The Challenge

As per- and poly-fluoroalkyl substances (PFAS) are being detected in the environment and in food and water supplies, a focus on landfill leachate is growing.

However, PFAS removal from leachate is particularly difficult to treat due to complex chemistry, inconsistent feed quality, suspended solids and varying flow rates of leachate.  In the past, the options available to treat the PFAS-contaminated leachate were limited and typically required comprehensive and expensive pretreatment.

In 2022, one of the largest solid waste companies in the United States invited the Australia-based Water and Carbon Group (WCG) and its US partner, Leachate Management Specialists (LMS), to demonstrate a new PFAS removal system at a Virginia landfill site.

The five diverse leachates, including a reverse osmosis concentrate (ROC) stream, were highly co-contaminated with:

Total Nitrogen ranging from ~500 mg/L to more than 3,000 mg/L
Total Dissolved Solids (TDS) between ~14,000 mg/L and 54,000 mg/L
Chemical Oxygen Demand (COD) from ~2,000 mg/L to 84,000 mg/L
Alkalinity ~1,500 mg/L to 11,600 mg/L
In addition:
PFOA was between ~140 and 12,500 ng/L
PFOS ranging from <10 ng/L to over 3,600 ng/L



The Solution

Australian company the Water and Carbon Group (WCG) developed the LEEF System® (Low Energy Evaporative Fractionation) to remove PFAS from complex waste streams using minimal energy and no chemicals or consumables. Utilizing foam fractionation, the system removes up to 100% of targeted compounds and is effective without costly pre-treatment.

The LEEF System® is modular, so it is easy to scale up to fit a facility’s needs. This flexibility allows the system to be customized to meet site-specific challenges for different leachate characteristics and flow. The flexible and robust modular system can be assembled to treat any volume from 5,000 gpd to 500,000+ gpd.

The technology has already been successfully deployed at a landfill leachate treatment plant in the northern Australian city of Darwin, which is subject to tropical monsoons, depositing over 4’ of rain in a few months. The LEEF System® in Darwin is successfully treating 36,000 gallons of complex leachate each day, in a zero liquid discharge operation.

To show the capability of the LEEF System® in the US, WCG constructed a mobile demonstration scale system that consists of four commercial sized fractionators housed in a 40-foot shipping container.



Results

Following a successful initial deployment in Tennessee for another solid waste company, the system was re-commissioned at the Virginia landfill site. The demonstration LEEF System® treated the five diverse leachates and ROC successfully, shown by consistently removing PFAS compounds to below limits of detection, which ranged from <2 to <398 ng/L, while concentrating them in the small volume of foamate.

Test results included (all in ng/L):
PFOA in raw ROC: 8,300
Treated: <11
Foamate: 217,000
PFOA in raw leachate: 2,080
Treated: <4.4
Foamate: 11,700
PFHpA in raw leachate: 398
Treated: 4.9
Foamate: >4,500
PFOS in raw ROC: 659
Treated: <10
Foamate: 6,000
PFHxS in raw ROC: 1,990
Treated: <11.9
Foamate: 78,200

In addition to priority compounds, the demonstration was also able to deplete other PFAS that were initially present in the leachate streams, including PFBS, PFHxA, 6:2 FTS, 5:3 FTCA, and others.
To discuss how the LEEF System® can be used to treat leachate and industrial wastewater, or to arrange a demonstration at your site in the United States, contact us.