Case Studies

PFAS Removal System

March 25, 2024
By Sanjeev Erriah

Towards the end of 2021, SEEP Engineering was approached to design a pilot plant to reduce PFAS that have been detected in water sourced from bores. The water bores are located on residential and farming land in Biloela, Central Queensland. The design, undertaken by SEEP Engineering, was implemented and commissioned by mid-2022. Water analysis was undertaken and the test results indicated a 93% PFAS reduction which far exceeded the Client brief.

Treatment of PFAS – Contaminated Water

Introduction

Per or Polyfluoroalkyl Substances (PFAS) were developed in the 1940’s and used in various industrial and domestic products such as Firefighting Foam, Food Wrappers, Non-stick Cookware, Fabric and Leather Waterproofing, Thread sealing tape, Waterproof garments, Surfactants, Emulsifiers, Wetting Agents and Coatings.

PFAS is a man-made, synthetic chemical compound with over 4,000 PFA compounds and growing. PFAS is extremely persistent in the environment.

Both surface and ground waters may be contaminated.

Levels as low as 7 parts per trillion (ppt) are considered hazardous to humans. 1 ppt is equivalent to 1 grain of sand in an Olympic size swimming pool.

The Australian Drinking Water Guidelines (Version 3.8) has set a limit of 0.07 μg/L.

Health

As per School of Environmental Health, University of British Columbia; PFOA (Perfluorooctanoic acid) may be associated with:

High Cholesterol,
Liver and thyroid issues,
Decreased vaccination response,
Cancer, and/or
Hypertension while pregnant.

PFOS (Perfluorooctane sulfonate) may be associated with:

Increase in total cholesterol, triglycerides, and uric acid,
Reduced female fertility and male sperm quality,
Reduced birth weight,
ADHD, and/or
Changes in thyroid hormone levels.

Exposure to the PFAS/ PFOS could be through:

Ingesting of food and water,
Use of affected or contaminated products,
Inhalation of contaminated dust or vapors, and/or
Working in or exposure to the manufacturing process.

Problem

Methodology

SEEP Engineering reviewed the water test results which indicated that the PFAS concentration level recorded was in the order of 0.148 µg/l

The client’s objectives were to:

Achieve a reduction in PFAS by 60-80%; and
The PFAS water removal and treatment system is to be simple and easy to manage.

SEEP Engineering reviewed the various technologies commercially available to remove PFAS. These include:

Granular Activated Carbon (GAC),
Ion Exchange (IX),
Low Pressure Membranes – Microfiltration and Ultrafiltration (MF/UF),
High Pressure Membranes (RO), and
Closed Circuit Reverse Osmosis (CCRO).

After review of the various technologies, SEEP engineering selected a combination of two available technologies (GAC and IX). The technologies were engineered and sized based on the water flow requirement.

Results

The design, undertaken by SEEP Engineering, was implemented and commissioned by mid-2022. Water analysis was undertaken and the test results indicated a 93% PFAS reduction which far exceeded the Client brief.