NOVELTY - Producing methyl or ethyl formate from waste-water involves utilizing hydroxylated metronidazole. The hydroxylation is carried out in hydroxylation pot. The hydroxyl acid synthesis reaction is carried out in hydroxylation autoclave. The esterification reaction of liquid material is carried out by the slow addition of excess alcohol (methanol or ethanol). The amount of alcohol is calculated sum of amount of alcohol and amount of excess formic acid. The alcohol is added to the hydroxylated alcohol in the kettle and refluxed at 60 degrees C. The esterification reaction is carried out for 2 hours.    USE - Method for producing methyl or ethyl formate from waste-water (claimed).    ADVANTAGE - The method enables to produce methyl or ethyl formate from waste-water in simple, eco-friendly and cost-effective manner that has high yield and wide range of industrial applications.    DETAILED DESCRIPTION - Producing methyl or ethyl formate from waste-water involves utilizing hydroxylated metronidazole. The hydroxylation is carried out in hydroxylation pot. The hydroxyl acid synthesis reaction is carried out in hydroxylation autoclave. The esterification reaction of liquid material is carried out by the slow addition of excess alcohol (methanol or ethanol). The amount of alcohol is calculated sum of amount of alcohol and amount of excess formic acid. The alcohol is added to the hydroxylated alcohol in the kettle and refluxed at 60 degrees C. The esterification reaction is carried out for 2 hours in hydroxylation kettle. The hydroxylated material is transferred to separate reactor and esterification reaction is carried out. The material is then transferred to a distillation apparatus and subjected to atmospheric distillation to obtain methyl formate, ethyl formate and aqueous alcohol. The distilled methyl or ethyl formate, and alcohol are mixed with water. The mixture is subjected to distillation in distillation column to obtain methyl or ethyl alcohol at the top and aqueous alcohol at the bottom. The methyl or ethyl formate are transferred to ester tank. The alcohols are transferred to alcohol tank and aqueous alcohol solution is transferred to feed tank. The amount of methyl or ethyl is 97% and amount of moisture is 0.02%. The mixture is recycled for producing alcohols. The aqueous alcohols are transferred to sewage treatment station. The distillation bottom is provided with metronidazole. The precursor compound is 2-methyl-5-nitroimidazole, ethylene glycol, methyl glycol acetate, ethylene glycol monomethyl ether, dimethyl sulfate, dimethyl ether sulfate, and their derivatives. The aqueous solution of sodium sulfate and sodium formate produce metronidazole. The metronidazole is separated and purified. The solution is filtered and decolorized. The product is cooled and crystallized. The product is dried to obtain metronidazole. The 2-methyl-5-nitroimidazole is recovered. The mother liquor is concentrated by vacuum distillation and then subjected to crystallization. The product is centrifuged and separated to obtain sodium sulfate which is sold as by-product. The mother liquor is centrifuged to obtain sodium formate with very low sodium content. The solution is evaporated and then subjected to advanced electrochemical oxidation. The mother liquor is evaporated and then cooled. The product is transferred to the sewage station. The electrochemical oxidation of waste-water is carried out. The solution is subjected to oxidation-reduction, degradation and modification to achieve the requirements of biodegradation. The biological treatment is carried out according to relevant national standards for waste-water discharge. The high-boiling distillation is carried out to obtain residue at the bottom. An INDEPENDENT CLAIM is included for a device for producing methyl or ethyl formate from waste-water, which comprises esterification reactor, gas-liquid separator, distillation kettle, fine fractionator, condenser, cooler, formate esters storage tank, alcohol storage tank, aqueous solution of alcohol storage tank, distillation pot, injection pump, crystallization pot, centrifuging machine, the mother liquor storage tank and injection pump.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a methyl or ethyl formate producing device. (Drawing includes non-English language text).    Esterification reactor (4)    Gas-liquid separator (6)    Condenser (9)    Formate esters storage tank (12)    Alcohol storage tank (13)    Aqueous solution of alcohol storage tank (14)