Use of biocides

Offshore oil production is one area in which environmental pollution has been highlighted as an issue, particularly in the use of biocides in production waters. Tetrakis-hydroxymethyl phosphonium salts exhibit acceptable environmental profiles [1120], and they are regarded as the preferred products for bacterial control within the oil production industry. 

Good plant hygiene procedures are critical to maintaining an effective production, however due to the nature of the process, this will not be wholly effective and the use of biocides is critical to maintain a low microbiological population to prevent paper failure. The table below (Table 4) illustrates the types of biocides that are commonly encountered within the paper processing. 

Although there are many biocide alternatives available on the market, for example enzyme technology or bio-dispersants, there appears to be a continued requirement for the use of biocides in order to reduce the levels of microbiological contamination entering the paper making process. The increased awareness of environmental and safety aspects will continue to play an important role on the selection of biocides for paper making processes. The use of legislation to select biocides must be done in parallel with each plants internal risk assessment. No one biocide active will meet all the criteria set out by different European countries and hence the use of these actives must be carefully assessed on a plant by plant basis. 

Biocides are by their nature intrinsically toxic, in this respect any adventitious release to the environment requires an assessment of the relative risk posed. The 5th Environmental Action Plan of the EU is committed to a substantial reduction in the use of biocides. In particular, the Biocidal Products Directive (98/08/EC) is concerned with controlling biocidal products in the market place. Compliance with this directive is required from all member states by 14th May 2000. In this context, a strategy to control the release of biocides is timely, if continued protection is to be afforded to industry and consumer alike. One approach to controlling the release of biocide is to encapsulate in an inert inorganic framework, prior to incorporation in the coating.1... 

Numerous applications for biocides have been found in fields as diverse as ethical pharmaceuticals and cat litter products. The aim of this Cl book is two-fold to provide a comprehensive guide to the use of biocides across a range of applications and to aid in the selection of a biocide that is "fit for purpose". It covers a Cl cross-section of traditional measures, novel ideas and innovative developments, as well as addressing the biocides market, the political outlook and future trends of biocide use. 

The use of biocides is in Europe controlled and regulated by the EU Biocidal Products Directive [15]. Registration of a biocide is expensive and only a few active biocide substances will in the future be available for the leather industry in the EU. The directive will include a list of active substances that are permitted to use by the leather industry (a so-called positive list). Many eco-labels and RSL does already today include restrictions of the use of some biocides. 

Biocides are naturally toxic to lower organisms and therefore must be handled with care. Strict government rules control the sale and use of biocides, especially those used in food contact applications. They are added at the fabrication stage. The morphology of the polymer article is important, e.g., high surface area articles, such as foams, biodegrade more rapidly. 

The use of biocides is spread across the whole polymer range, e.g., paints, ropes, textiles, fibres, etc. Many are copper, silver or arsenic compounds and also various heterocyclic compounds, e.g., isothiazolines (which have some structural resemblance to penicillin). 

Conservation Avoid use of biocides that disrupt natural enemies and competitors Common Occasional... 

The term biocide will be used in the discussion, although in many cases organisms may only be inhibited rather than destroyed (B-76MI11500). One important consideration in the use of biocides is that they are toxic materials, exhibiting varying degrees of hazard to both man and the environment. In most countries, therefore, these materials are subject to controls. 

Health, Safety, Responsible Care, and Environmental Legal Problems Related to the Use of Biocides... 

In the United States, the European Union, and many other countries, as has been mentioned earlier, there are regulations that control the use of biocides and other types of chemicals in industrial situations. Successful efforts to clean up rivers, improve working environments, and remove pollutants from being discharged cannot just be ignored or overridden. The cooling system operator often has a duty to review all water treatment chemicals, including biocides, prior to their potential use on-site. The owner may have rules in place over what biocides are or are not acceptable in the workplace. 

The various issues concerning the possible use of biocides often form part of a company s chemicals risk assessment program, and thus may involve the following considerations ... 

Chlorinated aromatic compounds are hazardous compounds that result from various industrial and agricultural activities. Water disinfection, waste incineration, and uncontrolled use of biocides are the major sources of chlorinated aromatics in the environment. Chlorinated compounds are also formed as subproducts of the biochemical reactions of herbicides containing chlorophe-noxy compounds. Treatment of chlorinated compounds has been studied using biological treatment, adsorption, air stripping, and incineration. Biodegradation of chlorinated compounds is a slow process that is ineffective for extremely low concentrations. Air stripping and adsorption simply trans-... 

Production equipment that cannot be sterilized must be sanitized and disinfected by an appropriate method. This can be done by use of biocides like alcohols (70%), hydrogen peroxide, or formaldehyde-based chemicals or a combination of these. These can either be used for surface disinfections by wiping or spraying or even better by use of gas or dry fog systems for application of the disinfectants. The effect of cleaning and sanitation should be monitored. Microbiological media contact plates can be used to test critical surfaces, as inside the hot cells or glove boxes. The test samples must then be handled and monitored as radioactive contaminated units. 

Arsenic pollution can be originated in anthropic activities (mining, use of biocides, wood preservers). However, most pollution is natural, coming from mineral dissolution in surface or groundwaters (Bundschuh et al., 2000, 2004 Litter, 2002). Predominant As forms in natural ground and surfacewaters (neutral pH) are arsenate (As(V), as H2AsO and HAsO ) and arsenite (As(III), as neutral H3ASO3). The mobility of arsenical forms in waters is very dependent on pH, Eh conditions, and presence of different chemical species (Smedley et al., 2002). Consequently, removal methods... 

Cause infectious and other diseases Immunology and infectious diseases Characteristics, selection and use of vaccines and antibiotics Use of biocides in infection and contamination control Control of antibiotic resistance... 

The problem of bioactivity can be reduced or eliminated by the use of biocides. There are different types of biocides and one must be aware of the toxicity level of these to decide the most suitable biocide for that application. Already affected systems can be treated with biocides but it is very difficult to release the biofilm once it is formed. In that case a biocide treatment... 

The use of biocides in plastics is commonplace. They are added to protect the plastic itself from degradation by microbes or alternatively to provide an external antimicrobial hygienic surface. The choice of suitable test method and the appropriate biocide can be difficult, as the different ways in which biocides work will affect how they perform under certain test protocols. 

Indeed, it can be assumed that use of biocides in this application field would only be of benefit but this may not be the case in some instances. 

Legislation on the use of biocides in plastics varies by eountry and application. 

Under this directive, the use of biocides in plasties and rubber application falls under one of several seetions. Each product type will be examined over the next few years until all application areas are covered. These areas include ... 

The use of biocides in coatings is discussed with reference to reasons for using combinations of biocides, effects of global regulations, biocide selection, and advances in combination technology (combination biocides for in-can preservation and for diy-film protection). 

ENVIRONMENTALLY ACCEPTABLE PAINT PRODUCTION. A CHALLENGE ALSO FOR OPTIMISING THE USE OF BIOCIDES... 

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