Pumps We Often Use

Yes, Romtec Utilities frequently designs lift stations that have two or more pumps. In typical use, the control panel will sequentially alternate starts between each pump so that the pumps will accrue equal runtime during the life-cycle of the lift station. This practice reduces some maintenance requirements for the pumps. Additional pumps also offer a measure of redundancy, providing backup should one pump malfunction.

Yes, Romtec Utilities offers a variety of grinder pumps, cutter pumps, and chopper pumps. We can provide various types of pumps that macerate solids prior to pumping in wastewater, stormwater, and industrial water pumping applications.

Yes, Romtec Utilities includes lifting rail assemblies for any pump required. We provide complete stainless steel rail systems in any size for any size pump. These lifting rail systems can be integrated into any sump configuration, such as concrete, fiberglass, round, or rectangular. The lifting rails can also be designed for any type of manhole. Romtec Utilities will always make sure that the lifting rails proposed will meet the requirements for the mechanical and configurations elements of a package lift station.

Animal hair and grease from fryers are two examples of difficult to pump substances. Romtec Utilities has designed lift stations that needed to address these substances. Animal and pet hair is difficult because it as a tendency to clog pumps. Hair from animals does not break down easily, and it tends to wrap around moving parts. Pumps in systems with known levels of animal or pet hair should be serviced several times throughout the year. Grease will usually build up on the surface of wastewater and interfere with the level sensing devices. Grease can also build up on the walls of the sump, in the pumps, and in the system piping and valves. The best approach is to eliminate grease from the system by installing grease traps at the point of origin.

Romtec Utilities designs package lift stations with a redundant pump whenever possible. This is because there are several advantages to this type of design. The principal advantage is that if one pump goes offline then the redundant pump can kick on to handle the peak flow of the system. For example, in a duplex system (2 pumps) each pump is capable of pumping the peak flow on its own, hence the redundancy. Another strong advantage with pump redundancy is that each pump alternates between pumping cycle starts. This rotation between pump starts sustains an equal run-time between the pumps and their maintenance schedules. It also extends the life of each pump by preventing continuous operation. The final advantage of pump redundancy is handling emergency high flow scenarios. In some instances, inflow rates can suddenly surge above the peak flow, whether from inflow and infiltration or otherwise. A redundant pump can then operate with the other pump (or pumps) to handle the excess inflow rates.

One advantage is having redundancy within the system. If one pump malfunctions, there is a back-up to keep the system operational. Another advantage to having multiple pumps is the ability to cycle the operation of each pump to reduce wear and allow for maintenance to be conducted during off periods. For cost saving measures, larger pumps can sometimes be replaced with multiple smaller pumps to handle the same amount of flow. This is not always applicable but it can be a better option for the same redundancy reasons. Multiple pumps also give the system the ability to handle a wider range of flow rates in a more efficient manner. If the system sees dramatic swings in peak inflow due to seasonal weather or other reasons, then the system could run on one pump for part of the year and then run the second and/or third pump for periods of greater flow.

Surface mounted pumps have a few advantages. The main advantage is the fact that they are not under water. In industrial applications, there can be harsh materials that can quickly corrode and damage the pumps. Submersible pumps in this situation must be stainless steel, which can dramatically increase the price. Even with stainless steel pumps, it is difficult to find a model that can completely combat the corrosive nature of the conditions. Surface mounted pumps keep the motor and all components of the pumps out of these harsh conditions by pulling the water up from the bottom of the wet well through stainless steel shafts. Another advantage is that lift station operators and maintenance personnel are able to work on the pumps without entering the wet well. This drastically reduces the hazards and safety precautions that are associated with confined spaces, falls, and drowning.

Grinder pumps and chopper pumps both macerate solids before the water flows through the pump, but they accomplish the task differently. Grinder pumps grind up the solids into slurry in order to pump the liquid. Chopper pumps combine a solids handling throughlet with fixed cutting blades that chop up the solids that cannot pass through. Grinder pumps are typically used in low flow scenarios with high total dynamic head, TDH, where the peak flow rate is below 75 gpm. Chopper pumps can typically be used within the same range of flow and TDH as a solids-handling pump, i.e. 100 – 5000 gpm. Please see the following video demonstration from Vaughan of a chopper pump. http://www.youtube.com/watch?v=zhTEjFd-vxo Please see the following video demonstration from Goulds Water Technology of a grinder pump. http://www.youtube.com/watch?v=TrbcBcGww2U

One of the main disadvantages of standard solids handling pumps is that there is a nominal solids passing diameter. The pumps, depending on their size, can only pass solids that are smaller than the intake of the volute and piping. If a larger solid tries to pass, it can potentially block the pump. Another problem with solids handling pumps is that they are dependent on the force main size and its ability to pass the same solid that the pump can pass. There is a chance of clogging the pump if the pump can pass a larger solid than what the force main can handle. Solids hand pumps are also dependent on the flow rate. The size of the force main and flow rate dictate what pump will be picked in a design by determining the total dynamic head of the system. Solids handling pumps are not good in low flow, low head conditions. Often the design flow has to be higher than the peak flow to create extra head so a pump can be selected. Additionally, solids handling pumps are not good in low flow, high head conditions, and finding a pump is difficult. Lastly, not all solids handling pumps are available with an explosion proof (FM) rating. This rating can be crucial in wastewater applications if the area is designated as class 1, division 1.

Surface mounted pumps present disadvantages when designed into a lift station. The main disadvantage is that the pumps are at grade, making them visible, unprotected, and un-muffled. Depending on the location of the site, the visibility and noise the pumps create could become a big issue. If the lift station was designed to service a large subdivision, the nearby houses could be affected by the noise of the pumps and/or generator starting up and running, and the visual of a large mechanical system as part of their setting. Leaving the pumps at grade also requires some sort of protection, possibly a fence or shelter that could also be visually unattractive and is certainly an added cost. Another disadvantage is the added head to the system. The pumps are now forced to pull the water from the bottom of the wet well up to grade and then push it to the force main discharge. This must be accounted for in the design of the lift station.

A jockey pump is normally a smaller pump that fits into a lift station to handle nuisance flow or, possibly, small constant flows. Lift stations are designed to meet the peak flow that the system could see, but this can lead to a system that is way over-designed for the flow seen 99% of the time. For example, a lift station could be designed to handle all the stormwater from a housing development during a huge winter rainstorm, but for 10 months of the year the lift station only deals with runoff from sprinklers. It would be a waste to have a large pump constantly turning on and off to deal with a minimal amount of runoff, so the jockey pump takes care of these situations. This setup saves money through energy savings and maintenance costs.

A chopper pump has a sharpened edge on the impeller which acts as a chopper as solids come through the pump. The impeller is mounted against a static bar that creates a scissoring action by which the impeller chops large solids against the bar into a size that can travel through the volute and out the discharge piping. A grinder pump does not allow any solid to pass through the volute and out the discharge piping. All solids are ground into a chum before entering the volute. Grinder pumps can be much slower in processing influent, and they dramatically reduce the pipe size from the influent to the discharge.

Romtec Utilities is not affiliated with any single pump manufacturer. Romtec Utilities offers all major pump brands on our complete, site specific lift stations. If you have a specific preference or standard, Romtec Utilities will be sure to use that pump manufacturer in our design and engineering services.

Typically the type of water and the classification of the space are the main factors in deciding when to use explosion proof pumps. In the majority of wastewater applications, explosion proof pumps are preferred so that gases coming off the water cannot trigger an explosion. Industrial water applications can also require explosion proof pumps, such as with oily water, chemical water, cleaning water, and more. With clean water and most stormwater scenarios, explosion proof pumps are typically not required or necessary. The designations for a hazardous area may also require explosion proof equipment be included in a pump station. Typically, these areas will be Class I, Division I, but other designations – like zones– can have the same impact. Aside from these common situations, there are additional factors that may require the inclusion of explosion proof pumps. Romtec Utilities will help guide you in the process of selecting the appropriate pumps for any possible scenario.