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| | | Supreme Being
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| Over the past six months we've seen the molybdenum concentration in the sludge cake increase from 20 or 30 mg/kg (I think that's the correct units) to above the EPA ceiling limit of 75. In fact, we're over 100. We have been searching for possible sources, including cooling tower blow down (checked with the contractors who handle most of the county's cooling tower maintenance), odor control chemicals, and potable water. We only have about a dozen industrial users, and none of them appear to be using molybdenum products. Anyone got any other ideas??
David |
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| | | Supreme Being
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| David:
It could be coming from something like a vehicle lube or service-type of business, if the Mo is leaching out of grease or oil where it's used. Another possibility is electronics manufacturing, recycling, etc. Here's from Wikipedia:
The ability of molybdenum to withstand extreme temperatures without significantly expanding or softening make it useful in applications that involve intense heat, including aircraft parts, electrical contacts, industrial motors, and filaments.[7][5] Molybdenum is also used in alloys for its high corrosion resistance and weldability.[4][8] Most high-strength steel alloys are .25% to 8% molybdenum.[3] Despite being used in such small portions, more than 43 million kg of molybdenum is used as an alloying agent each year in stainless steels, tool steels, cast irons, and high temperature superalloys.[4]
Because of its lower density and more stable price, molybdenum is implemented in the place of tungsten.[4] Molybdenum can be implemented both as an alloying agent and as a flame-resistant coating for other metals. Although its melting point is 2623 °C, molybdenum rapidly oxidizes at temperatures above 760 °C, making it better-suited for use in vacuum environments.[7]
Molybdenum disulfide (MoS2) is used as a lubricant and an agent. It forms strong films on metallic surfaces, and is highly resistant to both extreme temperatures and high pressure. Sodium molybdate is a bright orange pigment used with ceramics and plastics.[5] Molybdenum trioxide (MoO3) is used as an adhesive between enamels and metals.[9] Molybdenum powder is used as a fertilizer for some plants, such as cauliflower.[4]
Also used in NO, NO2, NOx analyzers in power plants for pollution controls. Apparently, at 350 degC the element acts as a catalyst for NO2/NOx to form only NO1 molecules for consistent readings by infrared light.
Jeff Naumann
(310) 540-0045
FAX (310) 540-0337
http://www.jeffnaumannassociates.com/ |
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| | Update: Molybdenum problem was traced back to the ASR wells at the County water plant. |
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Supreme Being
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| | ASR? How was the moly involved? |
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| | Not sure how it got there yet. Late last year they began seeing increased levels of moly coming from the potable ASR's. |
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Supreme Being
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| | | Junior Member
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| Aquifer Storage Recovery Well...I would assume.
http://www.asrforum.com/fatestudy/what.html
Still curious about what Mb is doing there...perhaps that's a discussion for another forum? |
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