Thermal Hydrolysis Process, or THP, offers an efficiency-boosting, sustainability-enhancing solution to utilities’ biosolids challenges. With THP of increasing interest to utilities across the U.S., this Black & Veatch presentation introduces THP and discusses its drivers, design considerations and integration challenges. Presented by Greg Knight, Black & Veatch’s U.S. THP Practice Leader, and Rick Lancaster, Regional Services Manager for United Utilities in the UK, the presentation uses the award-winning Davyhulme project as a case study. The material shows how THP can: • Generate savings by improving biosolids quality while reducing its quantity • Get more throughput to maximize use of existing assets • Reduce carbon footprint while increasing renewable power generation

1. MAY2015
RICK LANCASTER, UNITED UTILITIES
GREG KNIGHT, BLACK & VEATCH
A TURBOCHARGER FOR DIGESTION
THERMAL HYDROLYSIS AT DAVYHULME, UK

2. YOUR PRESENTERS
GREG KNIGHT
2
Greg Knight
BLACK & VEATCH
Senior Process Specialist & THP Practice Leader
Atlanta, GA
KnightGJ@bv.com
Tel. +1-770-521-8129
Rick Lancaster
UNITED UTILITIES
Regional Services Manager
Manchester, UK
Richard.Lancaster@uuplc.co.uk

3. AGENDA
GREG KNIGHT
3
1. Introduction to THP
2. Project Overview & Drivers
3. Integration Considerations
4. Commissioning
5. Operating Experience &
Optimization

4. ACKNOWLEDGEMENTS
GREG KNIGHT
4
Dave Belshaw: United Utilities Process Commissioning Engineer
Warren Bullough: Commissioning Manager, United Utilities
Rachel Edgington: Technical Lead, Sludge & Sustainability, United Utilities
John McNeil: Project Manager, United Utilities
John Thornton: Project Manager, Black & Veatch
Martin Jolly: Technical Director, Black & Veatch
Jack Tefler: Process Commissioning Engineer (Aqua Enviro) / Technical Officer (United Utilities)
Plus many others in the integrated delivery team for this project
• IChemE – International Award for Renewable Energy
Generation, 2013
• 27th British Construction Industry awards: Major Civil
Engineering Project of the Year, 2014
AWARDS

5. INTRODUCTION
TO THERMAL
HYDROLYSIS
GREG KNIGHT
5

6. WHAT DOES THERMAL HYDROLYSIS PROCESS
(THP) MEAN?
6
Complex Organics Simpler
Carbohydrates
• Thermal – using heat
• Lysis – breaking stuff apart
• Hydro – with water (solubilization)

7. CONFIGURATION
7
Cake to
land
Liquid
Sludge
Dewatering
CHPBoiler
Steam
Heat
Biogas
Digestion
Thermal
Hydrolysis
Dewatering
To IncineratorImported Cake

8. CAMBI THP
8
Heat(Steam)
PULPER REACTORS
(5 at Davyhulme)
FLASH TANK
SLUDGE FEED
(CONTINUOUS)
16% DS
320 oF
90 PSI
HOLD
FOR 30
MIN
DEPRESSURISE
TO 45 PSI
DEPRESSURISE
TO JUST ABOVE
ATMOSPHERIC
PRESSURE
SLUDGE
DISCHARGE
(CONTNUOUS)
225 oF
14% DS
RECIRCULATION

9. CAMBI MODELS
B2 B6 B12
• Single skid system
(pre-assembled)
• Up to 24 dtpd capacity
•Multiple skid system
(pre-assembled)
•Up to 90 dtpd capacity
• Shop assembled
components, on-site
installation
• Up to 135 dtpd
capacity
9

10. EXELYSTM (CONTINOUS SYSTEM)
SLUDGE FEED
(CONTINUOUS)
>22% DS
PRE HEAT
BOILER FEED
HEAT
RECOVERY
SLUDGE
140–220OFREACT @ 320 OF, 90 PSI
PLUG FLOW REACTOR
DILUTION WATER
10-12% DS
Steam
10
VEOLIA (KRUGER IN THE USA)
BIOTHELYSTM (BATCH SYSTEM)

11. Note also: slight increase in heating value of cake
(lower VS/TS but higher cake TS)
• Pathogen free product for
land application (Class A)
• Less digester volume (higher
loading rates)
• Higher COD and VS
conversion in digesters
• More biogas
• Less dry solids for disposal
• Better dewaterability (lower
VS)
• Less volume of wet sludge
for disposal
WHAT DOES THIS MEAN IN PRACTICAL
TERMS?
11

12. Key Cost Drivers in USA:
• Savings in disposal cost
• More sludge through existing digesters
PROJECT ECONOMICS – THP VS CONVENTIONAL
DIGESTION
12
FAVORABLE FOR THP
FAVORABLE FOR
CONVENTIONAL

13. 26th
Januar
y 2011
B&V
Description Units Existing New
Capacity of plant tds/a 39 000 121 000
Maximum energy
production
MW 3.7 11.5
Digester volume m3 60 000 60 000 (16 MG)
Feed to digester Dry solids (%) 5-6 11
Photo courtesy of
Cambi
Impact of THP at Davyhulme

14. PROJECT OVERVIEW
& DRIVERS
RICK LANCASTER
14

15. One of 10 Water and Sewerage Companies in
England and Wales
We provide water and treat wastewater for c.7
million people in the North West of England:
Ww is treated at over 500 wastewater treatment works
Sludge is treated in 20
digestion facilities
Treated sludge is
transported via 100Km
pipeline
7 large scale raw sludge
dewatering facilities
and over 500 Ww sites
25MW of installed
CHP
UNITED UTILITIES
15

16. Outlet:
We require 21,000 hectares per year to recycle our sludge to agriculture this
is equivalent to:
• 26,000 football pitches per year
The remaining sludge is incinerated with energy recovery at Shell Green
We produce, across the North West, approximately:
200,000 tonnes dry solids of sludge per year.
That is enough sludge to fill…
Old Trafford 10 times a year
Energy:
We treat sludge at 20 digestion sites generating approximately 33% of our total
Wastewater and Network energy needs every year, equivalent to 130 GWh.
This is sufficient to power over 50,000 homes every year
UNITED UTILITIES
16

17. From sludge to sea…
to a balance of recycling and disposal with
energy recovery
UNITED UTILITIES SLUDGE STRATEGY
17

18. Need 1 – to produce a product
suitable for agricultural land
application in the North West
Need 2 – higher quality
product and less volume to off-
set loss of land availability and
increased sludge production
60% loss due to..
Competition
Regulation
Need 3 – to maximise the
inherent value within sludge
reducing customer bills through
reduction in energy import
Need 4 – to reduce the carbon
footprint of our operations and
strategy
A STRATEGY FOR A CHANGING ENVIRONMENT
18

19. A NEW STRATEGY – THP AT DAVYHULME
A new strategy with a significant shift
towards advanced digestion over a
number of AMP’s
THP at
Davyhulme
3. To deliver an innovative
solution to minimise
investment
4. To provide a flexible outlet – production
of an enhanced treated product for
recycling and better utilisation of our
incineration facility
-5000
0
5000
10000
15000
20000
25000
30000
35000
40000
Existing Ad Digestion
AxisTitle
Axis Title
Chart Title
Contributory
Beneficial
Net Operating
2. To provided the lowest
operational carbon footprint
and option to deliver UU’s
strategy
1. To significantly increase
renewable energy
generation
80
90
100
110
120
130
140
FY09/10 FY10/11 FY11/12 FY12/13 FY13/14 FY14/15
GWh
19

20. DAVYHULME THP – THE PROJECT
4 x streams of THP
each 30 ttds/a –
allows shutdown to
be undertaken
without the need for
contingency
2 x sludge export
silo’s – 3 days
storage for
enhanced treated
sludge
5 x Combined Heat
and Power Engines –
12.4MW installed
capacity
2 x 9,000m3 gas bags
– the largest in
Europe
3 x sludge import silo’s
implemented to enable
optimisation of sludge
throughput – a sludge battery –
each tipper is worth c. £800
8 x 8,000m3 MAD
throughput has been
doubled
20

21. INTEGRATION
CONSIDERATIONS
GREG KNIGHT
21

22. 22
INTEGRATION CONSIDERATIONS

23. 23
PRE-DEWATERING

24. PRE-DEWATERING
24
CHP Jacket
Heat

25. 25
DIGESTER SYSTEMS – GAS TAKE
OFF AND MIXING

26. 26
DIGESTER MIXING
EXISTING MIXING
CONVENTIONAL SLUDGE
4% SOLIDS
EXISTING MIXING
TH DIGESTED SLUDGE
6% SOLIDS

27. 27
RECYCLE STREAMS

28. AMMONIA CONCENTRATION & LOAD
28
VS Destruction
DigesterFeedSolids
Concentration
Conventional
Digestion
1300 – 2000 mg/l
NH3-N
Digestion after
THP
2500 – 3200 mg/l
NH3-N
• Imported cake => significant increase in NH3 return
load
• Sodium hydroxide dosing upfront of tertiary BAFF plant

29. 29
CHP SYSTEMS

30. • Relocated 3 Jenbacher 2.4
MW engine generators
• 2 New Jenbacher 2.4MW
engine generators
• Total 12 MW installed
• 3 Combination steam
boilers, 18 ton per hour
steam output
• Boilers heated using
burned biogas + exhaust
waste heat from CHP
CHP ENGINES &
BOILERS

31. MANAGING STEAM DEMAND
31
Modelled – without optimization Modelled – with optimization
Actual – without optimization Actual – with optimization

32. COOLING OPTIONS
32
SLUDGE
IN 50oC
122 F
SLUDGE
OUT 40oC
104 F
PLANT
EFFLUENT IN
PLANT EFFLUENT
OUT
SLUDGE
IN 50oC
122 F
SLUDGE
OUT 40oC
104 F
WATER
Air
Make up
water +
chemicals
Blowdown
SLUDGE
IN 50oC
122 F
SLUDGE
OUT 40oC
104 F
GLYCOL/
WATER
POTALBLE
WATER

33. COMMISSIONING
33
GREG KNIGHT

34. • 7 lime stabilization facilities to convert & import to
Davyhulme – revocation of lime contracts
irreversible
• Commission digesters on TH sludge & ramp up
• Move 3 existing CHP engines
• Need to keep existing digesters heated until THP
comes on line
• Maximize electrical output during the
commissioning period (new & existing CHP)
• Ammonia load from dewatering at Davyhulme and
Shell Green
THE CHALLENGES
34

35. DYNAMIC MASS & ENERGY BALANCE
35
THP STREAM SLUDGE LOAD PLANT SLUDGE LOADS
EXPORT SLUDGE LOADS AMMONIA AT SHELL GREEN
ELECTRICAL OUTPUT / CHP AVAILABILITY DIGESTER HEAT AVAILABILITY

36. DIGESTER START UP
Digesters 1 & 2
cleaned out, new
gas mixing system
Digesters 3 to 8
not cleaned out,
change over
from mesophilic
digestion
36

37. PLANNING FOR DIGESTER START UP
37

38. 38
DIGESTER STABILITY MONITORING
Parameter pH
VFA/
Alkalinity
Ratio
Observation
of digester
foaming
Action
Status OK
Acceptable
limits >7.0 <0.3
No digester
foaming
observed.
No action required – continue with planned ramp up
regime.
Level 1 alert
Action limit <7.0 >0.3 First sign of
foaming
Begin dosing antifoaming agent if foaming observed.
No change in feed regime (monitor).
Level 2 alert
Action limit <6.8 >0.4
Significant
foaming
observed.
Stop increasing feed rate.
Remain at constant feed rate for 3 days.
Continue dosing antifoaming agent.
Level 3 alert – still out of limits after previous level 2 alert
Action limit <6.8 >0.4
Significant
foaming
observed.
Reduce feed rate by 20%. Remain at constant feed rate
for 3 days.
Continue dosing antifoaming agent.

39. STREAM 1 FULL SCALE RAMP UP
39Digester performance was very stable throughout
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
OrganicLoadingRate(kg.VS/m3
/d)
Days
Stream1 actual load (kgVS/m3/d) Stream1 planned ramp up (kgVS/m3/day)
Design organic loading rate
Planned hold over
Christmas period
Issues with pulper
feed dilution &
control
Full throughput
reached
Pulper feed
control improved

40. • Intended approach for Davyhulme
• Switch feed from non TH to TH sludge at low organic
loading
• Gradually ramp up TH feed over several weeks
STREAMS 2, 3 & 4 – CONVERTING
CONVENTIONAL DIGESTERS
40

41. STREAM 2 – RAMP UP
41
Sludge transferred
from digesters 1&2
Digester stability
issues

42. 42
DIGESTER STABILITY MONITORING

43. STREAM 4
Acclimatized sludge
transferred prior to
ramp up
Ramp up beat
schedule at ~25 days
43

44. RAMP UP SUMMARY
Stream Target Ramp
Up Period
(days)
Actual Ramp
Up Period
(days)
Volume of seed
biomass
(m3)
1 34 70 N/A
2 34 55 3000
3 34 34 2000
4 34 25 3000
Total 136 184
Original plan – 360 days

45. 45
Black & Veatch

46. OPTIMIZATION AND
OPERATING
EXPERIENCE
RICK LANCASTER
46

47. DAVYHULME THP - CHALLENGES
Uniquely complex system –
management of 60% of United Utilities
sludge
Steam management –
new operation for
United Utilities
specialist training
required
Shutdown for
annual statutory
inspection
Blend required to
pump sludge to
incinerator
System constraints – Nox limits at
Davyhulme and a need to Ammonia
balance the system
System wide
production
management –
taking account of
different lag times
and changes in
production
4747

48. DAVYHULME THP – A YEAR OF OPERATION
Parameter Units Target Measured
value
Thickening Polymer usage Kg/tds <10.0 5.96
Dewatering polymer usage kg/tds <10.0 8.07
Throughput tds/day 250.0 203*
Specific power consumption kWh/tds 197 152
Renewable energy
performance
KWh/tds 800 Up to 920
Cake dry solids % DS >28.5 31.3
Specific methane production Nm3/tds >257 259
Specific biogas production Nm3/tds 400 400
Sludge Product status Pass/Fail Enhanced Enhanced
Biogas utilisation to boilers % 8 4.1
Volatile solids destruction
rate
% 60 58 – 64**
CHP Biogas use % 91.2 94.3
Key performance parameters from a years
operation
We have seen good gas
production >400Nm3/tds
sludge treated
We have optimised gas
utilisation reducing the
gas used as fuel in the
boilers below 4% (target
8%) initially 12%
Energy generation per tds
treated sludge has
outperformed
expectations peaking at
920KWh/tds
Energy neutral – we are
approximately 96%
energy self sufficient at
times neutral. We also
power UU’s data centre
48

49. DAVYHULME THP – A FLEXIBLE OUTLET
Only incineration facility in
the World processing a
combination of advanced and
conventional sludge
We produce an
enhanced treated
standard cake suitable
for the NW land bank
– similar to class A
We currently export between
55,000 and 70,000 wet tonnes of
cake every year and require
>3,500Ha each year (1 in 3 return
rate).
Potential to export
120,000 wet tonnes of
sludge to agriculture
every year
Customer feedback:
‘First time I have ever had two
silage cuts and I have an increased
number of bales’
‘It looks like soil with no noticeable
odour’
We have generated a
new land bank in under
one year – 80% grass
land
49

50. Conclusion
Davyhulme
THP
£155m
Net Opex increase
Deliver an innovative solution
to minimise investment
£100m
Net Opex reduction
Produce an enhanced treated
product suitable for recycling in
the NW to implement UU’s
strategy
We have significantly reduced the sludge we need to
recycle due to the greater solids destruction through THP
and enhanced the quality to open up grass land – most of
all the customers love it!
Energy Neutrality for
Davyhulme
96%
Almost energy neutral 96% -Only utilising 74%
of capacity
Exceeding performance expectations - Full
utilisation at current performance = 80GWh/a
Reduce UU’s operational
carbon footprint and the
impact of the solution
6%
CONCLUSION
50

51. Questions
Greg Knight
BLACK & VEATCH
Senior Process Specialist & THP Practice Leader
Atlanta, GA
KnightGJ@bv.com
Tel. +1-770-521-8129
Rick Lancaster
UNITED UTILITIES
Regional Services Manager
Manchester, UK
Richard.Lancaster@uuplc.co.uk
51

52. www.bv.com