太阳能水层交换装置设计与试验

随着中国经济的迅猛发展,来自工业、农业和生活的污水不断增多,渔业水域生态环境受到不同程度污染,生态系统健康受到影响。国内外广大学者为此开展了众多关于渔业水域生态修复方面的研究,但缺乏渔业水域生态修复的设备可供利用。研发了一套太阳能水层交换装置,通过曝气的方式推动水体流动,实现上下水层交换,促进有机污染物的有氧降解、净化水质,为沉水植物的生长提供适宜环境,改善不同水域之间的生态联系。该设备以太阳能为动力,全自动定时循环启动,具有结构简单、曝气时间长、动力效率高等特点。2022年9月连续测定试验河道水体中水质状况,分析了太阳能水层交换装置对河道水动力、溶氧含量、氮磷含量的影响。结果显示:该装置每天平均工作时长达8 h,设备周围水体总氮、总磷和氨氮分别与同时期对照组相比降低29.02%、31.25%、62.12%,安装设备的水体中溶氧明显提高,河道中水流流速增加2倍以上,上下水层交换效果明显。研究表明,太阳能水层交换装置有效解决了河道水流流通性不畅等问题,改善了水体环境,对河道水体的生态恢复有积极作用。

基于含水层-钻孔水量交换的疏水钻孔水量计算

疏水降压是煤矿顶板水害防治的主要工程手段,复合充水含水层中倾斜疏放水钻孔涌水量计算及参数优化是需要解决的关键技术。以“渗流-管流耦合模型”理论及能量守恒定律为基础,以含水层-钻孔间水量交换量为耦合点,构建了煤层顶板复合充水含水层倾斜疏放水钻孔定降深放水的含水层-钻孔系统耦合模型,利用母杜柴登矿井临时煤仓放水试验数据验证了模型的可靠性。以此为基础,计算了不同钻孔仰角、数量的钻孔涌水量及单位长度涌水量,确定了钻孔的最佳仰角和数量。同时,计算分析了150 m钻场间距下600 m工作面范围内不同疏降水头的钻孔涌水量、工作面内部降深的特征。结果表明:基于含水层-钻孔水量交换的疏放水钻孔水量计算模型充分考虑了疏放水过程中钻孔内的层流和紊流水流特征。模型计算的1个主放水孔水量和2个观测孔水位历时变化和现场实际情况基本一致,模型可靠性好,且能解决倾斜钻孔在复合充水含水层中的水量分配问题。随着疏放水钻孔仰角的增大,单位长度的钻孔涌水量呈现先增加后减小的趋势,在仰角为60°时,钻孔单位涌水量最大,稳定水量为165 m^(3)/h,主要涌水层位为直罗组一段含水层,约占总涌水量的81%。此外,随着钻孔数量增加,单个钻场内钻孔总涌水量不断增加,单位长度的钻孔涌水量呈现逐步减小的趋势,钻孔数量增至5个后总涌水量基本稳定,钻孔稳定总涌水量约为440 m^(3)/h。在150 m钻场间距下600 m工作面范围中,60 d内,780 m定水头疏降时,钻孔总涌水量由1700 m^(3)/h降至170 m^(3)/h,降幅达90%;830和880 m定水头疏降下,钻孔总涌水量由1530,1350 m^(3)/h分别降至153,135 m^(3)/h,降幅均为90%。钻场内钻孔总涌水量受到周边钻场疏降干扰的影响,由两端向内侧影响逐步增大。780 m定水头疏降时,两端钻孔总涌水量约为309 m^(3)/h,最中间钻场钻孔总涌水量约为142 m^(3)/h。工作面内部水头分别降至780,830和880 m的时间分别为155,125和100 d。随着时间推移,不同降深范围逐步增大。随着疏放时间的延续,横剖面呈现以倾斜钻孔为中心的降落漏斗且范围逐步扩大,平面上则呈现以全部钻场范围为中心的降落漏斗且范围逐渐增大。

Benthic nutrient recycling in shallow coastal waters of the Bohai Sea

Sediment-water fluxes of N and P species in the Bohai Sea were investigated in Septem-ber-October 1998 and April-May 1999. The benthic fluxes of nutrient species were determined by incubating sediment core samples with bottom seawater bubbled with air or nitrogen. -2NO,+4NH, dissolved organic nitrogen (DON) and phosphorus (DOP), total dissolved nitrogen (TDN) and phosphorus (TDP), and -34PO showed a net exchange flux from seawater to sediment, while -3NO, dissolved inorganic nitrogen (DIN) and -23SiO were released from sediment to seawater in the Bohai Sea. Sediment-water nutrient exchange increases DIN and reduces the phosphorus load in the Bohai Sea. The release of silicate from sediment to overlying seawater reduces potential silicate limitation of primary production resulted from decrease of riverine discharge. The exchange flux of nutrients showed no obvious seasonal variation. The present study showed that the concentrations and composition of nutrients in the water column were affected by suspended sediment, and that not all the exchangeable phosphate in sediment could be released via sediment resuspension.

Development of Magnesium-Dominant Soils Under Irrigated Agriculture in Southern Kazakhstan

Irrational irrigation practices in the Arys Turkestan Canal command area in the southern part of Kazakhstan have led to the formation of soils with poor physical and chemical properties. To study whether irrigation and leaching practices and/or groundwater rise have contributed to the accumulation of Mg2+ on the cation exchange complex of these soils, historical changes in soil and groundwater quality were used as source data and the Visual MINTEQ model was applied to analyze the chemical composition of water and soils in the study area. The imposed irrigation regime and the leaching of light sierosem soils led to the dissolution and subsequent leaching of inherent gypsum and organic matter from the soil profile. Further, the domination of bicarbonate in the irrigation water promoted weathering of the carbonate minerals present as calcite. The higher concentrations of Mg2+ in comparison to Ca2+ in the irrigation water resulted in the replacement of Na+ by Mg2+ on the cation exchange complex. In the lower part of the command area, shallow groundwater has contributed to the accumulation of Na+ and to a large extent of Mg2+ on the cation exchange sites.