Lean Six Sigma Increasing Waste Activated Sludge Cheryl Cronin, Waste Water Treatment Plant.
Transcript of Lean Six Sigma Increasing Waste Activated Sludge Cheryl Cronin, Waste Water Treatment Plant.
Lean Six Sigma
Increasing Waste Activated SludgeCheryl Cronin, Waste Water Treatment Plant
Project Description
Objective: Increase gallons of W.A.S. processed by 40% and increase Total Solids to 4 to 5%
Problem Problem Statement:Statement:
• Only 50% of W.A.S is processed through the Centrifuge currently at an average Total Solids of 2.2%.
• Gallons wasted in 1999 – 176.15 MG• Gallons Processed at Centrifuge – 88.1 MG• Average TS (Thickened) – 2.2%• Average TS (W.A.S) – 0.7%
Benefits
•Savings of $28,000 per year (fuel and treatment)
•$1.7 M for additional digester space
•Plant able to treat 88,000,000 more gallons per year – Reduction in CSO’s
Champion: Ted Rhinehart
Financial: Ned Byrer
Black Belt: Cheryl Cronin
Mechanic: Brian Panzer
Process Analyst: Gwen Bard
Laboratory: John Kohne
Operator: Mike Glymph
Operator: Jeff Vachon
Technical: Chris Gach
Project Team
• Measurement: 07/17/00
• Analyze: 08/25/00
• Improvement: 09/29/00
• Control: 11/03/00
• Completion 12/30/00
Schedule
• Digester Space – Less Water, less energy for heating.• 33% reduction in use = $10,000.00
• Additional Digesters• “Class A” sludge must have a 38% reduction in Volatile
Solids and 15 day Detention time. • Currently there is an average 45% reduction and 7 day
detention. By EPA standards, another digester is needed to achieve a 15 day detention at a cost of $1.7M.
• Reduction of Million Gallons Treated • $18,000 in savings
• Increased Capacity of Primaries Tanks
Savings
“Y”
Million gallons of W.A.S. processed through Centrifuge at 4% TS or higher per week
Y =
Clarifiers with Sludge
WAS Wet Well
CentrifugeThickened Sludge Pumping
Thickened Sludge Pumping
50,000 Foot Process Map
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Process Step Process Inputs Waste
Tim
e
Wasting R
ate
Thic
k S
ludge
Thin
Slu
dge
Centr
ate
Ideal S
ludge
Plu
gged
Lin
e
Total
1 Clarifier Blanket Level 9 9 0 0 1 1 1 1172 Clarifier MLSS 9 9 0 0 1 1 1 1173 Clarifier SSV 9 9 0 0 1 1 1 117
Clarifier Operator Time 9 1 0 0 1 1 1 85
4 Wet WellWet Well Height
9 9 0 0 1 1 1 117
Wet Well Operator Time 9 1 0 0 1 1 1 855 Centrifuge Pinion Speed 1 1 0 0 5 9 1 1056 Centrifuge Load 1 1 0 0 1 9 1 1017 Centrifuge Feed Rate 5 5 0 0 1 5 1 109
Centrifuge Operator Time 1 1 0 0 1 9 1 101
8 CentrifugeTSS incoming sludge
1 1 0 0 1 5 1 65
9 Thickened PumpThick Sludge 1 1 0 0 1 1 9 9310Thickened PumpPSI 1 1 0 0 1 1 9 93
Thickened PumpOperator Time 1 1 0 0 1 1 9 93Thickened PumpON 1 1 0 0 1 9 9 165Thickened PumpOFF 1 1 0 0 1 1 1 29
11Thickened PumpWet Well Height
1 1 0 0 1 1 1 29
12 Overall Operator Time 5 1 0 0 1 9 5 161
13 OverallSeason Weather
5 1 0 0 1 1 1 57
14 015 016 017 018 019 020 0
0
Total 399
196
0 0 17
405
0 0 264
0 0 0 0 0 0
C & E Matrix
0Subgroup 10 20 30
4
5
6
7
8
Indi
vid
ual V
alue
66 6 2
1
1
6
Mean=5.83
UCL=7.426
LCL=4.234
0
1
2
Mov
ing
Ran
ge
R=0.6
UCL=1.960
LCL=0
Thickened Sludge Solids for September 2000
% Solids in September
• After completing process mapping and the C & E matrix we were able to improve the process by moving the average thickness of the sludge to 5.2% and have kept the centrifuge running for 3months non-stop.
• My new objective is to increase the gallons of WAS sludge processed by 40% and increase the thickness of the sludge to 6 to 8%.
Revised Objective
0 50 100
0
5
10
15Individual and MR Chart
Obser.
Indi
vidu
al V
alue
Mean=4.23
UCL=8.265
LCL=0.1953
0.0
2.5
5.0
7.5
Mov
.Ran
ge
R=1.517
UCL=4.957
LCL=0
105 115 125
Last 25 Observations
1.0
2.5
4.0
5.5
Observation Number
Val
ues
4 8Ppk: 0.02Pp: 0.41Scale: 4.76037Shape: 2.52216
Overall (LT)
Capability PlotProcess Tolerance
Specifications
I I I
I I I
1 10
Weibull Prob Plot
0 5 10
Capability Histogram
Thickened Sludge Solids
14121086420
USLLSL
Capibility Thickened Sludge
PPM Total
PPM > USL
PPM < LSL
PPM Total
PPM > USL
PPM < LSL
PPM Total
PPM > USL
PPM < LSL
Ppk
PPL
PPU
Pp
Cpm
Cpk
CPL
CPU
Cp
StDev (Overall)
StDev (Within)
Sample N
Mean
LSL
Target
USL
603087.35
155464.16
447623.19
526176.59
94071.62
432104.97
561403.51
78947.37
482456.14
0.04
0.04
0.34
0.19
*
0.06
0.06
0.44
0.25
1.74681
1.34489
114
4.23
4.00
*
6.00
Exp. "Overall" PerformanceExp. "Within" PerformanceObserved PerformanceOverall Capability
Potential (Within) Capability
Process Data
Within
Overall
Capability
• Developed a more timely method to measure the influent W.A.S
• Developed a method to measure the thickened sludge out of the centrifuge during production
• Current methods are 24 hours behind actual operation
Measurement Studies
• Rented a viscometer and did an initial study that told us that we should be able to correlate CPs with % solids.
• Did a Gage R % R to confirm
Thickened Sludge Measurement System
Gage name:Date of study:Reported by:Tolerance:Misc:
thickened sludge9-21-00Cheryl Cronin.4%
%Contribution %Study Var %Tolerance
Gage R&R Repeat Reprod Part-to-Part
0
5000000
10000000
15000000
Components of Variation
Per
cent
Gage R&R (ANOVA) for C2
Gage R & R Study on Effluent Measure System
StdDev Study Var %Study Var %ToleranceSource (SD) (5.15*SD) (%SV) (SV/Toler) Total Gage R&R 1622.6 8356.3 13.90 8.36E+05 Repeatability 1037.6 5343.4 8.89 5.34E+05 Reproducibility 1247.5 6424.5 10.68 6.42E+05 C1 75.6 389.2 0.65 38923.91 C1*trials 1245.2 6412.7 10.66 6.41E+05 Part-To-Part 11563.4 59551.5 99.03 5.96E+06
Total Variation 11676.7 60134.9 100.00 6.01E+06
Number of Distinct Categories = 10
Effluent Gage Stats
Gage name:Date of study:
Reported by:Tolerance:
Misc:
Influent10-18-00
Chery l Cronin1000 ppm
0
0.35
0.45
0.55
0.65
0.75
0.85
0.95
1.05 Bob J eff M ik e
Xbar Chart by Operator
Sam
ple
Mean
Mean=0.6983UCL=0.7512
LCL=0.6455
0
0.00
0.05
0.10
0.15 Bob J eff M ik e
R Chart by Operator
Sam
ple
Range
R=0.05167
UCL=0.1330
LCL=0
1 2 3 4 5 6 7 8 9 10
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Trial
OperatorOperator*Trial Interaction
Avera
ge
Bob
Jeff
Mike
Bob Jeff Mike
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Operator
By Operator
1 2 3 4 5 6 7 8 9 10
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Trial
By Trial
%Contribution
%Study Var
Gage R&R Repeat Reprod Part-to-Part
0
50
100
Components of Variation
Perc
ent
Influent Gage
Gage R & R Study on Influent Measure System
StdDev Study Var %Study VarSource (SD) (5.15*SD) (%SV) Total Gage R&R 0.040044 0.20623 19.76 Repeatability 0.035285 0.18172 17.42 Reproducibility 0.018934 0.09751 9.35 Operator 0.018934 0.09751 9.35 Part-To-Part 0.198604 1.02281 98.03 Total Variation 0.202601 1.04339 100.00
Number of Distinct Categories = 7
Influent Gage Stats
• Collected Data on Operators, Shift, Wet Well Height, Lab centrifuge results, Feed rate, Pinion Speed, Load, Viscometer results.
• Length of the Test 12 days
• Purpose to eliminate more “Xs”
Multi-Vari Testing
-2 0 2 4 6 8 10 12 14
LSL USL
Process Capabil ity Analysis for lab % sol
USL
Target
LSL
Mean
Sample N
StDev (Within)
StDev (Overall)
Cp
CPU
CPL
Cpk
Cpm
Pp
PPU
PPL
Ppk
PPM < LSL
PPM > USL
PPM Total
PPM < LSL
PPM > USL
PPM Total
PPM < LSL
PPM > USL
PPM Total
8.00000
*
4.00000
5.85978
138
1.34137
2.52848
0.50
0.53
0.46
0.46
*
0.26
0.28
0.25
0.25
376811.59
376811.59
753623.19
82800.25
55295.15
138095.39
231007.21
198652.47
429659.68
Process Data
Potential (Within) Capability
Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance
Within
Overall
Multi-Vari Study
• We can make either thick or thin sludge but have problems making sludge in the 6 to 7 % range.
• We see that operators still have separate methods for making sludge.
• We have developed a reliable method for determining the thickness of influent sludge.
• Load is significant to making thick sludge
Conclusions to Multi-Vari
• Wet well height is not significant
• Operators have a big impact on sludge produced
Conclusions to Multi-Vari
Centrifuge runs 44.9% of the available time
Progress Update
INITIAL CAPABILITY
POST-PROJECT CAPABILITY
Centrifuge runs 82% of available time
Our goal was to improve processing time by 40 %. To date processing time has improved 37.3%
Total Improvement
Centrifuge Run time vs Actual Hrs in months
0
100
200
300
400
500
600
700
800
July Aug. Sept. Oct. Nov. Dec.
200
Ho
urs
Actual Hrs. Ran Actual Hours in Month
Total Hours for last 6 months of 2000. = 4416
Total Centrifuge run time = 3631or 82.2% of total time.
Centrifuge Runtime
July-December 2000
2.2% Average Total Solids
Progress Update
Initial Capability
Final Capability
5.01% Average Total Solids
Initial Goal
Increase to 4-5% Average Total Solids
Sludge Thickness
02468
Month
Pe
rce
nt
Monthly Average
Goal
3.4% 4.7% 5.1% 5.8% 5.6% 5.3% 5.0%
Thickening Results
• Volatile Solids Reduction in 1999 was 44.9% and in the last 6 months of 2000 it has increased to 58.4% Goal is to be above 38%
• Detention time in the Digesters in 1999 was 7.3 days and since this project was started the average detention time has increased to 10 days in December . Goal is to be 15days or better.
Progress Update
Digester Sludge 1999 thru 2000
0
2
4
6
8
10
12
14
Jan.
Feb.
Mar
.
April
May
June
July
Aug.
Sept
.
Oct.
Nov
.
Dec
.
Jan.
Feb.
Mar
.
April
May
June
July
Aug.
Sept
.
Oct.
Nov
.
Dec
.
2 years
M.G
. Digested Sludge
Linear (Digested Sludge)
Sludge Flow to Digester 1999-2000
• In 1999 $8,200 was spent on diesel fuel.
• In 2000 $244. was spent on diesel fuel.
Progress Update
MeasureMeasure
AnalyzeAnalyze
ImproveImprove
ControlControl
ProjectDescription
ProcessMap
C & EMatrix
PreliminaryFMEA MSA
InitialCapability Study
Multi-Vari
DOE (or other improvement)
ControlPlan
Hand OffTraining
Final Capability
Study
OwnerSign-Off
Final ProjectReport
Project TrackingProject Tracking
• Set up at DOE (February)
• Develop a control Plan (March)
Next Step
In December of 2006, all equipment and programming changes were completed. The operators no longer have to make any adjustments once the process has started. They only have to set the load needed and the PLC does the rest.
Hands-Off Training