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Recent content by Watthour

  1. Watthour

    More SCADA weakness?

    This is an overview: https://energy.gov/sites/prod/files/oeprod/DocumentsandMedia/18-Security_Metrics_for_CS.pdf The National SCADA Test Bed Standards Report outlines the common industry standards and guidelines. From what I know, the requirements from DOE do not dictate the on-site systems...
  2. Watthour

    More SCADA weakness?

    I don't believe I wrote that it was 'internet" or even "wired" in the original post. I've set up wireless SCADA in the past, and wireless I/O, and wireless data point transducers for single inputs. Some have been cellular, some have been satellite, and some have been line-of-sight. I'm...
  3. Watthour

    More SCADA weakness?

    http://www.cnn.com/2017/04/08/us/dallas-alarm-hack/index.html This is one of the more publicized events. It's possibly only the proverbial tip of the iceberg.
  4. Watthour

    Poultry Processing Waste Water Treatment

    At the risk of piling on, removal of the FOG before release to any field will be essential. Bimr made that adequately clear a couple posts ago. Perhaps I'm reading this differently, but I understand that the 500G of CIP waste will be in addition to normal processing water. Is that correct...
  5. Watthour

    COD Removal

    My specific point was to caution against using general assumptions. The mass balance for solids is clear, and while assumptions such as that may be true with biosolids the OP did individually mention COD and BOD separately as load for the plant, and not simply biosolids as the sole source of...
  6. Watthour

    Motor Circuit Surge Surpression

    Consider installing a PTC thermistor current limiter (Ametherm) in the circuit to limit inrush. Several are available suitable for that current range at 120V (or higher). I've been installing them routinely in larger control transformer applications (up to 5.0kVA and 460V) with good success to...
  7. Watthour

    soft starter tripping issue

    Is the drive directly firing the stator or is there some DU/DT or other filter in the circuit?
  8. Watthour

    COD Removal

    While much of what was offered is generally true, the answer lies within the analysis of the waste stream. Depending upon the contents, high COD may or may not contribute to solids production. Consider a recent SBR design I completed where the CBOD5 equivalent was over 20,000 ppm and TSS was...
  9. Watthour

    Fine Air Bubble Diffuser

    The basis of the above is mostly correct, However, I would point out that the aeration mixing rates may be incorrect in general applications. 20 CFM/ MCF is the 10-States Standard for municipal waste, and 30 CFM/MCF is required in municipal digesters. It is likely that TCEQ will adopt those...
  10. Watthour

    High COD in treated effluent

    Aahmed. It seems that the clarifier(s) may be upset from young sludge (low SRT) and possibly insufficient F/M. It may be actually made worse by the excessive D.O. If you sample the MLSS for nocardia or similar filamentatious microbes, what is present? Is the system using a full MLE...
  11. Watthour

    Use of Carbon Steel Tank for Wastewater

    What kind of acids are present? What temperatures are expected? What are the dimension of the top hatch? Maximum/minimum liquid depths? TSS and size of particles? What is the Treatment scheme following this EQ tank? What residence time in the tank?
  12. Watthour

    Siemens TI 315 programming software

    Are those things STILL around? It seems that everyone had a version of that (in a different color). They were not a bad solution for a small project, so long as the I/O was isolated from noise and EMI, I only ever programmed those with the plug-on programmer module, but they can work.
  13. Watthour

    Allen Bradley PLC

    A 1400 can support up to seven expansion modules for digital, relay, and analog inputs and outputs. It can also support EtherNet/IP and other (serial and CAN bus) protocols to enable a link to HMI panels, whether PV+ or other manufacturer's panels. If not a lot of processing power is required...
  14. Watthour

    Effluent Nitrogen in an Activated Sludge WWTP

    With some hesitation I would disagree with the statement that only 30-40% removal can be achieved with dedicated denitrification. I have MLE designs operating which take TKN from 55 mg/l to below 5 mg/l in the effluent - Without using flocculants and tertiary filtration. As we all know...
  15. Watthour

    Rotary Encoder

    You can measure the can dimensions, shaft dimensions, mounting means, and either check your equipment documentation or the setup of the control system to determine the correct PPR or disassemble the encoder and count the marks in the prism to determine PPR, although the latter method may require...
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