الفهرس 
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Abstract
This study introduces an application of chemical treatment and biological treatment for industrial wastewater (IWW), which is contaminated with sulfate ions. Thus, lab scale chemical treatment system and anaerobic bioreactor were fabricated for determining the optimum operational conditions for remarkable removal of sulfate ions and other impurities from IWW. Chemical treatment of Sulfate involves advanced calcium-aluminum precipitation (ACAP) method that greatly enhanced the precipitation of sulfate ions as a mixture of gypsum CaSO4.2H2O and ettringite Ca6Al2(SO4)3(OH)12.26H2O via addition of lime (CaO) and aluminum in the form of sodium aluminates (NaAlO2). The optimum operational conditions for ACAP method were: the pH range from pH 11.0 ~ 12.5, the molar ratios of Ca(OH)2 to NaAlO2 to Sulfate, SO42− (Ca : Al : SO42-) were 6 : 1 : 3, retention time of 30 min., and at normal temperature of 25oC. Consequently, XRD, SEM and EDAX analyses identified the chemical formula of precipitate as ettringite Ca6Al2(SO4)3(OH)12.26H2O. Ettringite was dissolved in acidic solution and gypsum precipitated and aluminium recovered. Experimental results indicated that the ACAP method reduced the sulfate with higher removal efficiency, more than 98%. In addition, the method can effectively remove the heavy metals like Cr, Ni, Cd, Pb, Fe, Mn and Zn, with noticeable removal efficiencies more than 99%. On the other hand, Biological treatment of sulfate has been carried out by using up-flow anaerobic sludge blanket, UASB Bioreactor. SRB can consume sulfate during respiration and reduce sulfate into sulfide and H2S(g) liberates. The produced sulfide helped the heavy metals to be precipitated as metal sulfide. Within one year and along 345 days of operational time, and at pH 6.2, when HRT was decreased from 24 h to 18 h and increase in the SLR up to 1.3 g SO42- L-1 d-1, the sulfate reduction efficiency improved from (53±11) up to (87±7) %, and an effective removal of heavy elements reached 99%. However, when HRT was decreased to 12.0 h and SLR increased up to 3.6 g SO42- L-1 d-1, the sulfate reduction efficiency decreased to (66±3¬¬) %. When temperature increased from 25 oC to 35oC, the sulfate reduction efficiency increased from 68 to 83 %. When COD/SO42- ratio increased from 2.0 to 5.0, the sulfate reduction slightly decreased from (74 ± 10) to (68 ± 6) %, When COD/SO42- ratio increased from 5.0 to 10.0, the sulfate reduction decreased from (68 ± 6) to (66 ± 3) %. The full-operational conditions of the UASB reactor were set at temperature, HRT, SLR, and COD/SO42- ratio of 35 oC, 18 h, 1.3 g SO42- L-1 d-1, and 2.0, respectively, and Fe2+ is essential.