From Living Building Science
The Living Building Challenge imposes a rigorous set of standards for the most sustainable buildings in the world. Living Buildings are required to account for all 7 Petals of the Living Building Challenge: Place, Water, Energy, Health and Happiness, Materials, Equity, and Beauty. The Kendeda Building at Georgia Tech is in the process of certification by the Living Building Challenge, and is the first Living Building of its size and purpose. One of the main systems in the building is the greywater system which uses a constructed wetland to filter Greywater. Greywater wetland systems are still a relatively uncommon way for buildings to filter water from sinks, water fountains, showers, and other non-"black water" sources due to high cost, contamination risks, and the ease of putting greywater into the sewer system. However, if implemented correctly they can help clean greywater to acceptable standards for irrigation of non-edible plants and increase groundwater recharge. Our goal is to investigate the greywater system and test its overall filtration effectiveness.
System of Study
The greywater system filters greywater from the Kendeda Building, and releases the filtered water into groundwater reservoirs. Greywater from the Kendeda Building includes water from sinks, showers, and water fountains. The water flows from its source to a large cistern that is located in the back of the Kendeda Building, where it is temporarily stored. Water is then gradually pumped uphill to the constructed wetland that is located in the front of the Kendeda Building. The water finally moves through the wetland horizontally and is filtered using sediment, gravel, and local aquatic plants.
List of plants in the constructed wetland :
- Sphoenoplectus tabernaemontani
- Softstem Bulrush
- Pontederia cordata
- Typha latifolia
- Broadleaf Cattail
- Arisaema triphyllum
- Jack in the Pulpit
- Lysmachia terrestris
- Swamp Candle
Many areas utilize natural wetlands to help filter wastewater. Not only are wetlands used for filtration, many are home to a large biodiversity of plants and animals. Many water treatment wetlands also serve as wildlife sanctuaries. For example, the Arcata Marsh in Arcata, California. The Arcata Marsh was a wetland restoration project to reclaim lost marshland. This is an example of how wastewater can be used as a resource rather than a waste. It can be used to grow extremely biodiverse wetlands and restore ecosystems. While Kendeda's constructed wetland is a much smaller scale, the constructed wetland is making a miniature ecosystem on the building's perimeter.
Another similar system that is closer to Atlanta, Georgia is the Constructed Wetland Treatment System in Fort Deposit, Alabama. The system includes two separate constructed wetlands, side by side, that allows water to flow through them horizontally. The system was proven to meet water treatment standards, and it also promoted more biodiversity in the area.
Measurements of water quality from the start and end of the greywater system will decrease due to a variety of factors including possible evaporation and time for bacterial growth in the septic tank.
Evaluate effectiveness of the Kendeda Building’s Greywater filtration system by obtaining the following data from water at the inflow and outflow sample points.:
- Depth/Volume in greywater tank and in constructed wetland
- Total dissolved solids (TDS)
- Dissolved oxygen (DO)
Observe temporal changes in the chemical composition of the water samples.
- FAAS (Flame Atomic Absorption Spectroscopy)
- DNA analysis in collaboration with Joel Kostka lab and Ph.D. students in Biology Department.
The following procedure will lay out how the sample taken from the input tank will be collected and analyzed in the lab.
1. The lid will be removed using a ratchet kit, being sure to not contaminate the bottom of the lid with other matter surrounding the tank opening. Then a 1 gallon sample is removed from the septic tank using a "throw bucket."
- Another option would be to hold up the lid without removing it completely and collect a sample using a throw bucket.
2. Immediately upon collecting the water sample, temperature, pH, TDS, and DO data will be collected directly from the bucket using pre-calibrated electrodes. This information will then be recorded.
3. A 30 mL syringe will be used to collect 4-(50 mL) aliquots from the throw bucket. In the end, there should be 4 test tubes containing 50 mL of water samples. The test tubes will be labeled as follows:
- Filtered acidified
- Filtered unacidified
- Unfiltered acidified
- Unfiltered unacidified
- The acidified samples will be acidified to pH 2.
4. After collected water samples, the lid will be replaced, making sure it is secure. Be care to NOT OVERTIGHTEN THE BOLTS.
5. The collected water samples will be taken back to the lab and bacteria will be filtered out.
6. If immediate analyses of the samples is not able to be done, the samples should be kept frozen until testing can be done.
- Danger in obtaining samples from open/exposed tank (fall hazards attributed to underground storage tank)
- Exposure to pathogens
- Collecting samples in an active construction zone
- Will need constant supervision from the construction site manager
- Will need hard hats, vests, and other protective equipment
Arden, S, and X Ma. “Constructed Wetlands for Greywater Recycle and Reuse: A Review.” Science of the Total Environment, vol. 630, 2018, pp. 587–599.
- This is a review of a case study done to see if constructed wetlands meet the microbiological standards for water reuse. They measured pathogens, E. Coli, BOD, and other metrics. From their study, they concluded that the constructed wetland is unable to meet standards on its own. However, the wetland combined with ultraviolet radiation and chlorination could meet standards for water reuse.
Carleton, J., Grizzard, T., Godrej, A., Post, H., Lampe, L., & Kenel, P. (2000). Performance of a Constructed Wetlands in Treating Urban Stormwater Runoff. Water Environment Research, 72(3), 295-304. Retrieved February 26, 2020, from www.jstor.org/stable/25045379
- This study looked at the performance of constructed wetlands in northern Virginia of removing pollutants from stormwater runoff. More specifically, the study focused on stormwater runoff from a residential townhome complex. Researched collected data from 33 runoff events from April 1996 to May 1997, and results generally showed positive pollutant removal levels.
Cooper, R. (2008). Going Grey. Landscape Architecture Australia,(117), 75-77. Retrieved February 26, 2020, from www.jstor.org/stable/45142506
- This is a brief but interesting report on how Australia is trying to use greywater for gardening. The report provides a short summary on what greywater is and what potential hazards could come from using it. By properly regulating its use, then residents would be able be less water intensive and use it in a much more efficient way.
Crites, R., Dombeck, G., Watson, R., & Williams, C. (1997). Removal of Metals and Ammonia in Constructed Wetlands. Water Environment Research, 69(2), 132-135. Retrieved February 26, 2020, from www.jstor.org/stable/25044854
- This older paper from 1997 discusses how constructed wetlands have to potential to remove toxic metals and ammonia from the water. This experiment was conducted from July 1994 to December 1995, and researchers indicated significant removal of 13 metals, some of which include lead, copper, and zinc. The main vegetation used in this experiment was bulrush and some cattail.
Dixon, A. M., Butler, D., & Fewkes, A. (1999). Guidelines for Greywater Re-Use: Health Issues. Water and Environment Journal, 13(5), 322–326. doi: 10.1111/j.1747-6593.1999.tb01056.x
- This 1999 paper reviews the possible threats that grey water reuse can pose. It reviews the risks and provides modified guidelines taking into consideration public health. The paper recommends that faecal coliform should be used as an indicator of microbe quality. One key observation from the paper is that residence time in the system should be kept at a minimum. Thus things like septic tanks can cause adverse health effects due to microbial proliferation.
EPA. (1993). Constructed Wetlands for Wastewater Treatment and Wildlife Habitat. Retrieved April 20, 2020. https://www.epa.gov/wetlands/constructed-wetlands-wastewater-treatment-and-wildlife-habitat-17-case-studies
- This article discusses various constructed wetlands. Although it is a bit dated, it provides some good comparisons for our system.
Hernandez Leal, L., Temmink, H., Zeeman, G., & Buisman, C. J. N. (2010). Comparison of Three Systems for Biological Greywater Treatment (Vol. 2, pp. 155-169): Water.
- This source analyzes the effectiveness of three separate greywater treatment methods: “aerobic treatment in a sequencing batch reactor, anaerobic treatment in an up-flow anaerobic blanket reactor and combined anaerobic-aerobic treatment”. They collected greywater from 32 homes, and transferred to a lab for treatment in lab-scale reactors. The study noted that aerobic greywater treatment proved more beneficial than anaerobic treatment, as it removed 90% COD and 97% anionic surfactants compared to only 51% COD removal and 24% anionic surfactant removal in anaerobic conditions.
Paulo, P. L., Begosso, L., Pansonato, N., Shrestha, R. R., & Boncz, M. A. (2009). Design and configuration criteria for wetland systems treating greywater. Water Science and Technology, 60(8), 2001–2007. doi: 10.2166/wst.2009.542
- The goal of this research was to design a grey-water wetland for a household and then determine whether the criteria used for design was appropriate. The paper shows the strengths, weaknesses and potential for household grey-water wetlands using current criteria.
Ramprasad, C, et al. “Removal of Chemical and Microbial Contaminants from Greywater Using a Novel Constructed Wetland: GROW.” Ecological Engineering, vol. 106, no. PA, 2017, pp. 55–65.
- GROW (Green Roof-Top Water Recycling System) located in southern India. This source has some good data on quantities we would like to measure such as pH, BOD, and others. An interesting note is that their system was more efficient, especially removing BOD, during summer months.
Ramprasad, C, and Ligy Philip. “Surfactants and Personal Care Products Removal in Pilot Scale Horizontal and Vertical Flow Constructed Wetlands While Treating Greywater.” Chemical Engineering Journal, vol. 284, 2016, pp. 458–468.
- This is a study for how effective constructed wetlands are at removing pollutants from greywater. Interestingly, they concluded that vertical flow wetlands are marginally more effective than horizontal flow wetlands. The chemicals and procedures they used to analyze the water could be useful for our experiment.
Robinson, D. (1994). Tansley Review No. 73. The Responses of Plants to Non-Uniform Supplies of Nutrients. The New Phytologist, 127(4), 635-674.
- This source analyzes plant response to a non-uniform nutrient supply. Since we believe that the constructed wetland is not receiving enough nutrients, this source will be helpful in predicting an understanding of the response of the wetland species to a lack of essential nutrients. The specific nutrients covered by this source include ammonium, nitrate, potassium, and phosphorus. Of these four nutrients, we will be testing the constructed wetland for three of them: nitrate, ammonium, and phosphate.
Winward, G. P., Avery, L. M., Frazer-Williams, R., Pidou, M., Jeffrey, P., Stephenson, T., & Jefferson, B. (2008). A study of the microbial quality of grey water and an evaluation of treatment technologies for reuse. Ecological Engineering, 32(2), 187–197. doi: 10.1016/j.ecoleng.2007.11.001
- This source analyzes how microbes grow in different types of grey water wetlands. They compared the development of different pathogens in grey water wetland systems to development in traditional water treatment systems. The wetlands did not perform as well as traditional systems, but the most effective wetland was a vertical flow reed bed (VFBR).
|Jacob Varner||Civil Engineering||January 2020 - Present|
|Christina Lu||Earth & Atmospheric Sciences||January 2020 - Present|
|Samantha Brewer||Civil Engineering||January 2020 - Present|
|Donald Gee||Civil Engineering||January 2020 - Present|