Search Results (3)

A general and precise protocol that follows the standards of an inverse problem in engineering is proposed to estimate groundwater velocity from experimental lectures of temperature vertical profiles in a 2D aquifer. Several values of error in the temperature measurements are assumed. Since a large quantity of parameters and initial conditions influence the solution of this process, the protocol is very complex and needs to be tested to ensure its reliability. The studied scenario takes into account the input temperature of the water as well as the isothermal conditions at the surface and bottom of the aquifer. The existence of an input region, in which profiles develop to become linear, allows us to eliminate experimental measurements beyond such a region. Once the protocol is developed and tested, it is successfully applied to estimate the regional (lateral) groundwater velocity of the real aquifer and the result compared with estimations coming from the piezometric map. Full article

[Objective] The irrigation area in northern Henan is an important grain producing area in China. Native high arsenic groundwater exists in the area and has long been used for agricultural irrigation. Increased soil arsenic (As) content under long-term irrigation threatens the quality and safety of crop products. Soil passivation is the use of adding passivators to the soil to fix pollutants to achieve the purpose of limiting their migration. Therefore, the preparation of an efficient and clean passivator and its arsenic fixation effect in soil are important research areas to reduce the risk of high arsenic groundwater. [Method] Firstly, nano-manganese dioxide (MnO₂)-modified biochar was prepared via the pyrolysis of sawdust biochar, potassium permanganate and manganese sulfate monohydrate at a mass ratio of 1:0.18:0.29. Secondly, the adsorption characteristics were explored using adsorption kinetics and adsorption isothermal experiments. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD) feature mapping and other characterization methods were used to study its physical properties and adsorption mechanism. Finally, a potting experiment was designed to explore the changes in arsenic content in soil when the passivator dosages were 0%, 1% and 5%. [Results] (1) The nano-MnO₂ modified biochar could reach the adsorption dynamic equilibrium after 180 min, and its maximum adsorption capacity was 58.12 μg/g. (2) When the dosing ratio was 1%, the fixed efficiency of soil effective As content in potted crops of unplanted crops and planted crops was 4.18–5.51% and 1.99–3.83%. When the dosing ratio was 5%, it was 7.48–8.75% and 5.58–9.58%. [Conclusions] The results show that when the addition ratio is 0–5%, the passivation effect of soil effective As is positively correlated with the passivator dosage. Full article

The utilization of groundwater is becoming increasingly popular for heating and cooling buildings, as well as to regulate the temperature needs of industrial processes. Groundwater has excellent energy potential from various factors, of which environmental acceptability stands out, as groundwater is considered a source of renewable energy. Due to the water table depth below the surface, atmospheric conditions have a negligible effect on the temperature of groundwater, resulting only in minor annual temperature variations, thus also making groundwater a source of reliable renewable energy. This paper presents some aspects of the groundwater heat pump (GWHP) system’s design and addresses a particular problem on the influence of recharge temperature field as well as local utility lines on the pumping well water temperature. An example is given of a system designed for a production hall in the northern part of Croatia. Geological and hydrogeological conditions at the site are highly favourable regarding the groundwater temperature and aquifer parameters. For the needs of this research, precise electronic sensors with data loggers were installed inside the wells. Probe type GSR 120 NT manufactured by Eltratec, Slovenia, is capable of monitoring level, temperature, and electrical conductivity, including telemetric data transfer to the remote server. Mapping the obtained data revealed significant temperature breakthroughs from the recharge wells, as well as local temperature field deviation near the sanitary and precipitation drainage collectors. Utility installation seepage influence was differentiated by the increase in groundwater electrical conductivity measured at the pumping wells. Results show that not only distance between the wells, as the main parameter that affects the system, but also industrial utility lines can have an influence on thermal field breakthrough. Full article