slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Original, impacts, abatement and management PowerPoint Presentation
Download Presentation
Original, impacts, abatement and management

Loading in 2 Seconds...

play fullscreen
1 / 14

Original, impacts, abatement and management - PowerPoint PPT Presentation


  • 70 Views
  • Uploaded on

Chromium. Original, impacts, abatement and management. Content. 1. Original and Impact Chromium emission through industry go to air, water, soil (region matter) Human health effect 2. Management and Abatement Regulation (emission standard) Source reduction Treatment.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Original, impacts, abatement and management' - snowy


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Chromium

Original, impacts,

abatement and management

slide2

Content

1. Original and Impact

Chromium emission through industry

go to air, water, soil (region matter)

Human health effect

2. Management and Abatement

Regulation (emission standard)

Source reduction

Treatment

chromium chemistry

1. Original and Impact

Chromium Chemistry
  • Chromium can exist in oxidation state ranging from -2 to +6
  • Chromium most frequently found in +3, +6
slide4

Industrial Sources

US EPA defines 27 industrial sources of Chromium

  • Textiles
  • Electroplating
  • Organic chemicals
  • Inorganic chemicals
  • Petroleum refining
  • Iron and steel manufacturing
  • Nonferrous metal manufacturing
  • Steam electric
  • Ferroalloy
  • Leather tanning and finishing
  • Rubber
  • Timber products processing
  • Metal finishing
  • Nonferrous metals forming
  • Mineral mining
  • Paving and roofing
  • Paint formulating
  • Ink formulating
  • Gum and wood
  • Carbon black
  • Battery manufacturing
  • Coil coating
  • Porcelain enameling
  • Aluminum forming
  • Copper forming
  • Electrical and electronic components.
  • Asbestos
slide5

Impacts

Emission pathway

Atmosphere: mostly as fine dust, particles

as Cr+6 from electroplating

as Cr+3 from combustion, ore processing,

settle over land and water.

Surface waters: Electroplating

leather tanning, and

textile industries

Most Cr(+3) insoluble and settle down

Cr (+6) soluble but then reduce to Cr (+3)

Soil: Disposal of chromium- products, coal ash from electric utilities etc…

Cr (+3) mostly as insoluble carbonate and oxide immobile

Its solubility may increase when organic matters available

slide6

Human health impact

  • Chromium (III) is much less toxic than Chromium (VI) , major target organ = respiratory tract by inhalation exposure

Acute effect

      • Inhalation: - Irritation and ulceration of the nasal septum

- Respiratory sensitization (asthma) etc.

      • Ingestion: - Gastrointestinal effects (abdominal pain, vomiting, and hemorrhage)

- Affect kidney & liver function etc.

      • Dermal contact: Skin burns etc.

Chronic effect

      • Inhalation: Perforations and ulcerations of the septum,

bronchitis, pneumonia, asthma, etc.

      • Ingestion: Gastrointestinal effects etc.
      • Dermal contact: Contact dermatitis, sensitivity, and ulceration

of the skin etc.

Cancer risk:EPA has classified chromium (VI) as a Group A, known human carcinogen by the inhalation route of exposure.

slide7

2. Management and Abatement

Regulation and standard

AMBIENT AIR QUALITY STANDARD US EPA

  • The maximum 24‑hour Total Chromium concentration at any location≤ 0.3 µg/m3
  • The annual geometric mean of the Total Chromium concentrations at any location≤ 0.05 µg/m3

WATER QUALITY STANDARD US EPA

  • Drinking Water (MAC) ≤ 0.05 mg/l
  • Bottled Drinking Water (MAC)≤ 0.05 mg/l

SOIL QUALITY STANDARD US EPA

  • For habitat and agriculture≤ 300 mg/kg

NOTE:MAC= Maximum Allowable Concentration

These standard only used for Hexavalent Chromium

slide8
AIR EMISSION STANDARDUS EPA

Regulation and standard

WASTEWATER EMISSION STANDARD US EPA

NOTE:These emission standard only used for Chromium Plating Industry

slide9

Source reduction

Recycle

Treat

Dispose

Pollution Prevention

Source reduction

Product change

Process change

  • Input material changes
  • Technology change
  • Improved operating practice
slide11

Source reduction

Electroplating

Alternative

Nickel plating, Chemical Vapor Deposition, Surface Hardening, Thermal Spraying, Physical Vapor

Drag-out Reduction:

Use optimum temperature, chemical concentration, Use drain board, Space

Chromium recover

Evaporate, Reverse osmosis

Good surface prepare:Surface clean, dry

Process Bath Maintenance:Remove bath contaminant by filtration

etc….

Oil, water, sludge, degreaser

Water, heat caustic soda,

Degrease

Alkaline Water

Water Rinse

Water

Water, NaOH, heat

Anodic Cleaning

Waste water

Wet

scrubber

Mist of Cr+6

Water, Chromic acid, sulfate, fluoride,

Chromium bath

Waste water

Waste water Cr+6

Sludge

Rinse 1

Water

Waste water Cr+6

Rinse 2

Waste water Cr+6

Water

treatment technologies
Treatment technologies

Wastewater

  • Physical treatment

Membrane technologies, carbon adsorption, filtration, ion exchange and sedimentation etc,.

  • Chemical treatment

Chemical oxidation, chemical precipitation, chromium reduction, coagulation and flocculation.

  • Biological treatment

Using specific microorganisms

Air(mist, dust)

Using wet scrubber

  • Sludge (management as hazardous waste)
    • using precipitation with lime as reducing agent
    • incineration : Cr(3) to oxide form
treatment technologies1
Treatment technologies

Chemical precipitation

  • Conversion of Chrome from Cr (VI) to Cr (III) that is insoluble at higher pH levels and easy to remove from water (by precipitation or physical / chemical methods).
  • Using SO2 , NaHSO3 , Na2S2O5 , etc. as reducing agents

Stage 1:

3SO2 + 2H2Cr2O4 + 3H2O Cr2(SO4)3 + 5H2O

Stage 2:

Cr2(SO4)3 + 3Ca(OH)22Cr(OH)3 + 3CaSO4

slide14

Treatment technologies

Chromium waste treatment using

chemical precipitation in Electroplating industry