Blackish color Cooling Tower Blowdown

Recent past we observed blackish color in Distilary & Fermentation Cooling towers blowdown water, can you help us to find out what is the exact reason for this.

Attache one photo & Video of the blow down sample.

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Taxonomy

• Cooling Boiler & Wastewater
• Cooling Systems
• Tower
• Cooling Systems
• Cooling Systems
• Cooling
• Cooling tower maintenance and repairs

5 Answers

1. Few things will create a black color and typically most will be related to anaerobic growth and all are not good. 

   If the black is coming from most iron salts, collect some of the material in a test tube and insert a small magnet nearly all black iron salts are magnetic. So if you get a build up of crud on the magnet, Some of it is going to be iron.

   You can also elevate the pH to over 8.2 (very small scoop of baking soda) then add some bleach if it goes red. It is iron.

   I'd start to look at any mild steel water on the shell H/E's  that might be running hot.  It is not uncommon in a system as you have to pull in lots of bacterial food and the bacteria setup growth in the slow/low flow coolers and then you get a massive release of all that crud.

   If it is iron, you have a severe corrosion problem and you need to address that quickly.

   Hope this helps you.

    

   1 Comment

   1. Terry Scheurman gave you the best advise. Fully agree wih her. 

2. Just adding water filtration system before recirculate it

3. 1. Add HCl to this sample of water. Will it dissolve? Will it smell? Will it make bubbles?

   2. Add hypochlorite. Will color change? Make pH acid with HCl (let say < 4) What changes you will observe?

   What pH, iron, COD do you have in recirculating water?

4. With Minral salts algae formation and mismanagement of cooling system. 

5. An excess of mineral deposits in the water that flows through your system can cause black water to emerge from cooling tower blowdown. Magnesium, manganese, and iron are common minerals that build up in your water system over time. When these minerals oxidize—i.e. mix with oxygen and turn black, which in turn causes the water that flows out of your CT to appear black as well. All you need is a water filtration system that removes excess minerals from your water before it recirculate back to system.

   1 Comment

   1. Adicionalmente, aconsejaría revisar si hay condiciones anoxicas, es decir mal olor del agua de la purga, lo que indicaría presencia de materia orgánica, es decir, descomposición de algas