Structural characterization and evaluation of municipal wastewater sludge (biosolids) from two rural wastewater treatment plants in East Texas, USA.

Wastewater sludge (or) biosolids collected from two rural wastewater treatment plants (NWWTP, LWWTP) in East Texas, USA were characterized and evaluated via inductively coupled plasma optical emission spectrometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), and ion chromatography. The proximate organic and inorganic compositions and spectroscopic characteristics of sewage sludge were determined. The results show that the concentrations of toxic metals Cd, Cr, Cu, Mo, Ni, Pb, Hg, and Zn meet USEPA guideline recommendations for land applications.