Influence of no-tillage on the distribution and lability of phosphorus in Finnish clay soils

No-tillage (NT) is a method adopted to reduce erosion and particulate phosphorus (P) load from arable land to watercourses. However, it has been found to increase the loss of dissolved P with surface runoff, but the reasons for that have rarely been examined in detail. The objective of the present study was to determine the chemical factors explaining this response by investigating the impact of NT on the type and distribution of P reserves as well as on organic carbon (C) in the 0–35 cm topsoil layer of clay soil profiles (Vertic Cambisols). Soil samples were taken from two experimental fields (Jokioinen and Aurajoki) at 0–5, 5–20 and 20–35 cm depths in conventionally tilled (CT) and non-tilled (for 4–5 years) plots. The plots had been cultivated and fertilized according to the common field practices in Finland (15–18 kg P and 100–128 kg N ha⁻¹ year⁻¹).Inorganic and organic P reserves characterized by a modified Chang and Jackson fractionation procedure were not significantly affected by the cultivation methods. However, in the uppermost soil layer (0–5 cm) in NT of the Jokioinen field, the labile P determined by water extraction (P_w) increased significantly, whereas the increase in P extracted with acid ammonium acetate (P_AAC) remained statistically insignificant. The increase in labile P coincided with a significant increase in organic carbon (C), which supports the theory that competition between organic anions and phosphate for the same sorption sites on oxide surfaces will enhance the lability of soil P. In the Aurajoki field with distinct soil cracking, P_w and P_AAC were not affected by NT in the uppermost soil layer, but they increased in the deepest soil layer (20–35 cm) concomitantly with an increase in Al-bound P and organic C. However, the increases were not statistically significant. In both fields, soil acidification due to the repeated application of N fertilizers at a shallow soil depth as well as the accumulation of organic C lowered pH of the uppermost soil layer in NT compared to the deeper soil layers. The results indicated that even short-term NT can increase the labile P in clay soil. However, further studies are needed to assess the long-term changes in lability of surface soil P and, consequently, the possible need for readjustment of the fertilization level in NT.     

GW型加热炉烟气净化系统研究设计

为适应日益严格的环保要求,根据GW型燃油加热炉烟气排放特征和排放规律,设计采用循环流化床工艺进行除尘脱硫。中试结果表明:在最佳工况条件下,系统除尘效率可达97%～98%,脱硫效率达80%～90%,达到国家燃油锅炉一类区域排放标准要求。     

半导体生产排放的废气和废水中砷、磷、硫的分析方法研究

研究了一种快速、灵敏、可靠的高温氢还原-气相色谱分析方法[1-2]，并自行设计了高温还原系统(还原炉、六通阀等)，测定半导体生产排放废气和废水中的砷、磷、硫及其化合物，样品不需预处理，使气相色谱仪能直接测定固、液、气相样品中砷、磷、硫及其化合物的含量。砷、磷、硫的检测限分别为0．01mg／L、0．003mg／L、0．02mg／L；相对标准偏差分别为6．2％、8．6％和0．3％，与经典方法进行对比，结果基本一致。从分析方法的误差统计角度，也说明该方法准确、可靠。     

电凝聚处理轧制乳化废水的研究

用电凝聚法处理轧制乳化废水,探讨了影响破乳的各种因素,确定了最佳处理条件。研究结果表明:该法处理轧制乳化废水的效果很好,浊度去除率可达99.6%,COD去除率达99.5%。此外,还发现电凝聚法的处理效果优于药剂絮凝法。     

皮革和毛皮加工废水处理技术

采用混凝沉淀-酸化水解-悬挂链曝气-生物接触氧化组合工艺处理皮革和毛皮加工生产废水。实验结果表明;进水COD为2400mg/L,处理后出水COD≤100mg/L,去除率≥95.8%。各项水质指标均稳定地达到了GB8978-96污水综合排放一级标准。     

全程自养脱氮工艺的研究

以悬浮填料床作为全程自养脱氮反应器，用不含有机碳的合成氨氮废水进行反应器的启动。系统的氨氮和总氮去除率分别达80％和60％左右。通过批式实验对全程自脱氮做进一步的研究。结果表明，通过控制反应器中DO的浓度，可以控制氨氧化和反硝化的比率；当DO为0.8mg/L时，氨氮几乎完全转化为氮气，氨氧化和反硝化在此时达到了动态平衡；在低DO情况下，氨氮和亚硝氮同时存在，氨氮和总氮的转化率都大幅度的提高，说明氨氮可以亚硝氮为电子受体，在无外加有机碳源的情况下进行反硝化。     

人工神经元网络对水处理系统建模适应性的研究

针对水处理系统的特点和研究中的难点，引入人工神经元网络的理论和思想，提出了水处理系统的神经网络分析方法．通过建立基于ＢＰ人工神经元网络的臭氧生物活性炭系统的模型，具体地考察了人工神经元网络对水处理系统建模的适应性，使水处理系统的研究迈向智能化和控制化．     

湖泊、水库水的强化混凝除藻的试验研究

就高锰酸钾复合药剂强化混凝对湖泊、水库水中藻类的去除进行了研究，试验表明：投加一定量的高锰酸钾复合药剂可显著提高水中藻类的去除率。将经与预氯化、预投加高锰酸钾除藻工艺进行比较，表明高锰 酸钾复合药剂强化混凝除藻效率明显优于传统预氯化、预投加高锰酸钾除藻工艺。     

大型构件防腐喷砂(涂)车间通风除尘设计

考虑到大型构件喷砂（涂）车间铝粉尘污染的特点以及构件进出空间的限制，比较了各种类型的除尘器，选择了最合理的通风除尘方案，进行了通风除尘系统的设计。该设计方案实施后，除尘效果显著。     

气浮--厌氧--生物接触氧化工艺处理屠宰废水

介绍了采用气浮-厌氧-生物接触氧化工艺处理屠宰废水的工程实例。当进水CODcr≤4500mg／L时，出水可达到国家《肉类加工工业污染物排放标准》(GB13457—1992)一级标准。