Small water supply system with plasma-modified poly(tetrafluoroethylene) membrane for drinking water production

Abstract

The small water supply systems aim at supplying safe drinking water to small communities in remote areas. This study applies an automatic small water supply system comprising 20 plasma-grafted poly(tetrafluoroethylene) (PTFE) membranes with a 1.42 m2 filtration area to generate permeate at a capacity of 3 m3/day from raw water collected from a local river. The system was tested by 34 days in phase I with bubble scraping and by 120 days in phase II without bubbling, with water quality, cross-membrane pressure drops, and dissolved organic carbons’ and foulants’ characteristics being recorded. Even with typhoon water turbidity up to 1714 nephelometric turbidity units (NTU), the system yields drinking water, meeting Taiwan’s standards. The system is fully automatic with no coagulant or disinfectant doses; an operational cost of 0.21 USD/m3 is proposed, much lower than the tariffs applied in most countries. The foulant characteristics and washing efficiencies noted are discussed.