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Figure 2: Odor Control System in Service

Neutralizing Noxious

Odors at Singapore’s Ulu

Pandan Sewage Treatment






Wastewater Municipal

Ulu Pandan Sewage Treatment Works (STW)

Ammonia, Hydrogen sulfide, Sodium hydroxide, Sodium

SUMP-GARD Thermoplastic Vertical Pump



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Reprinted from Water Engineering & Management

Water & Waste Digest

By Larry Lewis and Ken Galardi, P.E.


Three significant reputations for innovative, reliable solutions to

environmental problems came together as the Singapore Ministry of the

Environment (ENV) planned for expansion and upgrading of its water

and wastewater treatment facilities at Ulu Pandan Sewage Treatment

Works (STW).


First and foremost was the ENV's Mission Statement that Singaporeans

were to have "a clean living environment and enjoy a high standard of

environmental public health to protect against the spread of

communicable disease." This was to be accomplished through the use

of first-rate infrastructure for waste disposal, implementation of

pollution control measures and maintenance of high public health



As part of their overall environmental program, ENV turned to the

consortium of Mitsubishi International, IHI Industries and Jurong

Engineering Limited to upgrade the odor control systems at the Ulu

Pandan STW. The consortium selected Camp Dresser & McKee, Inc., as

the overall project designer and USFilter/RJ Environmental Products,

San Diego, Calif., as the odor control system supplier.


USFilter selected Vanton Pump & Equipment Corp., Hillside, N.J., a

manufacturer of thermoplastic fluid handling equipment, to provide the

specialized nonmetallic pumps required to handle the aggressive fluids

needed to neutralize the noxious emissions.


Hydrogen sulfide, ammonia or other organic compounds typically cause

the generation of odors from municipal processing operations.

Treatment of these odors at Ulu Pandan STW was accomplished

through a large centralized odor control facility incorporating 17 process

"trains," each consisting of several packed tower scrubbers in series,

followed by a dual bed activated carbon absorber. Each scrubber was

equipped with duty and standby liquid recirculation pumps sized to

maintain the proper degree of liquid-to-gas contact in the scrubber. A

total of 76 recirculation pumps was used. Thermoplastic pumps and

fluid handling piping were selected because of their chemical resistance

to the acid, caustic and bleach used in the scrubber systems, and their

proven reliability in similar applications.


Figure 1 illustrates a typical odor control system installed in the Ulu

Pandan STW. These systems were field-assembled and tested to

assure the required pH control, reduction of emissions and other

performance guarantees. A critical aspect of these systems is their

ability to handle the corrosive chemicals required for the neutralization

process and the dependable recirculation of these neutralizing

chemicals, particularly sodium hypochlorite (NaOCI) and sodium

hydroxide (NaOH). Figure 2 is a close-up of one of these systems in

operation, and Figure 3 shows a group of five such systems in the Odor

Treatment Building of the STW facility.


To provide for the dependable continuous circulation of these

neutralizing chemicals, heavy-duty vertical centrifugal pumps with all

fluid contact components made of solid, homogeneous polypropylene

were specified. This thermoplastic material is inert to the chemicals and

the pumps are rated for flows to 250 gpm (95 L/m) against a 45 foot (14

m) head over a broad temperature range. Seventy-six of these pumps

were required for the 38 packaged odor control systems at this site.

Figure 4 shows a group of these pumps ready for shipment after being

tested for performance against the specific conditions of service.

In explaining the reason for the specific pump design, engineers

emphasized the following significant specifications.


• The design should limit fluid contact to nonmetallic materials.

• The stainless steel shaft should be completely encased in

polypropylene so that no metal would contact the fluid.

• The cover plate over the fluid tank area should be supplied in the same

material as the pump.

• The immersed bearings should be nonmetallic and consist of ceramic

bearings running against Vanite outer bearings.

• The impeller should be solid polypropylene molded around a stainless

steel dynamically balanced insert, keyed to press fit into the shaft for

increased stability.

• The pump casings were to be designed for centerline discharge and

configured to accommodate larger sized impellers in order to provide

increased flows at lower power input. They were to be solid,

thermoplastic molded components, not metal components with applied



A schematic view of the pump design is show in Figure 5.


The Ulu Pandan STW Odor Treatment Building has been fully on line

since July 2000, providing efficient and reliable odor control to protect

plant personnel, neighbors and the environment.

Figure 3. This compact packed tower

scrubbing system relies on two very

different thermoplastic pumps: a

flexible liner peristaltic type rotary

pump to meter 50% NaOH on demand to the

vertical in-tank circulating pump, which

provides a continuous flow of 5% NaOH

scrubbing fluid to the tower.

Figure 3: Odor Control Systems at the

Odor Treatment Building

Figure 4: Centrifugal Pumps Ready for


Copyright 2016 - Vanton Pumps (Europe) Ltd - All rights reserved

About Us

In the 1950, Vanton developed a revolutionary all-plastic pump for use in conjunction with the first heart-lung device. The design limited fluid contact to only two non-metallic parts: a plastic body block and a flexible liner. This was the birth of our Flex-I-Liner rotary pump. Its self-priming sealless design made it an industry standard for the handling of corrosive, abrasive and viscous fluids as well as those that must be transferred without contaminating the product. Vanton now offers the most comprehensive line of thermoplastic pumps in the industry.



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