Client: CEMEX
Project Value: £200K
Project Period: AUGUST 2020 TO OCTOBER 2020
The Longford methane stripping plant was designed and built by Phoenix Engineering (Phoenix) for CEMEX.
Located at the closed Longford Landfill Site near Slough.
The works also included cabling to well heads to supply power and integrate pumping with the MSP controls.
Contract
A construction Contract was awarded to Phoenix by Cemex under the NEC3 Engineering and Construction Contract Option A. Phoenix undertook the role of Principal Designer and Contractor.
Work included the full design and construction of the methane stripping plant including all Process, Civil and MEICA Engineering Works plus integration of well pumping.
Treatment Plant
The tank is all GRP and consists of 4 off reactor chambers and a final discharge chamber all encased in a bund for compliance with CIRIA 736. The site electrical supply was changed to a TT system from a TN-C-S system to comply with hazardous area regulations and BS7671.
Phoenix installed a completely new electrical control and automation system within a containerized control building, remote I/O and control panels.
Duty/ standby blowers supply air for the stripping process with airflow gauges and adjustable flow rates. Duty/ standby pumps discharge the treated effluent to the sewer.
Instrumentation
Instrumentation was installed for flows, depths, and alarm levels.
The whole plant was linked back to the Phoenix DLOG SCADA system for operator interfacing and control, with full remote access.
DLOG records flows, stop/starts, levels and status. All data is exported daily to the Cemex central logging system.
The plant is designed to treat 50m3/day of leachate, pumped from eight extraction wells in the landfill. It can reduce dissolved methane from concentrations of up to 15 mg/l to below 0.14 mg/l, before discharging to the sewer.
New Containerised Control Room
The containerised control room has one compartment that houses the blowers and another for power distribution and controls.
New Gantry Arrangement
Phoenix designed and fabricated a new gantry arrangement in our workshop, which we then installed for access, and to support new control panels and instruments.
