A wind-driven reverse osmosis system for aquaculture wastewater treatment, developed at the University of Hawaii at Manoa, was tested at the experimental facilities on Coconut Island, Oahu, Hawaii. With this technology, a fish tank becomes a closed aquaculture production system with zero waste discharge. The permeate (freshwater) from the system can be used as the freshwater supply for fish culture, while the brine (concentrated wastewater) can be further processed into fish feed by a duckweed-covered reactor.