Grantee Research Project Results
Final Report: Sustainable Sanitation Strategies for Peri-Urban and Rural Developing Communities
EPA Grant Number: SU835525Title: Sustainable Sanitation Strategies for Peri-Urban and Rural Developing Communities
Investigators: Oyanedel-Craver, Vinka , Parola, Alessandro , Damicis, Jessica , Rosales, Jonathan , Rocchio, Joseph , Briones, Maria , Gorga, Mattia
Institution: University of Rhode Island
EPA Project Officer: Packard, Benjamin H
Phase: I
Project Period: August 15, 2013 through August 14, 2014
Project Amount: $14,805
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 - Sustainable and Healthy Communities , P3 Challenge Area - Safe and Sustainable Water Resources , P3 Awards , Sustainable and Healthy Communities
Objective:
The URI chapter of Engineers for a Sustainable World (ESW-URI) has been continuously working at the Seeds of Wisdom School (San Mateo Ixtatan, Guatemala) since 2009 to provide sustainable sanitation solutions that will reduce pollution levels in the affected region and advocate for managing the wastewater pollution in other Guatemalan communities. In 2012, the ESW-URI team built a septic tank for Seeds of Wisdom School. This septic tank was the first ever installed in the community. The installation of this unit was crucial to the project because it is the first step for the sanitation train of treatment, in which solids are settled prior to further treatment. In 2013 the ESW-URI team went again to San Mateo to assess the performance of the septic tank and to perform educational activities such as teaching the students at the Seeds of Wisdom School about hand pump systems and other technologies that ESW-URI is planning to implement as secondary treatment.
The overall goal of ESW-URI's project is to minimize the contaminant emission discharged to the environment and to recovery nutrient and organic matter from wastewater streams. Wastewater treatment is not a traditional customs for the Guatemalan community, making this project a cultural challenge to be overtaken, but nevertheless the community will be presented with positive results from our project.
Currently the task at hand is to implement a sustainable secondary treatment to further reduce the impact of the school’s wastewater on the environment. The proposed treatment system for Seeds of Wisdom is to install two different types of secondary wastewater treatment systems. The secondary treatment options would be a single pass sand filter and a vegetated wetland system. These two systems will also serve to show and teach other member of the community about the benefit of wastewater treatment. The wastewater line would run along the outside of the school building and discharge to dosing siphon chambers which would regulate the wastewater discharge for both systems. Both the sand filter and wetland will treat half of the primary stream. The effluent for both secondary systems will be conditioned for irrigation of crop located around the school.
Various sand filter types and designs have been extensively tested and used in the United States. Treatment mechanisms in a sand filter include physical filtering of solids, ion exchange (alteration of compounds by binding and releasing their components), and biodegradation of organic contaminant by microorganism. A properly operated sand filter should produce high-quality effluent with less than 10 mg/liter BOD, less than 10 mg/liter TSS, and less than 200 cfu/100 ml fecal coliform bacteria, an indicator of viruses and pathogens.
Constructed wetlands (CW) have been also selected because they mimic the properties of natural wetlands. They are used in many developing countries as a primary or secondary treatment method for wastewater due to their relatively low cost compared to other methods of pollution control. A CW enables the filtration, settling, and bacterial biodegradation of the pollutants contained in the wastewater. Plants translocate the oxygen from the atmosphere and bring it through their roots to mix with the saturated media. This process creates an aerobic environment that promotes the development of a diverse population of bacteria and rhizobacteria. These organisms metabolize the organic matter and reduce the pathogenic load in the wastewater. ESW-URI is working with an agricultural science teacher at the Seeds of Wisdom school to select native Guatemalan plant species to be used in the CW.
CWs are effective in removing organic matter, however nutrients are only partially treated in these systems. The next step in our treatment process will be the use of drip irrigation systems to recover these nutrients from the treated wastewater. Considering that the community’s main food resource is corn, and that almost every property in town has a cornfield, using these nutrients as plant fertilizer will be an economic benefit as well as an environmental benefit.
These systems will be installed during the summer 2014 and will be maintained by the students enrolled in the Seeds of Wisdom School. The students will also help to raise awareness about the negative impact of poor sanitation on the societal, economic and environmental resources of the San Mateo Ixtatan community. They will also gain technical knowledge, which will ensure the proper operation and maintenance of the system. The involvement of organization such as the Ixtatan Foundation and local authorities since the design stages of this project has helped to develop the sense of ownership of the system, which is essential to ensure the successful operation and replication of this system in other locations around the town and hopefully in nearby villages.
To maintain the septic tank in proper working order it has been determined that the tank will eventually require the removal and treatment of biosolids. ESW-URI determined that an on- site treatment provided the best option for a safe and effective treatment. The alternative treatment considered is the vermicomposting of the biosolids from the septic tank. Vermicomposting is the process of using earthworms (Eisenea foetida) to break down organic wastes and reduce the pathogenic load into a form that can safely be used as a fertilizer in the local farming activity. As the worms population increases the new worms can be used as source for new vermicomposting systems as well as another by-product such as animal feed.
Conclusions:
The final product of the ESW-URI project is to have a zero emission wastewater treatment system and reusable water for agricultural purposes. The products produced by the systems would provide an alternative method for fertilizing there crops, which in return would have a positive impact on the environment of San Mateo Ixtatan. The educational purpose of this project is to demonstrate to the Guatemalan community how local materials can be utilized to decrease the amount of pollution. This sanitation system should serve as an example for other communities to imitate and duplicate. These modules will help the students attain a thorough understanding of the entire treatment system and hopefully inspire a greater interest in engineering education in general.
Supplemental Keywords:
Sustainability, Wastewater Treatment, Constructed Wetlands, Sand Filter, Septic Tank, Dosing Siphon, Guatemala, Water Quality.The 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.