title: Emerging contaminant degradation and removal in algal wastewater treatment ponds: Identifying the research gaps.
abstract: Whereas the fate of emerging contaminants (ECs) during 'conventional' and 'advanced' wastewater treatment (WWT) has been intensively studied, little research has been conducted on the algal WWT ponds commonly used in provincial areas. The long retention times and large surface areas exposed to light potentially allow more opportunities for EC removal to occur, but experimental evidence is lacking to enable definite predictions about EC fate across different algal WWT systems. This study reviews the mechanisms of EC hydrolysis, sorption, biodegradation, and photodegradation, applying available knowledge to the case of algal WWT. From this basis the review identifies three main areas that need more research due to the unique environmental and ecological conditions occurring in algal WWT ponds: i) the effect of diurnally fluctuating pH and dissolved oxygen upon removal mechanisms; ii) the influence of algae and algal biomass on biodegradation and sorption under relevant conditions; and iii) the significance of EC photodegradation in the presence of dissolved and suspended materials. Because of the high concentration of dissolved organics typically found in algal WWT ponds, most EC photodegradation likely occurs via indirect mechanisms rather than direct photolysis in these systems.
authors.affiliation: School of Engineering and Advanced Technology, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
authors.forename: Zane N
authors.initials: ZN
authors.lastname: Norvill
authors.affiliation: School of Engineering and Advanced Technology, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand.
authors.forename: Andy
authors.initials: A
authors.lastname: Shilton
authors.affiliation: School of Engineering and Advanced Technology, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand. Electronic address: B.J.Guieysse@massey.ac.nz.
authors.forename: Benoit
authors.initials: B
authors.lastname: Guieysse
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D058086:Microalgae / Q000378:metabolism*; D010782:Photolysis; D061005:Ponds; D014865:Waste Disposal, Fluid; D062065:Wastewater / Q000737:chemistry*
chemical_list: D062065:Wastewater
keywords: Algae; Antibiotic; Emerging pollutant; Estrogen; HRAP; Pharmaceutical