Water Resources Research Act Program

Details for Project ID 2017HI475B

Wastewater treatment for point source processing and resuse

Institute: Hawaii
Year Established: 2017 Start Date: 2017-03-01 End Date: 2018-02-28
Total Federal Funds: $14,093 Total Non-Federal Funds: $28,197

Principal Investigators: Michael Cooney

Project Summary: Water limited “island” communities such as those in Hawaii face mounting demands on water supply such as increased consumption, lower rainfalls, decreased ground recharge, and redirection of rainfalls over natural watersheds - all of which stress pre-existing ground supply of potable water. Of the many options in Hawaii – e.g., conservation, watershed repair, rainwater capture - the most obvious but least employed is the recycle of treated wastewater. This is both unfortunate and unwise; approximately 100 million gallons per day of water pass through Hawaii’s wastewater treatment plants prior to its discharge into the ocean. There are also at least 100,000 cesspools in Hawaii, most if not all of which are designed to discharge its water without reuse. Given Hawaii’s year round sunshine, land limitations, growing population, and isolation from mainland markets, an attractive use of recycle water in Hawaii is to grow edible/energy crops using high-density hydro/aeroponic technologies in greenhouse “malls”. The cost of producing recycled R1 water is not the only detriment to its commercial use. The main technologies used to produce R1 water – e.g. aerated activated sludge beds and membrane reactors – remove micro and macronutrients through the production of biomass or filtration. This diminishes the value of the treated water as a resource to irrigate food or energy crops. The cost of producing R2 water, by contrast, is lower and tends to retain plant available macronutrients. As such, the production of R2 water (in lieu of R1) and its recycle for irrigation of edible, energy, or horticulture crops makes it an attractive alternative. With this work we seek to establish a foundational long-term research program researching the sustainable recycle of R2 wastewater for cultivation of edible/energy crops in aeroponic growth systems. In application we seek to ultimately produce a peer reviewed body of research on crop feasibility and value to Hawaii, pathogen control protocols, and the steps necessary to transition the work to field scale application including the recycle of wastewater treatment plant wastewater for the production of food and energy crops in controlled aeroponic greenhouses.