Papers by Keyword: Water Treatment

Abstract: This study utilizes phenanthrene as the model molecule to investigate the optimization and reusability of coal-derived carbon nanoparticles for the adsorption of polycyclic aromatic hydrocarbons (PAHs). After controlled carbonization and activation, the carbon nanoparticles were synthesized using a chemical solid synthesis method and meticulously studied to determine their surface morphology and crystallinity. One factor at a time (OFAT) was used as an optimization method for the batch adsorption studies, the parameters varied including pH, contact time, adsorbent dosage, Temperature, and initial phenanthrene concentration. The optimal circumstances for phenanthrene resulted in a high removal efficiency of up to 95.3% for phenanthrene, and 96% removal for naphthalene, hence demonstrating the material's potential for PAH remediation. Subsequent batch testing confirmed the material's efficacy in removing naphthalene and phenanthrene. Furthermore, reusability studies conducted over five adsorption-desorption cycles demonstrated minimal decline in removal efficiency for Naphthalene by 10%, with a difference between the 1^st and 5^th run. hence showing robust regeneration capability and operational stability. But it shows a high decline in removal efficiency for phenanthrene. The results demonstrate the efficacy and sustainability of coal-derived carbon nanoparticles as a cost-effective adsorbent for applications addressing PAH contamination in water.

Abstract: About a third of the world's population relies on groundwater for their water supply. However, in some cases, the quality of these sources is not suitable for human consumption. Reverse osmosis (RO) membrane technology is used in many cases to improve groundwater quality. Often, for effective performance of RO membranes pre-treatment of source water is required. This study aimed to assess the performance of the pre-treatment components of the brackish water RO desalination plants at the Grünau and Bethanie water supply areas. To assess the performance of the pre-treatment components at these two water supply areas, samples for water quality analyses like turbidity, fluoride, nitrate, and hardness were collected from the raw water and pre-treated water. The average removal efficiency of Bethanie’s sand filters was -2.14% for turbidity, hardness, nitrate, and fluoride. Sand filtration is a technology employed to reduce suspended solids (i.e. turbidity) and can improve microbiological quality. Sand filtration can also be used to remove precipitates formed after an oxidant was applied for example removal of iron and manganese. The negative value indicates that the sand filters were not effective in removing these contaminants, and in fact, they increased in concentration. The raw water was classified as group C, and the pre-treated water after sand filtration was group C as well. The average removal efficiency of Grünau’s sand filters was -43.28% for turbidity, hardness, nitrate, and fluoride. Again, this negative value indicates that the sand filters were not effective in removing these contaminants, and in fact, increased the concentrations. The raw water quality was classified as group D which remained as group D after sand filtration. The raw sources of water at both the treatment plants are groundwater abstracted from boreholes. This study demonstrated that the sand filters used in the pre-treatment at both plants provided minimal to no improvement in raw water quality and increased water losses through backwashing. Suspended solids and microbiological quality often do not require treatment with the use of groundwater, and therefore application of sand filtration technology as pre-treatment component not clearly justified. Therefore, future considerations regarding the use of these pre-treatment components in relation to raw water quality dynamics should be taken into account.

Abstract: It is common practice for cooling water systems in power plants to include a sludge tank to collect sludge and slurry. This research focuses on the development of a model that can be used as an aid in the design, operation, and modification of a settling tank, and the simulation of a sludge tank design in flow-through mode as a settling tank for suspended solids from cooling water systems. The purpose of this study is to investigate and understand the use of a sedimentation tank for cooling water system treatment to minimize SS through simulation. The research methodology was to determine, under laboratory conditions, the particle settling capacity and clarification performance in a settling tank: settling time, sedimentation rate, settleability, and productivity for a settling tank. The granulometric composition of the suspended solids was investigated to determine the circularity factor, the sphericity of the different types of particles, and the solidity of the suspended solids. Thus, the introduction of water treatment with a sedimentation tank with the geometric parameters used in this study will make it possible to remove up to 560m³ of suspended solids per quarter from the cooling water system.

Abstract: MXenes (Ti₃C₂) have gained significant research attention in the domain of photocatalysis due to their well-defined planar structure, exceptional metallic conductivity, diverse elemental content, terminations of surface groups and numerous derivatives. The utilization of MXene-derived and based materials serves as a compelling rationale for developing creative photocatalysts that exhibit both optimal activity and long-term stability. Titanium dioxide (TiO₂) has emerged as the most thoroughly researched photocatalyst due to its exceptional photocatalytic activity, affordability, lack of toxicity and abundant availability. However, TiO₂-based technologies are characterized by significant limitations, including a broadband gap and the rapid recombination of photoinduced charge carriers. Extensive research explores MXene's role in enhancing TiO₂ through MXene/TiO₂ nanocomposite synthesis. These nanocomposites enable efficient electron transport at the metal-semiconductor interface, with MXene serving as a co-catalyst or support to enhance catalytic activity. Traditional membrane separation techniques pose challenges, when efficiently removing contaminants as a result of fouling and pressure-related concerns. To address these constraints, novel membrane technologies, including photocatalytic membranes have been developed. By implementing these hybrid techniques the overdependence on size exclusion mechanisms can be bypassed, thereby enabling more effective separation of pollutants. This study addresses the recent advances in MXene/TiO₂-based photocatalytic membrane technology to eliminate new contaminants and improve pollutant removal when utilized with existing treatment methods.

Abstract: Water pollution poses a significant challenge to water consumption, particularly in relation to drinking purposes. Various factors such as industrial discharge, improper waste management, waste build-up, and natural activities contribute to the contamination of water bodies. Adequate water treatment plays a crucial role in the preservation of water quality and compliance with environmental regulations. The treatment process typically involves the application of physical, chemical, and biological techniques, with a common reliance on chemical substances and intricate systems. Recent studies have increasingly explored the utilization of cost-efficient natural materials for water treatment, highlighting benefits like affordability, user-friendliness, health advantages, and widespread availability. This particular investigation aimed to assess the suitability of selected natural substances for the treatment of wastewater, focusing primarily on methods like adsorption, absorption, and filtration. A number of earth materials, notably three distinct types of clays prevalent in Sri Lanka, were singled out for examination. The findings unveiled that these clays predominantly consist of over 75% iron in their mineral composition, with certain samples displaying finer particles to enhance porosity and permeability. These raw materials exhibit potential for the fabrication of wastewater treatment systems intended for the elimination of suspended particles, dissolved solids, heavy metals, pathogens, oils, and toxic compounds. Their distinct chemical properties render them appropriate for catalytic reactions and advanced chemical processes

Abstract: Abstract. Water is a natural and essential resource for life and must be preserved. Its potability is also vital for human survival. In this context, the turbidity parameter is a factor preponderant, as its presence can “protect” harmful microorganisms during the disinfection. Considering the extensive volume of data collected by Pelotas Autonomous Service of Sanitation at the Santa Bárbara Water Treatment Plant over the years, it was proposed to develop a methodology to support decision-making by managers, through data processing using statistical methods, machine learning and time series. Studies have shown that turbidity is an essential parameter in quality monitoring of the water andcan be inferred before the filtration stage from data collected throughout time. Furthermore, using data from the treatment plant itself offers the advantage of taking its peculiarities into account in the analysis.

Abstract: A vast amount of agricultural waste, such as dried leaves, stems, pits, seeds, etc., are produced by date palm trees in Saudi Arabia each year. This waste is an excellent source of degradable biomass suitable for many uses. Crystalline nanocellulose (CNC) is one of the most important nanomaterials that can be used in various applications. Due to its unique properties, which include biorenewability, optical transparency, high mechanical strengths, and sustainability, nanocrystalline cellulose has become a significant nanomaterial in recent years. In this study, CNC was isolated from the waste date palm leaves and used for the production of PA-modified membranes for water treatment by reverse osmosis membrane technology. The membranes were prepared by surface polymerization with the polyamide as a selective layer on the polysulfone support film. Three membranes were produced, two with 0.01% and 0.02% (w/v) CNC and the third with PA-free CNC for comparison. Each membrane produced was tested using different characterization techniques. The polyamide membrane with 0.01% w/v CNC had a higher water permeability of 43.25 L/m² h bar than the membranes with 0% w/v CNC (36.25 L/m² h) and 0.02% w/v CNC (42.85 L/m² h bar). Under the same conditions, salt retention was also found to be above 98% for both NaCl and MgSO4 for the two modified membranes. The contact angle was found to be 68.04±3.7, 72.83±0.8, and 63.76±5.5 for PA(0%CNC), PA-CNC (0.01% w/v), and PA-CNC (0.02% w/v), respectively. The 0.01% PA-CNC membrane exhibited a higher water contact angle, greater hydrophobicity and lower surface roughness. As a result, the isolated CNC might be appropriate for use as a modifier agent for membrane fabrication and water treatment.

Abstract: This work deals with an adaptable water reactor design built from different modules as a basis for research. These modules are selected according to the application and are used for sensor related cleaning and supporting tasks. For example, to produce a specific water quality or for pharmaceutical applications. Sensor related modules are used to measure various parameters such as temperature, TOC, flow parameters and others. In addition to simple membrane filter modules, UV-C disinfection and experimental modules are integrated into the setup. Modules for pumping processes, for power supply such as solar, for control tasks and the connection systems of water and electricity between modules are also outlined. This system is described on the basis of scientific examples that use this system. In more detail the modules for temperature, TOC measurement, and UV-C disinfection as well as the supply and control modules are shown.

Abstract: The scarcity of drinking water is currently a critical issue in many parts of the world. Providing clean/urgent longer limited to natural sources. Wastewater treatment has become an urgent necessity in many countries, particularly in the Middle East and North African regions characterized by a desert climate. Hence, the development of effective methods for wastewater treatment is vital to overcome this water shortage. The present study attempts to explore the use of local clay from the United Arab Emirates (UAE) to prepare porous ceramic membranes (flat disk shape) for the purpose of removing toxic heavy metals from contaminated water. Two types of ceramic membranes were prepared by powder metallurgy method; the first type was prepared by uniaxial compression of the clay powder with particle size ≤ 250 μm, followed by sintering. The second type of membrane was composed of an activated carbon/clay powder mixture at different ratios (0.5%, 3% w/w). The activated carbon was used as an agent to form porosity in the plain clay membrane. The activated carbon was found to affect the final characteristics of the flat disk membranes sintered at 1000°C. 3% w/w activated carbon/clay powder was found to induce 19% porosity in the flat disc. The flat disc membranes were also characterized by X-ray diffraction, and scanning electron microscopy, X-ray fluorescence. The plain clay and 3% w/w activated carbon membranes were tested for their efficiency for water permeation. The results proved that the UAE clay could be considered as a promising material for the fabrication of ceramic membranes for prospective use in the removal of water contaminated with heavy metals.

Abstract: This study aims to overcome decreasing cooling tower efficiency at Geothermal Power Plant Kamojang Unit 1. Based on visual observations, there has been a tendency to blockage in the cooling tower's film fill and nozzle areas by mud, sulphate, scale, biofouling, moss, and other impurities. As a coolant, the water quality from the cold basin cooling tower has an essential role in determining the cooling tower performance. Preliminary test results show that cold water from the basin cooling tower contains high sulfate ions and bacteria than typical values. For this purpose, laboratory-scale demineralization with ion exchange is designed for sulfate ion treatment and sodium hypochlorite injection to reduce the bacterial height and validate the treatment, heat transfer, and cooling tower efficiency calculations before and after treatment. The results showed that with demineralization, sulfate levels from 224 ppm to < 5 ppm, and sodium hypochlorite injection, the optimum injection concentration was 2 ppm, from 19000 CFU/ml, it could reduce bacteria to 100CFU/ml. Finally, the improvement in cooling tower efficiency before and after treatment was 17.36%.