Taking on Challenges, growing from the experience
The University of Missouri Engineers Without Borders (EWB) chapter completed their second assessment trip to rehabilitate a wastewater treatment facility in Ciudad España, Honduras, during MU’s spring break. The team of six students and their professional mentor, Nicole Young of CDM, spent their time working to assess the condition of the facility after a new city water board team removed water hyacinths that had been in place during the last assessment trip in May 2010.
“We didn’t recommend the removal of the water hyacinths and had to change our approach because the water levels were lowered,” Steven Stepanovic, a junior civil engineering student, said.
The wastewater system used the floating aquatic plants for nutrient removal, but members of a new water board decided to remove them because they saw the lagoon was not functioning properly and did not realize the feature could be modified.
“Our original goal was to spend the trip testing the water quality and performance of the facility without the hyacinths, but was then changed to reinforcing communication with the community, observation and gauging the depth of the sludge,” Danny Nabelek, a junior in electrical and computer engineering, said.
The first few days of the trip were spent meeting with the newly elected water board leaders and communicating EWB’s role in the process, as well as working with their budget to determine how they could contribute financially to the project.
“We presented a formalized document outlining our observations, immediate recommendations, long-term recommendations and defined the community’s role. They committed to pay 50 percent of six months of water sampling costs,” Stepanovic said.
The team also made observations and recommendations regarding the safety and health issues with facility operators.
A hefty amount of their time was spent conversing with the plant operator, allowing him to ask questions and better understand the reasons for certain changes in the lagoon system.
The lagoon system was originally designed as a three-cell lagoon-type wastewater treatment plant, in which biological plants use microorganisms to treat the wastewater naturally under controlled conditions. This system’s third cell was designed as a maturation cell with a replaceable filter that requires maintenance and changing every five years. A lack of instruction and guidance resulted in improper filter replacement causing the third cell to malfunction.
“The community dug a channel in the third cell bypassing the entire cell and its filter, sending water straight to the effluent. Bypassing the third cell in this way could allow the unused part of the cell to have too much plant growth and change the entire cell,” Stepanovic said.
The lagoon-type system begins with a chamber with multiple grit screens. These screens start large and get progressively smaller to catch all the non-organics in the water. Grit chambers must be periodically cleaned out. From the grit-screening chamber, water flows into the first cell. The first and second cells allow organics to settle while biological processes, anaerobic and aerobic, further treat the water. The second cell also includes baffling to increase the retention time of that cell. The final cell was designed as a maturation cell or a “polishing cell,” which further treats the water by passing it through a filter.
The team’s next steps will involve about six months of water quality sampling to determine whether or not to change the third cell, as well as post-assessment documentation and an examination of flow rates to determine the best way to maintain the system.
They plan to draft an operations and maintenance manual by December, after determining the best design.
“They don’t have a document that is easy to understand, with basic maintenance and safety information,” Nabalek said.
Nabalek and Stepanovic said without private donations, contributions from the College of Engineering, and the Organization Resource Group at Mizzou they received, the project would not have been possible.
Paul Roth, a retired 1956 civil engineering alumnus and a member of the MU Civil Engineering Academy, generously contributed $9,500 to the group’s effort.
“Water management is perhaps the most essential of all elements for health in the world,” Roth said. “This project is a great opportunity to help a community in a disadvantaged country, while giving Mizzou engineering students experience they might not get in any other way. Giving help to others who need assistance is who we are as a nation.”
Stepanovic will be president of EWB Mizzou in the fall, and Nabalek will serve as vice president of communications.
“We hope to take on more projects with more members in the next year,” Stepanovic said.
“It’s so fascinating to watch an international project where you as a student actively work as an engineer across cultures,” Nabalek said.