Use of Carbon Steel Tank for Wastewater 1

[RJSH]

We are reusing a existing carbon steel tank to hold industrial wastewater of acidic nature ( lower value upto pH 4) for temporaily storage when the treatment system is in upset condition. What are the items to be considered for this conversion. What would be the minimum D.O. to be maintained? What type of interior coating would be the best? What type of mixing system to keep the solids in suspension? Tank = 50 ft diameter, 30 ft ht. above the ground tank. Closed Top.
Any insights from who has worked in such project or who has done such conversion would be greatly appreciated.

 

[Watthour]

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?

 

[bimr]

You need a lining system that is compatible with the chemicals that you are using.

A minimum of 0.5 mg/l of oxygen will be adequate to keep the mixture from going anaerobic (which may offgas).

If settleable and floatable solids are present, the wastewater must be mixed to to keep light solids in suspension (approximately 0.02 kW/m3 [0.1 hp/1000 gal]). Fly ash, carbon slurries and other denser materials require more mixing energy.

 

[sjohns4]

Contact your local reputable coating supplier: Sherwin-Williams, Tnemec, Devoe, etc. for help with the approperate coating, surface prep, and proper application procedures. Being a closed top tank it may not last long with out a good coating. As Bimr said, something like 0.5mg/l would be approperate, which means you'll need some sort of aeration system. Given the liquid level will be variable depth look at Positive Displacement type blowers. A reputable aeration system manufacturer (EDI, SSI, Sanitaire, etc.) can help out with the aeration requirements.