Ecologically Engineering and Wastewater Treatment Wetland Alternatives for Utila, Bay Islands, Honduras

Virginia Collins and Dr. Ted Endreny. ERE 596: Ecological Engineering in the Tropics. SUNY College of Environmental Science and Forestry, Syracuse, NY 13210

The impetus for environmental change in the twentieth century is often the result of near-crisis conditions before action is actually taken. Ecological engineering utilizes the functions readily available in nature to benefit a human problem. Utila Island, a haven for travelers and divers, a tropical get-away, is part of the Bay Island system of Honduras, Central America. The waste of Utila Island is currently mismanaged, and pumped directly into the ocean with minimal treatment. Although an ecological crisis is not necessarily eminent, this mismanagement violates ecological engineering principles. Ecological engineering principles of this project include the output rule, stating that all waste emissions from a project should be within the assimilative capacity of the local environment, the acid test, as this design project is a test of the accuracy of ecological theory, and finally, self sustaining and self design nature of the design. The designed alternative wastewater treatment method for the island is a constructed wetland, which accomplishes treatment through a complex combination of physical, chemical and biological mechanisms. The design consists of three parts - a primary settling tank, a constructed wetland, and a land application field. Based on a population of roughly 3000 people, the constructed wetland will be approximately 2.2 hectares in area, 220 meters long by 100 meters wide, approximately 1 meter deep, with a slope of 0.1%. The wetland will be lined with clay, and seeded with natural hydrophilic plants, such as cattail (Typha), Common reed (Phragmites), bulrush (Scirpus) and duckweed (Lemna). The waste will be pumped to the constructed wetland via solar energy. The constructed treatment wetland will also supplement habitat for local wildlife and endangered species (Ctenosaura bakeri), recharge groundwater, and be a source of supplies (mangrove wood) for local artisans.

CONCEPTUAL DESIGN FOR A WASTEWATER TREATMENT WETLAND FOR UTILA, HONDURAS

Gwen Kernan & Dr. T. Endreny. ERE 496 Ecological Engineering in the Tropics Course, 207 Marshall Hall, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210

Utila is a small, tropical island off of the Honduran coast. There is no established wastewater plan on the island. Sewage from the population runs directly into the Caribbean Sea which surrounds the island. The sewage is a source of pollution and currently is polluting the Sea. Even pollution is present; the water of the Caribbean Sea that surrounds Utila does not appear to be contaminated by the naked eye. The water does in fact have fecal coliform pollution. This shows that the buffer capacity is negatively affected by the lack of wastewater treatment. The buffer capacity is closely related to the ecological stability of the environment. The waste of Utila needs to be used to push the island toward sustainability. The wastewater will be pumped to the wetland where it will be treated. The grey water will be separated from the black water. The grey water will be infiltrated back to the water table through bioretention. Should some waste products fail to be treated by the wetland, alternative treatment systems will be investigated using adaptive techniques. The wetland will work to continually recharge the freshwater of the island and protect the buffer surrounding the island.