Ozone in Drinking Water
Why Ozone application is widely recommended for drinking water?
It is essential to use ozone application throughout drinking water treatment process during pre-oxidation and in-between oxidation. During pre-oxidation, an active carbon filter (GAC) purify the water that remove rest of the remaining organic matter. The other key highlights of the oxidation process involve.
– Removal of organic and inorganic matter.
– Removal of micro-pollutants pesticides
-Enhanced disinfection and reduction of disinfection by-products.
-Odor and taste removal during pre-oxidation.
Removal of organic matter and inorganic matter
Water resource control natural organic matter (NOM). It is only when the NOM is detached, we get crystal clear transparency. Concentrations (usually measured as dissolved organic carbon, DOC) differs from 0.2 to more than 10 mg. NOM contributes to bad odor, unlike taste in water and generate indirect problems such as, bacterial in the distribution system.
Ozone rarely performs a whole mineralization of NOM. Organic issue is partly oxidized and biodegradable. This results in a higher amount of BDOC (Biodegradable DOC). As a result, ozone improves the removal process of NOM by a subsequent filter, when it is used as a pre-oxidant. The removal is exceptional when ozone is blended with a coagulant and can enhance the coagulation development. The combination coagulation–ozone–bio filtration results in a DOC decrease of 64%.
When only bio-filtration is applied, the reduction rate is only 13%. The optimal concentration to eradicate organic matter by ozone was at an ozone dose O3/DOC = 1 mg/mg. Most inorganic matter can be eliminated by ozone quickly [15,39]. After ozonation, bio-filtration is essential for inorganic substance. Oxidization shape insoluble compounds which would be removed during the next water purification level.
Pesticides primarily occur in surface water but micro pollutants exceptionally affect drinking water values. Ozone is a really powerful disinfectant and oxidizer. Disinfection byproducts (DBP) are usually formed during the reaction between an organic material and a decontamination. To exemplify, the reaction of chlorine with organic matter can lead to the formation of chlorinated organic such as trigonometrical (THM). Compare to Chlorine, the most ordinary water disinfection substance, Ozone is twice as powerful has an oxidizer and perform over 3,000 times quicker. Equally Chlorine and Fluorine are highly toxic chemicals. Drinking-water standards for pesticides in the European Union are strict: 0, 1 μg l-1 for each complex and is productive as an oxidation of several pesticides.
Ozone is a extra effective disinfectant than Chlorine, Chloramines, and even Chlorine dioxide. An Ozone dose of 0,4 mg L-1 for 4 minutes is usually effective for pre-treated water (low NOM concentration). Several studies have shown that ozone, unlike Chlorine products, can disable resistant micro-organisms. Also, Ozone speedily decomposes in water, its duration in aqueous clarification is within a span of time (less than one hour). Therefore Ozone is less suitable for residual disinfection and can be used only in particular cases (mainly in short distribution systems). Chlorine and Chlorine dioxide often replace Ozone as a final disinfectant. For most important disinfection (prior to bio-filtration), Ozone is very useful. This will lead to a complete disinfection and a lower disinfectant concentration.
Odor and taste elimination
Odor and taste production in drinking water can have several causes. Odor and taste forming compounds can be present in raw water, but they can also be formed during water treatment. These compounds may derive from the decomposition of plant matter, but normally they are a result of the activity of living organisms present in the water . Inorganic compounds such as iron, copper and zinc can also generate some taste. Another possibility is that the chemical oxidation (chlorine treatment) leads to an unpleasant tastes and odors.
Odor and taste forming compounds are often very resistant. This causes elimination to be a very intensive process. For the elimination of taste and odor, several processes can be appropriate, such as oxidation, aeration, granular active carbon (GAC) filtration or sand filtration. Usually, a combination of these techniques is applied.
Ozone can oxidize compounds in a range of 20–90% (dependent on the type of compound). Ozone is more effective for the oxidation of unsaturated compounds. As was the case for the oxidation of pesticides, ozone combined with hydrogen peroxide (AOP process) is more effective than ozone alone. Geosmin and 2-methylisoborneol (MIB) are examples of resistant odorous compounds, which are often present in the water. These are produced by algae and have a low odor and taste threshold. Nevertheless, ozone is still very affectively removes these compounds, see