以新近系明化镇组热储层细砂为岩土介质,在35℃、q为0.8 cm/h条件下,分别以氯离子和硝酸盐作为示踪剂开展室内土柱模拟实验,并采用CXTFTT2.1软件进行数据拟合,研究了硝酸盐运移参数和迁移转化机制.研究结果表明:在模拟的松散孔隙型热储层中,硝酸盐的迁移转化遵循—级衰减动力学假设的溶质对流-弥散模型,其衰减系数拟合值k1为0.019h-1,纵向弥散系数D为3.401 cmVh.实验期间,硝酸盐转化为亚硝酸盐、氨氮的最大比率分别为25.4％、4.37％.亚硝酸盐、氨氮的富集与低的C/N、实验初期亚硝酸盐还原菌的缺乏及水-岩体系pH值有关.实验期间淋出液pH值缓慢下降,ORP下降较快.硝酸盐、亚硝酸盐、EC及TDS变化趋势一致:均为在硝酸盐穿透阶段快速增加、中后期趋于稳定,这说明随着时间的推移,水-岩系统已形成了较稳定的微生物体系,导致硝酸盐转化速率及产物都趋于稳定,并且EC和TDS线性相关.

We analyzed the abundance and connectivity of Cambrian limestone aquifers (CL) using data from geological and hydrogeological boreholes, groundwater tracer tests, groundwater temperature monitoring, and surface transient electromagnetic exploration (TEM). Our results demonstrate that extremely well-developed small faults with an average density of number 73 per square km control the groundwater abundance and flow of the CL. The hydraulic conductivity of the CL aquifers estimated by tracer tests lies between 13,511 and 38,738 m/d, suggesting good connectivity. The surface TEM result of 4.91 km2 shows that areas with an apparent resistivity value less than 30 Ωm can be treated as an anomalous low-resistivity zone. This has been proven to be reliable by experience at the working face and can be used to determine water control measures for future mining. Using these data, we developed a series of preventive measures to mitigate potential floor water ingress related to future mining in the eastern area of the Pingdingshan coalfield No. 2 mine.

The dynamic changes of dissolved organic matter (DOM) during nitrate transport were investigated to explore the relationship between carbon sources and the nitrate reduction process in a loose-pore geothermal reservoir. Batch experiments were performed at four temperature levels (4 degrees C, 25 degrees C, 35 degrees C, and 45 degrees C) to determine the characteristics of the DOM extracted from the geothermal reservoir matrix. According to its fluorescence spectra, fluorescence index (FI), and biological/autochthonous index (BIX), the DOM was mainly derived by autochthonous microbial processes. Column experiments were carried out at 25 degrees C, 35 degrees C and 45 degrees C to determine the dynamic changes of the matrix DOM during nitrate transport in the simulated geothermal reservoir. The dynamic changes of the FIs; the fluorescence intensities (divided by dissolved organic carbon) of peaks B-1 and T-1; and concentrations of NO3--N, NO2--N,NH4+-N and the total dissolved inorganic nitrogen (Sigma N) in the column effluent within 412 h (10.5 PV) indicated that the reduction rate of nitrate and the production of denitrifiers were enhanced with an increase in temperature. Although a red shift of peak T-2 during experiment at 35 and 45 degrees C implied the variation of the aromatic components of DOM during denitrification, low molecular weight aliphatic hydrocarbons in the matrix DOM were more active as electron donors than the aromatic compounds, as indicated by the variations of the effluent pH and SUVA(254) values. No obvious trend in the variation of the BIX with temperature was observed possibly due to the short test duration of the column experiments. The findings should advance our understanding of the biological transformation of nitrate in loose-pore geothermal reservoirs.

To study the structure and type of dissolved organic matter extracted from the fallen leaves of Populus tomentosa,which are widely grown in the geothermal water recharge area in the plain of East Henan,experiments were carried out firstly to determine the optical time of extracting dissolved organic matter (DOM) from the fallen leaves of Populus tomentosa.Then the UV-Vis and three-dimensional fluorescence spectrum of DOM were measured,after which the parameters of SUVA254,A253/A203,A250/A365 and r(A/c)were calculated.The results showed that it is better to extract DOM from the fallen leaves of Populus tomenwsa after oscillating for 24h.DOC is highly linearly correlated with UV2254 indicated by the regression coefficient (R2=0.92) for the studied DOM sample,suggesting that many simple aromatic compounds containing benzene ring exist in the studied DOM and many kinds of aromatic ring substituents contain carbonyl,carboxyl,hydroxyl and lipids.Totally 4 types of fluorescence peak appear in the studied DOM,and the fluorescence intensity in the descending order are humic-like peak (including fulvic-like peak A and humic substances peak C in ultraviolet region),tyrosine aromatic protein peak T and soluble microbial metabolites peak B.At different dilution conditions of DOM samples,the validated structure and relative content of dissolved organic matter with fluorescent properties are slightly different,which are related with the factors such as the pH change of DOM samples,complex composition and disturbance of mixed fluorescent signal.

Dissolved organic matter (DOM) plays an important role in the chemical evolution of groundwater. Thus, in order to understand the composition and characteristics of DOM in groundwater, analyzed 31geothermal water samples from five aquifers (i.e., between 600 m and 1600 m) in the city of Kaifeng were analyzed and the results were compared in order to clarify their spatial distribution, characteristics, sources, and environmental influences. Results show that as the depth of a thermal reservoir increases, the ultraviolet absorption (UV254) of geothermal water does not change significantly, the concentration of dissolved organic carbon (DOC) gradually increases with depth, and the fluorescence intensity of DOM remains weak. Some differences are also evident with regard to the location and intensity of geothermal water sample DOM fluorescence peaks depending on thermal reservoir. The results of this study show that the main source of DOM in geothermal water is endogenous, derived from high stability organic matter derived from sedimentary processes and associated microbial activity. Within the three geothermal reservoir depth ranges, 600 m to 800 m, 800 m to 1000 m, and 1000 m to 1200 m, DOM components were mainly protein-like as well as soluble microbial metabolites. However, at deeper depths, within the 1200 m to 1400 m and 1400 m to 1600 m thermal reservoirs, the proportion of protein-like components in DOM decreased, while the ratio fulvic-like and humic-like components increased, leading to changes in the positions of fluorescence peaks. Finally, our results demonstrate a close relationship between the intensity of fluorescence peaks, suggesting that a number of fluorescent components may share a common source.

To control the three nitrogen compounds pollution of ultra-deep geothermal water effectively and provide theoretical basis for rational development of geothermal water resources,physical and chemical indicators of 44 geothermal wells with depth of 600-1 800 m in the area of Kaifeng City were analyzed,and the spatial distribution characteristics and influencing factors of three nitrogen compounds in the geothermal water were studied based on contour map of three nitrogen compounds concentration in each aquifer.The results showed that the geothermal wells with depths of 600-1 800 m were mainly polluted by nitrite.The pollution of ammonia nitrogen and nitrate was light.Based on Grade Ⅲ of "Quality standard for ground water" (GB/T 14848-93),the nitrite concentration in each aquifer exceeded standard,mainly distributed in the region near the railway station,which was contributed by nitrification/denitrification process.However,ammonia nitrogen and nitrate concentration of each aquifer in the whole research area showed low values except individual sample points.According to correlation analysis,nitrite and nitrate concentration were significantly related,and ammonia nitrogen concentration and pH were also in significant correlation.The relationship between the distribution of the three nitrogen compounds and nitrification,as well as denitrification,were confirmed further.

This paper mainly studied migration and transformation characteristics of dissolved organic matter (DOM) in underground aquifers. To achieve the research purpose, we carried out the dynamic column experiments of the DOM at different conditions indoors. In the experiment, the water of Wujiang River from Pingdingshan Coal-field is used as water sample, meanwhile, fine sand and marl rock are used as testing rock sample. A comparative study on migration and transformation characteristics of the DOM in different rock samples is done. The results show that, in the fine sand, the main effects are convection and dispersion, while the adsorption and biological effects are very weak. However, in the marl rock, besides existing convection and dispersion, the adsorption and biological effect are quite significant. And in the marl rock, convection and dispersion plays a major role in the early experiment, while adsorption is the main effect in the medium term, then the biodegradation dominates the final stage. With the increasing of temperature and seepage velocity in the fine sand, the impact of the convection effect becomes gradually weak, the dispersion effect gradually enhances, and, however, convection effect is still playing a dominant role. With the temperature rising in the marl rock, the adsorption effect becomes weak, but biodegradation is enhanced. As the seepage velocity increases in the marl rock, the adsorption and biodegradation both decrease.

从开封市某酒店1 200 m深地热井中抽取地热水,筛选到1株较高效的好氧反硝化菌A1.对A1进行16S rRNA基因序列测定,确定A1为地衣芽孢杆菌(Bacillus licheniformis).A1在40 h内对硝态氮和TN的去除率分别为96.10％、90.60％.相比亚硝态氮,A1更容易利用硝态氮进行反硝化作用.相比甲醇,琥珀酸钠和柠檬酸钠更适合作为A1的碳源;初始pH对A1的生长量和脱氮效率影响显著,最适初始pH为7.5;A1在25～50℃下均生长良好,并保持较高的脱氮效率,但最适温度为35℃;溶解氧浓度既能影响A1的生长量和硝态氮去除率,还能影响亚硝态氮的积累量,静置培养时,虽然A1生长量不高,但是硝态氮去除率达到90.22％.可见,A1为耐高温的兼性好氧菌.