New Wastewater Plant Start-ups or starting up after a shutdown

What are some of the things that you need to be critically aware of when starting up a new wastewater treatment plant and what are some of the problems that may occur?

Obviously, the main things to be aware of are the manufacturer's design specs, following all standard operating procedures, and making sure the "Critical 5" are met.

What the engineers don't tell you sometimes is that you cannot always start a new wastewater plant immediately at full-blown speed. This is probably what will happen if you do. . .. . .. High loading and young bugs do not mix well without lots of room to grow..... You will get some serious white billowy foam! You will also have a very high level of turbidity and TSS. BOD levels will still be pretty high in the final effluent.

HHere is a winery what was just starting up a brand new wastewater plant. There were at least 5-6 feet of foam billowing out the top of the aeration basin, out over the top, all over the ground and even out the overflow spout!!!!

There was foam in the sumps, the drains, in the EQ tank and in the final effluent holding tank. Anywhere the bugs could grow, they did and quite happily as you can see by the evidence of crisp white foam.  Turns out the winemakers had predicted BOD's of 4-8000 BOD but at the time of the start up of the new plant, they sent down anywhere from 16,000 to 100,000 BOD. A huge change in loading. Winery wastewater is like candy to the bacteria, simple carbons. With more than enough air, nutrients, temperature and a great food source, they grew extremely fast.  So fast that tons of foam was generated and spilled up and out of the system./p>

There was even foam coming out of the manhole.

When the bacteria are in a high growth phase and young, there almost always is crisp white foam. With a new wastewater treatment plant start up, in this case with BOD's as high as 20-30,000 and simple sugars from a winery, the bugs were growing like kids in a candy store. During a start-up the levels of the aeration basin must be only at about 1/3 to one half full for the first few days in order to allow room for the foam. As the foam starts to change colors from a crisp white foam to a lighter tan and then to a nice brown color, the levels of the basin can slowly be filled higher to half, 3/4 and then normal operating height. You can always cheat, and add bacteria supplements at a higher dosage to speed up the process along with micronutrients.

Remember that it is always a time and numbers game with bacteria in wastewater treatment. How much time, how many numbers and how much food is there to degrade. The more food, the more time or numbers is needed. Since you are limited by time due to the fixed space allowed in the pieces of equipment in the system and a fixed holding time, the only way to win the game is to change the numbers. You can decrease wasting, play with your RAS or use bacterial supplements.

Here the foam is not as white and is starting to turn a light tan or brown. Less foam is present and the biomass is starting to get a bit older. More floc structures are present and higher life forms are starting to show up.

Here is foam from a papermill wastewater treatment plant that is still young, but not in the start-up phase. You can see the difference in the color of the foam. Definitely light brown.

Foam changes color as the bacteria age.

This is a wastewater plant at a winery in Australia, you can see by the amount of foam on the picture on the right vs. the one on the left, which was the younger phase with the higher BOD and F/M ratios. Always look at the foam, it can tell you what is going on. Correlate that to your Settleometer data, and your microscopic and you should be able to fine-tune your wastewater treatment plant.

This is from the wastewater treatment plant at a winery in Napa during the first week of start-up. There is starting to develop a MLSS as you can see by the solids on the bottom of the Settleometer. There are still tons of single celled bacteria evident by the cloudy, turbid water. A few days off still from having a good biomass and less foaming.  As each day goes by, you can see the MLSS build. You can increase the level of loading and raise the aeration basin levels a bit each day as the foam slowly subsides with more and more MLSS building up.

This photo on the left is from a chocolate wastewater treatment plant. The MLSS has definitely caught up to the loading. Almost too much MLSS and time to finally start wasting. Free swimming ciliates, and well-defined floc structures were present in this sample. Clear supernatant was present. Eventually, this plant was able to achieve 15-20 TSS and 30 BOD with a loading of 4-8,000 COD at times.

This photo on the right is from a papermill with two aeration basins that had  light brown foam. As you can see, the tank on the left had D.O. problems, evident by the instant floating of the solids in the Settleometer to the surface.

Many wastewater treatment plants like to use antifoams. Actually, as a band-aid in a pinch they work, but what they really do is remove the air, which is critical to the bacteria in a high growth phase, so it takes longer for them to get out of the high growth phase and they also can add extra BOD to the water, which can cause an even younger sludge, nutrient deficiency and ever more foam long term, so it is a catch 22 using antifoams.

Alternatives to chemicals are to use mechanical means to spray the influent or clean water over the foam and use gravity to compress the foam. Using the influent is the easiest, since you are not diluting the tank with extra water and shortening the retention time in the systems in you use additional clean water. Bioaugmentation also is easier, and cheaper to use than antifoams or chemicals and is more natural.

Alternatives to chemicals are to use mechanical means to spray the influent or clean water over the foam and use gravity to compress the foam. Using the influent is the easiest, since you are not diluting the tank with extra water and shortening the retention time in the systems in you use additional clean water.

Simple sprayers can be made or purchased. This was used onsite with just a submersible pump, and some PVC piping.

This was a trial for a chocolate factory wastewater treatment plant and again, influent spray was used to knock down the foam. Side benefits of doing that are it kept down the temperature a little bit, circulated and mixed the aeration basin and helped add a little bit more D.O. to the system as opposed to using chemical antifoams.

Some wastewater plants use spray for older plants with foaming as a physical control method instead of using antifoams.
This was not a start-up but a municipal wastewater plant that has problems with filamentous bacteria causing foaming. Influent is used by sprayers on the sides of the basins to knock down the foam and control it while process changes are being implemented

If you have an activated sludge wastewater plant, many times minor process changes coupled with close monitor and control of the biomass can help quicken upset recovery or just increase process efficiency. Not all wastewater plants need biological additives. Some just need to improve the "critical 5" parameters.

Some wastewater treatment plants have constantly changing influents.  No matter how great a control they have, their biomass is in constant flux.  Sometimes adding a biological product or micronutrients can help stabilize and increase the efficiency of the biomass.

Bioaugmentation Benefits:

Key Benefits:

• Increased BOD and TSS removal
• Reduction in polymer consumption
• Decreased environmental liabilities
• Increase in system reliability and efficiency
• Increased Sludge Reduction/Reduced solids handling costs

Biological Products By Activation:

• Activated Sludge systems
• Ammonia cultures for nitrification
• Bioblocks  for lift stations and hard to reach spots
• Collection System-Sewer and Drain Cultures
• Micronutrients
• Grease Control & Liftstation Maintenance
• Lagoons
• Lake, pond and river remediation
• Click here for Additional Products and Formulations

**Bioaugmentation Programs include technical support, computer based training and long term programs include occasional complimentary Wastewater Biomass Analyses of your system.

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