| Abstract |
With increasing types of micropollutants detected in water environments, especially the discovery of a considerable number of emerging micropollutants with major potential harms to aquatic ecosystems and human health, the treatment and remediation of micro-polluted complex water has gradually become a global challenging environmental problem, which needs to be solved by emerging green and low-carbon technologies. However, the end product from micro-polluted complex water treated by advanced oxidation and other traditional technologies is CO2, undoubtedly becoming an approach against the concept of carbon neutrality. The realization of carbon neutrality in the process of treating micropollutants in complex water requires to break away from the existing mindset of water treatment and remediation, and fully open up the mode of overall technological innovation. This review first defines the new concept of "complex water", which refers to a series of waters with complex characteristics or containing multi-components, such as complex waters in mining areas, urban runoff, farmland drainage or agricultural runoff and oil-containing waters, and even involving multicomponent polluted rivers, stream, lakes, seawater and groundwater; according to this definition, some examples of typical complex water are illustrated. Then, the micro-pollution phenomena (refers to potential harms on ecosystems and human health resulted from harmful substances with low concentration levels in waters) and the main types (including microplastics and pharmaceuticals and personal care products such as antibiotics, anti-inflammatory and analgesic drugs, beta receptor antagonists, psychotropic drugs, hypolipidemic drugs, as well as cosmetics and skincare products used in daily life) of emerging micro-pollutants that occur in waters (including complex water) are systematically combed and summarized. Afterwards, the latest progress of some advanced treatment/remediation methods including physico-chemical technology such as activated carbon adsorption, membrane treatment and ultrasonic treatment, advanced oxidation technology such as ozone catalytic oxidation, photocatalytic oxidation, electrochemical oxidation, persulfate oxidation, as well as Fenton, photo-Fenton, and electro-Fenton catalytic oxidation, biological treatment technology such as biofilm and activated sludge, and combined or collaborative treatment technology of physicochemical technology, advanced oxidation and biological treatment technology for micro-polluted complex water is comprehensively introduced and discussed. In particular, the strategy and solution for the treatment and remediation of micro-polluted complex water based on the carbon-neutral approach is tentatively proposed, including (1) model of pure technological innovation, based on innovative physiochemical treatment technologies, advanced oxidation, biological treatment technologies, and their combined/ collaborative treatment technologies, with the emphasis on zero carbon emissions; (2) model dominated by changing microbial functions (i.e. by capturing greenhouse gases) and by increasing the photosynthetic potential of green plants; (3) model of advanced treatment technologies coupled with ecological enhancement of existing carbon sinks; and (4) model of comprehensive utilization based on ecological remediation. Thus, the future path in treatment and remediation of micro-polluted complex water should be created from the perspective of the overall technological innovation with multiple goals under the framework of carbon neutrality. Finally, the future research focus and development direction of this field are outlined, aiming at promotion of the systematic research and eradication of water micro-pollution problems, thus laying a scientific foundation for improving aquatic ecosystems, enhancing the safety of drinking water and realizing the goal of carbon neutrality. |
