Before diving in, I would like to do a little explanation of why I have chosen to research and post my findings on the topics to come. Consider this post the first, in a sequence of different topics to come. I have found that by looking into these topics, I have come to develop a further understanding of how things take place in our fabricated "marine ecosystems." I want to help by condensing these topics and present them to you. Although, most of these will be generalized in order to keep from creating a lengthy and science-jargon filled thread. I invite discussion and respective challenges! It will only benefit us all. You may have previously seen one of my more recent posts, which relates to the Nitrogen Cycle. It was my first post, and I am hoping that the ones to come will be much more organized. The introduction in that one is very similar to this one. I wish to present information to the reader, so that they may use it in any fashion that they wish. You will come to find that many of these topics will end up relating to each other. Please, feel free to use them how you wish. However, to avoid confusion, I must ask that we limit discussions and questions to each topic's particular thread. With that being said, let us begin.
The topics of choice today are: Biochemical Oxygen Demand (BOD) and Wastewater Treatment. The understanding of the first topic, will help hobbyist to identify problems and solutions for a variety of problems. The latter topic is designed to assist those who wonder where their water comes from and how it is treated. Like many systems in nature, the objective is to obtain balance. We experience what we call problems, only when balance is interrupted such as the dying off of fish in aquariums. However, nature views this as a solution, because it is trying to achieve balance. I choose to include these topics together, because you must understand one in order to begin understanding the second. Like previously mentioned, Biochemical Oxygen Demand can be used to understand other topics as well.
The major key point to take away from BOD is that it is a measurement of variables that work together to achieve balance between the levels of oxygen and the levels of reduced organic material. Basically, we understand that there are microbes that use carbon (organic material) to support their functions. Once this product is utilized, it is then deposited back to the environment as oxygen, which is used by animals to survive and support their functions.
The problem is that a lot of these microbes are aerobic, which means they are dependent on oxygen in order to initiate these processes. When we notice an eccentric introduction of reduced organic material of significantly large quantities, we also notice a large spike in aerobic processes conducted by microbes. In turn, these microbes out-compete the surrounding living organisms for oxygen. Which can cause our fish and other oxygen-dependent organism to die. We can also see this occurrence with unwanted nuisance algae in our tanks. They utilize nutrients to promote growth, thus also out-competing our livestock.
How these organic and inorganic materials enter our aquariums is via the Hydrologic Cycle. In the natural world, this would be seen as precipitation. Water vapor is involved as well, which is how it would happen in our homes. In general, microbes and wastes (organic or inorganic) attach to these water molecules at the surface where they diffuse into the water column via fixation by processes that are involved such as the Nitrogen or Carbon Cycle. They leave by evaporation, where water vapor enters back into the atmosphere. Thus, how carbon dioxide and nitrogen gas return to the air.
BOD is measured by a complex machine and methods, so the common hobbyist must think in terms of relativity and balance. Like mentioned in my previous thread regarding the Nitrogen Cycle, there is no way to determine the exact species and what processes they are using in our aquariums without the help of professionals, or professional-grade equipment. This in turn creates a problem for analyzing what our BOD threshold would be, considering that the species involved also have to be known.
To clarify further, the higher the concentration of organic substances, the higher the BOD arises from microbial oxygen consumption. In other words, the rate of decrease of dissolved oxygen which is measured by the BOD analyzer (tool used by experts on a larger scale) is roughly proportional to the amount of dissolved organic matter available for respiration.
My advice, is to stay routine in how you preform maintenance. Consistency is a part of balance, in my opinion. Take out roughly as much water as you put in, while doing water changes. Also, keep feed times and the amount as routine as possible. Think balance, because the ocean can counter chemical swings appropriately because it is an open-loop system. Whereas, our aquariums are closed-loop systems. When there is a need to change something, work in increments. This in turn allows the entire system to adjust at a rate that is more secure.
I would like to provide a real life example of how BOD works via the Deepwater Horizon incident:
Many of the pollutants that contaminated the surrounding water due to the unfortunate incident of the Deepwater Horizon, were metabolized to carbon dioxide (CO2). This was achievable by oil-eating bacteria that feed naturally on oil that leaches slowly from the Gulf's sediment. But with the sudden large input of oil, it caused a sudden rise in microbial respiration and BOD levels throughout the Gulf, which in turn lowered the amount of dissolved-oxygen available that the wildlife in the ocean needed in order to survive. So, in reality the oil itself did not kill as much marine life as did the microbes who consumed the oil did.
An even more simpler explanation:
You are in a very tiny room. A type of room that when you breathe, it almost feels as if the air is "thick." Now, add ten more people. You all need oxygen, but you are competing for that oxygen. Of course, you are feeling what the animals that suffered through the Deepwater Horizon felt. There are also many variables that this simple scenario does not take into account, but it does well enough to represent what happens through these processes relating to BOD.
Now that the reader has grasped a better explanation of Biochemical Oxygen Demand (BOD), the discussion of Wastewater Treatment can begin.
The purpose of Wastewater Treatment is defined by my textbook ("Microbiology: An Evolving Science. 4th Edition," by Slonczewski and Foster) as: "To decrease the BOD and the level of human pathogens before water is returned to local rivers." I found this topic interesting because many hobbyist seem to be curious as to where the water they use comes from and what they should do in order to promote the best water quality.
Upon reading I found that the process happens in many steps:
It really does not take much to generalize the sequence of events for most water treatment facilities. However, I am sure some are different than others. There are also wet lands (Natural and artificial) such as the Everglades, that are use to purify water. It really depends on your local area, on how you get water.
Personally, I use a 4-Stage RO/DI unit to help reduce the number of trace elements that may be present in my water. I feel much more relieved that way, because there are not as many trace elements left for nuisance algae to take advantage of. It also comes with it's own TDS (Total Dissolved Solids) meter to track the quantity of what I consider "impurities," that may be present in my tap water. However, I am not sure if a 4-stage is adequate enough. Maybe some of you can chime in and help me to determine if that is so!
I give credit to the authors Slonczewski and Foster. I do not aim to regurgitate the information that this books provides to the reader. I do aim to take my current knowledge, along with the knowledge provided by this book over multiple chapters, condense them together and then provide it all to the reader to do as they wish. I do not know it all, and I do not claim to do so. I am here to help and learn, and I hope by posting this thread along with the others to come, that I can do just that. Please, comment and let me know if this article was helpful or useful to you. Or start a discussion. If you have any constructive feedback, send me a personal message because I would love to hear how I may improve. Thank you to all of those who gave it the time to read, and also to those who choose to participate in discussion!
The topics of choice today are: Biochemical Oxygen Demand (BOD) and Wastewater Treatment. The understanding of the first topic, will help hobbyist to identify problems and solutions for a variety of problems. The latter topic is designed to assist those who wonder where their water comes from and how it is treated. Like many systems in nature, the objective is to obtain balance. We experience what we call problems, only when balance is interrupted such as the dying off of fish in aquariums. However, nature views this as a solution, because it is trying to achieve balance. I choose to include these topics together, because you must understand one in order to begin understanding the second. Like previously mentioned, Biochemical Oxygen Demand can be used to understand other topics as well.
The major key point to take away from BOD is that it is a measurement of variables that work together to achieve balance between the levels of oxygen and the levels of reduced organic material. Basically, we understand that there are microbes that use carbon (organic material) to support their functions. Once this product is utilized, it is then deposited back to the environment as oxygen, which is used by animals to survive and support their functions.
The problem is that a lot of these microbes are aerobic, which means they are dependent on oxygen in order to initiate these processes. When we notice an eccentric introduction of reduced organic material of significantly large quantities, we also notice a large spike in aerobic processes conducted by microbes. In turn, these microbes out-compete the surrounding living organisms for oxygen. Which can cause our fish and other oxygen-dependent organism to die. We can also see this occurrence with unwanted nuisance algae in our tanks. They utilize nutrients to promote growth, thus also out-competing our livestock.
How these organic and inorganic materials enter our aquariums is via the Hydrologic Cycle. In the natural world, this would be seen as precipitation. Water vapor is involved as well, which is how it would happen in our homes. In general, microbes and wastes (organic or inorganic) attach to these water molecules at the surface where they diffuse into the water column via fixation by processes that are involved such as the Nitrogen or Carbon Cycle. They leave by evaporation, where water vapor enters back into the atmosphere. Thus, how carbon dioxide and nitrogen gas return to the air.
BOD is measured by a complex machine and methods, so the common hobbyist must think in terms of relativity and balance. Like mentioned in my previous thread regarding the Nitrogen Cycle, there is no way to determine the exact species and what processes they are using in our aquariums without the help of professionals, or professional-grade equipment. This in turn creates a problem for analyzing what our BOD threshold would be, considering that the species involved also have to be known.
To clarify further, the higher the concentration of organic substances, the higher the BOD arises from microbial oxygen consumption. In other words, the rate of decrease of dissolved oxygen which is measured by the BOD analyzer (tool used by experts on a larger scale) is roughly proportional to the amount of dissolved organic matter available for respiration.
My advice, is to stay routine in how you preform maintenance. Consistency is a part of balance, in my opinion. Take out roughly as much water as you put in, while doing water changes. Also, keep feed times and the amount as routine as possible. Think balance, because the ocean can counter chemical swings appropriately because it is an open-loop system. Whereas, our aquariums are closed-loop systems. When there is a need to change something, work in increments. This in turn allows the entire system to adjust at a rate that is more secure.
I would like to provide a real life example of how BOD works via the Deepwater Horizon incident:
Many of the pollutants that contaminated the surrounding water due to the unfortunate incident of the Deepwater Horizon, were metabolized to carbon dioxide (CO2). This was achievable by oil-eating bacteria that feed naturally on oil that leaches slowly from the Gulf's sediment. But with the sudden large input of oil, it caused a sudden rise in microbial respiration and BOD levels throughout the Gulf, which in turn lowered the amount of dissolved-oxygen available that the wildlife in the ocean needed in order to survive. So, in reality the oil itself did not kill as much marine life as did the microbes who consumed the oil did.
An even more simpler explanation:
You are in a very tiny room. A type of room that when you breathe, it almost feels as if the air is "thick." Now, add ten more people. You all need oxygen, but you are competing for that oxygen. Of course, you are feeling what the animals that suffered through the Deepwater Horizon felt. There are also many variables that this simple scenario does not take into account, but it does well enough to represent what happens through these processes relating to BOD.
Now that the reader has grasped a better explanation of Biochemical Oxygen Demand (BOD), the discussion of Wastewater Treatment can begin.
The purpose of Wastewater Treatment is defined by my textbook ("Microbiology: An Evolving Science. 4th Edition," by Slonczewski and Foster) as: "To decrease the BOD and the level of human pathogens before water is returned to local rivers." I found this topic interesting because many hobbyist seem to be curious as to where the water they use comes from and what they should do in order to promote the best water quality.
Upon reading I found that the process happens in many steps:
- Preliminary Treatment (Screens that remove solid debris such as sticks, dead animals, and feminine hygiene products.)
- Primary Treatment (Fine screens and sedimentation tanks remove insoluble particles. Particles are then recombined with the solid products of wastewater treatment to form sludge. Sludge ultimately is used for fertilizer or landfills.)
- Secondary Treatment (Microbial ecosystems that decompose the soluble organic content of wastewater, by aerobic and anaerobic respiration. Nutrient removal process may include biological removal of nitrogen and phosphorus. If included at this point, nitrogen is removed by nitrifying bacteria that oxidize ammonium, and phosphorus is removed by polyphosphate-accumulating bacteria. The microbes form particulate flocs of biofilm. The flocs are sedimented as sludge, also known as activated sludge.)
- Tertiary (advanced) Treatement (Filtration of particulates from the microbial flocs of secondary treatment, may include chemical processes to decrease nitrogen and phosphorus. The final step involves disinfection to eliminate pathogens, usually by a chemical process such as chlorination. Then treated water is returned to local freshwater sources.)
It really does not take much to generalize the sequence of events for most water treatment facilities. However, I am sure some are different than others. There are also wet lands (Natural and artificial) such as the Everglades, that are use to purify water. It really depends on your local area, on how you get water.
Personally, I use a 4-Stage RO/DI unit to help reduce the number of trace elements that may be present in my water. I feel much more relieved that way, because there are not as many trace elements left for nuisance algae to take advantage of. It also comes with it's own TDS (Total Dissolved Solids) meter to track the quantity of what I consider "impurities," that may be present in my tap water. However, I am not sure if a 4-stage is adequate enough. Maybe some of you can chime in and help me to determine if that is so!
I give credit to the authors Slonczewski and Foster. I do not aim to regurgitate the information that this books provides to the reader. I do aim to take my current knowledge, along with the knowledge provided by this book over multiple chapters, condense them together and then provide it all to the reader to do as they wish. I do not know it all, and I do not claim to do so. I am here to help and learn, and I hope by posting this thread along with the others to come, that I can do just that. Please, comment and let me know if this article was helpful or useful to you. Or start a discussion. If you have any constructive feedback, send me a personal message because I would love to hear how I may improve. Thank you to all of those who gave it the time to read, and also to those who choose to participate in discussion!
Last edited:
