A look at the City of Lima, Ohio, and its WWTP Master Plan Update. Presented by Russell Bales during AEP Ohio's Water/Waste Water Customer Seminar held at Zane State in Zanesville, Ohio.

1. Energy Workshop
December 19, 2012
1

2.  Introduction Wordelman
 Overview of Energy Use
 Electric Lowery
 Natural Gas/Digester Gas Teague
 Alternatives for Generation
and Savings Wordelman
 Conclusion Wordelman
2

3.  Understand current usage
 Electrical
 Natural gas/digester gas
 Initial screening ideas
3

4.  Electrical
 Total purchased
 Operating scenarios
 Natural gas
 Total purchased
 Digester gas
 Digester gas used flowmeter
 Digester gas produced flowmeter
4

5. 5

6. 6
$0
$10,000
$20,000
$30,000
$40,000
$50,000
$60,000
0
100000
200000
300000
400000
500000
600000
700000
800000
7/1/2009
8/1/2009
9/1/2009
10/1/2009
11/1/2009
12/1/2009
1/1/2010
2/1/2010
3/1/2010
4/1/2010
5/1/2010
6/1/2010
7/1/2010
8/1/2010
9/1/2010
10/1/2010
11/1/2010
12/1/2010
1/1/2011
2/1/2011
3/1/2011
4/1/2011
5/1/2011
6/1/2011
7/1/2011
8/1/2011
9/1/2011
10/1/2011
11/1/2011
12/1/2011
1/1/2012
2/1/2012
3/1/2012
4/1/2012
5/1/2012
6/1/2012
MonthlyElectricalCost$
kWHour
Lima WWTP Monthly Electrical Purchase
kWhr per Month
Electrcial Cost

7. 7
300000
350000
400000
450000
500000
550000
600000
650000
700000
750000
800000
7/1/2009
8/1/2009
9/1/2009
10/1/2009
11/1/2009
12/1/2009
1/1/2010
2/1/2010
3/1/2010
4/1/2010
5/1/2010
6/1/2010
7/1/2010
8/1/2010
9/1/2010
10/1/2010
11/1/2010
12/1/2010
1/1/2011
2/1/2011
3/1/2011
4/1/2011
5/1/2011
6/1/2011
7/1/2011
8/1/2011
9/1/2011
10/1/2011
11/1/2011
12/1/2011
1/1/2012
2/1/2012
3/1/2012
4/1/2012
5/1/2012
6/1/2012
kWHour
Lima WWTP Electricity Purchased vs. Consumed
Benefit of Microturbines
Purchased
Consumed

8.  Capstone C65 microturbines consume
approximately 22 cfm of biogas
 Each turbine produces 60 kw electricity and
250,000 BTU/hr heat
 At current energy prices this is worth about
$43,000 annually
 Use of the same amount of biogas for boiler
heating only would be worth approximately
$27,000 annually
 Each unit can deliver ~ 8% of the plant’s electrical
demand
8

9. 9
0
100
200
300
400
500
600
700
800
900
0
100000
200000
300000
400000
500000
600000
700000
800000
7/1/2009
8/1/2009
9/1/2009
10/1/2009
11/1/2009
12/1/2009
1/1/2010
2/1/2010
3/1/2010
4/1/2010
5/1/2010
6/1/2010
7/1/2010
8/1/2010
9/1/2010
10/1/2010
11/1/2010
12/1/2010
1/1/2011
2/1/2011
3/1/2011
4/1/2011
5/1/2011
6/1/2011
7/1/2011
8/1/2011
9/1/2011
10/1/2011
11/1/2011
12/1/2011
1/1/2012
2/1/2012
3/1/2012
4/1/2012
5/1/2012
6/1/2012
AirflowMCUFandMillionGallonsTreated
kWHour
Lima WWTP Monthly Electrical Purchased
Monthly kWhr
Monthly Total Airflow MCUF
Million Gallons Treated

10. 10
0
10
20
30
40
50
60
70
80
90
0
100000
200000
300000
400000
500000
600000
700000
800000
7/1/2009
8/1/2009
9/1/2009
10/1/2009
11/1/2009
12/1/2009
1/1/2010
2/1/2010
3/1/2010
4/1/2010
5/1/2010
6/1/2010
7/1/2010
8/1/2010
9/1/2010
10/1/2010
11/1/2010
12/1/2010
1/1/2011
2/1/2011
3/1/2011
4/1/2011
5/1/2011
6/1/2011
7/1/2011
8/1/2011
9/1/2011
10/1/2011
11/1/2011
12/1/2011
1/1/2012
2/1/2012
3/1/2012
4/1/2012
5/1/2012
6/1/2012
AverageMonthlyTemperatureF.
kWHour
Lima WWTP Monthly Electrical Purchased
Monthly kWhr
Monthly Temperature

11. 11
Screening
0.1% Grit Removal
0.2% Baxter Street
8.1%
Primary Tanks
1.5%
Aeration
35.5%
Sludge Pumps
8.4%
Final Clarifiers
0.5%
Nitrification
14.6%
Disinfection
0.2%
Digestion
9.5%
Dewatering
1.6%
Stabilization
0.1%
Admin Building
0.5%
Miscellaneous
19.3%
Breakdown of Energy Consumption
%

12. 12
Screening
587 Grit Removal
1,074 Baxter Street
45,388
Primary Tanks
8,212
Aeration
198,734
Sludge Pumps
46,805
Final Clarifiers
2,576
Nitrification
81,735
Disinfection
850
Digestion
52,866
Dewatering
8,765
Stabalization
572
Admin Building
2,928
Miscellaneous
108,121
Stabilization Energy Consumption
(kWhr / Month)

13. 13
Screening, $39 Grit Removal, $72
Baxter Street, $3,041
Primary Tanks, $550
Aeration, $13,315
Sludge Pumps, $3,136Final Clarifiers, $173
Nitrification, $5,476
Disinfection, $57
Digestion, $3,542
Dewatering, $587
Stabalization, $38
Admin Building, $196
Miscellaneous, $7,244
Breakdown of Energy Consumption
($ / Month)

14. 14
0
500
1,000
1,500
2,000
2,500
3,000
3,500
0 20 40 60 80 100 120
TypicalEnergyConsumption(kWh/MillionGallon)
Capacity (mgd)
Basic Activated Sludge
Advanced Wastewater
Treatment
Advance Wastewater
Treatment With Nitrification
Chart Adapted from the Electric Power Research Institute Water & Sustainability (Volume 4): U.S.
Electricity Consumption for Water Supply
& Treatment - The Next Half Century (March 2002)
Lima Electrical Consumption
~1450 kwhr/MG

15. 15
Lima ~19,000 kwhr/day

16. 16
Typical Daily Electric
Consumption 10 mgd WWTP
per Process* kwhr/day Lima Consumption
Influent Pumping 1402 1513 (Baxter St.)
Screening 2 20
Aerated Grit 134 36 (Not Aerated)
Primary Settling 155 274
Diffused Air Aeration 5320 6624
Secondary Settling 155 86
Chlorination 27 28
Anaerobic Digestion 1400 1762
Belt Press Dewatering 384 292
* The Electric Power Research Institute Water & Sustainability (Volume 4)

17.  Current electrical rate including all
charges is approximately $0.065/kWhr
17

18. AEO 2012
Reference Case EVA IHSGI Inforum
2010 6.7
2015 6.5 7.9 7.0 6.2
2025 6.7 8.0 7.4 6.2
2035 7.1 7.6 8.1 6.2
18
Average end user cost projection in 2010 cents per kWh from several sources.
Via the Annual Energy Outlook 2012 Report, U.S. Energy Information Administration (2012)

19.  Minimum usage – minimum bill set on
60%
 Power factor – less than 0.87
 2011 – June 2012 average power factor =
85.8
19

20.  Enernoc emergency load response
program – run generators
 AEP energy efficiency/peak demand
reduction program – up to 50% rebate
20

21.  Uses of Aeration
 Mixing
 Biological Oxygen Needs
21

22. Mixing Control Biological Control
Average Conditions
Five Aeration Tanks 8200 cfm 7872 cfm
Influent and Effluent Channels 2306 cfm 2306 cfm
Reaeration Tank 705 cfm 705 cfm
Total 11211 cfm 10883 cfm
Mixing Control Biological Control
Average Conditions
Four Aeration Tanks 6500 cfm 7872 cfm
Influent and Effluent Channels 2306 cfm 2306 cfm
Reaeration Tank 705 cfm 705 cfm
Total 9511 cfm 10883 cfm
22

23.  Blowers – multistage centrifugal
 Two 400 HP 4160 volt - 10,000 cfm
 Two 350 HP 460 volt - 7,000 cfm
 Diffusers
 Aeration tanks EDI fine bubble diffusers
 Channels and reaeration tank coarse bubble
 Controls
 Blower inlet throttling
 DO monitoring
23

24. 24

25.  Types of diffusers
 Tank depth
 Surfactants
25

26. Electric
26

27. 27
PST 5-7 Total COD
Primary Effluent Total COD
DATE
11/1011/3
CONC.(mg/L)
400
300
200
100
PST 5-7 Total COD Mass rate
Primary Effluent COD Mass Loading
DATE
11/1011/3
50,000
40,000
30,000
20,000

28. 28
PST 5-7 Total CBOD
Primary Effluent Carbonaceous BOD
DATE
11/1011/3
CONC.(mg/L)
200
150
100
PST 5-7 Total CBOD
Primary Effluent CBOD Mass Loading
DATE
11/1011/3
20,000
10,000

29. 29
PST 5-7 TSS
PST 5-7 VSS
Primary Effluent Solids
DATE
11/1011/3
200
150
100
50
0
PST 5-7 TSS
PST 5-7 VSS
Primary Effluent Solids Mass Loading
DATE
11/1011/3
30,000
20,000
10,000
0

30. 30
PST 5-7 TKN
PST 5-7 Ammonia N
Primary Effluent Nitrogen
DATE
11/1011/3
40
30
20
10
0
PST 5-7 TKN
PST 5-7 Ammonia N
Primary Effluent Nitrogen Mass Loading
DATE
11/1011/3
4,000
3,000
2,000
1,000
0

31. 31
PST 5-7 Total P
Primary Effluent Total Phosphorus
DATE
11/1011/3
7
6
5
4
3
2
1
0
PST 5-7 Total P
Primary Effluent Total Phosphorus Mass Loading
DATE
11/1011/3
1,000
800
600
400
200
0

32. 32
AT Pass 1
AT Pass 2
AT Pass 3
Total
Aeration Tank 1-5 Variable Airflow
Maintain DO @ 2 mg/l
DATE
11/9/201211/7/201211/5/201211/3/201211/1/2012
15,000
14,000
13,000
12,000
11,000
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0

33. 33
AT Pass 1 DO
AT Pass 2 DO
AT Pass 3 DO
Aeration Tank Dissolved Oxygen
Manually Adjusted Airflow
DATE
11/10/201211/8/201211/6/201211/4/201211/2/2012
10
9
8
7
6
5
4
3
2
1
0

34. 34
AT Pass 1 DO
AT Pass 1 Airflow
Aeration Tank Dissolved Oxygen
Potential Surfactant Effect
DATE
11/10/201211/8/201211/6/201211/4/201211/2/2012
10
9
8
7
6
5
4
3
2
1
0
Airflowscfm
10,000
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
1,000
0

35.  Current cost of aeration ~ $13,000/month
 Denitrification
 High efficiency blowers
 Ultrafine bubble aeration
 Decouple aeration and mixing (install
separate mixing systems)
 Automated blower control
 Combination of options above.
35

36. 36
Total
26,027 MMBtu / year
$117,121 @
$4.50/MMBtu
Natural Gas
7,370 MMBtu / year
$33,165 / year
Digester Gas
16,457 MMBtu / year
$74,057 / year
Microturbine Heat Recovery
(Assume one running 24/7)
2,200 MMBtu /year
$9,900 / year
Microturbines
(Assume one running 24/7)
7,200 MMBtu / year
$32,400 / year used
Flare
2,246 MMBtu / year
$10,107 / year
Digester Heat
11,642 MMBtu / year
$52,389 / year
Building Heat
4,939 MMBtu /year
$26,670 / year

37. 37
0
200
400
600
800
1,000
1,200
1,400
1,600
1,800
1/1/2009 1/1/2010 1/1/2011 1/1/2012
Heat(MMBtu)
Natural Gas Purchased
$33,904 $24,560$27,230

38. 38
= $11.38/MMBtu
assuming 3% inflation

39. 39

40. 40

41. 41
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
1/1/2009 1/1/2010 1/1/2011 1/1/2012
Heat(Demanded/Required)(MMBtu)
Gas Lower Heating
Value
Heat Required by
Digesters
Note: Assumes 80% boiler efficiency.

42. 42
0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
110,000
120,000
130,000
140,000
150,000
160,000
170,000
1/1/2009 1/1/2010 1/1/2011 1/1/2012
GasProduced(Ft3/day)
Gas demand from one turbine
Gas demand from two turbines

43. 43
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
0
10
20
30
40
50
60
70
1/1/2009 1/1/2010 1/1/2011 1/1/2012
DigesterGas(ft3/day)
%Volatileoffeedsludge

44. 44
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
0
100
200
300
400
500
600
700
800
1/1/2009 1/1/2010 1/1/2011 1/1/2012
DigesterGas
VolatileAcids(mg/L)

45. 45
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
0
500
1,000
1,500
2,000
2,500
1/1/2009 1/1/2010 1/1/2011 1/1/2012
DigesterGas
Alkalinity

46. 46
%DigesterLoad(basedonlbsvs/ft3-day

47.  Septage and grease fed directly to the
digesters
 Bring in supplemental feedstock
 Digestion enhancement
47

48.  Benefits
 Increased gas production
 Reduce grease accumulation in primaries and other tanks
 Reduce biological load to aeration
 Challenges
 Requires plant modification to accept, store, and feed
grease to digester
 Digester upset, grease handling, and odor control are a
concern
 Requires cooperation of public
 Drawbacks
 Greater public access to the plant is likely
 More supervision may be required
48

49.  Benefits
 Increased gas production
 Reduced load to municipal landfills
 Possibly some income from disposal fees (doubtful)
 Community involvement in “green” project
 Challenges
 Requires community or business support
 Requires modifications to plant to bring in additional solids
 Could require upgrades to handle and use additional gas if done
on a large scale.
 Possible digester upset without careful control
 Drawbacks
 Increased solids management at plant
 Increased complexity and labor at plant
 Reduced gas production at landfill
49

50.  Benefits
 Increased gas production
 Increased solids destruction
 Achievement of class A biosolids possible with
some systems
 Challenges
 Limited change for improvement in gas production
if done alone
 Drawbacks
 Capital and operational cost must be weighed
against benefit
50

51.  By process
 General
 Baxter Street pumping
 Preliminary & primary treatment
 Secondary treatment
 Effluent pumps
 Solids processing & digestion
 Electrical upgrades
 Alternate energy
51

52.  By type
 Process modifications
 Energy generation
 Reduces energy consumption
 Additional ideas
52

53.  Today
 Review alternatives
 Brainstorming
 Initial screening
 Next
 J&H develop alternatives
53

54. 54

55. Rules: No bad ideas
No criticism of ideas
55
Brainstorming

56.  City selection  5 dots
 J&H selection
56

57. Channel Mixing
57

58.  Aerated channels require mixing to keep
solids suspended rather than a supply of
dissolved oxygen.
 Aeration tanks are deeper than channels.
Currently all air is pressurized to the same
pressure based on aeration tank depth,
which wastes energy.
58

59. 59

60. 60
Baxter Street
$36,728 Screening
$475
Grit Removal
$869
Aeration Tank Air
$113,598
Channel Air
$47,219 / year
29% of total aeration
Sludge Pumps
$37,875
Final Clarifiers
$2,085
Nitrification
$66,140
Disinfection
$688
Digestion,
42,779
Dewatering
$7,093
Stabilization
$463
Admin Building
$2,369
Miscellaneous
$87,492
Cost of Channel Aeration
($ / year)

61.  Separate blower and piping to operate channel
aeration at lower pressure.
 Mechanical channel mixing or “pulsed bubble mixing”
 Benefits
 Reduced energy bills (estimated $20,000 / year at current
energy prices)
 Nitrogen removal possible
 Simpler DO control and balancing (maybe?)
 Problems
 Capital expense ($220,000 -$300,000)
 Odor control
 Depleted DO in first portion of aeration tanks
61

62. 62

63. 63

64. 64

65. 65