03-F Water/Sewer (5/15/03) - Laserfiche WebLink

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City Council Water & Sewer Subcommittee May 15, 2003 Page 4 The purpose is to scrape the sludge and keep it mixed up so it can be sprayed on the field. We are recycling approximately 800,000 gallons of water per day that otherwise would be pumped to the creek and would have to be replaced by pumping additional water from Pat Mayse Lake at additional cost. The recycling of this water saves approximately $66,500.00 per year. We make beneficial use of this sludge by spraying it on a field adjacent to this plant." City Manager Malone said there is a new mandate that we refer to as the backwash recycle rule. The rule was implemented on January 1st and its purpose is to prevent the contamination of our drinking water with recycled backwash water with too high a concentration of Giardia and Cryptosporidium, both of which cause serious health problems to some people. There are rules that limit disposing of sludge by sending it down the creek. We have a permit to apply the sludge to the land adjoining the plant which is an efficient and cost effective means of disposal. We have never had an effective way to keep the sludge in suspension in the basin that we are pumping to the spray field, so that the solids settle into the bottom of the basin. As these solids build up in the basin, the contaminants are concentrated and there is more chance of spillage over into our water treatment process as we draw the recycled water off the top to return to the water treatment process. We are returning the recycled water from the sludge basins to save money. The new mandate is more strict about the quality of the recycled water that we are reusing and the funds budgeted are to be used this summer to address this problem. City Manager Malone advised that Mr. Campbell budgeted $40,000.00 to cover the contingency of purchasing commercial sludge handling equipment designed for this purpose. Again, illustrating the conservative use of city resources, Mr. Campbell began experimenting with a cheaper alternative this past fall. He said that Mr. Campbell previously bought for salvage value some surplus floating mixer/aerators from John Kraft Sesaco Company in Paris, which we have been using in these basins for several years without achieving the desired effect needed to meet this new mandate. Mr. Campbell has designed some modifications to these floating mixer/aerators and has had a prototype fabricated. We have been testing the modified mixer/aerators and believe that