The Submersible Wastewater Pump Association (SWPA) is a national trade association representing and serving the manufacturers of submersible pumps for municipal and industrial wastewater applications, the manufacturers of compo0nernt parts and accessory items for those products, and non-manufacturers who providce srevices to users of those products. Founded in 1976, the association`s primary focus is on industry guidelines, education and promotion.
Originally used in Europe, submersible wastewater pumps were first seen in the U. S. Market in the mid-1950s. They became popular in the early 1960s when a guide rail system was developed to lift pumps out of well pits for easy maintenance and repair.
Submersibles are now the dominant pump in the municipal lift station market. They offer these advantages
- low initial cost since they involve only one pit and less auxiliary equipment is required than for dry well/wet well installations;
- low operating costs;
- safe and quiet installations;
- a minimum of unsightly above-ground equipment; and, above all,
- reliable operation over a long life.
A submersible lift station includes not only the pump-motor unit, but sophisticated electrical and mechanical controls, piping and wet well with access frame and cover.
Submersible pumps are also widely used to handle suspended solids effectively and efficiently.
Submersible Wastewater Pumps
The submersible solids handling sewage pump operates under water. It is flood-proof. It is designed for single, wet-pit use. It can be removed easily for maintenance. It is efficient, quiet in operation, safe to install, and performs long and reliably.
The submersible wastewater pump is used primarily for wet-pit sewage lift stations and for industrial sump or process effluent applications. A common use for small pumps is to move effluent from tank to disposal in septic tank systems. Large and small units are used in a variety of ways in the home, farm, motel, school, marine, commercial building, industrial plant, and municipal sewage and stormwater systems.
Submersible pumps have been proven over the last half of a century, disproving those skeptics who originally asked how an electric motor-powered pump 'could run under water'. Originally developed in Europe, they are now used throughout the world to pump clear water, raw water, and wastewater. Millions are in daily use.
The submersible wastewater pump came to the U.S. about 1955. It became popular in the early 1960s, when a guide-rail system was developed to lift the pump out of the pit for repair; this ended the dirty and sometimes dangerous task of sending people into the sewage or wet pit. Growth of the submersible for wastewater pumping has since been dramatic, as an increasing number of specifiers and users learned of its advantages.
There are two classes of submersibles. One is the smaller unit, used in home and light commercial applications; they normally handle up to 2-inch spherical solids and range from 1/3 to 2 horsepower. They are commonly called 'sewage ejectors'.
Larger submersibles are discussed here. They handle 2-1/4 inch and larger solids, and have a minimum of 3-inch discharge. They are used in municipal and industrial applications, for pumping sewage and all types of industrial wastewater.
Advantage of Submersibles
Submersible wastewater pumps have a number of advantages to users.
A major one is low initial cost. In sewage pumping applications, only one pit is necessary, which reduces initial investment. There is no need, in most installations, for ventilation, lighting or other equipment, which is normal for dry pits. Flooding problems are also eliminated.
Another advantage is low operating cost. Compared to above-ground pumps, for example, submersibles are more efficient. They have the obvious hydraulic advantage of working in the water and not some distance above it. They never lose prime.
Submersibles have safety and noise reduction benefits, too, since the working installation is well below ground level. There is less chance for accidents from an exposed motor and there is a minimum of noise when the pump is operating.
There is a minimum of above-ground equipment, usually only the control box and a frame for use in attaching the hoist for removal of the pumps. There is no unsightly pump or any need for a pump house. Moreover, because wet-wells are designed so incoming wastewater scours the bottom, there is little chance of odors.
But the most striking advantage of submersibles is reliability and long life. The pump is designed to operate efficiently under water. It runs only when needed, reducing wear and power bills. Suction pipe clogging and net positive suction head (NPSH) problems are also eliminated. The water cools the motor naturally, adding to its life span. Field service is simple and sure. And submersible manufacturers report that fewer than one-half of one percent of the pumps they ship are returned for replacement.
Submersible wastewater pumps are the fastest-growing products in the fast-growing wastewater and solids handling field.
Here’s an introduction to selection and use of this fast-growing product.
Description: Submersible wastewater pumps are vertical, direct-coupled, extra-heavy duty units, which operate under water and have a solids-handling, non-clog capability. While single pumps are often installed, most applications require two pumps (called 'duplex') - to insure continued operation if one pump fails - to minimize wear on one pump and equalize it between two - and to provide extra capacity in times of extraordinary loads.
A submersible pumping system consists of the motor-pump unit together with automatic electrical controls. Controls can be simple or complex, depending on the application. The latter may consist of an entire factory-packaged station enclosed in a steel or fiberglass tank, and ready for installation and pipe-electrical hookup.
Submersibles are being specified increasingly in applications where self-priming, dry pit, straight centrifugal, vertical extended-shaft, and pneumatic ejector pumps once dominated.
Discharge Size: Depending on the impeller design, a 4-inch discharge pump will normally handle spherical solids from 2-inches to 3-inches. Each manufacturer’s literature specifies the maximum solids size, which can be handled by a particular pump.
Normal discharge sizes for larger submersibles range from 3-inch to 14-inch and larger. The pump selected should be sized to the application.
Motors: Submersible pump motors can be sized to the application. They are normally available in 850, 1150, 1750 and even 3450 designs, on 60-cycle power. Horsepower ratings range up to 100 HP or larger. Variable speed units are also available with the use of variable frequency and voltage power supplies.
Again depending on the application, motors operating on 200/208-volt, 230-volt, 460-volt, 575-volt and higher are available. Motors may be single or three-phase, as specified; single phase units are usually limited to 10 horsepower. Thus, submersibles can be tailored to job requirements.
Capabilities: Like any pumps, submersibles can also be tailored to the capacity requirements of the particular installation. A specifier can ask for a high dynamic head, or can accept a lower head and obtain a higher gallons-per-minute flow rate - or can get both a higher head and a higher flow rate by increasing the horsepower rating.
Typically, dynamic heads range from 15 to 300-feet. Flow rates range from 10 to 2,500-gpm-and larger pumps produce 10,000-gpm or more. The pump-motor unit can be tailored to installation needs.
Many larger pumps can be used in conjunction with a variable speed drive (VSD) to further fit the performance to the application.
Control panels are engineered for the particular installation. The heart of the control system for submersibles is the liquid level control, which activates and deactivates the pump(s) at specified levels within the wet-well. The simplest control system would contain an On-Off magnetic contactor and disconnect. Systems normally have three sets of controls - one for turn-off of the first pump, one for turn-on of the pump, and one for the high liquid alarm. Duplex systems usually alternate pumps on each successive cycle. Duplex systems also usually include an override control, which brings in the second pump when in-flow is unusually heavy or in case of failure of the first pump.
Control panels are installed above ground, and usually contain: (1) pump disconnects, (2) across-the-line starters with overload protection, (3) hand-off-automatic selectors, (4) elapsed time meters, and (5) alarm systems for indicating high level conditions in the wet-well. In addition, duplex systems provide for automatic sequencing and alternating of pumps. Alternation allows for equal run time and wear of the pumps.
Alarm systems vary but can be visual, audible or remote monitoring by telemetry devices or telephone lines.
The manufacturer will help determine what controls are needed for a particular application, and then manufacture the control panel to this specification. All are built to NEMA standards and in accordance with the National Electrical Code.
Wet-pit installation is a major advantage of submersible wastewater pumps, since only one pit is required. The pump is usually installed on guide-rails. If field service or replacement is needed, the pump is easily lifted to the surface. When lowered into position, the pump outlet flange automatically seats with the discharge piping. There is no need for wrenches or special tools, or for anyone to enter the pit.
Most submersibles can be serviced in the field without disturbing the piping; this represents a major cost saving to the user.
Complete package sewage lift stations are available from some manufacturers. The complete package from the tank to the pump-motor unit, guide-rails, piping and valves, all controls, etc. - is shipped ready for installation.
Access frames and covers are available from manufacturers for either wet-pit or sump allocations. They are designed so the cover can be locked safely in the open or closed position. Traffic-bearing covers are available.
SWPA’S Mission Statement
The mission of the Submersible Wastewater Pump Association (SWPA) is to enhance the global wastewater environment by informing, educating and providing leadership in the design, procurement and operation of submersible wastewater pumping systems.
SWPA’S Purposes And Objectives
To promote increased use and consumption of the products of the submersible wastewater pump industry.
To perform such functions as shall promote and provide for the welfare of the industry and engage in all lawful activities appropriate for an industry trade association, including but not limited to:
- Analyzing and discussing conditions affecting or which may affect the industry;
- Studying improved operating methods and procedures;
- Conducting education and research activities;
- Formulating or assisting in the formulation of tests and test methods for industry products; and
- Representing the industry in contacts and relations with other organizations, the government, and the public.
To cooperate with other associations and groups where necessary or desirable in carrying out the purposes and objectives of the Association.
To do any and all lawful acts and to perform and furnish any and all lawful services which may be deemed to b useful and desirable in order to effectuate any of the above purposes and objectives or to conduct any of the above activities.
SWPA's members are leaders in the field. Regular Members are manufacturers of submersible wastewater pumps for municipal and industrial applications that can efficiently handle solids. These companies represent the bulk of U. S. shipments of Non-Clog and Grinder Pumps. Component Members are manufacturers of component parts and accessory products for submersible pumps and pumping systems. They supply pump manufacturers and the aftermarket with access covers, alternators, basins, cords/cables, control components, control panels, electric motors, guide rail systems, phase converters, phase monitors, seals, valves, variable frequent drives and other components and parts. Associate Members are non-manufacturers providing services related to Industry Products and/or who provide services to users of Industry Products.
SWPA is a focal point of the industry's communications network. The association provides a forum for pooling of skills and know-how of member companies, and facilitates the exchange of information on problems and issues of common concern.
SWPA maintains a data center for the industry providing information to trade and consumer press, other business groups, users, and members.
SWPA serves submersible wastewater pump manufacturers. One of the association's goals is to increase acceptance and sales of this modern, efficient and effective product.
SWPA represents its members with numerous groups involved in the selection, installation and use of industry products -- including engineers, specifiers, users, standards officials and code authorities.
SWPA seeks to help its members by providing information on subjects of general industry interest -- including government actions, code changes and marketing trends.
SWPA is and has been a leader in the growing wastewater pump industry since its inception. The association has a distinguished history and a long list of achievements including:
The Submersible Sewage Pumping Systems Handbook, 3rd Edition (2004) is a 164-page technical volume that was developed by a task force of industry experts. This one-of-a-kind publication familiarizes and assists those responsible for designing, installing and operating lift stations using submersible solids-handling pump systems. The third edition includes additional chapters on Grinder Pumps and Pressure Sewers and Variable Speed Pumping. The SWPA Handbook was introduced to the industry in 1984 in a soft cover version. It has been published in a hard cover format since 1986. Since its introduction, over 20,000 copies have been throughout the world. The 4th Edition will be available in mid-2012, including a version in Spanish. For ordering information, contact SWPA Headquarters or click here for our technical resources on line Order Form
- The Field Start-Up and Check-Out Procedures Manual for Submersible Sewage Lift Stations (1998), is a practical, 28-page text that includes presents step-by-step procedures, based on equipment available, for putting a lift station into operation.
- SWPA's Statistical Reporting Program provides quarterly data on non-clog and grinder pump shipments by type and size and annual data on the destinations of those shipments.
- A unique Annual Industry Outlook Survey. Each Fall, SWPA conducts an Annual Survey of its members to gather information on expected industry performance for the coming year. Included are projections of Non-Clog and Grinder Pump shipments by types and sizes. The survey results are presented during the association's Annual (Fall) Meeting.
- 'The Very Versatile Submersible' is a video training program that was created to inform viewers of the advantages and multiple uses of submersible wastewater pumping equipment. This eight-minute presentation was designed for use at seminars, schools and selected meetings and discusses some of the ways this versatile machine serves specifiers and users throughout the world. click here for our technical resources on line Order Form
- The SWPA Standardized Presentation Format for Pump and Motor Characteristics. The format includes the minimum information needed by a specifier or designer to adequately evaluate using a specific submersible wastewater pump for an individual application. Information is presented in a consistent format so the designer or specifier can make an informed comparison between different brands or types of equipment. A series of standardized pump/motor definitions of the terms that the data represent in included. click here for our technical resources on line Order Form
- An Introduction to Grinder Pumps in Pressure Sewers. click here for our Power Point presentation
- A Technical Library of information along with a bibliography of current literature. Members as well as non-members are encouraged to submit materials for possible inclusion in the library.
SWPA has two general membership meetings each year. The Fall (Annual) Meeting is held each December and typically includes a technical presentation by an industry expert, a federal legislative update and other educational programming. The association's Mid-Year Meeting is held in the Summer and includes a Plant Tour, related technical seminar and other educational programming. The association's Marketing and Technical Committees meet at both the Fall and Summer Meetings and typically have full agendas. Other Committees are formed and meet as needed. In addition, the association’s Executive Committee and Baord of Directors meets between the membership meetings. Committees and subcommittees meet on an as-needed basis.
SWPA is dedicated to building the submersible wastewater pump industry. The association welcomes inquiries regarding membership benefits and services, as well as its programs and activities.
SWPA is the industry's leader in providing accurate, up-to-date technical information about submersible wastewater pumps and the component parts and accessories in lift stations using solids-handling pump systems.
Now in its third decade of service, SWPA has become the recognized spokesman for the submersible pump segment of wastewater industry and looks proudly upon its long legacy of service.
SWPA's dedicated members and staff have worked diligently, particularly in recent years, to position the association as the premier resource for technical information on submersible sewage lift station systems in North America.
The technical information created and distributed by SWPA is developed by knowledgeable specialists from the industry's leading manufacturers of submersible pumps and component parts and accessories. This information is based on a systems approach for municipal and industrial applications and is designed to meet the needs of those who are responsible for designing, installing and operating lift stations using solids-handling pump systems.
SWPA's Membership Requirements
The Association's Bylaws list membership qualifications as follows:
Section 1. Eligibility for Regular Membership. Firms, partnerships, corporations, or other types of business enterprises which are actively engaged in either (a) the manufacture and sale of or (b) the sale on substantially a nationwide basis in the United States of America of one or more industry products as defined in Section 2 hereof are eligible for Regular Membership in the Association.
Section 2. Industry Products. Industry products are defined as submersible wastewater pumps that can efficiently handle solids. Industry products may also include such other products as the Association's Board of Directors may from time to time determine are industry products.
Section 3. Eligibility for Associate Membership. Persons, firms, partnerships, corporations, or other types of business enterprises which are actively engaged in the manufacturing of parts or equipment distributed on a nationwide basis for the types of submersible wastewater pumps manufactured by the members hereof, and for systems utilizing such pumps, are eligible for Associate Membership in the Association.