many organic pollutants interfere with POTW processes, such as alcohols, phenols, cyanide, chlorinated hydrocarbons, pesticides, organic nitrogen compounds, surfactants, oil and grease, and miscellaneous organic chemicals. Chlorinated compounds such as chloroform, carbon tetachloride and 1,1,1 trichloroethane are toxic to the anaerobic digestion process at very low concentrations (0.5 to 1 mg/1). Sulfide compounds (especially hydrogen sulfide, H2S) are known to inhibit the anaerobic digestion process under certain conditions. These inhibitory effects can increase the likelihood of pollutants being bypassed cough the treatment system. Any exceedance of reported levels of these constituents known to inhibit activated sludge, anaerobic digestion and nitrification processes should trigger requirements for additional sampling. B. Influent Monitoring Of Industrial Wastewater To Ponds. There is no requirement to monitor for pH. A continuous reading meter should be required. This will help to determine if the wastewater is septic and odor causing,help detect illicit discharges of acidic waste and prevent the application of hazardous wastes to land. A continuous reading conductivity meter should also be required. Priority pollutants should be required as part of influent monitoring of industrial wastewater to the ponds because the Discharger has identified several metal finishing processes that discharge into this line. The regulated pollutants including total toxics organics can be found in 40 CFR 433. Priority pollutants should be sampled twice annually as a composite sample because the primary discharger has been noted as a cannery operation that can have seasonal variation in its discharge. For example: peaches and apricots are processed in the early summer months while tomatoes are generally processed in the late summer months. Peaches may receive pesticide spraying prior to harvest whereas tomatoes are generally defoliated prior to harvest. The Tentative Permit states that the"[d]ischarge of waste classified as `hazardous' under Section 2521,Chapter 12 of Title 23 or `designated', as defined in Section 13173 of California Water Code is prohibited." However,the industrial waste from the industrial line is used for irrigation. How can the Regional Board determine compliance with this restriction unless it requires the Discharger to, as least annually,test for hazardous waste constituents. Additionally, DeltaKeeper,Tentative NPDES Permit,Lodi, 17 December 1999,Page 9.