Full-Scale Floating Treatment Wetlands in Pakistan: From Performance Evaluation to Public Acceptance

Abstract

Many communities in Pakistan use unsafe water polluted by domestic or industrial activities. Water treatment infrastructure is hardly in place, while the country's socioeconomics jeopardizes its maintenance and improvement. Especially in rural areas, any cost-effective and passive solution to improve water quality is a boon. Here we present the successful application of a full-scale floating treatment wetland (FTW) for attenuating the pollutant concentration in a crude oil wastewater pit. Floating rafts, covering about 1/3 of the pit's water surface area (10,000 m2), were established using indigenous wetland plants. Successful removal of organics (>97%), hydrocarbons (99.6%), total dissolved solids (82%), heavy metals, and toxicity was recorded within six-months. Mass balance confirmed removal of organics up to 2.63 x 105, whereas carbon sequestration by FTW was 2.11 x 103 kg. About 500,000 m3 of wastewater received treatment at a cost of US$0.0184 per m3, which was later reduced to US$0.0033 per m3. A cross-sectional survey illuminated that application of the FTW positively impacted the lives of local communities. The FTW also became a new habitat for native bird species, thus underscoring the improved water quality and highlighting the study's alignment with the United Nations Environment Program for better conditions for water supply and biodiversity.