CC PACKET 09251984 - Laserfiche WebLink

Home Browse Search

14. He indicated that the cadmium and chromium limits might be lower because of Superfund, and this is shown in the table too. Regarding the question of whether the CRF can meet these metal limits-1 have attached a graph and table from an EPA publication (Lancy, R.E. and Rice, R.L., Waste Treatment Upgrading Metal-Finishing Facilities to Reduce Pollution, Environmental Protection Agency • Technology Transfer, July 1973, revised January 1974, EPA 625/3-13-002), but originally published in Germany. The graph seems to represent the EPA's official position and has been reproduced in many publications. It shows the lowest solubilities that can be achieved for segre- gated cadmium, chromium, copper, nickel, and zinc salts in distilled water con- taining a. strong base. The table shows the effect of hard water. Note that even in hard water it is possible to meet the MWCC limits for segregated metal streams. The solutions -from the regenerated canisters are segregated and these represent about sixty percent of the flow. Most of the batch dumps also repre- sent segregated metal solutions although somewhat contaminated. There are, however, rinses and some batch dumps such as those from zinc chromating which may present a problem because they contain two or more metals and the the opti- mum pH for precipitation differs markedly for the different metals. In these cases two hydroxide precipitation steps or polishing with sulfide or ion exchange canisters will be used to meet the limits. There may also be dif- ficulties with certain streams containing chelating agents, such as electroless copper and electroless nickel . The chelating agents will be removed using acti- vated carbon if this is necessary to meet the limits. Lead has not been men- tioned here as the CRF may be handling lead only as already precipitated sludges containing copper, lead, and tin. Regarding the cyanide limit, it has been our intention to oxidize cyanide with chlorine, chlorine dioxide, or sodium hypochlorite. One should be able to assure complete destruction of cyanide by using a long enough detention time in the reactor and using a dose high enough to assure a small chlorine residual . The exact conditions required, however, will not be known until tests are done early in the design process. In various documents EPA seems confident that the limits can be met. It has been our intention to neutralize each batch of CRF wastewater to pH 7 before discharge. This will certainly meet the MWCC limits of pH between 5.0 and 10.0 at discharge. Neutralization of CRF wastewater will raise its dissolved solids content because the reaction product of sulfuric acid and caustic is sodium sulfate. I have already estimated the sodium sulfate discharge in my 1983 February 10 memorandum to Dan Shuster, which is attached. At 0.25 percent sodium sulfate the Central Facility's 75,000 gallons per day would contain about 1,560 pounds per day of