Sewage Sludge Biochar

The global production of sewage sludge (SS) has accompanied population growth and the expansion of global sewage treatment rates. Sewage sludge is a solid waste rich in nutrients, mainly N, P, Ca, Mg, and Zn. However, SS can also have high contaminating potential. Pyrolysis is an effective technological alternative to transform SS into an agricultural input. The solid product of SS pyrolysis is called SS biochar. In this chapter, we present the state of the-art of SS use in agriculture, highlighting benefits, limitations, and perspectives. Furthermore, we review innovative approaches to render SS biochar production and applicability more efficient and socially acceptable. Such approaches include: (a) SS biochar enrichment technologies; (b) SS biochar for plant disease control; and, (c) SS biochar for soil carbon sequestration. The risks of contamination with heavy metals from SS biochar were also discussed. Finally, recommendations were elaborated for improving the multiple uses of SS biochar in agriculture.