Laserfiche WebLink
occurs. Since an integrated approach is being considered to reduce rinse water usage and to <br />eliminate cyanide baths and rinse waters, the double -counting is not considered an issue for <br />(� SLAC. SLAC is trying to achieve source reduction in filter cake by reducing its non- <br />hazardous rinse water usage. <br />Hazardous Waste Management Approaches <br />Two noteworthy practices have been implemented by MFO that have helped reduce filter <br />cake and chemical usage in the,IVIFPF: <br />1. One major source reduction measure that has been implemented since 2006 was the <br />electrochemical generation of ferric hydroxide, which is used as a coagulant/flocculating <br />agent used in the sedimentation of metal precipitates. The electrochemical system . <br />provides better control of ferric hydroxide in the treatment process. An improved ferric <br />chloride meters syptem acts as a backup for the electrochemical system. The <br />electrochemical process provides tighter control of the iron hydroxide than ferric chloride <br />injection. This in turn reduces the volume and weight of the sludge that is generated <br />during the removal of metals in the sedimentation process. <br />2. A second source reduction measure was eliminating the use of hexavalent chromium in <br />cleaning and plating operations in the 20064o-2007 time period and using alternative <br />technologies that provide the benefits of hexavalent chromium without any of the <br />drawbacks. The elimination of hexavalent chromium provided several side -benefits that <br />are not easy to quantify, but definitely contributed to the following achievements <br />a. Eliminated the need to treat hexavalent chromium rinse waters in the MFPF, thus <br />helping to eliminate the tank that was used to convert hexavalent chromium to <br />trivalent chromium. <br />b. Reduced the generation of heavy metal sludge and treatment chemical usage <br />associated with the treatment of hexavalent chromium in the WPF. <br />c. Eliminated the potential for worker exposure from hexavalent chromium in the <br />metal finishing and MFPF work areas. <br />The opportunities to further reduce filter cake are limited. Changing the composition of the <br />sludge to make it lighter may result in more metals passing through to the POTW. The purity <br />of rinse water used by WO is high in order to retain a high degree of quality that is needed <br />for parts that can be in service in ultra-high vacuum environments used by SLAC to operate <br />the two-mile accelerator, as well as to conduct various experiments demanding high purity <br />materials under ultra-high vacuum conditions. <br />Rinse water is necessary to meet the stringent cleaning and plating specifi <br />cations required at <br />SLAC. MFO strives to reduce quantities of rinse water usage in its operations where <br />feasible. The MFPF is a conventional pH adjustment -flocculation -sedimentation <br />pretreatment system that is economical for SLAC metal finishing operations. Alternative <br />treatment technologies to reduce water usage can reduce usage of treatment chemicals, but <br />are not always reliable, due to the variable conditions that can occur in these operations for <br />the metal finishing work performed. <br />September 1, 2015 SB14 Plan ffi-14 <br />