### MEMORANDUM

TO: Ron Jordan, EPA

FROM: Anna Dimling, ERG

DATE: September 30, 2015

SUBJECT: Notes from Meeting with Liberty Hydro on September 23, 2014

EPA held a meeting with staff from Liberty Hy dro on Tuesday, September 23, 2014 at 1:00 PM to discuss the operation and pe rformance of Liberty Hydro’s zero valent iron (ZVI) technology
for FGD wastewater treatment. Ta ble 1 identifies the people that participated in the meeting.

Table 1. Meeting Participants

Name Company
Affiliation Phone Number Email

Phil Farina Liberty Hydro, Inc. (419) 346-8848 phil.farina@libertyhydro.com Mark J. Kropilak Liberty Hydro, Inc. (610) 710-5381 mark@libertyhydro.com John G. Taylor Liberty Hydro, Inc. (304) 941-3020 john.taylor@libertyhydro.com Phillip Flanders EPA (202) 566-8323 Flanders.Phillip@epa.gov Jessica Hall EPA (202) 564-3376 Hall.Jessica@epa.gov

Ron Jordan EPA (202) 566-1003 Jordan.Ron@epa.gov

Jan Matuszko EPA (202) 566-1035 Matuszko.Jan@epa.gov Sharon DeMeo (phone) EPA/ Region 1 (617) 918-1995 DeMeo.Sharon@epa.gov Anna Dimling ERG (703) 633-1692 Anna.Dimling@erg.com TJ Finseth ERG (703) 633-1698 Thomas.Finseth@erg.com

This memorandum summarizes the meeting discussion points.

Introduction

Liberty Hydro, located in South Charleston, WV , was incorporated as a spinoff of the MidAtlantic Technology and Research Innovation Center (MATRIC) in 2010. Liberty Hydro, Inc. has a focus in wastewater treatment and developed the ZVI Blue TM reactive media (patent issued on March 11, 2014). Several bench- and pilot- scale experiments inte grating the ZVI Blue TM reactive media have been completed, including

 Coal mines;

 Patriot Coal in West Virginia and proj ect in Idaho (2009) - reduced selenium
concentrations in acid mine drai nage (AMD) to less than 5 ppb,

 Another West Virginia coal mine was a success, but coal mine closed during study,

 A nickel mine (Madagascar);

 99% Chromium removal,

 Discussions about Tanneries in Northern India;

 For Removal of Chromium,Memorandum October 30, 2015 Page 2

 Coal-fired power plants;

 Completed two pilot studies on FGD wa stewater that reduced selenium

concentrations to less than 10 μ g/L,

After completing the successful pilot-test studie s on flue gas desulfuriz ation (FGD) wastewater at coal-fired power plants, Li berty Hydro was asked by a company to design and prepare a cost estimate for a full-scale implementation with a chemical precipitation system, biological treatment system, and ZVI Blue TM system to treat FGD wastewater at a flow rate of 350 gallons per minute (gpm).

ZVI Blue TM Reactive Media

In general, the ZVI process removes pollutants by contacting wastewater with an iron powder, reducing the pollutant to its elemental form, a nd removing the pollutant. ZVI has been proven to remove several heavy metals from FGD wastewat er (i.e. arsenic, mercury, copper, chromium, etc.); however, the focus is on the removal of selenium in the sele nate, selenite, and other forms. The equations below demonstrat e the redox reaction where the ZVI donates electrons to the selenate (Equation 1) or selen ite (Equation 2), which are reduced to elemental selenium, which is
much easier to remove.

3Fe 0 (s) + SeO 4 2- (aq) + 4H 2 O (l) → 3Fe 2+ (aq) + Se 0 (s) + 8OH

- (aq) (Equation 1)

2Fe 0 (s) + SeO 3 2- (aq) + 3H 2 O (l) → 2Fe 2+ (aq) + Se 0 (s) + 8OH

- (aq) (Equation 2)

Specifically, the ZVI Blue TM reactive media is a system that c ontains fine ZVI shavings adhered to a porous polymer foam media. Moreover, the FGD wastewater is perc olated upwards through
several stacks of the ZVI Blue TM reactive media and the elemental selenium is captured within
the media.

First Pilot Study

A pilot study was performed at a coal-fired pow er plant. This study incorporated the ZVI
Blue TM reactive media after the FGD wastewater was treated by a rudimentary chemical precipitation and simple biological (Bio) system (see Figure 1).

Figure 1. Process Flow Diagram for the First Pilot StudyMemorandum October 30, 2015 Page 3

The study was performed from November 2013 through March 2014 and the FGD wastewater influent (1-2 gallons per minute (GPM)) to the pilot study was pulled from a settling pond; therefore, some total suspended solids (TSS) was being removed prior to treatment in the chemical precipitation system. At the beginni ng of the pilot study, there was no chemical precipitation system and the FGD wastewater (1-2 gpm) was sent directly to the biological treatment system following the settling pond. After some time and because none of the pilot tests were performing well, the rudimentary chemical prec ipitation system was added to the pilot test. The chemical precipitation system consisted of lime, ferric chloride, and polymer addition, followed by a settling basin to remove the sludge. The chemical precipitation effluent was then sent through a “simple” Bio system containing mi crobes specifically designed to remove nitrates
from the wastewater.

According to Liberty Hydro, the ZVI Blue TM system can remove nitrates, but the addition of a simple Bio system allows the microbiology to focus on the heavy removal of nitrates if present and a matter of concern, thereby allowing the ZV I process to selectively focusing on selenium and other metals without competition from nitrates. The ZVI Blue TM system consisted of a filter
and three or more reactor vessels containing media. Hydrochlor ic acid (HCl) was also added before the media tanks for alkalinity and bu ffering. After the addition of the chemical precipitation system, the ZVI Blue TM pilot study demonstrated a se lenium removal greater than 99% and consistently contained less than 10 μ g/L selenium in the treated wastewater.

Second Pilot Study

Liberty Hydro participated in a 12-week pilot study at a coal-fired pow er plant from March 2014 through July 2014. The plant has a full-scale chemi cal precipitation system for treating its FGD wastewater prior to discharge; therefore, the pilot test was co nducted on the effluent from the chemical precipitation system. Th e FGD wastewater at the plant does not contain a large amount of nitrates, so Liberty Hydro chose to run th e pilot study without the “simple” bio system or other type of pre-treatment scavenger unit. However, Liberty Hydro recently submitted a proposal to continue running at the plant with the addition of a “simple” bio system. Liberty Hydro noted that the pilot test unit was still intact at the plan t at the time of this meeting.

The influent into the system was 1-2 gpm and the treated wastewater was sampled two times every week. Over the 12 week time period, the av erage selenium concentration in the treated
wastewater was less than 10 μ g/L (all the readin g were below 10 μ g/L except one reading that was presumed invalid). After the 12-week study was complete, Liberty Hydro proposed to
increase the flow rate to the pilot system beyond the design para meters to determine at what point the system would “break” (i.e., at what flow rate woul d the system not achieve 10 ppb selenium). According to Liberty Hydro, when the in fluent flow rate was increased to 4 gpm, the
selenium concentration increased to above 10 μ g/L; but the system was still removing the vast majority of selenium.Memorandum October 30, 2015 Page 4

Future Full-Scale Treatment System

Liberty Hydro is in the process of drafting a de sign for a full-scale FGD wastewater treatment system with an engineering firm. The initial full -scale design consists of a chemical precipitation system, “simple” Bio system, ZVI Blue TM system, and filtration system. The full-scale model will be designed for a FGD wastewater flow of 3 50 gpm. The bio system will consist of a reactor containing carbon-rich media a nd microbes, which utilize the carbon and nitrates as energy
sources. The ZVI Blue TM system, in its initial design, was to contain 15 react or vessels that contain stacks of media (see Figure 2). Ad justments to the design configuration will be
evaluated over time.

Figure 2. Full-Scale Design Proces s Flow Diagram for the ZVI Blue TM System

The reactor system is designed in a way that if any particular stack of media is not operating properly, that particular stack can be removed and repaired wit hout causing a system shut-down. Liberty Hydro is still working on methods for cleaning and regenerating the media and if the cleaning wastewater can be recycled back into the system. Liberty H ydro indicated that the media is able to last anywhere between 6 mont hs to 5 years and more studies need to be performed to refine the longevity estimates for different operating condi tions. Liberty Hydro has been collaborating with an engineering firm to prepare capital and ope ration and maintenance (O&M) cost estimates for the system.