A drainage pump is generally used to remove accumulated water from areas such as basements, construction sites, stormwater collection areas, utility spaces and other locations where water needs to be transferred or removed.
Depending on the application, drainage water may contain sand, silt and relatively small suspended particles.
Typical drainage applications include:
- Basement water removal
- Stormwater drainage
- Construction-site drainage
- Floodwater removal
- Utility-area drainage
- General water transfer
- Low-solids industrial water removal
Flow Chem's submersible drainage/dewatering pump range is positioned for construction sites, basement dewatering, stormwater management, flood relief and relatively clean water with moderate solids. The current range includes models handling solids up to 60 mm, with capacities up to 130 m³/hr and heads up to 39 metres.
What Is a Dewatering Pump?
A dewatering pump is used to remove unwanted or accumulated water from a specific area so that construction, mining, excavation, industrial or infrastructure work can continue.
The term dewatering is commonly associated with applications such as:
- Construction excavation
- Foundation pits
- Mining operations
- Tunnels
- Quarries
- Waterlogged areas
- Industrial pits and sumps
- Flood-control operations
In many cases, a dewatering pump is a submersible pump designed to operate directly in the water being removed.
The distinction is therefore often more about the application and water conditions than a completely different pump technology. Flow Chem itself notes that drainage and dewatering pumps are often the same type of submersible pump, with the terminology changing according to the application.
Drainage Pump vs Dewatering Pump
| Parameter | Drainage Pump | Dewatering Pump |
|---|---|---|
| Typical purpose | Remove accumulated water | Remove water from work or operating areas |
| Common locations | Basements, stormwater areas, buildings | Construction sites, mines, excavations |
| Water condition | Clean to moderately dirty water | May contain sand, silt and suspended solids |
| Solids handling | Depends on model | Depends on application and pump design |
| Operating environment | Building and drainage systems | Construction, mining and industrial sites |
| Installation | Often installed in sumps or collection areas | Often installed directly in pits, excavations or sumps |
The final pump should always be selected based on actual site conditions rather than the terminology used for the application.
What Is the Main Difference Between Drainage and Dewatering?
The main difference is usually the application context.
Drainage generally refers to removing water from an area or system, such as stormwater or basement water.
Dewatering generally refers to deliberately lowering or removing water from an excavation, construction area, mine, tunnel, pit or industrial location so that work or operations can proceed.
However, the same submersible pump may potentially be used for both applications if its hydraulic capacity and solids-handling capability match the actual conditions.
1. Consider the Type of Water
Before selecting a pump, identify exactly what liquid will be pumped.
Ask:
- Is the water relatively clean?
- Does it contain sand?
- Is there silt or mud?
- Are there larger solids?
- Is the water contaminated?
- Does it contain sewage or sludge?
- Is it chemically aggressive?
A drainage pump designed for relatively clean water should not automatically be used for heavy sewage or dense slurry.
Flow Chem's product range separates drainage applications from sewage, wastewater and slurry applications, allowing pump selection to be matched to the liquid and solids characteristics.
2. Check the Required Flow Rate
Flow rate determines how quickly the pump can remove water.
It is commonly specified in m³/hr or litres per second.
When calculating the required flow, consider:
- Volume of water entering the area
- Required pumping time
- Size of the excavation or sump
- Rainfall or groundwater inflow
- Number of pumps operating
- Required standby capacity
A pump that cannot keep up with incoming water may allow the water level to continue rising even when the pump is operating continuously.
3. Calculate the Required Head
Flow alone is not enough to select a pump.
The pump must also generate sufficient head to move water from the collection point to the discharge location.
Total head can include:
- Vertical lifting height
- Pipeline friction
- Pipe fittings
- Valves
- Discharge elevation
- Required outlet pressure
For construction and mining applications, the vertical distance can be significant, making accurate head calculations particularly important.
4. Consider Solids Handling
Drainage and dewatering water is not always clean.
Construction and mining water may contain:
- Sand
- Silt
- Mud
- Small stones
- Concrete-related particles
- Mineral solids
The pump should have an appropriate solids-handling capability for the actual water condition.
Flow Chem's drainage/dewatering range is specified to handle solids up to 60 mm for applicable models.
5. When a Drainage Pump Is the Right Choice
A drainage pump may be appropriate when the application involves relatively clean or moderately contaminated water without heavy sludge or dense slurry.
Examples include:
- Basement drainage
- Rainwater removal
- Stormwater pumping
- Construction-site water removal
- Floodwater pumping
- Utility-area drainage
Flow Chem identifies these types of applications for its submersible drainage/dewatering pumps.
6. When You Need a Sewage or Sludge Pump Instead
Not every dirty-water application should be handled by a drainage pump.
If the liquid contains significant sewage, sludge, organic solids or larger suspended particles, a dedicated sewage/sludge pump may be more appropriate.
Flow Chem's sewage and sludge pumps are designed for applications involving raw sewage, sludge and wastewater containing solids and fibrous material, with solid handling up to 60 mm depending on the model.
Typical applications include:
- STP pumping
- Septic tank pumping
- Industrial wastewater
- Manhole sewer pumping
- Sludge handling
- Industrial effluent with high solids
7. When You Need a Slurry Pump
Heavy slurry presents a different pumping challenge.
Mining and industrial slurry may contain high concentrations of abrasive solids that settle rapidly at the bottom of a sump.
In these applications, an agitator slurry pump may be more appropriate because it can help re-suspend settled solids before pumping.
Flow Chem's submersible agitator slurry pumps are designed for settled solids, heavy slurry, STP desludging, ETP sludge handling, mining slurry and industrial sumps.
8. Consider the Pump's Operating Environment
The physical environment can significantly affect pump selection.
Consider:
- Water depth
- Sump depth
- Temperature
- Available electrical supply
- Operating hours
- Frequency of pump starts
- Accessibility for maintenance
- Presence of abrasive particles
Construction and mining sites can expose pumps to demanding conditions, so the pump should be selected for the expected duty rather than simply the required flow.
9. Consider Continuous vs Intermittent Operation
Some dewatering applications operate only during certain stages of a project, while others may require continuous pumping.
Before selecting the pump, determine:
- Expected operating hours per day
- Continuous or intermittent duty
- Number of starts per hour
- Expected project duration
- Standby pump requirements
Flow Chem's drainage/dewatering range includes 2-pole and 4-pole configurations, while its sewage and sludge range includes continuous-duty models for demanding applications.
10. Consider Pump Construction and Sealing
Submersible pumps operate directly in the pumped liquid, making sealing an important consideration.
Depending on the application, pump construction may need to withstand:
- Continuous submergence
- Abrasive particles
- Dirty water
- Frequent starts and stops
- Long operating periods
Flow Chem's drainage/dewatering pumps use cast-iron construction and double mechanical seals, while its sewage/sludge pumps use cast-iron construction with double mechanical seals and oil chambers.
Drainage Pump vs Dewatering Pump: Application Examples
| Application | Typical Pump Category to Evaluate |
|---|---|
| Basement water removal | Drainage pump |
| Stormwater removal | Drainage pump |
| Construction excavation | Dewatering/drainage pump |
| Foundation pit | Dewatering pump |
| Mine water with low solids | Drainage/dewatering pump |
| Mine water with settled solids | Agitator slurry pump |
| Raw sewage | Sewage/sludge pump |
| Heavy industrial sludge | Sewage/sludge or slurry pump |
| Fibrous wastewater | Cutter pump |
The actual selection should be confirmed using the liquid characteristics, flow, head, solids and installation conditions.
Common Mistakes When Choosing a Dewatering Pump
Choosing Only by Horsepower
Motor horsepower alone does not tell you whether the pump will deliver the required flow at the required head.
Ignoring Solids
Water from construction sites and mines can contain significant solids. Selecting a pump without checking solids size can lead to blockage or excessive wear.
Underestimating Head
A pump may have sufficient capacity on paper but fail to deliver the required discharge flow if the actual system head is higher than expected.
Using a Drainage Pump for Heavy Sludge
Dense sludge and heavy slurry may require a dedicated sewage, sludge or agitator slurry pump instead of a standard drainage pump.
Ignoring Installation Conditions
Sump depth, discharge pipe size, cable length and access for maintenance should be considered before purchasing the pump.
How to Select the Right Flow Chem Pump
A simple application-based approach can help narrow down the appropriate Flow Chem pump category.
- Identify the liquid. Determine whether it is clean water, drainage water, wastewater, sewage, sludge or slurry.
- Determine the solids. Record the approximate solids size and concentration.
- Calculate flow. Determine how much liquid needs to be pumped per hour.
- Calculate head. Include vertical lift and pipeline losses.
- Check duty. Determine whether the pump will operate continuously or intermittently.
- Review installation. Consider sump depth, discharge piping and electrical supply.
- Select the pump category. Compare drainage, sewage, wastewater, cutter or slurry options as appropriate.
Flow Chem's current product range includes submersible drainage, sewage/sludge, wastewater, cutter and agitator slurry pumps for different liquid and solids conditions.
Why Choose an Application-Based Pump Manufacturer?
Pump selection should be based on the actual operating environment rather than a generic product description.
Flow Chem Pumps is an ISO 9001:2015 certified submersible pump manufacturer based in Gujarat, India. The company states that it has been manufacturing submersible pumps since 2002 and serves municipal, mining, construction and industrial applications.
Its product range includes drainage, dewatering, sewage/sludge, wastewater, cutter and slurry pump solutions, allowing different pump categories to be considered according to the application.
Frequently Asked Questions
What is the difference between a drainage pump and a dewatering pump?
The terms are often used interchangeably. Drainage generally refers to removing accumulated water, while dewatering commonly refers to removing water from construction, mining, excavation or industrial work areas. The appropriate pump depends on the actual water and site conditions.
Can a drainage pump be used for construction dewatering?
Yes, where the water and solids conditions are within the pump's operating range. Flow Chem positions its drainage/dewatering pumps for construction-site dewatering and general water removal applications.
Can a dewatering pump handle dirty water?
Some dewatering pumps are designed to handle water containing sand, silt and moderate solids. The required solids-handling capacity should be checked against the actual site conditions.
Which pump is suitable for sewage?
A dedicated sewage/sludge pump should be evaluated for raw sewage and high-solids wastewater. Flow Chem's sewage/sludge pumps are designed for sewage, sludge and solids-containing wastewater applications.
Which pump is suitable for mining dewatering?
The appropriate pump depends on whether the mine water is relatively clean or contains significant settled or abrasive solids. Flow Chem identifies drainage/dewatering pumps for cleaner mine water and agitator slurry pumps for applications involving settled solids.
How do I choose the correct dewatering pump?
Start with the water condition, required flow, total head, solids content, power supply, installation depth and expected operating hours. These details allow the pump category and configuration to be matched to the application.
Conclusion
The difference between a drainage pump and a dewatering pump is often more about the application than the basic pump technology. Both can involve submersible pumping, but the correct selection depends on the water condition, solids, flow, head and operating environment.
For relatively clean or moderately dirty water, a submersible drainage/dewatering pump may be appropriate. For raw sewage, heavy sludge, fibrous wastewater or settled abrasive slurry, a dedicated sewage, cutter or agitator slurry pump may be more suitable.
Flow Chem provides application-specific submersible pump solutions for drainage, dewatering, sewage, wastewater and slurry handling. For a pump recommendation, provide the required flow, head, liquid condition, solids content, pit depth and operating hours so the appropriate pump configuration can be evaluated.
Explore Flow Chem's dewatering pump range, submersible pump range, or contact Flow Chem Pumps for application-based pump selection support.