COLLEGE OF ENGINEERING Chemical, Biological & Environmental Engineering

BIOCHAR FOR INDUSTRIAL STORMWATER MEDIA 2.0

Jon Laurance, Isabella Lewis, Danielle Whitehurst

Methods

● 15 wt% solid humic acid ● 25 wt% solid humic acid ● 25% compost with 5% iron ● 25% bokashi● Biochar soaked in 20 vol% acetic acid for 24 hours● Biochar soaked in fulvic acid for 24 hours● 25% peat● Biochar

● Determine an alternate locally sourced biochar mixture to replace peat that has a comparable adsorption capacity for zinc and copper

1. Mixture Preparation: Sieve and grind biochar mixtures

5. Use ICP-OES to determine final zinc and copper concentrations

4. Vacuum Filter samples

3. Batch Testing: Synthetic stormwater with zinc and copper concentrations of 0.5 ppm, 1 ppm, 2 ppm and 3 ppm were added to the bottles and tumbled for 48 hours.

2. Batch Preparation: Create 50 mg mixtures using a mass balance and expose the mixtures to air for 24 hours to enhance microbial reactions

ICP vial

Vacuum

0.45 μm filter

Previous CBEE 416 group (Kimmel, Hannah, Ovesen, Stearns, 2013) measured biochar specific surface areas up to 800 m²/g

John Miedema making biochar in Philomath, OR.

● John Miedema, owner of BioLogical Carbon, LLC makes biochar for stormwater remediation columns and soil amendments

Acknowledgments● John Miedema for providing biochar, bokashi, humics, iron, and

fulvic acid● Dr. Nason for providing experimental guidance, lab space, and

materials● Sarah Burch and Joy-Marie Gerould for experimental guidance &

lab assistance● Andy Ungerer for information & help with ICP● Turf Team- Sarah Frey, Jenny Green, Caitlin Inman for teaming up

for ICP tests● Dr. Azizian for assistance in using the sample tumbler● Dr. Harding for experimental guidance

Purpose

Zinc and copper are regulated by industrial stormwater permits, which are becoming more stringent. Remediation methods must improve to meet permit levels. Currently, biochar is used with peat moss as an adsorbent in filters, however peat moss is not a sustainable material as it is mined in Canada.

What is Biochar?● Organic matter heated to

1200 °C for 15 seconds in an oxygen limited environment to remove water and volatile species

● High amount of surface area to adsorb many ions

Our Sponsor

Phenolate group

Carboxyl group

Biochar Mixtures Tested

Acidic materials functionalize the biochar surface by adding phenolate and carboxyl groups that bind strongly to metal cations.

Three potential isotherm models were investigated to predict mass of metals adsorbed as a function of equilibrium concentration.

● His previous research has shown biochar mixed with peat moss is more effective at adsorbing metal cations than biochar alone in packed bed column tests

Process Design

Conclusions

● A column with a 5 year life will be designed to treat stormwater from a 5,000 ft² galvanized roof in Corvallis, OR, with Zn2+ stormwater concentrations of 500 µg/L.

● Currently considering 25 wt% solid humic acids mixture● Filter cross sectional area designed based on peak flow and pressure drop● Column height designed based on adsorption data

● Compost, bokashi, and soaked biochar mixtures did not perform as well when compared to biochar alone

● Biochar, 25 wt. % solid Humic acid and 25% Peat biochar mixtures have statistically similar removals

● The next project phase could investigate column tests with biochar, 25 wt.% solid humic acid and 25% peat biochar mixtures

● The team recommends copper, zinc and dissolved organic carbon concentrations to be measured during column testing

Peat mixture had highest zinc

adsorption capacity.

At equilibrium concentrations

above 0.25 ppm, compost has the

largest zinc adsorption capacity

Biochar and peat/biochar mixture had highest copper adsorption capacity

Adsorption capacity for acid soaked biochars were smaller than peat biochar mixture and biochar alone for both copper and zinc.

Results25 wt% humics have higher copper adsorption capacity at the concentrations investigated.

BioLogical Carbon, LLC peat/biochar column located near First Alternative Co-op in Corvallis, OR