Unit 8: AP Environmental Science Faculty Lecture with Professor Peter Strom

Summary

Highlights

• Professor Peter Strom shares his passion for the fascinating world of sewage biology. 🔍
• The origin story of Rutgers' environmental department is linked to a fly issue at a sewage plant. 🦟
• Sewage treatment plays a critical role in reducing child mortality rates worldwide. 🌍
• The 1970s Clean Water Act was a game-changer for sewage treatment infrastructure in the U.S. 🏗️
• Sewage treatment systems function as microbial ecosystems, offering unique research opportunities. 🔬

Key Takeaways

• Biological treatment of sewage is a pivotal aspect of environmental science, directly impacting public health. 🚰
• Rutgers University's Environmental Science department owes its origins to a sewage-related problem in 1920. 🎓
• Modern sewage treatment employs interdisciplinary scientific methods to tackle complex problems. 🧪
• Secondary and higher levels of sewage treatment are mandated to ensure safe water discharge in the U.S. 🌊
• Recycling resources from wastewater is an emerging trend, offering ecological and economic benefits. ♻️

Overview

Chapters

• 00:00 - 01:30: Introduction to Professor Peter Strom and Sewage Treatment In this chapter, Professor Peter Strom from Rutgers University introduces himself and the topic of biological sewage treatment. He acknowledges that sewage treatment might not be the first topic that comes to mind when thinking about environmental science. Nevertheless, he aims to convince the audience of its importance and interest. He provides a brief introduction before delving deeper into the subject.
• 01:30 - 03:00: Department of Environmental Science at Rutgers The Department of Environmental Science at Rutgers, where the speaker belongs, recently celebrated its 100th anniversary. The department's origins trace back to a fly infestation issue at a sewage treatment plant in Plainfield, New Jersey. The flies, known as psychotidae, are smaller than houseflies and have a distinct appearance reminiscent of B1 bombers.
• 03:00 - 04:30: Historic Department Formation and Early Challenges The chapter titled 'Historic Department Formation and Early Challenges' describes unexpected consequences and challenges encountered during the early days of a sewage treatment plant's operation, where flies—referred to as filter flies or urinal flies—became a significant nuisance. These flies formed large clouds around the plant, leading to complaints from neighbors and discomfort among the workers. The issue was so pervasive that workers would ingest flies while speaking. This narrative serves to highlight early operational challenges that required mitigation efforts.
• 04:30 - 06:00: Interdisciplinary Approach and Modern Challenges In the chapter titled 'Interdisciplinary Approach and Modern Challenges,' a scenario is depicted where a group of scientists at Rutgers, the land-grant college for New Jersey, were tasked with solving an agricultural problem. The problem involved a fly issue affecting crops that tasted bitter and not very good. Due to the successful outcome of their efforts in controlling this issue, the state decided to establish a dedicated department in the year 1920. This chapter highlights the importance of interdisciplinary approaches in solving modern challenges and the resultant institutional developments.
• 06:00 - 07:30: Sewage Treatment Outline and UNICEF Report The chapter begins by discussing the history and expansion of an environmental department, claiming to be one of the oldest in the world. It mentions a comparison with a similar department in Chapel Hill, North Carolina, which started around the same time. Initially focused on sewage treatment, the department later expanded its focus to include water and air pollution, addressing various environmental issues over the years.
• 07:30 - 09:00: Impact of Water Pollution Control Acts The chapter discusses the impact of water pollution control acts. The transcript reveals that despite various environmental issues such as solid waste, hazardous waste, and climate change, the department has consistently utilized an interdisciplinary approach to tackle these problems. This approach integrates various scientific disciplines, including chemistry, biology, microbiology, physics, mathematics, and statistics, to address environmental challenges effectively.
• 09:00 - 10:30: Evolution of Sewage Treatment and Its Importance The chapter focuses on the evolution and significance of sewage treatment. It combines insights from various engineering disciplines to address and solve issues related to sewage treatment. The author emphasizes their personal focus and the critical importance of this field, aiming to highlight its surprising interest and importance. The chapter promises to delve into the importance of sewage treatment and aims to engage readers by shedding light on its intriguing aspects.
• 10:30 - 12:00: Wastewater Treatment Process Overview The chapter provides an overview of the wastewater treatment process, including sewage and industrial wastewater treatment. It initially covers the fundamentals of treatment with a focus on the biological aspects. The main focus is on the ecology of treatment systems, highlighting its importance. It mentions a UNICEF report about child mortality under the age of five worldwide.
• 12:00 - 13:30: Biological Treatment and Microbial Roles This chapter discusses the role of biological treatment and microbial influences on health, with a focus on children under the age of five. It begins with a stark statistic from 2012, highlighting that 6.6 million children under five died that year, many within the first month of life. Despite improvements, these numbers underscore a persistent risk of disease, such as pneumonia, affecting children who survive their first month. The narrative stresses the ongoing tragedy of childhood mortality and the need for enhanced biological interventions and microbial management to improve child health outcomes.
• 13:30 - 15:00: Microbial Ecosystems in Treatment Plants This chapter discusses the critical role of microbial ecosystems in sewage treatment plants, specifically in preventing diseases such as diarrhea, malaria, and AIDS. It highlights that diarrhea is the second most significant cause of death in children between one month and five years old, with neonatal deaths also linked to poor sanitation. This mortality rate is attributed to inadequate sewage treatment and highly contaminated water, underscoring the importance of effective microbial ecosystems in treatment facilities.
• 15:00 - 16:30: Organisms in Sewage Treatment This chapter discusses the role of organisms in sewage treatment within the context of U.S. water pollution control laws. It highlights the significant impact of the 1972 Federal Water Pollution Control Act and the 1977 Clean Water Act amendment, which were pivotal in advancing efforts to manage and reduce water pollution across the United States. These legislative measures have contributed to significant reductions in pollution, thereby addressing a major cause of death worldwide.
• 16:30 - 18:00: Importance of Microbial Ecology in Treatment Efficacy The chapter delves into the significance of microbial ecology in enhancing the efficacy of treatment processes. It highlights the stringent regulations in the U.S. regarding wastewater discharge, emphasizing the necessity of obtaining permits for both sewage treatment plants and industrial facilities. The importance of adhering to high levels of treatment before discharge is stressed, with a nod to historical practices where primary treatment was the norm, indicating a time when treatment standards were lower.
• 18:00 - 19:30: Common Problems in Activated Sludge Plants The chapter titled 'Common Problems in Activated Sludge Plants' discusses the evolution of wastewater treatment requirements, particularly focusing on the legislative push towards secondary treatment. The chapter highlights the role of federal funding in supporting the construction of local sewage treatment plants, marking this initiative as one of the largest public works projects of its time. The development and implementation of these treatment plants were largely driven by newly enacted laws aimed at improving the treatment levels, underscoring a significant period in environmental management and infrastructure development.
• 19:30 - 21:00: Filamentous Bacteria and Their Impact The chapter highlights the significance of constructing sewage treatment plants in the United States, marking it as one of the largest investments in the history of the world. The scale of investment is compared to monumental feats such as the Egyptian pyramids, the interstate highway system, and sending a man to the moon. This commitment reflects the nation's effort to enhance wastewater treatment and combat water pollution.
• 21:00 - 22:30: Conclusion: Challenges and Careers in Environmental Science The chapter highlights the challenges and career opportunities in Environmental Science. It features the Raritan River, which flows through the New Brunswick campus, as a case study. During a course at Rutgers, a graduate student found only two species in the river: a small freshwater snail and leeches, illustrating the river's specific ecosystem and the biodiversity challenges prevalent in modern environments.

Unit 8: AP Environmental Science Faculty Lecture with Professor Peter Strom Transcription

• 00:00 - 00:30 hi my name's peter strom i'm a professor at rutgers which is the state university of new jersey and what i'd like to talk with you about today is uh biological treatment of sewage it may not have been your your top thing you thought of when you first thought of environmental science but i want to try to convince you today that is still something that's very important and very interesting so before i get into that too much let me just tell you a little bit about
• 00:30 - 01:00 my department so i'm in the department of environmental science at at rutgers and we actually just celebrated our centennial this past year and we our department started because of a fly problem at a sewage treatment plant in plainfield new jersey and uh the these flies are psychotifies they're smaller than housewives pretty neat looking actually look a lot like b1 bombers the ones that i've seen not quite
• 01:00 - 01:30 exactly like the picture that's shown there um but they um they're also called filter flies or actually urinal flies is another name for them and they would form these large clouds around the sewage treatment plant and the neighbors would complain and the treatment plant workers would get upset because every time they'd open their mouth to say something a fly would go in and i can actually tell you from personal experience that they don't
• 01:30 - 02:00 taste very good they're pretty bitter actually so they went to the experiment station the group of scientists at rutgers which is the land-grant college for new jersey and they put together a team to investigate this problem and based on the success they had in controlling that fly problem the state decided to create our department and that was in 1920 that that
• 02:00 - 02:30 occurred so we actually think we're the oldest department in the world if any of you are from north carolina you might like to know that chapel hill in north carolina started at about the same time we think we started one year before them so our department of course has expanded over the years we've looked at many different types of environmental problems you know starting with sewage treatment but quickly spreading to you know water pollution and then over the years adding other things like air pollution
• 02:30 - 03:00 you know solid waste hazardous waste climate change and you know the whole variety of environmental problems one thing that hasn't changed is that right from the beginning our department has used what's referred to as an interdisciplinary interdisciplinary approach to environmental problems so we we combine lots of different scientific disciplines you know chemistry biology microbiology physics mathematics statistics
• 03:00 - 03:30 and we combine these with engineering disciplines as well so we want to investigate these problems and hopefully solve them as well and switch treatment is still one of our interests it's one of the things that i focus a lot of my time on in fact and it's still very important and again hopefully i'll convince you it's it's surprisingly interesting so just a very brief outline i'm going to talk just very briefly about the importance
• 03:30 - 04:00 of sewage and industrial wastewater treatment and then we'll do a little bit on the fundamentals of treatment particularly the biological aspects of treatment and then what i want to focus mostly on is the ecology of these treatment systems because i think that's one of the things that's so interesting about them so first of all the importance so here's a report from unicef uh that's several years old now but they looked at the total deaths in children under the age of five worldwide
• 04:00 - 04:30 in 2012 and found that that year tragically there was still 6.6 million children dying under the age of five this is much better than you know it once was but it's still a pretty tragic number and as you can see um you know a lot of these deaths occur during the first month of life but children who survived the first month are still at risk for a number of diseases pneumonia
• 04:30 - 05:00 is the largest of those and of course others you've heard of like malaria and aids are on the list but notice that just diarrhea is you know the second most important death uh cause of death in children between the ages of one month and five years and uh actually some of the neonatal deaths are from uh diarrhea as well and this is because of poor sanitation because they don't have good sewage treatment their water becomes highly contaminated and then
• 05:00 - 05:30 there's this major cause of death worldwide so we've been fairly successful in controlling this in the u.s and this comes mainly from the 1972 federal water push and control act and the 1977 clean water act amendment which you know her major commitment to controlling water pollution in the u.s and among the many things that this these laws did one of the things is it says that you
• 05:30 - 06:00 cannot discharge anything to a water body in the u.s whether you're a sewage treatment plant or an industrial facility you can't discharge unless you have a permit and then of course in the permit they'll specify how well that wastewater needs to be treated before you can discharge the law also universally applied um a fairly high level of treatment so the original sewage treatment was mostly what was called primary treatment a pretty low
• 06:00 - 06:30 level of treatment but along with those laws the mandate was for this higher level of treatment called secondary treatment and then another thing that the law did was provide a lot of funding federal funding for local communities to build sewage treatment plants and in fact this was recognized at the time and for at least several decades afterwards as the largest public works project in
• 06:30 - 07:00 the history of the world and that's building sewage treatment plants in the u.s so it was a larger investment than the egyptian pyramids or or the interstate highway system and even larger than the investment to put a man on the moon so this was a major commitment again by the people of the united states to to improve uh water treatment uh wastewater treatment to to improve water pollution
• 07:00 - 07:30 in our country and it has been quite successful and the picture on the right is actually the raritan river as it flows near actually flows through the new brunswick campus and when i was a grad student at rutgers i was a ta for course and which we looked at life in the river and only found two species a small freshwater portion tolerant snail and leeches
• 07:30 - 08:00 today we see large numbers of fish and crabs and a variety of other things the water's still not suitable for swimming you can see the sign there beach closed due to contamination uh so there's still quite a bit of work to be done but we should take some pride in the progress we've made it really is a very considerable amount of progress so another reason why wastewater treatment has become very important in recent years is that we now recognize
• 08:00 - 08:30 that we can use treated wastewater to help offset some of our water supply water supplies are becoming quite scarce in many parts of the world and including in many parts of the u.s and some areas in the u.s are now using their treated wastewater as a source of drinking water the treated wastewater goes into the drinking water plant where it's then further treated for to make it drinkable
• 08:30 - 09:00 so the city of san diego for example is doing that because they're so short on water there my son who lives there says the water actually tastes better now than it did when it was uh colorado river water was a larger percentage of their drinking water and then a final thing in more recent years is becoming even of greater interest is that we also realize that some of those contaminants in wastewater actually
• 09:00 - 09:30 are resources that those materials actually could be used the phosphate that's present for example could be recovered and used as fertilizer and there's a variety of other materials present that potentially also can be used and so that's become an interest as well so just a few things about uh wastewater treatments or some general fundamentals about it there's typically a number of different steps in a sewage treatment plant or an
• 09:30 - 10:00 industrial wastewater treatment plant and there's typically preliminary treatment to start off which removes large objects for example then there might be primary treatment still but the requirement now is that we have secondary treatment that's the minimum requirement in the u.s and in some places greater levels of treatment referred to as tertiary and advanced treatment are necessary um and the permit requirements for all sewage treatment plants is that they
• 10:00 - 10:30 must remove at least 85 percent of two classes of pollutants one is the biochemical oxygen demand which is organic matter and then suspended solids as well which is fine particles and these plants use processes that normally would occur you know naturally in a stream but they're able to do them in the treatment plant so that the stream doesn't suffer while it's performing that treatment so virtually all secondary
• 10:30 - 11:00 treatment is biological treatment or really it's microbiological treatment the trickling filter was invented in 1895 it's a bed of rock or nowadays sometimes it's a bed of plastic and wastewater is sprayed over that bed and microorganisms form a biofilm on the rocks on the surfaces of the rock or plastic and as the waste water flows over them
• 11:00 - 11:30 those microorganisms eat the contaminants they utilize those contaminants to meet their growth needs and energy needs slightly later activated sludge process was invented and started to be used and this is a little different it's a suspended growth system the microorganisms grow suspended within the wastewater that's being treated um so there's uh as you can see on the
• 11:30 - 12:00 bottom right there this this is a diffused air uh plant uh so this air is vigorously bubbled uh into the wastewater to keep the microorganisms well mixed and aerated so they have plenty of oxygen as well there's lots of variations there's a number of other treatment methods that have been developed over the years some of which are are in fairly wide use now there's some newer ones that are very promising but what they all share in common is
• 12:00 - 12:30 that they pretty much all are microbiological and they rely on microbes to eat the contaminants or use the contaminants as as their nutrient and energy supply and then after the treatment we need to or as the last stage in the treatment we need to then remove the microorganisms we don't want to be discharging those so we remove the biomass as we refer to it and that's typically not always but it's
• 12:30 - 13:00 typically done by settling or sometimes referred to as secondary settling for secondary treatment and as you can see in on the bottom right the figure there the waste water coming out of secondary treatment looks like stream water in fact in some plants it looks like drinking water it's not at that point yet but it has been greatly cleaned compared to the original wastewater and over 90 of the organic contaminants have been removed
• 13:00 - 13:30 so biological treatment processes were designed by engineers originally by civil engineers and then they be the ones who did waste water treatment were referred to as sanitary engineers and now they're called environmental engineers which is a broader term but they developed these uh processes um we call this empirically they tried things and if they worked then they kept doing them and then they would you know make modifications and
• 13:30 - 14:00 see if that was better than they would make those changes so it's basically by trial and error or by you know by evidence by empirical evidence as to what worked and what didn't work but basically they were considered to be black boxes waste water went in treated wastewater came out and we really didn't know what was going on inside um you know we knew that there was mixing and that there was aeration and so on but we really didn't know how in any in any detail how the
• 14:00 - 14:30 wastewater became treated and of course over time we we've wanted to try to understand that uh for a number of reasons the systems are usually effective even when we knew very little about how they worked they often worked very well for long periods of time but some of them would have problems and some of them would occasionally have problems and of course we want to be able to solve those problems and get back to good treatment levels
• 14:30 - 15:00 and also it's it's likely that if we understand the system better we can get better treatment we can get the same investment of you know all those billions of dollars we can actually get better treatment from that investment and we can also do it ongoing way at a lower cost so for example with lower energy costs which would have both environmental and economic benefits so as we've come to understand these systems what we realize
• 15:00 - 15:30 is that they are in fact microbial ecosystems and these are real ecosystems um in the same way that you you know you you'd see the african savannah and on a you know nature show on tv and learn about that ecosystem these are also ecosystems although they're engineered and they're made of concrete and steel they are still ecosystems and that's my specialty i'm an
• 15:30 - 16:00 environmental scientist whose specialty is microbial ecology in these engineered systems and these systems we use for treatment so that includes sewage and industrial wastewater treatment it also includes composting my phd in fact was on composting which is a treatment system that's that's used for solid organic wastes and we've also worked on bioremediation of contaminated soils and contaminated waters including you know for fairly hazardous waste they can still be treated
• 16:00 - 16:30 biologically and we've even done some projects looking at air pollution control using microbial ecosystems a process called biofiltration to do that so one thing about all ecosystems they require energy if ecosystems don't have inputs of energy they just gradually fall apart so what's the energy available in this ecosystem and of course sunlight is ultimately the
• 16:30 - 17:00 the source of energy for most ecosystems but but these systems even though they're outdoors there's really very little sunlight entering what's you know that that's not really their source of energy so let's think for a minute what is the major component of sewage and actually it's water sewage is 99.9 percent water you know so next time somebody tells you something they're selling is 99 pure
• 17:00 - 17:30 you can tell them well sewage is actually 10 times purer than that the the problem with sewage is that it you know although it only contains 0.1 percent contaminants those contaminants have a big effect if they get into a stream so one of the things that we're very interested in with sewage is the biochemical oxygen demand or bod which you've probably already studied at
• 17:30 - 18:00 this point in the semester but this is a measure of how much organic matter is present it measures the organic matter present based on how much oxygen it would use up if it got into a stream or at least using this test that tries to mimic that and uh since stream water can only hold nine or ten milligrams per liter of oxygen you know if we put in 200 milligrams per liter of bod which is what typical sewage
• 18:00 - 18:30 would have that of course can easily deplete all of the oxygen in the stream even if it's diluted you know 20-fold so that's why we think of sewage as being so highly contaminated and 200 milligrams per liter of bod is also 200 parts per million um and so we can ask the question what percent of sewage is bod and we don't normally think of it this
• 18:30 - 19:00 way because the percent levels of body would be very high uh levels of of contamination much higher than sewage but if we convert it to percent this is only 0.02 percent energy source so if we want to grow microorganisms in the laboratory we might use a very weak medium such as nutrient agar but that would be 40 times stronger that would be 0.8 percent vod
• 19:00 - 19:30 and most bacterial growth meters are are 10 times higher than that in terms of their at least 5 to 10 times higher than that so sewage it turns out is actually a very weak medium for growing bacteria it does have good levels of nitrogen and phosphorus and so on so that's nice but in terms of the basic energy source it's actually very dilute and so in this ecosystem there are all the normal sorts of interactions that you
• 19:30 - 20:00 think of in ecosystems there are predators and there's you know parasites there's mutualism but the main interaction is competition there's actually not enough food supply present and so the organisms there have to compete for it there's relatively little energy available so most of the organisms in sewage treatment actually end up starving to death when we look at the biomass in an
• 20:00 - 20:30 activated sludge system for example we estimate that only one to ten percent of it is actually still alive that some of it might have come into the plant dead but a large proportion of it has died in the plant because it was unable to compete effectively so the organisms that are able to compete effectively you know they win this competition and they increase their proportion in the biomass you know they be become the more predominant species that
• 20:30 - 21:00 are present the losers on the other hand are the ones that can't compete they can't grow as fast and produce as many offspring as as the winners and so they decrease in proportion and may be eliminated entirely and that outcome you know who are the winners and who are the losers that's determined by the environment they're in and and that's based on the treatment plan conditions now a lot of the conditions environmental conditions in a sewage
• 21:00 - 21:30 treatment plant are not controlled by the operators of the plant temperature for example it's too expensive to raise or lower the temperature of water you know for normal sewage treatment and so you know whatever the temperature is that's what the organisms are exposed to and that of course affects who wins and who loses another thing that affects them is the contact time so they spend a certain number of hours in the tank where they're able to feed and these
• 21:30 - 22:00 sewage treatment plant operators can't control that it's based on how fast the water comes into the plant the wastewater comes into the plant so when they originally designed the plant the engineers designed a specific contact time but once the plant starts operating that's really not controlled anymore and then what wastewater you know what's in the wastewater coming in what organic compounds are present and particularly it varies from treatment plant to treatment plant based
• 22:00 - 22:30 on what industries might be in that town and the treatment plant has relatively little control over what you know what comes into the plant they pretty much have to treat anything that gets dumped into the sewer now some plants are able to control ph um so that's one thing that they sometimes can control ph usually stays around neutral but in some plants it will become acidic with time and plants can then control that some plants can control the dissolved oxygen so they are
• 22:30 - 23:00 aerating in many cases the the wastewater and they may have some control over how much air they provide some plants do not some plants basically the air is on or off and that's the only control they have but newer plants they often try to build in control industrial wastewater might not have enough nitrogen or phosphorus in it and treatment plans will then add those nutrients but the one thing that most plants can control
• 23:00 - 23:30 and the way they actually control how successful their operation is is by controlling what we call sludge age which is actually the inverse of the growth rate so let me just explain this a little more so if we look at a typical activated sludge flow schematic we see that the waste water comes in the influence comes into an aeration tank and then the typical plant that'll spend about six hours there it then goes to a settling
• 23:30 - 24:00 tank where the sludge just settled out and the clear wastewater now can go on to further treatment the sludge that settles out gets returned back to the aeration tank because that's the biomass those are the microorganisms that are actually doing the treatment so it takes a little while for this to build up over time but after the first few weeks of operation we now have a working activated sludge plan with the sludge getting returned and performing
• 24:00 - 24:30 the treatment so the waste water spends about six hours in the aeration tank but the biomass gets recycled and then spends another six hours and then it gets recycled again and spends another six hours so it can be much older the sludge age can be much longer than the age of the water in the plant which would only be you know six hours now because it keeps growing because the biomass keeps growing we do have to waste some of it or remove some
• 24:30 - 25:00 of it that's called waste sludge but what it really means is we're removing a portion of biomass and the way most plants are operated the sludge age the amount of time that the sludge spends in the system is often three days or it's often can be longer than that even so while the water's only spending six hours the microorganisms are spending three days or longer but still at that
• 25:00 - 25:30 point that means that we get you know 100 generations a year so the microorganisms completely replace the biomass if there's uh you know 10 tons of biomass in there today uh three days from now there'll still be 10 tons of biomass in there but we also would have removed 10 tons of biomass in that period of time so it's replaced itself every three days so we get more than 100 generations and one interesting thing is that that actually provides then you know within a
• 25:30 - 26:00 few years that's plenty of time for evolution to have occurred in these systems and so in some ways they're like islands right that each individual activated sludge plant or other biological wastewater treatment plant is sort of like an island it's somewhat isolated from other plants and so evolution can occur in that system and we can get somewhat unique organisms there yes organisms that differ somewhat from those in other treatment plants
• 26:00 - 26:30 so let's look at the organisms just for a minute so the most important organisms present are the bacteria and there's lots of different species present we actually don't know most of the the species that are present uh they're not very interesting to look at so you know at 100 power on the microscope they would look something like this basically tiny dots this is actually organism that we isolated from activated sludge and grew in a pure culture in the laboratory so this is a single species
• 26:30 - 27:00 unlike what it would be an activated sludge where to be mixed species present but if we look at them under high power they're still all you know often not that interesting they're just basically bigger dots um but they also can form associations and typically inactivated sludge and um triclin filters as well um they typically form associations in activated sludge they form what we call flock so this is a big you know mass of of
• 27:00 - 27:30 microorganisms most of them dead but there are still a bunch of live ones in here and there's also some just particles that came in with the sewage that are probably stuck in here as well um so those are referred to as flock and they can be fairly small or they can be you know quite large it can be certainly visible to the eye the larger ones can be a millimeter in size although most of them are smaller than that
• 27:30 - 28:00 um and then we also get another type of association which is called a filament so these are bacteria or occasionally fungi but typically bacteria that have their cells arranged end to end to form a single cell wide filament that can be quite long they actually can be become long enough that they become visible to the eye as well there's also all different types of protozoa present so the simplest
• 28:00 - 28:30 protozoa are usually considered to be the flagellates and so one common one the genus name happens to be boto but here's a common one this is a very small you know microorganism uh you know one of the smallest eukaryotes maybe five to ten micrometers in diameter you can see this particular one boto has two flagella there's one there and here's another here there's a variety of different amoeba present i don't know what this one is i can't identify these
• 28:30 - 29:00 these types but this one i do know so this is a genus called arcella and the people who work in treatment plants often use microscopes to follow what's happening in their plants and they refer to these as donuts because that's what it looks like we're looking at this one from the bottom actually and it has a shell they're called testate amoeba which test means a shelled amoeba
• 29:00 - 29:30 and this is the hole in the bottom of the shell that the amoeba can come out of and so it you know crawls around on you know or floats around in the system with a shell on its back as protection this one you can see from the side you can see it's really dome shaped there are also a large variety of the more advanced protozoa which are known as ciliates they so they have uh you know little hairs all over that all over the cell
• 29:30 - 30:00 and sometimes formed into uh siri they're called when they're silly or fused together form spike like objects and here this one uh this is aspa disco which is very common eupotes is less common but i have a better picture of that and you can see the cilia on the front here forming a fringe they also fuse together into a membrane to push food particles down to the mouth which is right down here and then this one also has these spikes or spines that
• 30:00 - 30:30 are made of fused cilia and i've seen them walking around on these or we're using them like oars to swim or jumping like fleas even to push off a surface and probably it also is sort of like a porcupine that these these spikes can act to protect it maybe from a larger predator there's also a number of different types of stalked ciliates so the most common type is a
• 30:30 - 31:00 genus called borticella which has lots of different species and you can see that you know this is a individual vorticella so it's a it's a ciliate that has a stalk that attaches it to a to a surface in this case to a flock and it can close the mouth or when it's feeding it'll open the mouth and since it's it's attached to a surface it can't swim around but what it does do is beat the cilia in a pattern that creates sort of a whirlpool and so
• 31:00 - 31:30 a bacteria might be floating by and get caught in the whirlpool and then sucked into the into the mouth of the protozoa and of course it can close the mouth when it wishes and then vorticella is one of the genera of these types of ciliates that has a myoney so this dark line down the middle of the stalk and you can see in the bottom two pictures here that here's uh here's an individual vorticella and
• 31:30 - 32:00 then uh you know seconds later it's contracted the myanime to pull the head back uh you know to the flock so presumably that's a defense mechanism now myanimes actually comes from a greek word meaning muscle and that's the way it uses them presumably as a defense mechanism then there's also a several other degenerate of stock ciliates um all the others are colonial so there's a you know
• 32:00 - 32:30 branch stalks with all you know these different individuals as part of this colony epistles does not have a mining so it can't contract carcesium on the other hand even though it's colonial it does have a myonine so there so it can contract and then uh one last group of ciliates i want to mention are referred to as suctorians and this particular genus
• 32:30 - 33:00 has little so it actually doesn't have cilia as an adult as a juvenile it does but as an adult it forms a stalk and attaches and then grows instead of cilia it grows these tentacles they look like they have a little flat disc on the end of them and so what will happen is one of the free swimming ciliates like aspardisco will swim by and if it bumps into one of these tentacles this will use that little suction cup to hook onto it and hold it there's actually another species that has spikes instead that'll stab
• 33:00 - 33:30 stab the ciliate and to hold it and then in sort of slow motion it it'll put other tentacles over and and hook those on as well and once it has the its prey you know firmly held in place it then sucks the juice out of it and then releases the the you know the dried out dead cilia and i think by luck i actually caught a carcass over here
• 33:30 - 34:00 there also are small animals that are present and these small animals are referred to in general is metazoa but there's lots of different groups present there are rotifers for example which are interesting to watch they have two toes they have an intestinal tract the mouth is up here they'll plant the foot down extend the head up and then pull the foot after it so they'll move along like an inch worm or a leech or they'll plant the toe down and then
• 34:00 - 34:30 open the mouth up and it has two wheels of cilia in the mouth and it'll use those to create water currents to suck food particles to hit while it's hold you know holding itself in place with its toes or it'll then let go with the toes and can swim using those cilia and swim around and look for food there's also small round worms so they're called nematodes there's a general name for these again just small animals will swim around looking for things to eat
• 34:30 - 35:00 um they're you know aquatic uh small animals there's more advanced worms um so you know anilid worms or relatives of the earthworm for example you can see the different segments here with bristles in between them and this alisoma is this particular genus and then uh another small animal that you've probably heard of you may not have heard of these others but most you probably have heard of tardigrades or water bears they've become pretty popular as organisms that can survive for
• 35:00 - 35:30 relatively long periods desiccated and then you know even after 100 years if they're put back into water then come back to life so you can see again intestinal tract the brain here that has eight legs you know four on each side and if you look at the front right foot here you can actually see some cause there and so those claws would use in its normal habitat to you know hold on to the rocks in the bottom of the stream as it crawled around looking for food for example
• 35:30 - 36:00 it does not use them for for rending elk and that's not where the name water bear comes from it comes from the cause but they're used just to hold on basically and then here's a fungus and we do occasionally see fungi in these systems this particular one is called arthro boat trees and it's you know here's the fungal filament this is not very common but we have seen it a few times and and it forms these special
• 36:00 - 36:30 appendages it looks like sort of like a lasso you might see in a western movie and this fungus tricks nematode worms those small round worms uh into sticking their necks into this noose uh and actually it's pretty sophisticated it actually releases sexual pheromones to attract the nematodes to convince them to stick their head into this noose and then once they're there it pulls the news tight and strangles them and that'll send the filament down to
• 36:30 - 37:00 grow inside them and digest them from the inside out so this is sort of like a venus fly trap of the microbial world so why is this idea of mic looking at these systems uh through the lens of microbial ecology why is that important so as you said before there's severe competition in these systems and survival of the fittest the conditions that are present determine who wins and who
• 37:00 - 37:30 loses but the winners actually determine how good the treatment process is so it determines how good the f1 quality is how clear and how low the bod is in treatment plant f1 and so it's determining the treatment effectiveness and we've also learned over the years that we can use these organisms as indicators we can look for slow or rapid changes in the system to see what's happening and you know once we
• 37:30 - 38:00 get to know the the players we get to know when we see this particular type of organ and we see rota first for example that that means the sludge asia is longer and that this system looks healthy if they disappear that tells us that something is going on and we better check into it so if we're going to recognize the organisms we can we can actually tell what conditions are occurring in the treatment plan you know based on our experience now
• 38:00 - 38:30 so let me just briefly talk about two problems that occur in activated sludge plans two fairly common problems and how we can sometimes diagnose those um so uh the most severe problem that occurs is referred to as bulking so imagine that we put our some of the sludge from a system from the aeration tank we just you know collected a sample that and put it in a graduate cylinder and watched it over time so initially it would look uniform but over time
• 38:30 - 39:00 the sludge would settle to the bottom and we'd have clear water above that and we expect within 30 minutes that the volume would settle down typically to around 20 percent of the original volume if we have bulking in the plant though what will happen is that the sludge won't settle well so you know imagine that this was the settling tank we'd have sewage sludge all the way up to near the top of the settling tank if this happened and that's the problem that we call
• 39:00 - 39:30 bulking and if we look under the microscope what we find is that there will be excessive growth of filaments when we have bulking and so it actually just physically interferes with settling you know this flock can't settle very tightly down or very compactly down at the bottom of the settling tank because there's all these filaments sticking out and here some of the filaments bridge from one flock to the next keeping them apart you know preventing them from closely approaching each other in the bottom of the tank
• 39:30 - 40:00 another problem that occurs is what's referred to as foaming and you can see on the top of the settling tank this thick foam is accumulated and some of it's actually gone over the baffle and is then going out over the weirs and into the effluent and uh you know causing uh this material to go out into the stream and if we go back under the microscope when we have this problem what we'll often see is this branched
• 40:00 - 40:30 network of filaments and these are caused by bacteria in a group that includes nocardia so we refer to these as nocardial-like bacteria and they're responsible usually for this type of foaming problem and so based on the different filaments that we observe we actually can sometimes figure out what's causing the bulking or foaming problem we originally thought that there was
• 40:30 - 41:00 only one type of filament when i was a graduate student in the 70s we thought that serato's natins was the cause of bulking but what we've learned since then is that there's actually lots of different filaments and each one of these filaments if it's present in excessive amounts that means that it won the competition and so whatever conditions allowed it to win the competition those conditions are what caused the bulking in that plant so here for example is type 1701 we
• 41:00 - 41:30 don't even really know the name of this bacterial filament but we know that it does occur sometimes in excessive amounts and that leads to bulking that's actually low dissolved oxygen bulking and here's another type which is pretty easily distinguishable it's type double of 41 so we can recognize these different types even if we can't name them and so we've just given them these names now these numbers [Music]
• 41:30 - 42:00 holistic menu back their hidrosis very thin filament that's perfectly straight usually microfix parvicella is this coil type of filament also quite thin here's ferratos natin's the one that we used to think was the only one and that this is uh unusual in that it has this branching and then here's another very unusual one this is veggie toa and the yellow granules you see here are actually
• 42:00 - 42:30 sulfur granules inside the cells so belgian toa can use hydrogen sulfide as an energy source it doesn't need organic matter for energy it can actually use hydrogen sulfide for its energy and it then deposits elemental sulfur inside the cell which is actually another food reserve or energy reserve because if it runs out of hydrogen sulfide it'll switch over and use the sulfur and convert that to sulfate or actually sulfuric acid so that's how it gets its energy
• 42:30 - 43:00 and so based on that we've been a based on identifying these filaments we've been able to determine that there are in fact a variety of different causes of bulking for example low d.o bulking bulkier if there's not enough dissolved oxygen d o stands for dissolved oxygen uh you know the spratus natins and 1701 and some other filaments uh get a selective advantage and and they'll grow in their proportion in the sludge and then cause bulking on the other hand if there's low ph as
• 43:00 - 43:30 another example we'll get fungi and growing if if there's a high sulfide concentration coming in in the sewage we'll get benjito so we're able to diagnose these problems so uh just summarizing again sewage treatment is important uh hopefully you now at least are partially convinced that it also can be interesting and if any of you plan to go on to graduate school and do research and maybe even ecological
• 43:30 - 44:00 research or evolutionary research one advantage of looking at these systems interestingly is that they have such short generation times if you want to study evolution and you use giraffes as the animal you're going to look at it's going to take you a few hundred years to to get your phd on the other hand with these microorganisms since we can get many generations within a couple years it takes a more reasonable amount of time um also it's uh you know there are sewage treatment plants in
• 44:00 - 44:30 pretty much every uh community or at least within every county pretty much uh you know throughout the us um and uh so it's pretty easy to go to a treatment plant you don't have to save up for a few years and then you know book passage to uh to the uh you know tanzania or someplace like that to study the giraffe i'm not sure i would say going to a soot tree plant is as much fun as going to the savannah but that's a different issue and there
• 44:30 - 45:00 are still a lot of challenges though one of the things with sewage treatment plants is that the conditions there are always changing they change from from year to year but also from week to week and even within a day you know from hour to hour also another interesting problem is that or interesting issue is that if we think of a flock of you know bacteria as being spherical as we penetrate into the flock towards the center conditions change quite a bit the
• 45:00 - 45:30 dissolved oxygen is much higher out here than it is at the center of the flock where it might actually be zero and likewise the food the dissolved food in the liquid doesn't penetrate very far into the flock before it all gets used up so that's an interesting uh issue as well and gives interesting results when when that's been studied another thing is we don't actually know most of the organisms so imagine going to africa and seeing all
• 45:30 - 46:00 those amazing animals there and not knowing anything about them not knowing their names or anything else about them so so activated sludge is sort of that way now and there's a lot of opportunity to really make a difference now so with that uh just point out that there are actually a lot of terrific careers in environmental science and that's whether you want to get a phd or a bachelor's degree or you're
• 46:00 - 46:30 you're hoping to finish your education with high school um it is one of the best prospects for employment if you look at the department of labor before the pandemic and hopefully again afterwards if you look for employment prospects you'll see that the environmental field is one of those areas that you might want to look at okay thank you very much