Notice of RetractionPilot Study on Hybrid Biological Filter-Coagulation-Submerged Ultrafiltration Membrane for Drinking Water Treatment
Two parallel hybrid processes (Biological filter Coagulation/Ultrafiltration(BCUF) and Coagulation/Ultrafiltration(CUF)) for treating slightly polluted surface water were carried out in this experiment. In the process of BCUF, transverse flow water-dropping aerated biological filter was used as a primary pretreatment, and coagulation was used as the subsequent pretreatment of Ultrafiltration(UF). In the CUF process, coagulation was the unique pretreatment of UF. Turbidity was removed nearly completely in both two hybrid processes, and in the BCUF, effective ammonia nitrogen removal (87.1%) was also achieved mainly through the biological nitrification carried out in the biological filter, however, only 25.6% removal of ammonia nitrogen was achieved in the process of CUF. The removal rates of CODMn, TOC, DOC, UV254, AOC and BDOC were 55.2%, 87.8%, 71.0%, 61.1%, 91.4% and 89.3% respectively in the process of BCUF, which were much higher than that in the process of CUF. The biological pretreatment could improve the biological stability significantly and relieve the membrane fouling which made the transmembrane pressure (TMP) arising velocity lower. The pretreatment of biological filter and coagulation could remove the organic molecules in the range of 5000-500Da. Results showed the water-dropping aerated biological filter was fit for the pretreatment of UF.
Efficiency of the hybrid coagulation–ultrafiltration water treatment process with the use of immersed hollow-fiber membranes
Abstract The changes of concentration of several chemical substances existing in the surface water from the Czarna Przemsza River were examined during the ultrafiltration process carried out with 0.03 m PVDF immersed hollowfiber membranes. The volumetric permeate flux was constant (5.7×10 −6 m 3 /m 2 ·s). The tests were carried out in three ways: ultrafiltration process only and hybrid processes connecting coagulation (with the use of FeCl 3 or Fe 2 (SO 4 ) 3 ) with ultrafiltration. The value of pH in the raw water was about 8.3–8.4. The results of statistical tests show a significant difference between the concentrations of turbidity, total iron, oxygen consumption, COD and absorbance UV (254 nm) during the ultrafiltration process. After the use of both FeCl 3 and Fe 2 (SO 4 ) 3 coagulants, the retention coefficients of turbidity, oxygen consumption and absorbance increased. A minor decline of the retention coefficient of total iron, probably connected with the use of iron coagulants, was observed.
Treatment of fuel oil and crude oil contaminated waters by ultrafiltration membranes
Abstract This study evaluates the effectiveness of ultrafiltration technology for treatment of fuel oil and crude oil contaminated waters. The experiments were conducted by using a laboratory scale continuous cross-flow membrane filtration system manufactured by Desalination Systems, Inc. (DSI). The unit has a maximum operating pressure of 200 psig (13.8 bar) and can be operated in parallel mode with two membranes, each with a 12 in2 area. The water samples were prepared by using either a light crude oil (Boney light) or a mixture of jet fuel, diesel and unleaded gasoline at contamination levels of 150 and 3,000 ppm. The G-50 thin-film composite (TFC) membrane, manufactured by Desalination Systems Inc., was used in the experiments. The G-50 membrane was selected after a series of membrane screening tests. The effectiveness of coagulation prior to ultrafiltration was also studied by using Cat-floc K-10, which was selected after a series of coagulant screening tests.