How algae are solving the landfill leachate crisis.
Landfill leachate remains one of the waste sector’s most persistent operational and environmental challenges. Robert Mitchell, co-founder of ENV Tech, says while everyone in the industry understands the issue, very few would suggest it has been definitively solved.
For decades, landfill operators have relied on a familiar mix of storage, evaporation, irrigation and off-site disposal to manage leachate volumes and reduce the risk of overflow.
In some cases, these approaches remain workable. In others, they are becoming increasingly difficult to justify, scale or defend.
Robert says this is particularly evident as sites require expansion, rainfall patterns intensify, and regulatory expectations continue to tighten in response to complex contaminants of concern.
As a result, many legacy facilities are now operating with infrastructure that is no longer fit-for-purpose. At the same time, new projects and developments are facing delays or redesign, as operators are increasingly required to answer a fundamental question from regulators: “What are you going to do with the leachate?”
Compounding this is a deeper understanding of leachate itself. Hydrological variability is increasing, and contaminant profiles are becoming more complex, with ammonia nitrogen, metals and per- and polyfluoroalkyl substances (PFAS) now routinely requiring consideration.
“The issue is no longer one of storage alone but a shift toward reliable, cost-effective engineered solutions that can consistently perform,” says Robert.
Biological Leachate Remediation (BLR) is an engineered system designed to actively treat and control leachate as part of a broader water management framework. It was developed by BLR Tech, an ENV Solutions company offering environmental consultancy and remediation.
“Put simply, BLR is a staged process that combines chemical conditioning, algal-based biological treatment, physical separation, polishing and disinfection into a single, integrated treatment process,” Robert says. “These unit processes are brought together to address leachate composition variability and complexity.”
At the centre of the process is a controlled biological system. BLR uses an algal process to drive ammonia nitrogen removal, enabling the system to respond to changing leachate conditions rather than relying solely on fixed mechanical processes or conventional biological approaches.
Robert says that in practice, this means the leachate pond itself becomes an active part of the treatment process, rather than simply a storage asset.
“From an operational perspective, this has several positive implications. It reduces reliance on high-energy treatment systems, with algal processes contributing dissolved oxygen through photosynthesis and supporting biological treatment pathways,” he says.
“It allows existing infrastructure to be incorporated into the treatment framework. It also introduces a level of seasonal adaptability that is often difficult to achieve with more rigid treatment configurations.
“From a regulatory perspective, the process has been demonstrated at scale, treating more than 700 kilolitres of landfill leachate per week to environmentally compliant standards, enabling beneficial reuse or irrigation outside of active landfilling areas.”
Since its initial development in 2022, the technology has been progressively refined and validated under operational conditions.
In 2023, BLR was recognised by Engineers Australia, receiving Project of the Year (Newcastle) for its work in remediating catastrophic flood damage caused to Lismore’s landfill and sewage plant, which resulted in more than 20 million litres of polluted water.
A collaboration with NSW Public Works – Department of Regional NSW, the project was singled out as a method that could be adapted for other water cleaning tasks.
But Robert says while industry recognition is notable, the significance lies in demonstrating that a treatment-led approach to landfill leachate can be implemented, validated and operated in practice.
“Demonstrating that the BLR process could treat leachate to environmentally compliant standards was the first step. Designing a BLR system that can operate reliably, anywhere within Australia, under real long-term landfill conditions is another,” he says.
“BLR 2.0 represents that transition toward an automated, purpose-engineered solution.”
Given inflows and contaminant profiles vary significantly from site to site, BLR 2.0 has been designed to be modular, scalable and durable. A modular design of one, two, four and eight litres per second allows the system to evolve as site conditions change. Operating in a harsh environment, BLR 2.0 is constructed predominantly from inert materials such as high-density polyethylene (HDPE), unplasticised polyvinyl chloride (uPVC) and fibreglass – allowing a design life of up to 25 years.
Operational requirements have also been central to the design.
“Many landfill sites, particularly in regional areas, do not have the labour capacity or budget to manage complex treatment systems on a continuous basis,” Robert says.
“BLR 2.0 has been developed as a low-attendance system, with automation, monitoring and control embedded into the overall process. This reduces the need for constant operator intervention and associated costs, while maintaining plant performance, consistency and traceability.
“In this context, BLR 2.0 is not simply an iteration of the original process. It reflects a broader progression toward leachate treatment systems that are integrated into site operations and capable of adapting to changing conditions over the life of a landfill.”
For more information, visit www.envsolutions.com.au
.png){kind=small}
.png){kind=small}
