Petroleum products contamination is a world-wide problem that threatens polluting groundwater and surface water systems. However, the problem is not only large-scale in scope when viewed from a case-by-case basis. Man...Petroleum products contamination is a world-wide problem that threatens polluting groundwater and surface water systems. However, the problem is not only large-scale in scope when viewed from a case-by-case basis. Many fueling, construction, agricultural, and industrial activities result in the problem of managing smaller quantities of these soils from an ecological safety perspective. Landfilling has been the disposal method of choice in the US;however, this option is becoming economically prohibitive and it does not really offer a true degradation fate for the pollutants. This study focused on the proving of an innovative biocell design that afforded a high level of petroleum degradation within a simple and cost effective design. Additionally, the design offered a remediation solution for sites not easily accessed. Soil contaminated with both diesel fuel and gasoline collected from a former filling station was used in this on-site remediation case study. Rapid biodegradation of the petroleum products were observed at the initiation of the study with rates leveling off as the study progressed with the final total petroleum hydrocarbon concentration being 10 mg/kg at Day 90. Oxygen uptake rates were monitored and found to nicely track both microbial activity and pollutant removal dynamics. The biocell design met all expectations by being effective, yet simple to build and operate.展开更多
The froth features in the batch flotation of a sulphide ore were investigated by using the digital image parameters of the froth, the small number emphasis(Nsne), the average grey level(Dagl) and the instability numbe...The froth features in the batch flotation of a sulphide ore were investigated by using the digital image parameters of the froth, the small number emphasis(Nsne), the average grey level(Dagl) and the instability number(Nins), under different conditions of impeller speeds and aeration rates. It is found that the value of Nsne is strongly dependent on the average bubble size of the froth and Dagl on the volume fraction of solid in the froth, and the froth features during the batch flotation are influenced by impeller speed and aeration rate. A kinetic model of the concentrate solid flux was developed which relates the flotation process to the image parameters, Nsne and Dagl of the froth and predictions are well consistent with the experimental data.展开更多
[目的]溶洞的注浆处理是地铁隧道工程中的难点,施工时溶洞的不恰当处理极易引发事故,因此有必要对小型溶洞裂隙数量和注浆压强之间的关系进行研究。[方法]针对需注浆填充的城市小型非连通型溶洞(体积不大于8 m 3)的裂隙数量不确定问题,...[目的]溶洞的注浆处理是地铁隧道工程中的难点,施工时溶洞的不恰当处理极易引发事故,因此有必要对小型溶洞裂隙数量和注浆压强之间的关系进行研究。[方法]针对需注浆填充的城市小型非连通型溶洞(体积不大于8 m 3)的裂隙数量不确定问题,采用Fluent数值模拟软件中的多相流Mixture模型进行不同裂隙数量的溶洞注浆数值模拟,计算模拟注浆时,测试区的注浆压强随时间的变化情况,并与实际工程溶洞注浆压强数据进行对比分析。[结果及结论]对于体积不大于8 m 3的小型非连通型溶洞,其模拟注浆时测试区的注浆压强与裂隙数量呈平方反比关系,注浆压强随着裂隙数量的增加而降低;当裂隙面积达到0.048 m 2时,注浆压强不再降低;注浆压强随着裂隙位置的增高而降低。在实际工程中,可通过对比同类型体积不超过8 m 3小型非连通溶洞之间的注浆压强数据,判断溶洞的相对裂隙数量,调整与优化后续的注浆方案。展开更多
文摘Petroleum products contamination is a world-wide problem that threatens polluting groundwater and surface water systems. However, the problem is not only large-scale in scope when viewed from a case-by-case basis. Many fueling, construction, agricultural, and industrial activities result in the problem of managing smaller quantities of these soils from an ecological safety perspective. Landfilling has been the disposal method of choice in the US;however, this option is becoming economically prohibitive and it does not really offer a true degradation fate for the pollutants. This study focused on the proving of an innovative biocell design that afforded a high level of petroleum degradation within a simple and cost effective design. Additionally, the design offered a remediation solution for sites not easily accessed. Soil contaminated with both diesel fuel and gasoline collected from a former filling station was used in this on-site remediation case study. Rapid biodegradation of the petroleum products were observed at the initiation of the study with rates leveling off as the study progressed with the final total petroleum hydrocarbon concentration being 10 mg/kg at Day 90. Oxygen uptake rates were monitored and found to nicely track both microbial activity and pollutant removal dynamics. The biocell design met all expectations by being effective, yet simple to build and operate.
文摘The froth features in the batch flotation of a sulphide ore were investigated by using the digital image parameters of the froth, the small number emphasis(Nsne), the average grey level(Dagl) and the instability number(Nins), under different conditions of impeller speeds and aeration rates. It is found that the value of Nsne is strongly dependent on the average bubble size of the froth and Dagl on the volume fraction of solid in the froth, and the froth features during the batch flotation are influenced by impeller speed and aeration rate. A kinetic model of the concentrate solid flux was developed which relates the flotation process to the image parameters, Nsne and Dagl of the froth and predictions are well consistent with the experimental data.
文摘[目的]溶洞的注浆处理是地铁隧道工程中的难点,施工时溶洞的不恰当处理极易引发事故,因此有必要对小型溶洞裂隙数量和注浆压强之间的关系进行研究。[方法]针对需注浆填充的城市小型非连通型溶洞(体积不大于8 m 3)的裂隙数量不确定问题,采用Fluent数值模拟软件中的多相流Mixture模型进行不同裂隙数量的溶洞注浆数值模拟,计算模拟注浆时,测试区的注浆压强随时间的变化情况,并与实际工程溶洞注浆压强数据进行对比分析。[结果及结论]对于体积不大于8 m 3的小型非连通型溶洞,其模拟注浆时测试区的注浆压强与裂隙数量呈平方反比关系,注浆压强随着裂隙数量的增加而降低;当裂隙面积达到0.048 m 2时,注浆压强不再降低;注浆压强随着裂隙位置的增高而降低。在实际工程中,可通过对比同类型体积不超过8 m 3小型非连通溶洞之间的注浆压强数据,判断溶洞的相对裂隙数量,调整与优化后续的注浆方案。
