No abstract

To provide beneficial guide for the application of the magnetic field in the bio-treatment of the Cr(VI)-contained wastewater, sludge samples from the control bio-system A (absent of magnetic field) and the contrast bio-system B (present of magnetic field) were used to adsorb the synthetic wastewater with 100 mg l(-1) Cr(VI). Influences of two adsorption modes, single adsorption and once continuous adsorption, on the Cr(VI) adsorption capacities of both sludge samples were compared. And the influence of regeneration on the Cr(VI) adsorption capacities were also studied. The results of adsorption experiments showed that the Cr(VI) adsorption capacities of the first single adsorption for sludge sample A and B were pretty nearly, which were 9.79 and 9.93 mg, respectively. And after 5 single adsorption periods, the total Cr(VI) adsorption capacity and efficiency of the sample B were 25.88 and 55.66 mg Cr(VI) g(-1)VSS, while those of the control were 14.95 and 33.98 mg Cr(VI) g(-1)VSS, respectively. For the sludge sample A and B after a single adsorption, both functions of regeneration were remarkable. But after 13 cycles of the single adsorption-regeneration, the Cr(VI) adsorption capacity and efficiency of the sample B were 110.15 and 189.91 mg Cr(VI) g(-1)VSS, while those of the control were 70.89 and 140.38 mg Cr(VI) g(-1)VSS, respectively. Though the Cr(VI) adsorption capacity of a once continuous adsorption period was more than that of a single adsorption period obviously, the Cr(VI) removal rates of the sludge sample A and B in the third period of once continuous adsorption-regeneration were only 8.12 and 33.51%, respectively. It was concluded that the weak magnetic field did improve the Cr(VI) bio-removal efficiency and the sludge stability, the batch treatment was an ideal operation mode for the bio-treatment of the Cr(VI)-contained wastewater, as compared with the continuous operation mode, but regeneration and enough sludge content were two necessary conditions to ensure the efficiency of batch treatment.

Two modes of magnetic fields were applied in the Cr(6+) removal sludge reactors containing two predominated strains--Bacillus sp. and Brevibacillus sp., respectively. The magnetic field mode I* of 0-4.5 or 0-14 mT between pieces was obtained by setting the magnetic pieces with the surface magnetic density of 0-6 or 0-20 mT into the reactor, and the magnetic field mode II* of 6, 20, or 40 mT on the return line was obtained by controlling the working distance of the permanent magnet outside the sludge return line. The effects of different magnetic fields on the activity of the given anaerobic sludge were studied by comparing with the control (absent of magnetic field). The results showed that the magnetic field of 0-4 mT improved the activity of given sludge most effectively, U(max) CH(4) (the peak methane-producing rate) and the methane producing volume per gCOD(Cr) reached 64.3 mlCH(4)/gVSS.d and 124 mlCH(4)/gCOD(Cr), which increased by 20.6 and 70.7%, respectively, compared with the control. And the magnetic field of 20 mT took second place. It could be concluded that the input of some magnetic field could improve the activity of anaerobic sludge by increasing the transformation efficiency of COD(Cr) matters to methane, and the total organic wastage did not increase.

The effects of packaging container on quality characteristics of peanut oil were investigated in this paper. Peanut oils were stored in two containers respectively: folding Polyethylene terephthalate (PET) bottles and common PET bottles. Peroxide value (PV), tocopherol and fatty acid composition of peanut oils were determined after 9 weeks of storage. Results showed that the PV of peanut oils in folding PET containers was significantly less than that of common PET bottle during storage period. The decrease extent of unsaturated and saturated fatty acid of peanut oils in folding PET containers was less than that of common PET sample. The degradation speed of fatty acid could be restrained by folding PET container. α-, and δ-tocopherol losses of peanut oil in the folding PET container were significantly reduced.

As a major part of the Dianchi Lake, the Caohai Lake is in a serious eutrophication situation, which is imminent for pollution treatment. An improved floating bed, which called combined packing with emergent aquatic plants canna indica, submerged aquatic plants Hydrilla verticillata and aeration device, was used to purify the water taken from the Caohai Lake. Compared with the traditional floating bed called combined packing with emergent aquatic plants canna indica and aeration device, the purification effect in the improved floating bed is obviously superior. The removal rate of CODcr, TN, TP in the improved floating bed can reach to 84%, 87.4% and 94.2%, which were 16% of CODcr, 12.2% of TN, 13% of TP higher than that in the traditional floating bed system after 25th days in motion. The result demonstrated that the Hydrilla verticality play an important role in the improved floating bed water treatment system. The improved floating bed is effective and reasonable for the purification of Caohai Lake water and it has great value in application and significant meaning in practice.