July/August 2013 World Water

24 Water and Sanitation

In Mirebalais, Haiti, an innovative wastewater treatment system sets a new standard for low-cost, scalable treatment for a region with little or no infrastructure and high rates of waterborne diseases such as cholera. The newly opened Hôpital Universitaire de Mirebalais (HUM) incorporates an innovative package treatment solution provided by Butler Manufacturing Services (BMS) of Longford, Ireland, which began operation in April 2013. Its effluent quality above Caribbean standards, the facility has great potential in influencing the future of water and sanitation development throughout Haiti and the Caribbean region.

The nonprofit organization Partners In Health (PIH) built the 30-meter by 45-meter wastewater treatment system with a donation-based budget of less than US$250,000. PIH is a nonprofit organization dedicated to improving healthcare infrastructure in developing countries. The system can accommodate a flow rate of more than 300,000 liters per day of cholera-affected waste. The Mirebalais wastewater treatment facility can handle fluctuating flow rates and is scalable to grow with the needs of the hospital.

HUM is a sustainable, 18,600-square meter hospital with healthcare services that include treatment for HIV/AIDS, tuberculosis, and cholera, and treats more than 500 people per day. Like much of Haiti, the area has little or no water and sanitation infrastructure. “We knew we needed a robust water treatment system to handle HUM’s discharge,” PIH Project Manager Ann Polaneczky said, “particularly in this region because of the prevalence of water-borne diseases, such as cholera.”

Since the 2010 earthquake, Mirebalais has been home to thousands of Haitians displaced from Port-au-Prince. The region’s lack of water and sanitation infrastructure facilitated a massive outbreak of cholera. Of the more than 300,000 people affected by cholera in Haiti, 10 percent of cases have been reported in the Mirebalais region.

With the threat of cholera becoming endemic to the region, PIH looked to colleagues at The Kleinfelder Group, an engineering consultancy based in San Diego, California, USA and the nonprofit organization Engineers Without Borders USA (EWB) for help designing an affordable, effective treatment system for the new hospital.

Polaneczky drew on her relationships with fellow EWB members within Boston-based Northeastern University, and Kleinfelder, both strong EWB advocates, to develop a wastewater system that could meet the unique needs of the Mirebalais hospital. She commented, “We had

some significant constraints. We needed a system that was robust enough to handle fluctuating flow rates of more than 300,000 liters per day of cholera-affected waste. It also needed to fit into a relatively small footprint with easy operational maintenance – and we needed it all for a very small price.”

After a comprehensive review of systems that could meet HUM’s rigid design constraints, the wastewater design team opted to go with a package treatment solution from BMS. BMS Blivets are pre-fabricated package sewage treat- ment plants that can be installed in less than a day, can be operated by non-technical staff, and have low maintenance and energy requirements. The blivets have an expected effluent quality of 20-milligram-per-liter of biochemical oxygen demand (BOD) and 30-milligram-per-liter of total suspended solids (TSS).

Wastewater from the hospital is collected in a series of eight-inch PVC sewer lines and directed to a primary lift station. The lift station incorporates a basket strainer and duplex pumping system with a wetwell operational volume of 2,500 liters. The lift station sends water to one of two 19,000-liter aerated flow-equalization tanks. The Mirebalais system was designed with three blivets, but piping was installed to support additional blivets to facilitate the expansion of hospital services in the future.

The blivets provide a variety of treatment processes. The first chamber allows for primary settling and sludge storage, with flow leaving through upflow lamella plates. The second chamber contains a series of rotating, half-submerged plastic drums that provide aeration, a media surface for biomass growth, and mixing. The third chamber provides secondary settling, and another bank of upflow lamella plates. Sludge from this chamber is periodically pumped back to the first chamber.

After treatment in the blivets, the water is sent to two 3,800-liter chlorination contact tanks, where any remaining cholera or other disease agents are disinfected with calcium hypochlorite tablets. Operators are using up to 5.4 kilograms of tablets a day, with treatment completion occurring in less than 30 minutes. After chlorination, water is discharged into the nearby stream. Dechlorination capabilities were also built into the system for possible use in the future once operators gain more experience with running the system.

The wastewater treatment system is also designed to the same seismic standards as HUM. If Haiti is struck by another earthquake, as many geologists predict, the system is unlikely to have a catastrophic failure.

Breaking ground“We knew the system, if constructed properly, could exceed the expected effluent quality,” recalls Polaneczky. “We also knew that construction would be the biggest hurdle, because trained labor and construction materials are very limited in the region.”

One of the challenges that came about during construction was how to lift the blivets into place. Each blivet weighs approximately 6,000 kilograms. Polaneczky says, “Cranes are extremely rare in Haiti, and luckily one was available to take the blivets out of their shipping containers. However, we were not able to use a crane to place the Blivets in their final location.” Instead, PIH borrowed an excavator from the HUM construction site to put the blivets on their concrete pads. Construction activities occurred over a series of months.

Low-cost, scalable treatment for Haitian hospitalPartners in Health and Engineers Without Borders team up to install a low-cost wastewater treatment facility for a new hospital in Haiti. Daniel P. Saulnier, P.E., and Cecilia Carrion-Carmona explain how the scalable treatment system can be replicated for use worldwide in areas with little or no infrastructure.

STS donates sodium hypochlorite generation disinfection system

The US company Severn Trent Services (STS) partnered with the humanitarian organization Operation Blessing International (OBI) to install and commission a ClorTec® T-6 Series sodium hypochlorite generation disinfection system for the Hôpital Universitaire de Mirebalais (HUM) in Haiti.

The system is capable of producing six pounds of sodium hypochlorite per day, which can disinfect up to 625 cubic meters (165,000 gallons) of water daily for the hospital. ClorTec electrolytic technology is applicable for use in isolated locations where water purification, waste treatment or surface disinfection is required, STS Product Manager Jean-Paul Monali explained.

The 300-bed teaching hospital will provide primary care services to about 185,000 people and secondary and tertiary care to all of central Haiti and areas in and around Port-au-Prince.

OBI, which first provided humanitarian services in Haiti in 2009 at the request of Partners in Health, drilled five water wells for the new hospital. The wells included a primary hospital well and backup, an off-site well for hospital staff housing, and two community wells for public use. While the primary well was being drilled, OBI also funded construction of the hospital’s cistern and delivered several truckloads of drinking water every day for more than a month.

World Water July/August 2013

Water and Sanitation 25

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PIH educated crews about system operation during construction. “The hands-on education during construction was beneficial to everyone involved as it gave the staff an intimate understanding of the system and the opportunity to ask questions,” Polaneczky adds. PIH continues to provide training as needed.

Global applicabilitySince the wastewater system went online, other Haitian organizations have shown interest in replicating the system’s design in other cities. Polaneczky was not surprised. “The simple design really fits in with the broader Haitian goals. It is inexpensive, easy to construct and maintain, and doesn’t require much energy. It is a great system for areas with little to no infrastructure,” she explains.

PIH contends that the design could be replicated for projects worldwide in regions without clean water and sanitation. Other hospital owners and project teams in Haiti have contacted PIH to discuss the design.

Polaneczky concludes, “This project proves that a wastewater system doesn’t have to be complex or extremely costly to bring high water quality standards to areas with little or no supporting infrastructure. The Mirebalais project is certainly proof that with a little creative thinking, we can bring safe, clean water to everyone who needs it – in Haiti and beyond.”

Authors’ NoteDaniel P. Saulnier, P.E., is the coordinator of the Civil & Environmental Engineering Co-op Program and faculty advisor for Engineers

Without Borders, both positions located at Northeastern University, near Boston, Massachusetts, USA. He can be reached by email at d.saulnier@neu.edu. Cecilia Carrion-Carmona is a project professional for Kleinfelder, a global science, engineering and architecture consulting firm. She can be reached by email at ccarmona@kleinfelder.com. Dan and Cecilia volunteered their time and expertise to complete the design of the Mirebalais wastewater treatment system.

Above left: PIH Project Manager Ann Polaneczky examines the blivet-based wastewater treatment system located at the Mirebalais hospital. Above right: Mirebalais hospital wastewater treatment system relies on three prefabricated blivets to process sewage.

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