## Liberty Hydro Explanation o f Technology:

F or application to flue gas desulf urization wastewater at coal burning power plants

Introduction

Liberty Hydro

, Inc. has developed a reactive media designed to reduce selenium (in all forms) from FGD

wastewaters , using zero v alent i ron (ZVI) on a reticulated foam substrate. The ZVI system will reduce heavy metals and entrap the contaminants within the media matrix, producing a wastewater able to meet the proposed effluent guidelines.

The technology , termed ZVI Blue TM , was installed at several coal burning power plants during 2013 and
2014. When used effectively, ZVI Blue TM is the anchor technology in a three step treatment train consisting of 1) Physical/Chemical treatment followed by 2) a simple bio system (to remove nitrates), followed by 3) ZVI Blue TM reactive media to remove selenium and other metal contamina nts

. The testing was designed to determine effectiveness of the three stage treatment process and to determine cost effectiveness of the concept. The results showed that the proposed three stage treatment system can be optimized to meet the proposed effluent l imits and can be done so

, cost effectively.

Liberty Hydro was established in 2009 and has focused its efforts to develop advanced technologies to reduce selenium, mercury and arsenic from wastewaters in coal mines and coal burning power plants. In 2013, Liberty Hydro evaluated waters from numerous power plants in North America . That analysis showed that the best treatment option is a three step trea tment train as described above, which we believe is the foundation for Best Available Technology.



## FGD Was tewater Treatment Evaluation
Evaluation of wastewaters from several power plants showed the material to be:

 Variable in pH, ORP and degree of TDS and TSS ;

 Sel enium levels were also variable due to factors such as type of coal, effectiveness of flue gas des ulfurization

, and seasonal factors ;

 Nitrate l evels were also highly variable;

 Most power plants do no t seem to use primary treatment to prepare their water prior
to release

.These

, and other factors

, add to the complex nature of the treatment required. A single solution, or

“ magic bullet ” , will not be sufficient or cost effective under all conditions to manage selenium from
these waste waters. As a result of this initial evaluation

, the use of a three step treatment train was
evaluated to treat FGD wastewa ters.


## Primary Treatment (physical/chemical)

Primary treatment of raw waters is a well

- known in the water and wastewater treatment industry. Primary treatment uses pH adjustment (lime addition) followed by the addition of coagulants (iron salts) and polymers (cationic, anionic or nonionic) followed by clarification and settling. Primary treatment
allows for the re moval of some metals, adjustment of pH and ORP (important in selenium removal) and the removal of TSS and TDS. Water thus treated is more uniform and thus is better for treatment by the
next stage treatments.


## Biological Treatment (nitrate removal)
Biolog ical treatment of FGD waters has been considered as a leading t echnology by the Environmental Protection Agency. Unfortunately, the variability of FGD contamination levels and lack of primary treatment all contribute to the difficulty of using one technolo gy to meet t he proposed effluent limits.

Liberty Hydro Inc. evaluated biological technology as a methodology to manage nitrates. Nitrates are
known to interfere, at some level, with selenium reduction from zero valent iron, s o Liberty Hydro used a simpli fied Up

- Flow Anaerobic Packed bed Reactor (UAPBR) as a method to reduce nitrates in preparation for the anchor technology

, ZVI Blue TM
, to remove selenium. Nitrates are also part of the proposed effluent guidelines so the use of a biological technology, to m anage nitrate, makes sense as part of an effective three step treatment train.

The biological system uses a specific blend of non GMO, class 1, naturally occurring consortia of microbes designed to specifically focus on nitrate removal. The consortium co nsists o f various forms of denitrifying species of microbes. The microbes are initially inoculated in to a media consisting of natural
coconut char as a carbon source. The carbon source and the nitrate contamination serve as the food
source for the microbia l action. Influent water coming from the primary physical chemical treatment
syst em is ideal for processing by such a microbial system.



## ZVI Blue

ZVI Blue TM uses the power of zero valent iron (ZVI) to reduce all forms of selenium to an insoluble
material wh ich remains bound to the reticulated active foam matrix. ZVI creates a shower of electrons which will aggressively reduce selen a te , selen i te and other forms of selenium to a metallic form. ZVI is very effective in reducing selenium through the following mechanism.

## Summary of pilot plant treatment data

Two pilot plants were operated at two different coal burning power plants. One facilit y was treated using a three step treatment train while the other facility was treated using physical/ chemical treatment followed by ZVI Blue TM . Note this second facility did not have nitrate contamination so the use of a biological nitrate removal system w as not required.

Once the treatment systems were optimized

, r esults showed that BOTH facilities were able to meet the proposed effluent guidelines on a consistent basis . Continued testing is designed to show the life cycle of the reactive media and manag ement of effluent over a longer period of time.



## Cost Estimate
Each power plant will require a treatment train specif ically designed to manage its specific water chemistry. Liberty Hydro did provide a detailed cost estimate for a three step treatment trai n for a 350
gpm wastewater system.

The total capital cost for such a system is $45 million which includes a primary physical/chemical treatment step, a simple biological nitrate management step and anchor ZVI technology for metals removal. Operating cost s for the full system is estimated to be $3.5 million annually. This results in a 20 year lifetime cost of $115,000,000 (2014 dollars). This results in a cost of approximately $3 1 per thousand gallon s treated over the 20 year period.

## Conclusion

Treatment of FGD waste waters requires a multi

- step approach to meet proposed effluent guidelines

 Primary physical/chemical treatment

 Biological treatment to manage nitrate

 ZVI Blue anchor technology to remove Selenium, Arsenic and other heavy metals

Cost of treatme nt for a 350 gpm system is estimated to be approximately $30 per thousand gallon s treated

.

Additional testing is required to develop specific treatment options for specific FGD effluent waters . We can provide EPA with additional testing data when available.

The data shows that the three step system outlined above can effectively and economically allow coal burning power plants to meet the proposed ELG’s for selenium.

We look forward to w orking with you to help the industry and the agency meet their goals.

Sincerely

Phil Farina
Executive Sales
419

- 346

- 8848 Phil.farina@libertyhydro.com