Advanced Sludge Treatment at Kensoha WWTP
Reducing Viscosity of Thickened Waste Activated Sludge, Improving Dewaterability of Digested Sludge, and Enhancing Biogas Production through Thermochemical Hydrolysis Process —— Kenosha Energy Optimized Resource Recovery Project Josh Gable and Zhongtian Li May 24th, 2017 CSWEA Annual Conference
Project Objectives
Kenosha Energy Optimized Resource Recovery Project
Objectives
Process
Improve efficiency of anaerobic digestion - Thickening centrifuges (THK Series) Improve digested sludge dewaterability
-PONDUS thermochemical hydrolysis
Realize energy self-sufficient for solids treatment
- Mesophilic anaerobic digester
Produce Class A biosolids
- Combined heat and power
-Klein Belt Dryer
Kenosha WWTP
Raw WW
Kenosha WWTP Wastewater Treatment
Lift Station
Grit Chamber
Primary Clarifier
Biological Treatment
Waste Activated Sludge
Primary Sludge
Anaerobic Digestion
Secondary Clarifier
Disinfection
Sludge Treatment
PONDUS TCHP
Dewatering
Cake
Klein Dryer
Lake Discharge
Class A Biosolids
Kenosha WWTP
Sludge Treatment at Kenosha WWTP
Process 1 2 3 4 5
Sludge Flow Primary Clarifiers Final Clarifiers Sludge Thickening, Thermo-Chemical Hydrolysis Anaerobic Digestion Solids Drying
Kenosha Project
Sludge Treatment Process at Kenosha WWTP
Proposed Retired ADs
Second Stage ADs
First Stage ADs
PONDUS TCHP Control Room
Centrifuges Combined Heat and Power Klein Sludge Dryer Class A Biosolids
Kenosha Project
PONDUS Thermo-Chemical Hydrolysis Process
TCHP Control Panel PONDUS Reactor
Kenosha Project Performance
Change of Sludge Morphology
Kenosha Project
Thickening and Dewatering Centrifuges
Primary Sludge Thickening Centrifuge
WAS Thickening Centrifuge
Digested Sludge Dewatering Centrifuge
Kenosha Project Performance
Centrisys Dewatering System
Flow rate: 50 – 70 GPM Polymer dosage: 23 – 27 lb/dry ton Cake Dryness: 28-29% Recovery: > 95%
Kenosha Project
Anaerobic Digestion
Digester Gas from Stage 1 Digestion
Digester Gas from Stage 2 Digestion
Gas Compression, Moisture and Siloxane Removals
Cleaned and Compressed Digester Gas Delivery
Kenosha Project
Combined Heat and Power
KRAFT Power Gas Engine
KRAFT Power Electric Generator
Cooling Equipment
Heat Supply from Cogen
Kenosha Project
Sludge Drying and Production of Class A Biosolids
Feed of Dewatered Sludge to Sludge Dryer
Dried Sludge Certified Class A Biosolids by Wisconsin Department of Natural Resources
Kenosha Project
Odor Control
Exhaust from CHP
Odorous Air Collection
Recirculation of Hot Air
Acid and Alkaline Scrubbers
Kenosha Project Performance
Performance
• Reduce sludge viscosity
• Change sludge floc morphology
• Improve digested sludge dewaterability
• Enhance biogas production
Kenosha Project Performance
Reduction of Sludge Viscosity TWAS
120,000
Apparent Viscosity (mPa.s)
TWAS 6.5% 22C LTWAS 5.8% 25.0C
100,000
> 80% Reduction 80,000
Hydrolyzed TWAS (LTWAS)
60,000
40,000
20,000
0 0
20
40 Stir RPM
60
80
Kenosha Project Performance
Reduction of Sludge Viscosity Change of Apparent Viscosity of LTWAS During 3-day Holding
25,000 LTWAS 6.0% 47.5C Holding Day 1 LTWAS 6.0% 38.2C holding Day 1 LTWAS 5.8% 25.0C Holding Day 1 LTWAS 5.8% 25.0C Holding Day 3
Apparent Viscosity (mPa.s)
20,000
15,000
10,000
5,000
0 0
10
20
30 40 Stir RPM
50
60
70
Kenosha Project Performance
Primary Sludge
4.5
90
4.0 85
3.5 Primary Sludge
3.0 80
2.5 2.0
75
1.5 1.0 0.5 0.0
70 TS %
VS % 65
Thickened WAS
Kenosha Project Performance
TWAS
8.0
76
7.0
75
6.0
74
5.0
73
4.0
72
3.0
71
2.0
70
1.0 0.0
TS %
VS %
69 68
Kenosha Project Performance
30
Dewatered AD Sludge Optimized Cake TS% with reliable cake piping
TS of Dewatered Sludge (%)
29 28 27 26 25 24 23
Project Start-up
Achieved Highest Reduced Cake TS% for TS% better sludge cake piping
from dewatering centrifuge to dryer
Installed lubrication system in cake pipe
22 2016
21
2017
20 Jan Feb Mar Apr May Jun
Monthly Average Values
Jul
Aug Sep Oct Nov Dec
Kenosha Project Performance
Improvement of Dewaterability
30% 29%
Cake Solids (% TS)
28%
Cake Dryness Improvement
27% 26%
Polymer Reduction
25% 24%
PONDUS Treatment
23%
Prior PONDUS Treatment
22% 20
25
30
35
Polymer Dosage (lb/dry ton)
40
45
Kenosha Project Performance
Dewatering Performance
33.0%
100.0%
Polymer: K275FLX Active Dosing: ~33 lb/dt
32.5%
99.5% 32.0% 99.0%
31.0% 98.5% 30.5% 30.0%
98.0%
29.5% 97.5%
Recovery 29.0%
Cake 97.0%
28.5% 40
50
60 Sludge Flow Rate (gpm)
70
80
Recovery
Total Solids
31.5%
Kenosha Project Performance
Thermally Dried Sludge
95.0 Dried Sludge TS（%）
94.5 94.0 93.5 93.0 92.5 92.0 91.5
2016
91.0
2017
90.5 90.0 Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
Kenosha Project Performance
Biogas Production
Biogas Production (cubic feet/lbs of VS Destroyed)
18 16 14 12 10 8 6 4 2 0
Kenosha Project Performance
Volatile Solids Reduction
80 Volatile Solids Reduction (%)
70 60 50 40 30 20 10 0
Occasions that the plant received aluminum sludge from drinking water plant
Kenosha Project Performance
Parameters Retention Time Operation Temperature Operation Pressure Biogas Production Enhancement Hydrolysis effect Electricity generation per ton of total dry solids feed
Performance Comparisons
Cambi THP* Approx. 30min
PONDUS TCHP 2 hours to 2.5 hours
Approx. 330 F
Approx. 150 F
6.4 atm (94 psi) Approx. 25% increased biogas dependent on sludge type Hydrolysis through flash decompression
1 atm (14.7 psi) Approx. 20% - 27% increased biogas dependent on sludge type Hydrolysis through moderate heating and sodium hydroxide dosing
980 (kWhr electricity/ton DS digested)
920 (kWhr electricity/ton DS digested)
Source: Bill Barber, Ph.D. WEF eShowcase – 19 October 2016
Summary
Dewaterability Improvement by PONDUS Thermo-Chemical Hydrolysis Process
• Implementation of thermochemical hydrolysis improved the dewaterability by 2.5% points with maximum cake dryness of 31%. • The thermal hydrolysis reactor effectively hydrolyzed TWAS with present total solids of 6-8.5%. At least 5-fold reduction of dynamic viscosity of TWAS by thermochemical hydrolysis. • No gel formation or regaining of viscosity was observed of the hydrolyzed TWAS treated by the TCHP. Sludge holding tested verified that the hydrolyzed TWAS by the TCHP was suitable for long-distance piping. • Biogas production was increased by 20% - 27% in the first year of project implementation. • Volatile solids destruction was increased from 60% to 64% in the first year of project implementation.
Thank you for your attention and interest!
CNP - Technology Water and Biosolids Corporation A division of Centrisys Corporation
9535 58th Place | Kenosha, WI 53144 USA P +1 (262) 764 3651 | F +1 (262) 764 8705 E [email protected]
Discovery more at CNP-Tec.com
A division of Centrisys Corporation
Project Objectives
Kenosha Energy Optimized Resource Recovery Project
Objectives
Process
Improve efficiency of anaerobic digestion - Thickening centrifuges (THK Series) Improve digested sludge dewaterability
-PONDUS thermochemical hydrolysis
Realize energy self-sufficient for solids treatment
- Mesophilic anaerobic digester
Produce Class A biosolids
- Combined heat and power
-Klein Belt Dryer
Kenosha WWTP
Raw WW
Kenosha WWTP Wastewater Treatment
Lift Station
Grit Chamber
Primary Clarifier
Biological Treatment
Waste Activated Sludge
Primary Sludge
Anaerobic Digestion
Secondary Clarifier
Disinfection
Sludge Treatment
PONDUS TCHP
Dewatering
Cake
Klein Dryer
Lake Discharge
Class A Biosolids
Kenosha WWTP
Sludge Treatment at Kenosha WWTP
Process 1 2 3 4 5
Sludge Flow Primary Clarifiers Final Clarifiers Sludge Thickening, Thermo-Chemical Hydrolysis Anaerobic Digestion Solids Drying
Kenosha Project
Sludge Treatment Process at Kenosha WWTP
Proposed Retired ADs
Second Stage ADs
First Stage ADs
PONDUS TCHP Control Room
Centrifuges Combined Heat and Power Klein Sludge Dryer Class A Biosolids
Kenosha Project
PONDUS Thermo-Chemical Hydrolysis Process
TCHP Control Panel PONDUS Reactor
Kenosha Project Performance
Change of Sludge Morphology
Kenosha Project
Thickening and Dewatering Centrifuges
Primary Sludge Thickening Centrifuge
WAS Thickening Centrifuge
Digested Sludge Dewatering Centrifuge
Kenosha Project Performance
Centrisys Dewatering System
Flow rate: 50 – 70 GPM Polymer dosage: 23 – 27 lb/dry ton Cake Dryness: 28-29% Recovery: > 95%
Kenosha Project
Anaerobic Digestion
Digester Gas from Stage 1 Digestion
Digester Gas from Stage 2 Digestion
Gas Compression, Moisture and Siloxane Removals
Cleaned and Compressed Digester Gas Delivery
Kenosha Project
Combined Heat and Power
KRAFT Power Gas Engine
KRAFT Power Electric Generator
Cooling Equipment
Heat Supply from Cogen
Kenosha Project
Sludge Drying and Production of Class A Biosolids
Feed of Dewatered Sludge to Sludge Dryer
Dried Sludge Certified Class A Biosolids by Wisconsin Department of Natural Resources
Kenosha Project
Odor Control
Exhaust from CHP
Odorous Air Collection
Recirculation of Hot Air
Acid and Alkaline Scrubbers
Kenosha Project Performance
Performance
• Reduce sludge viscosity
• Change sludge floc morphology
• Improve digested sludge dewaterability
• Enhance biogas production
Kenosha Project Performance
Reduction of Sludge Viscosity TWAS
120,000
Apparent Viscosity (mPa.s)
TWAS 6.5% 22C LTWAS 5.8% 25.0C
100,000
> 80% Reduction 80,000
Hydrolyzed TWAS (LTWAS)
60,000
40,000
20,000
0 0
20
40 Stir RPM
60
80
Kenosha Project Performance
Reduction of Sludge Viscosity Change of Apparent Viscosity of LTWAS During 3-day Holding
25,000 LTWAS 6.0% 47.5C Holding Day 1 LTWAS 6.0% 38.2C holding Day 1 LTWAS 5.8% 25.0C Holding Day 1 LTWAS 5.8% 25.0C Holding Day 3
Apparent Viscosity (mPa.s)
20,000
15,000
10,000
5,000
0 0
10
20
30 40 Stir RPM
50
60
70
Kenosha Project Performance
Primary Sludge
4.5
90
4.0 85
3.5 Primary Sludge
3.0 80
2.5 2.0
75
1.5 1.0 0.5 0.0
70 TS %
VS % 65
Thickened WAS
Kenosha Project Performance
TWAS
8.0
76
7.0
75
6.0
74
5.0
73
4.0
72
3.0
71
2.0
70
1.0 0.0
TS %
VS %
69 68
Kenosha Project Performance
30
Dewatered AD Sludge Optimized Cake TS% with reliable cake piping
TS of Dewatered Sludge (%)
29 28 27 26 25 24 23
Project Start-up
Achieved Highest Reduced Cake TS% for TS% better sludge cake piping
from dewatering centrifuge to dryer
Installed lubrication system in cake pipe
22 2016
21
2017
20 Jan Feb Mar Apr May Jun
Monthly Average Values
Jul
Aug Sep Oct Nov Dec
Kenosha Project Performance
Improvement of Dewaterability
30% 29%
Cake Solids (% TS)
28%
Cake Dryness Improvement
27% 26%
Polymer Reduction
25% 24%
PONDUS Treatment
23%
Prior PONDUS Treatment
22% 20
25
30
35
Polymer Dosage (lb/dry ton)
40
45
Kenosha Project Performance
Dewatering Performance
33.0%
100.0%
Polymer: K275FLX Active Dosing: ~33 lb/dt
32.5%
99.5% 32.0% 99.0%
31.0% 98.5% 30.5% 30.0%
98.0%
29.5% 97.5%
Recovery 29.0%
Cake 97.0%
28.5% 40
50
60 Sludge Flow Rate (gpm)
70
80
Recovery
Total Solids
31.5%
Kenosha Project Performance
Thermally Dried Sludge
95.0 Dried Sludge TS（%）
94.5 94.0 93.5 93.0 92.5 92.0 91.5
2016
91.0
2017
90.5 90.0 Jan Feb Mar Apr May Jun
Jul
Aug Sep Oct Nov Dec
Kenosha Project Performance
Biogas Production
Biogas Production (cubic feet/lbs of VS Destroyed)
18 16 14 12 10 8 6 4 2 0
Kenosha Project Performance
Volatile Solids Reduction
80 Volatile Solids Reduction (%)
70 60 50 40 30 20 10 0
Occasions that the plant received aluminum sludge from drinking water plant
Kenosha Project Performance
Parameters Retention Time Operation Temperature Operation Pressure Biogas Production Enhancement Hydrolysis effect Electricity generation per ton of total dry solids feed
Performance Comparisons
Cambi THP* Approx. 30min
PONDUS TCHP 2 hours to 2.5 hours
Approx. 330 F
Approx. 150 F
6.4 atm (94 psi) Approx. 25% increased biogas dependent on sludge type Hydrolysis through flash decompression
1 atm (14.7 psi) Approx. 20% - 27% increased biogas dependent on sludge type Hydrolysis through moderate heating and sodium hydroxide dosing
980 (kWhr electricity/ton DS digested)
920 (kWhr electricity/ton DS digested)
Source: Bill Barber, Ph.D. WEF eShowcase – 19 October 2016
Summary
Dewaterability Improvement by PONDUS Thermo-Chemical Hydrolysis Process
• Implementation of thermochemical hydrolysis improved the dewaterability by 2.5% points with maximum cake dryness of 31%. • The thermal hydrolysis reactor effectively hydrolyzed TWAS with present total solids of 6-8.5%. At least 5-fold reduction of dynamic viscosity of TWAS by thermochemical hydrolysis. • No gel formation or regaining of viscosity was observed of the hydrolyzed TWAS treated by the TCHP. Sludge holding tested verified that the hydrolyzed TWAS by the TCHP was suitable for long-distance piping. • Biogas production was increased by 20% - 27% in the first year of project implementation. • Volatile solids destruction was increased from 60% to 64% in the first year of project implementation.
Thank you for your attention and interest!
CNP - Technology Water and Biosolids Corporation A division of Centrisys Corporation
9535 58th Place | Kenosha, WI 53144 USA P +1 (262) 764 3651 | F +1 (262) 764 8705 E [email protected]
Discovery more at CNP-Tec.com
A division of Centrisys Corporation
