|Name:||“NPDES Permit Compliance: Treatment Plant Alternatives" - June 2012|
This staff memo provided the Board of Directors with an evaluation of the National Pollutant Discharge Elimination System (NPDES) compliance for aluminum and dichlorbromomethane (DCBM) including an overview of the problem and current planning, sources of contaminants, and a discussion of treatment alternatives to accomplish the following: 1. reduce DCBM with a lower chlorine dose and add ozone or ultraviolet light to reduce chlorine demand; and 2. use an iron coagulant instead of aluminum to remove total aluminum in the NPDES discharge to Magalia Reservoir.
Please note that regardless of the potential lower cost to implement the alternatives listed above, staff believes the following: 1. the alternatives are shortsighted water supply engineering; 2. require long-term pilot testing; 3. places the District at continued risk for further NPDES compliance violations with increasingly stringent limits (i.e. iron toxicity; fish gills), penalties and more costly requirements; 4. likely result in shortening the life-cycle of the plant due to unforeseen consequences; 5. increases operation and maintenance costs and safety concerns; and 6. requires that plant operations be re-optimized that may take many years to accomplish.
Staff’s recommendation for the long-term is to terminate the NPDES permit and comply with the Time Schedule Order (TSO), yet to be approved by the Board of Directors, is to eliminate discharge to Magalia Reservoir by treating and recycling all process water back to the headworks of the treatment plant for potable reuse. As such, the District entered into a contract with LEE & RO, Inc., water and wastewater engineers of Sacramento, CA to assist in evaluating treatment alternatives, selecting the most feasible and cost effective process water (waste washwater) treatment system, and complete design. On May 30, 2012 staff first met with LEE & RO engineers to discuss a variety of possible treatment alternatives. The estimated project timeline was to obtain Board authorization to begin construction in 2013.
|Filename:||NPDES Permit Treatment Compliance Alternatives 6 13 12.pdf|
|Filetype:||pdf (Mime Type: application/pdf)|
|Created On:||07/27/2016 08:30|
|Last updated on:||08/01/2016 08:31|