Application: Landfill Leachate

Electrochemical Oxidation for Landfill Leachate Treatment

High-strength, multi-contaminant leachate from active and legacy landfills — combining PFAS destruction, COD reduction, and ammonia oxidation in a single treatment step or as part of a broader treatment train.

See the Bench Test Approach

The leachate treatment challenge

Why leachate is one of the most demanding treatment applications

Landfill leachate is not a single waste stream — it is a complex, variable mixture of dissolved organics, ammonia, heavy metals, and increasingly PFAS from legacy firefighting foam and consumer product disposal. It resists biological treatment when COD is highly recalcitrant, when ammonia concentrations are toxic to biology, or when PFAS is present and must be destroyed rather than removed. Electrochemical oxidation addresses all three targets in one technology — though the relative priority of each shapes the system configuration. See Pollutants for contaminant-level detail.

Why EO fits leachate

Why electrochemical oxidation is well-suited to landfill leachate

Multi-contaminant treatment

A single EO step addresses refractory COD, ammonia (via active chlorine in high-chloride leachate), and PFAS simultaneously — reducing treatment train complexity.

No sludge from destruction

Leachate biological treatment produces large sludge volumes that are difficult to manage. EO produces no sludge from the oxidation reaction itself.

PFAS destruction in-situ

Legacy landfills are among the most significant PFAS sources. EO via BDD destroys PFAS without producing a secondary PFAS waste stream — directly responsive to CERCLA exposure.

Containerised and scalable

Leachate volumes vary. Containerised EO skids can be matched to actual leachate generation rates and scaled as landfill conditions change.

Bench testing for leachate

What leachate bench testing must establish

Leachate bench testing is more complex than single-contaminant applications because of the competing oxidant demand from COD, ammonia, and PFAS simultaneously. The bench test must establish the current density and residence time required to hit each target in the actual leachate matrix — not in synthetic solutions. Leachate composition varies by season and landfill age; bench testing at multiple time points is advisable for new installations.

See Engineering Process
  • COD removal rate at operating current density in actual leachate
  • PFAS removal and defluorination efficiency in the COD-present matrix
  • Ammonia oxidation efficiency vs. chloride concentration in the leachate
  • Competing oxidant demand: how COD loading affects PFAS and ammonia targets
  • Seasonal matrix variation — bench at different leachate ages if possible

Key parameters

Leachate-specific operating parameters

Landfill leachate typically has high conductivity — favourable for EO energy efficiency. High chloride content drives ammonia oxidation via active chlorine but may also generate chlorinated organic byproducts that must be monitored. The COD-to-PFAS priority must be defined before sizing — the two targets have different operating requirements.

See Engineering Process
  • High leachate conductivity reduces resistive losses — energy-favourable
  • Chloride concentration determines ammonia oxidation pathway and rate
  • Pre-treatment for suspended solids and heavy metals is typically required
  • Byproduct monitoring: chlorinated organics, bromate (if bromide present), fluoride from PFAS

Regulatory context

Leachate regulatory drivers

PFAS in landfill leachate is directly in scope of CERCLA designation. Landfill operators are both a release source and a potential responsible party under CERCLA for PFAS reaching groundwater through leachate. Discharge limits for leachate COD, ammonia, and emerging contaminants vary by permit jurisdiction — some facilities face tightening limits at permit renewal while also managing legacy PFAS liability.

See Regulatory Watch
  • CERCLA PFAS designation applies to landfill operators as potential responsible parties
  • Leachate discharge permits vary significantly by state and receiving water classification
  • Ammonia limits in leachate permits are tightening in sensitive receiving waters
  • Combined PFAS + COD + ammonia targets are increasingly written into new permit conditions

Related resources

Related resources

Pollutants

The contaminant-level mechanism and performance context for this application.

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Industry Solutions

The industry context behind this application and its regulatory driver.

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Case Studies

Deployed system results from this application area.

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Literature

Peer-reviewed research on EO for this specific contaminant class.

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Common questions

Electrochemical Oxidation for Landfill Leachate Treatment FAQ

Yes, but the system must be sized to the most demanding target and the operating parameters optimised for the matrix. High COD creates competing oxidant demand that increases energy consumption per unit PFAS removal. Bench testing with the actual leachate establishes where these trade-offs lie for your specific site.
Significantly, yes. Leachate from active landfills with high organic loading behaves differently from stabilised leachate from older sites. A system sized from bench data at one leachate age may need adjustment as the landfill matures. This is addressed in the sizing methodology.
Both configurations are used. EO as a standalone step suits lower-volume, high-concentration streams where the COD-to-PFAS ratio allows a single-pass approach. For high-volume leachate with very high COD, a biological pre-treatment step followed by EO polishing for recalcitrant organics and PFAS is more cost-effective.

Multi-target sizing

Leachate bench tests cover all three targets — COD, PFAS, and ammonia — in the actual matrix, not synthetic proxies.

Seasonal considerations

Leachate matrix variation is built into the bench test design where site data supports it.

PFAS-explicit

Every leachate application that involves PFAS is treated under the same rigour as the standalone PFAS application — BDD electrode, defluorination monitoring, byproduct profiling.

Start with the wastewater and the required endpoint

Request a Landfill Leachate EO Review

Provide leachate age or source, COD, TOC, ammonia, chloride, alkalinity, conductivity, color, metals, flow variation, existing biological or membrane treatment, and the required polishing endpoint. Byproducts and ammonia pathways require explicit review.

Submitting this form does not schedule testing or establish treatment performance. Uploaded files are used to review application fit and define the next technical step. Replace the placeholder email, webhook, privacy-policy link, and retention settings before publication.

Managing leachate PFAS liability or a permit renewal?

Tell us your leachate characteristics and the compliance driver — we will design the bench test to address all relevant targets in your actual leachate matrix.

Discuss Your Leachate Challenge

Include in your request

  • Site type: active landfill, closed landfill, or both
  • Leachate characterisation data if available: COD, ammonia, PFAS profile, chloride
  • Primary compliance driver: PFAS destruction, COD limit, or ammonia limit
  • Current treatment if any, and where it falls short
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