危险废物回转窑焚烧系统的工艺设计

介绍杭州市危险废物回转窑焚烧处理示范工程的一期规模、工艺流程及主要设备的设计方法。     

Soil- and surfactant-enhanced reductive dechlorination of carbon tetrachloride in the presence of Shewanella putrefaciens 200

Sorption of organic contaminants to soils has been shown to limit bioavailability and biodegradation in some systems. Use of surfactants has been proposed to reverse this effect. In this study, the effects of a high organic carbon content soil and a nonionic surfactant (Triton X-100) on the reductive dechlorination of carbon tetrachloride (CCl₄) were examined in anaerobic systems containing Shewanella putrefaciens. Although more than 70% of the added CCl₄ was sorbed to the soil phase in these systems, the reductive dechlorination of CCl₄ was not diminished. Rather, rates of CCl₄ dechlorination in systems containing soil were enhanced relative to systems containing non-sorptive sand slurries. This enhancement was also observed in sterile soil slurries to which a chemical reductant, dithiothreitol was added. It appears that the organic soil used in these experiments contains some catalytic factor capable of transforming CCl₄ in the presence of an appropriate chemical or microbial reductant. The addition of Triton X-100 to sand and soil slurries containing S. putrefaciens resulted in increased CCl₄ degradation in both systems. The effect of Triton could not be explained by: (i) surfactant induced changes in the distribution of CCl₄, (i.e. decreased sorption) or the rate of CCl₄ desorption; (ii) a direct reaction between Triton and CCl₄; or (iii) increased cell numbers resulting from use of the surfactant as a substrate. Rather, it appears that Triton X-100 addition resulted in lysis of bacterial cells, a release of biochemical reductant, and enhanced reductive transformation of CCl₄. These results provide insights to guide the development of more effective direct or indirect bioremediation strategies.     

清洁生产与炼油污水回用

该文分析了福建炼化公司炼油污水现状，提出炼油污水回用的可能方式，并进行了初步探讨。     

Effects of oxygen,mannitol and ammonium concentrations on nitrogenase [C2H2] activity in a marine skeletal carbonate sand

Following a lag of 3 to 18 h, acetylene reduction in mannitol-amended sand systems proceeded at approximately constant and high rates for periods up to 4 days. Carbon dioxide production and O₂ consumption were low in these systems in comparison to similar systems additionally amended with ammonium, indicating N-limitation of growth in the former. Thus, long-term acetylene assays of mannitol-amended sand and suspensions from the sand incubated at various partial pressures of oxygen could be used to characterize the O₂-sensitivity of the N₂-fixing bacterial population as a whole, in batch-type systems with a minimal degree of enrichment or change in pO₂ during the course of the assays. Results of various studies suggested that aerobic or microaerophilic N₂-fixing bacteria were absent or scarce in the sand, and that nitrogenase activity occurring in aerobically incubated systems occurred in anaerobic microenvironments. Hydrogen stimulated acetylene-reducing activity, but the time course differed from that of mannitol-supported activity, and proceeded with shorter lags in systems incubated at 0.2 and 0.05 atm O₂ than in systems incubated anaerobically. Efficiency of N₂ fixation [C₂H₂] increased with decreasing initial mannitol concentration. For sand washed with seawater to remove native combined inorganic nitrogen, and amended with 0.015% mannitol, 374 μmoles added NH₄-N/kg wet sand caused almost complete repression of nitrogenase activity, while concentrations as low as 12 μmoles added NH₄-N/kg wet sand appeared to cause at least partial repression of nitrogenase activity. Some implications of these results for the existence of anaerobic microenvironments in the cavities of skeletal carbonates, and for N₂-fixation in the seagrass rhizosphere are discussed.     

Recent developments of safer formulations of agrochemicals

The primary objectives of formulation technology are to optimise the biological activity of the pesticide, and to give a product which is safe and convenient for use. However, because of the wide variety of pesticide active ingredients which are available, many different types of formulations have been developed depending mainly on the physico-chemical properties of the active ingredients. In the past most formulations were based on simple solutions in water (SL), emulsifiable concentrates in a petroleum-based solvent (EC), or dusts (DP) and wettable powders (WP). The presence of petroleum-based solvents in EC formulations and dusty powders in DP and WP formulations can lead to safety hazards in use and a negative impact on the envirnoment generally. Most government and regulatory authorities are now demanding formulations which are cleaner and safer for the user, have minimal impact on the environment, and can be applied at the lowest dose rate. Developments in formulation technology and novel formulation types, sometimes in special packaging such as water-soluble packs, can also give products a competitive advantage, add value or extend the lif-cycle of active ingredients. There is also a demand from government authorities and consumer groups to use safer formulation additives and adjuvants, and to minimise the residues of pesticides on food crops after spraying. All of these aspects are putting increasing pressure on the development of improved formulation and adjuvant technologies. Pesticide formulations for spray application and for seed treatment are discussed, along with developments in bioenchancement.