Water surface decontamination

DAF is used to remove suspended solids by decreasing their apparent density they then rise and float on the water surface. DAF is also used to remove soluble iron, VOCs, oils, and surface active agents by oxidation, air stripping, and surface adsorption. The flotation technology is becoming one of the most important technologies for groundwater decontamination, industrial effluent treatment, and water purification.58-6170... 

Atmospheric conditions and particle size determine the persistence of aerosolized toxin in the environment. Temperature and humidity extremes facilitate toxin degradation, and smaller particles dissipate more quickly into the atmosphere. Studies estimate that aerosolized toxin would decay between less than 1 and 4% per minute. At a 1% decay rate, insubstantial amounts of toxin would remain after 2 days (36). Although botulinum toxin can penetrate mucosal surfaces, it cannot penetrate intact skin. If a release were recognized or announced, and authorities anticipated potential airborne exposure, people could protect themselves by covering their mouths and noses with clothing, such as underwear, shirts, scarfs, or handkerchiefs. In addition, after exposure, washing with soap and water would decontaminate clothing, and a 0.1% hypochlorite bleach solution would be effective on contaminated objects and surfaces (36). 

A. Operational rations are safe when surface decontamination is performed before breaking the package. The package should be thoroughly washed with water to remove the contamination. 

Contamination of the inner surface of the secondary circuit gives rise to danger in case of equipment repair, since the alloy kept in the secondary circuit is a permanent source of water contamination. Water replacement and SG inner surface decontamination without any alloy removal would not give the desired result. The secondary circuit decontamination turns out to be possible only after complete removal of the alloy from the secondary circuit. Obviously, this cannot be assured. 

Work clothes will prohibit, at first, the direct contact of the chemical with the skin. This is the screen effect. But beware that once the contamination is confirmed, it will be highly recommended to quickly remove contaminated clothing as otherwise soaked product could act as a reservoir extending the dnration of contact. We must learn, after contact with a chemical, immediately to undress while implementing an effective surface decontamination with water or with more specific solntions (see Sect. 4.6). 

Other physical properties are also important. Surface tension determines the extent of spreading [e.g. oil versus water). Most liquid CW agents resemble organic liquids or oils, and have a significantly lower surface tension than water. They tend to spread on surfaces, getting into parts that are difficult to decontaminate with water-based decontaminants. Viscosity determines thickness, how readily an agent sticks to surfaces, and drop size on dissemination. 

If required, immediate casualty decontamination for biological agents can be carried out effectively with detergent and water. Surfaces and equipment should be carefully disinfected with an appropriate detergent or bleach solution. Medical utensils will ideally be of the single-use, disposable t)q>e. Multi-use items will need cleaning and disinfection as appropriate, such as steam heating in autoclaves. 

Sulfur mustard reacts rapidly with chlorine or with bleach, and this reaction is a suitable means of decontamination. Nitrogen mustards, however, chlorinate extremely slowly thus chlorination is not suitable for their decontamination. The formation of water-soluble salts, such as by neutralization with sodium bisulfate, is the usual method for nitrogen mustard removal from contaminated surfaces. The mustard salts are much less vesicant than the corresponding free bases. 

One such decontaminant is supertropical bleach (STB). STB is a mixture of chlorinated lime and calcium oxide containing about 30% available chlorine. It can be used either as a dry mix or as a slurry to decontaminate some equipment surfaces and terrain. The dry mix is prepared with two parts bleach to three parts earth by volume. A slurry typically consists of 40 parts STB to 60 parts by weight of water. This material is then sprayed or swabbed on the contaminated surface (see Bleaching agents). STB is an effective decontaminant for mustard, lewisite, and VX. It is less effective against nerve agents other than VX. 

The etched printed circuit boards are washed out with water to dilute the concentration of the contaminants on the board surface to an acceptable level. The extraction of copper from the effluent rinse water is essential for both environmental and economic reasons since decontaminated water is returned to the rinse vessel. 

The whole system should be designed for ease of decontamination. The cupboard will incorporate a wash-down system. Adequate drainage in the cupboard and ductwork is required. Water drained from the system, including that from the fan casing, should be collected and properly disposed of. It should not be possible for water to get onto the work surface. 

The attraction between the air bubble and contaminants is believed to be primarily a result of particle surface charges and bubble size distribution. The more uniform the distribution of water and microbubbles, the shallower the flotation chamber can be. Generally, the depth of effective flotation chambers is between 0.9 and 2.7 m (3 and 9 ft). Flotation units can be round, square, or rectangular. Gases other than air can be used. The petroleum industry has used nitrogen, with closed vessels, to reduce the possibilities of fire. Ozone can be fed through with air for more efficient reduction of soluble iron, VOCs, and so on.57 Ozone-UV flotation is another alternative for groundwater decontamination. 

Small areas Ventilate to remove the vapors. If condensation is present, decontaminate with copious amounts of a decontamination solution as described in Section 1.6.1. Collect and place into containers lined with high-density polyethylene. Wash the area with copious amounts of soap and water. Collect and containerize the rinseate. Removal of porous material, including painted surfaces, maybe required because the nerve agent that has been absorbed into these materials can migrate back to the surface posing both a contact and vapor hazard. 

Use a sponge or cloth with liquid soap and copious amounts of water to wash the skin surface and hair at least three times. Do not delay decontamination to find warm or hot water if it is not readily available. Avoid rough scrubbing as this could abrade the skin and increase percutaneous absorption of residual agent. Rinse with copious amounts of water. If there is a potential that the eyes have been exposed to nerve agents, irrigate with water or 0.9% saline solution for a minimum of 15 minutes. 

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