Hydrogen sulphide help to catalyse significant processes of corrosion of steel. A product of corrosion is sulphur iron FeS. Sulphur iron does not form thick oxide film on metal and does not protect the iron from further corrosion. In addition, the presence of hydrogen sulfide in the water gives it an unpleasant odor.
Removal of hydrogen sulfide
Removal of hydrogen sulfide from water-purification process water to her deodorants and stabilizing physical (aeration), chemical (use strong oxidants) and biochemical (oxidation special bacteria) methods.
Hydrogen sulphide, depending on the pH of the water can be molecules H2s and HS in the form of ions and S2-. removed only a portion of the hydrogen sulphide H2s, which is (partly HS-). Complete removal of H2s is possible only by water acidification to pH < 5. In these circumstances, the high concentration of hydrogen ions, so the hydrogen sulphide depletion suppresses most of it will be in the molecular form that can be easily removed.
An effective method of removing hydrogen sulphide (70%)-65 is removed, no separate gearbox that is produced in various types: optimum conditions characterized by a certain ratio of air and water, excess air increases the efficiency of the release of water from hydrogen sulfide.
When the aeration of water containing hydrogen sulphide appears in contact with air, where the partial pressure of close to zero; Thanks to this, the conditions under which the solubility and concentration of H2S in the water become negligible. Aeration installations used in water purification technology of hydrogen sulfide, which use vacuum pumps, steam or water jet vacuum ejectors, calling her the water boiling temperature.
Chemical cleaning method provides the most complete decontamination. This method occur mostly oxidation of hydrogen sulfide compounds or tying them up with other molecules and move them to a less active form in water, as well as redox processes.
In domestic practice is the most common method of water purification from hydrogen sulphide with chlorine. At 1 mg hydrogen sulphide oxidized spent 2.1 mg of chlorine. It is formed by the reaction of sulfur colloid suspension in quantity, approximately equal to the quantity of hydrogen sulphide. Dose chlorine 8.4 mg 1 mg hydrogen sulphide primary products of the reaction are sulfates.
To purify water from the sulphur obtained as a result of the chemical reaction required coagulation and filtration.
To eliminate offensive odours after aeration and chlorination filtration is recommended over active carbon. In addition, for water purification from hydrogen sulphide used chlorine dioxide-in small doses in the range pH 6.8 -8.5.
The products of oxidation are mainly thiosulfate and sulfate ions, as well as sulfur and sulfite ions.
Oxidation of hydrogen sulfide air oxygen is produced only in the presence of catalysts are transition metal compounds, and its salts, organic substances.
Well-proven as the catalyst KMn04 in combination with the use of grainy weekly type MGS MGS +.
In the process of interaction between hydrogen sulfide potassium formed colloidal sulphur and manganese dioxide suspension fine, giving the water turbidity and Brown, and there is a risk of water saturation manganese and its compounds. This requires further complex water treatment.
Alternatively, apply water purification from hydrogen sulphide continuous addition of potassium permanganate in filters with processed manganese sand (MGS MGS +), which is used for removing soluble iron, manganese and hydrogen sulfide, while the sand is recovered using potassium permanganate.
Processed manganese sand receive sequential washing his solutions of salt of manganese and potassium permanganate. This sand is a black granular mineral that serves as contact oxidation filter material and environment.
Fairly widespread method to remove hydrogen sulfide from water, namely continuous filing 1-4% solution of potassium permanganate in surface upstream of the filter processed manganese sand, covered with filter material from anthracite (us silica-alumina Sorben type materials are recommended as several inches thick.
Forming insoluble products delayed filter. If the dose of potassium permanganate is insufficient, then processed manganese sand can remove non oxidized hydrogen compounds, and if set too high, then sand uses excess potassium permanganate for its regeneration.
During the reaction of potassium permanganate is restored to insoluble manganese hydroxide, which acts as both a coagulant, and as adsorbent.
The technology of removing hydrogen sulfide from water using hydrogen dioxide. As a result of processing of water it produces sulfur, with further filtering the water through activated charcoal odor and color fade, increases the amount of dissolved oxygen, which facilitates further water purification from hydrogen sulfide.
Water purification from last apply iron hydroxide. When added to water slurry hydroxide of iron sulfide hydrosulfide ion binding occurs with formation of iron sulfide. It is separated from the water sedimentation sludge, after which it can be regenerated by blowing air. One and the same iron hydroxide suspension can be reused with some addition of iron salts. When applying this method is achieved almost complete water purification from hydrogen sulfide.
Effective and strong oxidant for sulphurous compounds in water is ozone. Ozone water treatment simultaneously achieved its discoloration, deodorizing and disinfecting.
Sulfur compounds are oxidized to elemental environment, and at the expense of 1.87 mg ozone on 1 mg hydrogen sulphide hydrogen sulphide oxidation process ends with the formation of sulfuric acid.
One of the options for water purification from hydrogen sulphide-sorption. As adsorbents in most cases use wood active carbons. Together with active coals can use different oxidizers, reducing overall consumption and volume of sorbents and reagents. The adsorption process is severely affected by the structure of coal (mainly the volume of micropores) hydrogen sulphide concentration in source water, as well as the structure oxides formed on the surface of coal during the process of adsorption of hydrogen sulfide. These methods implement the coal open or pressure filters with prior entering an oxidizer in treated water.
In the purification and organic dirty water finds a place of biological treatment technology of hydrogen sulfide. When the biochemical purification from hydrogen sulphide oxidation it happens in a result of active silt, frequently encountered in sulphur, soil and biofilms.
For mass development of these organisms to the presence in water of hydrogen sulfide and oxygen and nutrients, phosphorus, and potassium. In some cases, microorganisms develop bad if there are missing elements: iron, magnesium, zinc, copper, molybdenum, boron, manganese, cobalt.
Biochemical method of implement, using two-tier scheme-, precipitation-mixer-secondary clarifier, biochemical reactor oxidation) and quick filter. To avoid anaerobic conditions in the lower layers of the load the filter and to prevent the recovery of sulphur to hydrogen sulphide it is recommended the introduction of chlorine in a water pillow filter or periodic purge download compressed air from the bottom up.