Last updated Picture of a dry-installed chopper pump, model MPTK-I.
A chopper pump is a centrifugal pump which is equipped with a cutting system to facilitate chopping or maceration of solids that are present in the pumped liquid. The main advantage of this type of pump is that it prevents clogging of the pump itself and of the adjacent piping, as all the solids and stringy materials are macerated by the chopping system. Chopper pumps exist in various configurations, including submersible and dry-installed design and they are typically equipped with an electric motor to run the impeller and to provide torque for the chopping system. Due to its high solids handling capabilities, the chopper pump is often used for pumping sewage, sludge, manure slurries, and other liquids that contain large or tough solids.
The inventor of the chopper pump, Christian Ølgaard.
The chopper pump was invented in 1950 by the Danish company Landia. The pump manufacturer, Christian Ølgaard, developed a pump with a special knife system to meet the need for macerating and pumping manure in agricultural applications. Manure with high solids content, containing straw and sawdust, would clog up other types of pumps, causing unstable operation in an environment which required high reliability.
As the need for the pumping of difficult media expanded to other industries, so did the use of the chopper pump in both dry and submersible applications and in various industries, including meat, paper and food processing, as well as the automobile industry, biogas, chemical plants, municipal wastewater and prison lift stations.
Working principle
A chopper pump is operated by a drive unit (e.g. electric motor, hydraulic motor, power takeoff (PTO)), which turns the impeller and the cutting system. An open impeller design is used to successfully pass the macerated solids or thick slurry. A set of hardened steel cutters is installed externally to the pump suction in order to macerate all solids prior to entering the hydraulic parts of the pump. A chopper pump should not be confused with a grinder pump, which uses its impeller as part of the cutting mechanism. Grinder pumps are typically used for light weight sewage applications, whereas chopper pumps are used for tough solids handling applications.
The chopping system consists of a set of rotating cutters that are keyed to the shaft and work in conjunction with the stationary cutters, which are bolted to the suction plate. A system of mechanical seals are used to prevent the pumped liquid from entering the motor. The pump can either be connected to a pipe, flexible hose or lowered down a guide rail so that the pump sits on a coupling foot (aka base elbow), thereby connecting it to the discharge pipe.
Applications
Examples of applications where chopper pumps are commonly applied include:
Scum pumping at wastewater treatment plants
Sewage wet wells and lift stations; especially sewage containing wet wipes[1][2]
A submersible pump is a device which has a hermetically sealed motor close-coupled to the pump body. The whole assembly is submerged in the fluid to be pumped. The main advantage of this type of pump is that it prevents pump cavitation, a problem associated with a high elevation difference between the pump and the fluid surface. Submersible pumps push fluid to the surface, rather than jet pumps, which create a vacuum and rely upon atmospheric pressure. Submersibles use pressurized fluid from the surface to drive a hydraulic motor downhole, rather than an electric motor, and are used in heavy oil applications with heated water as the motive fluid.
Pumping stations, also called pumphouses in situations such as drilled wells and drinking water, are facilities containing pumps and equipment for pumping fluids from one place to another. They are used for a variety of infrastructure systems, such as the supply of water to canals, the drainage of low-lying land, and the removal of sewage to processing sites. A pumping station is an integral part of a pumped-storage hydroelectricity installation.
The activated sludgeprocess is a type of biological wastewater treatment process for treating sewage or industrial wastewaters using aeration and a biological floc composed of bacteria and protozoa. It uses air and microorganisms to biologically oxidize organic pollutants, producing a waste sludge containing the oxidized material.
Anaerobic digestion is a sequence of processes by which microorganisms break down biodegradable material in the absence of oxygen. The process is used for industrial or domestic purposes to manage waste or to produce fuels. Much of the fermentation used industrially to produce food and drink products, as well as home fermentation, uses anaerobic digestion.
Agricultural wastewater treatment is a farm management agenda for controlling pollution from confined animal operations and from surface runoff that may be contaminated by chemicals in fertilizer, pesticides, animal slurry, crop residues or irrigation water. Agricultural wastewater treatment is required for continuous confined animal operations like milk and egg production. It may be performed in plants using mechanized treatment units similar to those used for industrial wastewater. Where land is available for ponds, settling basins and facultative lagoons may have lower operational costs for seasonal use conditions from breeding or harvest cycles. Animal slurries are usually treated by containment in anaerobic lagoons before disposal by spray or trickle application to grassland. Constructed wetlands are sometimes used to facilitate treatment of animal wastes.
Maceration is the process of preparing foods through the softening or breaking into pieces using a liquid.
A garbage disposal unit (also known as a waste disposal unit, food waste disposer (FWD), in-sink macerator, garbage disposer, or garburator) is a device, usually electrically powered, installed under a kitchen sink between the sink's drain and the trap. The device shreds food waste into pieces small enough—generally less than 2 mm (0.079 in) in diameter—to pass through plumbing.
Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric motor. They are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing radially outward into a diffuser or volute chamber (casing), from which it exits.
A grinder pump is a wastewater conveyance device. Waste from water-using household appliances flows through the home’s pipes into the grinder pump’s holding tank. Once the wastewater inside the tank reaches a specific level, the pump will turn on, grind the waste into a fine slurry, and pump it to the central sewer system or septic tank.
Sewage sludge treatment describes the processes used to manage and dispose of sewage sludge produced during sewage treatment. Sludge treatment is focused on reducing sludge weight and volume to reduce transportation and disposal costs, and on reducing potential health risks of disposal options. Water removal is the primary means of weight and volume reduction, while pathogen destruction is frequently accomplished through heating during thermophilic digestion, composting, or incineration. The choice of a sludge treatment method depends on the volume of sludge generated, and comparison of treatment costs required for available disposal options. Air-drying and composting may be attractive to rural communities, while limited land availability may make aerobic digestion and mechanical dewatering preferable for cities, and economies of scale may encourage energy recovery alternatives in metropolitan areas.
The following is a partial list of types of anaerobic digesters. These processes and systems harness anaerobic digestion for purposes such as treatment of biowaste, animal manure, sewage and biogas generation. Anaerobic digesters can be categorized according to several criteria: by whether the biomass is fixed to a surface or can mix freely with the reactor liquid ; by the organic loading rate ; by centralized plants and decentralized plants. Most anaerobic digesters worldwide are built based on wet-type anaerobic digestion, wherein biomass and water are mixed in equal amounts to form a slurry in which the content of total solids (TS) is about 10-15%. While this type is suitable for most regions, it becomes a challenge in large plants where it necessitates the use of large quantities of water every day, often in water-scare areas. Solid-state type digesters, as opposed to the wet-type digesters, reduces the need to dilute the biomass before using it for digestion. solid-state type digesters can handle dry, stackable biomass with a high percentage of solids, and consists of gas-tight chambers called fermenter boxes working in batch-mode that are periodically loaded and unloaded with solid biomass and manure. The widely used UASB reactor, for example, is a suspended-growth high-rate digester, with its biomass clumped into granules that will settle relatively easily and with typical loading rates in the range 5-10 kgCOD/m3/d.
Small-scale sewage pumping is normally done by a submersible pump.
Maceration, in sewage treatment, is the use of a machine that reduces solids to small pieces in order to deal with rags and other solid waste. Macerating toilets use a grinding or blending mechanism to reduce human waste to a slurry, which can then be moved by pumping. This is useful when, for example, water pressure is low or one wishes to install a toilet below the sewer drain pipe.
A vacuum truck, vacuum tanker, vactor truck, vactor, vac-con truck, vac-con is a tank truck that has a pump and a tank. The pump is designed to pneumatically suck liquids, sludges, slurries, or the like from a location into the tank of the truck. The objective is to enable transport of the liquid material via road to another location. Vacuum trucks transport the collected material to a treatment or disposal site, for example a sewage treatment plant.
A submersible mixer is a mechanical device that is used to mix sludge tanks and other liquid volumes. Submersible mixers are often used in sewage treatment plants to keep solids in suspension in the various process tanks and/or sludge holding tanks.
Jet aerators are applied across a wide range of water, wastewater and biosolids treatment applications. Their primary purpose is to transfer oxygen to the liquid or sludge. A Jet aerator works through aspirating technology by simultaneously introducing large volumes of high kinetic energy liquid and air through one or more jet nozzles. The high velocity liquid exits the inner, primary jet and rapidly mixes with the incoming air in the outer jet. This intense mixing and high degree of turbulence in the gas/liquid cloud travels outward from the jet along the basin floor prior to the vertical rise of the gas bubble column to the liquid surface.
Effluent sewer systems, also called septic tank effluent gravity (STEG), solids-free sewer (SFS), or septic tank effluent drainage (STED) systems, have septic tanks that collect sewage from residences and businesses, and the liquid fraction of sewage that comes out of the tank is conveyed to a downstream receiving body such as either a centralized sewage treatment plant or a distributed treatment system for further treatment or disposal away from the community generating the sewage. Most of the solids are removed by the interceptor tanks, so the treatment plant can be much smaller than a typical plant and any pumping for the supernatant can be simpler without grinders.
A slurry pump is a type of pump designed for pumping liquid containing solid particles. Slurry pumps changes in design and construction to adjust to multiple type of slurry which varies in concentration of solids, size of solid particles, shape of solid particles, and composition of solution. Slurry pump are more robust than liquid pumps; they have added sacrificial material and replaceable wear parts to withstand wear due to abrasion.
High-density solids pumps are hydrostatically operating machines which displace the medium being pumped and thus create a flow.
Sludge is a semi-solid slurry that can be produced from a range of industrial processes, from water treatment, wastewater treatment or on-site sanitation systems. For example, it can be produced as a settled suspension obtained from conventional drinking water treatment, as sewage sludge from wastewater treatment processes or as fecal sludge from pit latrines and septic tanks. The term is also sometimes used as a generic term for solids separated from suspension in a liquid; this soupy material usually contains significant quantities of interstitial water. Sludge can consist of a variety of particles, such as animal manure.
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