Wastewater, a Resource not a Burden!
Flemming B Møller
Senior Technical Advisor,
Project Manager
Flemming B Moller
• Senior Technical Advisor
• Project Manager
• Marine Engineer and experienced WWTP Operations Manager
Aarhus Water
•
•
•
•
Volume of abstracted, treated and distributed drinking water
Volume of processed wastewater
Number of employees
Annual budget
Our vision is to be a leader amongst water companies
3957 M gallons/year
7915 M gallons/year
209
146 mill USD/year
Come learn more about...
•
•
Net Zero WWT Plants, is that real?
How WWT anaerobic digesters can create
revenue streams
A WRP consists of blocks,
we know how to put them
together !
Agenda.
•
What steps have we taken to make the energy producing WWTP in
Aarhus a reality?
• Reduction of energy
• Production of energy
•
Struvite - From problem to resource
•
Best Practices US/DK
First Step for Aarhus Vand – Energy Management
Our consumption of electricity used to be large at our WWTP.
In the fall of 2009, we were energy certified according to the
European DS 2403 standard in our efforts to reduce our
energy consumption.
Reality – where Does the Energy Go
Electrical Power Consumption
Aeration 37 %
6
Energy Neutrality And Beyond
The Development in electricy
consumption – Marselisborg RA
Average 24 – hour electricity consumption
Total reduction achieved 27%
New Sandfilter
+ 1000 kWh/d
Process Optimizing
New Blower
Energy Balance - Power Self Sufficiency %
%
Introduction – Marselisborg WWTP
Energy Savings – Power Production
Optimization of N-removal
and Power Consumption
Set Point
%
DO
Ammonium
Nitrate
HV Turbo blowers - 1992
•
•
•
•
Reduction in electricity
consumption : 300,000 kWh/year
CO2-reduction: 153 tons/year
Construction costs : US$ 270.000
ROI: 4-5 years
Key Figures
ABS HST Compressor
•
•
•
•
•
Type: HST 40-350-1-L-4
Airflow 5000-16000 Nm3/h
Power 350 Kw
Pressure 430 mbar
Water Depth 4 meter
15
Specific Energy Consumption – New Blower (HST
Compressor)
0,014 kWh/Nm3
Kapselblæsere,
Nøgletal
(Egå,
og
Åby): 0,019-0,023
Positive displacement
blower, Key
figures (Egå,
Viby Viby
og Åby):
0,019-0,023
kWh/Nm3
kWh/Nm3
Sludge Balances and Control of Aerobic Sludge Age
Increasing Co-generation of Electricity/ Excess Heat from Biogas
Replacement of 3 old gas engines with two high efficiency - 2 pcs 250 kW - CHP units
• Construction costs : 1,382,000 US$
CO2-reduction: 426 tons/year
• ROI: 3 years
• Construction period: 2010-12
• Electricity production (additional
production): approx 1 mio kWh/year
•
•
•
18
Power efficiency
38-39%
Excess heat efficiency 50-55%
Total efficiency
88-94%
Surplus Heat from Biogas – Marselisborg WWTP
Construction costs:
US$ 180,000
Annual Income (sale):
US$ 71,000
ROI:
< 1 year
CO2 Reduction:
322 ton/year
Excess heat sales of 2.5 GWh/year (2013)
19
Struvite - From Problem to Ressource
Recovery of a valuable phosphorous resource
The problem
• Gray irritating material in pipes, digesters
and sludge treatment processes
Mg2+
+ HPO42-+
NH4+
+ 6H2O → MgNH4PO4,6H2O + H+
magnesium +phosphorous +ammonium + water →
The resource
12.6 % P, 5.6 % N, 10 % Mg
a premium fertilizer!
struvite + acid
Full Scale Struvite Plant Aaby WWTP
Capacity of plant:
•Capacity 2600 gallons reject/h
•3-400 kg Struvite/day
•2 reactors
Benefits of P-recovery:
•Fewer problems with dewatering
equipment
•Savings on chemicals for P-removal in
main process
•Less sludge production.
•Less polymer consumption
•Less Electricity for nitrification (less
NH4)
•More biogas
•Increase in plant capacity
•ROI 5-7 years
21
Where are we going?
Consulate General of
Denmark in Chicago
US - WWTP
Our focus
• Sharing and exchanging ”best practices” and knowledge on technical
solutions as related to the entire Water Cycle.
• Looking for US Champions who want to enter into a mutual knowledge
sharing exchange and have an ongoing working relationship with our Water
Specialist/WTA
Next step
• Workshop at Downers Grove, Nick Maninga on January 27, 2015
• Fact finding trip to Denmark
Wastewater, a Resource not a Burden!
Thank you for your attention.