WWTP Sodium Hypochlorite System

[rebuh72]

Does anyone have experience with piping desing for sodium hypochlorite? I'm concerned about off-gassing in the pipe and was looking for creative solutions. Also, what coatings have people used for steel pipe in this service?

Thanks

 

[envscout]

Ran across a thermoplastic coated pipe some time ago but do not know about the chemical resistance. Was traded under the name Alvenius but not sure where you would get it.

 

[bimr]

Search this site. This question has already been asked and addressed.

 

[sewerfix]

We had problems of hypo gassing in the pipelines at a small installation causing the diapham pump to not pump liquid until the gas lock was pasted.
The issue is well known to pump suppliers and hence we had to replace the pump head with one that included an automatic de-gassing head. A bleed line was then run back to the supply tank.
In the end it proved successful.
As for gassing down stream of the pump, thats another story.

 

[SanEnr1]

There are too many variables to consider in NaOCl designs to address in this forum. bimr is correct; check historical postings. You may also want to search on the Water Environment Federation website (

http://www.wef.org).

In systems that I have designed and maintained, I try to keep the source as close to the addition point as possible. Try to introduce the NaOCl as neat product rather than using carrier water to reduce the chance of calcification in the distribution lines. I prefer to use peristaltic pumps in these applications when the design allows. Try to use a flooded suction on the pump whenever possible or pay very close attention to the NPSHr. Do not use any stainless steel in your design. Finally, consider the owner's NaOCl specifications; they should be very specific regarding contaminants, age of product and temperature.

 

[corrosionman]

Rebuh72 I am very sure that rubber lining for the steel pipes is a perfect solution ( although such lining is my business I,m not trying to sell you anything) A good quality ebonite will survive for very many years. Call back if you do not get the advice you really need. Regards DW
( sales@clevelandcorrosion.com )

 

[sam01]

Utilize CPVC schedule 80 piping, they also use cpvc ball valves where the ball of the valve is drilled on one side to prevent gassing of the hypochlorite. I have used CPVC piping in the past which works well, also use compatible adhesives for installation of the piping.