Electroplating waste water treatment method

Patent metadata

Field	Value
Publication number	US-9708202-B2
Application number	US-201314412218-A
Country	US
Kind code	B2
Filing date	Mar 27, 2013
Priority date	Apr 28, 2012
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

An efficient combined advanced treatment method of electroplating wastewater is disclosed, which belongs to the technical field of electroplating wastewater treatment. The method includes: after pretreatments including cyanide breaking, dechromization and coagulating sedimentation, introducing the electroplating wastewater to a contact oxidation tank for biochemical treatment, and settling the effluent from the contact oxidation tank down in an inclined pipe of a secondary sedimentation tank to realize the separation of the sludge from water; charging the effluent to a coagulating sedimentation tank, and undergoing coagulating sedimentation with the aid of a flocculant and a coagulant aid added; feeding the effluent, as an influent, to a resin adsorption tank for adsorption with a magnetic resin; and after passing through a filter, flowing the effluent after adsorption to a fixed bed resin adsorption unit, so as to realize the discharge up to standard and recycle of the effluent.

First claim

The invention claimed is:

1. An efficient combined advanced treatment method of electroplating wastewater, comprising:
(1) subjecting the electroplating wastewater to pretreatments including cyanide breaking, dechromisation and coagulating sedimentation;
introducing the pretreated electroplating wastewater to a contact oxidation tank for biochemical treatment;
settling an effluent from the contact oxidation tank in a secondary sedimentation tank to form a sludge and a first liquid,
wherein, in the pretreated electroplating wastewater, concentrations of Cu 2+ and Ni 2+ are below 2.0 mg/L, a concentration of cyanide is below 2.0 mg/L, and COD is 80 to 200 mg/L;
(2) feeding the first liquid from the step (1) to a coagulating sedimentation tank, and adding a flocculant and a coagulant aid into the first liquid to remove suspended solids, Cu 2+ and Ni 2+ in the first liquid by settlement and to obtain a second liquid;
(3) mixing the second liquid from the step (2) with a magnetic resin to form a mixture; separating the magnetic resin from the mixture to obtain a third liquid; and
(4) filtering the third liquid from the step (3) using a filter and feeding the filtered third liquid to a fixed bed resin adsorption unit, wherein an effluent from the fixed bed resin adsorption unit is discharged or subject to further treatments.

2. The efficient combined advanced treatment method of electroplating wastewater according to claim 1 , characterized in that in the step (1), the pretreated electroplating wastewater in the contact oxidation tank is at a pH of 6.5 to 8 and at a temperature of 15 to 30° C., biodegradable nutrients are manually added into the pretreated electroplating wastewater to adjust the BOD/COD to 0.3 or above, and the dissolved oxygen (DO) content is controlled at 2 to 5 mg/L by means of intermittent aeration, and wherein the sludge generated in the contact oxidation tank is filter-pressed by a plate and frame filter press, and then the dry sludge is transported for treatment.

3. The efficient combined advanced treatment method of electroplating wastewater according to claim 2 , characterized in that, in the step (2), the flocculant is selected from a group consisting a polyferric flocculant, a polyaluminum flocculant, a polyaluminum-ferric flocculant, and mixtures thereof, and the coagulant aid is polyacrylamide, wherein the flocculant is in an amount of 1 to 5‰ by volume of the first liquid, and the coagulant aid is in an amount of 0.1‰ by volume of the first liquid.

4. The efficient combined advanced treatment method of electroplating wastewater according to claim 3 , characterized in that, in the step (3), the magnetic resin is in amount of 1 to 20‰ by volume of the third liquid, and the magnetic resin is separated from the mixture by gravity settling with mechanical stirring.

5. The efficient combined advanced treatment method of electroplating wastewater according to claim 4 , characterized in that, the filter in the step (4) is a sand filter, activated carbon or a fiber ball filter device; and in the fixed bed resin adsorption, the resin is selected from a group consisting of a cation exchange resin, an anion exchange resin, a chelating resin, an ultra-high cross-linked resin, and mixtures thereof.

Assignees

• Nanjing University Of Technology
• Nanjing Univ Yancheng Env Prot Tech And Eng Res Inst

Inventors

• Li Aimin
• Fu Lichun
• Liu Fuqiang
• Zhou Qing
• Dai Jianjun
• Lu Zhaoyang
• Li Yan
• Shuang Chendong
• Wang Jinnan
• Zhao Weiwei

Classifications

• C02F1/5245

  using basic salts, e.g. of aluminium and iron · CPC title

• C02F9/00 Primary

  Multistage treatment of water, waste water or sewage · CPC title

• C02F2201/46105

  Details relating to the electrolytic devices · CPC title

• C02F1/42

  by ion-exchange (ion-exchange in general B01J) · CPC title

• C02F2101/20

  Heavy metals or heavy metal compounds · CPC title