1. Ken Lewis
GES graduate
Working at HNEI 4 yrs
Water, Energy, Food Nexus
Graduate MGeo Fall ‘16
Seeking Employment in Water
Reclamation/Remediation/Reuse

2. COMBINED ANAEROBIC-AEROBIC
TREATMENT OF HIGH STRENGTH
ACIDIC WASTEWATER
Presented by Ken Lewis
High Rate Anaerobic – Aerobic Digestion (HRAAD)
Grease Trap Waste Wastewater (GTWW)

3. Introduction
Average Hawaiian Home
uses 150 gallons of water per day per person
99% comes from groundwater
95% is ‘treated’ and discharged near-shore
Water is wasted
Environmental/Economic Impact

4. Biological processes can be cost effective
• energy consumption and chemical usage
Conventional biological wastewater treatment
• energy intensive aerated systems
• economic and environmental impact
• long-term sustainability questionable
HRAAD
Low-energy anaerobic treatment is placed in-line with
naturally aerobic systems. Chemical usage is addressed,
a bio-active sediment filter is employed, and the treated
effluent (R1) is used to grow crops.

5. Developed
in Lab
Tested at
Scale
15L HRRAD model. POST 06, 2015-16

6. GTWW is a Waste Product of Bio-Diesel Production
Grease Interceptor

7. Goals:
 Low HRT (< 2 d)
 Reduce BOD5 and TSS to EPA
Standards (30g L-1)
 Reduce Tipping Fees and
Environmental Impact
 Produce CH4 near theoretical limit
 Eliminate Basic Addition
 Reuse Treated Effluent

8. Methods:

9. Elimination of Basic Addition
NaOH is dosed into the hydrolysis reactor to
offset acids introduced with the feed.
Once the methanogenic communities are
established in the anaerobic reactor,
properly timed recycling of digestion
products from the anaerobic column to the
hydrolysis reactor deliver abundant hydroxyl
ions eliminating the need for NaOH addition.
Achieved in 75 days
Results:

11. COD Reduction Profile

14. Flow
UV Sterilizer
Aeroponics
pump
Nutrient Rich R1 Water for Reuse
Anaerobic digestion converts organic C to CH4
Nutrients remain
Harmful NH4
+ and NH3 are converted to NO3
- in the TF
R2 R1

15. Food, Fuel, Ornamental Crops
Treated water has
nutrient profile
suitable for crop
production

16. HRRAD addresses scalable point-source
wastewater treatment and provides
energy rich bio-gas and nutrient rich
reuse water while meeting EPA req’s
and reducing environment/economic
impacts. Reuse water is further polished
in constructed wetlands.

17. • Scalable point-source wastewater
treatment.
• Anaerobic digestion provides bio-gas
for local energy needs and nutrient-
rich reuse water.
• Unused reuse water can be
discharged to sewer, surface or
underground waters.
• Research continues with advanced
oxidative processes for degradation
of contaminants of emerging
concern (CECS).
Conclusions:

18. Questions
What is a constructed wetland?
What is aeroponics? How do plant roots clean water?
Are foods crops grown with
reuse water safe to eat?
Can reuse water damage soils?