Microbial community composition and environmental response characteristics of typical brackish groundwater in the North China Plain

To reveal the microbial community composition of regional shallow porous brackish groundwater and its response characteristics to groundwater environment,the first and second aquifers in Taocheng District,Hengshui City were selected,and 10 groundwater source samples were collected for hydrochemical analysis and microbial 16S RNA gene V4-V5 regional sequencing.The results showed that the shallow brackish groundwater in the study area is weakly alkaline and has high ion content.The hydrochemical types are SO_(4)·Cl-Na·Mg type and HCO3·Cl-Na·Mg type as a whole.The spatial zonation of the abundance and diversity of groundwater microorganisms is obvious.The number of endemic bacteria in groundwater from upstream,midstream to downstream is 11,135 and 22 respectively,with a total of 22 bacteria.Proteobacteria is the most dominant in groundwater level(38.82%-86.88%),and there are obvious differences in different sections.At the genus level,the main dominant species in each group and sample are Pseudomonas and Hydrogenophaga.In terms of composition difference,Pseudohongiella,Pseudorhodobacter and Limnohabitans are the representatives of UR,MR and LR.On the whole,the composition of flora in groundwater in the study area is sensitive and closely related to hydrochemical processes.Species abundance is affected by alkaline and high salinity environmental indicators,while species diversity is related to depth and dissolved oxygen in weak reduction environment.

Hydrogeophysical and Structural Investigations Using VES: A Case Study of Dosso Region in the Southwestern Part of the Meso-Cenozoic Iullemmeden Basin (Southwestern Niger)

A regional study connecting geolelectrical surveys with geology and hydrogeology was carried out in the western part of the Iullemmeden basin, precisely in the Dosso region in Niger. One hundred and four (104) vertical electrical sounds have been realized, among them nineteen representative were thus be used as parametric surveys. The local resistivity values of the geological formations of Quaternary range from 100 Ω⋅m to 1000 Ω⋅m (sands and lateritic sandstones). The Oligo-Miocene formation of the Continental terminal (Ct) shows resistivity values ranging from 1 to 5 Ω⋅m (brackish groundwaters) to 1500 Ω⋅m (clay sandstones) while the Upper Cretaceous formation of the Continental “hamadien” (Ch) indicates values ranging from 20 Ω⋅m (sandy clay) to 5000 Ω⋅m (clayey sandstones). The geological formations of Paleocene have values from 2 Ω⋅m (marls) to 60 Ω⋅m (calcareous marl), while the Precambrian basement exhibits values of granite around 300 Ω⋅m to 60,000 Ω⋅m. The update of the structural settings reveals many faults in the study area which explain both the shape of the basin and the geometry of the aquifers. Tectonics is also consistent with the hydraulic characteristics of aquifers. In addition, brackish groundwaters were identified as perched aquifer groundwaters in different depths in Dosso region. They probably come from the marine brines during the regression of the Paleocene Sea.

Effect of Using Magnetic Brackish Water on Irrigated Bell Pepper Crop （Capsicum annuum L.） Characteristics in Lower Jordan Valley/West Bank

Increasing salinity of the groundwater is one of major challenges faced by agricultural sector in West Bank/Palestine. This study was carried out in the Lower Jordan Valley （LJV） under greenhouse field condition, where an area of 0.12 ha was irrigated with 3.5 dS/m magnetic treated water during the growing season 2012/2013. The results of this pilot project show that there are significant increases in the yield of red and yellow bell pepper of about 20% and 18% on fresh weight basis, respectively. Water use efficiency increased by 15% and an increase in shelf time of 7 d were also recorded. The chlorophyll content raised significantly in the leaves of treated plants compared to the controlled one by 2.5 mg/g. Bell pepper irrigated with magnetic water produces 37% more four champers than that of the controlled one. On the other hand, there were no clear significant effects on the height of the plant, number of fruits, distance between nods, size of fruits, number and thickness of walls and sugar contents. Applying visible/near infrared （VIS/N｜R） spectroscopy test shows that it is possible to distinguish between treated and controlled bell pepper fruits. Multivariate data analysis （MVDA） method was used to test the classification of chemical elements in the fruit and it was found that treated and controlled fruit samples are divided into two groups according to their water treatment. An increase in all nutrient concentrations was found in fruits irrigated with magnetic treated water compared with the controlled one. Further testing is needed especially by involving other variables such as decreasing the volume of irrigated water and fertilizers.

Fluoride removal from brackish groundwater by direct contact membrane distillation

The direct contact membrane distillation applied for fluoride removal from brackish groundwater was investigated. The self-prepared polyvinylidene fluoride membrane exhibited high rejection of inorganic salt solutes. The maximum permeate flux 35.6 kg/（m^2-hr） was obtained with the feed solution at 80℃ and the cold distillate water at 20℃. The feed concentration had no significant impact on the permeate flux and the rejection in fluoride. The precipitation of CaCO3 would clog the hollow fiber inlets and foul the membrane surface with increasing concentration factor when natural groundwater was used directly as the feed, which resulted in a rapid decline in the module efficiency. This phenomenon was diminished by acidification of the feed. The experimental results showed that the permeate flux and the quality of obtained distillate kept stable before concentration factor reached 5.0 with the acidified groundwater as feed. The membrane module efficiency began to decline gradually when the feed continued to be concentrated, which can be mainly attributed to the formation of CaF2 deposits on the membrane surface. In addition, a 300 hr continuous fluoride removal experiment of acidified groundwater was carried out with concentration factor at 4.0, the permeate flux kept stable and the permeate fluoride was not detected.