Algae colonisation has been observed on silicone rubber insulators around the world especially in a subtropical climate because the moderate temperature and moisture could aggravate the growth of algae upon silicone rubber material. The surface of these insulators easily forms a water film, and the originally excellent hydrophobicity is decreased or even destroyed. This study explores the regularity of the hydrophobicity changes and the underlying mechanism. Based on the solid layer method, silicone rubber samples were found with algae and inorganics quantitatively, and their contact angles were measured after reservation under different humidity levels. The results showed that although inorganic ash could accelerate the hydrophobic recovery process, algae colonisation decisively decreased the hydrophobicity, especially in moist climates. After an extensive investigation of biological contaminants, it was found that the appearance of algae was independent of inorganics, but algae could accelerate the accumulation of inorganics through water absorptivity and the viscosity of secretions. The water absorption ability of algae was compared with that of inorganic ash and sugar, and their difference was deduced to be due to the environmental adaptability of the algae organisms, which was reflected mainly in a dry climate. The microscopy analysis of bio‐contaminants was conducted through SEM.

Composite insulators are widely used in the external insulation of transmission lines due to their excellent pollution flashover resistance. However, the large amount of silicone rubber material is difficult to degrade naturally in decommissioned composite insulators resulting in great pressure on the environment. A method for recycling waste silicone rubber by microbial degradation was proposed. The insulator shed materials of composite insulators naturally retired under 10–15 years of operation are collected. Using dominant species to decompose silicone rubber, the decomposed product is obtained, and the chemical reaction process is deduced according to the three-dimensional structural characteristics of monomers. The biodegradation process does not require the participation of a strong acid and alkali, and the recovery method is safe and effective. At the same time, the nano-silicon dioxide is separated from the waste silicone rubber and modified by the surfactant. The particle size of nano-silica is reduced to ∼18 nm with an excellent dispersibility, indicating high economic value. It is demonstrated that microbial decomposition recycles polymeric materials with the ability to turn them into a valuable resource, which is a very-low-carbon green and environment-friendly method of recycling.