A Tale of Two Plants: How Combining WWTP and WTP Improvements in Reidsville is Setting the Stage for the Future Kevin Irby, P.E. Kevin Eason, P.E. 2015 Annual Conference Raleigh, NC

A Fresh Start Creates Exciting Opportunities New Public Works Director 2008 New City Manager New Council Member Rate increase Took back ownership of facilities New WTP Superintendent

A Tale of Two Plants Wastewater Treatment Facility Aged deteriorated infrastructure (1956) Highly O&M and chemical intensive Significant sludge hauling costs Capital improvements required Water Treatment Facility Newer infrastructure Subject to raw water variability Significant public visibility and concern Operational and minor capital improvements required

WEEKLY AVERAGES AND LIMITS PLOTTED Plant has Performed Well with Respect to CBOD, TSS, and Ammonia Effluent Limits WEEKLY AVERAGES AND LIMITS PLOTTED

Areas of Evaluation/Optimization at the WWTP Nutrient Removal Biosolids Handling & Disposal Chronic Effluent Toxicity Foam Mitigation and Scum Handling Electrical Power Distribution System Several Basins had been “repurposed” over the years

WWTP Electrical System Issues Voltage stability - dimming lights when starting equipment Downtime due to breaker trips Service is currently at maxed out Code & safety issues NEC code violations – cables undersized Aged equipment – in poor condition Reliability – single point of failure Revise graphic to match numbers in Final Report Electrical improvements required concurrent with solids handling improvements

BNR Used For T-P compliance Evaluating Impacts of BNR Sidestreams contribute to upset of nitrification due to aeration capacity Filter backwash Gravity thickener effluent Sludge Holding Tank Supernatant RAS discharge location Insufficient Mixing in Anaerobic/Anoxic Zone Anaerobic/Anoxic Zone not baffled

Sludge Hauling Historically Has Been A Substantial Cost to Reidsville Contract hauling and land apply Over $670,000 was spent for sludge hauling in 2011 13,400,000 gallons hauled Peak year was 2008: over $700,000 9,600,000 gallons hauled (required to haul further distances) Approximately $5MM since 2006

Sludge Hauling Costs are Related to the Concentration of Sludge ~$130,000/yr savings

Overview of WWTP Improvements Solids Processing Improvements New Solids Thickening New Solids Dewatering Additional Aerobic Digester Capacity New Dewatered Cake Storage PAC Addition Improvements Upgrades to Electrical Service and Distribution Operations Building Roof Replacement Repaving Plant Roads

Recommended Thickening and Dewatering Option

Rotary Drum Thickener and Screw Press ~0.5% to ~3.5% (2 units) ~3.5% to ~20% (1 unit)

WWTP Recommended Site Plan

WTP Improvements Project ADD WTP City had experienced a history of discolored water complaints

Reidsville WTP Schematic

Data Evaluation: Discolored Water Complaints

Executive Summary of Water Quality Issues Widespread – Raw water/WTP is the source Customer complaints are driven by multiple factors Varying raw water quality Manual WTP operations Start/stop WTP operations Clearwell residual build-up Recommendations Operational improvements WTP upgrades

Implement Multi-barrier Approach to Address Discolored Water Issues Lake Aeration System Replacement Raw Water Flow Control Contact Tank Addition Chemical Metering Pump Flow Control Improvements Process Monitoring Upgrades SCADA System Upgrades

WTP Improvements – Proposed Process Flow Diagram CFE TURBIDIMETER METERS FOR pH and Cl2

WTP Recommended Site Plan

Additional Improvements Identified During Preliminary Engineer Review WWTP WTP Replace aeration system in Aeration Basin No. 1 Install new drive on finished water pump Clean drying beds Replace filter media Demolish abandoned trickling filter Improve raw water metering Install influent flow metering Improve finished water metering SCADA system upgrade Install new drive on finished water pump (>$17K per trip on existing)

Due to Significance of Investment City Opted to Combine into a Single Construction Effort Estimated $250,000-$300,000 saving on contractors effort Estimated $50,000 savings on engineers effort Significant saving of City staff time and effort Allotted a State zero interest loan of $15,000,000 for WWTP work only

How’d We Do? Expected Completion February 2016 Engineers March 2013 OPCC was $17,210,000 for both WWTP and WTP work. 6 Bids were opened on September 30, 2013 Low bid was for $16,476,000 WWTP - $11,948,000 WTP - $4,028,000 Contingency - $500,000 High bid was $18,185,000 Notice to Proceed was issued January 6, 2014 Expected Completion February 2016

WWTP Action Photos Blower Air Intakes Rotary drum thickener Screw Press Solids Handling Building

WWTP Action Photos New Diffuser Grid Inside Aeration Basin Fiberglass Pipe Inside New Digesters New Diffuser Grid Inside Aeration Basin

WTP Action Shots Raw water bypass piping Raw water venture vault

Questions?