Evaluation of Groundwater Suitability for Irrigation and Drinking Purposes in an Agricultural Region of the North China Plain

Groundwater is an irreplaceable resource for irrigation and drinking in the North China Plain, and the quality of groundwater is of great importance to human health and social development. In this study, using the information from 59 groups of groundwater samples, groundwater quality conditions for irrigation and drinking purposes in an agricultural region of the North China Plain were analyzed. The groundwater belongs to a Quaternary loose rock pore water aquifer. The depths of shallow groundwater wells are 20–150 m below the surface, while the depths of deep groundwater wells are 150–650 m. The sodium adsorption ratio (SAR), sodium percentage (%Na), residual sodium carbonate (RSC), magnesium hazard (MH), permotic index (PI) and electrical conductivity (EC) were selected as indexes to evaluate the shallow groundwater suitability for irrigation. What’s more, the deep groundwater suitability for drinking was assessed and the human health risk of excessive chemicals in groundwater was studied. Results revealed that SAR, Na% and RSC indexes indicated the applicability of shallow groundwater for agricultural irrigation in the study area. We found 57.1% of the shallow groundwater samples were located in high salinity with a low sodium hazard zone. The concentrations of fluorine (F−) in 79.0% of the deep groundwater samples and iodine (I−) in 21.1% of the deep groundwater samples exceeded the permissible limits, respectively. The total hazard quotient (HQ) values of fluorine in over half of the deep groundwater samples exceeded the safety limits, and the health risk degree was ranked from high to low as children, adult females and adult males. In addition to natural factors, the soil layer compression caused by groundwater over-exploitation increased the fluorine concentration in groundwater. Effective measures are needed to reduce the fluorine content of the groundwater of the study area.

Integrated studies to investigate paleochannel aquifer in Dan Chang District, Suphan Buri Province, Western Thailand

Climate change is currently causing droughts in many parts of Thailand, especially in Dan Chang District, Suphan Buri Province where many areas are outside irrigation coverage and deep groundwater explorations are less successful due to groundwater shortages. Therefore, there is a need to explore other shallow groundwater (i.e. less than 15 m deep) resources to relieve the drought problems in the communities. This work uses integrated studies of remote sensing, geology and geophysics to identify the location of a paleochannel that contains shallow groundwater resources in the Nong Makha Mong Subdistrict, Dan Chang District, Suphan Buri Province. Potential sites were selected using preliminary remote sensing analysis along with field surveys. A high-resolution topography map from aerial photos was generated and 2D resistivity imaging surveys were conducted at the selected sites to delineate the location of the paleochannel. The drilled wells prove the success of the integrated study to identify the shallow groundwater in the paleochannel at a depth of 3 to 15 m with a groundwater yield of 4 m3/h. The sediments from the borehole suggest that a combination of alluvial deposits and fluvial sediments. Due to the relative lower cost of drilling shallow wells, this work could be used as a pilot project for local communities to explore shallow groundwater aquifers in paleochannels in areas that face a severe drought crisis and have very little deep groundwater potential.

PROPOSAL OF A SOLUTION FOR WATER DESALINIZATION USING SOLAR ENERGY

Water is abundant on Earth, only about 2.5% is freshwater, and because most of that water is stored as glaciers or deep groundwater, only a small amount of water is easily accessible to humans and animals. This study's motivation is to find a solution for lacking freshwater, converting brackish and seawater to potable water. The main goal was to produce potable water with high-efficiency production using solar energy. The system's main components were the absorber plate painted black, glass cover, insulation, and vessels to collect fresh water. The absorber plate is painted black to absorb solar radiation, preventing its reflection. The plate delivers higher temperatures for saline water to be evaporated and condensed afterward. The basin liner was made of an iron sheet, and the cover is made of ordinary glass, while the basin was covered with glass using silicon rubber. We used 30-degree single slope solar to identify the efficiency of using black stone without using black stone (control). The results showed that the maximum output with black stone and without it was respectively 750 ml and 600 ml; therefore, the use of black stone can increase the productivity for the single slope solar still.Keywords: Solar collector; Potable water; Brackish water.