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FIELD STUDY-ROS IMPROVES OZONE SYSTEM IN A SURFACE WATER TREATMENT PLANT

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Jenfitch, Inc. based in Walnut Creek, CA has developed a new oxidant that is effective at lowering TOC, reducing THMs and HAA5s, eliminating T & O (taste and odors), effective at controlling HABs (harmful algal blooms), improving coagulation & flocculation, eliminate biofilm formation in the distribution systems, that tell ROS improves ozone system to improve the effectiveness of your primary disinfectant.

Jenfitch’s JC 9465 is one of a series of advanced oxidants using mineral oxychloride technology (MxClyOz) to help improve the removal of pathogens, organic contaminants, and inorganic contaminants. JC 9465 is a new and advanced oxidant that generates reactive oxygen species (ROS) and is NSF Standard 60 approved up to 84 mg/l. ROS are chemically reactive chemical species that contain oxygen (i.e., ozone, singlet oxygen, hydroxyl radical ions, peroxides, and superoxide). The main advantage of using JC 9465 is its ability to generate a high concentration of hydroxyl radical ions initially. Hydroxyl radical ions are extremely reactive, and they react with any molecule in its path, turning that molecule into a free radical and thus propagating a chain reaction. At low concentrations, it can disinfect and eliminate organic and inorganic pathogens in a water treatment system without creating disinfection by-products. In Figure 1, we compare the oxidizing potential of various oxidizing reagents using Electrochemical Potential (Ev):

Oxidizing ReagentEv
Hydroxyl Radical Ion (OH–)2.6-2.8
Mineral Oxychloride (MxOyCLz)2.6-2.8
Ozone (O3)2.04-2.07
Permanganate (MnO4)1.67
Chlorine Gas (Cl2)1.36
Hypochlorous Acid (HOCL)1.49
Chlorine Dioxide (ClO2)0.95

In a study at a 10 mgd water treatment facility in Northern California that was using ozone in front of their filters, we achieved the following results in a 90-day study using a dosage rate of 8-10 mg/l of JC 9465 as a pre-oxidant:

ParametersBeforeAfter Using JC 9465% Improvement
Raw Water Turbidity (NTU)2.32.1 
Settled Water Turbidity (NTU)0.700.21+70.0%
Raw Water-NOM0.1580.115 
Filtered Water NOM0.0440.017+61.4%
Raw Water (TOC)4.63.7 
Filtered Water TOC2.21.1+50.0%
Raw Water Bromide (µ/𝑙)300300 
Filtered Water Bromate (µ/l)8.41.7+79.8%
Filtered Water TTHM’s (µ/l)20.08.7+56.5%
Filtered Water HAA5’s (µ/l)6.00100.0%+
T & O Complaints (Aug)15+0 

The Plant Manager for the City of Martinez, Mr. Chris Kania, wanted to see if the new mineral oxychloride, JC 9465, could help reduce the ozone demand at his water treatment plant. His ozone system was over 20 years in service and needed to be replaced and the City of Martinez was in the design stages of replacing the system. He initially dosed the raw water influent with 0.5 mg/l of 12.5% sodium hypochlorite in the hope that it would allow him to operate ozone generators at 60-70% of rated capacity. This did not work. Next, Mr. Kania started feeding JC 9465 at 10 mg/l into the raw water inlet and immediately had to turn the ozone generator down to 40% of rated capacity. At this new feed rate for the ozone generators, he was able to maintain a 0.20 mg/l to 0.30 mg/l ozone residual at a rated flow rate of 10 mgd and lower energy consumption by 50-60%.

Enhanced Coagulation

After several days of running JC 9465, plant operators noticed pin floc carrying over into the filter basis. The plant was fed 35 mg/l of alum (dry basis) and 1.4 mg/l of a 20% polydadmac.  The Plant Manager contacted a chemical vendor to evaluate several different coagulants and flocculants. The results of the study were: 1) change from 47.5% alum to 5% acidified alum and 2) change from a 20% polydadmac coagulant to an ACH/polymer blend, JC 1670.

The results from changing the organic and inorganic coagulant were: 1) better control of pH in the Settling Basin (6.8-6.9), 2) Settled Water turbidity went from 0.70 NTU to 0.21 NTU, 3) Filtered Water Turbidity went from 0.06 NTU to 0.02 NTU, 4) Filtered Water TOC went from 2.2 mg/l to 1.1 mg/l and 5) Dissolved Organic Carbon went from 2.2 mg/l to 1.1 mg/l.

Lowering Bromate in Ozone System

Prior to starting the plant trial with JC 9465, the monthly results for bromate was 18 µl/l. The State and Federal limits were 10µl/l or less. The ozone system was over 20 years+ and needed replacement or upgrading. Estimated cost ranged from$10MM to over $50MM.

The plant operating goal for the ozone generators was to maintain a 0.20 mg/l to 0.30 mg/l residual. To achieve this goal at a flow rate 10 mgd, the ozone generators

had to be operated at over 110%+ rated capacity. Because of the high concentration of bromide in their source water (+300µl/l), they had the potential to convert bromide to bromate.

The plant started feeding JC 9465 at 10 mg/l in front of the flash mixer. Within an hour, the ozone generators were being operated at less than 40% of rated capacity. The plant observed an immediate reduction in energy consumption. Chlorine consumption was reduced by 40% going to the clear well.

In the following monthly testing, the bromate residual was less than 1.0 µl/l during the entire study.

Conclusion

By feeding JC 9465 at 10 mg/l into the flash mixer, we observed an improvement in water quality going to the distribution system. The plant operators noticed a reduction in T & O (taste and odor) complaints (Previous Year-over 15+ and during the study-none).

Biofilm and algae growth in the clarifiers and weirs was eliminated. The particle density and clarity in the Sed Basin improved.

Sludge from the Sed Basin was easier to dewater with the existing system.

Reduction of Disinfection By-Products in the clearwell. The effluent from the plant went from 20µl/l

(TTHM’s) to less than 8.7µl/l (TTHM’s) and 6.0µl/l (HAA5’s) to-non detect.

Using JC 9465, we achieved a 70% removal of TOC vs 52% (current). This indicates removal of more dissolved organic carbon and improvement in coagulation. This is what has been observed using ozone as a pre-treatment.

JC 9465 is a new mineral oxychloride chemistry is that designed to help bring water and wastewater treatment plants into the 21st Century. It is NSF Std 60 certified and USEPA FIFRA registered as a primary disinfectant.

For more information and samples, please email charles@jenfitch.com or visit www.jenfitch.com

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Hydroxyl Radical eliminates H2S in Wet Scrubbers & Flue Gases

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In a recent study in Houston, TX, H2S was removed from a natural gas stream containing 2,000 mg/l of H2S and 5% CO2 using JC 9465 ROS. JC 9465 ROS is a new mineral oxychloride compound that generates Reactive Oxygen Species (ROS) like hydroxyl radical ions and other ions in a highly soluble form that is easy to use. The study, which simulated the operating conditions of a wet scrubber, found that the high concentration of soluble hydroxyl radical ions quickly took the ORP (oxidation-reduction potential as measured by mV) from -150 mV to +100 mV, completely eliminating the H2S. The residual materials left in the solution were inert sulfate compounds.

Sour gas and sour water are terms used to describe gas and water containing significant amounts of hydrogen sulfide (H2S). Sour water and sour gas applications are abundant at oil refineries and natural gas plants. The “sweetening” of gas and water refers to the processes used to remove H2S and organosulfide compounds. Hydrodesulfurization is a method used to remove sulfur in these applications. It is a catalytic chemical process used to capture the sulfides in natural gas and refined petroleum products including gasoline, jet fuel, kerosene, fuel oils and diesel fuel. The H2S gas is subsequently converted into elemental sulfur with the Claus Process.

One of the reasons that it is important to remove sulfides from natural gas and refined petroleum products is to reduce the sulfur dioxide emitted when the fuel is combusted in automobile engines, power plants and furnaces. The U.S. Environmental Protection Agency (EPA) has focused on SO2 as a pollutant for decades. The largest sources of SO2 emissions are from fossil fuel combustion at power plants (73%) and other industrial facilities (20%). In 2010, the U.S. EPA revised the primary SO2 National Ambient Air Quality Standards (NAAQS) by establishing a new one-hour standard at a level of 75 ppb. The EPA revoked the two existing primary standards because they would not provide additional public health protection given a one-hour standard at 75 ppb.

According to the U.S. EPA, current scientific evidence links short-term SO2 exposures, ranging from 5 minutes to 24 hours, with an array of adverse respiratory effects, including bronchial constriction and increased asthma symptoms. These effects are particularly important for asthmatics at elevated ventilation rates (e.g. while exercising or playing). Studies also show a connection between short-term SO2 exposure and increased visits to emergency departments and hospital admissions for respiratory illnesses, particularly in at-risk populations such as children, the elderly, and asthmatics.

Wet scrubbing is one of the processes used to remove Nitrogen compounds (NOx) and Sulfur compounds (SOx). During this process, particulates and pollutants are removed from a gas or liquid stream through contact with a scrubbing liquid. The scrubbing liquid is typically a water-based solution that is recirculated through a sprayer at the top of a tower, with the gas stream moving up the tower from the bottom. This countercurrent flow is used to efficiently capture particulate matter and absorb specific chemicals from the gas. Acidic solutions (sulfuric acid solutions) absorb alkaline gases such as ammonia, and alkaline solutions (caustic soda, sodium hypochlorite, lime slurry) absorb acidic gases such as sulfur dioxide, carbon dioxide, and hydrogen sulfide. The goal of this treatment is to keep hydrogen sulfide below 4 mg/l. In the area of non-regenerative systems, there are four types of chemical scavengers: aldehyde-based, metallic oxide-based, caustic-based, and other processes (oxidants).

The Problem

There are many types of chemical scavengers available to use in a wet scrubber scheme. However, there are several criteria for gas and liquid treatments: 1) rapid rate of reaction, 2) non-reversible reaction path (no reversion to H2S), 3) cost efficiency per mole of H2S removed, and 4) prevention of solids formation (e.g. dithiazine).

The Solutions – Hydroxyl Radical Ions

A variety of chemical oxidizers have been used in wet scrubbers for the removal of hydrogen sulfide. How quickly and efficiently the hydrogen sulfide is oxidized is directly proportional to the oxidant’s oxidation potential. The contact time for hydrogen sulfide to react is inversely proportional to the oxidation potential of the chemical used as the oxidizer. (Note that the higher the oxidation potential, the quicker the reaction.)

Oxidation Potential of Various Oxidizers

OxidizerFormulaOxidation Potential
FluorineNF33.0
Hydroxyl RadicalOH–2.8
OzoneO32.1
Hydrogen PeroxideH2O21.8
Potassium PermanganateKMnO41.7
Chlorine DioxideClO21.5
ChlorineCl21.4
OxygenO21.2
HypochloriteOCl0.9

JC 9465 ROS generates hydroxyl radical ions which are one of several reactive oxygen species (ROS) that meets the above criteria. It is a new low-cost technology that is easy to use in a variety of applications and systems. It will oxidize sulfur compounds to sulfur oxide or elemental sulfur. By using a simple tool, the ORP meter, and controlling treatment dosage between +100 mV to +300 mV, we eliminate H2S. JC 9465 ROS reacts quickly and will not permit reversion back to H2S or form precipitants. (Note that JC 9465 will generate elemental sulfur

[S0] if the ORP is run above +700 mV.)

The capital cost to set up a system to feed JC 9465 is low. The chemical feed system is simply a metering pump and a chemical storage tank. For a fully- automated system, you would need to install an ORP controller on the return line or in the sump. The ORP controller can be used to monitor the millivolts (mV) and control chemical dosing of JC 9465.

Below is a cost comparison of several treatment systems:

Odor Control Technologies Cost Comparison

Technology (Max H2S Conc.)Capital Cost YR 2009Annual O&M YR 2009Cost per lb. of H2S Removed
Chemical Scrubber (100 ppm)*$206,000$148,000$3.50
Bio-Scrubber (100 ppm)*$383,000$10,200$0.24
Bio-Filter (5 ppm)*$355,000$65,000$30.62
Std. Carbon Scrubber (5 ppm)*$100,000$315,000$148.41
Catalytic Carbon Scrubber (5 ppm)*$140,000$30,100$14.18
JC 9465 ROS(2,000 ppm)**$10,000$4,700$0.0040
Triazine (2,000 ppm)*$300,000$30,000$0.0132

All technologies are rated at 10,000 cfm or 75,000 lbs of air per day with 200 ppm of H2S

* Rated maximum removal rate

** JC 9450 ROS has no limit on the amount of H2S removal

The graph of JC 9465 at 3% demonstrates that 1 mg/l of JC 9465 is required to remove 2.0 mg/l of H2S (by weight). The graph demonstrates that by continuously feeding JC 9465 and maintaining a control range of

+100 mV to +300 mV, the system could achieve optimum H2S removal while being cost effective.

Conclusion

Wet scrubbing can be a cost-effective treatment in a non-regenerative application using JC 9465 as a primary oxidant. JC 9465 is easy to feed and simple to monitor. It is a low-technology solution for removing hydrogen sulfide and carbon dioxide. JC 9465 can be used to treat natural gas, crude oil, refined petroleum products, anaerobic digester gases, flue gases, and others. It is safe to use – non-flammable and non-combustible. It is a part of the new green technology for a safer environment for all.

If you would like more information about JC 9465 and related technology, please contact Jenfitch, Inc. at 925-289-3559.