CS276293B6 - A method of treating wastewater from the production of a conductive fiber - Google Patents

Abstract

The wastewater is mixed with 10 to 100 mg.l 1 · ferrous or ferric ions, the pH of the wastewater is adjusted to 6. to 9 and 1.5 to 2 mg.l-1 of a polymeric flocculant based on polyacrylamide with an anionic charge and a relative weight of 5.10® to 10.10® is dosed. In case of insufficient precipitation of manganese sulfide, 50 to 100 mg. •I-1 of bentonite can be added with subsequent addition of a polymeric flocculant in a maximum amount of 2 mg.l based on polyacrylamide with an anionic charge and a relative weight of 5.10® to 10.10®.

Description

The invention relates to a process for the treatment of waste water from the production of fibers with electrically conductive properties.

Wastewater is generated during the application and fixation of copper sulfide to the fiber and during its washing. These operations produce about 40 m ^{3 of} acidic wastewater per day, containing 40 to 60 mg.l ^{1 of} copper. Copper is in the wastewater in the form of colloidal copper sulfide, which cannot be separated by sedimentation or filtration. It enters the sewer, which contradicts water management regulations. The conventional coagulation process, which consists in neutralization with lime and subsequent addition of aluminum sulphate, does not achieve satisfactory results, both in terms of operational efficiency and in terms of increased production of waste coagulation sludge, with reagent doses ranging from 100 mg to grams depending on on the content of undissolved substances and the type of reagent. Sludge production is more than 50% of the volume of wastewater, sludge is difficult to separate with unfavorable thickening and dewatering properties.

These disadvantages are substantially reduced by the method of treating wastewater from the production of an electrically conductive fiber, according to the invention. Its essence lies in the fact that the waste water is mixed with 10 to 100 mg.l of ferrous or ferric ions, while the pH of the wastewater is adjusted to 6 to 9 with, for example, sodium hydroxide solution and 2 mg.l ^{1 of} polymeric flocculant based on polyacrylamide with anionic charge and relative weight 5.10® to 10.10®. In case of insufficient precipitation of copper sulphide, 50 to 100 mg.l ^{1 of} bentonite can be added followed by addition of polymeric flocculant in a maximum amount of 2 mg.l ¹ based on polyacrylamide with anionic charge and relative weight 5.10® to 10.10®.

The main advantage of the wastewater treatment method according to the invention lies in the higher coagulation efficiency at lower doses of coagulating agents, including the organic flocculant. The resulting sludges have favorable filtration properties and their production does not exceed 1.0% of the original volume of wastewater. The concentration of undissolved substances with the wastewater treatment method according to the invention is reduced below 30 mg.l ¹ and the residual copper concentration is around 1 mg.l

The method of wastewater treatment is further illustrated by the following examples:

Example 1

To 4 l of a sample of wastewater with a dry matter of 1,900 mg.l ^- · ¹ · and a concentration of undissolved substances of 68 mg.l ¹ consisting of 50 mg of Cu ₉ S and 18 mg of synthetic textile fiber based on ^Z -1 lyacrylonitrile was added 25 mg FeSO 4 and the pH were adjusted to 9 with sodium hydroxide solution. After the addition of 2 mg / ^{l of a} polymeric flocculant based on polyacrylamide with a relative weight of 5.10%, coagulation took place. After 30 minutes of sedimentation, a water sample was taken for analysis. The copper concentration was 1.1 mg / ^L and the insolubles were 26 mg / L. ^-1 .

Example 2

To 10 l of a sample of waste water with a dry matter of 2,100 mg.l ^- · ¹ and a concentration of undissolved substances of 172 mg.l consisting of 70 mg of Cu ₉ S and 102 mg of synthetic textile fiber based on po. 25 mg / l of FeSO 4 was added to the lyacrylonitrile and the pH was adjusted to 6.2 with sodium hydroxide solution. After stirring for 10 minutes, an organic flocculant with a relative weight of 9.10® was added at a concentration of 2 mg.l, followed by the addition of bentonite at a dose of 100 mg.l · ¹ · and again a polymeric flocculant at a dose of 2 mg.l ¹ . After stirring for 15 minutes and sedimentation for 30 minutes, a sample was taken for analysis. The concentration of copper in the treated water was 1.1 mg.l ¹ and the concentration of insoluble matter was 21 mg.l.

Example 3

To a 9 L sample of the wastewater from Example 2 was added 60 mg / L of FeCl 2, and the pH was adjusted

-1 ^J sodium hydroxide to 8.5. After the addition of 2 mg / l of the organic flocculant from Example 2, coagulation took place. After half an hour of sedimentation, a sample was taken for analysis. Concentration

Cu was 0.46 mg.l and the concentration of insoluble matter was 18 mg.l. The volume of the sludge was 80 ml, i.e. 0.9% of the original sample volume. .

Claims (1)

PATENT CLAIMS A process for the treatment of waste water from the production of an electrically conductive fiber, characterized in that the waste water is mixed with 10 to 100 mg / l of ferrous or ferric ions, the pH of the waste water being adjusted to 6. for example up to 9 with sodium hydroxide solution is metered from 1.5 to 2 mg.l "polymeric flocculant, based on polyacrylamide and anionic charge, and the relative weight of up to $ 5.10 10.10® with the possible addition of bentonite in an amount of from 50 to 100 mg.l ^- '''s by the subsequent addition of a polymeric flocculant in an amount of max. 2 mg.l ”based on polyacrylamide with an anionic charge and a relative weight of 5.10® to 10.10®.