Modern control systems make pulsed airlift units better than conventional progressive cavity pumps for desludging of settlement tanks. Performance and reliability are two of the benefits of Te-Tech’s te-sewpas™ pulsed airlift system, although the principle of airlift pumping is not new, its advantages have been seen with over a dozen works since it was first installed at Southern Water’s Tangmere STW https://www.te-tech.co.uk/case-studies/tangmere-stw-te-sewpas?preview=5doz6m1y in 2019.
In the te-sewpas™, a blower generates pressurised air which is fed, via a solenoid valve, as intermittent slugs into the bottom of a pipe full of sludge. The air rises because of its buoyancy and carries a slug of sludge with it to discharge at the top of the pipe. This gentle lifting action imparts minimal shear to the sludge, minimising floc break up and preserving dewaterability. Unlike other types of pumps, there is no suction so rat-holing is eliminated. The system is equally at home transferring primary and secondary sewage sludges and it is fully automatic with high reliability making it suitable for unmanned works.
The new generation of te-sewpas™ is a completely self-contained unit with a PLC based control system that can operate either as part of a Distributed Control System or as a stand-alone unit and duration and recovery times are variable to optimise desludging operations.
Based on a typical desludging programme of four times per day, the unit will reduce power costs by about 25% and give a similar saving in maintenance expenses by comparison with progressive cavity pumps. Cost effective te-sewpas™ is the first choice for new builds and can be easily retrofitted to replace existing pumped desludging systems, providing significant capital and operational cost savings.