Urban sewage systems

Service Specifications for Urban Sewer Systems

Urban sewer systems require precise construction solutions with minimal surface impact, especially in established areas or those with a high density of utilities. Trenchless technologies allow for the safe installation of collectors, service connections, and deep pipelines with precise geometric control. This service is defined by the following technical parameters:

• Main applications: Installation of main and secondary collectors, gravity-fed sewer lines, connections between manholes, crossings under urban infrastructure, and renovation of existing networks without the need for extensive trenching.

• Construction methods used: Remote-controlled microtunneling, pipe jacking, and, in some cases, accessible tunnels or service galleries for large diameters. The choice depends on depth, geotechnical conditions, alignment, and urban restrictions.

• Pipe diameters and types: Reinforced concrete pipes are commonly used for main sewer lines, along with steel, vitrified clay, or other materials, depending on the municipality’s hydraulic and structural requirements and regulations.

• Soil conditions and water table: Suitable for cohesive, mixed, and stabilized granular soils. In areas with groundwater, pressurized shields (EPB or slurry) are used to ensure stability and prevent surface movement.

• Slope and Alignment Control: Urban sewer lines require specific gradients to ensure gravity flow. Laser or gyroscopic guidance allows the elevation and axis of the sewer line to be maintained within strict tolerances.

• Track lengths and geometries: Short and medium-length underpasses beneath streets, avenues, or congested service areas. When required by the design, sections with gentle curves in plan or elevation may be constructed.

• Civil works requirements: Manholes and receiving chambers adapted to the diameter and depth of the sewer, access points for machinery, a sludge treatment plant, and space for pipe handling—all while minimizing disruption to traffic and urban life.

• Compatibility with existing networks: Trenchless technologies help avoid interference with drinking water, gas, electricity, telecommunications, and underground infrastructure, thereby reducing operational risks and downtime.

• Quality control and safety: Monitoring of thrust, torque, debris removal, face pressure, and alignment. Final verification through CCTV inspection, leak tests, and as-built documentation of the completed sewer.