Non-Thermal Plasma for Chemical-Free Water Treatment
Lead Research Organisation:
Swansea University
Department Name: College of Engineering
Abstract
Before water reaches the tap, it must go through a range of treatment steps to make it wholesome and fit for human consumption. This involves the usage of large amounts of chemicals to remove dissolved and suspended contaminants and disinfection of the water. One of the important characteristics of water that has significant effect on the effectiveness of the treatment process is pH (a measure of the acidity of water). This parameter is so important to the point that if it is not properly controlled within a certain range, the treatment process fails. pH control is required for example during water clarification and disinfection and also during removal of phosphorus or heavy metals in wastewater. The requirement for pH control during water and wastewater processing is wide and touches almost all steps in the treatment process. However, accurate control of pH requires the use of a significant amount of chemicals such as lime, caustic soda, hydrochloric acid, and sulphuric acid. Until now, addition of chemicals to control the pH is the "norm" and this practice has not been challenged or disrupted. With increasing pressure on natural resources and stringent environmental and safety legislations, there is a need for new sustainable processes to reduce the use of chemicals and the associated carbon footprint with their transportation. With this in mind, radical thinking in this ignored area is required.
A new sustainable and innovative approach for pH control is the subject of this proposal. The basic concept of the new idea is that when water is exposed to plasma, its pH changes to either acidic or alkaline values. This project will use this concept to develop a new sustainable method for the control of pH in water and wastewater treatment processes and this technique is expected to lead to a chemical-free treatment method with a range of additional benefits.
Plasma plays an important role in a wide variety of industrial applications such as material processing and semiconductor manufacturing. More recently, interest has increased significantly in liquid plasma discharge as an alternative to conventional water treatment techniques. Out of the types of plasmas, non-thermal plasma (NTP) is of interest since the power used is mainly to generate the plasma without heating the bulk volume. NTP is produced by a high voltage discharge between two electrodes where a large amount of high energetic electrons, various reactive molecular and radical species, ions and photons are generated (e.g. OH-radicals, ozone, hydrogen peroxide, UV, shock waves). When water is exposed to this highly reactive environment, a range of useful chemistries for the oxidation of contaminants and disinfection of water resulting from the synergetic effects of these take place. Removal of contaminants in water has been the main focus of research carried out on plasma application in water treatment so far. However, when applied to water, NTP does not only produce oxidants and disinfectants, but also it has potential to change the pH of the water hence it can be used as a method to control pH in water. The primary focus of this research is to determine the optimal conditions for controlling pH in water under conditions similar to those expected in a real treatment process. This will involve the design and fabrication of three plasma prototypes with different electrode configurations, then determine the most effective NTP operating conditions that enables production of water at a given alkaline and acidic pH set values. The system will then be tested using real drinking waters and real wastewaters. The project will also provide an appreciation of the additional benefits that the system is expected to offer such as removal of pesticides, metals and endocrine disrupting chemicals and based on the outcomes of this study, the key issues that will determine the commercial potential of NTP for pH control will be defined.
A new sustainable and innovative approach for pH control is the subject of this proposal. The basic concept of the new idea is that when water is exposed to plasma, its pH changes to either acidic or alkaline values. This project will use this concept to develop a new sustainable method for the control of pH in water and wastewater treatment processes and this technique is expected to lead to a chemical-free treatment method with a range of additional benefits.
Plasma plays an important role in a wide variety of industrial applications such as material processing and semiconductor manufacturing. More recently, interest has increased significantly in liquid plasma discharge as an alternative to conventional water treatment techniques. Out of the types of plasmas, non-thermal plasma (NTP) is of interest since the power used is mainly to generate the plasma without heating the bulk volume. NTP is produced by a high voltage discharge between two electrodes where a large amount of high energetic electrons, various reactive molecular and radical species, ions and photons are generated (e.g. OH-radicals, ozone, hydrogen peroxide, UV, shock waves). When water is exposed to this highly reactive environment, a range of useful chemistries for the oxidation of contaminants and disinfection of water resulting from the synergetic effects of these take place. Removal of contaminants in water has been the main focus of research carried out on plasma application in water treatment so far. However, when applied to water, NTP does not only produce oxidants and disinfectants, but also it has potential to change the pH of the water hence it can be used as a method to control pH in water. The primary focus of this research is to determine the optimal conditions for controlling pH in water under conditions similar to those expected in a real treatment process. This will involve the design and fabrication of three plasma prototypes with different electrode configurations, then determine the most effective NTP operating conditions that enables production of water at a given alkaline and acidic pH set values. The system will then be tested using real drinking waters and real wastewaters. The project will also provide an appreciation of the additional benefits that the system is expected to offer such as removal of pesticides, metals and endocrine disrupting chemicals and based on the outcomes of this study, the key issues that will determine the commercial potential of NTP for pH control will be defined.
Planned Impact
Large volumes of chemicals such as lime, caustic soda, and acids are traditionally used to control the pH of water and wastewater to adequate values required in the treatment process. This practice has not been changed or challenged since its first use but with the increasing demand for natural resources, which are finite, increasing costs, and stringent environmental and safety regulations there is a need for alternative methods. The technology proposed in this proposal is unconventional and is expected to disrupt the methods currently used by water utilities to control the pH of the water and wastewater they process. The longer term aim of this research is to provide an effective sustainable technology for pH control in water which is expected to provide additional benefits in the treatment process such as removal of metals and water contaminants as well as water disinfection. So far there has been little attention to this area of the treatment process despite the significant amounts of chemicals used for pH control, which are in most cases transported to the treatment site. Transport and use of resources is unsustainable and the proposed method avoids both. The proposed method will develop into a major integral unit operation in the water and wastewater treatment processes. The work proposed in this proposal will lead to a commercially valuable and transformative technology suitable for implementation world-wide. The outcome of this research will benefit the UK economy as well as enhance its position in innovation in the water sector. The main beneficiary of this technology will be the water industry that will benefit a sustainable pH control technique offering no purchase and storage of chemicals, safer operating sites since there will be no handling of chemicals for pH control, reduction of impact on the environment, reduction in sludge volumes due to reduction in chemical use, reduction of the environmental impact resulting from the haulage of chemicals to the treatment sites, and reduction of the water microbial and contaminant loads. The latter benefit also leads to reductions in other chemicals used for disinfection and oxidation purposes (e.g. chlorine and ozone) as well as potential for the reduction of disinfection by-products. These together could lead to enormous cost savings on water and wastewater processing beneficial to industry and customers. The proposed technology would have a vast international market not only in the water sector but also other industries and niche areas requiring pH control would also benefit from the proposed technique.
People |
ORCID iD |
Chedly Tizaoui (Principal Investigator) |
Publications
Abdelaziz A
(2018)
Development and characterization of a wire-plate air bubbling plasma for wastewater treatment using nanosecond pulsed high voltage
in Journal of Applied Physics
Farooq S
(2023)
Visible-light induced photocatalytic degradation of estrone (E1) with hexagonal copper selenide nanoflakes in water
in Process Safety and Environmental Protection
Tizaoui C
(2017)
The Water-Food-Energy Nexus: Processes, Technologies and Challenges
Description | We developed a new plasma reactor that facilitates the transfer of plasma into water at low energy. The prototype can be upscaled to treat large volumes of water. We have also developed a new reactor to control water pH. In addition, this award has led to a simpler method to control the transfer of plasma reactive species to water. |
Exploitation Route | We are in the process of filing a patent since the outcomes of the project have the potential for industrial application. This unfortunately has now been delayed due to COVID19. |
Sectors | Agriculture Food and Drink Chemicals Energy Environment Healthcare |
Description | The impact has been delayed not only by COVID-19 but also by a fire incident we had in the building in the summer of 2020. We have started an application for a patent which was reviewed by the patent office but required more data. It was planned to generate such data in 2020 but unfortunately, both the pandemic and the fire incident caused a delay and our labs are still not fully operational to carry out the outstanding experiments. We have just completed extensive work that started last year to generate more data requested for the patent application. We are liaising with the University IP team to progress the patent application this year and develop a commercialisation plan for the technology. This is expected to create economic value and benefit a range of sectors related to agriculture, water, and the environment. |
First Year Of Impact | 2024 |
Sector | Agriculture, Food and Drink,Environment |
Impact Types | Economic |
Description | Active on the Inside: Schools Decontamination amid/post COVID-19 |
Amount | £123,000 (GBP) |
Funding ID | CRISP20-001 |
Organisation | Government of Wales |
Sector | Public |
Country | United Kingdom |
Start | 05/2020 |
End | 03/2021 |
Description | Faculty of Science and Engineering Research Impact Fund |
Amount | £5,000 (GBP) |
Organisation | Swansea University |
Sector | Academic/University |
Country | United Kingdom |
Start | 04/2022 |
End | 07/2022 |
Description | Impact Acceleration Accounts - Research Impact Fund |
Amount | £5,000 (GBP) |
Organisation | Swansea University |
Sector | Academic/University |
Country | United Kingdom |
Start | 02/2016 |
End | 02/2017 |
Description | Non-thermal plasma for direct decomposition of nitrous oxide (Safe and Ethical Disposal of Nitrous Oxide and Entonox Medical Gases) |
Amount | £35,107 (GBP) |
Organisation | Small Business Research Initiative (SBRI) |
Sector | Public |
Country | United Kingdom |
Start | 02/2023 |
End | 03/2023 |
Description | Ozone for rapid sanitising of ambulances and other contaminated environments in response to COVID-19 |
Amount | £150,000 (GBP) |
Funding ID | ACC2014616 |
Organisation | Small Business Research Initiative (SBRI) |
Sector | Public |
Country | United Kingdom |
Start | 03/2020 |
End | 09/2020 |
Description | Plasma applications for smart and sustainable agriculture |
Amount | € 150,000 (EUR) |
Funding ID | CA19110 |
Organisation | European Cooperation in Science and Technology (COST) |
Sector | Public |
Country | Belgium |
Start | 09/2020 |
End | 10/2024 |
Description | Swansea University's EPSRC Research Impact Fund (RIF) Impact Acceleration Account 2022-2025 - Call 3 |
Amount | £30,000 (GBP) |
Organisation | Swansea University |
Sector | Academic/University |
Country | United Kingdom |
Start | 01/2024 |
End | 01/2025 |
Description | Swansea University's EPSRC Research Impact Fund (RIF) Impact Accelerations Account |
Amount | £15,000 (GBP) |
Organisation | Swansea University |
Sector | Academic/University |
Country | United Kingdom |
Start | 03/2023 |
End | 02/2024 |
Title | Characterisation of plasma reactive species in water |
Description | A new method to characterise plasma reactive species produced in water is developed. |
Type Of Material | Technology assay or reagent |
Year Produced | 2019 |
Provided To Others? | No |
Impact | Research groups working on plasma interaction with liquids will benefit from a robust method to measure the plasma reactive species produced in the liquid. Results are yet to be published. Although we planned to complete and publish the results in 2020, the pandemic has delayed access to the lab. As soon as the University started to open in the late summer of 2020, our labs were affected by a fire incident in the roof of the building which resulted in closures and rebuilding of the labs. This is still causing us delays in accessing the experimental and key analytical equipment. |
Description | COST Action: Plasma applications for smart and sustainable agriculture |
Organisation | Institute of Physics |
Country | Serbia |
Sector | Public |
PI Contribution | We contributed to the COST Action proposal "Plasma applications for smart and sustainable agriculture" that was submitted to the European Cooperation in Science and Technology programme. The proposal was successful and the Action has started. Travel restrictions meant that no face-to-face meetings took place but online conferences have been organised instead, to which I presented seminars. |
Collaborator Contribution | Dr Nevena Puac from the Institute of Physics Belgrade has led this proposal. |
Impact | Successful proposal to the EU COST action programme. |
Start Year | 2017 |
Description | Collaboration with University of Pretoria, South Africa ( |
Organisation | University of Pretoria |
Country | South Africa |
Sector | Academic/University |
PI Contribution | Contribution to joint paper drafting and proposal submissions. We are currently collaborating on a project funded by the UK Royal Society, FLAIR scheme, £295k; a proposal I supported but due to the nature of the scheme, funding is only spent in SA. We have also recently submitted a 3-year research proposal to the Water Research Commission in South Africa on Advanced Oxidation Processes for water treatment in rural communities (under review). |
Collaborator Contribution | Contribution to joint paper drafting and proposal submissions. |
Impact | N/A |
Start Year | 2019 |
Description | Non thermal plasma for water decontamination |
Organisation | University of Liverpool |
Department | Department of Electrical Engineering and Electronics |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Sharing knowledge and experiences of non-thermal plasma application in water treatment; PhD examining; and initiation of a research proposal. |
Collaborator Contribution | Sharing knowledge and experiences of non-thermal plasma application in water treatment and initiation of a research proposal. |
Impact | N/A |
Start Year | 2016 |
Description | Visiting Professor at the University of Paul Sabatier Toulouse within the LAPLACE laboratory |
Organisation | Laboratory on Plasma and Conversion of Energy |
Country | France |
Sector | Public |
PI Contribution | Submission of a proposal for a visiting professor to the "Laboratoire Plasma et Conversion d'Energie LAPLACE" Paul Sabatier University Toulouse III. Due to COVID-related travel restrictions, it was not possible to make this visit last year. However, we have applied again for funding this year and the application was successful. A visit to LAPLACE is due to take place this year. |
Collaborator Contribution | Collaboration on the submission of a proposal for a visiting professor to the Paul Sabatier University Toulouse III. |
Impact | This collaboration has resulted in an award to visit the CNRS research centre LAPLACE at Toulouse during the summer of 2021 (pending the restrictions due to Covid19 are lifted). Due to the pandemic, the visit did not take place last year. A further application was made and was successful. The visit is now expected to take place in 2022. |
Start Year | 2020 |
Title | A new plasma reactor for wastewater treatment |
Description | The product we developed is a low-energy plasma reactor that facilitates rapid transfer of the plasma media into water through a bubbling device. |
Type Of Technology | Physical Model/Kit |
Year Produced | 2016 |
Impact | Yet to be defined. |
Description | Advanced oxidation processes including non-thermal plasma for emerging contaminants removal in water. |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Gave a plenary session at the 1st Springer Nature Euro-Mediterranean Conference for Environmental Integration. Sousse, Tunisia (November 2017). |
Year(s) Of Engagement Activity | 2017 |
URL | http://www.emcei.net/index.php?p=program |
Description | Estrone degradation using non-thermal plasma and ozone: kinetics of degradation products |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Oral presentation at the 24th IOA World Congress & Exhibition: Ozone and Advanced Oxidation Leading-edge science and technologies, 20-25 October 2019: Nice, France. The presentation sparked questions and discussions with academics and industrialists around the effects and identification of oxidation products formed in ozone and NTP treatment of water. |
Year(s) Of Engagement Activity | 2019 |
Description | Key note speaker at the Technological Plasma Workshop, Coventry, UK, October 2016. |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | A key note was delivered at the Technological Plasma Workshop, Coventry, UK, October 2016. The talk sparked questions and discussion afterwards from academic colleagues and industrialists. An invitation was made to contribute to future Technological Plasma workshops. |
Year(s) Of Engagement Activity | 2016 |
URL | http://www.tpw-uk.org/ |
Description | Non-thermal plasma for the removal of endocrine disrupting chemicals in water. 15th Technological Plasma Workshop. Coventry, UK (October 2017). |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Gave a talk on Non-thermal plasma for the removal of endocrine disrupting chemicals in water at the 15th Technological Plasma Workshop. Coventry, UK (October 2017). |
Year(s) Of Engagement Activity | 2017 |
URL | http://www.tpw-uk.org/ |
Description | Pivotal technology to combat water contamination |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Professional Practitioners |
Results and Impact | A video and poster were displayed as part of the Swansea University Research Week 2023, which included an Impact Day, to demonstrate the novel plasma reactor developed by the EPSRC/IAA fund. The displayed material sparked interest in the subject. It led to interesting discussions around the impact of the spread of pharmaceuticals and endocrine-disrupting chemicals in the environment and how plasma technology can resolve such a significant problem. |
Year(s) Of Engagement Activity | 2023 |
Description | Seminar at Oxford University on AOPs for EDCs removal |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | 40 UG and PG students and academic colleagues from Oxford University and Spain attended the talk. A lively discussion around AOPs and plasma techniques used to address the issue of endocrine disrupting chemicals found in our waters was made. Potential for collaborations with colleagues at Oxford University and Cordoba University Spain was initiated and a follow up was made. |
Year(s) Of Engagement Activity | 2017 |
Description | Seminar at Swansea University on non-thermal plasma/AOPs for the removal of emerging micropollutants from the water cycle |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Professional Practitioners |
Results and Impact | An audience of PG & UG students and academic colleagues attended the talk, followed by an energetic discussion on the importance of new oxidation-based technologies to address the issue of emerging micropollutants. The audience was also made aware of the problems of micropollutants in the environment and the implication of the suggested solutions to address them. |
Year(s) Of Engagement Activity | 2016 |