Can biomass char remove toxic synthetic chemicals from drinking water?

Josh Kearns

University of Colorado / North Carolina State University

This project ended on:
15 August 2014
Toxic synthetic chemicals such as pesticides and pharmaceutical residues are a major threat to drinking water safety worldwide.

Low-cost, environmentally sustainable and locally managed treatment technologies are needed to protect human health in impoverished, rural and remote communities.

This research project demonstrates the potential of char made from surplus biomass (biochar) as an effective sorbent for chemical toxins.


Budget Overview

To complete this project, we need to purchase pesticide and pharmaceutical contaminant reagents for use in laboratory micro-column tests.

The reagents are expensive because they are labeled with radio-chemical tags. The tags allow us to detect the contaminants at very low levels (parts-per-trillion!) when they are dissolved along with background natural organic matter in typical surface waters.

The particular test compounds we select for column experiments will be based upon:

(1) their widespread use, environmental persistence, and frequent detection in water sources,

(2) their associated deleterious human health impacts, and

(3) their difficulty to remove from water by adsorption relative to most other synthetic chemical contaminants.

Point (3) signifies that if treatment using biochar is effective for removal of our selected challenge compounds, it will likely also be very effective for removal of a host of chemical water pollutants.

We will also purchase special kits for detection of our target compounds using an alternative biochemical method. These kits will be used as a cross-check to verify our primary quantitation protocol.

The kits offer the additional capability for compound detection in the field, and will be used to validate our modeling and scale-up approach for translating laboratory data to predict the performance of real-world biochar treatment systems.

We also require a small budget for lab micro-column hardware, and supplies such as tubing and sampling equipment.

Meet the Researcher


I started working on sustainable, low-cost water treatment while living with a small farming community in northern Thailand, near the border of Burma. The community did not have secure access to drinking water and wanted to use local surface water sources but were concerned about agrochemical runoff. They approached me to help them design a treatment system based on traditional methods using locally produced charcoal, and that's where it all began.

I soon discovered that no scientific research had been performed on the use of local chars for control of pesticides and other organic chemical toxins in drinking water. It was then that this project became my mission in life.

As far as hobbies go, I enjoy trail running, cycling, swimming, backpacking and bicycle touring. I am an enthusiastic beer homebrewer, and an equally enthusiastic craft beer drinker. Rumor has it that I am also a decent bluegrass mandolin player.


Please see Aqueous Solutions, in particular our page on charcoal / biochar water treatment where you'll find open-access video and print resources in several languages.

Making "low-tech" biochar adsorbent for decentralized water treatment, Chemists Without Borders.

An ancient filtration material removes pesticides from drinking water, Engineering for Change.

Selected publications:

Kearns JP, Knappe DRU, Summers RS. (2014) Synthetic organic water contaminants in developing communities: an overlooked challenge addressed by adsorption with locally generated char. Journal of Water, Sanitation & Hygiene for Development (in press).

Kearns JP, Wellborn LS, Summers RS, Knappe DRU. (2014) 2,4-D adsorption to biochars: effect of preparation conditions on equilibrium adsorption capacity and comparison with commercial activated carbon literature data. Water Research, Vol. 62, pp. 20-28.

Kearns JP. (2012) Sustainable decentralized water treatment for rural and developing communities using locally generated biochar adsorbents. Water Conditioning & Purification International.

Also, please "Like" Aqueous on Facebook!

A few photos showing drum ovens used for producing adsorbent biochar in rural villages, and incorporation of biochar adsorption units in multi-barrier treatment systems to address both biological and chemical water contaminants:

One of our trainees at a recent workshop in a village in eastern Burma:

Banner image: Scanning electron micrograph of a grain of char made from longan wood by traditional method in northern Thailand. The scale bar = 500 micrometers (0.5 mm). Note the highly porous structure of the char, providing plenty of internal sites for sorption of water contaminants.

A heaping tablespoon of crushed high quality water treatment char can have an internal surface area as large as a football field!

Project Backers

vargaDavidRhodesericnesbit313AmandaAykroidguillermoluque102BrianDoughertyJosh KearnsRobKearnsTraciBrooksOscar Jasklowskigregoryegan94Lachmikeescobar1kelpiewilsonKevinCarlinhadarnestelErichJKnightMaryCatonLingoldhollyvannormanjohnbonitzAlbertCloetexavierbkkfrancisdelosreyesamycolletteMorganShimabukuRachaelKearnsAyleeVogelAustaParkerDenny LuanMeagenGrundbergKeenaMullenLaurenWellborn