July-August 2007

Bulls Eye!

Targeting California’s high-volume urban water users

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By Lyn Corum

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SFPUC sent out introductory letters to the targeted high-volume customers introducing the program. It is offering to help them cut overall water usage and water costs up to 20% by implementing projects with paybacks of two years or less. Intergy is now busy marketing the program to those customers and offering free engineering and technical support, plus additional financial incentives from Pacific Gas & Electric (PG &E) if they want to reduce energy usage for hot water processes.

Haasz says customers are happy with the program. “Anything they save in water reduces wastewater and sewage bills.” There is also a conjunction with energy savings, she says.

Cutting Cooling Tower Water by Two-Thirds
Richard Fox, director of engineering at Intergy, says most of the company’s projects are still in the planning phase or are waiting for customers’ decisions. He described two projects that were completed around the time Intergy signed the contract with SFPUC and that he would like to see duplicated with other customers.

The San Francisco Chronicle installed a chemical-free cooling water treatment unit to treat the water running between its dual 250-ton cooling towers and chiller system. Joe Simpson, the newspaper’s chief engineer, discovered the Dolphin system, manufactured by Clearwater Systems LLC, at a trade fair two years ago. After reviewing test sites at state facilities where it was installed he decided to go ahead with the installation at the newspaper. The system reduces water use by about two-thirds, he says, because water can be circulated 15 times before the increasingly contaminated water needs to be discharged rather than the typical five times with chemical treatment.

Dan Daniel, with Advanced Cooling Tower Technologies Inc. in Concord, CA, the northern California distributor for the Dolphin system, describes it as an inline treatment system that uses electric pulses to control scaling, biological growth, and corrosion. It is a PVC module that is fitted into the circulation water line running from the chiller to the cooling tower. A small control panel installed nearby generates 30-kilohertz pulses, which run through coils on either side of the PVC module. The system installed on the Chronicle’s circulation water line pulses 60 times per second. The new Dolphin 3000 system pulses 240 times per second for increased bacterial control, Daniel says.

Daniel explains that the electrical pulses strip the charge off mineral molecules, changing the way the minerals precipitate in the water. A non-adherent mineral powder ball is produced, thereby preventing hard-line scale from forming. Bacteria are encapsulated in the mineral powder ball and cannot reproduce resulting in low bacteria populations. Dissolved calcium also sticks to the mineral powder ball. The powder ball is readily filterable and is easily flushed out with the cooling tower’s automatic bleed. Daniel also says when calcium comes out of solution it forms a natural cathodic corrosion inhibitor.

Daniel says yearly savings with the Dolphin system at the Chronicle are estimated at $14,480. This includes savings of $1,485 on water, $1,485 on sewer disposal, $1,200 on maintenance, and $4,000 with the elimination of chemicals. Furthermore, there is $7,560 in energy savings, based on a 5% improvement in chiller and cooling tower efficiency due to the elimination of the slime layer. The increased electrical costs of $1,250 are subtracted out.

The total cost of the Dolphin system installed was $17,100, producing a payback period of 1.2 years. Simpson says he wouldn’t know what the actual savings are for a year, given that it went online in November 2006.

Cutting Sterilizer Hot-Water Use
St. Mary’s Hospital in San Francisco hired American Energy Assets (AEA) to install thermostatic control valves on each of its eight sterilizer units to control water input and output of “tempering condensate,” according to Jack Pecoraro, project engineer with AEA. Hot water has to be drained from sterilizer jackets, which are steam-heated, and cooled before it runs into steam traps 24 hours a day to pass regulations. The thermostatic control valve allows water to be drained only when it needs to be drained. Completed at a cost of $1,500 per unit on the eight sterilizers in August 2006, water savings were estimated to be 628,336 gallons per year, says Pecoraro.

AEA also replaced 1,200 toilets at St Mary’s with new low-flow toilets, which flush water at 1.6 gallons per flush and installed aerators on faucets.

Intergy’s Fox is eyeing laundry water treatment and recycling systems that could save up to 80% of laundry water usage. Fox says a linen service in San Francisco is considering this technology that would save 30 acre-feet per year or 10 million gallons of water annually. Smaller laundries could save 10 acre-feet per year, says Fox.

Metropolitan Water District
Fox might take a cue from Republic Master Chefs in Los Angeles. Republic received incentives from the Metropolitan Water District (MWD) after the Los Angeles Department of Water and Power referred the company to the regional water district. Starting in March 2005, Republic and its parent company, American Textile Maintenance, installed $390,000 of new equipment to reclaim wastewater leaving tunnel washers. The project was completed in September 2005.

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Wastewater is collected and pumped to a shaker to separate out solids. Next, suspended solids are removed before the water passes through ceramic filters for purification. The water is then pumped into a holding tank, without any heat loss, before being returned to the tunnel washers for reuse.

This new system was estimated to save the company 16.5 million gallons of water per year or as much as 38% of the laundry’s annual water usage. After one year’s monitoring by the MWD the new system saved 20 million gallons. Republic qualified for almost $40,000 in incentives. The MWD paid 50% of the incentive, $19,500, to help the company with upfront installation costs. The balance of the incentive was paid following completion of the monitoring to verify the savings. Next Page >

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