South Texas Landfill Case Study During 2011, four QED Precision Fine Tune Control Valves were installed in wells at a south Texas landfill. The following graphs show the composition of the landfill gas and flow data before and after the installation of the Control Valves in Wells 07, 54, 78, and 90. The closest neighboring well on the same trunk line, using a gate valve for flow control, was also chosen for an additional comparison. The screen shot (at right) shows the increase in value of the methane produced at Well 90 resulting from the increase in concentration and flow.
Well 07 Complete Wellhead Installation The new QED Wellhead installation on Well 07 has reduced balance gases and maintained the flow of methane. After installation of the Wellhead and Control Valve on Well 07, balance gases have been reduced and the flow of methane was maintained or steadily increased. Because of high oxygen levels, neighboring Well 08 has been and remains in exceedance of NSPS regulations. Well 08 neighbors Well 07, and does not have a QED Control Valve. With its oxygen concentration issues it is continually out of compliance.
Well 54 Fine Tune Control Valve Installation The QED Control Valve installed on Well 54 has reduced the balance gas concentration and increased methane production. Well 54 had several compliance issues in 2010, such as oxygen levels spiking to 20% in December, prior to the installation of the Control Valve. After installation, methane production has increased, and the oxygen concentration has been reduced keeping the Well in compliance. Neighboring Well 55, on the same trunk line, continues to have big spikes in balance gases and big drops in methane production. Well 55 neighbors Well 54, and does not have a QED Control Valve, it has major compliance issues because of oxygen spikes.
Well 78 Complete Wellhead Installation The new QED Wellhead installation on Well 78 has reduced oxygen and balance gas concentrations, and steadily increased methane production. Well 78 also had compliance issues in 2010. But once the Wellhead and Control Valve were installed, methane production has been steadily rising, and balance gas and oxygen levels have been reduced. Well 78 now remains in compliance. Neighboring Well 25, on the same trunk line, had flow, balance gas, and oxygen spikes in early 2012 putting it out of compliance. Well 25, which is a neighbor to Well 78 and does not have a QED Control Valve, has been out of compliance because of oxygen levels.
Well 90 Fine Tune Control Valve Installation The installation of a QED Control Valve put Well 90 back in compliance by controlling oxygen concentrations. Prior to the installation of the Control Valve, Well 90 was out of compliance because the oxygen concentration had increased to 6.4%. After installation, oxygen levels have been reduced helping maintain compliance, and methane production has increased. Neighboring Well 29, on the same trunk line, has had continuing compliance issues. Well 29 is a neighbor to Well 90 and does not have a QED Control Valve, it has continuing oxygen concentration compliance issues.
Case Study Conclusion The installation of QED Wellheads and Fine Tune Control Valves has clearly helped this south Texas landfill to improve gas flow and maintain compliance. All four of the wells had a reduction in balance gas and oxygen concentrations, and maintained a steady flow of methane. Vacuum was maintained on the wells resulting in additional methane collected over the entire time range of the study. The QED Fine Tune Control Valves allowed for linear flow adjustment even at flow rates under 10 cfm. The metered scale displayed the exact valve setting, with the rising stem making it clear how far the valve was open. In all cases, the Wellheads enabled the landfill to maintain measurable flow at the wells and keep oxygen under five percent.