CCMIN030403 - Laserfiche WebLink

Mr. Marchand said Zone 7 is filtering water right now. There are agencies which are under Federal waivers where they do not have to filter the water. Zone 7 filters the water which is an effective barrier removal for cryptosporidium. Zone 7 does not find it in its raw water. At what point do you not find something that does not exist? We test for it, we are looking for it in our raw water. Cryptosporidium is a very bad thing and we do monitor for it and we treat the water to remove it in case it was there. The turbidity, the suspension of particulates in the water, removes all of the suspended particles in the water to a certain turbidity level. The thought is that at that level there are no suspended particles in the size range that would be indicative of the presence of cryptosporidium Ms. Hosterman asked about disinfection byproducts and asked Mr. Marchand to briefly discuss this. How is it monitored? She is concerned about maximum contamination limits which are regulated by the California Environmental Protection Agency and the maximum contamination limit goals that are monitored by the United States Environmental Protection Agency. How often are the inorganic compounds of arsenic, radon, and chromium VI tested for? Mr. Marchand said Zone 7 is required to test quarterly for most of the compounds in question. Some are required once a year, depending on the potential for them showing up. There are some compounds you can test for quarterly for several years, and if not present, you can reduce the monitoring to once a year. Radon, for example, has been monitored for years. Zone 7 has not been mandated to test for it. There is required language in the consumer confidence reports about radon. In 1979 it was realized that chlorination of drinking water caused the formation of disinfection byproducts. There was a lot of talk of going to ozone. This causes a disinfection byproduct called bromides, which might be even worse. For evcx-y solution there is a problem. This is why we switched from free chlorine to chloramines. It does not give a nice bleaching action that the free chlorine does. In the old days you could use a lot of chlorine and bleach out the earth and musty odors. With the advent of chloramines that tool is not available. Some studies show that 90% of the disinfection byproduct precursors come from the San Joaquin drainage. This is why Zone 7 has been very active in trying to get the Cal Fed process moving whereby we can get some means of getting a better water quality. Ms. Hosterman said she heard that Zone 7 does filter where other agencies do not. She asked Mr. Marchand to briefly discuss UV and how it works, what it would take to implement something like it, and how effective it is. Mr. Marchand replied that UV is a real interesting thing because for years people did not think it worked. UV takes money. The water right now meets all of the State and Federal drinking standards. Cryptosporidium has not been found in the source water. It has been found in other source waters throughout the State, but Zone 7 has not had this problem. Zone 7 is looking at going to UV disinfection as well, just to get the extra measure in effect. This is going to be an additional cost incurred. Pleasanton City Council 16 03/04/03 Minutes