Difference between revisions of "Team:Calgary/Human Practices"

 
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<p>The team focused on evaluating the feasibility of the 4 proposed project applications: production of PHB on Mars from human waste, integrating PHB production in a wastewater treatment plant, integrating PHB production with leachate treatment, and integrating PHB production in developing countries. Our subgroup calculated the approximate amount of PHB that would be expected in each scenario.</p>
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<p>The team focused on evaluating the feasibility of four proposed project applications: integrating PHB production with landfill leachate treatment, integrating PHB production in a wastewater treatment plant, integrating PHB production in developing countries, and the production of PHB on Mars from human waste.</p>
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<p><h2><div id="Icons"><img src="https://static.igem.org/mediawiki/2017/2/23/Calgary2017_LandfillsIcon.png"> </div> &ensp; Landfills</h2></p>
 
<p><h2><div id="Icons"><img src="https://static.igem.org/mediawiki/2017/2/23/Calgary2017_LandfillsIcon.png"> </div> &ensp; Landfills</h2></p>
<div id="Caption"><b>Figure 1 and 2: </b> Photos from the tour of the wastewater treatment facilities in Calgary in June.</div>
 
  
<p>Landfill leachate treatment is an avenue that our team considered when looking at possible applications of our project on Earth. Leaches make up feedstock that is rich with organic matter. Leaches are highly toxic waters produced during the decomposition of waste. This waste becomes dangerous to the environment when left untreated and can leak to the groundwater, causing contamination. The impurities found in leachate can be classified into 3 major groups: dissolved organic matter, inorganic macrocomponents, heavy metals and xenobiotic organic compounds. Leachate from young landfills look particularly promising as a choice of feedstock due to its high chemical oxygen demand (COD), which is found to be greater than 10 000 mg/L, while in the older landfills the COD decreases to less than 4000mg/L.</p>
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<p>Landfill leachate treatment is an avenue that we considered when looking at possible applications of our project on Earth. Leachate is the fermented runoff liquid that accumulates underground at landfills, and as a feedstock, it is rich in organic matter. It is highly toxic and becomes dangerous to the environment when left untreated as it  can leak into nearby groundwater, causing contamination.</p>
<p>The integration of PHB production in <b>leachate treatment</b> would likely be unfeasible due to low volumes of leachate that are usually produced at landfills. In Calgary, a single landfill generates about 100,000 L of leachate per day. Although COD content in leachate is higher than in wastewater, the estimated amount of PHB produced in Calgary was about 8000 kg/year, based on COD content of 1977 mg/L in Calgary leachate (Kashef & Lungue, 2016). This would result in about $40,000 in revenue, assuming a price of $5 per kg of PHB (Manufacturing and properties of PHB, 2017) . Another member of the team performed similar calculations assuming 0.38 grams of PHB produced per gram of VFA, which resulted in 22,250 kg of PHB per year and a potential revenue of $111,126 per year.The cost of implementing a PHB production process will likely be magnitudes larger. Leachate treatment in China is a more promising alternative. China generates a larger amount of leachate compared to many other countries. ("Leachate treatment in China: Technologies and Import Opportunities", 2015) Additionally, the COD content in Hong Kong, China ranges from 15,700 to 50,000 mg/L for young landfills ("Leachate treatment in China: Technologies and Import Opportunities", 2015), which is 8 to 25 times greater than in Calgary. We estimated that about 900,000 - 3,000,000 kg of PHB can be produced per year in Hong Kong depending on COD content and using PHA yield of 0.11 kg of PHA per kg of COD. PHB production from leachate was also considered for Vancouver, which generates 2,225,978 cubic meters of leachate per year (Vancouver landfill 2016 annual report, 2017). Based on our estimates, about 3,100,000 kg of PHB can be produced per year assuming the COD content of about 13,000 mg/L (Tao et al., 2005)</p>
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<p>Conventional technologies used in leachate treatment do not include the production of value-added products, and current technologies appear to be concerned with the simple removal of toxic, undesired components. Leachate transfer methods include recycling and combining it with the treatment of domestic sewage, biodegradation for waste decomposition, and chemical and physical methods involving oxidation, adsorption, chemical precipitation, coagulation/flocculation, sedimentation/flotation and air stripping. Integrating a PHB-producing stage into conventional leachate treatment would facilitate the production of PHB out of the waste, cutting down the cost of treatment and allowing the facilities to become profitable. One problem associated with this feedstock is can be contaminated with heavy metals, which decreases the rate of growth and PHB production in our bacteria. This would mean that the leachate would have to be treated to remove heavy metals prior to fermentation with our bacteria, and is a costly process.</p>
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<div id="Caption"><b>Figures 1 and 2: </b> Photos from a tour of the Pine Creek Wastewater Treatment Plant in Calgary in June, 2017.</div>
  
<p>Our project was initially aimed at providing a method by which <b>wastewater treatment facilities</b> could take biological material in wastewater and transform it into value-added product in the form of bioplastic. Part of our integrated human practices included a visit to our local wastewater treatment facility.</p>
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<p>Our project also had the potential to provide a method by which wastewater treatment facilities could take the biological material in wastewater and transform it into a value-added product. Part of our Integrated Human Practices included a visit to our local wastewater treatment facility. Pine Creek is a new wastewater treatment facility in Calgary, which treats sludge to produce methane and uses the treated sludge as a fertilizer.</p>
<p>For the wastewater treatment plant, we estimated 28,100,000 kg of PHB produced per year. The Pine Creek Wastewater Treatment Plant in Calgary processes about 1 million cubic meters of waste per day. The COD content and PHA yield were assumed to be 1000 mg/L and 0.11 kg of PHA per kg of COD, respectively, for the calculations.</p>
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<p>This tour served the purpose to gather information regarding this application. Sludge produced during conventional municipal wastewater treatment is a nutrient-rich material that looks promising for the PHB production industry. Currently, sludge is treated to remove organic matter and toxins. Removal of organic matter is achieved by fermentation, where the organic matter is broken down into volatile fatty acids (VFAs) and is afterward digested by bacteria to produce methane and carbon dioxide. We researched on the use of sludge as a feedstock for PHB production and showed the process to be feasible, but not yet economical. One of the major downsides of industrial-scale PHB production is the use of toxic chemicals - chloroform in the extraction and purification of PHB bioplastic. We also found that along with the extraction and purification expenses, the profitability of this option was not ideal.</p>
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<p><h2><div id="Icons"><img src="https://static.igem.org/mediawiki/2017/f/f6/Calgary2017_DevelopingCountriesIcon.png"> </div> &ensp; Developing Countries</h2></p>
 
<p><h2><div id="Icons"><img src="https://static.igem.org/mediawiki/2017/f/f6/Calgary2017_DevelopingCountriesIcon.png"> </div> &ensp; Developing Countries</h2></p>
  
<p>In developing countries, we envisioned PHB production incorporated into scaled-down wastewater treatment systems in small communities that lacked established treatment methods. Selling PHB would provide monetary incentive to construct a wastewater treatment system, which, in turn, will reduce diseases due to poor sanitation. Additionally, we wanted to compare PHB production between genetically engineered bacteria and natural bacterial communities in sludge, which have been previously used to feasibly produce PHB. Assuming a community size of 2000 people, solid waste generation of 3.113 x 10<sup>-3</sup> m<sup>3</sup>/day/person (Palanivel & Sulaiman, 2014), COD content of 601 mg/L, COD to PHB conversion of 0.11 for mixed cultures and 0.88 for pure cultures  (Rhu et al., 2003) and a price of $5 per kg of PHB (Choi & Lee, 1997), we found that using pure cultures results in additional $2,000 in revenues. However, the cost of sterilization of waste stream before inoculation with pure culture was estimated at $100,000 (Choi & Lee, 1997).</p>
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<p>After learning that wastewater treatment was not profitable, we turned our focus to developing countries. Since the first two applications we considered were of greater concern in the developing world than in areas where effective wastewater treatment and plastic recycling already exist, we decided to look into implementing our system as a small-scale wastewater treatment option for communities in the developing world. Selling PHB would provide a monetary incentive to construct a wastewater treatment system, which, in turn, will reduce the incidence of water-borne disease. Challenges arise concerning the cost of our product and the lack of a user-friendly platform.</p>
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<p><h2><div id="Icons"><img src="https://static.igem.org/mediawiki/2017/4/41/Calgary2017_MarsIcon.png"> </div>&ensp; Space</h2></p>
 
<p><h2><div id="Icons"><img src="https://static.igem.org/mediawiki/2017/4/41/Calgary2017_MarsIcon.png"> </div>&ensp; Space</h2></p>
  
<p>We approximated that about 40 - 90 kg of PHB can be produced on Mars per year with a crew of 6 astronauts. A crew of 6 will generate about 6 tonnes of solid organic waste over 2.5 years (Zhang et al., 2015). Reported COD content in feces was found to be 354 mg COD per gram of wet human waste (Rose et al., 2015). One study looking at PHA production from food waste estimated the yield of 0.05 g of PHA per g of COD applied (Rhu et al., 2003). Another study reported 0.11 kg of PHA produced per kg of effluent COD in a PHA production process from activated sludge (Bengtsson et al., 2008). The predicted PHB range was based on COD to PHA conversion. Another member of the team assumed the average COD content in human excretions to be 61.75 g/cap/day (Rose et al., 2015), the COD to VFA ratio of 0.74 (Coats et al., 2011)and the VFA to PHB conversion of 0.38 g PHA/g VFA ,(Coats, VandeVoort, Darby & Loge, 2011) which resulted in 41 kg of PHA per year per crew of 6. According to NASA, the cost of shipping supplies to space using SpaceX Dragon spacecraft is $27,000 per pound. The costs saved by producing 41 kg of PHA in space would then be about $2,440,000. We also contacted a 3D printing company called 4G Vision Tech that uses selective laser sintering (SLS), which can be used to 3D print with PHB (Pereira et al., 2012). Howard from 4G Vision Tech approximated that the predicted amount of PHB can be used to create approximately 50 hydroponic systems and 20 general tools like wrenches, hammers, and scissors.</p>
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<p>While the previously-mentioned wastewater feedstock is a promising source of VFAs, the cost of implementation in current treatment facilities is high. In addition, the control of naturally-existing bacteria in the wastewater is inadequate, meaning a pure culture of our engineered <i>E. coli</i> would be outcompeted.
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<p>The implementation of our PHB production process in space is a novel solution in the treatment of the solid human waste. Currently, human waste is left untreated and is transported back to Earth where it burns upon re-entering the Earth's atmosphere. NASA has been investigating different ways of utilizing human waste during space expeditions and on Mars, yet the use of human stool in the production of PHB was not yet discussed. This encouraged us to look at the project idea as a novel idea worthy of investigation. Furthermore, the high level of sterility of the process supports the growth of pure bacterial culture. Even more, the PHB produced in space can then be used in Selective Laser Sintering (SLS) 3D printing necessary tools on demand. </p>
  
  

Latest revision as of 03:45, 2 November 2017

Header

Human Practices

Click on the icons to learn more!
WasteWater Landfills DevelopingCountries Space WasteWater Landfills DevelopingCountries Space WasteWater Landfills DevelopingCountries Space WasteWater Landfill DevelopingCountries Space

The team focused on evaluating the feasibility of four proposed project applications: integrating PHB production with landfill leachate treatment, integrating PHB production in a wastewater treatment plant, integrating PHB production in developing countries, and the production of PHB on Mars from human waste.


  Landfills

Landfill leachate treatment is an avenue that we considered when looking at possible applications of our project on Earth. Leachate is the fermented runoff liquid that accumulates underground at landfills, and as a feedstock, it is rich in organic matter. It is highly toxic and becomes dangerous to the environment when left untreated as it can leak into nearby groundwater, causing contamination.

Conventional technologies used in leachate treatment do not include the production of value-added products, and current technologies appear to be concerned with the simple removal of toxic, undesired components. Leachate transfer methods include recycling and combining it with the treatment of domestic sewage, biodegradation for waste decomposition, and chemical and physical methods involving oxidation, adsorption, chemical precipitation, coagulation/flocculation, sedimentation/flotation and air stripping. Integrating a PHB-producing stage into conventional leachate treatment would facilitate the production of PHB out of the waste, cutting down the cost of treatment and allowing the facilities to become profitable. One problem associated with this feedstock is can be contaminated with heavy metals, which decreases the rate of growth and PHB production in our bacteria. This would mean that the leachate would have to be treated to remove heavy metals prior to fermentation with our bacteria, and is a costly process.


  Wastewater Treatment Plants

Figures 1 and 2: Photos from a tour of the Pine Creek Wastewater Treatment Plant in Calgary in June, 2017.

Our project also had the potential to provide a method by which wastewater treatment facilities could take the biological material in wastewater and transform it into a value-added product. Part of our Integrated Human Practices included a visit to our local wastewater treatment facility. Pine Creek is a new wastewater treatment facility in Calgary, which treats sludge to produce methane and uses the treated sludge as a fertilizer.

This tour served the purpose to gather information regarding this application. Sludge produced during conventional municipal wastewater treatment is a nutrient-rich material that looks promising for the PHB production industry. Currently, sludge is treated to remove organic matter and toxins. Removal of organic matter is achieved by fermentation, where the organic matter is broken down into volatile fatty acids (VFAs) and is afterward digested by bacteria to produce methane and carbon dioxide. We researched on the use of sludge as a feedstock for PHB production and showed the process to be feasible, but not yet economical. One of the major downsides of industrial-scale PHB production is the use of toxic chemicals - chloroform in the extraction and purification of PHB bioplastic. We also found that along with the extraction and purification expenses, the profitability of this option was not ideal.


  Developing Countries

After learning that wastewater treatment was not profitable, we turned our focus to developing countries. Since the first two applications we considered were of greater concern in the developing world than in areas where effective wastewater treatment and plastic recycling already exist, we decided to look into implementing our system as a small-scale wastewater treatment option for communities in the developing world. Selling PHB would provide a monetary incentive to construct a wastewater treatment system, which, in turn, will reduce the incidence of water-borne disease. Challenges arise concerning the cost of our product and the lack of a user-friendly platform.


  Space

While the previously-mentioned wastewater feedstock is a promising source of VFAs, the cost of implementation in current treatment facilities is high. In addition, the control of naturally-existing bacteria in the wastewater is inadequate, meaning a pure culture of our engineered E. coli would be outcompeted.

The implementation of our PHB production process in space is a novel solution in the treatment of the solid human waste. Currently, human waste is left untreated and is transported back to Earth where it burns upon re-entering the Earth's atmosphere. NASA has been investigating different ways of utilizing human waste during space expeditions and on Mars, yet the use of human stool in the production of PHB was not yet discussed. This encouraged us to look at the project idea as a novel idea worthy of investigation. Furthermore, the high level of sterility of the process supports the growth of pure bacterial culture. Even more, the PHB produced in space can then be used in Selective Laser Sintering (SLS) 3D printing necessary tools on demand.

Engagement

Collaborations