Oxidising biocides for industrial use are effective in controlling microbiological activity in:
- commercial cleaning
- environmental hygiene
- disinfection
- industrial and process water treatment activities.
What is oxidizing and non-oxidizing biocide?
What is the Difference Between Oxidising and Non-Oxidising Biocides? Oxidising biocides attack microorganisms by oxidising (an electron transfer reaction) the cell structure, disrupting nutrients from passing across the cell wall. Non-oxidising biocides for industrial use are effective in controlling: Legionella.
Is chlorine an oxidizing biocide?
Types of biocide There are two basic types of biocides: oxidising and non-oxidising. Oxidising biocides include; chlorine, chlorine dioxide, hydrogen peroxide, bromine and ozone.
Why use a non-oxidizing biocide?
When present at a sufficiently high concentration and for a sufficiently long time, non-oxidising biocides kill micro-organisms by interfering with their metabolism, stopping respiration, or lysing the cell walls. As a result, they are often used in open and closed cooling systems.
What is biocide used for in cooling towers?
Routine biocide application is a standard treatment of cooling tower water, to ensure that bacteria are under control and the potential for Legionella is minimized. There are many biocides available, and they can be divided into two categories: oxidizing and non-oxidizing.
Is hydrogen peroxide a biocide?
Hydrogen peroxide is extensively used as a biocide, particularly in applications where its decomposition into non-toxic by-products is important.
Is bleach considered a biocide?
In fact, bleach is considered a biocide because it has properties able to kill bacteria, viruses, and mould.
What is biocide used for?
Biocides are widely used in the food industry as disinfectants and food preservatives. They treat production plants, processing areas and food containers to control the microbial growth in food and drinks.
What are non oxidizing biocides?
Non-oxidizing biocides are anti-bacterial chemicals that use other means of killing bacteria besides oxidizing the electrochemical reaction of the bacteria. These can include combinations of biocides and some dispersants, designed to remove specific bacteria or biofilm.
What is biocide made of?
Many biocides are synthetic, but there are naturally occurring biocides classified as natural biocides, derived from, e.g., bacteria and plants. A biocide can be: A pesticide: this includes fungicides, herbicides, insecticides, algicides, molluscicides, miticides, piscicides, rodenticides, and slimicides.
Why are biocides added to cooling tower water HVAC?
Why Do I Need Biocide In My Cooling Tower? Cooling water provides an ideal environment for biological growth, including Legionella. Because Legionella bacteria can be a health hazard, treating your cooling water properly with the most effective biocide (bacterial disinfectant) is an extremely important task.
What chemicals are used in cooling towers?
Here are the main chemicals that are frequently used in cooling tower water treatment:Corrosion and Scale Inhibitors. ... Algaecides and Biocides. ... pH Adjusters.
What is the best pH level to maintain in a water tower?
between 6.5 and 7.5If you have doubts about the proper pH levels for your tower water, ask your water treatment company for recommendations. A pH between 6.5 and 7.5 is generally considered the ideal range for reducing scale formation, though some non-acid treatments for scale prevention can increase the cooling tower pH range up to 8.5.
What are non oxidizing biocides?
Non-oxidizing biocides are anti-bacterial chemicals that use other means of killing bacteria besides oxidizing the electrochemical reaction of the bacteria. These can include combinations of biocides and some dispersants, designed to remove specific bacteria or biofilm.
What are examples of biocides?
Common examples are disinfectants, wood preservatives and insect repellents. Typically a biocidal product will be a mixture of chemicals and will include the 'active substance'. The active substance has the controlling effect on the harmful organism.
Is sodium hypochlorite a biocide?
Sodium hypochlorite is commonly used as a biocide in industrial applications to control slime and bacteria formation in water systems used at power plants, pulp and paper mills, etc., in solutions typically of 10–15% by weight.
Which one is not the form of biocides?
The correct answer is Bleach.
What biocide is used to kill Legionella?
In today’s heightened awareness and knowledge as it relates to cooling towers and specifically Legionella issues, having a proper biocide in the cooling tower is of the utmost importance. Oxidizing bio cides work by using a halogen (e.g. Chlorine) to “oxidize” the electron transfer in the cell of the bacterium, which will disrupt the cell’s life functions and kill the bacteria. Chardon carries a variety of different oxidizing biocides to protect cooling towers, from sodium hypochlorite to a stabilized bromine product, Chardon has the biocides to help kill bacteria.
Is bromine a biocide?
Revolutionary new biocide that can penetrate biofilm as well as the bacteria itself. This stabilized formula containing both bromine and sodium hypochlorite (chlorine) can be stored for long lengths of time and is much less corrosive than products like bleach. Along with its’ stability, this product becomes a very effective biocide against bacterial growth such as Legionella.
What biocide is used in cooling towers?
Chlorine and bromine are the two most common oxidizing biocides used in cooling tower systems to minimize growth. They each have their strengths. Here’s a quick summary of the pros and cons of each choice from the team at Chemtex.
Is chlorine a biocide?
The active biocidal portion of the chlorine is hypochlorous acid which is a good biocide. But because tower waters often stabilize at a pH near 9.0, considerable amounts of chlorine will need to be added to attain a desired free chlorine residual. Furthermore, if the tower system has a large organic load, it consumes chlorine which demands operators add even more chlorine to maintain a residual. This loading can result from plant processes or from ambient pollen, dust, dirt or even smoke. This additional feed of chlorine needed to overcome the organic loading demand and invites greater potential for corrosion.
What are oxidizing biocides?
Common oxidizing biocides used in industry are chlorine, peracetic acid, sodium bromide, and so on. On the other hand, the nonoxidizing biocides interfere with reproduction, stop the respiration process, or break the cell wall [20]. The kill time of the bacteria can take several hours up to a day.
What is a biocide?
Biocide is a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism by chemical or biological means . Biocides are one of the most commonly used techniques in industry to kill bacteria in the system because of the rapid response. Biocides are divided into two types, oxidizing and nonoxidizing. The oxidizing biocides attack microorganisms by oxidizing (an electron transfer reaction) the cell structure, disrupting nutrients from passing across the cell wall [20]. Common oxidizing biocides used in industry are chlorine, peracetic acid, sodium bromide, and so on. On the other hand, the nonoxidizing biocides interfere with reproduction, stop the respiration process, or break the cell wall [20]. The kill time of the bacteria can take several hours up to a day. Common nonoxidizing biocides used in industry are 1,2-benzisothiazolin-3-on, 5-chloro-2-methyl-4-isothiazolin-3-on, and so on [9,20].
What is biocide silicone?
Biocide-incorporated silicone coatings for antifouling/fouling release applications that involved the biocide Triclosan (5-chloro-2- (2,4-dichlorophenoxy)phenol) were modified with alkenyl moieties and incorporated into a silicone backbone through covalent bonds. The presence of the biocide on the coating surface was expected to deter fouling organisms from attaching to the surface of the coating. Allyl glycidyl ether was used to provide crosslink functionalities. The coatings prepared from biocide-incorporated silicones with the appropriate bulk modulus significantly reduced macrofouling ( Thomas et al., 2004 ).
How do biocide compounds increase antibiotic resistance?
It is not fully known how exposure to biocide compounds selects for increased resistance against antibiotics, but two mechanisms are postulated, cross-resistance and coresistance. Since certain biocides and antibiotics share the same cellular targets, it is likely that some biocide resistance determinants and advantageous mutations leading to increased biocide resistance may be also responsible for the acquisition of antibiotic resistance in microbial populations. For instance, some multidrug efflux pumps, which have more than one substrate that might be chemically unrelated to each other, can confer simultaneous resistance to antibiotics and biocides when they are overexpressed [116]. This is known as cross-resistance. In addition, even for those biocides which do not share a target with antibiotics, reduced susceptibility to antibiotics can be due to the horizontal transfer of various different resistance determinants (antibiotic resistance determinants and biocide resistance determinants) associated together on common genetic elements like plasmids, phages, integrons, or transposons, which can spread to other strains, species or genera [117]. This is known as coresistance. An example of this phenomenon are class 1 integrons, which are known to contain a wide range of gene cassettes including some encoding resistance to different antibiotics and quaternary ammonium compounds. Indeed, the existence of environmental reservoirs of class 1 integrons has been known for some time and the class 1 integron-integrase gene intI1 has been recently proposed as a biomarker of selective pressures imposed by anthropogenic pollution [118,119]. Microorganisms (including nonpathogenic and unculturable) present at food and food-related environments can play an important role in the coresistance events. Indeed, they are good reservoirs of antimicrobial resistance (AMR) genes and can be facilitators for AMR gene dissemination in various environmental ecosystems, including food ecosystems [120].
What are biocide enhancers?
While biocide enhancers may be interpreted as mainly chemicals that would help the biocide not to lose its efficacy, it is possible to address other non-chemical biocide enhancers 117 such as but not limited to electric fields and ultrasound that are also used as means to remove biofilms and enhance biocides, although they are not currently being used in industries at large scales. It has been reported 118 that chemicals (Amino acids) such as d -Tyrosine, d -methionine, and d -Leucine, D-tryptophan, enhancing biocides such as THPS. In addition, biocide efficacy enhancers such as ethylenediamine disuccinate (EDDS) on nonoxidizing biocides such glutaraldehyde against SRB, 119 binary 120 and triple 121 biocide cocktails have also been reported.
What is the best biocide for a recirculatory system?
Biocides are added to cooling water to control the growth of bacteria, fungi and algae in the system. Chlorine, dosed in the form of sodium hypochlorite, is probably the best broad-spectrum biocide and, at residual levels of 0.5 mg/l, chlorine is effective against most bacteria, including Legionella. However, a recirculatory system means that bacteria are exposed continuously to the same chemical conditions, and resistant strains with a natural immunity to the biocide will eventually appear and colonize the system. To prevent this, a regular ‘shot dose’ of an alternative biocide is advisable, and most chemical suppliers have a range of biocides, both broad spectrum and specific, for this purpose.
How are biocides released?
In diffusion-controlled systems, a biocidal molecule is encapsulated in a hydrated polymeric matrix and released in solution mainly through diffusion. By contrast, in solvent-activated systems, drugs are encapsulated into dehydrated hydrophilic polymers, and the presence of aqueous solvents swells the polymeric matrix; therefore, dissolving and releasing the loaded drug deposits. Chemically controlled systems, on the other hand, utilize biodegradable or bioerodible polymers as carriers, where drug release occurs mainly by physical, chemical or biological degradation of the polymer. These systems typically contain hydrolytically or proteolytically cleavable bonds in their architectures and must produce nontoxic degradation products. Externally triggered systems make use of environmentally responsive or smart polymers as carriers, where drug release may be triggered by a variety of external stimuli, usually pH or temperature [11, 12].
What is a biocide?
Biocides are products used to control the growth of microbes and have become a necessary part of in all production Industries as the modern process and the water supply conditions in most plants greatly promote the growth of microorganisms.
What is a biocide classified on?
In some case, biocides have been classified on group basis and include a miscellaneous group that do not fit in any major class; sometimes biocides are also classified on the basis of their mode of action. This can be organized based on the target region of the microorganism affected by biocide action.
How effective are microbicides in controlling biofilm?
Certain nonoxidizing microbicides are also effective in controlling biofilm. Effective control is greatly dependent on the concentration of the product feed, frequency of addition, dosage fed, and resistance of the incumbent population to the product fed.
How do nonoxidizing biocides work?
Nonoxidizing biocides work through various processes. These biocides interfere with reproduction, stop the respiration process, or break the cell wall. They are generally shot-fed to achieve a high enough concentration for a long enough period to kill the bacteria, algae, or fungi. Kill time generally requires several hours up to a day. In some cases, nonoxidizing biocides are found to be more effective and convenient than oxidizing biocides; therefore, both biocides are used together in many conditions such as cooling water systems. Selection of a nonoxidizing biocide depends upon many factors such as water pH, retention time, efficacy against various bacteria, fungus, and algae, biodegradability, toxicity, and compatibility with the other chemistry.
What biocides are involved in rapid cell lysis?
Cationic membrane–active biocides such as chlorhexidine and quaternary ammonium compounds and alcohols such as phenoxyethanol destabilize membranes, which result in rapid cell lysis
How do biocides help plants?
Biocides are products used to control the growth of microbes and have become a necessary part of in all production Industries as the modern process and the water supply conditions in most plants greatly promote the growth of microorganisms . Biocides act either by killing the microorganisms, which ar
When should you give a non-oxidizing microbicide enough time to work?
Sufficient time should be given for the nonoxidizing microbicide to work before resuming oxidant feed unless an oxidant compatible microbicide is being used.
What is a biocide?
A biocide is defined in the European legislation as a chemical substance or microorganism intended to destroy, deter, render harmless, or exert a controlling effect on any harmful organism. The US Environmental Protection Agency (EPA) uses a slightly different definition for biocides as "a diverse group of poisonous substances including ...
Why are biocides toxic?
Due to their intrinsic properties and patterns of use, biocides, such as rodenticides or insecticides, can cause adverse effects in humans, animals and the environment and should therefore be used with the utmost care. For example, the anticoagulants used for rodent control have caused toxicity in non-target species, such as predatory birds, due to their long half-life after ingestion by target species (i.e. rats and mice) and high toxicity to non-target species. Pyrethroids used as insecticides have been shown to cause unwanted effects in the environment, due to their unspecific toxic action, also causing toxic effects in non-target aquatic organisms.
What is a biocidal product?
bacteria). Biocidal products contain one or more biocidal active substances and may contain other non-active co-formulants that ensure the effectiveness as well as the desired pH, viscosity, colour, odour, etc. of the final product. Biocidal products are available on the market for use by professional and/or non-professional consumers.
Why are biocidal products dangerous?
Hazards and environmental risks. Because biocides are intended to kill living organisms, many biocidal products pose significant risk to human health and welfare. Great care is required when handling biocides and appropriate protective clothing and equipment should be used.
How can biocides be exposed to the environment?
The environment can be exposed directly due to the outdoor use of biocides or as the result of indoor use followed by release to the sewage system after e.g. wet cleaning of a room in which a biocide is used. Upon this release a biocidal substance can pass a sewage treatment plant (STP) and, based on its physical chemical properties, partition to sewage sludge, which in turn can be used for soil amendments thereby releasing the substance into the soil compartment. Alternatively, the substance can remain in the water phase in the STP and subsequently end up in the water compartment such as surface water etc. Risk assessment for the environment focuses on protecting the environmental compartments (air, water and soil) by performing hazard assessments on key species, which represent the food chain within the specific compartment. Of special concern is a well functioning STP, which is elemental in many removal processes. The large variety in biocidal applications leads to complicated exposure scenarios that need to reflect the intended use and possible degradation pathways, in order to perform an accurate risk assessment for the environment. Further areas of concern are endocrine disruption, PBT-properties, secondary poisoning, and mixture toxicity.
What is the purpose of adding biocide to water?
Biocides can be added to other materials (typically liquids) to protect them against biological infestation and growth. For example, certain types of quaternary ammonium compounds ( quats) are added to pool water or industrial water systems to act as an algicide, protecting the water from infestation and growth of algae. It is often impractical to store and use poisonous chlorine gas for water treatment, so alternative methods of adding chlorine are used. These include hypochlorite solutions, which gradually release chlorine into the water, and compounds like sodium dichloro-s-triazinetrione (dihydrate or anhydrous), sometimes referred to as "dichlor", and trichloro-s-triazinetrione, sometimes referred to as "trichlor". These compounds are stable while solids and may be used in powdered, granular, or tablet form. When added in small amounts to pool water or industrial water systems, the chlorine atoms hydrolyze from the rest of the molecule forming hypochlorous acid (HOCl) which acts as a general biocide killing germs, micro-organisms, algae, and so on. Halogenated hydantoin compounds are also used as biocides.
How many product categories are there in the BPR?
The classification of biocides in the Biocidal Products Regulation (EU) 528/2012) (BPR) is broken down into 22 product types (i.e. application categories), with several comprising multiple subgroups:
What is non-oxidising biocide?
non-oxidising are biocides describe special chemical agents that function by mechanisms other than oxidation, including interference with cell metabolism and structure.
What is a biocide?
Biocides, as the name infers, are killers of biologicals (humans, animals, vegetables, bacteria, etc). The name represents a very large class of chemicals from “weapons of mass destruction” to weed killer to disinfectants to antibiotics and more.
What is the relationship between acids and oxidizing agents?
The experimental relationship between acids and oxidizing agents is a close one. In fact, as has been pointed out previously, the "typical" effect of an acid solution on metals is due to the oxidizing action of the solvent cation. Some early chemists attempted to explain the relationship by including oxidation as a special case of acidic behavior. Reduction was considered a special case of basic behavior. Chlorine was listed as an acid and sodium as a base. This has more experimental justification than would appear at first glance. Sodium, when reacting with water, increases the concentration of solvent anions as do bases when dissolved in many amphoteric solvents. The corresponding property of acids in amphoteric solvents, namely, the increase in solvent cation concentration, is exhibited by chlorine. On the other hand, some oxidizing and reducing agents do not have such properties of acids and bases. For example, the permanganate ion is a strong oxidizing agent, but it is not an acid. A more general classification was therefore made by dividing the reagents which take part in acid-base and oxidation-reduction reactions into two types. Electrophilic reagents are those which tend to gain electrons in the reactions considered. Electrodotic reagents are those which tend to lose electrons . (The word electrodotic is coined from the Greek word “Didomi”, meaning- “to give”) Some reagents may be electrophilic under one set of conditions while under another set of conditions the same reagents may be electrodotic. A base donates a share in an electron pair to an acid, while a reducing agent loses electrons completely to an oxidizing agent. Both are electrodotic and in many cases may act either as bases or reducing agents. It is an experimental fact that the same substance may under properly chosen conditions act as an acid, a base, an oxidizing agent, or a reducing agent. For example, water acts as an acid toward ammonia, as a base toward hydrogen chloride, as an oxidizing agent toward active metals, and as a reducing agent toward fluorine. Water is not only amphoteric but is both an oxidizing agent and a reducing agent. This is true of many other substances besides water. Most reagents cannot be arbitrarily classified as acid or base, oxidizing or reducinn - anent. Therefore, the words electrophilic and electrodotic are relative terms, depending upon conditions. They refer to the behavior of a substance as it acts in the particular reaction under consideration.
What is the difference between oxidizing and reducing?
Consider that an oxidizing agent must be reduced (gain electrons) and a reducing agent must be oxidized (lose electrons).
What is the difference between reducing and oxidizing agents?
Oxidizing and reducing agents therefore can be defined as follows. Oxidizing agents gain electrons. Reducing agents lose electrons.
Which oxidizing agent has a weak conjugate reducing agent?
Every strong reducing agent (such as Na) has a weak conjugate oxidizing agent (such as the Na+ion). Every strong oxidizing agent (such as O2) has a weak conjugate reducing agent (such as the O2-ion).
Is potassium dichromate oxidizing?
If acidified potassium dichromate is too strong an oxidizing agent then acidified potassium manganate VII (permanganate) might be a better bet. It also has a useful colour change going from purple to colourless when it has all been used up and so provides a slight pinkish colour when it is just in excess.
