Pumps are not exactly the sexiest product in any water treatment catalogue. Nevertheless, they are critical in a water treatment process. They are used to administer water treatment chemicals, to move treated water from one point to another and to supply the necessary added pressure and compressed air.
Customers can find many types of pumps on the market. Dowdens Pumping & Water Treatment, for instance, offers a wide range of water treatment and pumping solutions that cater to industrial, commercial, domestic, mining and agricultural industries. This article walks you through the water treatment process and essential things to consider when selecting a pump.
Understanding the Methods and Pumps to Treat or Disinfect Water
The goal of a water treatment system is to supply quality, potable water, safe for drinking or which doesn’t pose any threat to the environment (effluent). Water treatment to generate potable water from surface water usually comprises chemical and physical processes to eliminate hazardous elements from the water and to inactivate or kill microorganisms and viruses which may cause diseases.
Physical removal can be done through flocculation, flash mixing, sedimentation basins, membranes or sand filters. In water and wastewater treatment plants, experts recommend using metering pumps for disinfection.
Disinfection is typically one of the final procedures before the water is discharged to the distribution system or discharge of the effluent. This final process makes sure that any pathogenic microorganisms are significantly reduced, and the water is safe for consumption or release to the environment. Moreover, final processes can include dechlorination and reaeration in wastewater treatment.
Common disinfection methods include the application of chlorine, ozone or sodium hypochlorite. Some water treatment companies, such as Dowdens Pumping & Water Treatment, also offer several types of ultraviolet disinfection. The effectiveness of the disinfection process relies on the water’s state or effluent being treated, the disinfection method used, the dosage of the disinfectant and other environmental elements.
Materials are carefully selected to ensure compatibility with the pumped fluid for corrosion resistance. Every chemical feed system may vary, depending on; the type of the chemical pumped, its concentration and required feed rate. Low feed rates will need metering or diaphragm-type pumps. Metering units let a specific dose of the chemical enter the receiving stream.
Choosing the right metering pump essentially depends on the necessary rate of chemical injection. Big diluted feed streams or larger feed rates can utilise centrifugal pumps to provide chemicals.
Things to Consider While Choosing a Pump for Water and Wastewater Treatment
Water treatment plants have plenty of systems with different pumping requirements. Some pumping features which are vital for different procedures include the following:
- Capacity to pump solids
- Ability to handle high to low and different viscosity
- Sealless pumping
- Repeatability of flow
The pump selection process also reviews the following:
- The process application, which includes fluid characteristics
- The system hydraulics, which includes operating envelope
- The pump selection and proper controls to satisfy the operating envelope and process application
- The material selection to make sure the operation is reliable
A final treatment phase called the filter backwash is a tertiary treatment process to enhance the quality of effluent before it is released into the environment. During this process, an effluent filter is utilised to eliminate most of the remaining wastewater’s suspended particles. Multimedia filters need a backwash water supply as well as a backwash discharge system.
Several types of rotodynamic pumps are appropriate for the process based on the clean water and operating states, including the horizontal split case, horizontal end suction, vertical turbine and submersible pumps.
The recommended construction materials include the following:
- Ductile iron for the casing
- Nickel aluminium bronze, aluminium bronze or 316 stainless steel for the impeller
- Stainless steel for the shaft
- Packing or mechanical seal
Water and wastewater treatment makes water safe for consumption and release to the environment. Choosing the right pump for water treatment ensures the effective production of quality water.