Reclaimed Water Solution for Disposal CapacityVillage of Bald Head Island

2015 NC AWWA - WEA Annual Conference November 17, 2015

Bald Head IslandBrunswick County

ColumbusCounty

New HanoverCounty

BladenCounty

BrunswickCounty

PenderCounty

North Carolina

Bald Head Island

Bald Head Island

History & Project Drivers0.4 MGD SBR Wastewater Treatment Facility

- Original owner Bald Head Island Utilities (private)- Low pressure collection system- 3 High Rate Infiltration (HRI) Basins- HRI basins permitted at 0.8 MGD disposal capacity

WWTP

HRI Basin 3

HRI Basin 2

HRI Basin 1

History & Project DriversUtility Ownership Transferred to Village of Bald Head Island

- Transfer occurred late 90’s - Contractual obligation - island build-out capacity

WWTP

HRI Basin 3

HRI Basin 2

HRI Basin 1

HRI Basin 3 Issues

Lowest elevation on the islandProne to flooding Valve closed – unused for disposalDid not meet compliance or

review boundary rules

Bald Head Island Club (Golf Course) requested pond be removed from permit for drainage purposes

Village required alternate disposal to meet contractual obligation with developer

HRI Basin 3487,165 GPD

HRI Basin 2181,492 GPD

HRI Basin 1131,343 GPD

Original Disposal Capacities

Phase I - Interim

Phase I - Interim - Reshape Basin 1 & 2 (0.4 MGD)- Concurrent with GC Hole Rebuild- Permit Revised to “include” Pond 3 but stipulated must be compliant before activation

Provided “Breathing Room” to determine final solution

HRI Basin 3(inactive)

HRI Basin 275,295 GPD

HRI Basin 1324,705 GPD

Modified Disposal Capacities

Phase II – Final

Explore Alternatives for Disposal >0.4 MGD- Initial step: 0.8 MGD build-out reduced to 0.65 MGD- 0.65 MGD Need – 0.4 MGD HRIB = 0.25 MGD deficit

Alternatives Considered- Alt. A - Reconfigure/Reshape HRI Basin 3- Alt. B - Groundwater lowering system for basins 1 & 2- Alt. C - Convert storm drain pond(s) to HRI basins- Alt. D – Golf Course Reuse

Alternative A Reconfigure/Reshape HRI Basin 3

Advantages- Meet build-out capacity needs- Maintain current WWTP effluent limits

Disadvantages- Require reconfiguration of the golf hole

- Easement/Land Acquisition to meet Compliance and Review boundaries

- Challenges with freeboard, drainage due to low elevations

HRI Basin 3

Alternative B Groundwater Lowering System

HRI Basin 1 & 2 Advantages- Meet build-out utilizing current HRI Basins- Maintain current WWTP effluent limits

Disadvantages- Similar to HRI Basin 3 – challenges associated

with regulatory requirements compliance & review boundaries

- Ponds function as storm drain for the course and island

- Easement/Land Acquisition required for boundaries

HRI Basin 1

HRI Basin 2

Alternative C Convert Storm Drain Pond(s) to HRI Basins

Advantages- Build-out with additional HRI basin(s)- Maintain current WWTP effluent limits

Disadvantages- Significant infrastructure $$

- Impact to golf course

- Easement/Land Acquisition - O&M costs long term

- Flooding concerns

Alternative D - Recommended Golf Course Reuse

Advantages- Meets build-out needs- Public Acceptance- Desirable by all parties- Utilizes GC Irrigation System

Disadvantages- WWTP Effluent Limit Requirements

- 5-Day Upset Pond (land intensive)

- Wet Weather Storage (land intensive) - Village Water Supply Wells

- Club Irrigation Wells

Proposed Irrigation Areas (Existing GC System)

Dedicated Disposal Capacity- 250,000 GPD Reuse Non-Conjunctive- 400,000 GPD HRI Basin Capacity650,000 GPD Total Disposal Capacity

Total Reuse Capacity- 250,000 GPD Non-Conjunctive (Front 9)- 400,000 GPD Conjunctive (Back 9)- Normal Conditions – All effluent to GC

Irrigation/Production Well Conflicts

Non-Conjunctive Areas

Conjunctive Areas

HRI Basin 2

HRI Basin 1

Reclaimed Water Storage

Non-Conjunctive AreasConjunctive Areas

HRI Basin 2HRI Basin 1

GC IrrigationPond & PS

Reuse FMFrom WWTP

Utilize current irrigation pond PS system Unable to comply with DENR Setbacks

(property lines, homes, surface waters) House Bill 74 – allowed waivers for

setbacks and 0’ setbacks for reclaimed water storage ponds if effluent meets:

- 10 mg/l Total Nitrogen- 2 mg/l Total Phosphorous

Required plant modifications to meet TN/TP limits:- Mag Hydroxide Chem Feed- Alum Chem Feed- Carbon Source Chem

5-Day Upset Pond

Non-Conjunctive AreasConjunctive Areas

HRI Basin 2HRI Basin 1

GC IrrigationPond & PS

Reuse FMFrom WWTP

Utilize HRI Basins 1 & 2 for Upset Pond- 1.25 MGD Reqd. (0.25 MGD)- Maintain ambient level in each- Meets required volume

Reuse Force Main System Design- Valve/Metered to HRI 1 & 2- MOV for non-compliant reuse- Controlled by GC

Reclaimed WaterMeter/Control Valve

Proposed ProjectWWTP Improvements Blower Upgrades Magnesium Hydroxide Chemical Feed Aluminum Sulfate Chemical Feed Micro-C Chemical Feed Backup Chlorine Disinfection SCADA/Telemetry Modifications

Reuse Transmission System1,000 LF 10” Reuse Force MainReuse Meter & Control Valve VaultMeter & Control Valve Vaults HRI Basin 1 & 2SCADA/Telemetry Additions

Anticipated Completion Date May 2016

Village BHI WWTP

Questions?

Contact Information:

Tony Boahn, PE

tboahn@mckimcreed.com

910.343.1048