# Micro-Nanobubble Technology in Surface Cleaning and Defouling
## 4 Biofouling Mitigation and Advanced Cleaning Technologies
### Advancements in Water and Wastewater Treatment  
By improving contaminant removal, biofilm disruption, and system efficiency, NB technology has completely changed the treatment of water and wastewater [12]. NBs facilitate efficient oxidative processes by producing ROS and enhancing oxygen transport, thereby reducing the need for hazardous chemical oxidants [1]. This makes them ideal for disinfecting water contaminated by pathogens, controlling biofouling in irrigation systems, and enhancing the structure of microbial aggregates for effective treatment. Owing to their unique properties, including high internal pressure and confined shear stresses, NBs are also suitable for cleaning surfaces. They make it easier for cleaning solutions to enter cracks by breaking up biofilms, removing impurities, and lowering surface tension [56]. In addition to ensuring better water quality, NBs' dual function in surface cleaning and water treatment makes surface maintenance in food processing, agriculture, and medical device manufacturing environmentally friendly and effective [41]. [PERSON] et al. [98] revealed that since the 1994 hypothesis of NBs, studies have demonstrated their potential to improve the treatment of water and wastewater, especially the removal of biofilms, by increasing the effectiveness and safety of eliminating various contaminants. The production of ROS by NBs, which are gas-filled structures smaller than 1000 nm, can reduce byproducts and provide a shift away from dangerous chemical oxidants. Most of the research has focused on ultrapure water rather than ordinary wastewater, which makes it more difficult to employ NBs in the real world, even if NB generation and detection have advanced. Key challenges include balancing their dual role in improving biological treatment efficiency while potentially stressing biological cells and understanding the implications of their short-lived ROS. Overall, NBs hold significant promise for enhancing various water treatment processes, including biofilm control. [PERSON] et al. [99] discussed the problem of biofilm formation on polyethersulfone (PES) membranes in the dairy industry, which can endanger public health and food safety. They sought to improve removal from processing equipment and discourage biofilm attachment by creating environmentally friendly methods. The study was conducted in two stages. In Phase 1, the half-life of microscale/nanoscale aqueous ozone (MNAO) was assessed under a range of pH and temperature conditions to determine the ideal parameters for additional research. The efficiency of MNAO in eliminating _Bacillus cereus_ and _Bacillus licheniformis_ biofilms from PES membranes was evaluated during Phase 2. The results demonstrated that MNAO considerably reduced the number of biofilms, outperforming deionized water washes. Furthermore, MNAO improved the effectiveness of biofilm removal when paired with conventional clean-in-place cycles. These results highlighted the necessity for continued research to optimize cleaning procedures and stop biofilm adhesion in dairy processing by indicating that MNAO may be a useful cleaning agent against _Bacillus_ spp. biofilms on PES membranes. [PERSON] et al. [100] revealed the limitations of conventional chemical biocides by demonstrating the effectiveness of NBs in controlling biofouling in agricultural irrigation systems (Figure 14). With high-concentration bubbles outperforming low-concentration bubbles, especially in the early stages of treatment, the study found that NBs significantly reduced biofilm biomass by 31.3-52.1% and extracellular polymeric substances by 16.7-77.6%. Furthermore, the biofilm's microbial community underwent significant changes due to the NBs, which affected mutualistic relationships between species and reduced biodiversity. Additionally, this study discovered that NBs effectively decreased mineral deposition in biofilms by up to 65.7% for silicate and 15.0-42.5% for quartz. Furthermore, the application of NBs increased the average irrigation system discharge rates by 26.7-49.6%.