[Treatment of sulfanilamide production wastewater by resin adsorption technique].

According to the character of sulfanilamide production wastewater, in this paper, the recovery process of sulfanilamide, sodium nitrate in wastewater resulting from manufacturing sulfanilamide was developed by using macro porous resin. The conditions of the resin adsorption and desorption capacity were investigated and the optimal parameters were determined. The results of experiment indicated that this technique was suitable for removal of sulfanilamide from wastewater. About 86% COD removal was obtained under the optimized adsorption conditions, about 86% sulfanilamide and 95% sodium nitrate were recovered from wastewater for possible recycling to the manufacturing process and the recovered sulfanilamide's purity reached 99.8%. The adsorption capacity of resin remained constant during the repetition process of adsorption and desorption. This technique not only eliminates the environmental pollution but also obtain distinct economic benefit.

[Cost-benefit analysis to substituting natural gas for coal project in large Chinese cities].

Since China's large cities were faced with serious coal-smoke pollution with PM10 and SO2 as the main pollutants, natural gas is becoming one of the most attractive clean replacers of coal. To clarify the wide disputation and doubt on the rationality of burning natural gas instead of coal, cost-benefit analysis (CBA) of urban natural gas substitution projects in Beijing and Chongqing was done respectively, in which, the health benefit was carefully estimated with epidemical dose-response function as the main external benefit. The final result shows that in large cities with intensively concentrated population and economic activities, natural gas consumption as municipal civil energy has obvious priority in terms of large environmental benefit from reducing non-point and low-altitude air pollutant concentration. This paper finally recommends that market oriented system reform in natural gas production and retailing system should be considered.