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Plasma Electrodynamics Lab

Plasma Electrodynamics Laboratory is a division of the C. & J. Nyheim Plasma Institute focused on:
-investigation of physical phenomena related to hard electron generation in dense gas discharges;
- research of different forms of atmospheric discharges with runaway electrons and their action on gases, liquids, solid surfaces, and biological objects;
- study of synergetic action of atmospheric plasma and nanoparticles (generated in air bubbles inside water) on water pollutants;
- development of effective technologies for deep removing of toxic ions, as well as complex organic and biological pollutants from water.

There is a need to new approaches to solve existing technological problems in biological objects decontamination (liquids, solid surfaces, food, plants, etc. disinfection), as well as in wastewater deep and cost-effective treatment from toxic inorganic pollutant (like heavy metal ions, etc.) and/or high concentrated organics (like landfill leachate) with waste-to-energy conversion. 
Food and agricultural plants disinfection are samples of most actual technologies needed now on the market, where some of new plasma disinfection approaches are looking as very promising. 
Wastewater treatment and waste-to-energy conversion technologies used on the market at present are not effective enough for some of types of wastewater. For example – there are no technologies on the market for dissolved toxic ions (heavy metal ions, arsenic, fluoride, etc.) deep (down to residual concentration on the level of 0.05 mg/l and less) and low-cost (operation cost less than $1/ton) removal from wastewater with chelating agents or with high concentration of some of organics (like in landfill leachate).
Conventional types of atmospheric plasma generated inside or nearby/through the treated water can sometimes results in effective plasma-chemical conversion of different pollutants in water (including pollutant molecules, atoms or ions partial oxidation) by chemical oxidation process or in stimulation of some plasma catalytic processes. But, as a rule, such a pollutant conversion by conventional plasma is not effective enough for highly polluted water deep treatment. 
As a result, there is an actual need for new approaches to solve existing technological problems in wastewater deep and cost-effective treatment from toxic inorganic pollutant (like heavy metal ions, etc.) and/or high concentrated organics (like landfill leachate) with waste-to-energy conversion.

We are investigating the following new approaches:
Approach #1. Some biological objects, heavy hydrocarbons and other organics direct destruction by hard electrons using atmospheric discharge with runaway electrons (ADRE - in corona, DB, or gliding discharge forms);

APPROACH #1. ADRE PLASMA 

Plasma
Discharge with Runaway Electrons in dense gas.
Corona type volumetric discharge. (A. Maltsev, et al. 2001)


Runaway electrons energy distribution in the atmospheric discharge with runaway electrons (ADRE). High voltage pulse generator RADAN – 303, voltage amplitude on the gap is about 150 kV. (Tarasenko, et al, 2009).


Dielectric barrier discharge with runaway electrons. (A. Maltsev, et al, 2014)
 

APPROACH # 1. ADRE PLASMA APPLICATION INVESTIGATION.  

1. Some food and plants disinfection by ADRE of volumetric or gliding forms.
2. Landfill leachate BOD/COD ratio increasing (from 0.1 to 0.3 and higher) by atmospheric discharge of different types (corona, DBD, and gliding DRE, spark in air bubbles inside water) action on leachate.
3. The comparison of heavy hydrocarbons destruction effectiveness by discharges with runaway electrons and by oxidation using hydroxyl radicals. Evaluation of the approach to use any of DRE types for heavy hydrocarbon molecules conversion into syngas.

APPROACH #2. ATMOSPHERIC PLASMA AND NANOPARTICLES GENERATION IN AIR BUBBLES INSIDE WATER 


The picture of atmospheric discharge light emission generated in air bubbles inside water between dispersed conductive load in water reactor. 




Oscillograms of voltage between electrodes of water reactor (kV, solid line) and current (kA, stroked line) at the average power consumption from power supply line 2.4 kW and pulse repetition frequency 700 Hz. (A. Maltsev, 2014). 

APPROACH #2. ATMOSPHERIC PLASMA AND NANOPARTICLES SYNERGETIC ACTION ON POLLUTANT IN WATER

Heavy metal ions removal mechanism investigation from water with chelating agents or high concentration of organic pollution (landfill leachate analogs).
Water sample # 3 (at the left) – initial wastewater with ion concentration [Cr6+] = 49.6 g/m3
Water sample #2 – water # 3 treated by the Approach #2 process (before filtration);
Water sample # 1 (at the right) - water # 2 after filtration. [Cr6+] = 0.01 g/m3
Effectivity of chromium removing is 99.98%.Maximal Permitted Level of [Cr6+] =0.05 g/m3 for water reservoirs of communities. Results by the Approach # 2 application for heavy metal ions removing from wastewater. 

   

Results of the Approach #2 application for heavy metal ions removing from water. 
At the left – Initial wastewater with ion concentration [Cr6+] = 148 g/m3 + [Zn2+] = 417 g/m3  
At the right - Treated wastewater. [Cr6+] = 0.015 g/m3 + [Zn2+] = 0.010 g/m3
Effectivity of Chromium removing is 99.99 %. Maximal Permitted Concentration of [Cr6+] = 0.05 g/m3 for water reservoirs of communities.
Effectivity of Zinc removing is 99.998 %. Maximal Permitted Concentration of [Zn2+] = 1.0 g/m3 for water reservoirs of communities.