Extractability of zinc from two types of electric arc furnace fEAF dusts containing 24.8% and 16.8% of zinc respectively (denoted as Sample A and Sample B) were tested using direct alkaline leaching followed by fusion of the resulting leaching residues with caustic soda. The experimental results show that the extraction of zinc iS heavily dependent on the contents of iron in the dusts+The higher iron content. the lower extraction of zinc is obtained. 53% and 38% of zinc can be extracted when both dusts were directly contacted with 5m01. L-0 NaOH solution for 42 h. The remaining zinc left in the leaching residues, which supposed to be present as zinc ferrites, can be further leached when the residues were fused with caustic soda. Quantitative extraction of zinc can be obtained from the leaching residue of Sample A while only 85% from Sample B. The extractability of zinc from dusts with various contents of iron is compared. The production flowsheet for zinc from the dusts using the process proposed is discussed.

Parameters such as pH, concentrations of Cl−, turbidity, NH3-N, CODCr and BOD5 (simplified as COD and BOD respectively in the following text) in leachate generated in the largescale testing landfill unit and closed landfill units at Shanghai Refuse Landfill were monitored from April 1995 to October 1998. The mathematical simulation formula between these parameters and refuse age were established based on the data obtained from the testing landfill unit and justified by the data obtained at the closed landfill units from 1989 to 1993. The long-term predictions for the leachate concentrations for the Landfill were made using the mathematical simulation formula established. It was predicted that the COD and BOD may be reached to the strictest standard for pollution control on municipal solid wastes landfill in China, i. e., COD<100mg L−1 and BOD<30 mg L−1, after 15 yr natural attenuation. The time predicted for NH3-N concentrations to reach the discharging standard, 15 mg L−1, was found to be at least 23-26 yr or even longer. The predictions for concentrations of Cl−, turbidity, and pH values in leachate are also given. The natural attenuation of Cl- is the slowest and might be decreased to 200 mg Cl- L-1, the agricultural irritation standard, after at least 58 yr.

The mechanism of the removal of phosphorus. arsenic and silica from tungstate or molybdatesolutions by synergistic extraction with primary amine and tributyl phosphate (TaP) was investigated. Phosphorus. arsenic and silica were considered to be extracted into the organic phase as heterotungstic or heteromolybdic acids. The composition Of the extracted species is strongly dependent on the concentration of tungsten and moly' bdenum and equilibrium pH values of the aqueous phase. An extraction mechanism based on the formation of hydrogen bonding between the primary amine. TBP and heteropoly acids is proposed. The loaded organic phase was characterized bv UV and IR spectra and by molar conductance. It is proposed from the experimental msulthat the proton transfer from the heteropoly acids to the primary amine in the extracted species occurs intramolecularly. resulting in the formation of ion-associated species, because the primary amine is a weak base and heteropoly acids are strong acids. The mechanism of proton transfer is also proposed.

研究了在上海市老港垃圾填埋场17号填埋单元建造的3000m。小型卫生填埋场垃圾表面沉降规律。结果表明，表面沉降与垃圾的压实程度有关，在填埋过程中，垃圾被充分压实后，沉降就相对较小。在所监测的2.5年时间内，最大累计沉降大于1m，是垃圾填埋初始高度（4m）的25%。根据垃圾表面沉降的预测结果，讨论了老港垃圾填埋场的利用途径和可能性。

A mixed bacterial population was isolated using enrichment in a basal medium containing increasing amounts of fenoxaprop-p-ethyl as a sole carbon source from sludge that had been exposed to fenoxaprop-p-ethyl production wastewater for about 2 years. Eight kinds of isolates could utilize fenoxaprop-p-ethyl, but only one was identified belonging to genus Alcaligenes, named Alcaligenes sp. H. In pure culture, there was 45.8, 66.0 and 69.5% loss of fenoxaprop-p-ethyl (initial concentration: 100, 50, 25 ppm, respectively) as the sole carbon source with biodegradation by Alcaligenes sp. H and fenoxaprop-p-ethyl degradation kinetics obeyed the first-order kinetics, the same as the fenoxaprop-p-ethyl biodegradation kinetics in soil. At least five degradation products of fenoxaprop-p-ethyl biodegradation by Alcaligenes sp. H and two degradation products of fenoxaprop-p-ethyl biodegradation by Huv separated by HPTLC. It is possible that the fenoxaprop-p-ethyl biodegradation by Alcaligenes sp. H includes the same pathway as that by Huv comparing with the Rf.