A new insight into resource recovery of excess sewage sludge: Feasibility of extracting mixed amino acids as an environment-friendly corrosion inhibitor for industrial pickling

- A value-added product was extracted from the municipal excess sludge.
- The effective components contained in the product were mixed amino acids.
- The product could provide a reliable protection to the steel from the acid medium.
- A new insight into the resource recovery of excess sewage sludge was provided.