Corporation of the Town of Perth Drinking Water System 2020 Summary Report
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Corporation of the Town of Perth
Drinking Water System
2020 Summary ReportTable of Contents
DWS Summary Report Overview ..................................................................................... 4
DWS Information.............................................................................................................. 5
SECTION 1 – FAILURE TO MEET REQUIREMENTS ................................................... 6
1.1. Adverse Water Quality Incident reports (Drinking Water System) .......................... 6
1.1.1 AWQI # 151597 (WTP operational issue) ................................................ 6
1.2. Ministry Orders ....................................................................................................... 6
1.2.1. Drinking Water System ............................................................................ 6
1.2.2. Water Treatment Subsystem ................................................................... 6
1.3. Notifications to MECP (MOECC) regarding operational issues .............................. 6
1.3.1. WTP treatment operation continuing without proper coagulant addition. . 6
1.4. MOECC Identified Known Failures to Meet Requirements ..................................... 7
1.4.1. Drinking Water System ............................................................................ 7
1.5. MOECC identified areas for possible improvement ................................................ 8
1.5.1. Drinking Water System ............................................................................ 8
1.5.2. Water Treatment Subsystem ................................................................... 8
1.6. Additional concerns meeting potential compliance or operational requirements .... 9
1.6.1. Drinking Water System .......................................................................... 10
1.6.2. Water Treatment Subsystem ................................................................. 10
1.6.3. Water Distribution Subsystem ................................................................ 11
SECTION 2 – SUMMARY OF PLANT FLOWS ............................................................ 12
2.1. Raw Water (Source water) ................................................................................... 12
2.2.1. Average Daily Service Water Flow: ........................................................ 14
2.2.2. Service Water Discharge: ...................................................................... 14
2.3. Plant process water .............................................................................................. 14
2.3.1. Waste Volumes ...................................................................................... 15
2.3.2. Geo tube membrane bag use ................................................................ 16
SECTION 3 – SUMMARY OF DRINKING WATER SYSTEM ABILITIES .................... 17
3.1. Water Treatment Ability ........................................................................................ 17
3.1.1. Disinfection ability .................................................................................. 173.1.2. Chlorine Dioxide use .............................................................................. 17
3.1.3. Coagulation abilities ............................................................................... 18
3.1.4. Flocculation and sedimentation abilities ................................................. 19
3.1.5. pH adjustment (use of lime) ................................................................... 19
3.1.6. Fluoridation abilities ............................................................................... 20
3.1.7. Pumping capacity................................................................................... 20
3.1.8. Process Wastewater Residue Management ability ................................ 22
3.1.9. Computer System .................................................................................. 23
3.2. Water Taking Ability.............................................................................................. 23
3.3. Water Storage Ability ............................................................................................ 23
3.4. Water Treatment and Distribution Personnel ........................................................ 25
Appendix ...................................................................................................................... 26
4.1 Appendix Table 1 – Summary of Flows January 1, 2020 to December 31, 2020 . 26
4.2 Appendix Table 2 – Historical Average Daily Treated Water Flow (m³) ................ 27
4.3 Appendix Table 3 - 2020 Raw Water Taking ........................................................ 28
4.4 Appendix: MOECC 2020 Inspection Report Non-compliance issues and
Recommendations ......................................................................................................... 292020 DWS Summary Report
DWS Summary Report Overview
A Summary Report, as per Ontario Regulation 170/03, Schedule 22 must be prepared for
each drinking water system in the province of Ontario. The report must be provided no
later than March 31 to members of Municipal Council.
The DWS Summary report will cover a period for the preceding calendar year, January 01
to December 31, 2020.
The completion and presentation of this report will also fulfill the requirement for a
compliance report to be produced in accordance applicable regulations.
Section 1 contains,
any failures during the reporting periods to achieve the requirements of the Safe
Drinking Water Act, associated drinking water regulations and guidelines, any
approvals, any operating licences or permits, or any orders applicable to the Perth
DWS system;
duration of the failure, and measures taken to correct the failure;
any priority concerns that might lead to failures to meet the operating requirements.
Section 2 contains,
summary of quantities and flow rates of water taken from the Tay River, in addition to
water production and process wastewater generation.
Section 3 contains,
an overview summary of the DWS water treatment abilities
summary of the DWS water taking ability, DWS water storage ability,
summary of DWS operating personnel
Supplemental Perth DWS information sources would include, but not limited to,
The Town of Perth Water Treatment Plant year end documentation,
The Town of Perth Water Distribution year end documentation,
The Town of Perth DWS Annual Report.
Supplemental government legislation sources would include, but limited to,
Safe Drinking Water Act, 2002
Ontario Regulation 170/03, Drinking Water Systems
Ontario Regulation 169/03, Ontario Drinking Water Quality Standards
Ontario Regulation 128/04, Certification of Drinking Water System Operators and Water
Quality Analysts
It is noted to ensure currency, up to date documents can be reviewed at http://www.e-laws.gov.on.ca.
Supplemental government support documentation is available at the Ministry of the Environment
and Climate Change’s Drinking Water Ontario website, https://www.ontario.ca/page/drinking-water.
Perth Drinking Water System Summary Report 2020 Page 4DWS Information
Drinking-Water System Number 220001272
Drinking-Water System Name: Perth Drinking Water System
Drinking-Water System Owner: Perth, The Corporation of the Town of
Period being reported: Jan 01, 2020 to Dec 31, 2020
Latest MOECC Inspection Nov 10, 2020 (site visit); Jan 2021 (document review)
Previous MOECC Inspection Nov 20, 2019
Drinking-Water System Category: Large Municipal Residential System (LMRS)
Class III Water Treatment Subsystem,
Drinking Water System Facilities
Class I Water Distribution Subsystem
Municipal Drinking Water Licence (MDWL) 160-101
Licence Issue Date August 04, 2016
Licence Revision Date (most recent) August 02, 2017 (Schedule A revision)
Licence Expiry Date August 03, 2021
Drinking Water Works Permit 160-201
DWWP Issue Date August 04, 2016
DWWP Expiry Date August 03, 2021
Permits to Take Water 7770-A8HKRH
PTTW Issue Date March 29, 2016
PTTW Expiry Date March 31, 2026
Water Taking Location Tay River
Financial Plan Number (under O. Reg. 453/07) 160-301
Accredited Operating Authority The Corporation of the Town of Perth
Operating Authority No. 160-OA1
Operational Plan No. 160-401
Perth Drinking Water System Summary Report 2020 Page 5SECTION 1 – FAILURE TO MEET REQUIREMENTS
1.1. Adverse Water Quality Incident reports (Drinking Water System)
1.1.1 AWQI # 151597 (WTP operational issue)
A loss of proper coagulation in the treatment briefly occurred August 23, 2020, during
power outages and SCADA operational issues. It was reported to SAC as an operational
report filed under O.Reg 170 sec 16.4. The incident however was filed as an AWQI
report, despite no adverse tests and adverse effects to WTP operations. (see 1.3.1)
1.2. Ministry Orders
1.2.1. Drinking Water System
No MOE orders issued.
1.2.2. Water Treatment Subsystem
No MOE orders issued.
1.2.3. Water Distribution Subsystem
No MOE orders issued.
1.3. Notifications to MECP (MOECC) regarding operational issues
1.3.1. WTP treatment operation continuing without proper coagulant addition.
On August 23, 2020, a coagulant pump faulted out during power flickering (brief outages)
affecting SCADA PLC and equipment malfunctions. The off-site on-call operator was able
to shut down LLP operations, with only 4 approximate minutes of poor coagulation that
occurred. A follow up immediate on-site visit indicated more than sufficient floc present in
treatment tank, and no implications or adverse effect to WTP operations.
As part of WTP procedure, SAC was notified as a precautionary measure under O.Reg
170 sec 16-4 (an observation made that might impact the disinfection ability of the
treatment process), and considering a recent ES SOP release regarding loss of
coagulation operations. It was felt there was no anticipated impact to the disinfection
ability of the water treatment process due to the brief times involved.
In contacting MECP Spills Action Center (SAC), it was filed as an AWQI report, whereas it
was felt it was only an operational concern reporting.
Perth Drinking Water System Summary Report 2020 Page 61.4. MOECC Identified Known Failures to Meet Requirements
An MECP DWS inspection was conducted Nov 20, 2019, with the Inspector’s report
released March 30, 2020. Required action items are listed below in sections 1.4.1 to
1.4.3.
1.4.1. Drinking Water System
Requirement failure Requirement location Duration of failure Any corrective action taken
Operations and Prior to Phase II Residue OM manuals or Staff had created their own
Maintenance manuals Management (BET) required operational procedures manuals from
did not meet coming into operation, flow and PI supplier training sessions prior
requirements proper documentation diagrams were not to start up.
and drawing were not supplied by
incorporated into OM Contractors prior to Contractors supplied OM
manuals turnover of project. documentation well over 1
year after operations start up.
ES staff created updated BET
process flow drawings (not
supplied by contractors).
ES SOP created regarding
having proper OM manual(s)
documentation prior to project
start up.
Proper reporting (AWQI#144718) Feb Newer employees Town ES staff made aware of
procedures for 2019 WD lab result was not fully aware of proper MECP adverse water
adverse water quality not immediately verbal proper AWQI reporting procedures and
not followed notified, and done so reporting forms.
after conversation with procedures.
MECP ES SOP (and QMS docs)
reviewed and updated.
1.4.2. Water Treatment Subsystem
Requirement failure Requirement location Duration of failure Any corrective action taken
1.4.3. Water Distribution Subsystem
Requirement failure Requirement location Duration of failure Any corrective action taken
Perth Drinking Water System Summary Report 2020 Page 71.5. MOECC identified areas for possible improvement
An MECP DWS inspection was conducted Nov 20, 2019, with the Inspector’s report
released March 30, 2020. The Report contained some recommendations and best
practice issues identified during the inspection period, to which owners and operators can
develop an awareness of and consider measures to address them, all in the interest of
continuous improvement.
1.5.1. Drinking Water System
Any corrective
Issue noted Recommendation Status
action taken
No harmful algal The Town develop and implement a HAB Plan options Will likely become a
bloom (HAB) monitoring plan being requirement with
monitoring plan in developed. new MDWL (2021),
place and specific needs
outlined
1.5.2. Water Treatment Subsystem
Any corrective
Issue noted Recommendation Status
action taken
SCADA cyber That the Town ensure that there are Issue has been Continual efforts to
security cyber security provisions related to a high priority improve whenever
operation of the drinking water system. with WTP staff possible during IT
throughout work and upgrades.
SCADA
development
WTP backup power That a permanent generator installation New 350 kW New generator
generation occurs with proper underground wiring stationary upgrade from 200
and access ports, one that is sized for generator kW portable unit
current WTP needs. installed Oct
2020
Dechlorination duplex That the Town is required to ensure that Unit currently In effort to provide
pump panel not being the dechlorination duplex pump panel is not usable as dechlorination of
used operational in accordance with Schedule designed due backwash water,
C of DWWP #160-201. to location, WTP staff created
electrical install an interim system
issues, and (manual ops), and
automatic ops continue to use
issues until design flaws
are addressed.
Dechlorination That the Town is required to ensure that Not installed WTP staff do grab
chlorine analyzer not the chlorine residual analyzer for the during initial sampling during
installed dechlorination system is installed build, and water discharging
location/type to river, as per
issues to MDWL 4.4 (Table 7)
overcome
Perth Drinking Water System Summary Report 2020 Page 8Use SCADA data That the WTP Operators consider using Mentioned in On-going measures
more to record min’s the data from the SCADA Daily Reports to past reports, done to include
and max’s for better provide the information required by as a method of SCADA report data
assess compliance, Section 12(1) of O. Reg. 170/03; and that improving data into monthly reports
and reflect multiple WTP operators review the SCADA interpretation and use as an
low/high events auditing tool when
Monthly Reports on a regular basis.
review of data
Single phone line for That the Town maintain a dedicated Mentioned in In 2019/20, SCADA
multiple alarm phone line to support the WIN911 past reports. comm lines system
notification systems communication system; that a separate was upgraded, and
backup system for the autodialer system improvements
is provided, and that the autodialer is continue to be
connected to a dedicated phone line to implemented
ensure a fully functioning and secure off-
site alarm notification system.
A fixed pH value of That the Town proceed with connecting Mentioned in TW pH is being
7.5 is used in the CT the online continuous pH meter to the past reports. monitored by
calculations SCADA system for the treated water to SCADA, and using
allow the actual (real-time) pH values to The use of 7.5 as part of CT
be used in the SCADA CT calculations. pH reflects the calculations is
higher limit of being considered.
typical ranges
1.5.3. Water Distribution Subsystem
Any corrective
Issue noted Recommendation Status
action taken
WD free chlorine That the WDS operators record the actual To implement Will consider
results listed as >2, or chlorine residual reading to two decimal where needed options during
“HI” notations. points in the low range, and/or use during duties future analyzer
different range settings to gain readings replacement
over 2.00.
WD Daily Operations That the WDS operators enter WD staff made Effort to more
Log at times not comments/details in the Daily Operations aware of MECP consistently
showing all general Log for the daily activities performed in recommendation implement into
activities of a job, only the WDS during the operating shift. Log entries
highlights
Security issues at the The equipment room located at the base Mentioned in Brought to
water tower of the water tower to be equipped with an past report management‘s
intrusion alarm; and that the water tower attention for
is provided with security lighting. consideration
1.6. Additional concerns meeting potential compliance or operational requirements
As apart of asset management efforts, significant issues or areas of concern that might be
viewed as potential impact items to operations are listed. These lists contain issues
identified by operational staff and management which might,
pose potential risk with inability to meet compliance and/or operational
requirements,
help prevent equipment failure or down time,
assist with more efficient operations.
(Please also refer to Section 3).
Perth Drinking Water System Summary Report 2020 Page 91.6.1. Drinking Water System
Issue Concern Corrective action taken or proposed
Relevant water computer programs Made progress working to upgrade CPU’s
industry computer updating needed and some of the operating programs. Most of
programs 2020 focus was addressing comms issues
that resulted with Windows 10 upgrades
1.6.2. Water Treatment Subsystem
Issue Concern Corrective action taken or proposed
Building Concern with An engineering study to be done to divert
wastewater amount of “clean “clean wastewater “away from process
generation water” being residue treatment (ie roof drains, coolant
treated water, analyzer sample water, work sinks)
Reservoir isolation Equipment is aged Reservoir valve replacement program
valves and unreliable continued in 2020 with reservoir influent and
bypass valves only replaced. Investigations
into reservoir effluent valve appear complete
replacement will need to be considered.
Process residue Concern for lack of Improvements made to heating measures for
management ops cold temperature outside bag piping and valves. Limited indoor
operations capacity remains a concern during colder
contingency plans temperatures.
Dry Chemical Equipment is With increased unmanned facility operations,
volumetric feeders becoming aged and concern is heighted. Staff have implemented
of concern some remedial actions; however, equipment
style is now outdated, and liquid chemical
options are being considered.
Bulk chemical Proximity of the Investigation into options continue.
storage bulk chemical
storage tanks
Building Some outstanding Condition of roof persists.
infrastructure items identified in Some concerns exist from designated
past reports still substances report.
Facility Security Security fencing Discussed at MECP inspections previously.
and cameras install
consideration to Growing operational infrastructure outside the
monitor building building now exists – need for measures with
exterior areas process residue infrastructure and reservoir
Continue Predictive maint Predictive Maintenance allows the ability to
developing a monitoring is more recognize the onset of degradation before
predictive important with less significant deterioration occurs.
maintenance manned facility
program approach hours.
Perth Drinking Water System Summary Report 2020 Page 10Replacement of Both have become Preliminary investigations into use of
higher volume aged; need to magnetic meter technology to replace existing
flowmeters consider newer venturi and orifice plate use
(Raw water, equipment
Discharge water)
Operational Continual Need to explore amperage meters on various
electrical demand assessing of electrical equipment to alert when improper
electrical needs for supply occurs
upgrading or unit
replacement
High voltage pump New MCC ability to To use existing MCC technology, and
motor monitoring monitor pump incorporate other monitoring equipment to
operations not fully help establish a predictive maintenance
utilized approach for aging pump motors
Further Basic automation The focus of automation needs to continue
automation operational needs addressing more in-depth treatment process
installations and are in place monitoring to allow SCADA to perform a more
upgrading (on/off), but more efficient operations and water quality issue
digital upgrades are alerting.
required to move
forward. Replacing outdated analog circuitry needs to
continue, as a significant majority of the work
remains.
1.6.3. Water Distribution Subsystem
Issue Concern Corrective action taken or proposed
Elevated tank 10” Is faulty and needs Plan to replace in 2021/22, with Elevated tank
fill valve to be replaced is taken out of service for interior
maintenance work
Lack of recent With new road While it is realized that perhaps road work is
road and work, upgrades to not a high priority every year, the issue has
infrastructure work aged distribution been brought to Management’s attention for
system areas might consideration during budgetary discussions.
happen
Perth Drinking Water System Summary Report 2020 Page 11SECTION 2 – SUMMARY OF PLANT FLOWS
2.1. Raw Water (Source water)
Table RW-3 located in the reports Appendix offers an individual daily RW flow expressed
in Liters/day (1000 L = 1 m3).
The table below (RW-1) gives the monthly average RW flow, monthly single day max and
min flows, and the monthly total RW intake flow volume. A comparison of the single day
maximum of the month to the PTTW allowable volume of 9092 m3 is shown.
Table RW-1
2020 Raw Water Volumes
Average Minimum Maximum TOTAL FLOW Daily Maximum % of
Daily Flow Daily Flow Daily Flow PTTW Allowable
(m3) (m3) (m3)
(m3)
Volume
January 2845.2 2305 3496 88,202 38.5%
February 2842.2 2365 3379 82,394 37.2%
March 2802.0 2372 3493 86,862 38.4%
April 2636.5 2225 3155 79,095 34.7%
May 3024.0 2087 4969 93,744 54.7%
June 3425.8 2464 4722 102,775 51.9%
July 3672.9 2686 5053 113,861 55.6%
August 3269.7 2330 4125 101,362 45.4%
September 3056.8 2182 3732 91,703 41.0%
October 2911.6 2123 4842 90,261 53.3%
November 2644.9 2248 3199 79,347 35.2%
December 2657.1 2148 3381 82,370 37.2%
ANNUAL TOTALS avg 2982.32 Min 2087 Max 5053 Total 1,091,976
2.1.1. Average Daily Raw Water Flow:
The monthly average of daily average raw water flow was 2982.32 m³ in 2020, or
approximately 32.80% of the PTTW.
The daily average in 2018 was 3170 m³, followed by 3063 m3 in 2019. Factoring weather
conditions, a slightly lower but still consistent water demand over recent years can be
shown.
Perth Drinking Water System Summary Report 2020 Page 122.1.2 Maximum Raw Water Flow:
The maximum day flow however was on July 28 (5053 m 3), due to overnight catch up of
water production and heavier demand during the day.
The next highest raw water flow days in 2020 occurred during Town hydrant flushing
times, with the second highest being 4969 m³ (May 05), followed by a flow day of 4842 m³
(Oct 14).
Spring flushing (May 4-7) had an average day flow of 4315.5 m³
Fall flushing (October 14-16) had an average day flow of 4183.3 m³
This is relevant as the PTTW maximum of 9092 m3 can be exceeded during water
distribution maintenance work times.
June 23 (4722 m3) was also an abnormally high RW production day, again due to high
water demand and numerous bulk water sales.
2.2. Service Water (Treated Discharged Water)
Below are the Treated Water monthly volumes, noting the high daily flow volume in May
and October can be attributed to Hydrant Flushing week(s). Water main breaks can also
be associated with high treated water flows.
2020 Treated Water Volumes Discharged to Town
Average Minimum Maximum TOTAL FLOW Daily Maximum % of
Daily Flow Daily Flow Daily Flow Design flow
(m3) (m3) (m3)
(m3)
(9090 m3)
January 2762.1 2415 2954 85,626 32.5%
February 2749.8 2326 2941 79,745 32.4%
March 2704.0 2426 2904 83,825 31.9%
April 2554.5 2274 2863 76,635 31.5%
May 2937.8 2191 4600 91,072 50.6%
June 3347.4 2539 4180 100,421 46.0%
July 3634.7 2642 4723 112,677 52.0%
August 3228.8 2315 4083 100,093 44.9%
September 2980.6 2431 3552 89,419 39.1%
October 2805.4 2300 4698 86,968 51.7%
November 2512.8 2310 2749 75,385 30.2%
December 2533.6 2150 3289 78,541 36.2%
ANNUAL TOTALS avg 2895.97 Min 2150 Max 4723 Total 1,060,407
Table TW-1
Perth Drinking Water System Summary Report 2020 Page 132.2.1. Average Daily Service Water Flow:
Annual service water daily average flow
Year 2015 2016 2017 2018 2019 2020
Annual avg
flow m3 3057 2657 2653 3072 3011 2896
The service water daily average water flow was 2895.97 m³ in 2020. Over 5 years (2015-
2019), the average daily service water flow was 2890 m³, making 2020 service water
volumes comparable to recent years.
2.2.2. Service Water Discharge:
Annual service water total flow
Year 2015 2016 2017 2018 2019 2020
Annual avg
flow m3 1,115,473 972,383 967,217 1,122,056 1,099,316 1,060,407
In 2020, the total discharge amount was 1,060,407 m3 to the Town. Over 5 years (2015-
2019), the average annual water discharged was 1,055,289 m³, making it comparable to
recent years.
This volume is relevant to doing future financial projections of water service revenues.
2.3. Plant process water
The WTP Process Wastewater Residue Management involves two individual treatment
processes, direct Geo Bag system deployment, and a separate pre-treatment Backwash
Equalization Tank (BET) system.
Sludge from the settling tanks is typically dense enough for direct processing and sending
to the Geotubes (solids collection geo membrane bags). The geo membrane captures the
solids, and allows “cleaned” water to pass through. The water is discharged back to the
Tay River.
Filter backwash wastewater is directed to a “geo membrane pre-treatment” system, or
Backwash Equalization Tanks (BET). The backwash wastewater contains a higher
percentage of water, opposed to solids. The BET system allows time for sludge
separation through sedimentation, and supernatant removal. The BET supernatant is
discharged to the Tay River sludge is then directed to the Geotubes for treatment.
Backwash wastewater is dechlorinated prior to entering the BETs.
Perth Drinking Water System Summary Report 2020 Page 14The Geotube system is operated manually by operators during normal working days.
Although designed to be an automated process, it was found to be unreliable which
concerns raised as to operating it without staff readily available on-site. BET operations in
2020, for the most part, still also require manual operations by operators. Replacement of
BET tank level sensors (move to radar from ultra-sonic versions) have allowed less
vigilant monitoring, however due to tank design implications, operators are still required to
be on-site during operations.
One significant change to process residue operations occurred in 2019, when the WTP
facility was no longer manned during weekend hours. Given the small Geotube sludge
hopper size, diverting weekend settling tank sludge removal volumes to the BET(s) now
occurs using a separate tank siphon system. There is the opportunity to capture some
supernatant off the weekend settling tank wastewater before the thickened sludge is
transferred back to the Geotube hopper for normal processing.
The settling tank sludge removal system (chains and flights) are becoming aged and soon
in need for replacement consideration. Settling tank cleaning occurs on a regular basis
(spring and fall), utilizing the WTP process residue management processes to process the
sludge.
The accumulation of “clean wastewater” from non-process water sources (such as roof
drains, work sinks, analyzer bypass flows, engine and pump coolant water) continues to fill
BET(s) and use up residue processing time and resources. As mentioned in previous
DWS Summary Reports, a feasibility study should be considered to explore options to
divert this water away from the process residue management system and possibly to
sanitary sewer discharges.
2.3.1. Waste Volumes
Annual total Geo-tube influent flow
Year 2017 2018 2019 2020
Annual total
flow m3 13,572 14,250 13,528 12,867
In 2020, a total volume of 12,867 m3 was directed to the Geo-tubes (solids collection
membrane bags). This was down from previous years possibility due to operational
changes, the volume being generated annually can be influenced by many uncontrollable
operational factors, such as raw water conditions and rainfall accumulation
(overabundance or lack of). Of note was the higher 2018 volume, when BET
commissioning did occur.
Annual total filter backwash wastewater generation
Year 2016 2017 2018 2019 2020
(no air scour)
Annual total
flow m3 (est) 14,131 9,155 11,391 10,934 10,377
Perth Drinking Water System Summary Report 2020 Page 15Backwash wastewater generation for 2020 was estimated at 10,377 m3. This was comparable to past years, and continues to show operations optimizing efforts (given a single backwash may use 1,000 m3). GAC (filter media) testing in 2020 is becoming less effective and may require more backwashing in 2021. GAC replacement is scheduled over the next couple years. Of significance is the amount of backwash wastewater generation (est 10,377 m3) in comparison to the BET supernatant discharging volume of 25,673 m3. This apparent difference of only supports the need for a feasibility study to divert “clean” non-process wastewater away from the BET wastewater stream. 2.3.2. Geo tube membrane bag use To start 2021, operations were switched to greenhouse bag use by January 19. This was smaller bag size (less length) than in 2019, in efforts to avoid bag damaging. The greenhouse bag was used exclusively until mid April, where rotation to the outer bag 2 was done on warmer days. The greenhouse bag was taken out of service on June 11 with approx. 5151 m3 of geo hopper sludge directed to it. On October 21, the greenhouse bag was removed with approximately 160 metric tonnes taken to landfill. The outside bag #1 was just put into service late in 2019, and was in use start 2020. It was not used on a regular basis between Jan 19 and July 14. In July, it became the primary use bag until mid December, while other bags were in drying stages preparing for removal. In 2020, it had ~6413 m3 of geo hopper sludge directed to it (or ~75% of assumed 8500 m3 bag capacity). The other outside bag #2, overwintered to start 2020 in a relative filled state (6332 m3), before topping up efforts in April 2020. It was taken out of service on July 14 with approximately 8454 m3 of geo hopper sludge directed to it. On November 24, the outside bag #2 was removed with approximately 250 metric tonnes taken to landfill. The replacement bag was put into service December 15, and used to start 2021. Bag capacities assumptions are very difficult and only based on previous years’ volumes sent to the bags, as several factors significantly impact bag performance (sludge density, bag dewatering ability, bag conditioning, bag durability). Using 8500 m 3 as a bag capacity reference number, it gives a reference point when assessing outer bag use. In 2020, replacement tarps for some outside bag influent feed lines were replaced, along with some heat trace cable replacement after thermal imagery testing. A thermal blanket was installed around the geo influent feed line valves to help protect from freezing. Perth Drinking Water System Summary Report 2020 Page 16
SECTION 3 – SUMMARY OF DRINKING WATER SYSTEM ABILITIES
3.1. Water Treatment Ability
The Perth water treatment plant continues to maintain a strong position in supporting its
ability to provide a reliable supply of safe, clean drinking water to its community. Funding
reserves are maintained in case of an operational emergency or unexpected major
breakdown.
3.1.1. Disinfection ability
Disinfection of the drinking water is ultimately achieved through two points of application –
primary disinfection – dosed as water enters the clear well; and secondary disinfection –
dosed at the treated water discharge point. Both critical treatment processes have
redundancy in the pumps as well as the dosage lines.
Varying raw water conditions require operators to adjust and control chemical dosages to
meet regulations in a cost-effective manner.
It should be noted that many factors contribute to the overall disinfection process,
including pre-treatment, coagulation and pH control. Of most importance is the daily CT
calculation. The CT value is the product of the concentration of a disinfectant and the
contact time with the water being disinfected. WTP operations in 2020 continued to
exceed the legislated CT operational requirements, supporting the ability to meet proper
disinfection needs.
Another critical factor for proper disinfection is turbidity. Water with high turbidity can
impede the disinfection process, and why disinfection occurs after filtration. The objective
is to maintain filter effluent turbidity of < 0.300 NTU for 95% of the time. The Perth WTP
exceeded the 0.300 target on each filter for minimal time over the entire year, 8 minutes in
total for filter #1, and 17 minutes in total for filter #2. A typical daily average of 0.03 to 0.04
NTU is being realized. Putting this in perspective, the reportable level for filtrate water is 1
NTU after 15 minutes, whereas at 5 NTU water can be visibly cloudy, and murky water
found around 25 NTU.
Considerations with disinfection abilities might be,
a need to investigate primary disinfection chemical metering equipment
alternatives, and while the existing is currently reliable, it is becoming more cost
prohibitive when replacing parts,
replacement of sodium hypo chemical delivery lines, and
a need to explore disinfection sampling pump options.
3.1.2. Chlorine Dioxide use
Chlorine dioxide continues to be generated seasonally on site and plays an important role
in achieving disinfection while mitigating the formation of chlorine disinfection by-products
Perth Drinking Water System Summary Report 2020 Page 17such as THM’s and HAA’s. These disinfection by-products are suspected carcinogens and
are commonly formed when high doses of chlorine gas or sodium hypochlorite react with
raw water heavily laden with organic matter. Chlorine dioxide use is uncommon among
water treatment facilities due to chemical cost however the advantage of a “cleaner”
disinfection process with less by-product formation is worth the extra cost during extreme
seasonal water quality challenges seen in Perth.
As well, the renewal of the municipal Drinking Water License saw the additional sampling
requirement of Chlorates and Chlorites added as a quarterly sampling requirement. The
availability of an accredited laboratory to perform the tests is limited, and in-house lab
sample preparation has become even more difficult with short delivery time restrictions.
Considerations with continued Chlorine Dioxide use
The Chlorine dioxide system was only exercised in 2020 briefly (~1400 m3 LLP ops)
during June 7-8 preparation to take the clearwell out of service.
With the less chlorine dioxide use, stock chemical stock concentrations are
degrading in their containers, so more concentrate is needed to create the same
amount of chlorine dioxide, and possibly higher by-product creation risk.
Plans are to try and exercise the system more frequently in 2021 to use up old
chemical stock and assess equipment reliability.
3.1.3. Coagulation abilities
The water treatment plant employs a premium coagulant called PAX XL-6 to aid in the
flocculation and sedimentation of suspended solids in water prior to filtration. Although
more expensive than conventional coagulants such as aluminum sulphate, product usage
is reduced, and it outperforms other less expensive chemicals at certain critical
temperature ranges. Winter months and the associated cold-water temperature and
density present the most difficult conditions for the coagulant to settle the solids. Our
licence allows for pH enhancement (use of HCl) in situations of high pH or alkalinity raw
water conditions that make floc formation difficult.
In 2020, the new motor driven diaphragm pump used for metering coagulant feed delivery
operations proved reliable. In late 2020, a similar second motor driven diaphragm was
purchased, and to be put into 2021 service upon spring delivery. The expense of the new
pumps is easily offset by the cost savings associated with not having to continual
purchase replacement peristaltic tubes for coagulant feeds.
Consideration with current coagulation setup might be,
to investigate more cost-effective alternatives, and/or seasonal product alternating
options,
to continue the switch to the motor driven diaphragm metering pumps, along with
back pressure creation devices and flow dampeners
Perth Drinking Water System Summary Report 2020 Page 18 the existing flash mixer is adequate for current operations, it is becoming aged and
consideration of an in-line static mixer needs to factor into any future RW header
planning.
consider feed line alternatives, and installation of a backup coagulant feed line.
3.1.4. Flocculation and sedimentation abilities
The flocculation equipment is becoming aged and in need of frequent repairs. Drive shaft
bearing replacement efforts have been completed, and maintenance inspections regularly
occur. Parts of the flocculation were discovered to have metal fatigue due to rust and
corrosion, and probable complete replacement will be required in the upcoming two years.
Cracking along the floc tank walls has been noted, cemented over in 2020, but still in need
of inspection by qualified personnel.
Cement repair work to an older cracked wall situation in settling tank 1 (~ 2002) was
resealed with hydraulic cement in June 2020. Inspection in October 2020 indicated repair
work was still holding.
In June 2020, emergency repair work to the aged water supply line supports was done in
settling tank #1. Further completion of the work (and any required in settling tank 2) will
be scheduled for 2021.
Sludge removal equipment in the sedimentation (settling) tanks has been continually
repaired over the past years, mainly the PPE thermoplastic chain links becoming fatigued
and worn. Cost assessment was undertaken in 2019, and while stainless steel is an
option, replacement with PPE thermoplastic would be more cost efficient and provide less
stress on the existing infrastructure (supports, drive shafts, motors).
Considerations with Floc and Sedimentation processes might be,
Complete repairs of the settling tank water supply line, and continue assessment of
cracking along settling and floc tank(s) walls.
Continue with an inspection and preventative maintenance program for floc drives
using outside machinist contractors.
Implement a plan for flocculation tank structural repair work (2020-2021)
Implement a sludge removal chain replacement plan
3.1.5. pH adjustment (use of lime)
Following the coagulation and disinfection processes, where the pH of the water is
lowered through the addition of chemicals, hydrated lime needs to be mixed in the
clearwell to return the pH to a range of 7.1 to 7.3. This range is desired to ensure the
water within the distribution system is close to neutral and thereby not aggressive in the
deterioration of the distribution network as well as homeowner plumbing and fixtures.
Perth Drinking Water System Summary Report 2020 Page 19Preliminary investigations into considering use of liquid pH adjustment chemical have
occurred, with current lower WTP water production volumes posing complications.
Additional option exploring needs to continue in 2021.
3.1.6. Fluoridation abilities
Granular fluoride is added in the same application area as the lime. As the volumetric
feeder is aged, a continual feed is not possible due to the low dosage requirements. As a
result, a “feed and starve” approach is required to keep residual levels in the targeted and
compliant range. Based on grab sampling, this operational approach has appeared
effective enough. Initial investigations into conversion to liquid fluoride addition revealed
conversion complications, and additional options need exploring in 2021.
Considerations with future fluoridation practices might be,
Include liquid chemical dosing into any future planning,
Implement a 5-year reassessment program for continued fluoride use with goal of
needs re-evaluation in 2025.
3.1.7. Pumping capacity
The existing pumping capacity meets the needs of the facility and the water demand from
the drinking water system. The HLPs adequately operate with the SCADA to supply the
Town’s distribution system and maintain sufficient water pressures. The LLPs operate
sufficiently to move enough water through the facility to meet the demands while
maintaining process design requirements.
LLP (low lift pumps, raw water supply)
Flows on the smaller capacity LLP’s continue to drop off slightly. All indications continue
to appear the primary source is not electrical, and possibly mechanical somehow.
In January 2020, with Hewitt’s (pump machinists) on-site doing other work, the impeller
spacing on LLP3 was adjusted to see what difference of flows happened. It was found the
impeller was likely showing signs of wear, and adjusted to get the best flow out of the
pump.
In February 2020, Tower Electronics was on site with a portable magmeter to measure
LLP flow in the pipes. Flow was measured just after the in-line orifice flowmeter. The
results found were flow rates more comparable to the expected pump capacities, and up
to 10 L/s than what the current flow meter was giving. While the pipe composition and
diameter can cause some discrepancies, it did draw the older differential flow meter
readings a bit into questions. If the RW orifice flowmeter plate were starting to plug up, it
could be restricting flow at times and causing increased head pressure at the pump.
Increased TDH (total Dynamic Head) could easier cause lower flows rates, and more
noticeable in the smaller LLP capacity pumps.
Perth Drinking Water System Summary Report 2020 Page 20Nevertheless, the existing LLP pumps suffice for the current needs. Should either of the
lower sized LLP be in the need of replacement, a slightly larger capacity pump could
supply a better midrange operating range. The two existing pumps (~ 60-66 L/s) can
typically require 13-16 hours of daily operation to meet the current water demand. The
new MCC does allow the possibility for a reassessment of variable speed drives (VSD).
The raw water rate control valve and actuator needs repair and/or replacement. During
automation implementation, it was noted the rate control valve was failing at times. This
issue has been mentioned in past Summary reports, with only general conversations with
contractors and very preliminary planning on project feasibility. If the raw water orifice flow
meter was needed to be upgraded to an in-line magmeter (current industry standards),
extensive header work will need to occur, including any valve replacements at the time. To
take the raw water header out of service, significant operational planning would need to
occur, and high project expenditures expected.
Considerations with LLP pumping capacity might be,
To continue to use specialized machinists in performing a predictive management
approach for both LLP and HLP operations, and an enhanced preventative
maintenance program for pump operations (oil changing, packing changing,
bearings inspection, check valve inspections, pressure relief valve inspections)
To further investigate RW orifice flowmeter as a LLP reduced pump capacity
source,
To further investigate RW rate control valve issues, and
To follow through with a 2020 commitment to purchase a 10 HP motor to be readily
available as a replacement for either LLP2 or LLP3 operations.
HLP (High lift pumps, town water supply)
Both HLP #2 and #3 have undergone recent repair and equipment replacement in recent
years. HLP#1 has shown no significant operational cause for concern, with the diesel
engine still in a serviceable and reliable state.
The emergency by-pass discharge is becoming aged, and should be the focus of a
detailed operational condition assessment in the near future.
Pump Maintenance
Specialized machinists were brought in to perform the annual pump and motor
maintenance on both LLP and HLP’s. This was part of the initiating a preventative
maintenance approach for the pump operations, where a wider scope of work was done to
help identify problems well before they might occur.
Considerations with HLP pumping capacity might be,
To continue to use specialized machinists in performing a predictive management
approach for both LLP and HLP operations, and an enhanced preventative
Perth Drinking Water System Summary Report 2020 Page 21maintenance program for pump operations (oil changing, packing changing,
bearings inspection, check valve inspections, pressure relief valve inspections)
3.1.8. Process Wastewater Residue Management ability
In 2020, efforts were made to try and mitigate concerns from previous Summary reports,
mainly that,
the inability to use outside geo-bags during moderately cold weather (>-10oC) has
been addressed with increased heat trace cables and insulated tarps wrapping the
water pipes; and insulating blankets over the outer water feed line valves; and,
in gaining longer outside times, it is hoped existing greenhouse space might suffice.
Ability to treat BET sludge
Despite improvements made to tank level sensors, BET operations continue not to be the
fully automated treatment process as initial designs suggested. It still requires significant
staff time to operate the system, and does impact the scheduling of other WTP operational
activities. Timing of the backwashes is probably most important, juggling weekend settling
tank sludge processing, allowing sufficient settling time to remove supernatant, and have
BET tanks empty again for weekend sludge acceptance.
Geo bag operations
The larger circumference geo bags seem to work satisfactory outdoors; however, the pad
area does become full utilized with some water escaping away from the catchment area.
The smaller greenhouse bag size does limit our capacity, but allows clearance all around it
so that weeping promotion of the bag can occur.
Despite all the heat trace cables and other measures taken to continue to treat to outside
bags during colder temperatures, our vulnerability to continued greenhouse operations is
exposed during a prolonged deep freeze or greenhouse bag failure.
Considerations with process wastewater residue management ability might be,
additional greenhouse capacity needs to be a priority consideration for the future to
allow,
o continued operations during extended colder temperature weather, and
o the ability to have two smaller bags to exist, giving a viable greenhouse bag
damage contingency plan
Security measures to be implemented around Phase II in-ground access areas and
outside geo bag deployments.
Perth Drinking Water System Summary Report 2020 Page 223.1.9. Computer System In 2020, significant amount of time and expenses were spent addressing SCADA communications and off-site alarm notification programming issues (as was in 2019). Both Wonderware (SCADA) and WIN911 (alarm notification) programming had numerous complications and failures to sync with the newly installed Windows 10 operating platform. While computer operating platforms (such as Windows) can make rapid development and advancements, actual utility software change and adaption is much slower. This needs to be strongly considered where future “Windows upgrading” efforts are being scheduled (specifically if it is to be a 3 year computer replacement plan). With the 2020 focus in trying to get SCADA operations back to previous year’s reliability, continuing with operations automation and instrumentation installs were delayed. Some digitalized network mapping of SCADA and MCC components was done in 2020, with more to be done in the future. 3.2. Water Taking Ability The WTP is operating well within the PTTW limits. The Permit to Take Water (#5464- 6MHL84) authorizes the municipality to take water with maximum volumes regulated for both litres/min as well as litres per day. This Permit was renewed in the 2016 year and will expire again in 2026. Raw Water pump capacities determine these figures (6,360 l/min (106 L/s) flow; and 9,092 m3/day). The higher raw water flows in 2020 are still mainly attributed to Town hydrant flushing exercises (4969 m3 on May 05, and 4842 m3 on October 14). The maximum day flow however was on July 28 (5053 m 3), due to overnight catch up of water production and heavier demand during the day. June 23 (4722 m3) was also an abnormally high RW production day, again due to high water demand and numerous bulk water sales. High volume weeks noted during July 6-10 (July 7 with 4,755 m³, with an average of 4383.0 m³/day over the five days). A second higher volume time noted over July 21-25, (July 21 at 4450 m3, with averaging of 4095.2 m³/day over five days). Both these times are reflective of use during hot dry climate times, with peak days just over 50% of the PTTW allowable volume for normal operations. A more realistic daily maximum during a typical operating might be 3700 to 4200 m3 range in the summer, and 2500-3200 during winter months. 3.3. Water Storage Ability Perth Drinking Water System Summary Report 2020 Page 23
The reservoir storage capacity appeared to be sufficient to meet the disinfection contact
time needs, as well as providing required water supply for domestic, industrial, and fire
fighting purposes.
The reservoir area around the reservoir influent valve was cleaned by a diving crew on
June 09, 2020, when the reservoir bypass valve replacement was being done. The
clearwell at the same time was drained, cleaned, and inspected at the same time.
There was an incident in August 2020 where significant damage was done to the primary
elevated tank signal circuitry. It is felt a lightning strike contacted the copper bell line used
to signal communications, and the two transmitting units on either were damaged.
Operations were switched over to the back up transmitters and tank level signals were
restored. The damaged transmitters were sent out for repairs, where some electrical
components required replacing.
A new and stronger UPS unit was installed at the Elevated Tank to help provide a more
reliable and continuous signal for SCADA.
Elevated tank maintenance work (requiring draining) will need to be scheduled in the next
couple years. It is felt a needed distribution valve replacement at the elevated tank could
be done at the time.
Regular maintenance and emergency repairs occurred within the distribution system
including mains, services and hydrants.
Reservoir valve replacement program
Reservoir valve replacement program was resumed in 2019, once the Process
Wastewater Residue Management Phase II construction was finalized. The initial cost
estimates of 2015 have been well surpassed, any streamlining efforts to get the most
economical and feasible solutions possible available, including consideration of the do-
nothing option for parts of the initial program objectives.
To date, the following has been done,
The reservoir influent valve has been replaced.
The reservoir bypass valve has been replaced (although still remains blanked off)
The reservoir effluent valve has been cleaned and inspected, with replacement the
more feasible option as repair work seems unlikely. Removal difficulties will be very
significant.
The secondary reservoir effluent was briefly cleaned and assessed, with
replacement the likely option.
The isolation valve between service wells 1 and 2 can be operated, however ability
to completely seal off is not fully known at this time.
High priority items in 2020 for the reservoir involve,
Perth Drinking Water System Summary Report 2020 Page 24 Assess options (possible Engineering consulting) regarding proceeding with the
reservoir effluent valve replacement and/or repair,
Inspect and assess the secondary reservoir effluent valve (to Service well #2), and
Inspect and access the service well 2 isolation valve.
3.4. Water Treatment and Distribution Personnel
Water Treatment Plant (WTP)
The WTP is a Class III facility. Basic automation implementation has allowed the facility to
be operated with 8 hr normal workday shifts (weekends unmanned). During upset RW
conditions, or if operational concerns exist, additional manned shifts are scheduled to
allow more on-site “hands on” activities and monitoring.
While the WTP shift scheduling becomes less, the workload associated with maintaining
automated WTP operations increases. Key to this increased unmanned facility times, is
the reliance of WTP operators to be on-call for immediate response to any WTP
operational alarms, either through remote site communications or an actual site visit
depending on the situation severity. Shifts and duties are mainly rotated amongst two full
time operators, and the Lead Hand filling in as required. All WTP staff maintain WT Level
III certifications.
Water Distribution (WD)
The Distribution system is a Class 1 facility and is maintained by a Lead Hand and five
operators, who rotate through other departments within the organization. The Lead Hand
possesses a level III certification in distribution and supply. Two (2) other operators have
level II certification, one operator with level I certification, one operator with operator in
training status, and one new employee with no certification to start 2021.
Mention needs to be made that DWS staff also serve as WWS (wastewater system)
operators. Distribution staff maintain the WWS collection system and its pumping stations.
WTP staff are required to maintain the WWT facility, including the lagoon operations as
well as a the SAGR facility and pumping station.
Perth Drinking Water System Summary Report 2020 Page 25Appendix
4.1 Appendix Table 1 – Summary of Flows January 1, 2020 to December 31, 2020
Perth Water Treatment Plant
PTTW maximum allowable flow rate: 9,092 m3/ day
Discharge (Service)
Raw water (m3)
Water (m3)
Monthly
Monthly
Monthly Daily Monthly Daily
Month Total
Average Flow Total Flow Average
Flow
Flow
January 2845.2 88202 2762.1 85626
February 2841.2 82394 2749.8 79745
March 2802.0 86862 2704.0 83825
April 2636.5 79095 2554.5 76635
May 3024.0 93744 2937.8 91072
June 3425.8 102775 3347.4 100421
July 3672.9 113861 3634.7 112677
August 3269.7 101362 3228.8 100093
September 3056.8 91703 2980.6 89419
October 2911.6 90261 2805.4 86968
November 2644.9 79347 2512.8 75385
December 2657.1 82370 2533.6 78541
Year Average 2,982.32 90,988.0 2,895.97 88,367.3
Year Total 1,091,976 1,060,407
Perth Drinking Water System Summary Report 2020 Page 264.2 Appendix Table 2 – Historical Average Daily Treated Water Flow (m³)
Perth Water Treatment Plant
2020 2019 2018 2017 2016 2015 2014
JAN. 2762 2972 2982 2,381 2,502 2,872 3,211
FEB. 2750 3036 2890 2,454 2,571 3,290 2,980
MARCH 2704 3047 2961 2,491 2,455 3,298 3,053
APRIL 2555 3038 2983 2,586 2,471 3,157 3,247
MAY 2938 3049 3363 2,495 2,931 3,392 3,003
JUNE 3347 3062 3268 2,836 2,996 3,002 3,285
JULY 3635 3469 3602 2,796 2,954 3,048 3,292
AUG. 3223 3228 3269 2,837 3,024 3,015 3,099
SEPT. 2981 2902 2947 2,886 2,694 2,979 2,992
OCT. 2805 2912 2982 2,830 2,603 2,998 2,901
NOV. 2513 2707 2840 2,568 2,372 2,852 2,693
DEC. 2534 2711 2776 2,681 2,300 2,784 2,642
MAXIMUM 3,635 3,469 3,602 2,886 3,024 3,392 3,292
MINIMUM 2,513 2,707 2,776 2,381 2,300 2,784 2,642
AVERAGE 2,896 3,011 3,072 2,654 2,656 3,057 3,033
Perth Drinking Water System Summary Report 2020 Page 274.3 Appendix Table 3 - 2020 Raw Water Taking
Town of Perth WTP - Daily Raw Water Taking Volumes (L) (PTTW capacity of 9092 m3)
2020
Day January February March April May June July August September October November December
1 2,305,000 2,830,000 2,761,000 2,830,000 2,911,000 2,984,000 3,609,000 2,649,000 3,263,000 2,901,000 2,913,000 2,612,000
2 2,666,000 2,685,000 2,719,000 2,857,000 2,402,000 2,577,000 3,578,000 2,330,000 3,732,000 2,654,000 2,472,000 2,969,000
3 2,576,000 2,918,000 3,493,000 2,390,000 2,570,000 3,455,000 3,516,000 2,897,000 2,971,000 2,364,000 3,199,000 2,521,000
4 2,787,000 3,023,000 2,959,000 2,582,000 4,328,000 3,143,000 3,074,000 2,546,000 3,320,000 2,447,000 2,507,000 2,901,000
5 2,623,000 3,233,000 2,885,000 2,551,000 4,969,000 2,897,000 3,498,000 3,786,000 2,891,000 3,263,000 3,011,000 2,340,000
6 3,115,000 2,365,000 2,683,000 2,756,000 3,994,000 2,707,000 4,286,000 4,125,000 2,612,000 2,906,000 2,696,000 2,634,000
7 2,490,000 2,774,000 3,059,000 2,754,000 3,971,000 2,665,000 4,755,000 3,770,000 2,187,000 2,852,000 2,499,000 2,557,000
8 3,496,000 2,956,000 2,435,000 2,987,000 2,382,000 3,586,000 4,367,000 2,656,000 3,275,000 3,182,000 2,530,000 2,629,000
9 2,620,000 2,494,000 2,758,000 2,437,000 2,488,000 3,233,000 4,707,000 2,713,000 3,263,000 2,567,000 2,631,000 2,727,000
10 2,999,000 2,747,000 3,377,000 2,393,000 2,182,000 3,943,000 3,800,000 3,909,000 3,608,000 2,777,000 2,987,000 2,739,000
11 2,615,000 3,379,000 2,470,000 2,503,000 2,746,000 2,796,000 3,024,000 3,759,000 2,885,000 2,145,000 2,688,000 2,840,000
12 2,734,000 2,989,000 2,940,000 2,349,000 2,639,000 3,130,000 2,751,000 3,742,000 2,366,000 2,790,000 2,926,000 2,567,000
13 2,842,000 2,903,000 2,758,000 2,526,000 2,964,000 2,763,000 3,131,000 3,736,000 2,824,000 4,621,000 2,248,000 2,148,000
14 3,400,000 2,848,000 2,769,000 2,668,000 2,752,000 2,464,000 3,627,000 3,739,000 3,109,000 4,842,000 2,815,000 2,980,000
15 2,850,000 2,496,000 2,906,000 3,155,000 2,880,000 3,330,000 4,150,000 3,418,000 3,464,000 4,160,000 2,328,000 2,708,000
16 2,610,000 2,710,000 2,807,000 2,646,000 2,394,000 4,083,000 3,576,000 3,066,000 3,428,000 2,948,000 2,686,000 3,086,000
17 2,952,000 2,473,000 2,685,000 2,506,000 2,087,000 4,200,000 3,696,000 3,328,000 3,229,000 2,123,000 2,590,000 3,381,000
18 2,833,000 3,025,000 2,747,000 2,541,000 2,924,000 4,695,000 3,158,000 3,599,000 3,130,000 2,748,000 2,826,000 2,872,000
19 2,782,000 3,154,000 3,086,000 2,419,000 2,694,000 4,563,000 2,844,000 3,443,000 2,529,000 2,279,000 2,576,000 2,385,000
20 3,132,000 2,788,000 2,606,000 2,805,000 3,232,000 3,637,000 3,518,000 3,395,000 2,182,000 3,026,000 2,779,000 2,695,000
21 2,753,000 2,900,000 2,717,000 2,568,000 3,550,000 3,669,000 4,450,000 3,173,000 3,017,000 2,659,000 2,473,000 2,697,000
22 2,893,000 2,681,000 2,627,000 2,937,000 3,142,000 3,556,000 4,309,000 3,075,000 3,558,000 3,386,000 2,252,000 2,705,000
23 2,976,000 2,696,000 2,655,000 2,558,000 2,665,000 4,722,000 3,492,000 2,955,000 3,499,000 3,260,000 2,492,000 3,123,000
24 2,813,000 2,897,000 2,987,000 2,967,000 2,859,000 3,167,000 4,380,000 3,113,000 3,248,000 2,195,000 2,731,000 2,390,000
25 2,837,000 3,335,000 2,680,000 2,225,000 3,016,000 3,519,000 3,845,000 3,523,000 2,883,000 2,625,000 2,769,000 2,360,000
26 2,914,000 2,712,000 2,508,000 2,395,000 3,966,000 3,576,000 3,095,000 3,728,000 2,679,000 2,885,000 2,656,000 2,168,000
27 2,830,000 2,755,000 3,040,000 3,061,000 3,572,000 3,203,000 3,544,000 3,243,000 2,812,000 3,189,000 2,581,000 2,460,000
28 2,836,000 2,888,000 2,372,000 2,439,000 2,857,000 3,176,000 5,053,000 3,410,000 3,267,000 2,654,000 2,301,000 2,568,000
29 3,019,000 2,740,000 2,487,000 2,648,000 3,068,000 3,713,000 3,014,000 2,562,000 3,501,000 2,720,000 2,648,000 2,757,000
30 3,095,000 2,777,000 2,642,000 2,681,000 3,865,000 2,686,000 2,792,000 2,971,000 2,754,000 2,537,000 2,437,000
31 2,809,000 3,109,000 2,859,000 3,328,000 3,182,000 2,339,000 2,414,000
Minimum 2,305,000 2,365,000 2,372,000 2,225,000 2,087,000 2,464,000 2,686,000 2,330,000 2,182,000 2,123,000 2,248,000 2,148,000
Maximum 3,496,000 3,379,000 3,493,000 3,155,000 4,969,000 4,722,000 5,053,000 4,125,000 3,732,000 4,842,000 3,199,000 3,381,000
Average 2,845,226 2,841,172 2,802,000 2,636,500 3,024,000 3,433,900 3,672,935 3,269,742 3,056,767 2,911,645 2,644,900 2,657,097
Monthly
total 88,202,000 82,394,000 86,862,000 79,095,000 93,744,000 103,017,000 113,861,000 101,362,000 91,703,000 90,261,000 79,347,000 82,370,000
Running
Year total 88,202,000 170,596,000 257,458,000 336,553,000 430,297,000 533,314,000 647,175,000 748,537,000 840,240,000 930,501,000 1,009,848,000 1,092,218,000
Comparison of monthly totals to PTTW %
month day
max (% 38.5% 37.2% 38.4% 34.7% 54.7% 51.9% 55.6% 45.4% 41.0% 53.3% 35.2% 37.2%
PTTW)
Monthly day
avg (% of 31.3% 31.2% 30.8% 29.0% 33.3% 37.8% 40.4% 36.0% 33.6% 32.0% 29.1% 29.2%
PTTW)
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