### 316B RULE **TELEPHONE LOG** Name of Caller: John Sunda, SAI C Date: August 25, 2009 Company Name: ProChemTech International Inc. Street Address: City /State/ZIP: Pennsylvania Person Contacted: Timothy Keister Title: Certified Water Technologist Tele phone # 814

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- 0959 Called to inquire about technical, treatment chemical usage and cost issues regarding the impact of increasing cy cles of concentration (COC) in co oling towers. Contacted Mr Keister after reading his paper “Cooling Water Management B asic Principles and Technology.” He said they

don’t have many

power plants as clients but have worked with plants up to 2000 MW. A recent client is a 90 MW plant Scrubgrass Generating plant in Pennsylvania. He said that most power plant use very rudiment ary

treatment chemical s ystems for their cooling towers such as using biocides onl y . For example they may onl y use chlorination and some still use chlorine gas. Ingeneral as you increase the cycles of concentration the biocides costs will not vary that much but y ou will need to start using an antiscale treatment chemical like phosphonate and a solids dispersant like poly acrylate. If they are already

treating makeup water for corrosion, scale, or solids increasing COC may actually reduce treatment chemic al costs. They

have found that the optimal COC with respect to chemical costs is in the range of 3 to 6. Also y ou may want to treat with acid to reduce pH. Although his paper does not recommend using acid this is mostly advice for smaller HVAC and industrial sy stems. For a t ypical system operating around 3 to 6 cy cles of concentration, the following dosage would be appropriate: Phosphonate at 2

- 4 ppm Poly acr yl ate at 4

- 5 ppmThe above treatment regimen including acid treatment is what they used at Scrub grass. For high hardness water such as in Arizona the COC limit for such a sy stem might be 3 but in the east it would be around 6

- 7. He said USGS has a hardness map to get an idea of distribution nationwide (found at http://water.usgs.gov/owq/hardness

alkalinity .html#hardness ). These chemicals are non

- toxic and do not contain any of the priorit y pollutants regulated in the steam generation effluent guidelines so they should pose no problem with respect to direct discharge of cooling tower blowdown. There may

be a small amount of COD. I asked about water qualit y and phosphorus discharge

– he said this could be a problem. For example he was advising the PA DEP change their plans to use poly phoshates in their office towers because it might not appear appropriate for the PA DEP to be discharging Phosphorus into the Susquehanna when they are requiring others to limit discharge of P Each chemical would require a chemical feed pump whic h would be relatively small in cost around several $1000 per pump. They would also require costs of some labor for maintenance and the chemist to run tests. Most power plants have an onsite chemist. As described in his paper, they would also need to ins tall a sy stem to control the cy cles of concentration. The simplest and most reliable is to install a meter on the makeup water which in turn controls the blowdown pump such that blowdown is some fraction of makeup. The largest cost would be for the meter which for the largest one he sells

– 8 in for up to 1430 gpm would cost $4,000. He said they generally use a rule of thumb that installation will equal equipment costs He said a full s ys tem including chemical feed and COC control for a large 2000MW power p lant might cost $20,000 to $25,000

. I also brought up side stream filtration. With regard to solids particles in the <2 micron range are easily

controlled with dispersants like poly acrylate. Those in the >25 micron range can be controlled with settling an d cy clones etc. It is the solids in the 2

- 25 micron range that are the most problematic and that multimedia filters are useful if that is a problem. Most power plants don’t use filters but some may in the future. He said a 1,000 gpm multimedia filter s yste m would cost about $250,000. I asked about disposal of solids backwash and he said that at coal plants could easily be discharged to the ash pond. Other benefits besides 316a & 3126b: Chemical costs may

be reduced if they

are operating below the optimum C OC. The addition of better chemical treatment can reduce corrosion of equipment especiall y for the condensers b y a factor of 5

- 6X. He said some power plant operators disregard corrosion because they

argue the plant equipment is only expected to last 15 y ears.Another benefit is that by substantially reducing the blowdown ( applies both to once through and closed cy cle ), the discharge of biocide is reduced since the volume is smaller and it is easier to treat (e.g., dechlorinate) smaller volumes. Same for oth er treatment chemicals since blowdown volume is reduced.