A landfill gas collection system can be running and still be underperforming. A blower may be online and wells may show vacuum, yet gas can escape through the cover, air can enter the waste, condensate can restrict flow, or parts of the wellfield can remain poorly collected.

The first response should not automatically be “add more vacuum” or “drill more wells.” Underperformance is often a system problem that needs coordinated review of the extraction wells, cover, piping, condensate controls, blower or flare station, operating data and the changing landfill itself.

Here are six operational causes to investigate.

1. The wellfield is out of balance

Landfill gas follows pressure gradients. Operators use wellhead valves and applied vacuum to influence where gas moves, but the system needs balance.

Too little extraction can allow gas to migrate or vent through the surface. Excessive extraction can pull atmospheric air through cover cracks, penetrations or the working face. That air can dilute collected gas and may create elevated oxygen and temperature conditions that require prompt investigation.

A well can show vacuum without contributing useful flow. Conversely, a high-flow well is not automatically well controlled if gas quality or surrounding conditions indicate air intrusion. Useful balancing looks at several measurements together, such as:

• wellhead vacuum and available header vacuum;
• gas flow;
• methane, carbon dioxide and oxygen;
• temperature; and
• nearby surface-emission or migration observations.

The target is stable, effective collection across the wellfield—not the highest possible vacuum at each point.

2. Air is entering through the cover or system

Cover integrity is part of the gas-collection system. Settlement cracks, eroded areas, dry fissures, open penetrations, poorly sealed well boots and active filling interfaces can create short circuits between the atmosphere and the extraction network.

Mechanical damage or construction around the wellfield can also open leakage paths. If operators compensate only by closing or opening well valves, the underlying cover defect remains.

Air intrusion should be investigated using the pattern in the data and a field inspection. Rising oxygen, falling methane concentration, localized high temperatures or unusual well response can be clues, but no single reading establishes the cause. Confirm instrument performance, inspect the wellhead and surrounding cover, and consider recent weather or construction activity.

Repairs may include restoring cover grades and thickness, sealing penetrations or cracks, repairing well boots, improving drainage or changing how active interfaces are managed. The appropriate repair depends on the cover design and the facility’s approvals.

3. Condensate is restricting the network

Landfill gas contains water vapour. As gas cools in headers and laterals, condensate forms. If it accumulates in pipe sags, low points, blocked traps or failed sumps, it can reduce or stop gas flow.

Symptoms can include fluctuating well vacuum, gurgling, sudden loss of flow in one branch, or a well that responds temporarily after condensate is removed. Seasonal temperature changes and settlement can make the problem intermittent.

An effective condensate review should consider:

• pipe slopes and settlement-related sags;
• trap, knockout and sump function;
• pump operation, alarms and power supply;
• frozen or blocked lines;
• liquid level in wells; and
• safe, authorized management of collected liquids.

Repeatedly draining a line without correcting the geometry or failed component may restore short-term flow but not system reliability.

4. Wells, wellheads or piping are damaged or obstructed

Landfills move. Settlement can pull apart flexible connections, change pipe slopes, stress wellheads and damage buried infrastructure. Vehicles, snow clearing, construction and erosion can also affect exposed components.

Inside the system, scale, biological growth, sediment or liquid can obstruct piping and well screens. A damaged or flooded vertical well may have substantially less effective perforated length than its drawing suggests.

Routine inspection should look for disconnected or crushed piping, leaking flanges, broken gauges, corroded components, damaged valves, shifted wellheads and blocked sample ports. When a branch behaves unexpectedly, isolate the problem systematically rather than making repeated valve adjustments without diagnosis.

Maintenance records matter. A map of recurring failures can reveal settlement corridors, drainage problems or construction interfaces that deserve a more durable repair.

5. The collection layout has not kept pace with the landfill

A landfill is not a static vessel. Waste placement, interim cover, final closure, settlement, moisture and temperature change gas generation and the pathways available for gas movement.

A system that once performed well may lose coverage as filling advances or as cells change from active to interim or final cover. New lifts can bury or isolate components. Wells can become too shallow relative to the waste mass, or spacing that was adequate for one stage may not suit the next.

Operational planning should connect filling and closure schedules with gas-system phasing. This can include temporary collectors, horizontal trenches, new vertical wells, header extensions, well raising or abandoning, and modifications around future construction.

Before adding infrastructure, distinguish a true coverage gap from a maintenance or balancing problem. Surface-emission surveys, migration monitoring, well data, pressure observations and the current waste/cover geometry can help define the issue.

6. The blower, flare, controls or data system is limiting performance

The wellfield cannot outperform the station that draws and handles the gas. Blower capacity, turndown, fouling, inlet restrictions, flare availability, condensate carryover, unreliable controls or frequent shutdowns can limit collection even when wells and headers are in good condition.

Instrumentation problems can also hide the cause. A drifting gas analyzer, plugged sample line, failed flow device or inconsistent field procedure can create apparent trends that are not real—or conceal a trend that is.

Review station and monitoring performance together:

• available versus required vacuum and flow;
• blower operating range and maintenance history;
• filter, separator and knockout condition;
• flare or utilization-system uptime and constraints;
• alarm, shutdown and restart history;
• analyzer calibration and bump-check records; and
• data completeness, units and sensor locations.

If capacity is genuinely limiting, expansion may be appropriate. If downtime or data quality is the main issue, capital equipment alone will not correct it.

Diagnose patterns, not isolated readings

Landfill gas conditions respond to barometric pressure, precipitation, temperature, waste placement, cover work and other operating changes. One unusual reading deserves attention, but diagnosis improves when measurements are trended and compared with field events.

A practical review can combine:

1. wellhead vacuum, flow, gas composition and temperature;
2. header and station pressure/flow data;
3. condensate levels, pump cycles and alarms;
4. surface-emission and migration-monitoring results;
5. cover inspections and recent construction records; and
6. weather, filling and closure activity.

This integrated view helps separate generation changes from collection problems. It also makes maintenance priorities easier to defend: repair a confirmed leak, clear a restricted branch, restore condensate control or rebalance a zone before assuming the entire system needs expansion.

A practical next step

When capture performance declines, start with a structured diagnostic review. Validate instruments, trend the core wellfield variables, walk the cover and network, and compare anomalies with condensate, weather and construction records.

KBL supports landfill gas collection-system construction, operation and maintenance. A focused review can help owners distinguish an operational issue from a capacity or coverage gap and prioritize the next field action.

Frequently asked questions

Does applying more vacuum always improve landfill gas capture?

No. More vacuum can increase collection in one area but also pull air through the cover or active face, dilute the gas and create undesirable temperature or oxygen conditions. Adjustments should be based on wellfield data and surface conditions.

What can rising oxygen and temperature indicate?

They can be signs of air intrusion or oxidation, but sensors, sampling procedures and other site conditions also need to be checked. Elevated or changing readings should trigger the facility’s investigation and response process; they are not a diagnosis by themselves.

Why does system performance change with weather?

Barometric pressure, precipitation, freeze-thaw conditions and temperature can affect gas movement, cover permeability and condensate formation. Weather context helps operators interpret trends and distinguish temporary response from equipment or coverage problems.

Related article: Canada’s New Federal Landfill Methane Regulations