Topic Review
Water Quality Index
A critical water quality index (WQI) method has been used to determine the overall water quality status of surface water and groundwater systems globally since the 1960s. WQI follows four steps: parameter selection, sub-indices, establishing weights, and final index aggregation.
  • 3175
  • 09 Apr 2021
Topic Review
Plasma technology water purification
Plasma technology water purification is a new water treatment technology developed according to the trend of industrial water use in the 21st century. It is effective, efficient, scalable, versatile and customizable. These technologies must be able to adapt to new contaminants, reduce energy consumption, maintain or improve the proportionality between power and flow, demonstrate various flow capacities, minimize the transformation of existing infrastructure, prepare for imminent regulations, and tailor chemistry to site-specific requirements. New methods of water treatment by plasma must have all the above-mentioned properties and pose the least risk to public health. NTAPPs and their chemical reactions release energy and reactive chemical species that can kill bacteria and microorganisms, resulting in the disinfection of water. The advantage of this technique is that it can be performed in ambient air under atmospheric pressure without a vacuum system. Furthermore, NTAPP does not involve chemical products such as Cl. NTAPP can be used for water treatment in three ways: via direct, indirect, and bubbling methods.
  • 1121
  • 10 Jun 2021
Topic Review
Water-Related Issues in Bhutan
Water for hydropower in Bhutan has been in focus as compared to that allocated for irrigation, industries, and environmental demand. The demand for water in Bhutan has also increased in the last decade due to population increase, changes in lifestyle, and economic advancements through tourism and hydropower projects.
  • 925
  • 28 Apr 2021
Topic Review
Photocatalytic Reactors Design
The photoreactors design and concepts vary based on the working regime (static or dynamic), photocatalyst morphology (powders or bulk) and volume.
  • 666
  • 10 May 2021
Topic Review
PEC Reactors for Water/Wastewater Treatment
Now and in the coming years, how we use and treat water, greywater and wastewater will become more important. A suitably designed photoelectrocatalytic (PEC) reactor is one potential solution. The photoexcitation of suitable semiconducting materials in aqueous environments can lead to the production of reactive oxygen species (ROS). ROS can inactivate microorganisms and degrade a range of chemical compounds. In the case of heterogeneous photocatalysis, semiconducting materials may suffer from fast recombination of electron–hole pairs and require post-treatment to separate the photocatalyst when a suspension system is used. To reduce recombination and improve the rate of degradation, an externally applied electrical bias can be used where the semiconducting material is immobilised onto an electrically conducive support and connected to a counter electrode. These electrochemically assisted photocatalytic systems have been termed “photoelectrocatalytic” (PEC). The term is stated in the IUPAC Recommendations 2011 as “electrochemically assisted photocatalysis. The role of the photocatalyst is played by a photoelectrode, often a semiconductor”. A short description of photocatalysis is included as it can be beneficial for those unfamiliar with the topic, before moving onto PEC. This entry is adapted from
  • 530
  • 20 Oct 2021
Topic Review
Water Quality and Life Expectancy
Since ancient times, the need for healthy water has resulted in the development of various kinds of water supply systems. From early history, civilizations have developed water purification devices and treatment methods. The necessity for fresh water has influenced individual lives as well as communities and societies.
  • 506
  • 25 Mar 2021
Topic Review
Addressing, Assessing and Improving Water Security
Water security is about managing too much, too little and/or too polluted water. Water security is about the increasing importance of sustainable management of water resources, drinking water and human well-being and protection of life and property from water-related disasters. Water security is about the health of ecosystems and economic development.  A groundwork of this broad and multi-faceted concept is presented to facilitate understanding, measuring and improving water security. 
  • 461
  • 25 Jan 2022
Topic Review
Membrane Fouling
Membrane-based separation has gained increased popularity over the past few decades, particularly reverse osmosis (RO). A major impediment to the improved performance of membrane separation processes, in general, is membrane fouling. Fouling has detrimental effects on the membrane’s performance and integrity, as the deposition and accumulation of foulants on its surface and/or within its pores leads to a decline in the permeate flux, deterioration of selectivity, and permeability, as well as a significantly reduced lifespan. Several factors influence the fouling-propensity of a membrane, such as surface morphology, roughness, hydrophobicity, and material of fabrication. Generally, fouling can be categorized into particulate, organic, inorganic, and biofouling. Efficient prediction techniques and diagnostics are integral for strategizing control, management, and mitigation interventions to minimize the damage of fouling occurrences in the membranes. To improve the antifouling characteristics of RO membranes, surface enhancements by different chemical and physical means have been extensively sought after. Moreover, research efforts have been directed towards synthesizing membranes using novel materials that would improve their antifouling performance. 
  • 303
  • 18 May 2021
Topic Review
Heat Recovery from Wastewater
Wastewater from domestic, industrial and commercial developments maintains considerable amounts of thermal energy after discharging into the sewer system. 
  • 301
  • 29 Jun 2021
Topic Review
Water Quality Degradation
Water quality degradation is happened through the natural processes that influence the surface water and groundwater quality by various sources such as climate changes, natural disasters, geological factors, soil-matrix, and hyporheic exchange. Water could also be contaminated by anthropogenic factors. Anthropogenic pollutants are substances caused by human actions, mostly resulting from land-use practices. 
  • 297
  • 05 Feb 2022
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