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The energy cost of water independence: the case of Singapore

Vincent L, Michel L, Catherine C, Pauline R

Water Sci Technol, 2014;70(5):787-94.
PMID: 25225924 DOI: 10.2166/wst.2014.290

Finding alternative resources to secure or increase water availability is a key issue in most urban areas. This makes the research of alternative and local water resources of increasing importance. In the context of political tension with its main water provider (Malaysia), Singapore has been implementing a comprehensive water policy for some decades, which relies on water demand management and local water resource mobilisation in order to reach water self-sufficiency by 2060. The production of water from alternative resources through seawater desalination or water reclamation implies energy consumptive technologies such as reverse osmosis. In the context of increasing energy costs and high primary energy dependency, this water self-sufficiency objective is likely to be an important challenge for Singapore. The aim of this paper is to quantify the long-term impact of Singapore's water policy on the national electricity bill and to investigate the impact of Singapore's projects to reduce its water energy footprint. We estimate that 2.0% of the Singaporean electricity demand is already dedicated to water and wastewater treatment processes. If its water-energy footprint dramatically increases in the coming decades, ambitious research projects may buffer the energy cost of water self-sufficiency.

Matched MeSH terms: Electricity
Constructed wetland integrated microbial fuel cell system: looking back, moving forward

Wang Y, Zhao Y, Xu L, Wang W, Doherty L, Tang C, et al.

Water Sci Technol, 2017 Jul;76(2):471-477.
PMID: 28726712 DOI: 10.2166/wst.2017.190

In the last 10 years, the microbial fuel cell (MFC) has been extensively studied worldwide to extract energy from wastewater via electricity generation. More recently, a merged technique of embedding MFC into a constructed wetland (CW) has been developed and appears to be increasingly investigated. The driving force to integrate these two technologies lies in the fact that CWs naturally possess a redox gradient (depending on flow direction and wetland depth), which is required by MFCs as anaerobic anode and aerobic cathode chambers. No doubt, the integration of MFC with a CW will upgrade the CW to allow it to be used for wastewater treatment and, simultaneously, electricity generation, making CWs more sustainable and environmentally friendly. Currently, published work shows that India, China, Ireland, Spain, Germany and Malaysia are involved in the development of this technology although it is in its infant stage and many technical issues are faced on system configuration, operation and maximisation of electricity production. This paper aims to provide an updated review and analysis of the CW-MFC development. Focuses are placed on the experience gained so far from different researchers in the literature and further research directions and proposals are discussed in great detail.

Matched MeSH terms: Electricity
Fulltext THE POTENTIAL OF SOLID ELECTROLYTE FROM FISH WASTE FOR BATTERY APPLICATION

Muhammad Ashraff Aiman Roslan, Nik Aziz Nik Ali

UMT Journal of Undergraduate Research, 2020;2(1):9-14.
MyJurnal

This experiment was conducted to study the potential of solid electrolyte from the fish waste of Clarias gariepinus for battery application. The battery was one of the important components that supplies electrical energy to users throughout the world, and it strongly contributed to technology development in the economic sector, transportation, residential as well as agriculture. The presence of ammonia in organic fish waste could produce renewable energy and helped to reduce the use of lithium-ion batteries in modern industries. Two different parameters were being observed in this study, which was the quantity of fish and the number of the cell layer. The process of collecting the fish waste was carried out in the hatchery at Universiti Malaysia Terengganu using two methods, which were filtering and soaking. The result showed that the highest value of energy output was 0.430V from waste filtering of 50 fish and 0.207V from soaking in waste of 50 fish. Meanwhile, the lowest energy output was from the tank that contained ten fish with an energy output of 0.177V for filtering and 0.101V for soaking. Besides, for a different number of the cell layer, the highest value of energy output was 0.414V at 25 layers, and the lowest voltage was 0.175V at five layers. Thus, from the study was observed that the produced voltage was dependent on the quantity of fish and the number of the cell layer, when the quantity of fish and number of cell layer increases, the output energy was also increased.

Matched MeSH terms: Electricity
PRODUCTION OF ENERGY FROM WATER FLOW OUTPUT IN FISH TANK

Muniandy Sivasambu, Nik Aziz Bin Nik Ali

UMT Journal of Undergraduate Research, 2020;2(1):21-30.
MyJurnal

Nowadays, the world is confronting the increasing energy demand, reduction of emissions and security of energy supply. The high energy demand leads to a severe problem, and we need to reduce the usage of non-renewable energy to avoid adverse climate change. Thus, renewable energy is an important role obtained from the natural environment and can be replenished naturally from those sources without environmental degradation. Water energy is one of the most promising renewable energy sources today, especially in the aquaculture industry. Hydropower played a vital role in producing large scale power and electricity. This study was set up to determine the electrical energy output depending on the different sizes and shapes of tanks. It is also to measure the water flow rate based on different size and shape tanks. Besides, the Pelton type of water turbine generator micro-hydroelectric DC 12V output was used in this experiment. Two types of tanks (rectangular and circular) with three different sizes (0.5 ton, 1.0 ton and 2.0 ton) were tested to measure high value of output energy (V) and flow rate (m3/s) by using clear water and wastewater. The result significantly shows that the circular tank had a higher water flow rate and output energy than the rectangular tank due to higher gravitational force, where the outlet placed in the middle and edge of the tank, respectively. The finding of this study benefits the aquaculture industry, where it introduced an alternative and cheaper method of reusing wastewater, reducing the cost maintenances and enhancing the profit of the business.

Matched MeSH terms: Electricity
Fulltext QSAR Studies on Neuraminidase Inhibitors as Anti-influenza Agents

Veerasamy R, Rajak H

Turk J Pharm Sci, 2021 04 20;18(2):151-156.
PMID: 33900700 DOI: 10.4274/tjps.galenos.2020.45556

Objectives: The present study aimed to establish significant and validated quantitative structure-activity relationship (QSAR) models for neuraminidase inhibitors and correlate their physicochemical, steric, and electrostatic properties with their anti-influenza activity.
Materials and Methods: We have developed and validated 2D and 3D QSAR models by using multiple linear regression, partial least square regression, and k-nearest neighbor-molecular field analysis methods.
Results: 2D QSAR models had q2: 0.950 and pred_r2: 0.877 and 3D QSAR models had q2: 0.899 and pred_r2: 0.957. These results showed that the models werere predictive.
Conclusion: Parameters such as hydrogen count and hydrophilicity were involved in 2D QSAR models. The 3D QSAR study revealed that steric and hydrophobic descriptors were negatively contributed to neuraminidase inhibitory activity. The results of this study could be used as platform for design of better anti-influenza drugs.

Matched MeSH terms: Static Electricity
Fulltext An overview of power electronics applications in fuel cell systems: DC and AC converters

Ali MS, Kamarudin SK, Masdar MS, Mohamed A

ScientificWorldJournal, 2014;2014:103709.
PMID: 25478581 DOI: 10.1155/2014/103709

Power electronics and fuel cell technologies play an important role in the field of renewable energy. The demand for fuel cells will increase as fuel cells become the main power source for portable applications. In this application, a high-efficiency converter is an essential requirement and a key parameter of the overall system. This is because the size, cost, efficiency, and reliability of the overall system for portable applications primarily depend on the converter. Therefore, the selection of an appropriate converter topology is an important and fundamental aspect of designing a fuel cell system for portable applications as the converter alone plays a major role in determining the overall performance of the system. This paper presents a review of power electronics applications in fuel cell systems, which include various topology combinations of DC converters and AC inverters and which are primarily used in fuel cell systems for portable or stand-alone applications. This paper also reviews the switching techniques used in power conditioning for fuel cell systems. Finally, this paper addresses the current problem encountered with DC converters and AC inverter.

Matched MeSH terms: Electricity
Fulltext Annual energy usage reduction and cost savings of a school: end-use energy analysis

Roslizar A, Alghoul MA, Bakhtyar B, Asim N, Sopian K

ScientificWorldJournal, 2014;2014:310539.
PMID: 25485294 DOI: 10.1155/2014/310539

Buildings are among the largest consumers of energy. Part of the energy is wasted due to the habits of users and equipment conditions. A solution to this problem is efficient energy usage. To this end, an energy audit can be conducted to assess the energy efficiency. This study aims to analyze the energy usage of a primary school and identify the potential energy reductions and cost savings. A preliminary audit was conducted, and several energy conservation measures were proposed. The energy conservation measures, with reference to the MS1525:2007 standard, were modelled to identify the potential energy reduction and cost savings. It was found that the school's usage of electricity exceeded its need, incurring an excess expenditure of RM 2947.42. From the lighting system alone, it was found that there is a potential energy reduction of 5489.06 kWh, which gives a cost saving of RM 2282.52 via the improvement of lighting system design and its operating hours. Overall, it was found that there is a potential energy reduction and cost saving of 20.7% when the energy conservation measures are earnestly implemented. The previous energy intensity of the school was found to be 50.6 kWh/m(2)/year, but can theoretically be reduced to 40.19 kWh/mm(2)/year.

Matched MeSH terms: Electricity
Fulltext Modeling of a high force density fishbone shaped electrostatic comb drive microactuator

Megat Hasnan MM, Mohd Sabri MF, Mohd Said S, Nik Ghazali NN

ScientificWorldJournal, 2014;2014:912683.
PMID: 25165751 DOI: 10.1155/2014/912683

This paper presents the design and evaluation of a high force density fishbone shaped electrostatic comb drive actuator. This comb drive actuator has a branched structure similar to a fishbone, which is intended to increase the capacitance of the electrodes and hence increase the electrostatic actuation force. Two-dimensional finite element analysis was used to simulate the motion of the fishbone shaped electrostatic comb drive actuator and compared against the performance of a straight sided electrostatic comb drive actuator. Performances of both designs are evaluated by comparison of displacement and electrostatic force. For both cases, the active area and the minimum gap distance between the two electrodes were constant. An active area of 800 × 300 μm, which contained 16 fingers of fishbone shaped actuators and 40 fingers of straight sided actuators, respectively, was used. Through simulation, improvement of drive force of the fishbone shaped electrostatic comb driver is approximately 485% higher than conventional electrostatic comb driver. These results indicate that the fishbone actuator design provides good potential for applications as high force density electrostatic microactuator in MEMS systems.

Matched MeSH terms: Static Electricity*
Fulltext Optimal battery sizing in photovoltaic based distributed generation using enhanced opposition-based firefly algorithm for voltage rise mitigation

Wong LA, Shareef H, Mohamed A, Ibrahim AA

ScientificWorldJournal, 2014;2014:752096.
PMID: 25054184 DOI: 10.1155/2014/752096

This paper presents the application of enhanced opposition-based firefly algorithm in obtaining the optimal battery energy storage systems (BESS) sizing in photovoltaic generation integrated radial distribution network in order to mitigate the voltage rise problem. Initially, the performance of the original firefly algorithm is enhanced by utilizing the opposition-based learning and introducing inertia weight. After evaluating the performance of the enhanced opposition-based firefly algorithm (EOFA) with fifteen benchmark functions, it is then adopted to determine the optimal size for BESS. Two optimization processes are conducted where the first optimization aims to obtain the optimal battery output power on hourly basis and the second optimization aims to obtain the optimal BESS capacity by considering the state of charge constraint of BESS. The effectiveness of the proposed method is validated by applying the algorithm to the 69-bus distribution system and by comparing the performance of EOFA with conventional firefly algorithm and gravitational search algorithm. Results show that EOFA has the best performance comparatively in terms of mitigating the voltage rise problem.

Matched MeSH terms: Electricity*
Fulltext Global renewable energy-based electricity generation and smart grid system for energy security

Islam MA, Hasanuzzaman M, Rahim NA, Nahar A, Hosenuzzaman M

ScientificWorldJournal, 2014;2014:197136.
PMID: 25243201 DOI: 10.1155/2014/197136

Energy is an indispensable factor for the economic growth and development of a country. Energy consumption is rapidly increasing worldwide. To fulfill this energy demand, alternative energy sources and efficient utilization are being explored. Various sources of renewable energy and their efficient utilization are comprehensively reviewed and presented in this paper. Also the trend in research and development for the technological advancement of energy utilization and smart grid system for future energy security is presented. Results show that renewable energy resources are becoming more prevalent as more electricity generation becomes necessary and could provide half of the total energy demands by 2050. To satisfy the future energy demand, the smart grid system can be used as an efficient system for energy security. The smart grid also delivers significant environmental benefits by conservation and renewable generation integration.

Matched MeSH terms: Electricity*
Fulltext Novel modulation method for multidirectional matrix converter

Toosi S, Misron N, Hanamoto T, Bin Aris I, Radzi MA, Yamada H

ScientificWorldJournal, 2014;2014:645734.
PMID: 25298969 DOI: 10.1155/2014/645734

This study presents a new modulation method for multidirectional matrix converter (MDMC), based on the direct duty ratio pulse width modulation (DDPWM). In this study, a new structure of MDMC has been proposed to control the power flow direction through the stand-alone battery based system and hybrid vehicle. The modulation method acts based on the average voltage over one switching period concept. Therefore, in order to determine the duty ratio for each switch, the instantaneous input voltages are captured and compared with triangular waveform continuously. By selecting the proper switching pattern and changing the slope of the carriers, the sinusoidal input current can be synthesized with high power factor and desired output voltage. The proposed system increases the discharging time of the battery by injecting the power to the system from the generator and battery at the same time. Thus, it makes the battery life longer and saves more energy. This paper also derived necessary equation for proposed modulation method as well as detail of analysis and modulation algorithm. The theoretical and modulation concepts presented have been verified in MATLAB simulation.

Matched MeSH terms: Electricity*
Fulltext Modeling, control, and simulation of battery storage photovoltaic-wave energy hybrid renewable power generation systems for island electrification in Malaysia

Samrat NH, Bin Ahmad N, Choudhury IA, Bin Taha Z

ScientificWorldJournal, 2014;2014:436376.
PMID: 24892049 DOI: 10.1155/2014/436376

Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions.

Matched MeSH terms: Electricity*
Fulltext Partial discharge characteristics of polymer nanocomposite materials in electrical insulation: a review of sample preparation techniques, analysis methods, potential applications, and future trends

Izzati WA, Arief YZ, Adzis Z, Shafanizam M

ScientificWorldJournal, 2014;2014:735070.
PMID: 24558326 DOI: 10.1155/2014/735070

Polymer nanocomposites have recently been attracting attention among researchers in electrical insulating applications from energy storage to power delivery. However, partial discharge has always been a predecessor to major faults and problems in this field. In addition, there is a lot more to explore, as neither the partial discharge characteristic in nanocomposites nor their electrical properties are clearly understood. By adding a small amount of weight percentage (wt%) of nanofillers, the physical, mechanical, and electrical properties of polymers can be greatly enhanced. For instance, nanofillers in nanocomposites such as silica (SiO2), alumina (Al2O3) and titania (TiO2) play a big role in providing a good approach to increasing the dielectric breakdown strength and partial discharge resistance of nanocomposites. Such polymer nanocomposites will be reviewed thoroughly in this paper, with the different experimental and analytical techniques used in previous studies. This paper also provides an academic review about partial discharge in polymer nanocomposites used as electrical insulating material from previous research, covering aspects of preparation, characteristics of the nanocomposite based on experimental works, application in power systems, methods and techniques of experiment and analysis, and future trends.

Matched MeSH terms: Electricity*
Fulltext A review on the fabrication of polymer-based thermoelectric materials and fabrication methods

Kamarudin MA, Sahamir SR, Datta RS, Long BD, Mohd Sabri MF, Mohd Said S

ScientificWorldJournal, 2013;2013:713640.
PMID: 24324378 DOI: 10.1155/2013/713640

Thermoelectricity, by converting heat energy directly into useable electricity, offers a promising technology to convert heat from solar energy and to recover waste heat from industrial sectors and automobile exhausts. In recent years, most of the efforts have been done on improving the thermoelectric efficiency using different approaches, that is, nanostructuring, doping, molecular rattling, and nanocomposite formation. The applications of thermoelectric polymers at low temperatures, especially conducting polymers, have shown various advantages such as easy and low cost of fabrication, light weight, and flexibility. In this review, we will focus on exploring new types of polymers and the effects of different structures, concentrations, and molecular weight on thermoelectric properties. Various strategies to improve the performance of thermoelectric materials will be discussed. In addition, a discussion on the fabrication of thermoelectric devices, especially suited to polymers, will also be given. Finally, we provide the challenge and the future of thermoelectric polymers, especially thermoelectric hybrid model.

Matched MeSH terms: Electricity*
Ultrafast Nonlinear Optical and Structure-Property Relationship Studies of Pyridine-Based Anthracene Chalcones Using Z-Scan, Degenerate Four-Wave Mixing, and Computational Approaches

Maidur SR, Patil PS, Katturi NK, Soma VR, Ai Wong Q, Quah CK

J Phys Chem B, 2021 Apr 22;125(15):3883-3898.
PMID: 33830758 DOI: 10.1021/acs.jpcb.1c01243

The structural, thermal, linear, and femtosecond third-order nonlinear optical (NLO) properties of two pyridine-based anthracene chalcones, (2E)-1-(anthracen-9-yl)-3-(pyridin-2-yl)prop-2-en-1-one (2PANC) and (2E)-1-(anthracen-9-yl)-3-(pyridin-3-yl)prop-2-en-1-one (3PANC), were investigated. These two chalcones were synthesized following the Claisen-Schmidt condensation method. Optically transparent single crystals were achieved using a slow evaporation solution growth technique. The presence of functional groups in these molecules was established by Fourier transform infrared and NMR spectroscopic data. The detailed solid-state structure of both chalcones was determined from the single-crystal X-ray diffraction data. Both crystals crystallized in the centrosymmetric triclinic space group P1̅ with the nuance of unit cell parameters. The crystals (labeled as 2PANC and 3PANC) have been found to be transparent optically [in the entire visible spectral region] and were found to be thermally stable up to 169 and 194 °C, respectively. The intermolecular interactions were investigated using the Hirshfeld surface analysis, and the band structures (highest occupied molecular orbital-lowest unoccupied molecular orbital, excited-state energies, global chemical reactivity descriptors, and molecular electrostatic potentials) were studied using density functional theory (DFT) techniques. The ultrafast third-order NLO properties were investigated using (a) Z-scan and (b) degenerate four-wave mixing (DFWM) techniques using ∼50 fs pulses at 800 nm (1 kHz, ∼4 mJ) from a Ti:sapphire laser amplifier. Two-photon-assisted reverse saturable absorption, self-focusing nonlinear refraction, optical limiting, and optical switching behaviors were witnessed from the Z-scan data. 3PANC demonstrated a stronger two-photon absorption coefficient, while 2PANC depicted a stronger nonlinear refractive index among the two. The time-resolved DFWM data demonstrated that the decay times of 2PANC and 3PANC were ∼162 and ∼180 fs, respectively. The second hyperpolarizability (γ) values determined by DFT, Z-scan, and DFWM were found to be in good correlation (with a magnitude of ∼10-34 esu). The ultrafast third-order NLO response, significant NLO properties, and thermal stability of these chalcones brands them as potential candidates for optical power limiting and switching applications.

Matched MeSH terms: Static Electricity
Pushing microbial desalination cells towards field application: Prevailing challenges, potential mitigation strategies, and future prospects

Salehmin MNI, Lim SS, Satar I, Daud WRW

Sci Total Environ, 2021 Mar 10;759:143485.
PMID: 33279184 DOI: 10.1016/j.scitotenv.2020.143485

Microbial desalination cells (MDCs) have been experimentally proven as a versatile bioelectrochemical system (BES). They have the potential to alleviate environmental pollution, reduce water scarcity and save energy and operational costs. However, MDCs alone are inadequate to realise a complete wastewater and desalination treatment at a high-efficiency performance. The assembly of identical MDC units that hydraulically and electrically connected can improve the performance better than standalone MDCs. In the same manner, the coupling of MDCs with other BES or conventional water reclamation technology has also exhibits a promising performance. However, the scaling-up effort has been slowly progressing, leading to a lack of knowledge for guiding MDC technology into practicality. Many challenges remain unsolved and should be mitigated before MDCs can be fully implemented in real applications. Here, we aim to provide a comprehensive chronological-based review that covers technological limitations and mitigation strategies, which have been developed for standalone MDCs. We extend our discussion on how assembled, coupled and scaled-up MDCs have improved in comparison with standalone and lab-scale MDC systems. This review also outlines the prevailing challenges and potential mitigation strategies for scaling-up based on large-scale specifications and evaluates the prospects of selected MDC systems to be integrated with conventional anaerobic digestion (AD) and reverse osmosis (RO). This review offers several recommendations to promote up-scaling studies guided by the pilot scale BES and existing water reclamation technologies.

Matched MeSH terms: Electricity
Renewable energy in Southeast Asia: Policies and recommendations

Erdiwansyah, Mamat R, Sani MSM, Sudhakar K

Sci Total Environ, 2019 Jun 20;670:1095-1102.
PMID: 31018425 DOI: 10.1016/j.scitotenv.2019.03.273

Southeast Asian countries stand at a crossroads concerning their shared energy future and heavily rely on fossil fuels for transport and electricity. Within Asia, especially India and China lead the world renewable energy generation undergoing a period of energy transition and economic transformation. Southeast Asian countries have huge potentials for sustainable energy sources. However they are yet to perform globally in renewable energy deployment due to various challenges. The primary objective of the study is to examine the renewable energy growth and analyse the government policies to scale up the deployment of renewables for power generation substantially. The study also offers policy recommendations to accelerate renewable energy exploitation sustainably across the region. To achieve the ambitious target of 23% renewables in the primary energy mix by 2025, ASEAN Governments should take proactive measures like removal of subsidies of fossil fuels, regional market integration and rapid implementation of the existing project. Eventually, each of this strategy will necessitate sustained leadership, political determination, and concrete actions from stakeholders, in particular, increased cooperation across the region.

Matched MeSH terms: Electricity
Fulltext Zinc removal and recovery from industrial wastewater with a microbial fuel cell: Experimental investigation and theoretical prediction

Lim SS, Fontmorin JM, Pham HT, Milner E, Abdul PM, Scott K, et al.

Sci Total Environ, 2021 Jul 01;776:145934.
PMID: 33647656 DOI: 10.1016/j.scitotenv.2021.145934

Microbial fuel cells (MFCs) that simultaneously remove organic contaminants and recovering metals provide a potential route for industry to adopt clean technologies. In this work, two goals were set: to study the feasibility of zinc removal from industrial effluents using MFCs and to understand the removal process by using reaction rate models. The removal of Zn2+ in MFC was over 96% for synthetic and industrial samples with initial Zn2+ concentrations less than 2.0 mM after 22 h of operation. However, only 83 and 42% of the zinc recovered from synthetic and industrial samples, respectively, was attached on the cathode surface of the MFCs. The results marked the domination of electroprecipitation rather than the electrodeposition process in the industrial samples. Energy dispersive X-ray (EDX) analysis showed that the recovered compound contained not only Zn but also O, evidence that Zn(OH)2 could be formed. The removal of Zn2+ in the MFC followed a mechanism where oxygen was reduced to hydroxide before reacting with Zn2+. Nernst equations and rate law expressions were derived to understand the mechanism and used to estimate the Zn2+ concentration and removal efficiency. The zero-, first- and second-order rate equations successfully fitted the data, predicted the final Zn2+ removal efficiency, and suggested that possible mechanistic reactions occurred in the electrolysis cell (direct reduction), MFC (O2 reduction), and control (chemisorption) modes. The half-life, t1/2, of the Zn2+ removal reaction using synthetic and industrial samples was estimated to be 7.0 and 2.7 h, respectively. The t1/2 values of the controls (without the power input from the MFC bioanode) were much slower and were recorded as 21.5 and 7.3 h for synthetic and industrial samples, respectively. The study suggests that MFCs can act as a sustainable and environmentally friendly technology for heavy metal removal without electrical energy input or the addition of chemicals.

Matched MeSH terms: Electricity
Upgrading a large and centralised municipal wastewater treatment plant with sequencing batch reactor technology for integrated nutrient removal and phosphorus recovery: Environmental and economic life cycle performance

Rashid SS, Liu YQ, Zhang C

Sci Total Environ, 2020 Dec 20;749:141465.
PMID: 32827824 DOI: 10.1016/j.scitotenv.2020.141465

Although nutrient removal and recovery from municipal wastewater are desirable to protect phosphorus resource and water-bodies from eutrophication, it is unclear how much environmental and economic benefits and burdens it might cause. This study evaluated the environmental and economic life cycle performance of three different upgraded Processes A, B and C with commercially available technologies for nutrient removal and phosphorus recovery based on an existing Malaysian wastewater treatment plant with a sequencing batch reactor technology and diluted municipal wastewater. It is found that the integration of nutrient removal, phosphorus recovery and electricity generation in all upgraded processes reduced eutrophication potential by 62-76%, and global warming potential by 7-22%, which, however, were gained at the cost of increases in human toxicity, acidification, abiotic depletion (fossil fuel) and freshwater ecotoxicity potentials by an average of 23%. New technologies for nutrient removal and phosphorus recovery are thus needed to achieve holistic rather than some environmental benefits at the expense of others. In addition, the study on two different functional units (FU), i.e. per m3 treated wastewater and per kg struvite recovered, shows that FU affected environmental assessment results, but the upgraded Process C had the least overall environmental burden with either of FUs, suggesting the necessity to use different functional units when comparing and selecting different technologies with two functions such as wastewater treatment and struvite production to confirm the best process configuration. The total life cycle costs of Processes A, B and C were 10.7%, 29.8% and 28.1%, respectively, higher than the existing process due to increased capital and operating costs. Therefore, a trade-off between environmental benefits and cost has to be balanced for technology selection or new integrated technologies have to be developed to achieve environmentally sustainable wastewater treatment economically.

Matched MeSH terms: Electricity
Fulltext Metal oxide based optical fiber for methane gas detection

Nor Akmar Mohd Yahya, Siti Azlida Ibrahim, Norizah Abdul Rahman, Mohd Adzir Mahdi, Mohd Hanif Yaacob

The Pertanika Journal of Scholarly Research Reviews, 2017;3(2):97-101.
MyJurnal

Semiconductor metal oxide (SMO) as a sensing layer for gas detection has been widely used. Many researches have been performed to enhance the sensing performance including its sensitivity, reliability and selectivity. Electrical sensors that use resistivity as an indicator of its sensing are popular and well established. However, the optical based sensor is still much to explore in detecting gas. By integrating it with SMO, the sensor offers good alternative to overcome some drawbacks from electrical sensors.

Matched MeSH terms: Electricity

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