Which of the following is NOT a commercial waste disposal method for waste solvents?

The correct selection indicates that all the listed methods are recognized approaches to handle waste solvents. Incineration is a widely used method where solvents are burned at high temperatures, effectively reducing them to their basic components, including water and carbon dioxide, while also minimizing their hazardous impact on the environment.

Purification by distillation utilizes differences in boiling points to separate and recover solvents from waste mixtures, allowing for both waste reduction and reclamation of useful materials. This method is particularly significant for recycling solvents in laboratories.

Purification by filtration involves separating solid contaminants from liquid solvents, often facilitating the reuse of the liquid while disposing of the solid waste appropriately.

Thus, the implication of the answer is that each method is indeed a commercial waste disposal approach, leading to the conclusion that none of the methods listed are excluded from being classified as methods for waste solvent disposal.