Water treatment unit for the elimination of Chromium VI and Total Chromium in waste water.

- Metal surface treatment

- Tanneries

- Industries

- Concrete batching plant

 

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Description

What is Chromium VI ?

Chromium belong to the series of transition metals.The most common oxidation states are Chromium IIIand Chromium VI. Chromium III is to a certain amount,essential for the body to regulate insulin and glucosemetabolism. Chromium VI is very toxic and doesn’tcome from human activity. There is no Chromium VIin natural state and it’s extremely poorly metabolisedby the human body.

 The effects of a Chromium VI pollution exposure are important and varied:

  • Medical complications (asthma, pharyngitis, bronchitis...)
  • Skin allergy (drying, cracking...)
  • Contamination through ingestion (diarrhea, gastrointestinal cancer...)
  • Impact on the replication and the transcription of the DNA

 

Application fields

Regulatory Framework

The Decree of 1st February 2001 supported by the REACH defines Chromium VI as a CMR agent (Carcinogen / Mutagen / Reprotoxic).

US-EPA sets the value of Total Chromium in water intended for human consumption at 100 μg/L.

WHO estimates that there is a real risk of toxicity starting from 50 μg/L of Total Chromium in water intended for human consumption.

ANSES established a limit value of Total Chromium in drinking water of 50 μg/L and 6 μg/L of Chromium VI (Request No 2011- SA- 0127-2 July 2012).

 

Regulatory framework for concrete batching plant: 

*The decree of 26 november 2011 about general instructions for concrete batching plants, has imposed new discharge standards applicable since the first july 2014: 

Suspended solids < 35 mg/l       pH: 5,5-9,5        Total Chromium < 100 μg/l       Chromium VI < 50 μg/

 

However, we currently find concentration values of 100 to 500 μg/l in waste water from batching concrete plants.

 

 

Unique patented treatment process

Chemical reduction of Chromium VI into Chromium III thanks to a reducing solution based on ascorbic acid (non reversible), absolutely neutral on the environment (patent filed on March 28, 2014): 

  • pH treatment
  • Reduction of Chromium VI into Chromium III thanks to a reducing solution based on ascorbic acid
  • Filtration / adsorption of Chromium III

 

This entire process is summarized in the flowsheet below: 

What is acid ascorbic ?

Ascorbic acid is a weak acid known as vitamin C, a vitamin found in many foods such as: kiwi, broccoli, orange, lemon... It’s an organic acid with antioxidant and reducing properties. The use of ascorbic acid to reduce chromium VI into chromium III in water is absolutely neutral on the environment.

 

A complete range of compact units from 0,5 to 20 m3/h

Option:

  • Buffer tank to smooth the flow and improve the physico-chemical reaction
  • Settling tank for the elimination of suspensed solids
  • pH treatment upstream in order to improve the desorption of chromium adsorbed onto particles

Tailor-made support and services:

  • Operation assistance and supervision of the equipement
  • Sampling and laboratory tests
  • Performances validation
  • Recommandations and supply of the adapted consumable
  • Feedback and optimisation of the equipment