# Treatment Methods for Antibiotic Mycelial Residues: A Review
## 3 Treatment Methods for AMR
### Thermochemical Methods
#### 3.3.3 Hydrothermal Technology  
Hydrothermal treatment (HT) refers to a process conducted under high-temperature and pressure conditions, utilizing water as the reaction medium. By exploiting the unique properties of water in subcritical/supercritical states, this method achieves the detoxification of hazardous compounds and the decomposition of macromolecular organic substances [113; 114]. As a mainstream technology, HT not only disintegrates colloidal structures and biomass matrices to release soluble organic matter into the liquid phase but also eliminates antibiotics in aqueous matrices at subcritical temperatures [38; 53; 114; 115; 116]. For high-moisture feedstocks, like AMR, HT eliminates dehydration pretreatment, reduces energy consumption, enhances conversion efficiency, and mitigates pollutant release associated with conventional dewatering [113; 117].  
Currently, HT is predominantly applied in municipal sludge treatment. Under moderate operational conditions, this method effectively processes urban sludge with high moisture content and pollutant concentrations, achieving significant volume reduction and enabling energy recovery [118]. Both AMR and municipal sludge undergo a fermentation process and both contain mycelium, which is similar in composition. This commonality establishes the feasibility of applying hydrothermal technology to AMR management, supported by substantial research evidence [37]. [PERSON] et al. [59] employed HT to process limomycin mycelial residues. Their results demonstrated effective removal of ARGs and mobile genetic elements, alongside heavy metal immobilization, confirming the capacity of the technology to mitigate environmental risks. [PERSON] et al. [37] conducted systematic investigations on HT for AMR, revealing that the process nearly completely decomposed residual antibiotics while substantially enhancing the dewaterability of AMR solids. Additionally, HT successfully recovered 42.5% of high-calorific solid fuel and reduced the nitrogen content in solid products to 5.8%. Furthermore, [PERSON] et al. [29] and [PERSON] et al. [67] successfully produced high-energy-density bio-oil from AMR via hydrothermal liquefaction. These studies collectively validate that hydrothermal technology not only achieves secure AMR treatment but also enables effective production of clean bioenergy.  
HT can also serve as a pretreatment method for other disposal technologies to enhance the processability of AMR. [PERSON] et al. [5] demonstrated that hydrothermal pretreatment not only effectively degrades residual antibiotics but also breaks down organic particulates in AMR into soluble low-molecular-weight substances, significantly improving its anaerobic digestibility. Following HT, the methane yield of AMR increased markedly from 100 mL/g-VS to 290 mL/g-VS, representing a 190% enhancement in methane production. These results indicate that HT substantially improves the anaerobic digestive performance of AMR.  
HT, as an emerging thermochemical treatment method, has demonstrated multiple advantages in the AMR treatment process. It not only enables deep removal of pollutants to alleviate environmental pressures caused by AMR but also facilitates the production of high-quality fuels and realizes energy recovery from AMR, providing novel insights for achieving reduction, harmlessness, and resource-oriented utilization of AMR. However, industrial-scale application is constrained by challenges: high costs of high-pressure reactors, corrosive media damaging alloy materials, and underdeveloped continuous feeding systems. Future advancements should focus on establishing subcritical catalytic systems, optimizing waste heat cascade utilization, and innovating equipment materials to overcome economic feasibility barriers in large-scale AMR treatment.