Presented by Scott Leland City of Fairfield Water System - PowerPoint PPT Presentation

Presented by Scott Leland

City of Fairfield Water System  Population >109,000  Service connections > 30,000  Two Treatment Facilities:  North Bay Regional WTP (40 MGD)  Waterman WTP (30 MGD)  Waterman Treatment Plant:  Source water – Lake Berryessa via Putah South Canal (PSC)  Largest Single Customer – Anheuser Busch

Waterman WTP Timeline  1974-76 Original Construction (15 MGD)  1985 Add Two Filters (22.5 MGD)  1991 Add Ozonation (Pre – Ozone)  2006 Operations Building Upgrade  2007-09 Plant Expansion (30 MGD)  Actiflo, Intermediate Ozone, 4 new filters  2015 Add Carbon Dioxide

Waterman 2007 and 2009

PSC Water Quality  Strong Buffering Capacity  Annual Average 2014 2015  pH (units) 8.48 8.49  Alkalinity (mg/L) 171 167  Hardness (mg/L) 179 184  Requires excessive Alum dose (40+ mg/L) to treat daily average turbidity of 3 NTU.

Innovation  Challenge - adjust influent pH  Motivation - reduce costs  Possible Solutions:  Addition of Sulphuric Acid  Addition of Carbon Dioxide  Benefits of Carbon Dioxide  Lower System Cost  Way Less Hazardous than H 2 SO 4  Plentiful Suppliers  Meets Public Health Standards

2011 CO 2 System Components  Tank, Evaporator, Control Panel, In-line Diffuser

CO 2 - Testing, Results, Savings  Carbon Dioxide and Alum  CO 2 dose of 8.1 mg/L reduced pH from 8.5 to 7.4  50% less Alum required for treatment  $74,000 (29%) savings vs traditional operation  CO 2 and PACL ( New Primary Coagulant for WTM )  CO 2 dose of 1.5 mg/L reduced pH from 8.5 to 8.1  PACL dose of 5.8 mg/L required for treatment which = about 1/3 of typical Alum dose for same conditions  $162,000 (63%) savings vs. traditional operation

2015 CO 2 System Components  Tank Evaporator  Control Panel In-line Diffuser

Barriers/Challenges  Plant recently underwent $63 million upgrade – awkward to ask for another $300,000K  Rented metering equipment unreliable  CO 2 injection affected pumping capacity  Tank design issues delayed project completion by 60 days

Benefits of CO 2 Addition  Significant Cost Savings  Bulk CO 2 pricing discount $0.32/lb. vs. $0.0475/lb.  Reduced Alum use/cost  Reduced Caustic use/cost  Less sludge generation  Enhanced Operator Tool Box  Additional primary coagulant choices  Exacting control of influent pH  Optimal TOC removal

Staff Training  Contracted engineering firm designed testing plan and final bulk tank  Initial test system not critical to finished water quality – (room to experiment)  Hands on learning from rented system (3 years)  Minimal operator/staff training  Boost to Operator confidence

Lessons Learned  What worked:  Included staff in design and review  Included product supplier in design process  What didn’t:  Communication between owner (City), project designer, tank manufacturer, and project contractor very inefficient. Delayed project completion by > 60 days.

Questions… Thank you!