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Using Bioaugmentation as a supplement to help increase your numbers can help when you are limited by equipment and time capabilities.
It’s always a time and numbers game in wastewater. But, you can usually only change the numbers in this balance. How much time you have is determined and limited by the size of the equipment in your wastewater treatment plant for the hydraulic influent loading. The Numbers is represented by how many bacteria you have present in the system to degrade the incoming organics. The more time you have the less numbers you need in order to achieve your final effluent quality. Then a third variable is added as well; how much loading and concentration of BOD vs just your influent flow.
Using Bioaugmentation as a supplement to help increase your numbers can help when you are limited by equipment and time capabilities. A change in variation of loading and nutrient requirements often makes it difficult to run any wastewater plant. When a change is made at a plant of more than 10%, it is significant to the bacteria. Bioaugmentation addition throughout the plant or even upstream may be necessary to help even out the significant BOD swings in influent flow and loading changes that may vary daily if not hourly.
All of the pieces of equipment in your wastewater treatment plant are interconnected. What you do in the primary impacts the secondary. What you do in the clarifier is returned back to the secondary, so it also can have an impact. Digester and dewatering decant and supernatant are usually returned to the head works so again, they can impact your biological process as well.
Secondary Aeration treatment is basically a Biological “Bug Factory”. You need to grow bacteria to successfully meet final effluent permits. There are no replacements for the biological activity. You can build more equipment, you can use all the chemicals you want, but basically, it comes down to how well you can grow bacteria! All types of bacteria make up activated sludge. The predominant type will be determined by the nature of the organic substances in the wastewater, the mode of operation of the plant, and the environmental conditions present for the organisms in the process. We hear all the time, “my bugs are dead!”, when in reality; the higher life forms have shifted as sludge age increases or decreases. The bacteria themselves are not dead!
In order to view the bacteria present in the wastewater system for monitor and control purposes, samples must be collected. Where, how and when you sample the MLSS or bacteria can make a total difference in how accurate the analyses. One thing to note if you have a municipal wastewater treatment plant- we have run analyses in the morning vs. the afternoon; there can be minor daily changes in your biomass, depending upon the time of day. You can have major changes whether it is just after a weekend, or even if it is just after a major rain. Are you an industrial facility with cleaning and sanitation over the weekend, or are you a municipality with industrial users? These can change your influent loading variations as well.
Keep notes on when you take the sample. Take multiple samples during a normal day just once to see if there are changes in your system. Remember, the bacteria growth cycle can be 20 minutes to 2 hours, so 8-10 hours can sometimes make a difference in how the MLSS looks, mainly the types of higher life forms present. If you get hit with a high loading, 4 hours later, the amount of amoebae, flagellates and higher life forms will change, so keep that in mind. These are your early warning indicators. This also applies to food plants, where the night shift is completely different from the day shift. In order to keep from chasing your tail, try to standardize your sampling. Take samples at the same place and at the same time of day to keep track of trends, unless you know you just got hit by a big spill.
Use your microscope to not only benchmark when things are bad, but good as well. This should be a simple daily test. With practice, this should only take a short time to perform, yet can provide invaluable information about your system and what you may need to do to troubleshoot and change your “numbers”. Since you cannot jump in, see under the water, and really know what is going on in the bottom, pull samples instead and use the microscope to tell you what is going on. Then with a little detective work, you can really pull together what each piece of equipment in your system is doing. This shows how each piece of equipment ties all together and little things here and there can make a big impact.
Higher Life forms or Indicator organisms indicate how well you are beating the time and numbers game. Do you have sufficient bacteria in your system to handle the incoming BOD loading? They are the last to come and the first to leave during upset conditions.
First in your system after your bacteria, you will develop Amoebae. As you get a little older in your system, you may start to develop Flagellates. Free swimming ciliates are the next type of indicator organisms. All of these still indicate you have a pretty young to medium sludge age. Stalked ciliates and Suctorian come next. Rotifers are next in the line of sludge age and indicator organisms. Worms are the last in the line of typical higher life forms present in wastewater.
Obviously if you have a ton of Amoeba and Flagellates, you have a very young system, and should possibly reduce wasting for a short time or add bioaugmentation products to supplement the numbers you have for the present amount of BOD loading. If instead, you have a ton of Rotifers and Worms, you might want to consider increasing wasting short term. How old your sludge age is depends upon also the type of organics you need to break down, also the permit limitations you have. Chemical plants and Refineries usually have a longer sludge holding time as they need to break down hard to degrade compounds. Food plants have simple organics and need less time. Some plants may only have a pretreatment area and need less time as they are paying the local municipality to finish the job for them.
Because every wastewater has a different bacterial population as its biomass, every wastewater has a different floc structure. What is good floc structure in one wastewater may be poor floc structure in another wastewater. It is difficult to tell trends in good or poor structure by looking at a specimen through the microscope only one time. Generally, the more that is known about a particular wastewater, the more comments can be made about its structure. Nonetheless, some characteristics can be examined to determine relative floc condition. Generally, the more firm and compact a floc is, the better it will settle. The more lacy and dispersed a floc is, the less likely it will be to settle. The presence or absence of pin or straggler floc, which can be responsible for high-suspended solids (TSS) in wastewater, is also an important observation when examining floc structures. 98% of BOD removal is from the single celled bacteria (floc formers or filaments) - not your higher life forms as many people think.
What about adding nutrients to your system to keep the biological bug factory running smoothly? If your system is lacking in nutrients, N and P, detrimental filamentous bacteria and Zooglea can grow. Consider adding micronutrients if you constantly have BOD swings at your plant.
A typical loading of nutrients is 100-5-1 of Carbon, to nitrogen to phosphorus in order for optimal bacterial growth. During wide swing loads, nutrients should be increased if you need to supplement. Nutrient deficiency can cause serious problems. It is already harder for the floc forming bacteria to work when high organic instant BOD swings come through, but add the stress of nutrient deficiency and this increases the problem. This creates a climate that is difficult for the floc forming biomass to grow in, but enables filamentous bacteria to take over.
Another typical mistake some plants make with nutrient dosing is the time when they add their nutrients. Some plants slug feed and some use a continuous feed rate. Typically the nutrients should be dosed according to the load. If the largest load is spread out during the day, then feed your nutrients continually. If you get huge swings at the end of the day when the plant shuts down or has high loading from cleanup processes, then increase during that loading period. Remember that the life cycle of the bacteria is 20 minutes to two hours. If you dose a ton of nutrients in the morning and have a short holding time in your system, and the high loading does not hit until the evening, they will not have the nutrients you have loaded. Most importantly, make sure the bacteria are getting the right amount of nutrients at the right time. The addition of Bioaugmentation with the supplemental addition of Micronutrients, along with some process control adjustments should help in aiding the system to shift to optimized conditions to help win the time and numbers game.
Who said treating wastewater was going to be easy?! Everyday there are changes; the loading, the temperature, the weather, broken equipment, etc., so give yourself a hand as you really have a difficult job in running your bug factory.
Call our office if you need help with lab analyses to help you determine the quality of your biomass not the quantity. Remember, filaments can take up 40-60% more volume, so while it may look like you have "more” numbers, in reality you are just taking up more space. All MLSS is not the same. Don’t get too caught up with a traditional MLSS reading. Using the microscope will help to determine the quality not just the quantity of your biomass. A wastewater biomass analyses from our lab would consist of a number of different things… A cover letter including an explanation of the overall health of your system as observed through the sample, plus any suggestions for troubleshooting that might be indicated by the observations noted. The report includes an analysis of the floc structures, the higher life forms and possible filamentous identifications if required. This analysis can help not only show exactly what the health of the system is at a given time, but can also help predict which direction the plant is headed if used daily. It is a tool that can also help prevent critical upsets, or be used as an early warning. In the cases of filamentous problems, staining and identification of the filaments can help with troubleshooting and help avoid costly chemical consumption.
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