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EmersonRemovalPPCPsbyEcoReactor

Page history last edited by Ian Balcom (Dr B.) 6 years, 6 months ago

Effects of Ecological Wastewater Treatment Systems on Common Pharmaceuticals and Personal Care Products Removal

Aaron Emerson

Shane MacDougall

David Weber

5/10/12

Abstract: With the development of new age pharmaceuticals and widespread distribution, the presence of such chemicals is becoming a notable issue in terms of environmental water quality. As the effects of the bioaccumulation of these products is in many cases unknown, let alone the effect of large doses on people who are not seeking medicinal benefits, the ability for wastewater treatment systems to remove such compounds is a necessity now and in the future. The development of new and dynamics processes has led scientists and ecologists familiar with this process to design living alternatives to traditionally mechanical systems. The ability of these new systems to cope with high quantities of anthropogenic chemicals is an emerging technology known as Ecological Wastewater Treatment, and the study of one such example has begun to produce usable data for development of better systems.

Introduction:

The removal of chemicals from both natural and human-affected waste streams is a known quality of wetland plant species, providing an existing environmental system already designed to pull chemicals from flowing water (Stottmeister, 2003). This service is provided by life forms in exchange for the addition of nutrients (provided by material that is considered a waste product) and sufficient environmental ambience to maintain survival with little more energy needing be added to the system. Currently, large scale mechanically engineered processes are imposed by eliciting the services of masonry, metallurgy, gravity and electricity. Both systems have pros and cons, but a perfect model is yet to be presented for the removal of a chemical class known as Contaminants of Emerging Concern with the subset Pharmaceuticals and Person Care Products (EPA, 2010). The implication of phytoremediation techniques provides an extensive host of possible natural filtering mechanisms whose specific qualities of waste and by-product removal are still largely unknown. The development of a closed loop plant and bacterial system that is effective at removing the nutrients from human waste as well as anthropogenic drugs and chemicals that is also self-regulating has led to a treatment system known as Ecological Wastewater Treatment (Todd, Josephson 1994). The “Living Machine” located on Interstate 89 in Sharon, VT is an example of how this idea can be implicated in a region that is affected by seasonal changes in temperature. Designed within a large greenhouse the system is maintained in a temperature range of 60-80⁰F, the Living Machine has the capacity to handle up to 9000 gallons of wastewater influent generated by the rest room facilities of the heavily trafficked rest area. Using a system of interconnected aerobic and anaerobic tanks to culture bacteria for the digestion of various organic waste products, influent material from the restroom facilities is broken down and filtered from the water. Though the increase of Contaminants of Emerging Concern was not a predicted component of modern waste streams, effectiveness of the diverse biological systems for facilitating the changing levels of both organic and inorganic chemical compounds and they’re ability to remove such material has advantages beyond the energy-intensive mechanized systems that are designed treat human waste water.

The treatment process of the living machine starts with the anaerobic reactor. The anaerobic reactor removes the majority of the incoming biodegradable organic matter (BOD) such as solids and other floatable materials from the water. The breaking down of BOD by the anaerobic reactor is beneficial to the next step in the process which is the Anoxic reactor. (Esi Engineered Solutions. 2005).

The Anoxic reactor is the first aerated reactor that the waste water enters into. The anoxic reactor helps cultivate two main types of microorganisms being Filamentous and floc-forming microorganisms. Typically the system is set up to selectively cultivate floc-forming microorganisms because they have the ability to clump together and settle in the tank and not get washed away. Although Filamentous microorganisms are useful for the breakdown of BOD, Filamentous microorganisms are not typically selectively grown because they are light weight single bacterium cells therefore their colonies get washed away. The environment of the anoxic reactor tank has oxygen present only in compounds such as nitrates and sulfates which promotes the growth of the microorganisms. The environment of the anoxic reactor, which is between anaerobic and fully aerobic in terms of the oxygen content in the wastewater, is maintained by the controlling of the aeration. The wastewater is constantly recycled from the anaerobic reactor to the anoxic reactor which returns nitrate for the conversion to nitrogen gas. The anoxic reactor, as well as the first aerobic reactor, is covered with a bio filter which helps eliminate odors from the wastewater treatment. (Esi Engineered Solutions. 2005)(Shi, W., Wang)

The next tank that the water enters into is the closed aerobic reactor which is the first fully aerobic portion of the living machine. This tanks purpose is to remove the majority of the BOD in the effluent from the anoxic reactor and to eliminate odorous gases from the wastewater. Nitrification or the conversion of organic and ammonia nitrogen to nitrate occurs in this reactor. The closed aerobic reactor is aerated with bubble diffusers to provide oxygen and to keep the contents of the wastewater mixed. (Esi Engineered Solutions. 2005).

The open aerobic reactors follow the closed aerobic reactor and are the next step in the process of the living machine. There are a series of three open aerobic reactors that the water enters into which reduce the BOD levels and complete the nitrification process. The surfaces of the open aerobic reactors are covered with vegetation which provides a surface for the growth of the floc-forming microorganisms to attach and develop. The vegetation reduces the formation of aerosols and exposure to odor compounds. It also serves as habitat for insects and organisms that are beneficial to the system such as snails. This is because they graze on the microbial biomass which reduces sludge and controls the growth of the microbes, ensuring that they are at the optimal level for the system to work properly. (Esi Engineered Solutions. 2005).

The wastewater next enters the clarifier which separates microbial solids (bio solids) from the treated waste water. Some of the bio solids are returned to the anoxic tank to serve as food and to help start the process over again by activating the microbial populations. Any remaining floating solids that have not been recycled are taken out by hand and pumped to the solids holding tank where it will be disposed of. The treated effluent from the clarifier flows to the disinfection reuse system where it is treated and reused in the toilets. (Esi Engineered Solutions. 2005).

The final step in the living machines water treatment process is the disinfection system located in the basement of the Sharon Information Center. The treated wastewater flows by gravity through the clarifier to a surge tank. Within the surge tank is a pump which filters the water through a sand filter. The particulates that the filter catches is sent to the bio solids holding tank, while the effluent form the sand filter flows into the chlorination tank. The water flows by gravity from the chlorination tank to the dechlorination tank. Effluent from this tank passes through a chlorine analyzer into the dechlorination tank and into the recycled water surge tank where blue dye is added to let the public know the water has been disinfected and effectively treated (Esi Engineered Solutions. 2005).

Some benefits of the ecological wastewater treatment is the increase in the diversity of species and different processes that can effectively treat compounds such as Endocrine Disrupting Compounds (EDC’s) that normal wastewater treatment processes cannot. The Environmental Protection Agency does not regulate the amount of EDC’s and other pharmaceuticals that go into our drinking water but that does not mean that EDC’s are safe. “Endocrine disrupting compounds are of particular concern because of their ability to interfere with biological signaling mechanisms that govern development, reproduction, or immune function” (Shi, W.Wang pg. 1). EDC’s are also proven to have a direct negative effect on wildlife such as disrupting the sexual orientation in male birds and fish. The diversity of plants and aquatic life as well as the selective growth of certain microorganisms enables the ecological treatment process to breakdown rigorous compounds such as EDC’s. Stimulants like caffeine, anti-inflammatory pharmaceuticals like Naproxen and Ibuprofen and anticoagulants like Warfarin have all been shown to be reduced severely at the ecological wastewater treatment facility in Sharon, Vermont (Shi, W., Wang, L. 2011) (Will Kirksey, PE. 2009).

Other benefits include a reduction in energy demand. Compared too many conventional wastewater treatment systems many ecological treatment systems use only 10 to 20% of the energy required to operate traditional waste water facilities. This is achieved by the reduction in the amount of water that has to be moved long distances. In an ecological wastewater treatment facility the water is moved by gravity and the tanks are in close proximity. (Will Kirksey, PE. 2009)

The challenge then becomes tailoring a system in which all needed living system components may interact without excess competition, while producing water suitable for re-use. Unfortunately, at this time the direct interaction and mechanism for removal of many pharmaceuticals, along with the fact that many of these chemicals are either intrinsically isolated for the purpose of inhibiting cell activity (antibacterials), are complex molecules that are not commonly broken down by micro-organisms, or are synthetically created from atomic components that are foreign from biologic use (xenobiotics), is a direct issue of concern for the future of water quality. Better understanding of how Ecologic Wastewater Treatment Systems interact with PPCP’s based on selected biological components will contribute to the diversity of waste that can be handled effectively.

The basic objection of this study was to determine if any correlation exists between the effects of a given medication or drug and how well it is filtered by the Living Machine. The analysis of samples from both the Influent material being delivered to the Living Machine and the Effluent water produced by the filtration shows an overall trend for reduction in chemicals present, though some are more readily removed by the process.

Methods:

The Sharon Eco-Machine is broken down into a series of cells, each with a unique function in treating wastewater. For the initial portion of this study, it will be necessary to ascertain whether or not the system as a whole is effective in removing estrogens from the waste stream. To do this, water will be sampled as it enters the treatment room. Because the target compounds are expected to be present only in minute quantities (parts per billion), solid-phase micro-extraction (SPME) will be utilized to gather samples. The same sampling technique will be used at the effluent of the Eco-Machine. In the lab, these samples will be analyzed for the presence of 17α-ethinylestradiol, 17β estradiol, and estrone.

The Sharon Eco-Machine is located at a rest area on U.S. Interstate 89. As such, the volume of wastewater treated varies with the volume of traffic. During the summer and peak foliage seasons, when tourism is high, the Eco-Machine treats a large volume of wastewater. Use of the Eco-Machine is lower during the off-season of late November through early December. To develop a clear profile of the performance efficiency of the Sharon Eco-Machine across a variety of flow rates, samples will be gathered (monthly, bi-monthly?) during the months of August through January.

Results:

At first glance of the majority of the effectively filtered molecules, it can be seen that the most readily removed were the analgesic and antibacterial compounds. The mechanisms for reduction of these compounds are related to the digestion of material by the bacteria present within the reactor vessels of the machine. The most dramatic instance of reduction is for caffeine, which was found to be the highest concentration of sampled drug being introduced through the Influent, but also showed the most drastic reduction when compared to the amount present in the Effluent stream.

Discussion:

The most abundant chemical found in the samples was caffeine. Caffeine acts as a central nervous system stimulant, temporarily warding off drowsiness and restoring alertness. It is most commonly ingested in the form of drinks. It is consumed through the form of coffee, tea, soft drinks, and energy drinks. Caffeine is the worlds most consumed psychoactive drug. Around 90% of American adults consume caffeine daily. It can also be taken as a medicine to reduce fatigue and to make you more alert.

Another class of medication found anticonvulsants. They work by reducing the any abnormal electrical activity in the brain. There were two chemicals found in the samples that were anticonvulsants. Phenytoin is a medicine used to control certain types of seizures, and to treat and prevent seizures that may begin during or after surgery to the brain or nervous system. Also it is prescribed to treat an irregular heartbeat. It is taken orally two to three times a day. Phenytoin is found as the brand names Di-Phen, Dilantin, and Phenytek. Carbamazepine can be used alone or with other medications for the control of seizures. Also it is used for controlling bipolar disorder. Like Phenytoin it is taken orally and twice a day with meals. Carbamazepine is found as Carbatrol, Epitol, and a few others.

One form of anticoagulants was found in the sampling. Also anticoagulants are commonly called blood thinners. Warfarin is a medicine used to prevent blood clots from forming or growing larger in your blood vessels. Also used for patients with heart problems such as irregular heartbeat, prosthetic heart valves, and heart attacks. Warfarin is taken daily orally. Warfarin is known as Coumadin, Jantoven, and Marfarin.

This group of chemicals is NSAIDs or Nonsteroidal anti-inflammatory drugs. Naproxen is used to relieve pain, tenderness, swelling, and stiffness caused by osteoarthritis. It is commonly known as Aleve. It is taken one to two times daily by mouth. Ibuprofen is used to relieve pain, tenderness, swelling, and stiffness caused by osteoarthritis. Ibuprofen is taken three to four times a day orally. Salicylic acid is known for its ability to ease aches and pains and reduce fevers. A common known form of Salicylic acid is Aspirin. Salicylic acid is taken up to three to four times daily by mouth.

This class of chemicals is known as analgesics, and antipyretics. They are pain relievers and fever reducers. Acetaminophen is used to relieve mild to moderate pain from headaches, muscle aches, menstrual periods, colds and sore throats, toothaches, backaches, and reactions to vaccinations, and to reduce fever. Acetaminophen can be taken daily orally or rectally. The brand names of Acetaminophen are Acephen, Aceta, and a few more.

Another fairly abundant chemical found was fibrates which are lipid regulating medications. Gemfibrozil is used with diet changes to reduce the amount of cholesterol and triglycerides in the blood. It is used to increase the blood flow and provide more oxygen to your body. It is taken orally twice daily, thirty minutes before breakfast and thirty minutes before dinner. The common forms of Gemfibrozil are Gemcor and Lopid.

The next chemical group found was antibiotics. Sulfamethoxazole it is commonly used to treat urinary tract infections, sinusitis, and pneumonia. Trimethoprim eliminates bacteria that cause urinary tract infections. The two medicines are used together as one part trimethoprim to five parts Sulfamethoxazole. It is commonly known as Bactrim, Biseptol, and a number of others. It is taken one to two times daily orally.

More curious than the disintegration of antibacterial compounds is that the two anti-psychotics that were tested and present in both samples were not broken down, and in the case for Phenytoin actually increased in concentration, which is likely resulted due to sampling the influent and effluent on the same day despite there being a 48 hour residence time of water in the system. Therefore the effluent sample water represents inputs 48 hours prior. Because these compounds are not being metabolized, they remain in the water discharged from the system and remain in the water, where they could potentially reach higher concentrations through recirculation of effluent water being used for flushing. It has been found that introducing Typhaspp. can increase the amount of Carbamazepine removal up to 97% (Removal of pharmaceuticals, Dordio A). Presently, little is known about the interaction of multiple chemicals within effluent streams, as the combinations of certain molecules can lead to synergistic compounds of potentially increased toxicity and a more complex mixture to be processed and dealt with (Monosson, 2005). Because of this it is hard to determine a single reason as to why specifically the anti-psychotic medications were the least up-taken through the process. One possible explanation for this may be the presence of carboxyl-nitride groups that may be difficult for life forms to process, though it must be noted that the same groups exist within the caffeine molecule. The imidazole molecule incorporated in the Phenytoin molecule is used to derive antifungal properties, whereas the purine component of caffeine is part of many common biological molecules including nucleic acids. The deactivating nature of nitrogen bonded to and included in cyclic aromatic ring structures may also contribute to the low rate of metabolized carbamazepine and phenytoin.

Structurally, Carbamazepine and Phenytoin are similar in that they both contain a carbonyl group flanked by two nitrogen atoms (Table 2 J, K). It must be added that the caffeine molecule also includes similar structures, yet was the most processed molecule by the living machine. Such examples of interactions only fuel the need for further understanding of how chemicals in effluent matter are managed.


Conclusions: By studying the effect of various plant species in combination and their effectiveness at purifying water, better systems can be developed to restore clean water for the safe applications of life and environment. Although not all PPCP’s are being removed from the system effluent, the amount of filtration actively happening at this point is comparable or greater than that of a mechanical system, yet room for improvement exists without the need for large scale redesigns if the system components.

References:

-“Removal of pharmaceuticals in microcosm constructed wetlands using Typha spp. and LECA” Dordio ACarvalho AJTeixeira DMDias CBPinto AP. Bioresour Technol. 2010 Feb;101(3):886-92. Epub 2009 Sep 23. http://www.ncbi.nlm.nih.gov/pubmed/19783427

-“Treating Contaminants of Emerging Concern” American Water Works Association Research

Foundation. EPA August 2010. http://water.epa.gov/scitech/swguidance/ppcp/upload/cecliterature.pdf

-“Chemical Mixtures: Considering the Evolution of Toxicology and Chemical Assessment” Monosson, Emily. Environmental Health Perspectives, Volume 113 Number 4 April 2005.

-“Effects of Plants and Microorganisms in Constructed Wetlands for Wastewater Treatment”. A. Wießner, P. Kuschk, U. Kappelmeyer, M. Kästner, O. Bederski, R.A. Müller, H. Moormann. Biotechnology Advances Volume 22, Issues 1–2, December 2003, Pages 93–117. http://www.sciencedirect.com/science/article/pii/S0734975003001319

- “The Design of Living Technologies for Waste treatment” John Todd, Beth Josephson. Ecological Engineering6 (1996) 109-136. Received 4 March 1994; revised 14 July 1995; accepted 5 September 1995. http://www.uvm.edu/rsenr/nr385c/resources/documents/The%20design%20of%20living%20technologies%20for%20waste%20treatment.pdf

Esi Engineered Solutions. (2005). Operations and Maintenance Manuel Living Machine System for Wastewater Treatment and Reuse. https://files.pbworks.com/download/cQ2A8qUBpf/drbalcom/36864991/Sharon%20O&M%202005%20-%20November.pdf

Shi, W., Wang, L., Rousseau,. D.P., Lens, P.N. Removal of estrone, 17alpha-ethinylestradiol, and 17beta-estradiol in algae and duckweed-based wastewater treatment systems. Environmental Science and Pollution Research International. 4. 824-833. Retrieved from www.ncbi.nlm.nih.gov.

Will Kirksey, PE. (2009). Creating a Sustainable Water Infrastructure for the 21st Century. http://www.livingmachines.com/images/uploads/resources/Final_LM_White_Paper.pdf.

 

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