Performance evaluation of reverse osmosis (RO) pre-treatment technologies for in-land brackish water treatment

Integration of renewable energy with desalination technologies has emerged as an attractive solution to augment fresh water supply sustainably. Fouling and scaling are still considered as limiting factors in membrane desalination processes. For brackish water treatment, pre-treatment of reverse osmosis (RO) feed water is a key step in designing RO plants avoiding membrane fouling. This study aims to compare at pilot scale the rejection efficiency of RO membranes with multiple pre-treatment options at different water recoveries (30, 35, 40, 45 and 50%) and TDS concentrations (3500, 4000, and 4500mg/L). Synthetic brackish water was prepared and performance evaluation were carried out using brackish water reverse osmosis (BWRO) membranes (Filmtec LC-LE-4040 and Hydranautics CPA5-LD-4040) preceded by 5 and 1μm cartridge filters, 0.02μm ultra-filtration (UF) membrane, and forward osmosis (FO) membrane using 0.25M NaCl and MgCl2 as draw solutions (DS). It was revealed that FO membrane with 0.25M MgCl2 used as a draw solution (DS) and Ultra-filtration (UF) membrane followed by Filmtec membrane gave overall 98% rejection but UF facing high fouling potential due to high applied pressure. Use of 5 and 1μm cartridge filter prior to Filmtec membrane also showed effective results with 95% salt rejection

Oceanity and continentality climate indices in Pakistan

Conceptually, the influence of oceans and continents plays key roles in the climate of any region. This study considers continentality and oceanity thermal climate index and focuses on the synoptic classification of Pakistan. The country has a diversified geographic relief which has profound influence on its climate from region to region. While its more than 990 km long coastal belt has wetter maritime condition, its interior belt is under the influence of arid and semi arid conditions and its higher altitude region has a hyper-arid climate. Marsz, also called Kerner Oceanity and Conrad Continentality Indices were calculated for Pakistan using the country’s temperature annual range data of the past fifty years (1961-2010) at 51 climate stations. When correlations between the two continental indices are compared, it indicates that a large area of Pakistan has continental climate. This comparison may be beneficial for Pakistan’s energy reforms and agricultural sectors

Climate Change and Precipitation in Pakistan -A Meteorological Prospect

Pakistan has suffered prolonged periods of precipitation fluctuation that kept going on for decades. Shifting between such periods in northern and southern parts of the country often appears as a pace change. The object of this study is to assess prior changes in climatic patterns over various regions of Pakistan and the future magnitudinal changes of climate that would impact on water resources, which subsequently affect the ecosystem, health, food supply and country’s water resource sustainability. Trend and variability analysis have been applied on countrywide meteorological data for the period 1961-2010. The study revealed an increasing trend of 0.66oC in temperature and heavy and intense trend of 106 mm in precipitation during the past 110 years that has exacerbated food and water supply demand in the southern part of the country. This increasing heat of 0.06oC per decade speeds up the water cycle and evapo-transpiration processes. Atmospheric vapour pressure tendency has also demonstrated increasing trend of 0.96 mm per anum in water cycle. Extreme weather events resulting in droughts and floods reflect changes in climate. Pakistan has to combat water shortage by improving water reservoirs, regulating river water flow and adoption of other water conservation techniques to manage food and water supply – demand

Agricultural Productivity in Balochistan Province of Pakistan A Geographical Analysis

Agricultural sector plays a leading role in Pakistan’s economy. It contributed to nearly one fifth of the national GDP in 2010. Agricultural productivity is regions dependent, demanding further investigation. This study examines the productivity index in districts of Balochistan province of Pakistan from 1981-82 to 2008-2009. Besides the thermal and water regime, pedological conditions play a favorable role in growing of valuable crops. The food crops, wheat, rice, bajra, barley jowar and maize have been selected for the study. By contrast, very low level of agricultural productivity is confined to the districts falling in the drought prone areas characterized by irregular rainfall, rugged topography and poor irrigation facilities. Inadequacy of water is the main hurdle in agricultural productivity. For the present investigation, district wise secondary data have been collected from the agricultural census of Balochistan. The data collected have been processed and Yield Coefficient method has been employed to find out the level of agricultural productivity. The results are depicted by choropleth method on map. Hence, in the present paper an attempt has been made to assess the regional disparities in levels of agricultural productivity in districts of Balochistan province. Identification of causes of the disparity can prove helpful in solving the problem, thus enabling solution of food security

Agricultural Productivity in Balochistan Province of Pakistan A Geographical Analysis

Agricultural sector plays a leading role in Pakistan’s economy. It contributed to nearly one fifth of the national GDP in 2010. Agricultural productivity is regions dependent, demanding further investigation. This study examines the productivity index in districts of Balochistan province of Pakistan from 1981-82 to 2008-2009. Besides the thermal and water regime, pedological conditions play a favorable role in growing of valuable crops. The food crops, wheat, rice, bajra, barley jowar and maize have been selected for the study. By contrast, very low level of agricultural productivity is confined to the districts falling in the drought prone areas characterized by irregular rainfall, rugged topography and poor irrigation facilities. Inadequacy of water is the main hurdle in agricultural productivity. For the present investigation, district wise secondary data have been collected from the agricultural census of Balochistan. The data collected have been processed and Yield Coefficient method has been employed to find out the level of agricultural productivity. The results are depicted by choropleth method on map. Hence, in the present paper an attempt has been made to assess the regional disparities in levels of agricultural productivity in districts of Balochistan province. Identification of causes of the disparity can prove helpful in solving the problem, thus enabling solution of food security

Cognitive Dysfunction among U.S. High School Students and Its Association with Time Spent on Digital Devices: A Population-Based Study

Introduction: Cognitive dysfunction is a hallmark feature of many psychiatric disorders. We aimed to study the prevalence and predictors of cognitive dysfunction (CD) among U.S. high school students and its association with time spent on digital devices. Methods: We performed a cross-sectional survey study using YRBSS 2019 data of U.S. high school students in grades 9–12. Cognitive dysfunction was defined by difficulties with remembering, concentrating, and making decisions due to emotional, physical, or mental problems. Digital screen time was described by daily time spent on TV, computers, tablets, and phone. We performed univariate and multivariable survey logistic regression analysis to identify the prevalence of cognitive dysfunction and its association with time spent on digital devices. Results: Out of 10,317 total participants, 3914 (37.9%) reported CD. The prevalence of CD was higher in females compared to males (46.0% vs. 29.9%). Compared to participants with no CD, participants with CD reported substance abuse, such as alcohol (35.8% vs. 26.6%), marijuana (28.3% vs. 17.6%), cigarette (8.1% vs. 4.7%), and illicit drugs (18.9% vs. 9.0%) and they reported a higher prevalence (p p = 0.03) and ≥5 h (aOR:1.70; p < 0.0001) demonstrated higher odds of CD, compared to participants with no daily use. Female sex, substance use, and depressed mood were additional predictors of CD. Conclusion: The prevalence of CD is high in U.S. high-school students. Female sex, substance abuse, depressed mood, and excessive VG/PC use is associated with high odds of cognitive dysfunction. Further research is needed to explore the complex relationship between screen time and cognitive dysfunction