A review on future wastewater treatment technologies: micro-nanobubbles, hybrid electro-Fenton processes, photocatalytic fuel cells, and microbial fuel cells

Abstract

The future prospect in wastewater treatment technologies mostly emphasizes processing efficiency and the economic benefits. Undeniably, the use of advanced oxidation processes (AOPs) in physical and chemical treatments has played a vital role in helping the technologies to remove the organic pollutants efficiently and reduce the energy consumption or even harvesting the electrons movements in the oxidation process to produce electrical energy. In the present paper, we reviewed several types of wastewater treatment technologies, namely micro-nanobubbles, hybrid electro-Fenton processes, photocatalytic fuel cells, and microbial fuel cell. The aims are to explore the interaction of hydroxyl radicals with pollutants using these wastewater technologies, including their removal efficiencies, optimal conditions, reactor setup, and energy generation. Despite these technologies recorded high removal efficiency of organic pollutants, the selection of the technologies is dependent on the characteristic of the wastewater and the daily production volume. Hence the review paper also provides comparisons between technologies as the guidance in technology selection.

Combination of ozone-based advanced oxidation process and nanobubbles generation toward textile wastewater recovery

“…The zeta potential in the final residence time of 300 min is reported to be −21.08 ± 0.35 mV with the corresponding distribution is depicted in Figure 6B. The negative value here is assigned to the generated ROS at the bubble interface, which leads to the bubble stability (Ushikubo et al, 2010;Selihin and Tay, 2022;Zhou et al, 2022). Typically, zeta potential value can be associated to the charge of the bubble rather than its density in the water.…”

“…The physicochemical concept of NB technology is slightly comparable to the AOP method. At a glance, NB facilitates the formation of a physical barrier such that a contaminant layers can be encapsulated by the bubble surface (Pan et al, 2021;Suvira and Zhang, 2021;Inoue et al, 2022;Selihin and Tay, 2022) thereby generating ROS efficiently (Fan et al, 2023). The formation of ROS plays a vital role in degrading organic compounds that are present in the wastewater (Mishra et al, 2017).…”

Pathways to a net-zero-carbon water sector through energy-extracting wastewater technologies

“…The main components of a PFC include a light source, cathode, photoanode, and organic wastewater as the chemical fuel. Hybridization of PFCs with nanobubbles is one of the techniques that may promise a synergistic effect in treating various types of wastewater 76 . A burr-like Ag-TiO 2 coated photoanode-based brewery effluent flow-PFC ran at 2.75 A m −2 over a 6-h period, generating a minimum voltage and power density of 0.65 V and 1.85 W m −2 , respectively 77 .…”

Hydrodynamic cavitation as an efficient water treatment method for various sewage:- A review

“…For drinking water treatment, chlorine is mainly used for disinfection treatment, but in recent years, a large number of carcinogenic disinfection by-products (DBPS) and the enhancement of drug resistance of some pathogenic bacteria limit the further development of chlorine disinfection (Gopal et al 2007). For sewage treatment, the sewage treatment methods such as Fenton method (Selihin & Tay 2022) and membrane separation method (Liang et al 2019) are difficult to balance the cost and processing efficiency. For the shortage of traditional water treatment methods, a variety of new water treatment methods have been proposed.…”