The new insight about electrode interface behaviour via in situ ultrasound three-dimensional representation monitoring based on a bio-electrochemical system

In situ assessment of the initial phase of wastewater biofilm formation: Effect of the presence of algae in an aerobic bacterial biofilm system

The initial start-up attachment stage that dominates biofilm formation is an unstable process and is time-consuming. In the present study, Chlorella sp. was introduced into a general aerobic biofilm system to explore whether the addition of algae improved the initial attachment phase of biofilm. Compared with those of the bacterial biofilms, the initial algal-bacterial biofilms were more stable and had a thicker, denser, and rougher surface. Further investigation suggested that the concentration of extracellular polymeric substances (EPSs) in the algal-bacterial biofilm was 31.33 % greater than that in the bacterial biofilm. Additionally, the algal-bacterial flocs had greater free energies of absolute cohesion (ΔGcoh) and adhesion energy (∆Gadh) than did the bacterial flocs. These phenomena contribute to the speediness and stabilization of initial algal-bacterial start-up biofilms. Specifically, algae inoculation increased microbial community diversity and promoted the growth of bacterial members related to biofilm development. In conclusion, both physicochemical interactions and biological processes strongly influence microbial attachment during the initial biofilm formation process and further promote strengthening.

Electrochemical methods for landfill leachate treatment: A review on electrocoagulation and electrooxidation

Landfill leachate is a kind of difficult-to-degrade wastewater with complex water qualities. Waste filtrate cannot be thoroughly treated by traditional biological, physical and chemical methods. In the past five years, electrochemical methods have attracted widespread attention in the treatment of landfill leachate. The article pointed out that for the colloidal/suspended particles in the landfill leachate, using of electrocoagulation can achieve a good treatment effect. Aiming at the characteristics of the dissolved organic matter in the landfill leachate and the high concentration of chloride ions, a more efficient removal can be available by using of electrooxidation. In this review, the latest achievements and basic principles of electrocoagulation and electrooxidation have been introduced. Meanwhile, the influence of different process parameters on these two electrochemical methods was summarized. It also reviewed the effect of electrochemical technology as an independent system or combined with biological and physical chemical processes on the treatment of landfill leachate, as well as the cost of various laboratory scales. Finally, several main problems and challenges encountered by electrochemical methods were briefly discussed, and the prospects for new development and future research were also provided.

The characteristic of electrode of degradation of bio-electrochemical system based on in-situ ultrasonic monitoring: Biofilm and ion precipitation

Electrode interface behavior is a decisive factor affecting the performance of bio-electrochemical systems, and traditional monitoring methods cannot provide real-time feedback. Therefore, in situ ultrasonic monitoring was performed to continuously monitor the formation process of electroactive biofilm and salt precipitation on the cathode surface. The results showed that biofilm was attached to the cathode surface first. Then, Ca²⁺ and Mg²⁺ precipitation gradually invaded the biofilm and accumulated between the cathode and the biofilm. The electrochemical performance of the biofilm adhesion and initial ion invasion process was improved. However, the electrochemical performance of the precipitation layer was decreased, while the operation time increases. In this paper, based on the air cathode scaling analyzing a new method for monitoring the electrode interface of bio-electrochemical system was provided, and the performance was recovered by using reverse electric field.