ASHRAEWashington, DC Chapter

Title: Best Practices for Water Reuse System DesignDate: December 16, 2016Presenter: Jonathan Garrick, Project Manager, Aquanomix

OVERVIEW

• Water reuse systems are showing up in increasing numbers of

commercial projects, especially when end uses are for indoor

nonpotable applications.

• Benefits of Water Reuse

• Offset utility costs

• Sustainability

• Design Objectives and Best Practices

• What you need to know when designing a water reuse system

WATER REUSE

WATER REUSE

• Rainwater• Greywater• Stormwater• Foundation water• Steam condensate• Air handler condensate• Process water

WATER REUSE SYSTEMSWater reuse technology can be retrofitted intoexisting buildings or incorporated into newbuilding design using:

Smithsonian National Museum of African American History & Culture

George Washington UniversityScience and Engineering Hall

New Campus for Cornell University on Roosevelt Island, NYTransBay Transit, San Francisco

Gateway Village: Financial, Residential, Data Center

WATER REUSEGEORGE WASHINGTON UNIVERSITY SCIENCE AND ENGINEERING HALL

� 14-story modern research hub that seeks to inspire a new generation of faculty, researchers and students with its wet and dry labs, collaborative teaching areas, lounges and aquatic suite

� Three-story bay was built for large-scale experiments, as well as an imaging facility and a facility for nanotechnology fabrication

� 8 of the floors are above grade, 2 below for programming and 4 below for parking

WATER REUSE

DETAILS:

� Facility Type: Education� Building Size: 700,000 square feet� Cistern Size: 42,000-gallon� System Size: 60 GPM filtration and pumping station� Water Source: Rainwater from the roof� Water End Use: Toilet flushing� Sustainability: Registered with USGBC and are pursuing LEED Silver

GEORGE WASHINGTON UNIVERSITY SCIENCE AND ENGINEERING HALL

OUTCOME: Rain from the roof drains into a 42,000-gallon cistern to be filtered and used to flush toilets, saving roughly 850,000 gallons of water per year

WATER REUSEMARRIOTT MARQUIS, WASHINGTON D.C.

OVERVIEW:

The Washington Marriot Marquis is pursuing LEED® Silver.

An all-glass entrance, skylights, and structural glass curtain walls reduce the need for electric lighting.

Local engineer designed specialized MEP systems to support the hotel’s fitness center, ballrooms, meeting rooms, 15-story atrium, full smoke control system, and water recovery.

WATER REUSE

DETAILS:

� Building Size: 975,000 sq. ft.

� Cistern Size: 42,000-gallon

� System Size: 60 GPM treatment & pumping station

� Water Source: Rainwater from roof

� End-Use: Makeup for cooling tower and irrigation

� Completed: 2014

MARRIOTT MARQUIS, WASHINGTON D.C.

WATER REUSESMITHSONIAN NATIONAL MUSEUM OF AFRICAN AMERICAN HISTORY AND CULTURE

Overview:• $500 million, 350,000 sq. ft. project• Currently under construction • National Mall in Washington, D.C.

• five-acre tract adjacent to the Washington Monument• deepest museum on the Mall

Construction:• Excavators dug 80 feet below street level to lay the foundation at a very low point on the water table where all the

surrounding groundwater drains to that point,• Put 27.78 pounds per square inch on the walls• 85 gallons per minute of water pumped out every day

WATER REUSESMITHSONIAN NATIONAL MUSEUM OF AFRICAN AMERICAN HISTORY AND CULTURE

WATER REUSESMITHSONIAN NATIONAL MUSEUM OF AFRICAN AMERICAN HISTORY AND CULTURE

DETAILS:� Cistern Size: 100,000 gallon underground

� System Size: 15,000 gallon day tank, 100 GPM filtration pumping station, 150 GPM triplex booster pump

� Water Source: Groundwater, rainwater, stormwater

� End Use: Toilet flushing, irrigation use, fountain makeup

� Date Opening: Late 2016

� Total Cost: $500 million

Objective: To revitalize Charlotte’s historic Third Ward by developing a 15-acre mixed-use site designed to bring business, retail, restaurants, new residents and visitors to the area.

• $300 million multi use project• 1.5 million sq. ft. high-tech office space + data center• 125,000 sq. ft. retail space• 1,000 residential units

WATER REUSEGATEWAY VILLAGE – CHARLOTTE, NC

WATER REUSE

Job: Retrofit a foundation dewatering system with a custom designed-water reuse system to help achieve LEED® Gold status and save millions of gallons of city water for the cooling towers

� Water Source: Contaminated foundation water

� Water End Use: Cooling tower makeup

� 3+ million gallons of water saved annually = 15+ million gallons saved to date

� 4.25 years project payback

� Eliminated potable city water for cooling tower makeup

GATEWAY VILLAGE, CHARLOTTE, NC

DESIGN OBJECTIVES

• Process Effectiveness• Successful Water Treatment• Reliability

• Mechanical Effectiveness• Equipment Sizing• Maintenance

• Cost Effectiveness

• Regulatory Compliance

CONSIDER THE SOURCE

• Potential Sources• Rainwater• Graywater• Stormwater• Foundation Water• Steam Condensate• Air handler condensate• Process Water

• Potential Uses• Irrigation• Car Wash / Truck Wash• Toilet Flushing• Laundry Facilities• Cooling Tower Makeup

WATER TREATMENT TOOLS

• Mechanical Purification: removing suspended particles• Prefilters• Centrifugal Separators• Auto-clean Filters• Polishing Filters

• Chemical Purification• Precipitation• Media Filters – removing dissolved constituents• UV disinfection• Chemical residual disinfection

CISTERN SIZING: SUPPLY AND DEMAND

• Can be governed by stormwater authority• Supply

• Rainwater and Stormwater

• Groundwater• Condensate

• Demand• Daily Averages• Peak Usage

CISTERN INSTALLATION LOCATION?

PRE-FILTER SELECTION

• Considerations:• Sizing: Area (sqft)• Installation Location• # of outlets• Retention vs. Waste• Presence of FOG

• Settling:• Dual Vortex Separator

• 100% recovery• Single Inlet/Outlet• Hydrocarbon removal• May allow more solids

• Oil/Water Separator

oldcastlestormwater.com

• Screening:• Vortex Filter

• Up to 30,000 sqft• 85-90% recovery

• Cascade Filter• Up to 16,000 sqft• 95% recovery

• Basket Filter• Up to 12,000 sqft• 100 % recovery

DISINFECTION

• Ultraviolet (UV) light provides rapid, effective inactivation of microorganisms (bacteria, viruses, and protozoa) through a physical process.

• Non-Chemical process and does not leave any residuals

• Sizing:• UV dose - 30 mJ/cm2 (average) typical for reuse applications• Transmittance (UVT) – function of the water (turbidity, water chemistry)

• ASHRAE 188• <5 mJ/cm2 required to inactivate most harmful bacteria (legionella, e. coli, coliform)

• Intensity Monitoring• Sleeve Cleaning• Lamp replacement

DISINFECTION

• Chemical Residual Disinfection (Biocides)• Deactivates biological elements by lysing the cell wall• Lysis (/ˈlaɪsɪs/; Greek λύσις lýsis, "a loosing" from λύειν lýein, "to unbind") refers to the breaking

down of the membrane of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity.

• Ozone, Chlorine

• Metering pump for dosing

• Monitoring Probes and Analyzers necessary

CIRCULATION

• In the absence of system demand, reclaimed water can be circulated back to the storage tank to continuously maintain or improve overall water quality

• In stagnant conditions, bacteria levels can double every thirty minutes

• Use 3-way diverting valve to cycle between system demand and re-circulation

• Turnover Schedule • Secondary disinfection circulation should

be considered for day tanks depending on usage

MAKE-UP WATER

• Potable or non-potable municipal water used to supplement reclaimed water when the demand exceeds the supply.

• Makeup water supply should consider the following situations:• Start-up, pre-commissioning activities• System Maintenance• Equipment Failure• Loss of Power

MECHANICAL DESIGN

• Pipe Sizing: typical 6-8 ft/sec for PVC

• Isolation Valves

• Maintenance Clearances• UV lamp and sleeve removal• Cartridge filter vs. bag filter removal

• Filter Flush Drain location

• Day Tank Overflow

• Room location – wet room

MECHANICAL DESIGN

DAY TANK NECESSARY?

• Intermediate Storage Tank for pressure boosting or surge capacity

• Peak Flow vs. Average Flow• Pressure rating of treatment skid vs. required head for system

• Air Gap

• Day Tank Sizing Considerations• Space requirements• Peak flow and duration• Actuator Open/Close time

DAY TANK NECESSARY?

Case Study – Elementary School reuse for toilet flushing• Option 1 – No Day Tank

• 40K gallon storage tank and level controls• 2 submersible pumps, 100 gpm• 200 gpm Treatment skid (3” piping and components, Separator, 4 x Bag Filters, UV)• $206 K

• Option 2 – With Day Tank• 40K gallon storage tank and level controls• 2 submersible pumps, 40 gpm• 40 gpm Treatment skid (1.5” piping and components, Separator, Bag Filter, UV)• 1000 gallon polyethylene tank and level controls• 100 gpm Duplex booster pump• $167 K

SYSTEM INTEGRATION

• How does the water reuse system communicate with overall building management system?• Call for water?• Stormwater Management• Domestic Water Make-up• Maintenance Alarms• Trending Operating Parameters

• Integration through commissioning

SYSTEM INTEGRATION

WATER QUALITY MONITORING

• Depends on Source and Supply• Typical Sensors:

• PH• ORP• Conductivity

• Cooling tower operation dependent on specific water quality• Potential to adjust water treatment protocol• Target Cycles of Concentration

LEVEL TRANSMITTER INSTALLATION

• Mounting location• dependent on tank geometry• accessibility • presence of condensation?

• Standpipe - dampen turbulence, separate surface foam from the point of measurement or increase performance in heavy vapor.

• 3” pipe • bottom of the pipe should remain submerged at all times to prevent foam from entering the pipe. • Cut the bottom end of the pipe at 45° and drill a 1/4” pressure equalization hole in the dead band.

LESSONS LEARNED

• Level Transmitter Installation• Day Tank Overflow• Drain Location• Maintenance Clearances/Allowances• System integration is critical to successful operation

• ICC Rainwater Harvesting Systems Standard• Supports existing codes and design requirements for major types of water storage

tanks, system sizing methods, water quality criteria, storm water management and automatic fire sprinkler system integration.

Thank you.