Skip to main content

Biochemical Oxygen Demand and Coliform Count

Biochemical Oxygen Demand (B.O.D)
  • Amount of oxygen taken up by sewage sample in mg/l or ppm is termed as Biochemical Oxygen Demand.
  • Measure of strength of sewage.
  • Identifies biological decomposable substances and is a test on the activity of bacteria,
  • Presence of oxygen feed on and consume organic matter.
  • Test results are expressed as amount of oxygen taken by one litre sample (diluted with aerated water)when incubated at 20°C for five days. It gauges the effectiveness of sewage treatment process.
  • B.O.D of raw sewage is 300 to 600 mg/litre.
  • I.M.O recommends a B.O.D of 50 mg/litre after treatment.
Coliform Count
  • Coliform organisms are recognised as the indicator Organisms of sewage pollution.
  • Numbers present in sewage are large. Each person contributes between 125 billion, in winter to 400 billion, in summer.
  • Coliform are present in human intestine and presence in water is taken as an indication of the pathogen count.
  • Responsible for Typhoid, Dysentery, Polimyelitis, Cholera disease.
  • I.M.0 recommends a Coliform count of 250/100 ml. of effluent after treatment.
  • It gauges the effectiveness of disinfection

Labels:

Comments

  1. primehealersMarch 11, 2022 at 4:13 AM

    Thanks for publishing such great information. You are doing such a great job. This information is very helpful for everyone. Keep sharing about oxygen concentrator on rent in delhi. Thanks.

    ReplyDelete

Post a Comment

If you have any doubts.Please let me know

Popular posts from this blog

Manganese bronze is not typically used as a propeller material .Why

1. High cost: Manganese bronze is a costly alloy, making it less economical for large propellers. 2. Low strength-to-weight ratio: Compared to other propeller materials like nickel-aluminum bronze or stainless steel, manganese bronze has a lower strength-to-weight ratio. 3. Susceptible to corrosion: Manganese bronze can corrode in seawater, especially when exposed to high velocities and turbulence. 4. Poor cavitation resistance: Manganese bronze is more prone to cavitation damage than other materials. 5. Difficult to cast and machine: Manganese bronze is challenging to cast and machine, making it less desirable for complex propeller geometries. 6. Limited weldability: Manganese bronze has poor weldability, making repairs and modifications difficult. Nickel-aluminum bronze or stainless steel are commonly used for propellers due to their: - High strength and durability - Excellent corrosion resistance - Good cavitation resistance - Ease of casting and machining - Weldability
107 comments
Read more

MAN B&W MC Engine VIT Pump

The pump is basically a jerk type with a plunger moving in a matched barrel, using two helical grooves machined in the plunger to control the end of injection by uncovering spill ports and causing the discharge pressure to drop rapidly, thus causing the needle valve in the injector to close. Oil is supplied to the barrel via the spill ports and a suction valve. The suction valve, situated at the top of the barrel opens when the pressure in the  barrel falls below the supply pump pressure; i.e. during downward stroke of plunger, while spill ports are covered by plunger. Replaceable erosion plugs  are fitted in the pump housing opposite the spill ports. The high pressure oil, spilling back, as the edge of the helix uncovers the s...
Post a Comment
Read more

Main engine interlocks

Interlocks are provided so that the engine can be started or reversed only when certain conditions have been fulfilled. When there is a remote control of engines, it is essential to have interlocks. This reduces the possibility of engine damage and any hazards to the operating personnel. Turning gear Interlock . This device prevents the engine from being started if the Turning gear is engaged. Running Direction Interlock . This prevents the fuel from being supplied if the running direction of the engine does not match the Telegraph. Starting Air Distributor in end position . This prevents starting from taking place if the shifting of the Distributor has not been completed. Main Lube. oil pressure, Piston cooling pressure, Jacket water pressure, and important parameters must be above the required minimum. Auxiliary Blower Interlock . The Auxiliary Blower is provided in case of Constant pressure turbo charging. Air Spring pressure Interlock . In case of the present generation...
9 comments
Read more