Fig. 1. X-ray diffraction (XRD) patterns of the ferrous sulfate (Fe-sul)-stabilized and untreated (the lowest Fe to P molar ratio) sludge. Mineral symbols are as follows: BR, brushite; G, gypsum; VA, ferrian variscite; LI, lipscombite; RO, rozenite; SD, siderotil; HJ, hydronium jarosite; MG, magnetite; CR, cristabalite; Q, quartz; C, calcite; V, vaterite; and DO, dolomite.