Landfill sump pumping tests

At HydroTerra, we are noticing a significant increase in demand for landfill sump pumping tests. The purpose of these tests is to investigate the effectiveness of the leachate sumps and the performance of the connected leachate collection system.  Leachate collection systems do fail, and the causes are many and varied. These include: bio clogging of drainage lines and layers, sump collapse caused by waste consolidation and consequent sump movement, pump failure due to clogging, overheating and general poor maintenance, to name a few.

Operators and regulators become concerned when their leachate extraction systems fail to function optimally. Such issues can have a significant impact on the accumulation of leachate within the landfill cell and the head of leachate on the liner.  This is a common license criterion on landfills, which requires maintaining this level at or less than 300mm depth of leachate on the liner.

At HydroTerra, we take on two essential roles in delivering pumping tests: providing an optimal monitoring setup to measure key parameters, and deploying field technicians to collect measurement data.

Recently, we held a meeting with select hydrogeologist consultants to gather valuable insights into what the optimum monitoring equipment for pumping tests should look like. The key parameters for any pumping test include:

• Drawdown in the sump/well (m). With respect to level measurements in the sumps, we offer two options. The first option involves level measurement using absolute pressure transduces with barometric compensated level readings. Alternatively, we can provide bubblers which can be easier to deploy when there is limited space in the sumps or pumping wells.
• Flow rate being delivered from the pump (L/sec). In the case of measuring flow, the preferred option is the use of electromagnetic flow meters. HydroTerra provides expert field technicians who can connect the necessary plumbing.

There are also a range of ancillary measurements deemed useful:

• Standard water quality parameters (i.e. pH, Electrical Conductivity and Temperature). These can be measured using flow-through cells connected to the discharge line.
• In-line pressure, which provides information on the pump performance.
• Barometric pressure.

A critical aspect of our service is the ability to remotely collect this data via our DataStream data hosting facility. This feature allows the project team to stay informed about the operational status of the pumps, while allowing remote decision making on when to cease pumping once water levels have stabilized or setup automated triggers and remote control.

When it comes to providing data, HydroTerra ensures time series data with time stamps, synchronised across all measurement devices used. This makes subsequent analysis relatively easy. We firmly believe that our service complements the expertise provided by hydrogeologists, who specialise in interpreting pumping test data.

For further information on our pumping test rental equipment and services, please contact John Guo, Rental Manager at HydroTerra on 03 8683 0091.