Brown R.,EE and T Inc. |
Wichser R.,Rivanna Water and Sewer Authority
Water Quality Technology Conference and Exposition 2011 | Year: 2011
• Alum dose reduction, improved DBP precursor removal, etc. were observed • Impact of NaCl vs. NaHCO3 regeneration - No impact in DBP precursor removal, alum dose reduction, etc. during test period • But deterioration in nitrate removal was noted over time - However, there was evidence that NaHCO3 was not displacing some of the materials (e.g., high SUVA organics) removed by the resin • Therefore, if test had gone longer using only NaHCO3 regeneration, might have eventually seen problems with organic removal, alum dose reduction, etc. • DOC in waste was lower than predicted (based on DOC removal from raw water) • SUVA in waste was lower (∼2 L/mg-m in Scottsville waste vs. 5.0 L/mg-m in raw) • Ion exchange activity was not fully recovered in resin regenerated in field with NaHCO3 (but was recovered after regeneration with NaCl in laboratory) - Corrosion implications • Chloride sulfate ratio was 3.4 mg/mg with NaCl vs. 1.1 mg/mg with NaHCO3 - indicating potential increase in susceptibility of water to promote corrosion - Edwards and Triantafyllidou 2007 • Experiences at full-scale facilities - Improved DBP control - Lower treatment chemical doses, including chlorine • Improved chlorine residual maintenance even though dose lower - When NaHCO3 used, 1 week NaCl regeneration for every 3 weeks of NaHCO3 recommended • Recommendations - Use of AIX can improve DBP precursor removal, even though treatment chemical use (including coagulant and chlorine) are lower • Lower coagulant dose has a number of benefits, including residuals handling - NaCl regenerated resin has satisfactory performance, but NaHCO3 can be used instead • NaHCO3 waste may be easier to deal with • Lower chloride to sulfate ratio of treated water produced from NaHCO3 regenerated resin may improve corrosion control characteristics • Repeated regeneration with NaHCO3 may not displace some materials removed from the raw water by the resin, requiring periodic regeneration with NaCl (as noted above). 2011 © American Water Works Association AWWA WQTC Conference Proceedings All Rights Reserved.
Cleveland C.,Carollo Engineers |
Gutierrez R.,Carollo Engineers |
Carlson P.,Carollo Engineers |
Cornwell D.,EE and T Inc
American Water Works Association Annual Conference and Exposition 2012, ACE 2012 | Year: 2012
Project synergy for combining multiple CIP projects Look at the cost of money Timing Sources (grants, SRF loans, muni bonds, private bonds) Optimize most expensive existing and planned treatment processes Maximize production rates Work with regulators Pretreatment loading rates- improve chemical flash mix to reduce chemical use Increased filtration rates Optimize operation and backwash procedures, FTW, RTW, polymer addition, filter run time vs UFRV Minimize O&M costs (chemicals, energy, staffing, automation) Use design tools to maximize efficiency in production of contract docs.
Mctigue N.,EE and T Inc.
Journal - American Water Works Association | Year: 2011
Use of competency models in water treatment industry could prove to be beneficial in attracting, training, and retaining personnel. A competency model complements the position description by providing detailed, behavioral descriptions of key competencies needed to perform a job well. The model may contain specific technical competencies required by the position, but it also includes nontechnical skills, characteristics, and abilities that are required to perform the job well. Knowing the competencies for a job enables employers to select jobholders who already possess some of the competencies and are therefore more likely than other candidates to achieve effective or superior performance and to receive rewards and recognition that cause them to remain in the organization. There are a number of data-gathering methods for identifying the competencies for a particular position. A good competency model should include all of the competencies, both technical and nontechnical, that are needed for effectiveness.