appendix c-5 treated water storage and …...this technical memorandum (tm no. 5) pertains to the...

APPENDIX C-5

TREATED WATER STORAGE AND PUMPING

POINT PLEASANT WATER TREATMENT PLANT EXPANSION

TECHNICAL MEMORANDUM NO. 5

TREATED WATER PUMPING AND STORAGE

May 2009

Submitted by:

In Association with:

1101 Prince of Wales Drive, Suite 330

Ottawa, Ontario K2C 3W7

JLR 22575

Utilities Kingston Point Pleasant Water Treatment Plant Expansion Technical Memorandum No. 5 – Treated Water Pumping and Storage

J. L. Richards & Associates Limited JLR 22575 CH2MHILL Canada Limited i May 2009

TABLE OF CONTENTS Page 1.0 INTRODUCTION...............................................................................................................1 2.0 HIGH LIFT PUMPING STATION ...................................................................................... 2 3.0 EXISTING HYDRAULIC RESTRICTIONS........................................................................ 8 4.0 ON-SITE STORAGE ....................................................................................................... 10 5.0 CONCLUSION ................................................................................................................ 11

TABLES

1 SUMMARY OF EXISTING HIGH LIFT PUMPS 2 PUMP CONFIGURATION OPTION NO. 1 3 PUMP CONFIGURATION OPTION NO. 2 4 PUMP CONFIGURATION OPTION NO. 3

APPENDICES 1 Existing Layout Sketch 2 Existing High Lift Pump Curves 3 Projected System Curves for Various Study Years 4 Proposed Pump and System Curve 5 Partial Existing Plant Hydraulic Profile 6 Preliminary General Arrangement for High Lift Pumping Station


J. L. Richards & Associates Limited JLR 22575 CH2MHILL Canada Limited 1 May 2009

1.0 INTRODUCTION

Utilities Kingston retained J.L. Richards & Associates Limited, in association with CH2MHILL

Canada Limited, to complete a Class Environmental Assessment (Class EA) to expand the

treatment capacity at the Point Pleasant Water Treatment Plant (WTP), previously referred to as

the Kingston West WTP, in order to implement the June 2007 Master Plan for Water Supply for

the City of Kingston Urban Area. This Master Plan identified works that will be required to meet

existing and future demand increases within the urban area of Kingston. The Master Plan EA

determined that the expansion of the Point Pleasant WTP is of high priority. The purpose of this

current Class EA study is to identify the preferred strategy for meeting future water treatment

needs at the Point Pleasant WTP.

The Point Pleasant WTP, located at 80 Sunny Acres Road, supplies water to the Kingston West

water distribution system, and currently has a rated capacity of 45.5 megalitres per day (ML/d).

This Class EA study will examine alternative strategies to increase the functional capacity of the

WTP to 80 ML/d by the year 2012 in order to accommodate demand. With ever more stringent

treated water quality requirements, and an expanding Kingston population, there may be a need

to improve both the capacity and treated water quality of the existing facility.

A number of important issues are being reviewed and addressed through five Technical

Memoranda prepared as part of the Class EA process, as summarized below:

Technical Memorandum No. 1: Source Water Quality and Drinking Water Treatment Objectives

Technical Memorandum No. 2 Existing Facility Condition Assessment and Treatment

Limitations Technical Memorandum No. 3 Low Lift Pumping Station Upgrade Technical Memorandum No. 4 Treatment Process Expansion Technical Memorandum No. 5 Treated Water Pumping and Storage Upgrade

This Technical Memorandum (TM No. 5) pertains to the existing High Lift Pumping Station, on-

site treated water storage, as well as the upgrades necessary to meet future pumping and

storage requirements. Discussions on the interconnecting hydraulic limitations are also

presented.



The existing high lift pumping system and storage facilities were discussed as part of the

condition assessment in Technical Memorandum No. 2. Recommendations include:

Reservoir volume will likely need expansion (TM No. 5).

Impact of high lake levels on reservoir and contact tank slab to be investigated (TM No. 5).

Increase firm high lift pumping capacity (TM No. 5)

Investigate a dual high lift discharge header arrangement (TM No. 5).

Ensure floor drains do not discharge to the lake (Preliminary Design).

Clearwell capacity needs to be verified depending on selected treatment technology

adopted (Preliminary Design).

Investigate having the backwash pumps draw from individual clearwells to allow clearwell

isolation (Preliminary Design).

Consider modifying the clearwell fill point and chlorination point to increase contact time

(Preliminary Design).

Review hydraulic pinch points to allow greater capacity through the contact tanks (TM

No. 5).

2.0 HIGH LIFT PUMPING STATION

The High Lift Pumping Station (HLPS) is currently integral to the Pump Building and draws from

the reservoir. Refer to Appendix 1 for a simple site diagram of the existing facility. The wetwell

is divided into two independent smaller wells; one well has an approximate capacity of 275 m³

while the other has an approximate capacity of 195 m³. A sluice gate and butterfly valve provide

for well isolation. Four (4) dual stage vertical turbine pumps and one (1) triple stage vertical

turbine pump draw from these wells; capacities are summarized in Table 1. Most of the pumps

date back to the original 1977 construction. Despite their age, the pumps appear to be well

maintained. Performance of these pumps was assessed through on-site hydraulic testing, where

the actual operating point of the pump was determined to be consistent with the published pump

curve. The total pumping capacity of the five pumps is 95,374 m³/d with a firm capacity (largest

pump out of service) of 68,120 m³/d. During a power outage, diesel drives are available for two

pumps to provide a total capacity of 40,876 m³/d and a firm capacity of 13,622 m/³d.



Table 1- Summary of Existing High Lift Pumps Pump ID Manufacturer Rated

Capacity (m3/d)

TDH (m)

NPSHr (m)

Type Drive (type/HP)

HLP#1 (1977) Fairbanks Morse

13,622 70.4 NA Vertical Turbine

Electric (200hp)

HLP#2 (1977-2001)

Fairbanks Morse


Electric (200hp)



Electric/Diesel (285 hp)


27,254 70.4 8.1 Vertical Turbine

Electric (400 hp)



Diesel (420 hp)

Refer to Appendix 2 for the existing pump curves.

.1 High Lift Pumping Capacity Requirement

The proposed WTP expansion will require that the high lift pumps be upgraded to meet the

projected 20 year maximum day demand of 80,000 m³/d, up from its current capacity of

45,000 m³/d. In order to determine the impact on storage and pumping systems, dynamic

modeling of the distribution network was undertaken by Utilities Kingston in association with

CH2MHILL. To best define the pumping range required over the course of the 20 year study

period, three demand scenarios were modeled corresponding to the maximum demand for years

2006, 2016 and 2026. System curves generated from results of the model are included as part

of Appendix 3. From these results it can be concluded that the theoretical maximum discharge

head varies from approximately 75 m in 2006 to approximately 90 m for the 2026 study year.

It has been reported that due to the age and the condition of the water main in the vicinity of the

Point Pleasant WTP, the operating pressure should not exceed 690 kPa or 70 m. Current

operating discharge pressures are very close to this value and pressure surges have reportedly

exceeded it. This issue will need to be further addressed because, as indicated above, future

supply pressure will significantly surpass this limitation. Possible solutions requiring further study

may include:

1. Locate deteriorated sections of water main and perform remedial work.

2. Investigate pressure regulation for a small water distribution sub-zone for the

neighbourhood in the immediate vicinity of the plant.

3. Add additional booster station. Adding such a station would be the “worst case” scenario

and its implementation would require a re-evaluation of the hydraulic model.



For the purpose of this Technical Memorandum, it is assumed that resolution to the above can

be found through either Item 1or 2, or a combination thereof.

Ten States Standards recommends that emergency standby pumping equivalent to the average

day demand be provided. Technical Memorandum No. 3 estimates the maximum day/average

day factor to be 1.40; therefore, the Ten States flow recommendation for the PPWTP is

approximately 58,000 m³/d. Future fire flow demands will be evaluated by Utilities Kingston and

may add to this minimum flow.

Not accounting for any additional fire flow, if required, an approximation of the minimum standby

power required for emergency high lift pumping is 850 kW. Based on the flow conditions

presented in Technical Memorandum No. 3, low lift emergency pumping power requirement is

estimated to be approximately 150 kW. An emergency power requirement in the order of 1000

kW is therefore, required for high and low lift pumping only. This power could be provided by a

standby generator set or by engine driven pumps. This requirement will be reviewed further

during design.

. 2 Pump Configuration Options

HLP No. 1 through HLP No. 3 does not provide sufficient head to practically meet the 90 m

hydraulic head associated with the projected 2026 demands. Given the age of these pumps it is

recommended that they be replaced.

Various pump styles were reviewed including vertical turbine, horizontal split case and dry pit

arrangements. Pump styles can produce similar pumping efficiencies; however, horizontal split

case pumps located over a wetwell exhibit the greatest sensitivity to NPSH requirements.

Provided that pump selections are property made, taking into account the potential liquid level

variations and its effect on the suction characteristics of the pump, horizontal split case

arrangements are a viable option. Since the pump portion of a vertical turbine pump is

submerged, it has inherently better NPSH characteristics. Dry pit installations have the potential

to be more costly due to the more elaborate wetwell construction requirement, particularly where

rock excavation is required, as is the case at this site. There also is a potential risk of pump

flooding with dry pit installations. Either horizontal split case located above the wetwell or vertical

turbine pumps are recommended. For the purpose of the memo and because this type of pump

is used almost exclusively at this site, vertical turbines were reviewed further.



Configuration Option No.1

This option would reuse the two larger high lift pumps and provide three new units. Because of

the higher pressures, the existing pumps nominal rating will be reduced from 27,254 m³/d to

19,872m³ /d as the distribution pressure increases. Refer to Appendix 4 for possible pumping

curves. The advantage of this option is that all pumps would be similar in size and capacity.

This option will also have the lowest capital cost relative to the other options. The main

disadvantage is that the firm capacity is lower than the target flow rate, although only marginally.

This option also provides the advantage that one of the existing pumps is equipped with auxiliary

diesel drive.

Table 2 - Pump Configuration Option No. 1

Pump Nominal Capacity (m3/d)

Total Dynamic Head (TDH) (m)

New/Existing

HLP No. 1 19,872 90 New

HLP No. 2 19,872 90 New

HLP No. 3 19,872 90 New

HLP No. 4 19,872 90 Existing

HLP No. 5 19,872 90 Existing

Total Capacity (m3/d) 99,360

Firm Capacity (m3/d) 79,488

Standby Capacity (m3/d) 3 pumps required

Three New Pumps $230,000

Dual Electric-Diesel Drive for two pumps

$530,000

Estimated Piping Costs $170,000

Note: Piping costs are based on a possible HLPS General Arrangement included in Appendix 6. Configuration Option No.2

This option would have five new pumps; two similar smaller pumps and three similar larger

pumps. This option provides excess flow capacity; both total and firm, and would provide better

turndown during low flow conditions.





Total Dynamic Head (TDH) (m)

New/Existing

HLP No. 1 13,622 90 New

HLP No. 2 13,622 90 New

HLP No. 3 28,080 90 New

HLP No. 4 28,080 90 New

HLP No. 5 28,080 90 New

Total Capacity (m3/d) 111,484

Firm Capacity (m3/d) 83,404

Standby Capacity (m3/d) 3 pumps required

Five New Pumps $475,000

Dual Electric-Diesel Drive for Pumps No. 3, 4, & 5

$950,000

Estimated Piping Costs $185,000

Note: Piping costs are based on a possible HLPS General Arrangement included in Appendix 6 Configuration Option No.3

This option would have a staged transition that could delay the purchase of some of the new

pumps. All existing pumps would remain, along with the addition of two new pumps, located in a

new pumping station. This option takes advantage of the fact that the future pump operating

point considered in the first two options will not instantaneously occur. Table 3 below illustrates

the pumping capacities of the existing pumps de-rated to the proposed flow and head

characteristics forecasted for 2016. Additional pumps would then gradually be added at a certain

time between 2016 and 2026; the new pumping station would then have a set of five new pumps

with a performance similar to option No. 2 above. Pumps 6 and 7 are identical to pumps 1 and 2

of option No. 2, simply operating at a different point along its curve. When the existing pumps

are decommissioned in 2016, Table 3 would look identical to Table 2. The major benefit with this

option is that it makes better use of the existing pumps for the times when they still can deliver

the required discharge pressure.





Total Dynamic Head (TDH) (m)*

New/Existing

HLP No. 1E 7,600 80 Existing





HLP No. 6 20,700 80 New

HLP No. 7 20,700 80 New

Total Capacity 2016 (m3/d) 116,520

Total Capacity 2026 (m3/d) 111,484

Firm Capacity 2016 (m3/d) 108,920

Firm Capacity 2026 (m3/d) 83,404

Standby Capacity (m3/d) 3 pumps required (2026)

Basic Pump Costs $155,000 for two new pumps, plus $320,000 for three new pumps in the intermediate future.

Pump c/w Dual Electric-Diesel Drive

$ 320,000 for one large pump in tandem with existing Pumps No. 3 and 5, which have a dual drive.

Piping $160,000

*Estimated Discharge Pressure for 2016. Note: Piping costs are based on a possible HLPS General Arrangement included in Appendix 6.

The high-lift pumping options presented are based on constant speed pumping controlled by the

Princess Street elevated water tower. If this reservoir is out of service, a pressure regulating

valve may be required to recirculate excess pump output back to the reservoir or HLPS. This

approach is similar to the existing control philosophy. A range of flows and discharge heads are

projected for the 2006 to 2026 demands. Not only does the demand and discharge requirement

increase over the life of the WTP, but the range of minimum overnight to peak demand

conditions must be satisfied. Typically, the latter is achieved with a combination of pumping and

storage capacity. For the PPWTP, constant speed pumping combinations are proposed.

Advantages include simplicity, reduced maintenance costs, increased reliability, and reduced

capital costs. With distribution systems that include elevated storage, variable speed drives



(VSD’s) offer limited or no advantage. VSD are more complex and also represent a two to three

percent electrical efficiency loss. Optimum selection of constant speed HLP’s can provide

relatively high hydraulic efficiencies through the operating range. Additionally, scheduling major

pump overhauls and/or inspections provides an opportunity to evaluate pump performance and

modify pump impellers to provide optimum performance. On this basis, pumps should be

selected to allow for moderate increases and decreases in impeller size.

.3 High Lift Pumping Station Location Options

Evaluation of the HLPS location options must consider constructability, expandability, impact on

operations, hydraulics and initial costs. The High Lift Pumping Station operates today without

significant problems; however, with the projected 2026 demands, the wetwell performance would

be questionable. According to the Hydraulic Institute Wetwell Design Guidelines the wetwell is

sized marginally too small to properly handle the anticipated flow; therefore, improvement

methods would likely be required. The pumping station is surrounded on three sides by buried

process piping and a chlorine contact tank on its fourth side, making future expansion difficult.

As was identified in Technical Memorandum No. 2, a major shortcoming of the Water Plant is

that there is only one discharge connection to the water distribution network. Given existing

constraints, adding a second discharge watermain from the existing HLPS would be a difficult

undertaking. Also, in the event that the pumping station is retained to handle the 20 year

projected max flow rate of 80,000 m³/day, a transient response study is recommended to assess

the impact of liquid in transit if all pumps operating at the max condition were to shut down in

unison. As a result, it is recommended that a new, remotely located HLPS be constructed, in

accordance with Option 2. The location of the new HLPS has site wide implications extending

beyond the scope of this Tech Memo. Consequently, the HLPS location will be optimized during

design.

3.0 EXISTING HYDRAULIC RESTRICTIONS

Even under present day high flow conditions, the PPWTP conveyance network is reported to be

hydraulically stressed. A preliminary partial plant hydraulic profile was developed (Refer to

Appendix 5) to assess existing hydraulic restrictions.

.1 Low lift pumping station to the filters

This section of pipe was analyzed as part of Technical Memorandum No.3. It was recommended

that an additional 750 mm diameter pipe be installed to twin the current installation.



.2 Conveyance from the Clearwell to the Chlorine Contact Tank

The clearwells are connected to the chlorine contact tank by a 50 m long 750 mm diameter pipe.

Flow between the contact tanks is through a single 750 mm diameter valved opening. A 2100

mm long discharge weir was also added to the east-most contact tank to maintain upstream

liquid level. The projected headloss at a design flow of 80,000 m³/d is in the order of 1.33 m with

an estimated velocity of 2.0 m/s. This velocity is relatively high for a gravity line. With the

discharge weir set at its current elevation of 79.430, the liquid level would exceed the clearwell

roof slab elevation. Potential upgrade options include:

Option 1: Modify Existing Tanks

Conveyance between the contact tanks could be achieved by twinning the pipe between the

tanks; a hydraulic loss reduction of 260 mm could be realized based on the projected flow of

80,000 m³/d. Lowering the chlorine contact tank weir will subject the chlorine contact tank to

reduced retention times, which would likely lead to increased dosing rates. Further investigation

would be required to assess the impact. Lengthening the discharge weir would lower the liquid

crest height and would stabilize and reduce the fluctuations of the liquid elevation within the tank.

Potential hydraulic grade line reduction could be in the order of 200 mm based on a flow of

80,000 m³/d and a 6300 mm weir.

Option 2: Twin the Existing Header Feeding the Chlorine Contact Tank

This option addresses increasing flows and provides redundancy in the event that one line needs

maintenance. The potential reduction in the hydraulic grade line is expected to be in the order of

700 mm at a flow of 80,000 m3/d. It is recommended that the modifications to the chlorine

contact tank proposed in Option 1 also be included as part of the option to further reduce

potential hydraulic restrictions.

Option 3: Increase the Header from the Clearwell to the Chlorine Contact Tank

At a flow of 80,000 m³/d, the hydraulic grade line could be reduced by approximately 400 mm if

the header was replaced and increased from 750 mm to 900 mm. It is recommended that the

modifications to the chlorine contact tank proposed in Option 1 be also included as part of the

option to further reduce the hydraulic restrictions.

Option 2 is recommended as it provides redundancy and resolves hydraulic pinch points.

Option 1 is the most cost effective; however, the pipe velocity would be higher than

recommended design practice and there is limited latitude for future expansion. Option 3



provides no redundancy and unless the existing line from the clearwell is in poor condition, there

is no merit in removing it following the installation of the new main.

.3 Conveyance from Reservoir to HLPS

Flow from the reservoir to the HLPS is currently through a 75 m long 750 mm diameter which

runs south of the reservoirs and contact tanks pipe header to the HLPS. Based on the projected

plant flow of 80,000 m3/d, the flow velocity will be approximately 2.0 m/s, resulting in a headloss

of approximately 1 m. Headloss between the reservoir and the HLPS will reduce the effective

storage capacity of the reservoirs by 80 m3 per reservoir for each 100 mm of headloss.

Therefore, at design flows the total loss of effective storage capacity would be in the order of

1600 m³. If the header was increased to 900 mm, effective storage volume would be reduced to

approximately 500 m³. If the HLPS is relocated as recommended, then a new 900 mm main is

required between the existing reservoirs and the new HLPS.

.4 Conveyance to Distribution System

Flow from the HLPS to the City of Kingston distribution network is through a single 900 mm

reinforced concrete pressure pipe equipped with a 600 mm flow meter. At a flow of 80,000

m³/day, line velocity is acceptable at 1.46 m/s. The recommendation to relocate the HLPS will

require new discharge piping. It is suggested that one discharge header from the HLPS be

connected to the existing watermain which runs north/south along Sunny Acres Road and a

second discharge header be connected to the east/west running watermain along Front Road.

The second discharge header could be implemented with the upgrades or at a later date.

4.0 ON-SITE STORAGE

Onsite storage at the Point Pleasant Water Treatment Plant is provided by two 20x40 m below-

grade reservoirs with a total capacity of 3280 m³ each. Secondary storage including the

clearwell and the chlorine contact tank is not effectively available to meet water demand. The

clearwell size may require expansion and will depend entirely on the backwash requirements of

the adopted treatment and process technology. The chlorine contact tank is considered to be

adequate in size to accommodate the increased flows with an increase to the dosing rate.

The onsite reservoir storage capacity will require expansion to accommodate future demands. In

order to optimize the future storage capacity, a number of dynamic simulations of the distribution

model will be performed at the preliminary design stage using different demand and pumping

rate scenarios. For the purpose of this Tech Memo, Ontario Ministry of Environment (MOE)

guidelines and the Master Plan for Water Supply for the City of Kingston (Simco Engineering



Group, 2007) were used. MOE suggests that the required storage in a municipal distribution

system be comprised of fire storage, equalization storage and emergency storage. The quantity

of each storage component was tabulated in the Master Plan for Water Supply for the 2026 study

year under the assumption that the amalgamation of Kingston West and Kingston Central water

plants will not be undertaken. For the Zone 1 portion of the Kingston West distribution system,

the total MOE forecasted storage requirements are tabulated below:

Storage Description Volume Total Storage Requirement 21,256 m3

Zone 1 Total Storage Available 14,700 m3 Total Storage Deficit 6,565 m3 Total Functional/Equalization Storage Requirement

10,633 m3

Zone 1 Functional/equalization Available 5,870 m3 Zone 1 Functional/equalization Deficit 4,763 m3

The required additional volume tabulated above is approximately equal to the current reservoir

capacity. For the purpose of this Technical Memorandum, two reservoirs equal to the existing

will be used. The location of the reservoirs in relation to the overall site layout will be discussed

as part of the ESR.

5.0 CONCLUSION

Based on the foregoing, the following is a summary of the proposed recommendations:

Further study is required to review the integrity of the City’s water piping network,

primarily in the vicinity of the water treatment plant where it is reported that the discharge

pressure cannot exceed 690kPa. Theoretical discharge pressures are already

encroaching on this value and will be exceeded in years to come.

A new HLPS should be constructed north of the existing process building and located to

provide space for a complete new process train for a further expansion in the future. UK

may wish to install two new pumps in the new HLPS, designed to house up to five, while

maintaining the existing HLPS at its associated pumps. The existing HLPS could be

maintained in service until the distribution pressure approaches the existing pump

capacity. Alternatively, five new vertical turbine pumps could be installed to provide

80,000m³/d @ 90 m head.



Ten States recommends approximately 58,000 m³/d of emergency pumping. This will

require a combined low lift and high lift pumping emergency power capacity in the order

of 1000 kW, in addition to process power requirements. Further study into the City’s fire

fighting flow requirements is recommended, as this may add to the 58,000 m³/d

equipment.

Conveyance from the low lift pumping to the treatment process should be twinned, as

recommended in Technical Memorandum No. 3.

Conveyance from the clearwell to the chlorine contact tank (CCT) should be twinned and

modification work should be performed on the CCT to reduce hydraulic losses and pinch-

points. This work could be completed in advance of the formal upgrade project and

would include enlarging of the single pipe dividing the CCT’s and the single line feeding

the reservoirs. Modifications to the CCT discharge weir should also be considered to

maximize the clearwell freeboard available. A more detailed evaluation of the hydraulic

restrictions on this conveyance section is recommended as part of the design phase for

the proposed upgrades.

Two additional reservoirs similar in size to those currently in operation will be required.

A new 900 mm diameter conveyance pipe will be required between the existing/new

reservoirs and a new HLPS.

appendix c-5 treated water storage and …...this technical memorandum (tm no. 5) pertains to the...

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