Water Treatment Technology that Works for Megacities in need of Efficient Wastewater

Treatment, Recycling, Soil Remediation and Food Production Resources

Using Engineered Natural Systems to Treat Water

Sarah Meyland, MS, JDDirector

Center for Water Resources Management at NYIT

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Wetlands: Nature’s Kidneys

2Bacteria and plants have cleaned water for over 2 billion years.

Natural Wetlands as Water Treatment Systems

• Arcata, California• Population: 17,600• On Humboldt Bay• 90 miles from Oregon• 300 miles from San

Francisco• Humboldt State Univ.

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Arcata Marsh: Wastewater Treatment, Interpretive Center and Wildlife

Sanctuary• Size of treatment area is

about 160+ acres in the salt marshes of Humboldt Bay; • The constructed wetlands

process 2.3 MGD. • Treatment plant steps:• Primary Treatment• Secondary Treatment• Tertiary Treatment• Disinfection

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Copying Nature with Constructed Treatment Wetlands

• There are many versions of how to copy the natural treatment process of wetlands.• Dr. John Todd, a leading proponent of

constructed wetlands; (President, John Todd Ecological Design, Inc.)• U.S. EPA has supported a number of pilot

systems for industrial & municipal use. • “Living Machines” is a well-known EPA-

approach.• Others include: Solar Aquatics, Solar Ponds, • Roux System: Enhanced Subsurface Flow

(SSF) CTW 5

NYIT Project – Old Westbury Campus

• NYIT planning to build on-campus housing.• The sewage

treatment system will be updated.• Project offers an

opportunity for a new approach to sewage treatment. 6

Improving on Current System• NYIT uses a combination of

septic tanks and an Oxidation Ditch system, with two treatment trains. • Flow to the plant averages

22,000 gallons per day currently.• Treatment quality is

substandard for nitrates.• When all new construction is

completed, average flow could go up to 70 – 85,000 gpd. 7

Replacing Outdated System• Treatment Plant built in 1968.

• 2 Symmetrical Oxidation Ditches

• One Ditch inactive.

• Each ditch had volume of 205,000 gallons. (180 ft x 80 ft)

• One Ditch converted to 2 aeration tanks and 2 anoxic tanks - - 4 stage activated sludge treatment process in 1996.

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Original NYIT System

Considered Alternative Systems

• The Living Machine• Closed Loop System• Plant-based treatment• Plants, fish, bacteria,

snails, water bugs, etc.

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Enhanced Subsurface FlowConstructed Treatment Wetland

• Green Technology: low power needs, no chemicals, self-sustaining, low maintenance, scalable, exceeds discharge quality standards, requires less space, passive system.• Features:• Site is excavated and Subsurface Aeration System

installed in lined basin (cell).• Bubble Diffusers inside perforated contactor chamber.• Buried in Gravel Treatment Media that supports bacterial

growth.• Covered with soil to support wetland plants with good

root development.• Site is bermed to retain water in basin.

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Enhanced Subsurface FlowConstructed Treatment Wetlands

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Aeration System Close-up

12Aeration System creates highly aerobic condition to give consistent year round treatment performance, even in cold climates and reduces

retention time.

Capabilities of SSF CTWs• Removal of Pollutants including:• Organic Substances• Nutrients• Heavy Metals• Toxic Chemicals: PAH, PCBs, BTEX, • Suspended and Colloidal Materials• Pathogens

• Design Options:• Free Water Surface Systems – Marsh-pond-meadow Sequences• Subsurface Flow Systems – Engineered cells containing gravel,

soil and/or sand treatment media.• Enhanced Subsurface Flow Systems – Adds subsurface aeration

system to increase microbiological activity and removal. 13

BTEX Remediation in Rhode Island

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Groundwater and stream water is channeled into a series of cells that removed the BTEX before it reaches a larger stream system. This was at a refinery site in Rhode Island, USA.

Wastewater Treatment Capabilities

• Sedimentation and filtration removes TSS.

• Microbial degradation and removal of TSS, BOD and nitrogen.

• Microbial destruction of pathogens.

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Performance Examples of Constructed Wetland Systems

1. BOD before treatment = 250 mg/L

2. TSS before = 160 mg/L3. TKN before = 40 mg/L4. NH3 before = 50 mg/L

5. NO3 before = 0 mg/L

6. TP before = 7 mg/L

1. BOD after treatment = < 10 mg/L

2. TSS after = 10 mg/L3. TKN after = 10 mg/L4. NH3 after = 2 mg/L

5. NO3 after = < 5 mg/L

6. TP after = < 5 mg/L

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Performance of SSF CTWBOD Removal Before (RED)

After (GREEN)

NH3 – NitrogenBefore (RED)

After (GREEN) 17

Aeration Off OFF

Urban Environment Applications

• In cities, CTWs can be placed into existing sewer collection systems to accept part of wastewater flow prior to reaching conventional STP. (Small Footprint)• Reduce/eliminate overflows and treat

stormwater. • Treat contaminated surface water and

groundwater.• Treat contaminated soil.• Be recycled for uses such as urban

farming (vertical farming) or cooling water/grey water.

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Questions

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System Requirements• Cells fit into sites that

are 50% smaller than other systems.• Demonstration system

treats flow = 10,000 gpd.• System is expandable.• Provides tertiary

treatment.• Affordable.• Sustainable, low carbon

footprint; low energy use.

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Looking South

Looking North

Research Potential of System • CTW compatible with existing treatment at NYIT,

using it to perform solids removal.

• Similar systems have received NYS SPDES discharge permits.

• Systems can be used to research different pollutants, different micro-biological cultures, different system design questions or to address other issues such as:• Stormwater treatment• Heavy metal removal• Toxic chemical removal 21