Pulsed Corona Discharge Sterilization (PCDS): Advanced Water Disinfection Without Altering Chemical Composition

Pulsed Corona Discharge Sterilization (PCDS) is an innovative water treatment technology designed specifically for deep plasma sterilization while preserving the inherent chemical makeup of water. Operating under principles similar to other plasma-based methods such as PCDR and PCDO, PCDS differentiates itself by igniting the discharge in a nitrogen atmosphere, or nitrogen with a slight admixture of oxygen. This unique operating environment plays a crucial role in the mechanism of sterilization.
Additionally, PCDS offers significant advantages over traditional ultraviolet disinfection, which often struggles with turbid or highly colored water. The innovative plasma process generates reactive species that effectively neutralize pathogens even in water containing high levels of suspended solids and color, ensuring robust disinfection without the need for pre-treatment. This results in improved operational efficiency and broader applicability across various water treatment scenarios.

In the PCDS process, the discharge triggers the homolytic dissociation of water molecules, resulting in the formation of hydroxyl (OH) radicals and atomic hydrogen.The reaction is initiated by the energy provided from the pulsed corona discharge, which efficiently cleaves the water molecules into these reactive species. However, unlike other oxidation processes, the environment in PCDS is maintained such that there is an absence of significant scavengers for atomic hydrogen. As a result, the medium does not become strongly oxidative. This controlled reaction environment ensures that the process achieves deep sterilization without introducing excessive chemical changes to the water.

The primary benefit of PCDS lies in its exceptional ability to inactivate a wide spectrum of microbial contaminants. The reactive species generated during the process—particularly the OH radicals combined with the unscavenged atomic hydrogen—are highly effective at destroying bacteria, viruses, fungi, protozoa, and even the most resilient spores. By targeting these pathogens at a molecular level, PCDS ensures that water is thoroughly sterilized, making it safe for various applications, including potable water treatment,wastewater reuse, and other sensitive industrial processes.

In contrast to conventional ultraviolet (UV) disinfection—which is significantly hindered by high color of water, turbidity and presence of some UV-absorbing organic compounds, — PCDS maintains its sterilization efficacy regardless of adverse water conditions. The pulsed corona discharge method generates potent reactive species that remain effective even in raw, untreated wastewater. This resilience enables direct disinfection without the need for extensive pre-treatment, ensuring consistent microbial control despite challenging wastewater composition.

A key advantage of this method is that, while it provides robust sterilization, it does so with minimal alteration to the water’s chemical composition. In contrast to other oxidative methods, PCDS does not lead to the formation of nitrates or significant changes in the water’s inherent properties. This makes it particularly attractive in scenarios where maintaining the original water chemistry is critical. For instance, if the objective is solely to achieve disinfection without affecting parameters like pH, TOC and COD, PCDS stands out as the preferred technology.

It is important to note, however, that if water treatment requirements extend beyond sterilization—for example, when there is a simultaneous need to reduce chemical oxygen demand (COD), total organic carbon (TOC), and to oxidize refractory organic compounds—the PCDO technology is the better choice. PCDO not only disinfects but also provides oxidative degradation of tough contaminants, albeit at a lower energy consumption of approximately 0.15 kWh per cubic meter in the sterilization mode. In contrast, PCDS is dedicated solely to the sterilization process and typically incurs higher energy costs, starting at around 0.25 kWh per cubic meter, due to the specific energy requirements of its non-oxidative plasma chemistry.

In summary, Pulsed Corona Discharge Sterilization (PCDS) is a highly specialized technology engineered for the deep, non-oxidative sterilization of water. Its ability to generate effective disinfecting agents without altering water chemistry makes it ideal for applications where water quality must be preserved. By ensuring the complete inactivation of pathogens without the side effects of nitrate formation or chemical imbalance, PCDS represents a significant advancement in plasma-based water treatment solutions, delivering both safety and quality in a single, efficient process.

Overview of PCDS Technology

  • Pulsed Corona Discharge Sterilization (PCDS) is an innovative water treatment technology specifically engineered for deep plasma sterilization while preserving the inherent chemical composition of water.

  • The method is designed to achieve a high degree of microbial deactivation with minimal impact on water’s physicochemical parameters.

Fundamental Operating Principles

  • PCDS is based on pulsed corona discharge techniques similar to those used in PCDR and PCDO, our chemical plasma treatment methods.

  • The discharge is ignited in an atmosphere primarily composed of nitrogen, often with a slight admixture of oxygen, which allows to achieve deep sterilization without noticeable changes in the chemical composition of water.

Mechanism of Chemical
Processes

  • This mechanism ensures the effective inactivation of a wide spectrum of pathogens, including bacteria, viruses, fungi, protozoa, and even resilient spore-forming organisms. The molecular-level targeting of pathogens results in thorough sterilization, making the treated water suitable for potable water supply, wastewater reuse, greenhouses water feeding, sterilization of biologically hazardous wastewaters, and other sensitive industrial applications.

  • Furthermore, the non-thermal plasma process minimizes chemical residues, ensuring an eco-friendly operation. This energy-efficient method reliably disrupts microbial cell structures and genetic material, reducing pathogen reactivation risk and proving optimal for diverse applications and safe performance.

Antimicrobial Efficacy and Spectrum

  • The reactive species generated—particularly the hydroxyl radicals combined with unscavenged atomic hydrogen—exhibit potent antimicrobial activity.

  • This mechanism ensures the effective inactivation of a wide spectrum of pathogens, including bacteria, viruses, fungi, protozoa, and even resilient spore-forming organisms.

  • The molecular-level targeting of pathogens results in thorough sterilization, making the treated water suitable for potable water supply, wastewater reuse, greenhouses water feeding, sterilization of biologically hazardous wastewaters, and other sensitive industrial applications.

Preservation of Water’s Chemical Composition

  • This mechanism ensures the effective inactivation of a wide spectrum of pathogens, including bacteria, viruses, fungi, protozoa, and even resilient spore-forming organisms. The molecular-level targeting of pathogens results in thorough sterilization, making the treated water suitable for potable water supply, wastewater reuse, greenhouses water feeding, sterilization of biologically hazardous wastewaters, and other sensitive industrial applications.

  • Moreover, its advanced design ensures seamless integration into existing treatment systems with minimal modifications, offering affordable scalable solution for water purification.

Comparison with
PCDO Technology

  • While PCDO technology not only disinfects but also facilitates the oxidative degradation of refractory organic compounds, thereby reducing COD and TOC, it is used in scenarios requiring comprehensive water treatment.

  • PCDO operates at a lower energy consumption (approximately 0.15 kWh per cubic meter in sterilization mode) compared to PCDS.

  • PCDS, dedicated solely to non-oxidative sterilization, typically incurs higher energy costs (starting at around 0.25 kWh per cubic meter) due to its specific energy requirements for maintaining non-oxidative plasma chemistry.

Eliminating Waterborne Pathogens: A Comprehensive Approach to
Water Safety

Water contamination poses a significant public health threat. PCDS is designed to eliminate a broad spectrum of bacteria, viruses, protozoa, fungi, and multicellular parasites, ensuring water safety even under the most challenging conditions.

Below, we classify these microorganisms based on their health risks and resistance to conventional water treatment methods.

Pathogens Responsible for Waterborne
Disease Outbreaks

Microorganisms frequently found in contaminated drinking water and wastewater,
leading to epidemic outbreaks and serious health concerns.

Bacteria

  • Escherichia coli (EHEC, ETEC, EPEC, etc.) – Causes diarrhea, hemolytic uremic syndrome, and severe gastrointestinal infections.

  • Vibrio cholerae – The causative agent of cholera, a life-threatening diarrheal disease.

  • Salmonella spp. – Responsible for typhoid fever, paratyphoid fever, and gastroenteritis.

  • Shigella spp. – Causes bacterial dysentery, leading to severe diarrhea and dehydration.

  • Campylobacter jejuni – A leading cause of bacterial gastroenteritis worldwide.

  • Pseudomonas aeruginosa – Associated with wound infections, pneumonia, and urinary tract infections.

  • Yersinia enterocolitica – Causes foodborne and waterborne gastroenteritis and pseudoappendicitis.

Viruses:

  • Rotavirus, Norovirus, Astrovirus – Highly contagious viruses causing severe gastroenteritis, particularly in children.

    Hepatitis A, Hepatitis E – Waterborne viruses affecting the liver, leading to acute hepatitis.

    Enteroviruses (Poliovirus, Coxsackievirus, Echovirus, etc.) – Causes poliomyelitis, meningitis, myocarditis, and encephalitis.

    Adenoviruses – Various serotypes responsible for gastrointestinal, respiratory, and eye infections.

Multicellular Parasites:

  • Schistosoma spp. – Blood flukes responsible for schistosomiasis, affecting the liver and urinary tract.

  • Fasciola hepatica – The liver fluke, causing fascioliasis.

  • Strongyloides stercoralis – A parasitic nematode leading to chronic gastrointestinal and systemic infections.

  • Dracunculus medinensis – The Guinea worm, transmitted through contaminated water.

Protozoa:

  • Giardia lamblia – Causes giardiasis, leading to chronic gastrointestinal issues.

  • Cryptosporidium parvum – Highly resistant to chlorine disinfection, causes severe diarrhea.

  • Entamoeba histolytica – The causative agent of amoebic dysentery and liver abscesses.

…and many more.

Pathogens Resistant to Conventional
Water Treatment

Microorganisms that survive standard disinfection methods, such as chlorination
and boiling, requiring advanced treatment solutions.

Bacteria:

  • Mycobacterium avium complex (MAC) – Atypical mycobacteria highly resistant to chlorination.

  • Legionella pneumophila – Thrives in water systems and causes Legionnaires’ disease.

  • Helicobacter pylori – A major cause of gastric ulcers, transmitted via contaminated water.

Protozoa

  • Cryptosporidium parvum – Oocysts are highly resistant to chlorination and UV treatment.

  • Acanthamoeba spp. – Free-living amoebas that cause severe eye infections and encephalitis.

  • Naegleria fowleri – A rare but deadly brain-eating amoeba found in warm freshwater.

Spore-Forming Bacteria:

  • Clostridium botulinum – Produces botulinum toxin, one of the most potent neurotoxins known.

  • Clostridium difficile – Causes severe antibiotic-resistant infections.

  • Bacillus cereus – A heat-resistant bacterium responsible for food poisoning.

Viruses

  • Adenoviruses (resistant serotypes) – Can persist in treated water and infect various organs.

  • Hepatitis E virus – Resistant to common disinfection processes.

  • Norovirus – Extremely resilient, spreading through contaminated water and surfaces.

Plant Viruses

While plant viruses do not directly infect humans, their presence in irrigation and drinking water can impact agriculture and food security.

  • Tobacco mosaic virus (TMV) – One of the most resilient plant viruses, can persist in water and soil for long periods.

  • Tomato spotted wilt virus (TSWV) – Transmitted via contaminated water, affecting crops.

  • Potato virus Y (PVY) – Affects solanaceous crops and spreads through irrigation systems.

  • Cucumber mosaic virus (CMV) – Highly transmissible in water, affecting a wide range of plants.

  • Barley yellow dwarf virus (BYDV) – Waterborne transmission plays a role in agricultural outbreaks.

Why Plant Viruses Matter:

  • Although plant viruses do not cause human disease, they can spread through irrigation systems and contaminated water, leading to massive agricultural losses and food insecurity.

  • Advanced water treatment solutions can help prevent the spread of plant pathogens and protect agricultural resources.

…and many more.

High-Risk Biological Agents (Bioterrorism,
Laboratory Accidents, Hospital Waste)

Pathogens classified as biological hazards due to their potential for mass outbreaks,
bioterrorism, and accidental environmental contamination.

Bacteria

  • Bacillus anthracis – The causative agent of anthrax, capable of surviving in water for decades.

  • Yersinia pestis – The plague bacterium, potentially transmissible through contaminated water.
    Francisella tularensis – Causes tularemia, a highly infectious disease.

  • Brucella spp. – The causative agent of brucellosis, transmitted through contaminated dairy products and water.

  • Leptospira spp. – Causes leptospirosis, commonly spread through rodent-contaminated water.

Spore-Forming Bacteria:

  • Clostridium botulinum – Produces botulinum toxin, a potential bioterrorism agent.

  • Clostridium perfringens – Spores can persist in water supplies, producing harmful toxins.

Protozoa & Parasites:

  • Trypanosoma cruzi – The causative agent of Chagas disease, potentially waterborne.

  • Paragonimus westermani – A lung fluke causing chronic parasitic infections.

  • Dracunculus medinensis – Once widespread, now a near-eradicated waterborne parasite.

Viruses

  • Ebola virus, Marburg virus – Highly lethal hemorrhagic fevers with potential for waterborne spread.

  • Variola virus (Smallpox) – Eradicated but remains a bioterrorism concern.

  • Nipah virus, Hendra virus – Zoonotic viruses with high mortality rates.

…and many more.

Conclusions and Technological
Significance

  • PCDS represents a highly specialized approach for deep, non-oxidative water sterilization, ensuring complete inactivation of pathogens without disrupting the chemical balance of the water while maintaining its original composition, preventing harmful by-products, and preserving overall water quality.
  • The technology is particularly valuable in applications where preserving the original water quality is critical, and it offers a significant advancement in plasma-based water treatment by combining safety with high sterilization efficacy.
  • Overall, PCDS exemplifies a breakthrough in water treatment solutions, delivering both exceptional microbial decontamination and the maintenance of water’s intrinsic chemical properties.
  • PCDS provides reliable protection against a wide range of microorganisms, including bacteria, viruses, protozoa, fungi, and parasites that pose significant epidemiological risks. Unlike traditional water treatment methods, PCDS effectively inactivates even spore-forming and toxin-producing pathogens, preventing their adaptation and survival.