Utilization Of Freshwater Resources Research Articles

Application of UF and RO for power plant's wastewater treatment and recycling for environmental sustainability

Abstract Global indicators have warned of freshwater scarcity in Asia. However, the utilization of freshwater resources has skyrocketed for commercial and industrial purposes without any strategy for recycling and reuse. The power plant's wastewater/reject mainly consisted of cooling tower blowdown water and reverse osmosis (RO) plant reject water. Due to the high turbid nature of reject water, pretreatment was carried out to achieve SDI15 <3 by employing multimedia filters (MMF), activated carbon filters (ACF) and ultrafiltration (UF). Operational parameters of RO membranes were optimized (11.5 bar, 29 °C) to achieve maximum water recovery along with higher rejection rates of critical scale forming species such as 81% total dissolved solids (TDS), 73% calcium hardness and 72% silica (Si). After accounting for backwash water and other concentrate rejections, the membrane treatment plant has achieved an appreciable recovery rate of more than 44%. The RO membrane-treated water was then incorporated in the cooling tower and a 16% reduction in freshwater makeup was achieved. Reduction of microbial growth rate as well as corrosion and scaling in the cooling tower was observed due to the reuse of treated water. This is to confirm here that brackish water RO membranes can act as a strong contender for reject water reclamation and effective utilization.

Contamination Transport in the Coastal Unconfined Aquifer under the Influences of Seawater Intrusion and Inland Freshwater Recharge-Laboratory Experiments and Numerical Simulations.

The coupled effect of seawater intrusion and inland freshwater recharge plays an important role in contamination transport in coastal heterogeneous aquifer. In this study, the effects of seawater intrusion and inland recharge on contamination transport were investigated by conducting laboratory experiments and numerical simulations. The laboratory tests were conducted in a sand tank considering two scenarios, namely the conditions of landward and seaward hydraulic gradients. The SEAWAT software was applied for validating the contaminant transport in coastal heterogeneous aquifer. The results indicated that the simulated seawater wedge and contours of the saltwater contaminant matched the observed ones well. The length of the seawater wedge in the scenario of seaward hydraulic gradient was smaller than that in the scenario of landward hydraulic gradient, which reflected that the large quantity of inland recharge have a negative effect on the invasion process of seawater. The plume moved mainly downward in the heterogeneous unconfined aquifer for both scenarios. The pollution plume became concave at the interface between each two layers, which was because the velocity of contaminant plume migration increased gradually from the upper layer to lower layer. The migration direction of the front of the plume was consistent with the direction of hydraulic gradient, which indicated that it was influenced by the water flowing. The maximum area of plume in the scenario of seaward hydraulic gradient was slightly smaller than that in the scenario of landward hydraulic gradient. The maximum area and vertical depth of the pollutant plume were sensitive to the hydraulic conductivity, dispersivity and contamination concentration. This study was of great significance to the controlling of pollution and utilization of freshwater resources in coastal areas.

The Impact of a Human Right to Water on the Sustainable Balance of Water Uses under the UN Watercourses Convention

This article sets the global scene for the regional and local levels elaborated upon by articles later in this special issue by addressing the following research question: What is the impact of a human right to water on the sustainable balance of water uses under the customary international water law principle of equitable and reasonable utilization as codified in the UN Watercourses Convention? In order to answer this question, first, both a human right to water and vital human needs are introduced. Second, the position of a human right to water under the UN Watercourses Convention is reviewed, focusing on vital human needs that require special regard in order to reach equitable and reasonable utilization of freshwater resources. Third, various water uses to be taken into account when aiming for a sustainable balance are considered. Finally, the shift in balance by the coming into existence of a human right to water is concluded upon: It is argued that the impact of the human right to water results in effective priority of water uses for vital human needs in the application of the principle of equitable and reasonable utilization of international watercourses, reinforcing the human right to water beyond borders in return. This article contributes to the legal discourse by linking the general principles of international water law to the human right to water, which are foremost dealt with separately in existing literature, and clarifies the position of this right in the balance of water uses in cases of transboundary water allocation.

NANOTECHNOLOGY IN THE FUNCTION OF SUSTAINABLE WATER USE

Nanotechnology, as contemporary field of research in forming of materials and devices on the level of molecule and atoms, is founding broad utilization in different scientific and engineering domains. The influence of nanotechnology on the development of contemporary human society has got a significant potential in domains as economy, environment protection, health and improvement of the quality of life. The need for fresh water as a necessary resource for living world, as well as the economic activity on the level of humanity is growing in the conditions of increasing population, increasing economic activities and increasing pollution. In that sense the conventional methods for water treatment may become ineffective for providing sustainable utilization of water resources in the future. Nanotechnology as a contemporary scientific and engineering field is considered efficient and potentially, the only solution for sustainable utilization of fresh water in the future. The efforts in nanotechnology utilization for sustainability of fresh water resources mean comprehensive approach and clarity in defining goals as well as the ways for their realization. The basic expectations of nanotechnology in the sense of fresh water resources utilization are directed to enhancement of fresh water availability, increase of efficiency of fresh water delivery and enabling next generation systems for fresh water quality monitoring. The increase of fresh water availability by nanotechnology means development of filtering systems and development of membrane systems, inverse osmosis for water desalinization and catalysts for water treatment. Efficiency of fresh water delivery based on nanotechnology means reducing energy necessary for its transportation, developing system of pipes and components which are easier, stronger and which will last longer as well as to provide cheap materials which improve energy efficiency for heating and cooling. All these processes for nanotechnology development aiming to provide sustainable fresh water resources utilization require significant efforts on scientific and engineering level in order to be utilized in everyday life. This paper aims to research the state of the art of nanotechnology development in the domain of sustainable utilization of fresh water resources.

Water Governance and Water Management Systems in the Tekeze River Basin

The fact that a lot of fresh water resources in Ethiopia are shared between several sovereign states creates a difficult situation in terms of water governance and management. Since there is no central agency that can regulate the utilization of water, the autonomous riparian actors pursue their respective interests. Water is shared at local, national and international levels; and difficulty in water supply management arises from lack of coordination between local, national and international authorities. Most of the Ethiopian rivers are trans-boundary, i.e. shared by several sovereign states. The purpose of this paper is to examine water governance and management systems in the Tekeze River basin. The author uses the qualitative research method to critically examine the existing scarce literature sources and governmental policy documents. The findings of the study revealed the absence of any kinds of bilateral agreements among the riparian states of the Tekeze River basin. As the water governance system in the region is highly politicized, there exists a certain clash of interests between the Tekeze River nations. The constant conflict in the region disrupts cooperation needed for facility maintenance in the Tekeze River basin. The problems in the area arise due to the following factors: no demarcated boundaries between the basin states; no effective water governance system, and, as a result, no efficient and cooperative utilization of fresh water resources; lack of institutional and legal arrangements between the major riparian states.