title: Removal efficiency of a constructed wetland combined with ultrasound and UV devices for wastewater reuse in agriculture.
abstract: This study evaluates the treatment efficiency of a chemical-free water treatment for treating the secondary effluent of a municipal wastewater treatment plant with the aim of reusing the water for agriculture. Urban wastewater was treated by three units run in series: a full-scale horizontal sub-surface flow constructed wetland, a small pond with an ultrasound (US) system and a UV device. The treatment efficiency was evaluated in terms of the Italian wastewater limits for irrigation reuse, water quality improvement (removal percentage) and algae bloom control. The tolerable infection risk, associated with the use of wastewaters for irrigating crops, was also assessed by applying the microbial risk analyses proposed in the WHO guidelines for wastewater reuse. The constructed wetland was efficient in reducing physical-chemical and microbiological concentrations, and its efficiency was very steady over the investigation period. The UV system significantly improved water quality (p<0.05) in terms of pathogen concentration with a further average decrease from 0.35 to 1.23 log units, depending on the microbiological parameter. The US device was able to prevent algae bloom on a free water surface and maintain Chlorophyll-a concentration stable and low 2 months after activation.
authors.affiliation: Department of Agri-food and Environmental Systems Management, University of Catania, Catania, Italy. attilio.toscano@unict.it
authors.forename: Attilio
authors.initials: A
authors.lastname: Toscano
authors.affiliation: School of Biological Sciences, Portsmouth University, Portsmouth, UK.
authors.forename: Claire
authors.initials: C
authors.lastname: Hellio
authors.affiliation: Department of Agri-food and Environmental Systems Management, University of Catania, Catania, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Marzo
authors.affiliation: Department of Agri-food and Environmental Systems Management, University of Catania, Catania, Italy.
authors.forename: Mirco
authors.initials: M
authors.lastname: Milani
authors.affiliation: School of Biological Sciences, Portsmouth University, Portsmouth, UK.
authors.forename: Karen
authors.initials: K
authors.lastname: Lebret
authors.affiliation: Department of Agri-food and Environmental Systems Management, University of Catania, Catania, Italy.
authors.forename: Giuseppe L
authors.initials: GL
authors.lastname: Cirelli
authors.affiliation: Institute for Sanitary Engineering and Water Pollution Control, University of Natural Resources and Life Sciences, Vienna, Austria.
authors.forename: Günter
authors.initials: G
authors.lastname: Langergraber
mesh_terms: D000383:Agriculture; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D005068:Eutrophication; D058086:Microalgae / Q000737:chemistry; D059027:Recycling / Q000379:methods*; D012802:Sicily; D014465:Ultrasonics; D014466:Ultraviolet Rays; D062065:Wastewater; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*; D053833:Wetlands
chemical_list: D002734:Chlorophyll; D000077194:Chlorophyll A; D062065:Wastewater