This talk discusses the social-ecological dynamics of sewage using Hawaii as a case study, and presents a social-ecological framework to support decision-making for treatment and management alternatives. In Hawaii, anthropogenic nutrient pollution comes from a variety of land uses, including groundwater injection from wastewater treatment plants, and onsite septics and cesspools. Hawaii’s complex hydro-geology and oceanographic context complicates decision-makers’ ability to propose treatment solutions that are both economical and ensure the sustainability of coastal ecosystems. Hawaii is the only US state that allows cesspool construction – a concrete-lined hole that requires regular pumping, and the cheapest solution to sewage treatment. Efforts to ban cesspools have been met with fierce opposition from legislators, who cite the cost and regressive impact on poor households. Similarly, community groups successfully stopped the injection of treated wastewater from a plant into groundwater due to observed changes in coral cover. There are approximately 95,000 cesspools in Hawaii; over half of these are on the island of Hawaii, located across urban-rural environments, some in high densities, close to the water table and with little to no soil layer. Coastal communities in Hawaii represent a wide demographic spectrum differing along social, economic and cultural characteristics. These communities also rely on a diversity of coral reef ecosystem services to support their quality of life, basic livelihood, and food security.
In this presentation, we ask: (1) How do alternative wastewater technologies and management practices impact coastal water quality and coral reefs? (2) How do different Hawaiian communities value coastal ecosystems and their services? And (3) what factors affect household sewage management decisions? Drawing on existing ecological, engineering, and economic studies, we synthesize the economic, environmental, human health, and governance trade-offs associated with centralized and decentralized technologies and management options. We also summarize knowledge about how Hawaiian communities rely on reef ecosystem services. Drawing on household behavioral studies on waste, water, and energy use, we speculate about factors that could influence sewage management choices.
Results/Conclusions
We hypothesize that the ‘optimal’ treatment solution may be more complex than a simple least cost technological fix, and may differ among communities depending upon their perceptions of sewage, effect on coral reefs, and value placed on associated ecosystem services. We present a modeling and participatory approach to test this hypothesis and to better understand the interactions between social and ecological systems that control and mediate the ecological and human well-being outcomes of sewage treatment options.