【Objective】 Nitrogen loss from terrestrial ecosystems is an environmental concern in many countries. It is affected by a multitude of biotic and abiotic factors. The purpose of this paper is to investigate the efficacy of soil amendment with straw in ameliorating nitrogen loss from watersheds in the Huaihe River basin. 【Method】 The experiment was conducted indoors using drab soil taken from the field. Artificial rainfall at intensity of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mm/min were applied over the surface of soil amended with crop straw. Water and sediment runoffs from the soil surface, as well as nitrogen loss from both surface and subsurface runoff in each treatment were measured. 【Result】 Accumulative sediment runoff and nitrogen loss from the soil both increased with the rainfall intensity. The nitrogen concentration in the runoff changed more erratically in the first 20 minutes after the commencement of the rainfall, characterized by a rapid increase followed by a long tailing in all treatments. The average nitrogen concentration in the runoff measured from soil without straw amendment peaked when the rainfall intensity was 2.0 mm/min followed by 3.0 mm/min, while amending the soil with straw reduced this to 1.5 mm/min. The amount of nitrogen loss via sediment runoff accounted for 92.8% of the total loss from soil without straw amendment, and this reduced to 59.7% for soil amended by the straw. Soil amendment reduced surface runoff and sediment loss only when the rainfall intensity was low; when the rainfall intensity exceeded a threshold, soil amendment enhanced rather than reduced sediment runoff. Nitrogen concentration in the runoff was higher in soil without amendment than with amendment. 【Conclusion】 Amending soil with straw impacted surface runoff and loss of both sediment and nitrogen, but the effect varied with rainfall intensity. For soil without amendment, the nitrogen concentration in the runoff peaked when the rainfall intensity was 1.0 mm/min, and amending the soil with straw increased this to 1.5 mm/min.

为研究淮河流域农田非点源输出、区域农业非点源污染控制与管理,以河南淮河流域典型土壤(潮土)及其是否秸秆还田为对象,人工模拟0.5、1.0、1.5、2.0、2.5、3.0 mm·min-1降雨强度下的径流、泥沙和氮输出负荷.结果 表明:降雨强度越大,相同时间段内的累积径流量、累积泥沙量、氮输出量以及三者的产出速率均越大;径流中氮元素的浓度在降雨初期的20 min内变化较大,具初期冲刷效应,随后波动并趋于相对稳定或略有降低,其平均浓度在未掺混秸秆时以2.0 mm·min-1降雨强度时最大,其次为3.0 mm·min-1,掺混秸秆后以1.5 mm·min-1时最大;未掺混秸秆时氮元素泥沙输出量占总输出量的98.25％以上,但掺混秸秆后输出量有所降低(最低值为65.12％).秸秆还田后,分别可在<1.0 mm·min-1与<1.5 mm·min-1的低降雨强度下减少径流与泥沙流失量,高降雨强度下则增加泥沙流失量;径流氮元素浓度比未掺混秸秆的高,增加了氮元素的累积输出量.累积径流量与累积泥沙量间及两者分别与氮元素输出量之间均存在良好的幂函数与对数函数关系,相关系数均在0.900以上.研究表明,降雨强度、秸秆还田均对径流、泥沙、氮输出等产生影响,引起氮输出明显变化的降雨强度在未掺混秸秆时为1.0 mm·min-1,在掺混秸秆时为1.5 mm·min-1;减少农田非点源氮输出负荷的重要途径包括控制产流初期氮流失与泥沙流失.

Adsorption of crystal violet (CV) onto amino silica (AS) was investigated as a function of parameters including aqueous pH, temperature, AS dose, contact time, agitation speed, and initial CV concentration. And the optimum conditions obtained from response surface methodology (RSM) were temperature 33 degrees C, AS dosage 0.35 g, contact time 64 min, and agitation speed 230 rpm. The adsorption equilibrium using Langmuir and Freundlich models indicated that the process followed Langmuir isotherm and the maximum adsorption capacity reached 40 mg g(-1). After both pseudo-first-order and pseudo-second-order kinetic models were applied to the experimental data, pseudo-second-order model was found describing the adsorption process very well.

ADC foaming agent condensation water belongs to high concentration ammonia nitrogen wastewater and particularly contains a large amount of refractory material and biological organisms toxic substances.According to this characteristic,experiments of removal of ammonia nitrogen from wastewater by stripping were carried out,influencing factors on the removal rate of ammonia-nitrogen including pH value,temperature,air flow rate and aeration gas were investigated.On this basis,the application of ultrasound to wastewater treatment was studied.The results indicated that the removal rate of ammonia nitrogen reached 92% under the optimal conditions as pH 10,temperature 30 ℃,air flow rate 1.0 L·min-1,ultrasonic power 400 W and ultrasound stripping times of 180 min.

Crystal violet in wastewater was separately degraded by ultrasonic irradiation,ozone oxidizing,and ultrasonic irradiation combined with ozone oxidizing.The effects of initial pH value of wastewater,power and frequency of ultrasonic wave,flow rate of oxygen,and temperature on the degradation rate of crystal violet were investigated.Results indicate that ultrasonic wave irradiation and ozone oxidizing are able to synergistically accelerate the degradation of crystal violet.When the degradation reaction is conducted at an initial wastewater solution concentration of 200 mg · L-1 and pH of 10.0,the removal rate of the total organic carbon can reach as much as 89.2% while the power and frequency of ultrasonic wave,oxygen gas flow rate,temperature,and reaction time are adjusted as 100 W and 30 kHz,0.4 L · min-1,25 ℃,and 90 min.Corresponding pseudo-first-order reaction rate constant is calculated to be 2.38×10-2 min-1.

Technology of direct hot melt, concentration and crystallization to manufacture hydrazine hydrate solid waste into Na2CO3·H2O and Na2CO3 was researched, and principle of process was discussed. Effects of available chlorine dosage, pH value on hydrazine removal rate and crystallization temperature, water evaporation, crystallization time on purity and yield of Na2CO3 were investigated, finding out the optimal technological conditions. This technical process did not cause secondary pollution, products reached standard of GB/T22404-2008 and GB210.2-2004 respectively.

The authors compared identification standard for hazardous wastes-extraction procedure toxicity of China and Japan,and toxicity characteristic leaching procedure of United States to evaluate which is better to identify toxicity characteristic of typical copper catalyst of China.They also studied leaching characteristic of metals in copper catalyst under different pH values.The results showed that pH was a major controlling factor in metal leachability.The metals exhibited a marked increase in leachability at low,while relatively low leachability of these metals were observed at neutral conditions.