Dear Greg,

Indeed, an increasing amount of companies are offering these technologies. In the chemical industry, these processes (e.g. UV/H2O2) are being used to treat toxic and non-biodegradable compounds in wastewater. Often, medim-pressure UV lamps are used to apply direct photolysis in parallel. Also Fenton is used at full-scale there, while it is also used to treat wastewaters with very high COD loads (part of the removal relies on coagulation).

A very recent development (which started 10 years ago) is the application of UV/H2O2 in the drinking water industry. In those cases, a combination of RO and UV/H2O2 is often applied for indirect potable reuse purposes (especially in the US and to a much lower extent in Europe). It is the current state of the art for potable reuse. Also some drinking water companies apply this AOP: often UV is used for disinfection and H2O2 is dosed if taste and odour compounds appear (e.g. during periods of increased algal activity). However, much research work is ongoing with respect to ozonation for water reuse. This is because ozonation is more cost-effective, while having practically the same oxidative power. A few full-scale projects already exist, but much more can be expected once some knowledge gaps are filled (e.g. issues related to byproduct toxicity, bromate formation,...). Ozonation is also gaining interest for tertiary municipal wastewater treatment, as regulations of trace organic compounds are in full development. In parallel, disinfection is applied. The reasen why I am mentioning ozonation here, is that ozonation of municipal wastewater can be designated as an AOP due to a significant HO* production as a result of ozone-based transformation of dissolved organic matter. Hence, a significant fraction of ozone-resistant organics can be removed during ozonation.

Some drinking water companies also use H2O2 in combination with ozonation. However, advanced oxidation is often not the primary goal. Often one wants to restrict bromate formation. It is known that O3 in combination with UV is one of the strongest AOPs, and it has some specific applications (in cases where the oxidative power is beneficial over the energy consumption).

Semiconductor photocatalysts are still in experimental phase (there might be some full-scale reactors using natural sunlight, but this number will be small). A lot of bottlenecks have to be solved first (e.g. restriction of electron-hole recombination, development of catalysts absorbing at higher wavelengths, solving boundary layer issues (hindering diffusion based transfer)...).

Applications of ultrasound also remain limited (ther might be some specific areas where it is applied), mainly due to energy constraints.

To conclude: the interest in AOPs will not stop increasing, mainly due to development of the technology and (new) regulations that will become more stringent.

A list of full-scale ozonation and UV/H2O2 plants for drinking water production and water reuse was presented in my PhD thesis. For your information, I added the link to the document: www.biomath.ugent.be/biomath/biomath_publications.php (the second on the list).

This was only very rough information to give you a first indication, however, I hope this was of help.

Regards,

Wim

Dear Greg,

in my opinion it is quite difficult to answer to your question because the most of full/industrial scale applications are covered by patents and data are not available in scientific literature. Recently I reviewed a "review paper" collecting information on some patents related to AOPs (specifically to heterogeneous photocatalysis applications) but I did not reccomend for publication because any additional data/information compared to the summary of the patents was quoted in the manuscripts (e.g., documented full scale applications). I know just a few applications of solar photocatalysis and solar photo-Fenton processes at full scale I discussed in a book chapter (eventually I can send you a copy), but I do not know any publication where you can find a realistic and updated summary of AOPs applications at full scale

regards

Luigi

I once attended a presentation where the spokesperson told us about a plant where they had a high formaldehyde concentration in their wastewater. The engineering team build a UV treatment unit and they used hydrogen peroxide as a catalyst. The project was successful and the formaldehyde concentration drop way below what was expected.

I am currently looking more into those systems and literature can provide some info about some pilot plants that were built but that's pretty much it. Some industrial installations are using advanced oxidation processes to remove specific contaminants from their wastewater. In those cases, the amount of wastewater treated is often low or the process is efficient for only a certain type of contamination.

HI DEAR Greg Loraine,

MANY REASONS CAN BE INVOLVED, SEE FOLLOWING PAPERS AND YOU CAN UNDERSTAND MORE ABOUT.

Advanced oxidation processes (AOP) for water purification and recovery

http://www.sciencedirect.com/science/article/pii/S0920586199001029

Combination of advanced oxidation processes and biological treatments for wastewater decontamination—a review

Treatment of textile wastewater by advanced oxidation processes—a review

Degradation of Aqueous Pharmaceuticals by Ozonation and Advanced Oxidation Processes: A Review

Degradation of Endocrine Disrupting Chemicals Bisphenol A, Ethinyl Estradiol, and Estradiol during UV Photolysis and Advanced Oxidation Processes

Oxidation of Pharmaceuticals during Ozonation and Advanced Oxidation Processes

Application of advanced oxidation processes for TNT removal: a review

Advanced oxidation processes (AOPs) involving ultrasound for waste water treatment: a review with emphasis on cost estimation

mechanisms for endocrine disrupting compounds (EDCs) in wastewater treatment—physical means, biodegradation, and chemical advanced oxidation: a review

Review of photochemical reaction constants of organic micropollutants required for UV advanced oxidation processes in water

Removal of organic matter from landfill leachate by advanced oxidation processes: a review

Microwaves in advanced oxidation processes for environmental applications. A brief review

Sonophotocatalysis in advanced oxidation process: a short review

Advanced oxidation processes for wastewater treatment: Formation of hydroxyl radical and application

Comparison of advanced oxidation processes for the removal of natural organic matter

Review of ozone for water reuse applications: toxicity, regulations, and trace organic contaminant oxidation

Sulfate radical-advanced oxidation process (SR-AOP) for simultaneous removal of refractory organic contaminants and ammonia in landfill leachate

Progress in membrane separation processes, ozonation and other advanced oxidation processes-A review

Advanced oxidation processes for wastewater treatment: state of the art

Advanced Oxidation Processes (AOPs) for reduction of organic pollutants in landfill leachate: a review

An overview of the integration of advanced oxidation technologies and other processes for water and wastewater treatment

The cost evaluation of advanced oxidation processes in laboratory and pilot-scale experiments

Dear all,

the question from Greg was clear to me: "what extent AOPs have been applied?". He does not looking for scientific publications showing the experimental efficiency of AOPs nor generic information on companies offering these technologies. So if somebody has any data (or knows any paper including data) on the extent of market/commercialization of AOPs it would be really useful...to me too.

thank you in advance

regards

Luigi

Yes, Luigi you are correct I was specifically asking about how often these technologies have been applied. Hooshyar's comment makes my point, although I haven't looked at all of them yet, they are for the most part academic studies, mostly at lab scale. I believe that the strongest potential for AOP systems is for potable water reuse as Wim mentioned in the 1st comment.

Hi, if you are looking for numbers, I only have a more or less exact number for UV/H2O2 applications for drinking water treatment and water reuse (see the link to my PhD above). Like you mentioned: who is installing full-scale plants?-->companies, and not scientists. They do not share data easily, and the problem is that a lot of different companies exist. This is why only for UV/H2O2 for water reuse I was able to more or less collect data for all plants: Trojan has almost a monopoly in that market and almost all applications are posted on their website.

There's a very little chance you find these data in scientific A1 publications (unfortunately!). The most practical scientific A1 journal I know is Ozone:Science and Engineering, which contains some data (off course especially on ozone). I think most valuable sources are: conferences and technical journals such as "IUVA News" and the journal of IOA (you have to be member of those organizations in order to get the information). There, sometimes clear numbers and valuable practical discussions and perspectives are given. (Besides using A1 publications, I alsu used those journals for my literature review, which I think should be done more often; a strong link between science and practice is extremely valuable)

Dear Wim,

I found in your Ph.D. thesis a reference I didn't know (Loeb et al. 2012), I will ask author to send me a copy.

thank you and kind regards

Luigi

Dear Greg! Looking to your affilation, I may speculate that you are interesting in hydrodynamic cavitation ... ??? Me too. But for now this technology is still in experimental lab scale - IMHO it is not (yet) cost effective for large scale ...

Dear Luigi,

the first author is Barry Loeb, editor in chief of O:S&E. He has a lot of practical experience with ozonation. To make it easy, I added the paper as attachment. It is an interesting paper which describes the historical development and current situation very well.

regards,

Wim

Yes Boris, I am involved in hydrodynamic cavitation research and commercialization. I have read some of your papers on the topic. Dynaflow does offer devices for treating water/wastewater by means of HD. I have also been active in other areas of AOP research as well, and I have been interested in the topic for many years.

Dear Wim,

thank you for the manuscript.

regards

Luigi

Dear James,

I found your answer really interesting, particularly in the part of "EEO figure of merit". are you the co-authr of the manuscript quoted in your answer? if so, can you send me a copy of the manuscript?

thank you in adavance

regards

Luigi

I agreed with the answer of Prof. James R Bolton and that of Dr, Wim Audenaert. Many of the AOPs process are applied now for the oxidation and to some extent degradation of organic pollutants found in industrial waste water including dyes and pesticides..

Hello Luigi,

you can find the document you're looking for here:

http://pac.iupac.org/publications/pac/pdf/2001/pdf/7304x0627.pdf

It's a IUPAC Technical Report, so it's freely available on-line.

Regards

Ricardo

A very relevant question indeed. However, no one is mentioning advanced oxidation on BDD anodes... Well, we all know that they are quite expensive, but does it mean that there is still no practical application(s)?

Very interesting discussion.

Could the introduction of UVled reduce the EEO figures for these technologies?

Regards

Jose

in water treatement AOP is applicable to refractory COD

Do you mean water or wastewater? If you talk about refractory COD I can understand you mean industrial wastewater. If so, a lot of studies are avilable in scientific literature about this. For example, AOP (in particular Fenton and photo-Fenton) can be used to improve biodegradability of industrial wastewater (including toxic or refractory compounds) before biological process.

Sorry,yes industrial waste water when a reverse osmosis is installed after the biological treatement

In fact, in every application where a certain amount of organic matter is present, enhanced biodegradability is an issue to consider (and organic matter is always present). During drinking water oxidation, AOC is formed which has to be removed with a BGAC or sand filters. During municipal wastewater treatment plant effluent ozonation, the effluent organic matter (of which an important fraction is natural organic matter) is being transformed into (often toxic) biodegradable fragments. These have to (and can) be removed with a biological post-treatment. Often, also BGAC or sand filtration is used, and more and more the water is being infiltrated into river banks or dunes for indirect (non-)potable reuse.

You might want to refer to BCC Research's study of the global market for UV disinfection equipment through its report "Ultraviolet (UV) Disinfection Equipment: Major Applications and Global Markets". As per the report, this market was valued at $790 million in 2010 and is expected to increase to $1.1 billion in 2013. BCC Research projects the market to reach $2.1 billion in 2018, and register a five-year compound annual growth rate (CAGR) of 13.1% for the period 2013 to 2018.

The report quoted specifically addresses (from the title) UV disinfection. AOPs are quite different processes implementing reagents/chemicals (such as iron and H2O2 in Fenton and photo-Fenton processes, semiconductors (such as TiO2) in heterogeneous photocatalytic process etc.) which strongly affect the cost of the process. But typically UV-C disinfection is basically aimed at bacteria inactivation in water and wastewater, AOPs can cover different applications (industrial wastewater treatment to improve biodegradability, tertiary treatment of urban wastewater, emerigng contaminants removal from water and wastewater, degradation of a wide range of specific contaminants and also disinfection).

Thank you for your comment Luigi. Indeed the report only addresses UV disinfection; nevertheless an indication for the extent and size of applications.

in lab scale UV/H2O2 (Advanced oxidation process) for dye removal. COD of the dye wastewater could not be found as H2O2 and K2Cr2O7 of COD conflict. Although, i am thinking about TOC over COD. My question is can we get H2O2 without stabilizer or how pharma / petrochemical industry check treatment efficiency of their UV/H2O2. Any ideas are welcome.

Ozone and Fenton technology have been used to deal with some industry wastewate

Dear all!

Please find here still "hot" results of our study of diverse AOP treatment processes for municipal wastewater to be used in the textile industry. The article is under review process for being published.

Regards, Boris

Manprett, in relation to your question H2O2 can be also obtained in situ from the reduction of oxygen (eg. ElectroFenton process)...

Regarding Electro-Fenton, do you know industrial applications?

No, I don't know, perhaps because it was patent-protected until a few years ago...

First in what kind of water or waste water do you want to applied the Advanced Oxidation Processes? because there a organic matter that you can oxidize with microorganisms efficiently or are organic matter as the petrochemicals that you need pretreat it and after applied Electro-Fenton, or ozone oxidation, we have been used a biological system (anaerobe-aerobe) and then ozonization and filtration and down the DQO from 40,000.0 ppm to 300 ppm. With a low cost of process (0.090 USD /M3)

It would be useful to the sanitizing action of the electron beam (AOP), with H2O2 as a catalyst to obtain a double quantity of OH radical, for tertiary treatment of large volumes of urban waste water

I think it depends on water and the wastewater quality itself. Here in Malaysia, due to high level of iron, mangan in groundwater some water treatment company prefer to use some advanced oxidation process like using deferum dan demagnum system. This technique involve physical process only and no chemical required thus can considered as environmental friendly. Here ozone sometimes has been use in oxidation process for quick removal of high iron and mangan in water

Mohd, AOPs are usually used for the degradation of organic pollutants in waste water. I would also like to remind you that chemicals used in AOPs are considered as environmentaly friendly...

James, I fully agree with you, but chlorination can not be considered an AOP, right?

Chlorine radicals and OH radicals are not the same.

Right, Collin

Dr Bolton is very experienced in the field and has provided much good information. "Advanced Oxidation" processes are being applied in a few potable reuse projects in the US, toward the end of the treatment train after RO has been applied to reduce most of the residual trace organics and the Total Organic Carbon. Perhaps the principal use is to react with a few refractory organics like 1,4- dioxane, that are not well removed by RO. The process is not very efficient because the OH radicals are not selective to the ppt level trace chemicals of ostensible interest; they are so energetic that they react with just about any organic in the water. So, the TOC should be very low at perhaps a few tenths of a mg/L. It is interesting that Singapore with its long standing NeWater wastewater reuse process does NOT use advanced oxidation, but only UV after RO in its process.

Yes, but the more TOC present the more OH radicals are wasted in extraneous reactions. Of course, a TOC of 1 mg/L (1 ppm) means that there might be a ratio of 100,000 to 1,000,000 to 1 for the few ppt of chemicals of interest that survived the RO.

James, thank you for the useful information! I'm a fan of the physical quantity of electrical energy per order, which you introduced. Yet, recently I have been wondering to which extend it can be considered independent of initial pollutant concentration and there seem to be quite some exceptions. You claim that AOPs are almost always first order and that the first order rate constant is independent of initial concentration below 1mg/L. Can you tell for which AOPs this is definitely the case and for which it is not valid?

To give a counterexample I just found in literature: the rate constant for photocatalytic degradation of methylene blue (UV/ZnO) is obviously not constant for concentrations in the ppm range (so order of magnitude of mg/L). Source:

http://www.banglajol.info/index.php/JCE/article/download/18110/12662

I query whether it would suddenly turn constant below 1 mg/L. I can give other counterexamples, but don't want to overload this post.

James, thanks a lot, that is very helpful! It seems indeed that the other counterexamples I know are dealing with heterogeneity in one way or another . Is your answer about the 1mg/L limit based on own (unpublished) experience or can I find this in literature? Most likely, I will need this very information for one of my next papers.

Application of UV/H2O2 for the purification of  the drinking water  is used industry as a modern technique.

Hi

Please see this paper

http://www.researchgate.net/profile/Ioannis_Poulios/publication/233484930_Advanced_oxidation_processes_for_water_treatment_advances_and_trends_for_RD/links/53e3493b0cf275a5fddad2fc.pdf

Article Advanced Oxidation Processes for Water Treatment: Advances a...

Advanced oxidation is expensive and not necessarily needed for drinking or recycled water  health protection, but there is a somewhat lower cost and more efficient process being applied that uses UV/HOCl rather than UV peroxide to generate the hydroxyl radicals. Los Angeles is building a 12 mgd wastewater recovery plant using that process. They concluded from pilot studies  that capital and operating and lifecycle costs were less than for UV peroxide.  There are  some operational issues to manage, such as that the process is more efficient in the pH range ~ 6.5, and the potential for producing chlorate, perchlorate or bromate should be controlled. LA says they are not a problem. It's worth a good look if AOP is desired.

Advanced oxidation is expensive and not necessarily needed for drinking or recycled water  health protection, but there is a somewhat lower cost and more efficient process being applied that uses UV/HOCl rather than UV peroxide to generate the hydroxyl radicals. Los Angeles is building a 12 mgd wastewater recovery plant using that process. They concluded from pilot studies  that capital and operating and lifecycle costs were less than for UV peroxide.  There are  some operational issues to manage, such as that the process is more efficient in the pH range ~ 6.5, and the potential for producing chlorate, perchlorate or bromate should be controlled. LA says they are not a problem. It's worth a good look if AOP is desired.

i have not yet read the UV/HOCl papers, but wouldn't photolysis of HOCl produce chlorinated free radicals which would increase the AOX concentrations, especially compared to UV/H2O2?

LA did not get much THMs and HAAs in their pilot studies of RO treated Wastewater. It was low TOC water.

LA did not get much THMs and HAAs in their pilot studies of RO treated Wastewater. It was low TOC water.

I have recently made a thorough literature study on advanced oxidation processes with a focus on plasma technology (my field of research). My aim with the study was, amongst others, to get more insight in the possibilities of AOPs for future application in water treatment. In short, it seems unrealistic at the current state of research that advanced treatment methods (this means AOPs, activated carbon and membrane processes) will be applied on a large scale in wastewater treatment plants as an end-of-pipe method. Cost estimation shows that they are too expensive for processing the large volumes of worldwide consumed water. It seems more realistic to reassess existing conventional methods, for example by further optimizing biological treatment. Nevertheless, AOPs still can be applied for small volumes of water. Think: the most important water. Instead of processing all effluent of WWTPs, limiting AOPs to the production of drinking water from this effluent is more realistic. Also, treating hazardous wastewater at the source (hospitals, industry) can significantly reduce the treated volume. Moreover, even if advanced separation techniques such as activated carbon, nanofiltration and reverse osmosis prove to be much cheaper than AOPs, AOPs can still be used for degrading the hazardous concentrates produced by these methods. In the optimistic case that our fellow researchers in the field of plasma fusion are correct, energy costs may not be the main issue in the future. Anyway, as you might already have noticed, there is a lot of speculation on this topic, but very few concrete data.

The manuscript which resulted from my literature study contains more background information, including references to interesting reviews. The manuscript came back from review with positive comments, so it should get published soon. I can upload it on ResearchGate as soon as the publication process is finished. In the meantime, many of you might be interested in this review article which I have encountered during my search:

Michael, I., et al. "Urban wastewater treatment plants as hotspots for the release of antibiotics in the environment: a review." Water research 47.3 (2013): 957-995.

This article mentions a couple of AOPs and refers (somewhat vaguely) to their current application on a larger scale. It mentions, for example, that ultraviolet disinfection is increasingly finding applications in urban WWTPs and that ozonation has been increasingly used for the treatment of wastewater whereas it has been traditionally employed in drinking water treatment. I hope this helps some of you out.

AOP is being used in some large volume wastewater- to- drinking water processes. For example, in Orange County, California, a 100 MGD facility is working very well. It is costly, but less expensive than their alternative sources. Relative cost vs need is the driver.The State of California will probably require AOP for recycled drinking water production. They call it FAT. Full Advanced Treatment.

Thank you Patrick. I believe that another important application for AOPs is the pretreatment of biologically recalcitrant compounds to improve biodegradability. Mirat Gurol did some work in this area about ten years ago for WERF. I also have a paper in that area - 

Article Oxidation of Polyvinylpyrrolidone and an Ethoxylate Surfacta...

Correct. My literature study actually focussed on treatment of micropollution, which is for a very important part caused by bio-recalcitrant compounds. Optimization of conventional biological treatment alone is probably not going to give a satisfactory solution, since such compounds are by definition hard to decompose by means of biological organisms. Many pharmaceuticals are bio-recalcitrant, which explains why the toxicity of hospital effluent is becoming a hot topic. That's what I meant with using AOPs at the source of pollution. There, low volumes with rather high concentration of bio-recalcitrant compounds can be treated as a preparation step. Formed oxidation by-products can be degraded to a greater extent with biological treatment in conventional WWTPs further downstream. But using AOPs directly on all influent of these WWTPs, which have to process large volumes of water from urban, industrial and agricultural sources all together, seems unrealistic, no matter whether it's as an end-op-pipe treatment step or a preparing step before biological (secondary) treatment.

I have less knowledge on application of AOPs for treatment of anorganic or biological wastewater, or very specific wastewater such as dissolved nuclear pollution and nanoparticles, but I know there is a lot of interest in this field as well. Disinfection might be cheapest with chlorine, but with the risk of undesired chlorinated by-product formation. Addition of so-called plasma-activated water is a very new approach which might prove to be a valuable alternative. As said, UV disinfection is increasingly used as well and I'm sure there are many other options to be considered.

Another interesting application  (and not so far away from commercialization in my opinion )  is the electrochemical treatment of ballast water (in situ -ships or ex situ).

The electrochemical treatment of ballast water on ship is to my knowledge just disinfection. Different reactions and formation of short lived oxidants occur around the electrode and there is a residual hypobrome that extends the killing time.

I think it is commercially available already and not unrealistic costly compared to the other ballast water treatment options, but I am not sure it is really AOP.

You'll have to make a distinction between electrochemical separation techniques and electrochemical oxidation techniques.

According to this review, the separation techniques are the most straightforward and cheapest methods for organic pollutant removal:

Sirés, Ignasi, and Enric Brillas. "Remediation of water pollution caused by pharmaceutical residues based on electrochemical separation and degradation technologies: a review." Environment international 40 (2012): 212-229.

According to this review, the oxidation techniques (also in combination with other AOPs) are promising alternatives to other AOPs:

Oturan, Mehmet A., and Jean-Jacques Aaron. "Advanced oxidation processes in water/wastewater treatment: principles and applications. A review." Critical Reviews in Environmental Science and Technology 44.23 (2014): 2577-2641.