From Living Building Science
This page will describe the goals of the Greywater Wetland team as part of Georgia Tech's Living Building Science VIP Team. This subteam focuses on analyzing the efficiency of the greywater filtering system of the constructed wetland located at the front of the Kendeda Living Building, and using geochemical analysis to assess the efficiency of filtering of the building's greywater.
System of Study
The greywater system filters greywater from the Kendeda Building, and it releases the water back into the groundwater reservoirs. Greywater from the Kendeda Building includes water from sinks, showers, and water fountains. First, greywater is collected in a large cistern that is located in the back of the Kendeda Building. There, the greywater is stored temporarily. Water is gradually pumped uphill to the constructed wetland that is located in the front of the Kendeda Building. The water moves through the wetland horizontally and the water is filtered naturally by 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
Used to remove pollutants and toxic metals
Implement grey water filtering systems for residential households
Use of greywater for gardening
Plant growth will be affected by uneven nutrient distribution from the grey water
The water quality filtered from the constructed wetlands will be worse than the input water due to evaporation and the nature of this closed system.
Evaluate effectiveness of Kendeda Building’s Greywater filtration system with the constructed wetland in front of the building
Obtain data on the following species from inflow vs. outflow water:
- 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
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.
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).