A sewage lifting unit plays an essential role in modern buildings where wastewater cannot flow by gravity to the main sewer line. It collects and pumps sewage from lower levels-Such as basements, kitchens, or underground bathrooms-Into the drainage system. While these devices are designed for smooth and closed-loop operation, many users still face a common concern: unpleasant odor coming from the unit or surrounding area.
Odor problems can affect indoor air quality, user comfort, and even hygiene standards in commercial and residential projects. Fortunately, with proper design, correct installation, and regular maintenance, odor generation can be effectively controlled. The following article explains the main causes of odor and provides practical, professional methods to prevent it.
1. Ensure Proper Sealing of the System
One of the most important factors in preventing odor is airtight sealing. A sewage lifting unit must remain fully closed during operation. Even a small leak in the lid, flange, pipe connection, or inspection port can allow foul gases to escape.
1.1 High-Quality Sealing Materials
Use tanks and lids made from materials with high sealing performance, such as:
EPDM gaskets
NBR rubber seals
Precision-molded O-rings
These materials resist corrosion and deformation, ensuring that the seal remains reliable over long periods of use.
1.2 Correct Installation Torque
Gaskets and covers must be tightened using the correct force. Under-tightening causes leakage; over-tightening may damage the sealing ring. Installers should follow the manufacturer's torque recommendations to maintain the airtight structure.
1.3 Check Seals Regularly
Over time, rubber parts may age, harden, or crack. Regular inspection-every 6 to 12 months-is recommended. If any seal is damaged, it should be replaced immediately to avoid gas leakage.
2. Maintain the Water Trap (P-Trap) Function
A water trap is a simple but essential component in odor prevention. It forms a water barrier that blocks sewer gases from flowing back into the room. If the trap does not contain enough water, odor can easily spread.
2.1 Prevent Water Evaporation
In locations with low usage, water inside the trap may evaporate. Building managers should schedule periodic flushing to retain water in the trap and maintain the barrier.
2.2 Ensure Proper Pipe Slope
Incorrect pipe slope may cause the trap to siphon, losing its water seal. Pipes must follow approved installation angles so the water level inside the trap remains stable.
2.3 Choose Anti-Siphon Traps
In high-pressure or long-pipe installations, using an anti-siphon trap helps maintain the water level and prevents air suction that can damage the water barrier.
3. Optimize the Ventilation System
A sewage lifting unit requires proper ventilation to release internal pressure and guide odor gases away from occupied spaces. Poor or incorrect ventilation can force gas back into the room.
3.1 Use a Dedicated Vent Pipe
The unit should be connected to a dedicated vent pipe that leads to the outdoor environment. Vent pipes allow air to flow freely and balance pressure during pump cycles.
3.2 Install Activated Carbon Filters
In cases where external venting is not possible, an activated carbon filter can be installed on the vent outlet. This filter absorbs odor molecules and prevents them from escaping into the room.
3.3 Keep the Vent Path Clear
Dust, grease, or debris may block the vent path, reducing airflow. Regular inspection ensures that the vent line remains open and functional.
4. Prevent the Accumulation of Solid Waste
Over time, grease, sludge, toilet paper, and other solids can stick inside the tank, piping, and pump. These materials decompose and release strong odors.
4.1 Use a System with a Smooth Inner Surface
Modern sewage lifting tanks are often made of HDPE or PP with smooth internal surfaces. This reduces adhesion and makes cleaning easier.
4.2 Avoid Grease Disposal
Kitchen wastewater containing large amounts of grease should pass through a grease trap before entering the lifting unit. Grease buildup produces strong odors and can clog the pump.
4.3 Regular Cleaning and Inspection
A cleaning cycle every 6–12 months helps remove sludge and prevent odor formation. Commercial buildings with heavy usage may require more frequent cleaning.
5. Maintain the Pump and Check for Malfunctions
A malfunctioning pump can cause water stagnation inside the tank, which leads to microbial growth and unpleasant smells.
5.1 Inspect the Float Switch
The float switch controls the pump start and stop levels. If it becomes stuck, wastewater will stay too long in the tank. Cleaning or replacing the switch ensures correct operation.
5.2 Ensure Proper Running Time
Short-cycle operation may not clear the tank completely. Technicians should check the pump settings and ensure the working cycle is adjusted correctly.
5.3 Check for Partial Blockages
Pump impellers can become obstructed by diapers, wipes, or other non-flushable items. These blockages reduce efficiency and create odor. Removing blockages promptly keeps the system clean and functional.
6. Use Disinfectants and Biological Additives
Chemical or biological additives can help reduce odor by breaking down organic material inside the tank.
6.1 Safe Cleaning Agents
Use mild disinfectants that are compatible with pump components and do not damage rubber seals. Strong or corrosive chemicals should be avoided.
6.2 Biological Enzyme Treatments
Enzyme-based cleaners can break down organic waste naturally and reduce foul odors without harming the lifting unit's materials.
6.3 Regular Treatment Cycle
A simple monthly treatment can greatly improve long-term odor control.
7. Install a High-Quality Backflow Valve
A backflow valve prevents sewage from returning into the unit or pipe system, which is one of the major causes of foul odor.
7.1 Select Certified Components
Choose valves that comply with EU or North American standards, such as EN12050 or equivalent certifications.
7.2 Inspect Valve Movement
If the valve becomes stuck or blocked, gases can flow backward. Routine inspection ensures smooth operation and prevents odor leakage.
8. Follow Correct Installation Standards
Many odor issues arise because the system was not installed correctly. The installer must follow the product manual and relevant plumbing standards.
8.1 Avoid Sharp Turns
Sharp pipe bends may trap waste, causing slow flow and odor. Smooth and gradual bends help maintain a steady discharge path.
8.2 Use Proper Pipe Diameter
Incorrect pipe size can increase pressure and cause backflow of gases. Always match the diameter to the manufacturer's recommendation.
8.3 Position the Unit in a Well-Ventilated Area
Even a fully sealed system should be placed where air circulation is good. This improves safety and reduces any minor odor buildup.