Grantee Research Project Results
Final Report: Improved Biosand Filters by Enhanced Monitoring and Data Collection Methods
EPA Grant Number: SU835515Title: Improved Biosand Filters by Enhanced Monitoring and Data Collection Methods
Investigators: Nguyen, Thanh (Helen) H. , Wang, Hanting , Dong, Shengkun , Sadi, Nora , Pugh, Charles , Vasey, Megan , Densler, Allison
Institution: University of Illinois Urbana-Champaign , Centre for Affordable Water and Sanitation Technology , Environment and Public Health Organization (ENPHO)
EPA Project Officer: Packard, Benjamin H
Phase: I
Project Period: August 15, 2013 through August 14, 2014
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2013) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Safe and Sustainable Water Resources , P3 Awards , Sustainable and Healthy Communities
Objective:
Biosand filters (BSFs) are intermittently-operated slow sand filters for household use designed by the Centre for Affordable Water and Sanitation Technology (CAWST), an international nonprofit organization. They were shown to be an effective, easy-to-use method for improving water quality by removing pathogens, reducing turbidity, and treating a wide range of other contaminants in areas worldwide. Despite their low cost, ease of use, and effectiveness when used according to recommended guidelines by CAWST, implementation of BSFs frequently incurs problems that cause it to be an unsustainable water solution. The technical challenges identified in past studies include both inconsistent usage of BSFs over time and variability of BSF effectiveness between communities using the same water source, suggesting that efficacy relies heavily on user habits. Furthermore, past studies have investigated user patterns only through self-reported home survey methods, making the current available data insufficient to guide a useful BSF redesign. Our objectives are to design a dissolved oxygen sensor setup that can detect and record accurate, real-time data in in-field BSFs, and use this data to (1) identify patterns of user habits and correlate them with BSF pathogen removal and microbial species present inside and throughout the filter, (2) improve user habits to increase pathogen removal, and (3) pinpoint the shortcomings of the current Version 10 BSF design in meeting real world user needs. This data is essential to develop an understanding of realistic BSF user habits because of its unbiased accuracy; therefore, it can be used as a reliable basis to design a new BSF that works effectively under real world use.
In order to achieve our objectives, our project has partnered with CAWST and Environment and Public Health Organization (ENPHO), a local Nepali non-governmental organization (NGO). Our project will directly impact the people and prosperity of the community in the Gorkha district, a mountainous district in the western region of the Gandaki zone in Nepal. The two sites in the district that will be studied are the Batase and Dandidada villages. The population in Batase is 1000 people and in Dandidada, 1200 people, and the majority of community members from both villages are from low caste groups. Both communities use a traditional stone spout from a spring water source for drinking water purposes, however, the water is not potable. The 2010 report by the Gorkha municipality of ENPHO showed high incidence of infectious and noninfectious diarrheal diseases, intestinal worms, and amoebiasis in both communities. In order to alleviate these health issues, ENPHO has formed a collaboration between the University of Illinois at Urbana-Champaign (UIUC) and CAWST to implement BSFs in individual houses. Our project will modify a subset of the filters implemented with sensors that detect and record dissolved oxygen (DO) at three different depths within the filter. The development and testing of this data collection instrument set-up was conducted in Phase I, and implementation in Nepal is proposed for Phase 2. The efficacy of BSFs are tied directly to how well people use them, yet BSF improvement is hindered by social and cultural factors that skew usage data. Improvements to BSF design that incorporate actual, rather than ideal, usage practices will directly improve the lives of millions of people around the world.
Summary/Accomplishments (Outputs/Outcomes):
Figure 1. Sensor Setup Design
Sensor Setup Design
In Phase I of the project, several different DO sensors were researched and considered. In the end, the Atlas Scientific Dissolved Oxygen Sensor was chosen due to its reasonable cost and ability to withstand harsh field environments. A sensor setup was designed that minimizes disturbances of the filter functions and is easy to use in the field (Fig. 1). Three tubes used for water sample collection at different depths (0.8 mm inner diameter) are each filled with mesh at one end to prevent sand from clogging the tubes. The tubes are placed inside the filter to collect and measure DO of water at three different depths (7 cm, 20 cm, and 40 cm). The sensor and three tubes are inserted tightly through a rubber stopper, which is cut to fit tightly inside a plastic tube cut to 10 cm long with a Luer lock at the bottom. The sensor will measure the DO of water samples collected inside the plastic 10 cm tube. A three-way valve is attached to the Luer lock, and a 60 mL syringe is attached to another end of the three- way valve. The 60 mL syringe is pulled to allow water to overcome the hydraulic head in the tube. Clamps are used to ensure water from different tubes do not flow into the plastic tube. The third end of the three-way valve is used to let water collected and tested out into the beaker.
Dissolved Oxygen Data
Preliminary DO data on a newly packed full-scale BSF was collected at three different depths of the filter and is shown in Table 1 below. The filter was run one time each day, which is within the recommended range of usage. Average readings at each minute are documented in a table, and the stabilized readings for each tube are bolded. The preliminary data shows a trend of DO decreasing throughout the filter. This trend is expected because water closer to the top of the filter has been exposed to air longer than water closer to the bottom of the filter. Further DO measurements will be continually collected to determine how DO changes with time in the BSF, and how that affects particular microbial species present throughout the filter that help to increase pathogen removal.
Short Tube (7 cm) | Medium Tube (20 cm) | Long Tube (40 cm) | |||||
Time | DO (mg/L) | Time | DO (mg/L) | Time | DO (mg/L) | ||
March 11 | 12:39 | 5.5 | 12:46 | 4.4 | 12:55 | 4.2 | |
12:40 | 5.3 | 12:48 | 4.8 | 12:56 | 3.7 | ||
12:41 | 5.4 | 12:49 | 4.9 | 12:57 | 3.6 | ||
12:42 | 5.4 | 12:50 | 4.7 | 12:58 | 3.6 | ||
12:43 | 5.4 | 12:51 | 4.7 | 12:59 | 3.6 | ||
12:44 | 5.4 | 12:52 | 4.6 | 1:00 | 3.6 | ||
March 12 | 12:17 | 6.7 | 12:24 | 4.8 | 12:32 | 5.4 | |
12:18 | 6.1 | 12:25 | 4.6 | 12:33 | 5.3 | ||
12:19 | 5.7 | 12:26 | 4.6 | 12:34 | 4.9 | ||
12:20 | 5.4 | 12:27 | 4.6 | 12:35 | 4.7 | ||
12:21 | 5.3 | 12:28 | 4.6 | 12:36 | 4.5 | ||
12:22 | 5.3 | 12:29 | 4.6 | 12:37 | 4.3 | ||
12:38 | 4.1 | ||||||
12:39 | 4.1 | ||||||
March 13 | 1:11 | 6.6 | 1:20 | 4.6 | 1:32 | 4.6 | |
1:12 | 6.1 | 1:21 | 4.3 | 1:33 | 4.4 | ||
1:13 | 5.9 | 1:22 | 4.2 | 1:34 | 3.9 | ||
1:14 | 5.6 | 1:23 | 4.0 | 1:35 | 3.6 | ||
1:15 | 5.5 | 1:24 | 3.8 | 1:36 | 3.4 | ||
1:16 | 5.4 | 1:25 | 3.8 | 1:37 | 3.3 | ||
1:17 | 5.4 | 1:26 | 3.7 | 1:38 | 3.3 | ||
1:27 | 3.6 | 1:39 | 3.3 | ||||
1:28 | 3.6 |
Conclusions:
During Phase I, we had three main goals: research and design of the DO sensor setup, student advancement, and education outreach. All three goals were met, and Phase I of our project has been a success. First, a DO sensor setup that meets several aspects proposed (i.e., does not alter the function of BSFs, is able to withstand a flow of 20-40 L of water per day, has a low cost, and requires minimum maintenance) has been designed and tested on a full-scale BSF at UIUC. Although only preliminary data has been collected and further DO measurements will be continually collected to determine how DO and virus removal change with time in the BSF, we have a working and sound prototype that we are confident will work in BSFs in Nepal as well. Implementation of the sensors on three experimental filters in Nepal will begin in May 2014, followed by close monitoring of the three sensors to ensure correct usage before implementation of 50 sensors on household filters in the communities starting in August 2014.
Beyond the research aspect of the project, student advancement and education outreach were a big part of Phase I. Students were introduced to technical challenges that required innovative thinking and designing, and collaborating with professors and students outside of their departments. Furthermore, students gained teamwork, time management, data analysis, and presentation skills. The ability of the UIUC student team to present our work and ideas coherently and effectively to a diverse audience, from elementary school students to engineering professors to CAWST and ENPHO staff, was one of the most important skills gained throughout Phase I.
References:
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Wang, H. and Narihiro T., et al. (2014). Role of Diverse Microbial Communities in MS2 Bacteriophage Removal in Biosand Filters. Environmental Science and Technology. 2014. Under Revision.
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Shrestha, S., et al. (2011). Rotavirus and its Genotype Distribution among Children Less than Three Years Presenting with Acute Watery Diarrhoea to a General Hospital in Urban Nepal. Journal of Nepal Paediatric Society. 31(2), 110-114.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 5 publications | 1 publications in selected types | All 1 journal articles |
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Type | Citation | ||
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Wang H, Narihiro T, Straub AP, Pugh CR, Tamaki H, Moor JF, Bradley IM, Kamagata Y, Liu W-T, Nguyen TH. MS2 bacteriophage reduction and microbial communities in biosand filters. Environmental Science & Technology 2014;48(12):6702-6709. |
SU835515 (Final) |
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Supplemental Keywords:
Water treatment, monitoring, biosand filter, user habits, human healthThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.