Process Water Recycle Project
This presentation was provided by the Regional Water Quality Control Board staff during the Public Hearing on June 8, 2016 regarding proposed increases to water service rates and charges under proposition 218, and includes the regulatory authority of the Regional Board, information about the National Pollutant Discharge Elimination System (NPDES) waste discharge permit and a Time Schedule Order, the problem with aluminum and dichlorobromomethane, regulatory compliance timeline for the Process Water Recycle project, and penalties. The presentation discusses the consequences of suspending the AECOM design and the Project implementation after January 1, 2018.
This Preliminary Design Report provides information needed for Paradise Irrigation District (PID) to review proposed upgrades to the surface water treatment plant located in Magalia, and then move forward with design.
On September 19, 2014, PID executed an agreement with AECOM for preliminary and final design of the Process Water Recycle Project and to assist in preparing bid documents for the construction of the Project. The scope of this agreement addressed preliminary design of the proposed Process Water Recycle Project using the lamella-plate settling process for treating waste washwater for recycling that was successfully demonstrated in the pilot study.
The primary objective of the Paradise Irrigation District Process Water Recycle Project is to achieve regulatory compliance with National Pollution Discharge Elimination System (NPDES) permit conditions by eliminating the continuous surface water discharge of waste washwater from the treatment plant to the Magalia Reservoir. Improvements to the existing water treatment plant are proposed to effectively recycle the waste wash water for potable reuse within the treatment plant. As secondary objectives, several improvements are proposed to improve reliability by renewing, replacing or relocating existing facilities, completing major repairs or modifications to correct existing problems, and making provisions for future planned facilities.
The Paradise Irrigation District (PID) water treatment plant (WTP) requires new waste washwater processing capabilities because of increased stringency in NPDES discharge regulations. Waste washwater from the plant includes upflow clarifier flush water, filter backwash water, and filter-to-waste water. This report summarizes testing conducted at the WTP to demonstrate the lamella plate settling / thickening process. The pilot testing demonstrated that the process performs well for the application of treating waste washwater for recycling at the PID WTP.
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This Life Cycle Cost Analysis Report presents a life cycle cost comparison of two Alternatives for the Process Water Recycle Project. The two alternatives are 1. Mechanical Settling; and 2. Constructed Wetlands
Lee & Ro completed an Alternatives Evaluation Report in March 2014 that examined alternatives to upgrade the water treatment plant (WTP) waste washwater collection and holding ponds to return the settled water to the inlet to the WTP for blending with its raw water supply.
Brown and Caldwell was retained by Lee & Ro, Inc. in December 2013 to evaluate a constructed wetlands alternative for the treatment and recycling of waste washwater from Paradise Irrigation District’s (PID) water treatment plant. This report provides an evaluation of a wetlands alternative that PID will consider along with the other alternatives developed by Lee & Ro.
The purpose of this Alternatives Evaluation Report is to develop and analyze alternatives for waste washwater treatment so that PID can: 1. stop the discharge of decanted washwater to Magalia Reservoir; 2. not renew the permit that regulates the discharge of decant water to the Reservoir and avoid the costs associated with the permit; and 3. recycle treated washwater back to the WTP thereby conserving a significant portion of the District’s raw water supply.
This presentation updates the Board of Directors regarding progress to determine alternatives that terminate the NPDES permit by installing an additional treatment system for the plant’s process water (i.e. waste washwater). The new system will separate the process water liquid from the solids. The liquid will be returned continuously to the head of the treatment plant for reuse. The solids will be thickened and dried periodically and disposed of at the local landfill. The presentation discusses the components and schematics for the feasible alternatives being considered, construction costs for each alternative, changes to the scope and cost of the project, and schedule.
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.