What is Leachate pumping?

Leachate pumping is the process of collecting and removing the harmful water containing hazardous chemicals and biological materials from landfill sites.

What is leachate?

Leachate in the context of a landfill site is the hazardous liquid that contains harmful bacteria, chemicals and other components after being in contact with waste landfill material. This water can come from rainfall passing through landfill sites, or it can come from the natural decomposition process that occurs on a landfill as part of the organic matter breaking down.

Is leachate harmful?

Leachate is very harmful to the environment if it is not collected, treated and disposed of correctly. Leachate can contain heavy metals, chloride, complex organic contaminants and compounds such as chloride, ammonia, zinc and iron. If leachate is allowed to enter groundwater then it can travel into local rivers and even the local population. This can have a significant impact on the wildlife and environment in that area. Landfill operators can also face large fines in the event that leachate is allowed to flow into the local surroundings and infiltrate groundwater supplies.

Leachate collection

Leachate collection is usually a part of the initial design process of a landfill site. Liners are added to the landfill site to stop any leachate from leaving the landfill. These liners are made from a number of different materials, each designed to trap and contain the leachate to avoid any pollution escaping into the local area.

The liners collect the leachate below the surface of the landfill site, in addition to liners the landfill needs a way to remove the leachate to avoid it overflowing and escaping. Pipes are used at the bottom of the landfill to collect the leachate and store it until there is enough for it to be pumped out of the landfill and treated accordingly. The pipes that sit at the bottom of the landfill are under immense pressure from the heavy load above. These pipes must be strategically placed and designed to withstand large pressure. This can be achieved with either flexible or very strong inflexible pipes.

Leachate pumping

Once the leachate has been collected in the pipes or collection system and there is enough of it to remove from the landfill the leachate pump comes into use. Leachate pumps perform the task of extracting the leachate from the bottom of the landfill where it is contained within the pipes and pump it to the surface where it can be treated before being disposed of in a way that protects the environment. At QED we offer a number of leachate pump solutions that can help businesses effectively remove leachate. Find out more about our leachate pumping.

Leachate treatment

Once the leachate has been collected it must be treated to remove the harmful contaminants before it can be disposed of without causing harm to the environment. The most common way leachate is treated is onsite at the landfill. Leachate is extracted into treatment tanks where chemicals are added to change the pH levels and remove the solid matter to minimize the level of hazardous materials in the leachate. The process can be complex and require several stages depending on the exact makeup of the leachate. Biological treatment may also be used to further remove pollutants.

Disposing of the treated leachate

Even with extensive treatment and cleaning, the resulting leachate is very rarely clean enough to release directly into the local environment. It must be taken to the local sewage treatment facilities to be further assessed and disposed of correctly. This is usually done through pipes that go directly from the landfill site into the sewer.

Re-injection into landfill

Another method to manage leachate is to reinject it back into the landfill, this quickens up the decomposition process of the landfill waste. The result is an increase in biogas, which can be used to make money by cleaning it an reinjecting it back into the grid. Some of the leachate becomes biogas as part of this process, removing the need to then treat and dispose of this leachate. However the leachate does not get fully transformed into biogas, this leaves behind  leachate with a very high concentration of pollutants which can be hard to treat and dispose of.

Found in:
Environmental and Remediation