Review of the coagulant dosing Aluminium, Ferric or Calcium or magnesium or combination of them should be the first line of thought. Chlorine application is typically not the answer as it can be more detrimental to the good bugs and inefficient at the pH of the process. And of cause your polymer supplier has not tweaked their product formula a lot recently!!!
You may need to investigate adjusting the sludge residence time and the return/recycling rates if a solution is not otained.
without specifically knowing the WWTP its hard to be more specific but from my experience WWTP operation who have had biological pain have nearly always benefited significantly from an independent audit by an experienced bio reactor consultant.
M parvicella is a typical foaming causing bacterium, but it has some weak points, that you can use to get read of it. 1) normally it affects doemstic plants and it increases dramatically in winter when the temperature drops below 15,0 °C 2) you must avoid to tackle the problems when its level in activated sludge is too high 3) Collect the scum and dispose it (never send it back in the plant) 4) Aluminum polycloride is effective, as Muna already said (and it precipitates phosphorus as well). 4) The basic strategy is in monitoring the bacterium presence since summer and intervene with Aluminum PC, or dose it continuosly (reminding to alternate with iron chloride (if you use it) to avoid acclimation phenomena. Many positive experiences have been recently collected in this IWA Book:
Please go for MBR plant this is better option to control more than 99.9%bacteria.And also you have take care about pretreatment flocculants quality and prescreening it should be less than 2mm for MBR.
What is the WWTP processing? Is it a domestic sewage plant or is it an industrial or food or dairy plant? You may assume that the oxygen levels are good because you can measure oxygen levels at the surface, but oxygen may not have transferred well into the water. If there are areas of poor mixing, poor oxygen transfer, then Microthrix may develop. What are the MLSS levels? It is very difficult to provide general advice without looking at the plant itself, its loadings and microscopic examination to determine what else is present.
Dosing with aluminium salts (3.5 g Al/kg MLSS. day). Up to now, this is the only method that has a "guaranteed" effect and which hardly ever negatively influences the desired treatment results. However, a reduction in the average floc size must be taken into account.
What type of WWTP is this? Generally i have found that M Parvicella manifests itself in systems with very long MCRT's and low F/M ratios. I have also seen that while you may think DO in your biological treatment tanks is the issue, the "septic conditions" that can sometimes cause it are actually found in the upstream collection and treatment steps (ie organic acids being developed in a septic tank or septic layer of a tanks). Look at trying to reduce your MCRT and F/M ratios first and investigate your upstream equipment and holding tanks
Will use hydrogen peroxide, rather than chlorine or sodium hypochlorite with a no CAPEX Rapid Response Turn-Key Solution. If interested, please simply give me a call. USP Technologies is part of the Danaher Umbrella of companies, and we have over 22 years treating this exact type of problem with an unbelievable track record for success. Sean L. Roop 239-989-3581. Please take a look at my LinkedIn profile as I have 28 years of experience with biological systems in industrial wastewater. Trust me when I say that this is a far better approach to solving your issue, and it can be done quickly. We will respond in 24 hours and the potential is there to be up and running the system treating for filaments without the loss of nitrification. Since this is one of our main areas of focus, it doesn’t get much better than what we offer. And there’s really no one offers what we do the way we do it. In fact, that’s why I joined this company. I had never seen anything like it prior to 2003, when they came in to a very bad situation and solved it almost immediately in a refinery that was one violation away from the State taking control. That would have caused them to lose almost 100,000 barrels per day in production. USP really is unbelievable at this. It is certainly worth a phone call, and all of the upfront testing and engineering is free. If, we can’t solve it, then I will pursue a different career. That is how confident
Maybe the problem could be an incorrect balance of the biological reactor in term of nutrients. Parvicella filamentos is a typical situation of law charge inlet and winter time.
oxidations, polymers are not a final solution, can help but the problem keeps serious.
Filamentous bulking is well known phenomenon and several techniques to address it are available under "bulking" "anti bulking" "filamentous bulking" keywords on the Internet. Immediate "symptomatic" solution could be as simple as step aeration, mechanical foam scraping, increased disposal from SS and RAS chlorination Root solution should come from feed analysis (toxic substances inhibiting correct floral inoculum and development), micronutrients misbalance (lack /excess of some basics) or simply poor ETP design (very low F/M, MLSS and MLVSS...) with respect to real feed. HTH
May I ask how much is the wastewater temperature in the activated sludge tanks, if you have measurement there? Do you detect long filaments or shorter ones? Do you have EBPR system and/or do you have any chemical removal technique to decrease phosphorous content?
This year the average temperature was 15 ° C during the winter months (Jan, Feb), rising to 16-17 ° C in March and April, and starting May exceed 20 ° C; the highest temperature was recorded in August, is 26 ° C, then decreasing to values close to 20 ° C, where it was at that moment.
The length of the filaments is variable.We detected long and also short filaments.
Thank you for answering the temperature distribution in time. I have some extra question for your problem:
Do you have M. parvicella during summer term as well?
Do you have EBPR system and/or do you have any chemical removal technique to decrease phosphorous content? Also a good question about the SRT or MCRT?