پديد آورندگان :
كريمي، ناصر دانشگاه صنعتي سهند , حضرتي، حسين دانشگاه صنعتي سهند - دانشكده مهندسي شيمي , فاتحي فر، اسماعيل دانشگاه صنعتي سهند - دانشكده مهندسي شيمي
كليدواژه :
بيوراكتور غشايي , فاضلاب پتروشيمي , كاهش گرفتگي , جاذب كربن فعال گرانوله
چكيده فارسي :
در اين تحقيق بيوراكتور غشايي غوطه‌ور براي تصفيه فاضلاب مجتمع پتروشيمي مورد بررسي قرار گرفت. لجن اوليه در اين تحقيق از لجن برگشتي سيستم تصفيه فاضلاب مجتمع پتروشيمي تهيه شد. غشاي مورد استفاده در اين پژوهش، مسطح و از جنس پلي وينيليدين فلورايد بود. سايز حفره ها، تخلخل و ميزان سطح براي غشا به ترتيب، 1/0 ميكرون، 73% و 004/0 مترمربع بود. در اين مطالعه، توزيع اندازه ذرات، SMP، EPS براي لجن اندازهگيري شد. همچنين براي تعيين مشخصات كيك از تست FTIR نيز استفاده شد. ميزان فشار بحراني براي غشاي مذكور نيز اندازهگيري شد كه مقدار آن kPa 2/0 بدست آمد. اين تحقيق در دو مرحله جداگانه انجام گرفت. در مرحله اول، پايلوت براي 35 روز به‌صورت پيوسته عمل كرد. نتايج به دست آمده نشان داد كه با وجود گرفتگي غشا، شار خروجي غشا از بازده مطلوبي برخوردار بود و بعد از هر دوره 7 روزه، بازيابي شار خروجي بيشتر از 90 درصد را نشان داد. در اين مطالعه حذف COD بيشتر از 85 درصد، در شرايط MLSS و HRT به ترتيب،300±3000 ميلي‌گرم بر ليتر و 14-16 ساعت حاصل شد. علاوه بر آن، TSS و كدورت در خروجي به ترتيب، كمتر از mg/L 1 و NTU 12 حاصل شد. در مرحله دوم از كربن فعال براي كاهش گرفتگي غشا استفاده شد. در راكتور حاوي كربن فعال، ميزان افت شار، 22 درصد كمتر صورت گرفت كه از جمله دلايل آن مي‌توان به افزايش اندازه لخته‌ها، كاهش SMP در لجن و كاهش مقاومت حفرات غشا اشاره نمود
چكيده لاتين :
In this study, petrochemical complex wastewater was investigated by submerged membrane bioreactor (MBR).
Initial sludge was prepared from returned sludge of petrochemical complex wastewater treatment plant.
Applied membrane is of micro-filtration type made of polyvinylidene fluoride with effective surface of 0.004
m2, porosity of 73% and nominal pore diameter of 1 μm. Particle size distribution (PSD), soluble microbial
products (SMP), and extracellular polymeric substance (EPS) for sludge were measured. In addition Fouriertransform
infrared spectroscopy (FTIR), and EPS analysis were performed for determining the properties of
the formed cake. Also was measured critical pressure for membrane in the MBR. The critical pressure value
was 0.2 kPa. Therefore, the operating pressure was selected 0.12 kPa. This research was conducted in two
phases. In the first phase, the pilot worked for 35 days. The results showed that despite the membrane fouling
in initial days, the permission of the membrane still had a good efficiency, and after each 7 days, the membrane
was cleaned physically and chemically, which showed a recovery of permeate more than 90%. The COD
removal efficiency was achieved more than 85% in MLSS=3000±300 mg / L and HRT=14-16 hours. In
addition, the TSS and turbidity in the output were below 1 mg/L and 12 NTU, respectively. In the second
phase, for reducing fouling, the granule activated carbon was added in the sludge. In the reactor containing
activated carbon (R2), membrane fouling was carried out with lower rate and also flux drop was lower about
22% compared to reactor without activated carbon. This phenomenon was due to increasing sludge particle
size, SMP reduction. The variation range of SMP was 60-71 mg/l and 60-37 mg/l for the R1 and R2,
respectively; Their EPS varied between 58 to 62 mg/l and 58 to 59 mg/l for R1 and R2, respectively. SMP and
EPS variations had nearly constant trend for R1 and showed no significant increase during treatment process.
While, for R2, SMP concentrations had descending trend and their values were less than R1 throughout the
process. The PSD results show that inclusion of activated carbon in the system causes the flocs to grow bigger.
It can be seen that average particle size in R2 (65 μm) is larger than R1 (38μm). Therefore, larger flocs create
higher porosity which cause less membrane fouling and as a result, cake resistance is decreased. , FTIR analysis
was carried out. The obtained results show that the foulants in the cake layer were typically polysaccharides
or polysaccharides-like substance and proteins (Amid I, II, III). Three peaks at the wavelengths of 1385, 1540
and 1640 cm-1 corresponded to the presence of Amide III, II and I, respectively. Further, the peaks of 1055
and 2930 cm−1 are peaks due to polysaccharide-like substances. As it can be seen, organic compounds such
as polysaccharides, proteins, aromatic hydrocarbons and aliphatic hydrocarbons exist in both cakes. On the
other hand, it can be seen that in activated carbon-containing reactor, all the peaks have lower intensity in
comparison with the R1.
