Problem Of Freshwater Scarcity Research Articles

Hierarchical structure design of sea urchin Shell-Based evaporator for efficient omnidirectional Solar-Driven steam generation

Solar-driven steam generation (SSG) is regarded as a feasible solution to the problem of fresh water scarcity. Although several attempts have been devoted to increase the efficiency of solar-to-steam conversion, it remains difficult to fabricate cost-effective, steady, and multi-angle sunlight-absorbing evaporators from readily available biomass materials. Herein, a novel hierarchical structured SSG evaporator (PDA@Shell-NaClO) is developed through a simple, low-cost, and scalable etching treatment on discarded sea urchin (SU) shells. Attributing to the dedicatedly designed microneedles array structure and porous skeleton structure of the SU shell, this PDA@Shell-NaClO evaporator shows an outstanding average light absorption performance (>90%) in a broad range of angles from 0° to 60° and exceedingly high evaporation rate of 2.81 kg m-2 h−1 under one sun condition. Furthermore, the prepared evaporator also maintains an overall stable evaporation performance and exhibits an excellent durability for a long time of up to two weeks in actual seawater. This full-ocean biomass-based SSG evaporator with plentiful raw material availability offers innovative opportunities for large-scale fresh water production.

Experimental investigation and performance evaluation of an oval tubular solar still with phase change material

The problem of freshwater scarcity is a major issue for people all over the world. Solar still is one of the most simplest and affordable ways to produce freshwater using solar energy which is available with no cost and eco-friendly. Recently, tubular solar stills (TSS) have gained popularity as one of the best solutions for acquiring pure water, especially in arid and coastal areas. The main objective of this paper is to enhance the productivity and efficiency of TSS by introducing a new form/shape, the oval tubular solar still (OTSS), integrated with cover cooling and phase change material (PCM). The OTSS is made of a transparent oval tube that is permeable to sunlight from all directions to maximize solar irradiance, and it is integrated with a black basin to improve absorption and water evaporation. It has an appropriate level of flexibility, durability, and low cost. Experiments were conducted out in the climatic conditions of Cairo, Egypt. This paper investigated different basin water depths and different water cover cooling flow rates to obtain their optimal values. Moreover, the effects of using PCM as a thermal management solution were studied in detail. In the case of no cooling, it is observed that the production rate decreases with increasing the water depth in the basin and the maximum production rate reached up to 5.21 L/m2/day at the optimal water depth of 0.5 cm. However, with cooling, the maximum production rate of 6.34 L/m2/day was achieved at the optimum water-cooling flow rate of 2 L/h. Using the PCM the maximum production rate of 6.78 L/m2/day was able to be achieved. The efficiency and productivity of the OTSS were enhanced by 41.26 % and 32.42 %, respectively, when using PCM. Furthermore, the daily thermal exergy efficiency of the OTSS was 3.46 %, 3.85 %, and 4.14 % for the cases no cooling, with cooling and with PCM, respectively. Economically, the cost per liter of desalinated water production was $0.020, $0.017, and $0.017 for the three cases, respectively.

Optimal water utilization and allocation in industrial sectors based on water footprint accounting in Dalian City, China

The problem of fresh water scarcity is one of the major constraints for regional development. Rapid urbanization and rising economic prosperity has further exacerbated problems with not only water quantity, but also water quality. Hence, sustainable utilization of water resources should be a priority, especially in water stressed areas. However, most current studies on optimal water allocation models are based on physical water, which cannot fully reveal the water flows embedded in imported and exported raw materials and products throughout all production processes. Thus, they fail to achieve sustainability goals. Therefore, the objective of this study was to set up an optimal water allocation model for industrial sectors based on water footprint accounting. In this paper, first the internal and external blue and gray water footprints were evaluated. The results indicated that the external water footprint was the major contributor to Dalian's water footprint, which shared around 72.58% of the total. Among all the industrial sectors, the chemical industry and chemical production sector had the highest total WF. Second, analyses of water productivity intensity of the WF and physical water for the industrial sectors were conducted. The comparison of the results revealed that physical water productivity intensity failed to explain the embedded water inflows in the production processes among the regions and sectors. Third, an optimization model based on the water footprint accounting results was thus set up. The optimal consequences indicated that a water allocation plan could meet both the water requirements for the blue and gray water footprints of the industrial sectors, and their target output goals as well. Therefore, this optimal allocation model is both rational and applicable for sustainable water utilization in future water management strategy formulations.

Community Based Sewage Treatment through Hybrid Constructed Wetlands System for Improved Heath & Hygiene and for Enhanced Agriculture Productivity / Livelihood Generation in Rural Water Scarce Environments-Pakistan

World over, fresh water scarcity problems are growing in scope & complexity to multiple factors, like population growth, climatic impacts, excessive water uses pattern in agriculture. A substantial quantum of treated wastewater , can be made available through constructed wetlands, which can supplement the fresh water scarcity. Almost, 80 % of the total generated raw sewage is being discharged into water bodies or being used for agriculture purposes, specially for vegetable farming, which contributes towards fresh water sources and food chain contamination. Centralized mechanical types of wastewater treatment plants are in use which is capital and recurring costs intensive. Resultantly, due to lack of sufficient recurring finances and energy shortages, these sewage treatment plants become non-operational and un-manageable. Moreover, huge centralized sewage treatment plants are difficult to manage due to longer chain of wastewater collection system and inflexibility of reuse of treated water in the areas of its generation. Therefore, keeping in view these obvious impediments, it was envisaged to plan & implement community based constructed wetlands system for sewage treatment, based on bio and phyto-remediation processes at village Chattal, district Chakwal (an arid area) which is functioning well and being sustained from selling the treated water to farmers and harvesting the various aquatic plants. Temporal analysis was carried out for verification of treatment system efficiency, whereby, monthly wastewater samples were collected at Inlet point (treated water reservoir) and got analyzed for Chemical Oxygen Demand (COD) and Biological Oxygen Demand (BOD) from PCRWR-Islamabad. Analysis report showed significant reduction of COD & BOD i.e. 86.1% & 91.4% respectively which are under permissible limits of Pak-EPA. Aesthetic value of treated water is remarkably improved after treatment as turbidity reduced from 15 NTU to 2 NTU. Detailed Health survey was carried out at village Chattal, to ascertain, the intervention efficiency. The result showed significant reduction in diarrheal & Hepatitis diseases i.e. 92.5% & 40% respectively and substantial improvements was observed in socio-economic, biodiversity and health & environment conditions of the rural population of village Chattal. Pakistan- the study area. This model will prove to be equally good in the rural environments of developing countries, especially in South Asia and Africa.

Liberal Approaches to the Study of Interconnection between Freshwater Scarcity and Security: Case Studies of India and Malaysia

Since 2004, with the new premierships of Manmohan Singh, in India, and Abdullah Badawi, in Malaysia, India and Malaysia have been playing active roles in decision-making on many issues, regionally through regional blocks. Despite these positive developments, the area where there is a pressing need for the two countries to discuss and act upon concerns environmental security, mainly freshwater scarcity and security. Both India and Malaysia face worrying proportions of freshwater shortages, due to a number of reasons, including increasing individual consumption, industrialisation and poor agricultural practices. This article discusses how both India and Malaysia, as well as their roles in four regional organisations, can recognise the problem of freshwater scarcity and security and propose solutions for adaptation and mitigation. The theoretical framework within which this discussion is couched in is liberalism.

Assessment of heavy metal contents of <i>Lycopersicum esculentum</i> mill. (tomato) and <i>Capsicum chinense l.</i> (pepper) irrigated with treated and untreated detergent and soap wastewaters

Tomato and pepper are staple and common vegetables consumed by all classes of Nigerian populace. Due to high consumption rate of these vegetables, they are cultivated all year round in many localities including the peri-urban cities. The problem of freshwater scarcity in peri-urbancities and the northern part of Nigeria has made peasant farmers in these areas to resolve to the use of wastewaters for irrigation with no knowledge of their status and safety. Therefore, the level of heavy metal contents in Lycopersicum esculentum and Capsicum chinense grown in the Screen House of the University of Ilorin, North-central Nigeria were studied using treated and untreated detergent and soap wastewaters. Fallowed soils collected from the University Botanical Garden, homogenized and packed into planting bags were used for the experiment. Viable seeds of Lycopersicum esculentum and Capsicum chinense were sown in 10 planting bags for each crop and irrigated with 0%, 5%, 10%, 20% and 40% Treated and Untreated wastewaters. After 12WAP, leaf samples of Lycopersicum esculentum and Capsicum chinense were collected, air-dried, digested and the digests were analyzed for Manganese (Mn), Copper (Cu), Chromium (Cr), Lead (Pb) and Cadmium (Cd) by Atomic Absorption  Spectrophotometry. It was evident that there was prevalence of heavy metals in the wastewaters particularly the untreated wastewater and the content of the heavy metals were concentration-dependent in theleaves of the test crops. It is therefore imperative to inform and enlighten the local farmers and the consumers on the danger of using such water for irrigation of agricultural crops in order to ensure safety.

INTERACTIVE EFFECT OF SOME DIFFERENT SEAWATER DILUTIONS, REMEDIATION TREATMENTS AT DIFFERENT GROWTH STAGES OF CELERY PLANTS ON: 1- VEGETATIVE GROWTH AND QUALITY PARAMETERS.

For facing acute problem of fresh water scarcity in the future, also, the sharing part from the Nile fresh water is 55.5 milliar m3. This amount cannot be increased. In turn, there is no an increase of the available water for cultivation of newly reclaimed lands or face increasing population So, two pot experiments were conducted in the open field of Agriculture Station, Mansoura University during the two successive winter seasons of 2006-2007 and 2007-2008. To evaluate the growth and quality characteristics of celery (Apium graveolens var dulce), cv. Victoria plants, in response to different seawater dilutions and some remediation treatments as well as salinization regime at different periods and their interactions. Factorial experiment in a randomized complete block design was used with 4 replicates for each treatment. The experiment included 90 treatments: 6 treatments of seawater dilutions with Nile water (Control, 5% seawater, 10% seawater, 15% seawater, 20% seawater, 25% seawater), 5 remediation treatments (without, Calcium 5mM (Ca1), Calcium 10 mM (Ca2), Polymer + Ca1, Polymer + Ca2). and 3 treatments of salinization regime ( after 20, 40, 60 days from transplanting). The results indicated that the effect of increasing the level seawater salinity from 5% up to 25% significantly decreased the mean values of plant growth parameters comparing with the control treatment (fresh water). Also, NO2-N and NO3-N concentrations were decreased significantly with increasing salinity levels. However, Vit C and TSS concentrations were increased significantly with increasing water salinity. Soil application with polymer combined with Ca2 was superior for increasing the most values of plant growth parameters, Vit C and TSS concentrations of celery plants following by foliar spraying with solution contains Ca (10 mM). While, both NO2-N and NO3-N decreased significantly with addition of remediation treatments. The lowest values were recorded with addition of calcium 10 mM. Also, All plant growth parameters, Vit C and TSS concentrations were significantly increased with decreasing salinization time (60, 40 and 20 days) after transplanting.The highest values were obtained when celery plants irrigated with saline water after 20 days from transplanting. On the other hand, NO2-N and NO3-N contents were increased significantly with increasing salinization time. The lowest values were recorded when plants received saline water after 20, following 40 and 60 days from transplanting. In addition, The highest tolerance to salinity effects (the best vegetative growth parameters) were obtained from the plants which irrigated with seawater dilution at 15% after 60 days from transplanting and treated with polymer + Ca, while the less tolerant plants were the plants which irrigated with seawater dilution after 20 days from transplanting. Also, data indicated that the highest values of Vit C and TSS concentrations were obtained under high salinity level (25% seawater) with addition of polymer + Ca2 and irrigation with saline water after 20 days from transplanting. Meanwhile, NO2-N and NO3-N contents were significantly decreased with increasing salinity levels, addition of remediation treatments and irrigation with saline water at early stage of plant growth (after 20 days from transplanting). Also, it reduces the free nitrate in plants of celery which is useful to the health of consumers. In general, it can be concluded that: 1- The highest tolerance to salinity with best quality was obtained from the plants which irrigated with seawater dilution at 15% (9 dS/m) after 60 days from transplanting and treated with polymer + Ca 10 mM under El-Dakahlia governorate conditions. 2- This treatment can be save about 10-150% of total water used to irrigation celery plants at different growth stages, consequently, it is considered one of ways for facing problem of fresh water scarcity in the future.