Ornamental Flowers and Fish in Indigenous Communities in Mexico: An Incentive Model for Pollution Abatement Using Constructed Wetlands

Abstract

The water crisis continues to contribute to the deterioration of both human health and natural ecosystems in many rural areas in the world. Wastewater management and poverty are part of a vicious cycle that can be broken through alternative models of community development that generate products with economic value. The Mezquital Valley in Hidalgo State in Mexico is one of the largest wastewater irrigation districts in the world. It receives part of the wastewater generated from Mexico City and the surrounding urban area. Here, an Indigenous community from the Hnahnu culture worked together with academic researchers to develop a system for wastewater treatment and reuse that uses wastewater from one of the canals that runs through the district. The wastewater passes first through a sedimentation tank and later through three levels of subsurface flow constructed wetlands that are planted with a popular ornamental flowering plant, Calla lilies (Zantedeschia aethiopica). The system removes approximately 80% of suspended solids, ammonium and coliform bacteria, and 20–30% of nutrients (i.e. orthophosphate and total nitrogen). The flowers are sold in a local market and the treated water is used in pisciculture for the production of tilapia (Oreochromis niloticus). The community has organized a business that sells approximately 1000 Calla lily flowers and approximately 300 kg of tilapia per month. This operation contributes to water pollution abatement and at the same time generates employment and economic benefits for nine individuals. This productive model could be used in other areas of the world to provide incentives for constructing and maintaining artificial wetlands for pollution abatement.