[Advanced Treatment of Incineration Leachate with O3-BAC and Double O3-BAC].

Ozone-biological activated carbon (O3-BAC) process and double O3-BAC process were respectively used for advanced treatment of the biologically treated effluent of incineration leachate, and their pollutant removal performances were compared. The results showed that the double O3-BAC removed 75.9% ± 2.1% of chemical oxygen demand (COD), 78.8% ± 2.9% of UV254 and 96.8% ± 0.9% of color at ozone dosage of 200 mg x L(-1). The treated effluent was with COD of below 100 mg x L(-1) and color of below 40 times, meeting the emission requirements of GB 16889-2008. At the same ozone dosage, however, the O3-BAC removed 68.2% ± 1.3% of COD, 69.7% ± 0.5% of UV254 and 92.5% ± 1.1% of color. The treated effluent was with COD of around 150 mg x L(-1) and color of about 60 times, failing to meet the emission requirements. Namely, ozone of 290 mg x L(-1) was required by O3-BAC in order to achieve similar pollutant removals as those in double O3-BAC at O3 dosage of 200 mg x L(-1). In double O3-BAC at ozone dosage of 200 mg x L(-1), total phosphorus was removed by 63.5% ± 4.4%, and the phosphorus concentration in the effluent was remained 1 mg x L(-1) or less, directly meeting the emission requirement of GB 16889-2008.

[Variation of pollutants along the height of two media BAF during advanced treatment of dyeing wastewater].

A pilot-scale process with the capacity of 15 t x d(-1) was applied for treatment of the secondary biological effluent from a dyeing industrial park wastewater treatment plant. We studied the variation of pollutants along the height of two media biological aerated filter (BAF), investigated the feasibility of the cheaper and lighter suspended media to substitute activated carbon. The results showed that while the influent average COD and color were 50.2 mg x L(-1) and 58 times, the effluent average COD and color of activated carbon and suspended media BAF were 35.0 mg x L(-1), 18 times and 44.3 mg x L(-1), 26 times, and both of the effluent met the first level A criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002), while it met the first level A criteria at the height of 2 400 mm in suspended media BAF, higher than the height of 1 800 mm in activated carbon BAF. The removal variation of color, TN and ammonia along the height of suspended media BAF is similar to the activated carbon BAF, but with a low removal efficiency of COD, mainly related to its less biomass. Therefore, suspended media to substitute activated carbon is feasible to the wastewater treatment plant, but the size and material of the media still need to be optimized, and to enhance the biomass, the hybrid process of suspended media with activated carbon BAF may be used to reduce the cost if it is necessary.

[Mechanism of membrane fouling and filtration characteristics in a membrane bioreactor for industrial wastewater treatment].

The influence of mixed liquor suspended solids (MLSS), soluble microbial product (SMP), extracellular polymeric substance (EPS), colloidal particles and other factors contributed to membrane fouling was analyzed in this pilot test by membrane bioreactor (MBR) process for the leather printing and dyeing industrial park mixed wastewater treatment. The results showed that slight membrane fouling occurred after 120-day experiment with an observable increase in membrane resistance R20 from 1.5 x 10(12) m(-1) to 1.8 x 10(12) m(-1). Also, a linear correlation was found between the proportion of colloidal particles concentration in TOC of MBR former solution and membrane filtration resistance change. However, the change of MLSS, SMP, EPS and other factors was not correlated with the membrane filtration resistance change. Therefore, the colloidal particle was considered to be the main factor causing membrane fouling, which attached to the membrane surface and deposited to block the membrane pore.

[Study on the pollutants removal performance along the advanced treatment in tannery wastewater by O3-BAF].

A pilot-scale hybrid process of ozone and biological aerated filters (BAF) with the capacity of 36 t x d(-1) was applied for advanced treatment of the secondary biologically effluent from a dyeing and tannery park wastewater treatment plant. The pollutants removal performance along the height of different medias BAFs were investigated. The results showed that the average COD and color were 55.4 mg x L(-1) and 12.6 times at the height of 1500 mm in activated carbon BAF, and were 55.6 mg x L(-1) and 9.4 times at the height of 1 800 mm in composite BAF, both of the effluent at each height met the first level B criteria specified in the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002). Along the height of ceramist BAF, the COD and color were seldom removed. In activated carbon BAF and composite BAF, COD and ammonia nitrogen were both greatly decreased at the height of 1 200 mm, then decreased slowly. The biomasses simultaneously reached the maximum at the height of 900 mm in activated carbon, composite and ceramist BAF, with the maxims of 30.69, 28.87 and 15.94 nmol x g(-1), respectively.