Efficacy of Juncus maritimus floating treatment saltmarsh as anti-contamination barrier for saltwater aquaculture pollution control

Abstract

Floating treatment saltmarsh (FTS) is a new concept proposed to name floating treatment wetlands made of estuarine halophytes especially engineered for the control of contamination in brackish and saline waterbodies. The first full-scale FTS was implemented in 2018 to create an anti-contamination barrier for saline aquaculture wastewater treatment in an estuarine tidal lagoon. Results of a two-year investigation validated ‘Phytobatea’ modular technology for floating wetlands implementation and operation. Juncus maritimus crossflow FTS efficiency on main mariculture wastewater constituents' removal under low hydraulic retention time was remarkable, i.e., total phosphorus (86%), total suspended solids (82%), biochemical oxygen demand (78%), total organic carbon (55%), turbidity (53%), Escherichia coli (30%), and dissolved oxygen increased (19%). Key features of the native halophyte Juncus maritimus were determined to ensure 75–100% survival under high water salinities up to 38 g/L. A scientific literature review confirmed strategic sectors' growing interest in Juncus maritimus as raw material, supporting its possible cultivation as an added-value by-product within integrated aquaculture systems. Plants' root systems colonization by crabs, shrimps, and young individuals of the critically endangered European eel (Anguilla anguilla), revealed the role of FTS for biodiversity conservation, and its potential as functional habitat, nursery, and refuge for aquatic fauna species in contaminated waterbodies. HIGHLIGHTS Floating treatment saltmarsh (FTS) concept is firstly proposed to define saline FTWs of halophytes.; The initial size of the plants strongly determines J. maritimus survival in saline contaminated waterbodies.; Crossflow FTS are efficient solutions for mariculture wastewater treatment under high salinities and low hydraulic retention times.; The growing interest in halophytes and their by-products supports FTS implementation within integrated aquaculture systems.; FTS can play a strategic role as artificial habitats for biodiversity conservation and enhancement.;

Keywords

• anti-contamination barrier
• constructed wetlands
• floating treatment saltmarshes
• halophytes
• juncus maritimus
• saline aquaculture wastewater