# Biotechnology in Wastewater Treatment

2686 words (11 pages) Essay in Environmental Sciences

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Topic #19: Biotechnology in Wastewater Treatment

Group #13

Overview

Recovery of industrial and sewage water has been one of the major environmental concerns humanity encountered. Clearly, with the amount of daily water consumption rising as rises world population and its needs, new and effective ways must be applied to recover and, then, reuse water. At this moment, biological ways to treat wastewater are widely applied due to their numerous benefits and flexibility (as will be described below).

While the removal of organic contaminants is fixable issue, industrial wastewaters often contain extremely high amounts of ammonia and nitrates which are dangerous for both humans and marine life, and cannot be normally converted to biomass by bacteria. A type of bacteria, anammox bacteria, has been discovered less than 30 years ago with its outstanding ability to turn harmful nitrogen-containing compound into N2 gas. Both aerobic and anerobic bacteria have been adapted in biological water recovery systems. TO BE CONTINUED

Subtopics:

Biological Nitrification of Wastewater

A process by which the elimination of ammonia through wastewater treatment or sewage treatment is being done by microorganisms. The method is prepared to turn all ammonia in wastewater into nitrate due to the bad affect that the presence of ammonia has on aqueous creatures 1. In excess of ammonia in water fish might suffer a loss of equilibrium, hyperexcitability, increased respiratory activity and oxygen uptake, increased hart rate ,and could lead to death2 .

Currently, the conventional biological nitrification process is carrying out by the metabolism of two kinds of autotrophic aerobic bacteria in two steps which occurring respectively. Firstly, nitrosomonas oxidize ammonia to nitrite, and secondly, nitrobacter oxidize nitrite to nitrate. Those bacteria require a specific surrounding environment of pH, temperature and alkanility. Also more air than is required to treat for biochemical oxygen demand (BOD) that make this process expensive due to the high cost of pumping oxygen inside the system1.

The coming improvement technique , Daniel Noguera and Katherine McMahon professors of civil and environmental engineering at the University of Wisconsin–Madison are studying how the anammox bacteria might improve this process and decrease the cost too3.Anammox bacteria are anaerobic bacteria , were discovered in wastewater sludge in early 1990s, have an exclusive ability to convert or combine ammonium and nitrite or nitrate to form nitrogen gas(maintain the cycle of N2 in nature) through their metabolism. Also this bacteria are responsible for up to 50% of nitrogen losses in the marine environment4. One of the benefit of using anammox bacteria is reducing the cost since they do not require oxygen, according to this research pumping, oxygen to the system is about 50% of the total cost of the wastewater treatment,. Another benefit upon the conventional method is converting the larger amount of ammonium to Nitrogen gas and less amount to nitrate. In addition, there is a disadvantage of inability to perform this job in pure culture (live in community) because they rely on other heterotrophic microorganisms to provide them with necessary elements to grow and metabolise. In conclusion, using anammox bacteria might advance the future of wastewater treatment3 .

Aerobic Biological Wastewater Treatment

What is aerobic biological wastewater treatment and how does it work?

Aerobic biological water treatment is an efficient process of removal organic material and water contaminants (phosphorus, nitrogen) from wastewater with the use of aerobic bacteria and oxygen.

Bacteria break down organic matter (consumed oxygen acts as a electron receptor) and turn it into carbon dioxide and produce sludge (new biomass). Diffused aeration systems or surface aerators are most commonly used to provide oxygen. Total suspended solids (the biomass) are further removed by filtration and carbon dioxide is released into the environment5. Nitrogen and phosphorus are vital nutrients for microbial growth and are consumed by bacteria. Thus, regular nitrogen and phosphorus removal is converting them to biomass by aerobic bacteria. However, in case the concentrations are higher, dissimilative nitrogen (phosphorus) removal can be applied6.

Despite high energy consumption, biological nutrient removal system ensures that the recovered wastewater meets the strictest requirements of Biochemical Oxygen Demand (measures the amount of organics in a sample), and Total suspended solids (measures the amount of undissolved solids in a sample)7. Even though aerobic process produces

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7 times more biomass than anaerobic process8, the advantage of this treatment is that the removed biomass can be used as an odour-free soil fertilizer through a simple operation7. The main benefit of this procedure over the anaerobic treatment is relatively lower process and equipment cost. Additional funds may be required for maintenance and monitoring9. Depending on the type of the reactor used, aerobic treatment can be space consuming (biological discs, stabilization ponds, trickling filters, etc.) or can require smaller areas (sequencing batch reactor). The loading rate of aerobic wastewater recovery is much lower (max of 9000 g Chemical Oxygen Demand (COD) per m3), while the amount of matter that can be processed in anaerobic system goes up to 31 kg COD/m3. There is no complication in terms of oil and grease removal from the system in aerobic process, which is a time-saving factor comparing to anaerobic treatment8. The aerobic process is capable of removing up to 98% of organic pollutants, however, studies indicate that there are traces of cosmetic, pharmaceutical and industrial products, as well as detergents. The main negative factor of the process is the carbon dioxide being released into the environment, causing a greenhouse effect. With the increasing use of aerobic water recovery, the last could become an issue of major concern 10.

Waste Water Treatment with Anaerobic Methods

Anaerobic and aerobic methods are both used in waste water treatment, both utilizing microbes to remove toxins and other compounds from aqueous waste. In both methods, there are advantages and disadvantages that come into play, depending on the waste being treated and the route a facility or company wishes to take11.

A system using methanogenic archaea, or other anaerobic microbes, is one that does not require oxygen to treat waste water. Notable struggles paired with obvious benefits of anaerobic treatment provides a question of whether or not the method will be successful in treatment of the waste water, depending on a number of factors12.

With anaerobic waste water treatment, an important advantage is the capacity for large loads. In some cases, it is actually necessary to have a higher volume of water being treated at one time13. In aerobic conditions, there must be a lower volume to better control parameters. Methanogenic archaea are used to treat waste water in anaerobic conditions and produce methane as a byproduct12. The production of methane can serve as an energy source for use in the process or harvested for use outside the process. In terms of biological waste, a low yield of solids means less waste in general, allowing the anaerobic process to carry out with more efficiency than its aerobic counter method (Purely in terms of waste production, not considering yield of energy). Low waste yield means less cell yield, and this indicates that little to no nitrogenous or phosphoric macronutrients need be added to fuel the cell respiration process 13,11.

The inhibiting factors surrounding anaerobic waste water treatment seem to outweigh the positives. Methanogenic microbes grow slowly13 and the gaseous waste produced by them may be filled with volatile organic acids that need be further processed (if the water being treated has a high sulfur content or the microbes are not healthy) 13. The anaerobic process is not favoured in situations where the waste being treated is high in fats or oils, because the process is not energy efficient and the enzymes requires to break down these molecules may not be present11. Along with these disadvantages, methane producing microbes may require other macronutrients to flourish, and these may not be readily available13.

Job Market of wastewater treatment

How Wastewater Treatment started and progressed overtime?

Wastewater treatment has just become a more common practice then before and very important. Meaning that wastewater treatments weren’t all that common until the [19th century, when big cities]14, started to understand how wastewater treatments can help with reducing pollution in the water that was being used and discharging into the environment15. Canadian municipals are continuously trying to upgrade their level of wastewater treatment since 1983. It has improved from [40% in 1983 to now 69% in 2009, then now only leaving 18% of primary wastewater treatments and even less sometimes, plus more and more Canadians are using household septic system to their sewages therefore, that becomes another 13%.]16. Based on these statistics’ wastewater treatments has progressed and is still progressing in Canada. Although what will be addressed is the pros and cons of the wastewater treatment based on costs and the job itself. Working there are many advantages and disadvantages of working in the waste water treatment industry. Furthermore, what industries are doing to make it more wastewater treatments more cost effective and easier to work in. Wastewater treatment has become very important and how the industries are making better by cost, process, environment is good to understand to know how we could make it better overtime.

Many of the wastewater treatments use bacteria or other types of microorganisms to help with the process of cleaning the sewages. Therefore, this mechanism has increased the waste water treatments. The advantages of working in wastewater treatments is that its cost effective, ‘’process of building /installing sewage system’’17 is not all that cheap although the operation of it, is cheap. Since sewage systems have no pumping stations and are simply reply on gravity, the results are way cleaner and minimizing financial obligations. Although, obviously more advanced sewage systems cost more and depending on the conveniences of the community, may cost more but is worth the money. Nitrification without chemical usage which is process done by ‘’oxidation to release nitrate’’18, because wastewater processes and mechanics goes through harmful chemical/biological substances and cast it aside, that makes the water safe before it reaches the environment and causing no more damage to the community and less to the environment. It is also easily maintained mechanical work and self-sustaining system. ‘’The self-sustaining system of gravity sewage is able to self-clean therefore, keeping the sewage pipes clean and also keeps the operation going’’17. Disadvantages is that it’s a hassle in the up keeping of the sewage system because it is complex and does require a lot of practices of it and taking precaution to do it the right way. Another thing that is difficult and important is the temperature, because it affects the tanks condition depending on what it is. Shifting of temperature controlled or not does affect the performance of the system and lifespan of the components. Also, plants do need ‘’at least 3 tanks for storage of waste or to process the waste’’17, that is extra cost and time for the sewage wastewater treatment of plants. Wastewater treatment still a huge part of pollution, seems that slowly we are trying to minimize and hopefully overtime it will get better.

Future projects

Geobacter and Shewanella are gram negative bacteria. They have a special trait that could be used in the decontamination of water sources. The two bacteria do not make ATP like a large percentage do, but by removing electrons for metals. When the metallic atom is robbed of its electron it becomes less soluble in water. Using that to treat the water near the Hamilton with addition water treatment. That is just something that can be done close to home. Using these microbes in reclaimed mine restoration. Adding these bacteria to each layer that is put back into the mine be saturated to insure maximum neutralizing19.

Geobater has shown that it will take electrons from uranium. If this organism can eat uranium and its daughter atoms all of the waste, we have in storage could be used again and again. The used rods could bed used as the catalysed in a bacterium run battery. Maybe used a large amount of geobacter in damaged reactors. Breaking down the uranium will make for a safer environment. A good amount of radiation has leaked into the pacific because of the Fukushima power plants containment failures19.

References

1. Nye, J. (2010). Addressing the challenge of removing ammonia from wastewater. Retrieved form https://www.waterworld.com/articles/print/volume-26/issue-3/editorial-features/addressing-the-challenge.html
2. Brian, O. (n.d.). Ammonia in groundwater, runoff, surface water, lakes and streams. Retrieved Feb 3, 2019, from https://www.water-research.net/index.php/ammonia-in-groundwater-runoff-and-streams
3. Schmidt, S. (2017). Bacteria may supercharge the future of wastewater treatment. Retrieved from https://www.water-research.net/index.php/ammonia-in-groundwater-runoff-and-streams
4. Kuenen, J. (2008). Anammox bacteria: From discovery to application. Retrieved from https://www.water-research.net/index.php/ammonia-in-groundwater-runoff-and-streams
5. Aerobic vs. Anaerobic Treatment in Wastewater Systems: Part 1. (2019). Retrieved from https://www.ebsbiowizard.com/aerobic-vs-anaerobic-treatment-in-wastewater-systems-part-1-2-1275/
8. Shete, B. S., & Shinkar, N. P. (2003). Comparative Study of Various Treatments For Dairy Industry Wastewater. Retrieved from https://www.researchgate.net/publication/260631762_Comparative_Study_of_Various_Treatments_For_Dairy_Industry_Wastewater
9. Jana, A., Kundu, D., & Mondal, T. (2017). Aerobic wastewater treatment technologies: A mini review. Retrieved from https://www.researchgate.net/publication/323834605_Aerobic_wastewater_treatment_technologies_A_mini_review
10. Blue, M. (2017). Pros & cons of biological wastewater treatments. Retrieved from https://sciencing.com/pros-cons-biological-wastewater-treatments-24030.html
18. SAMCO. (2016). The importance of wastewater treatments for your facility: is it necessary? Retrieved from https://www.samcotech.com/important-wastewater-treatment-necessary/
19. Geobacter metallireducens GS-15. (n.d.). JGI Genome Portal. Retrieved Feb 8, 2019, from https://genome.jgi.doe.gov/portal/geome/geome.home.html

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