The authoritative public forum
  for Metal Finishing since 1989
  

  -----

General waste water treatment directions for someone who needs plenty of advice.

Hello, I was interested in any information I could receive on the proper process steps to treat plating waste streams coming from three separate sources. Two are plating processes, a rack and a barrel plater. The other is a coating line for phos. coat and wash purposes. I just need a little trouble shooting information on how to keep clear water coming out of our system. We have had problems with the Clarifier and every area of the Waste Treatment System. Our clarifier is doing about 45 GPM, and is having trouble doing its job. The final result is a sludgy, slightly organic mixtures depending on the quantity of lime and other chemicals added.If there is a tried and true formula as far as GPM, comparative to addition of acid and lime(or any other neutralizer for that matter) please let me know. I have asked for advice in the past and had plenty of good advice given. To those who replied, thank you.

James D. Browning
- Oxford Mississippi
1999

---

It's not 1974 anymore, when this industry was just getting geared up in wastewater treatment, and flawless compliance (or nearly flawless) is mandatory. So it really is too late for trial-and-error. Your people could attend training sessions on operation of treatment systems, but my personal suggestion would be that you hire a local consultant to immediately bring the system into proper operation and train your people.

For the simplest version of a waste treatment system, some of the things you need to consider are: chrome-bearing wastes require reduction to trivalent form, cyanide-bearing wastes require oxidation to destroy the cyanide, and then all of the wastes can be combined together for pH adjustment and clarification. However, you also have concentrated dumps, and these--especially the alkaline cleaners--are very bad actors in your clarifier because cleaners are deliberately designed to resist clarification. Treating strippers is almost surely a no-no.

Also, you need to examine all your processes and see if any of them employ chelators or other problematic components. The cleaners are an obvious target, as are any ammonia-based processes, any electroless nickels or other electroless processes.

Then you need to minimize water flow through better rinsing. Obviously you haven't described the size of your clarifier, but most are very optimistically rated by the suppliers. It well might be that you won't achieve good clarification until you reduce water flows. Good luck.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1999

First, thanks to Mr. Ted Mooney. You have been very helpful and patient.As I stated, I'm not the pro or an engineer, but I would like to help my plants Waste Water Treatment to run smoother. I have asked the Engineers to give me a general rundown of the system we have for our Waste Water Treatment and explain in detail (ph levels,GPM being ran, chemicals added etc.) the process we are following.I'll try to submit this to the hotlist very soon. Maybe you could give some advice to show us where we are going wrong. I informed the proper people of your consulting options and they are looking into possibly using your firm. Second, another problem has surfaced in our rack system. We are having possible organics growing along the walls of our Caustic cleaner tanks. The only drag in would be the smallest amount of rust inhibitor(light oil). We use METEX E-1726 and 103 caustic cleaner. Could the temperature or oil have something to do with this? And could this be part of our Sludge ! problem in WWT? Again thanks for all you advice, it is a big help.

James D. Browning
- Oxford, Mississippi
1999

---

Hello,

I run a .030 MGD extended aeration activated sludge oxidation ditch ww plant. I have been running this plant since 3/10/99. So far it has met it's limit exceeding well. It is a .045 MG ditch. It had only 3 aeration discs when I started. However, when warm weather came I had trouble maintaining a DO over 1.0 mg/l so I added a 4th disc. This has helped bring my DO up to a range of 2 - 3 mg/l. Bug life is good. Many free swimmers but no stalked ciliates. Like I said the effluent is meeting limit very well. The problem I have is floating sludge on my clarifier(in the center of the ditch). I have altered my aeration pattern several times. I do not want to on/off too often as it will harm the aeration drive unit. Some mornings when I get to the plant, the clarifier is entirely covered with what I call "pudding" sludge and is difficult and time consuming to break up. I usually clean the clarifier after wasting. This drops the level in the ditch and clarifier and prevents any loss of solid over the weirs as I clean the clarifier.

Can you advise me of any solution(s)to this problem?

Regards,

Wallace Jones

Jones, Wallace
Patrick Henry Correctional Unit 28 - Ridgeway VA
1999

WE are using sludge contact clarifier at a inlet flow rate of 30 to 40 m3/hr. The problem I am facing is we are not able to get any floc and the bed is not forming (we lost our bed around one and half months back). The TSS for river water is below 15 but the colour of water is very dark, our dissolved oxygen in river water is below 1 ppm and heavy organic load (dissolved)is suspected. WE have demineraliser after pretreatment process, unless I get good clarified water free from microorganisms, my resins will be damaged within days. First set of resin got damaged within a year (usual life is five years). How do I remove the colour and organics (dissolved)? How to form the bed? Pretreatent chemicals are polyaluminium chloride pack of betz and polymer.

Kanika Farzana
(365 MW Combined Cycle Power Plant) - Bangladesh
2002