20% waste hydrochloric acid neutralization process

Simple neutralization → sedimentation → filtration using a filter press will meet your requirements. The key factors are the components and total amount present in your waste hydrochloric acid (or nitric acid), as well as what to do with the wastewater after neutralization. In the case of hydrochloric acid, the main component in the treated water is calcium chloride, and such water generally cannot be reused in the system; if it is discharged into inland rivers, discharge is not allowed due to excessive total ion concentration. Discharge into the sea may be possible under certain conditions (it depends on local environmental regulations). In the case of nitric acid, simple acid-neutralization methods are insufficient – biochemical oxidation is required to ensure that the quality of the discharged water meets standards. Therefore, this is a complex process rather than a simple one :)

Do you have a large supply of 31 hydrochloric acid?