CN103086536A - Method for processing chromate waste water - Google Patents

Abstract

The invention discloses a method for processing chromate waste water. The method comprises the steps of adjusting pH of waste water to 1-3 by a modifier, wherein the modifier is concentrated sulfuric acid; adding a reducing agent, wherein the reducing agent is sulfur dioxide, sodium sulfite and metabisulphite; adding NaOH to neutralize, adjusting pH to 8.5-8.8; controlling the neutralization time at 10-12 minutes; and then adding a flocculating agent PEO (poly ethylene oxide), wherein the stirring speed is 60-80r/min; the settling time is 40-60 minutes; the settled clear liquid can be discharged, and the settled solid matter can be recycled after being dried. The method disclosed by the invention is good in treatment effect, simple in equipment, easy to operate and low in expenses.

Description

A kind of method of processing waste water containing chrome

Technical field

The present invention relates to wastewater treatment, specifically a kind of method of processing waste water containing chrome.

Background technology

Present widely used chromium containing waste water treatment method is reduction precipitation method.Ultimate principle is to add reductive agent under acidic conditions in waste water, with Cr ⁶⁺Be reduced into Cr ³⁺, and then add lime or sodium hydroxide, make it generate chromium hydroxide precipitation under alkaline condition, thereby remove chromium ion.Reduction precipitation method has advantages of that one-time investment is little, working cost is low, treatment effect is good, operational administrative is easy, thereby is used widely.But when adopting this method, the selection of reductive agent and the control of processing condition are vital problems, and the contriver has drawn effect processing parameter preferably to this repetition test.

Summary of the invention

The object of the present invention is to provide a kind of method of processing waste water containing chrome, the method equipment is simple, effective.

Realize technical scheme of the present invention: a kind of method of processing waste water containing chrome, concrete steps are as follows:

(1) first with conditioning agent, the pH of waste water is adjusted to 1-3, conditioning agent is the vitriol oil;

(2) add reductive agent, reductive agent is sulfurous gas, S-WAT, metabisulphite, and sexavalent chrome is changed into trivalent chromium;

(3) add NaOH neutralization, being adjusted to pH is 8.5-8.8, in and the time be controlled at 10-12 min, described NaOH is that massfraction is the NaOH of 5%-8%;

(4) add flocculation agent, stirring velocity 60-80 r/ min, settling time 40-60min, described flocculation agent are polyoxyethylene (PEO);

(5) stillness of night after sedimentation can discharge, and recycles after the solid matter drying of sedimentation.

Method equipment of the present invention is simple, easy to operate, and treatment effect is good, and expense is low, and processing condition are easy to control.

Embodiment

Embodiment 1

A kind of method of processing waste water containing chrome, concrete steps are as follows:

(1) first with conditioning agent, the pH of waste water is adjusted to 1, conditioning agent is the vitriol oil;

(2) add reductive agent, reductive agent is sulfurous gas, S-WAT, metabisulphite, and sexavalent chrome is changed into trivalent chromium;

(3) add NaOH neutralization, being adjusted to pH is 8.5, in and the time be controlled at 12 min, described NaOH is that massfraction is 5% NaOH;

(4) add flocculation agent, stirring velocity 60r/ min, settling time 60min, described flocculation agent are polyoxyethylene (PEO);

(5) stillness of night after sedimentation can discharge, and recycles after the solid matter drying of sedimentation.

Embodiment 2

A kind of method of processing waste water containing chrome, concrete steps are as follows:

(1) first with conditioning agent, the pH of waste water is adjusted to 3, conditioning agent is the vitriol oil;

(2) add reductive agent, reductive agent is sulfurous gas, S-WAT, metabisulphite, and sexavalent chrome is changed into trivalent chromium;

(3) add NaOH neutralization, being adjusted to pH is 8.8, in and the time be controlled at 10min, described NaOH is that massfraction is 8% NaOH;

(4) add flocculation agent, stirring velocity 80r/ min, settling time 40min, described flocculation agent are polyoxyethylene (PEO);

(5) stillness of night after sedimentation can discharge, and recycles after the solid matter drying of sedimentation.

Embodiment 3

A kind of method of processing waste water containing chrome, concrete steps are as follows:

(1) first with conditioning agent, the pH of waste water is adjusted to 2, conditioning agent is the vitriol oil;

(2) add reductive agent, reductive agent is sulfurous gas, S-WAT, metabisulphite, and sexavalent chrome is changed into trivalent chromium;

(3) add NaOH neutralization, being adjusted to pH is 8.7, in and the time be controlled at 12 min, described NaOH is that massfraction is 6% NaOH;

(4) add flocculation agent, stirring velocity 68 r/ min, settling time 55min, described flocculation agent are polyoxyethylene (PEO);

(5) stillness of night after sedimentation can discharge, and recycles after the solid matter drying of sedimentation.

Claims (1)

1. the method for a processing waste water containing chrome is characterized in that its concrete steps are as follows:

(1) first with conditioning agent, the pH of waste water is adjusted to 1-3, conditioning agent is the vitriol oil;

(2) add reductive agent, reductive agent is sulfurous gas, S-WAT, metabisulphite, and sexavalent chrome is changed into trivalent chromium;

(3) add NaOH neutralization, being adjusted to pH is 8.5-8.8, in and the time be controlled at 10-12 min, described NaOH is that massfraction is the NaOH of 5%-8%;

(4) add flocculation agent, stirring velocity 60-80 r/ min, settling time 40-60min, described flocculation agent are polyoxyethylene (PEO);

(5) stillness of night after sedimentation can discharge, and recycles after the solid matter drying of sedimentation.