CS269546B1 - Method of waste waters treatment - Google Patents

Abstract

They manage the methods of waste treatment water from 1,5-methane-3,7- dinitroso-1,3,5,7-tetraazocyklooktánu pressure or atmospheric decomposition mineral acid and photochemical decomposition of organic substances with timely economic appreciation pollutants.

Description

CS 269 546 B1 1

BACKGROUND OF THE INVENTION The present invention relates to a process for treating wastewater from the manufacture of 1,5-methano-3,7-dinltrozo-1,3,5,7-tetrasocyclooctane comprising nitrates and nitrites of alkali metals or alkaline metal metals, condensation products of formaldehyde and ammonia. and a small amount of other organic matter, by atmospheric or pressurized solution with a mineral acid. 1,2,5-Metano-3,7-dinitrozo-1,3,5,7-tetraazocyclooctane (code-named DNPT) is produced by nitrosolysis of hexamethylenetetraamine. Waste water from its production I get! about 16% alkali metal or alkaline earth nitrate, 1.8% alkali metal or alkaline earth nitrite, 2.4% formaldehyde, varying amounts of N-nitrosamines, mainly 1,3,5-trinitrozo-1,3, 5-triazocyclohexane and N-nitrosodimethylamine and a small amount of Saline organic compounds. 1.3.5-trinitrozo-1,3,5-triazocyclohexane is produced by ONPT as a by-product, N-nitrosodimethylamine is mainly formed when it is used on nitrosolysis! fine solutions from the production of crystalline hexamethylenetetraamine containing dimethylamine, but its increased content was also observed by thermal stressing of a solution containing 1,3,5-trinitroso-1,3,5-triazocyclohexane. There is a known method of removing formaldehyde and nitrites from such effluents according to the Czechoslovak AO No. 234 447. The disadvantage of this method in terms of environmental protection is that the N-nitroso compounds are not removed. Another disadvantage of said AO No. 234,447 is that the inorganic salt obtained (e.g., sodium nitrate) has a limited use in terms of the water-insoluble residue, resulting in the subsequent loss of urea-formaldehyde condensate from the solution.

This problem is more aptly solved by the Czechoslovak AO No. 185 888, which deals with the treatment of mother liquors from the production of ONPT for the preparation of pure salt. However, the present invention does not solve the problem of the removal or degradation of dangerous N-nitroso compounds as mentioned by the 1,3,5-trinitrozole. 1,3,5-triazocyclohexane and N-nitrosodimethylamine, nor does it indicate the possibility of degrading volatile N-nitrosoamines in volatile organic fractions after separation by distillation of the effluent with mineral acid.

A process for treating wastewater from the production of 1,5-metano-3,7-dinitrozo-1,3,5,7-tetraazocyclooctane containing alkali metal nitrites and nitrates of alkali metal or alkaline earth metal, condensation products of formaldehyde and ammonia and small amounts of other organic compounds by atmospheric or pressure the mineral acid decomposition of the present invention consists in disposing the mineral acid to waste streams in a ratio of 0.3 to 0.8 moles of acid, preferably nitric acid, per mol of the formaldehyde content of the wastewater, and in the treatment of wastewater ultraviolet light, preferably ultraviolet light having a wave length of 300 to 350 mm, irradiating the waste water after separation from the inorganic salt solution, most often from an alkali metal nitrate or an alkaline earth metal, to which distillation is utilized and the distilled formaldehyde-containing distillate is worked up in a known manner reaction with urea.

The formaldehyde is left in the distillation residue, i.e. in the nitrate solution to be crystallized, in an amount of from 1 to 1000 mg per kg of resulting nitrate, ensuring that the nitrate produced is resistant to caking. An advantage of the treatment according to the invention is that the produced effluent waste products, namely alkali metal nitrate or alkaline earth metal nitrate and urea phosphorous aldehyde condensate, are free of the unwanted organic compounds, in particular the N-nitroso compounds.

In addition, the resulting nitrate produced is non-fermented. Example 1

53.3 kg of 52% nitric acid at a temperature of 1 kg of wastewater with a total content of 24 kg of formaldehyde, 143 kg of sodium nitrate, 14 kg of sodium nitrite dissolved and suspended by N-nitroacetates in a total amount of 0.6 kg 100 ° C and overpressure 0.075 MPapo time 20 min. After decomposition, the sodium bicarbonate solution was concentrated in an evaporator. The distillate from the thickening was worked up as described in Example 2.

The sodium nitrate solution as the distillation residue was neutralized with sodium hydroxide to a pH of 7 and after evaporation it contained 0.2 g of formaldehyde per liter of dissolved sodium nitrate. Sodium nitrate so produced was not caking and N-nitrosodimethylamine was not found in it.

The crystallized and dried sodium nitrate was 99.60% and still contained 0.004% water insoluble and 0.055% sodium chloride. Example 2

The distillate obtained by evaporating the decomposed waste water from Example 1 contained formaldehyde at a concentration of 28 g / l and N-nitrosodimethylamine at a concentration of 58.9 mg / l was subjected to UV light irradiation from a source of Hg-prikonom500 W / manufacturer Chirana CSSR / v a dish with a diameter of 1 cm, a thickness of irradiated layer of 9 mm from a distance of 10 cm. N-nitrosodimethylamine content was determined by gas chromatography with NP detector for 15 min. to 6.7 mg / l, after 20 and 30 min, no N-nitrosodimethylamine was found. The formaldehyde solution was treated with a known urea treatment method. By irradiating the same solution at low conditions with a source of 60 W and producing light with a wavelength close to 300 to 350 nm, the effect on the concentration of N-nitrosodimethylammonium is. Example 3

Wastewater as in Example 1, containing 39.2 mg / l of N-nitrosodimethylaminone irradiated with UV light from the source as in Example 2. N-nitrosodimethylamine content found after 15 min. was 9.14 mg / L, after 30 min. was 6.29 mg / L, after 60 min. 2.6 mg / l.

Claims (2)

Example 269 Wastewater of composition as in Example 1 containing 0.5 kg of 1,3,5-trinotrozo-1,3,5-triazocyclohexane was subjected to UV light irradiation as described in 2, 1,3,5-trinitrozo-1,3,5-triazocyclhexane was monitored by UVspectra (Specord 40 M, NOR). The content of this substance was found to decrease after 15 min. to 57.8%, after 30 min, to 19.6%, after 45 min. to 11.1%, after 60 min, to 4.9% of the flood concentration. The flooded rye colored water from the pooled compound was discolored. SUBSTITUTE Waste water treatment plant for the production of 1,5-metano-3,7-dinitrozo-1,3,5,7-tetraazocyclooctane, containing nitrites and nitrates of alkali metal or alkaline earth metals, condensation products of formaldehyde and ammonia and small amounts of Salsh organic compounds by atmospheric or pressurized mineral acid, characterized in that the waste water is treated with a mineral acid in a ratio of 0.3 to 0.8 moles of mineral acid, preferably nitric acid, per mole of total content The effluent is subjected to ultraviolet light, preferably ultraviolet light, with a wavelength of 300 to 350 nm, irradiating the wastewater after separation from the inorganic salt solution, most often alkali metal nitrate, to separate the distillation is used and the distillate is treated with a known urea treatment method.