It could be lots of things but you would have to provide more information.
Where does the wastewater that you are treating come from? Is it an industrial process, or municipal?
What are the current operating conditions? For example what is the MLSS , how is the plant performing in terms of effluent quality, what has happened before this event?
White foaming is often related to low MLSS. If the yellow color is related to some form of toxic substance and it wiped out most of the biomass you could end up with a lot of white foam.
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
We are a food processing company , our main products are dairy (UHT , Milk powder) and noodle.
Our influent BOD is around 900 mg/l except in exceptional cases.We maintain the mlss near 4500 mg/l.
We adjust the pH 7- 9.5 .Our normal operating COD of treated water is <20 mg/l and BOD< 10 mg/l ,TSS < 4 .Now the COD has risen up to 40, BOD near 30 and TSS 8.I'm confused with the SV 30 value which is 1200-1500 ml .I think what we find here is dispersed (non settling) growth. What should be done to that?
Normally poor settling is not a problem with MBRs because sedimentation is not required to achieve solids water seperation. This is the role of the membranes. I am also intrigued by your TSS number of 8. Normally MBR plants have very low TSS because the membranes offer extremely efficient solids/ water seperation with very low TSS.
If you have had much better settling conditions then your SV30 of 12-1500 and an increase in COD and BOD i would start by looking at your long term DO levels and air volumes.Has this changed? Has the DO declined? Are your DO instruments being calibrated and maintained correctly? The second thing i would look at is whether there has been a change in process or cleaning in the dairy factory. Is a different chemical being used? Is something being done more or less frequently than before? Has some new process been introduced?
Why do you adjust the pH from 7 to 9.5?
Regards
Ashtree
"Any water can be made potable if you filter it through enough money"
Yes sir , as you mentioned there were some process changes.First thing was we were running only one process blower (6500 m3/h)to aerate the 1500 m3 bioaeration tanks, which gave us 3 mg/l online DO level.But we found out that it was a false reading and now we are running 3 blowers simultaneously .Now we monitor DO by a portable meter which gives us a value near 1.5 mg/l.
The other thing was we have received one bowser of rotten milk (3000 l) without pretreatment directly into the wwtp by the processing section.We were not aware of that until the plant started to change after 3-4 days.
Fortunately now I think we have recovered somewhat.Now the TSS is 3-4 ,and COD 30.
The main things we did was 1. increased the aeration 2. Increased dosing nutrients.
Normally we have been advised that the mentioned pH range is best for microbes.
Thank you
