Impact/Purpose:

Socorro is located in the Bocacosta region along the volcanic slopes of the highlands in southwestern Guatemala. Despite the village’s proximity to a major international highway, infrastructure is severely underdeveloped. A survey of the village reveals that few have latrines or other waste disposal systems, and in most cases the waste is channeled towards the Chichoy River. This river also serves as a drinking water source for approximately 75% of the village. Due to community effort, most homes now have piped untreated river water, which is used for drinking, cooking, and washing. However, this water is not potable. Water- and soil-borne pathogens cause problems such as scabies, lice, diarrhea, dysentery, hepatitis A, giardia, shigella, entamoeba, and soil transmitted helminthes. We hope to alleviate these health issues by implementing a slow sand filtration (SSF) system that will use iron oxide particles mixed in with the sand substrate.

Description:

Long-Term Removal in Columns

To simulate the normal operation of a biosand filter, 4 glass columns (Figure 1) packed with different iron orientations were charged daily with 1 PV of aquifer water containing ~10⁸ pfu/mL of MS-2 bacteriophage, a commonly used surrogate for enteric virus, and 2.5% pasteurized primary effluent (PE). While the sand column averaged only 1-log₁₀ (90%) removal, all three iron columns had greater than 5-log₁₀ (99.999%) removal for the duration of the experiment.

M2-2 Removal by BSFs

Plastic biosand filters were used to study virus removal by BSFs amended with iron nails. The nail filter started with a 6.5-log₁₀ removal (99.99997%) but retention of virus particles quickly declined as flow paths short-circuited the iron. These independent flow paths were caused by the difference in size and shape between the nails and sand media. To avoid this problem, two concrete biosand filters were constructed using a steel mold built to specifications provided by CAWST. The filters were packed and charged daily with commercially available iron particles. The sand filter achieved an average of only about 2-log₁₀ (90%) removal (Figure 2), while the iron particle filter maintained an average of 6-log₁₀ (99.9999%) reduction of viriron particles. The iron particles had dimensions similar to the sand and, thus, promoted near plug-flow conditions that allowed for sufficient contact time between each filter charge.

Testing for Locally Available Iron Materials

It is highly desirable to pack the filters with iron that is readily obtained in rural Guatemala. Four plastic bottles, shown in Figure 3, packed with different iron sources were charged with 1 PV aquifer water and ~10⁸ pfu/ml MS-2. The bottles were run for a period of 2 weeks. Nails achieved an average of only 3-log₁₀ removal, which continued to decline over the course of the experiment. Zerovalent iron particles obtained an average removal of approximately 7-log₁₀ and steel wool an average removal of 5.5-log₁₀ (Figure 3). The large surface area of zerovalent iron particles and steel wool facilitated higher removal.

URLs/Downloads:

Final Progress Report

2010 Progress Report

Record Details:

Record Type:PROJECT( ABSTRACT )

Start Date:08/15/2009

Completion Date:08/14/2010

Record ID: 249508

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Related Organizations:

Role :OWNER

Organization Name :UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN

Mailing Address :601 E John St

Citation :Champaign

State :IL

Zip Code :61820

Project Information:

Approach :

Slow sand filters have been empirically proven to effectively remove bacterial pathogens from water, resulting in a filtrate of potable quality. However, slow sand filters are often not effective against viruses for several reasons: viruses are too small to be subject to the mechanical filtration of the slow sand filter, they are electrostatically repelled by most sand particles, and they are usually not metabolized by organisms that grow in the biologically active layer of the SSF. Thus, a form of virus removal is often required to treat water that has been through a slow sand filter. The disinfection technique most prevalently applied in developing areas is chlorine, due to its ease of use. However, chlorination is often difficult to implement because of training requirements to properly store, handle, and apply chlorine. Also, the harmful effects of its disinfection by-products make its implementation ethically questionable when alternatives are available. The new technology that is being investigated is the use of iron oxides to enhance virus removal. Iron oxide has been shown to effectively remove viruses from water.

Cost :$10,000.00

Research Component :Pollution Prevention/Sustainable Development

Approach :

Slow sand filters have been empirically proven to effectively remove bacterial pathogens from water, resulting in a filtrate of potable quality. However, slow sand filters are often not effective against viruses for several reasons: viruses are too small to be subject to the mechanical filtration of the slow sand filter, they are electrostatically repelled by most sand particles, and they are usually not metabolized by organisms that grow in the biologically active layer of the SSF. Thus, a form of virus removal is often required to treat water that has been through a slow sand filter. The disinfection technique most prevalently applied in developing areas is chlorine, due to its ease of use. However, chlorination is often difficult to implement because of training requirements to properly store, handle, and apply chlorine. Also, the harmful effects of its disinfection by-products make its implementation ethically questionable when alternatives are available. The new technology that is being investigated is the use of iron oxides to enhance virus removal. Iron oxide has been shown to effectively remove viruses from water.

Cost :$10,000.00

Research Component :P3 Challenge Area - Water

Approach :

Slow sand filters have been empirically proven to effectively remove bacterial pathogens from water, resulting in a filtrate of potable quality. However, slow sand filters are often not effective against viruses for several reasons: viruses are too small to be subject to the mechanical filtration of the slow sand filter, they are electrostatically repelled by most sand particles, and they are usually not metabolized by organisms that grow in the biologically active layer of the SSF. Thus, a form of virus removal is often required to treat water that has been through a slow sand filter. The disinfection technique most prevalently applied in developing areas is chlorine, due to its ease of use. However, chlorination is often difficult to implement because of training requirements to properly store, handle, and apply chlorine. Also, the harmful effects of its disinfection by-products make its implementation ethically questionable when alternatives are available. The new technology that is being investigated is the use of iron oxides to enhance virus removal. Iron oxide has been shown to effectively remove viruses from water.

Cost :$10,000.00

Research Component :P3 Challenge Area - Pollution Prevention

Approach :

Slow sand filters have been empirically proven to effectively remove bacterial pathogens from water, resulting in a filtrate of potable quality. However, slow sand filters are often not effective against viruses for several reasons: viruses are too small to be subject to the mechanical filtration of the slow sand filter, they are electrostatically repelled by most sand particles, and they are usually not metabolized by organisms that grow in the biologically active layer of the SSF. Thus, a form of virus removal is often required to treat water that has been through a slow sand filter. The disinfection technique most prevalently applied in developing areas is chlorine, due to its ease of use. However, chlorination is often difficult to implement because of training requirements to properly store, handle, and apply chlorine. Also, the harmful effects of its disinfection by-products make its implementation ethically questionable when alternatives are available. The new technology that is being investigated is the use of iron oxides to enhance virus removal. Iron oxide has been shown to effectively remove viruses from water.

Cost :$10,000.00

Research Component :P3 Challenge Area - Materials & Chemistry

Project IDs:

ID Code :SU834296

Project type :EPA Grant