SUBMERSIBLE SUMP, SEWAGE & EFFLUENT PUMPS

This is a group of submersible pumps that are designed for duty other than water wells.

In general, these pumps are single stage with large waterways to handle solids. They are usually designed for lower heads. They are NOT suitable for applications where humans are in the water with the pump, or for flammable or corrosive liquids, or for slurries or mixtures with specific gravities higher than water. There are a bewildering variety and numerous manufacturers. It is one area where you will get what you pay for, or less if you aren't careful. There is a big jump in cost when you get to pumps with bigger than a 2" discharge. They are in the class of municipal or industrial pumps. This web site will initially concentrate on the smaller pumps although we have all sizes available on request. What we have done is collect models from different manufacturers where we feel there is good value for the price and good suitability for a given application. We are not dealing with the very low end pumps used for fish tanks and the type that can be bought in hardware chain stores for less than $100. The very low end pumps are OK for very light duty, or if initial cost is the only thing that matters. They won’t last long.

The first problem is to define the application. The list below is our basic start point for types.

Sewage lift

Storm water

Basement drainers

Septic tank effluent removal

Waterfalls & water features, fish ponds

De-watering

Condensate & boiler blowdown

Before you dig in, you must have the following information:

Which category of does your application fit into?

How many gallons per minute do you want to move?

What is the total lift including friction loss in the discharge piping?

How deep is the water where you want to put the pump?

What diameter of sump will it go in?

What voltage and phase of electricity is available.

How big are the solids in the water?

How much of the time will the pump be expected to run?

How will you control the on/off cycle of the pump?

Is it in an area where it will require an explosion proof motor?

Frequently, you will not know the answers to these questions fully, and won't need to. You will have to do the best you can, and guess according to the guidelines we give you.

The major areas that these pumps differ are:

1. Motor quality. The major factors are a continuous duty application, starting type, and bearing type.

Continuous duty means that the motor can run for more than 5 minutes without overheating. Continuous duty motors are the only type we will sell.

Starting type applies to single phase motors only. It is either shaded pole, permanent split capacitor, or capacitor start/capacitor run. Capacitor start /capacitor run has the most starting torque and is the best method but only found in larger single phase pumps. Permanent split capacitor is better than shaded pole. Shaded pole motors are also less energy efficient.

Bearings are either ball bearings or sleeve bearings. This is an important point in durability. Upper and lower ball bearings are superior. One ball bearing is next, sleeve bearings are lowest.

Built in thermal overload protection with automatic reset is an important feature. It both helps protect the motor and makes it legal by the National Electrical Code. (This is a very tricky subject, especially for larger pumps.)

2. Impeller type and solids handling capability. The basic rule is that if you have to put a screen around it, it won't last long. In all the history of pumps, nobody has ever cleaned a screen often enough. There are three types of impeller A. conventional non-clog ,B. Open trash type, 3. Vortex. 4 Grinder

A. Non-clog impellers are not non-clog, they can just pass much bigger solids than a clean water design. Typically, impellers designed for almost clean water, such as septic tank effluent can pass 3/4" solids. (Almost clean does not mean you should drink it.) Those designed for raw sewage are rated at 2" solids. Don't try it. They can however, pass the average turd. They will choke on underwear, sanitary napkins, disposable diapers, pencils, towels, socks and a surprising amount of other things that can be flushed. Stringy things such as laundry waste and condoms can wrap around the shaft.

(One of our local sewage plants found a whole motorcycle frame in their inlet pipe.)

B. Open trash type impellers are usually multi-vane with no bottom plate. They pass 3/4 to 1" solids. They can pass stringy stuff, leaves, grass, wood chips, but not big solids.

C .Vortex impellers are flat plates with vanes on them which are raised up out of the main water passages. The action is sort of like a blender. They work surprisingly well. They are capable of passing just about anything that can get in the housing. They will pass rope, socks, rags, and some towels, plus anything that either a trash or non-clog will pass. They will even pump if their is something partially blocking them.

These are a strong favorite of ours since there are far fewer plugging problems with them. There are also far less motor problems since many motor problems come from running overloaded due to plugging, or off balance due to something stuck in a vane.

The down side is they are not very efficient and do not build up high heads easily. Most of the pumps we offer will have this type impeller.

D. Grinders. These pumps have hardened steel cutting surfaces on the inlet to chop everything down to a size the pump can pass. They work if you need them. Typically, they are used where you have a small discharge pipe, usually 2" , going up a relatively high distance, more than 15 or 20'. They are much more expensive and are expensive to repair. If a steel object, such a bolt or wire, gets into them, they can be damaged quickly. They should only be used where necessary. For rough terrain, rocky areas where small discharge pipes are a big economic necessity, they are great. They generally are designed for high heads and low flows and take much bigger motors than other pumps in this class.

3. Materials of construction. The housing and impeller can be either cast iron, bronze, plastic, or stainless steel. There is little advantage between cast iron, bronze and stainless steel for these applications. Cast iron is fine unless there are unusual corrosion factors. Plastic pumps are perfectly acceptable but are less tolerant of sand wear than cast iron and plastic impellers are easier to damage or strip off the motor shaft. Plastic pumps are light and corrosion resistant. They tend to be lower end pumps but can be very cost effective.

4. Shaft seals. All small pumps have carbon/ceramic shaft seals. Larger municipal and industrial pumps may have double seals running in oil, or silicon carbide/tungsten carbide seals. This is not something to worry about in this class of pump.

 There are other differences but these are the ones to be concerned about.

 SEWAGE LIFT PUMPS

The basic function is lifting human, or animal, waste up into a disposal system. Human waste volume ranges from 50 to 100 gallons per person per day. Some typical discharges are:

Total Delivery rate     gallons/min

Shower 25 -60 gal 5 GPM

Bathtub 30 -35 gal 5 GPM

Bathroom sink 1 -2 gal 4 GPM

Toilet flush 30 -35 gal 4 GPM

Kitchen sink 5 GPM

Washing machine 30 -50 gal 5 GPM

Dishwasher 10 -20 gal 2 GPM

Water softener to 150 7 GPM

It does not take a very big pump to handle a house. If 12 people live in a house and use 100 gal/day each, that is 1200 gallons/day. A 20 gal/min pump can do that in an hour. It is hard to build a pump with waterways large enough to handle human waste without pumping at a higher rate than that. However, you have to have a sump large enough to handle a surge. Thirty seven gallons is a minimum.

Some thought must go into the amount that will flow back into the sump when the pump stops. 2" pipe holds .163 gallons/ft of length. If enough will backflow into the sump to restart the pump, you must install a check valve.

Reliability is very important with this type pump, but every pump will eventually fail, so make sure the piping is such that the pump can be removed with the sump full of shitty water. It is very hard to get local SCUBA divers to go into sewage pits, but septic tank services can pump pits out, for a price. Do not build things over the sewage sump. Make sure there is a union or compression coupling in the piping on the surface.

The minimum solids handling capacity is generally considered to be 2" solids. Do not even think about any type of screen arrangement. It will not work.

The Sump and Sewage Pump Manufacturers Assn.. of Chicago, Illinois, puts out guidelines for sizing in a booklet.

STORM WATER PUMPS

These are used to handle rainwater runoff. Storm water is even a worse solids problem than sewage because things like beer cans, spray cans, survey stakes, 2 x 4's, plastic bags, paint can lids, leaves, and even dead cats, end up in them. However, this application can be protected with grates or trash racks if done properly. Screens are harder to clean and more likely to plug up with smaller trash that the pump can pass, such as leaves. The most common applications for small pumps are truck loading docks, driveways, and parking lots.

The amount of water you need to remove depends on the area of blacktop surface you are draining and how much you are willing to let it pond up for gradual removal. You also have to consider where you are going to pump the water to and how fast it can take it. Generally, your neighbors backyard or public roads are not allowable disposal areas.

For a ten year storm you can figure .15 acre-feet of water per acre of non-absorbent surface. For a 50 year storm, figure .35 acre-feet per acre. An acre foot is 43,560 cubic feet or 325,900 gallons. A pump rated at 100 GPM will pump 144,000 gallons in a day.

These are generally low lift applications, but higher volume than domestic sewage pumps. The vortex impeller is recommended if there is no trash rack. A conventional non-clog will work if protected. No other impeller type is satisfactory.

Once again, the pump will only fail in a rain storm. It is necessary to install it in a manner that it can be removed when the sump is full of water. ( The classic brain dead installation is to put a pump in the bottom of a 20' deep concrete pipe and hard pipe it through the wall at the bottom without even a union. This was designed by a registered Civil Engineer. )

BASEMENT DRAINERS

These are used to remove seepage in buildings. This is very light duty. Usually the water is quite clean and the volume is low and the lift is about 10'. This is one area where low end pumps will give satisfactory service since they run so seldom and have such an easy job.

 SEPTIC TANK EFFLUENT PUMPS

These are used to raise liquid from the discharge end of a septic tank up to the level of the leach field. They are low volume, since the septic tank serves as a large reservoir, but tend to be higher head than sewage lift pumps. The solids content of the water is small. They are usually designed to handle a 3/4" solid. This is not hard duty, but reliability is important since you wont find out about the pump failure until you have a big mess. It is necessary to have a good idea of the elevation difference between the septic tank and the leach field. The horizontal run doesn't matter much. It only contributes to pipe friction. If you know the pipe size, material and length it can be calculated. If you don't have the information, figure an extra 2' of head if it's close, or up to 5' if it is far away with many turns. There are a class of pumps made for just this application.

WATER FALLS, WATER FEATURES, FOUNTAINS, FISH PONDS

These applications are generally relatively high volume and low head with moderate solids. It is best to plan on solids because of wind blown leaves and twigs, frogs, turtles, fish, plastic toys, plastic bags, balls. Some judgment is required, but it is foolish to figure you will not get some solids. These applications frequently require high running times and thus need the best motors. Some attention needs to be paid to correct sizing since they can run up a power bill a surprising amount. Vortex or non-clog impellers can be used. Some basic bar screen is a good idea.

Fish tanks and ponds should have a pump capable of recirculating the entire tank or pond volume in 2 hours.

Very small waterfalls, such as indoor ones, are not our area. Outdoor waterfalls can have vastly different water requirements. A rule of thumb is 50 GPM per foot of width. Water features, such as streams, take large volumes and very low lift. The friction in the return pipe is the major element and should be calculated. The flow will vary with slope, shape, width, and roughness. Just to give you some idea of requirements, a dirt ditch 2' wide running 3" deep, with a slope of 5/16" per 100' of length, would require about 90 GPM. Please don't use these numbers for multi-thousand dollar projects without getting some professional help.

Fountains depend on nozzle size, whether it is a professional smooth-bore, tapered nozzle or a plain pipe, and pressure at the nozzle. Some examples for professional nozzles are: 

For a 10' spray height For a 20' spray height

1" pipe tapered to 3/8" requires: 12 GPM at 14' (6 PSI) 18 GPM at 27' (12 PSI)

1 2" pipe taper to 5/8" requires 30 GPM at 14' 45 GPM at 27'

 Fish ponds, real ones, not household aquariums, usually have a certain number of water changes required per day and depend on the fish and the climate. The purpose can be aeration, filtration, cleaning, or temperature control. We don't know anything about fish except they taste good. It is necessary to keep the fish out of the pump for the sake of both parties. We would welcome any reader input on some rules for fish ponds since we have only provided what pumping was asked of us.

 DEWATERING PUMPS

This usually refers to removing groundwater from an excavation of some sort. The pumps are subject to periods of running dry, very long running times, severe abrasion and mechanical abuse. The solid size is usually relatively small and limited to sand, and small rocks which can be screened out. It takes a heavy duty pump.

For some shallow open cuts, a good quality, cast iron, sewage pump is an economical choice. For use in dewatering wells and bore holes, special pumps are made. They are quite expensive and for contractor use. We do have them available

 CONDENSATE AND BOILER BLOW-DOWN

This is clean water that is hot. Solids handling is not important. Most small submersible wastewater pumps have motors and seals rated at 130F. High temperature pumps are rated at 194 to 200F. These are readily available but somewhat more expensive.