Lastly, manhole castings on sewers must be looked at. Perforated covers for sanitary sewers should be replaced with solid top covers. Casting which are in depressions at grade should be raised to divert surface water away. For most trenchless technology work, it is necessary to bypass flow around the sewer that is being rehabilitated. Normally, the Contractor accomplishes bypass pumping through the use of portable pumps and pipe or hose.
Flow is intercepted and pumped to an adjacent or downstream manhole.
In highly congested areas, one of the most difficult aspects of any utility work is maintaining surface traffic. In urban areas it may be necessary to develop detail plans for how surface traffic can be routed around the work areas. Trenchless technology also has applications in the water and gas industry. Additional technologies available include pipe jacking, pipe bursting and directional drilling. Pipe bursting is a technique where a pneumatic hammer is pulled through an existing pipe.