Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
1.
J Environ Manage ; 360: 121138, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38749131

RESUMO

In the pursuit of alternatives for conventional diesel, sourced from non-renewable fossil fuel, biodiesel has gained attentions for its intrinsic benefits. However, the commercial production process for biodiesel is still not sufficiently competitive. This review analyses microalgal lipid, one of the important sources of biodiesel, and its cultivation techniques with recent developments in the technical aspects. In fact, the microalgal lipids are the third generation feedstock, used for biodiesel production after its benefits outweigh that of edible vegetable oils (first generation) and non-edible oils (second generation). The critical factors influencing microalgal growth and its lipid production and accumulation are also discussed. Following that is the internal enhancement for cellular lipid production through genetic engineering. Moreover, the microalgae cultivation data modelling was also rationalized, with a specific focus on growth kinetic models that allow for the prediction and optimization of lipid production. Finally, the machine learning and environmental impact analysis are as well presented as important aspects to consider in fulfilling the prime objective of commercial sustainability to produce microalgal biodiesel.


Assuntos
Biocombustíveis , Lipídeos , Microalgas , Microalgas/metabolismo , Microalgas/crescimento & desenvolvimento , Lipídeos/química
2.
J Environ Manage ; 320: 115750, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35933874

RESUMO

Palm oil is the most utilized vegetable globally which is mostly produced in countries such as Malaysia, Indonesia and Thailand. The great amount of POME generation from palm oil mills is now a threat to the environment and require a suitable treatment of POME to reduce the organic strength in accordance with the standard discharge limit before releasing to the environment. Currently, the technology to combine the anaerobic process and biofilm system in bioreactors have produced a fresh idea in treatments of high strength wastewater like POME. Anaerobic biofilm reactor is a convincing method for POME treatment due to its significant advantages over the conventional biological treatments consisting of anaerobic, aerobic and facultative pond systems. Overall, integrated anaerobic-aerobic bioreactor (IAAB) can remove more than 99% of chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) with the combination of anaerobic and aerobic digestion for POME treatment. It has better performance as compared to up-flow anaerobic sludge blanket (UASB) and up-flow anaerobic filter (UAF) with 80% and 88-94% COD removal efficiency respectively. Anaerobic pond was found to perform well also by removing 97.8% of COD in POME but require long retention time and larger land. Hence, this study aims to provide intensive review of the performance of the anaerobic biofilm reactor in treating POME and the recent advancements in this technology. The limitations and future perspectives in utilization of anaerobic biofilm reactor during its operation in treating POME are discussed.


Assuntos
Reatores Biológicos , Óleos de Plantas , Anaerobiose , Biofilmes , Resíduos Industriais , Óleo de Palmeira , Eliminação de Resíduos Líquidos/métodos
3.
J Environ Manage ; 324: 116415, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36206653

RESUMO

Remediation by algae is a very effective strategy for avoiding the use of costly, environmentally harmful chemicals in wastewater treatment. Recently, industries based on biomass, especially the bioenergy sector, are getting increasing attention due to their environmental acceptability. However, their practical application is still limited due to the growing cost of raw materials such as algal biomass, harvesting and processing limitations. Potential use of algal biomass includes nutrients recovery, heavy metals removal, COD, BOD, coliforms, and other disease-causing pathogens reduction and production of bioenergy and valuable products. However, the production of algal biomass using the variable composition of different wastewater streams as a source of growing medium and the application of treated water for subsequent use in agriculture for irrigation has remained a challenging task. The present review highlights and discusses the potential role of algae in removing beneficial nutrients from different wastewater streams with complex chemical compositions as a biorefinery concept and subsequent use of produced algal biomass for bioenergy and bioactive compounds. Moreover, challenges in producing algal biomass using various wastewater streams and ways to alleviate the stress caused by the toxic and high concentrations of nutrients in the wastewater stream have been discussed in detail. The technology will be economically feasible and publicly accepted by reducing the cost of algal biomass production and reducing the loaded or attached concentration of micropollutants and pathogenic microorganisms. Algal strain improvement, consortium development, biofilm formation, building an advanced cultivation reactor system, biorefinery concept development, and life-cycle assessment are all possible options for attaining a sustainable solution for sustainable biofuel production. Furthermore, producing valuable compounds, including pharmaceutical, nutraceutical and pigment contents generated from algal biomass during biofuel production, could also help reduce the cost of wastewater management by microalgae.


Assuntos
Biocombustíveis , Microalgas , Águas Residuárias , Biodegradação Ambiental , Biomassa
4.
Environ Res ; 185: 109458, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32247911

RESUMO

The conventional practice in enhancing the larvae growths is by co-digesting the low-cost organic wastes with palatable feeds for black soldier fly larvae (BSFL). In circumventing the co-digestion practice, this study focused the employment of exo-microbes in a form of bacterial consortium powder to modify coconut endosperm waste (CEW) via fermentation process in enhancing the palatability of BSFL to accumulate more larval lipid and protein. Accordingly, the optimum fermentation condition was attained by inoculating 0.5 wt% of bacterial consortium powder into CEW for 14-21 days. The peaks of BSFL biomass gained and growth rate were initially attained whilst feeding the BSFL with optimum fermented CEW. These were primarily attributed by the lowest energy loss via metabolic cost, i.e., as high as 22% of ingested optimum fermented CEW was effectively bioconverted into BSFL biomass. The harvested BSFL biomass was then found containing about 40 wt% of lipid, yielding 98% of fatty acid methyl esters of biodiesel upon transesterification. Subsequently, the protein content was also analyzed to be 0.32 mg, measured from 20 harvested BSFL with a corrected-chitin of approximately 8%. Moreover, the waste reduction index which represents the BSFL valorization potentiality was recorded at 0.31 g/day 20 BSFL. The benefit of fermenting CEW was lastly unveiled, accentuating the presence of surplus acid-producing bacteria. Thus, it was propounded the carbohydrates in CEW were rapidly hydrolysed during fermentation, releasing substantial organic acids and other nutrients to incite the BSFL assimilation into lipid for biodiesel and protein productions simultaneously.


Assuntos
Dípteros , Simuliidae , Animais , Biocombustíveis , Cocos , Endosperma , Larva
5.
J Environ Manage ; 248: 109302, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31377539

RESUMO

Palm oil sludge (POS) is an organic waste generated from the palm oil industry. POS causes environmental pollution if it is improperly disposed. In this study, the potential of activated POS biochar, as an adsorbent for the removal of SO2 gas was tested. POS biochar was physically activated using CO2 gas. The effects of activation preparation variables i.e. activation temperature (300-700 °C), activation time (30-150 min) and CO2 flow rate (100-500 ml/min) were investigated using design expert version 8.0.7.1 software. Central Composite Design (CCD) was used to develop a quadratic model to correlate the operating variables with the activated biochar adsorption capacity. Analysis of variance (ANOVA) was performed to identify the significant factors on the experimental design response. The optimum preparation conditions of activated POS biochar were found to be at activation temperature of 442 °C, activation time of 63 min and CO2 flow rate of 397 ml/min. The maximum adsorption capacity at the optimum conditions was recorded as 16.65 mg/g. The adsorption capacity increased significantly after the activation process. Characteristics of the activated POS biochar proposed that SO2 was physically adsorbed. Furthermore, it was found that the adsorption capacity can be further enhanced by increasing the reaction temperature to 100 °C or with 15% of relative humidity in the inlet gas. The prepared adsorbents can be regenerated by thermal treatment.


Assuntos
Esgotos , Dióxido de Enxofre , Adsorção , Carvão Vegetal , Óleo de Palmeira
6.
Water Sci Technol ; 79(10): 1860-1867, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31294702

RESUMO

The application of the anammox process has great potential in treating nitrogen-rich wastewater. The presence of Fe (II) is expected to affect the growth and activity of anammox bacteria. Short-term (acute) and long-term effects (chronic) of Fe (II) on anammox activity were investigated. In the short-term study, results demonstrated that the optimum concentration of Fe (II) that could be added to anammox is 0.08 mM, at which specific anammox activity (SAA) improved by 60% compared to the control assay, 0.00 mM. The inhibition concentration, IC50, of Fe (II) was found to be 0.192 mM. Kinetics of anammox specific growth rate were estimated based on results of the batch test and evaluated with Han-Levenspiel's substrate inhibition kinetics model. The optimum concentration and IC50 of Fe (II) predicted by the Han-Levenspiel model was similar to the batch test, with values of 0.07 mM and 0.20 mM, respectively. The long-term effect of Fe (II) on the performance of a sequencing batch reactor (SBR) was evaluated. Results showed that an appropriate Fe (II) addition enhanced anammox activity, achieving 85% NH4 +-N and 96% NO2 --N removal efficiency when 0.08 mM of Fe (II) was added. Quantitative polymerase chain reaction (qPCR) was adopted to detect and identify the anammox bacteria.


Assuntos
Compostos de Amônio , Anaerobiose , Ferro/química , Reatores Biológicos , Oxirredução , Águas Residuárias
7.
J Environ Manage ; 205: 244-252, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-28987987

RESUMO

The increase in landfill leachate generation is due to the increase of municipal solid waste (MSW) as global development continues. Landfill leachate has constantly been the most challenging issue in MSW management as it contains high amount of organic and inorganic compounds that might cause pollution to water resources. Biologically treated landfill leachate often fails to fulfill the regulatory discharge standards. Thus, to prevent environmental pollution, many landfill leachate treatment plants involve multiple stages treatment process. The Papan Landfill in Perak, Malaysia currently has no proper leachate treatment system. In the current study, sequential treatment via sequencing batch reactor (SBR) followed by coagulation was used to treat chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), total suspended solids (TSS), and colour from raw landfill leachate. SBR optimum aeration rate, L/min, optimal pH and dosage (g/L) of Alum for coagulation as a post-treatment were determined. The two-step sequential treatment by SBR followed by coagulation (Alum) achieved a removal efficiency of 84.89%, 94.25%, 91.82% and 85.81% for COD, NH3-N, TSS and colour, respectively. Moreover, the two-stage treatment process achieved 95.0% 95.0%, 95.3%, 100.0%, 87.2%, 62.9%, 50.0%, 41.3%, 41.2, 34.8, and 22.9 removals of Cadmium, Lead, Copper, Selenium, Barium, Iron, Silver, Nickel, Zinc, Arsenic, and Manganese, respectively.


Assuntos
Reatores Biológicos , Eliminação de Resíduos , Poluentes Químicos da Água , Análise da Demanda Biológica de Oxigênio , Ferro , Malásia , Nitrogênio
8.
J Environ Manage ; 193: 458-469, 2017 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-28262420

RESUMO

Malaysia alone produces more than 49 million m3 palm oil mill effluent per year. Biological treated palm oil mill effluent via ponding system often fails to fulfill the regulatory discharge standards. This is due to remaining of non-biodegradable organics in the treated effluent. Thus, the aim of this study was to resolve such issue by using electro persulphate oxidation process, for the first time, as a post treatment of palm oil mill effluent. Central composite design in response surface methodology was used to analyze and optimize the interaction of operational variables (i.e., current density, contact time, initial pH and persulphate dosage) targeted on maximum treatment efficiency. The significance of quadratic model of each response was determined by analysis of variance, where all models indicated sufficient significance with p-value < 0.0001. Optimum operational conditions with 45 mA/cm2 of current density, 45 min of contact time, pH 4 and 0.892 g of S2O82- proved that 77.70% of Chemical Oxygen Demand, 97.96% of colour as well as 99.72% of Suspended Solids removal were achieved. The final pH of 5.88 of the effluent was obtained that fulfilled the limit and suitable for direct discharge to the natural environment.


Assuntos
Resíduos Industriais , Eliminação de Resíduos Líquidos , Análise da Demanda Biológica de Oxigênio , Modelos Teóricos , Óleos de Plantas , Lagoas
9.
Water Sci Technol ; 76(5-6): 1389-1398, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28953465

RESUMO

Three different sizes of powdered activated carbon (PAC) were added in hybrid anaerobic membrane bioreactors (AnMBRs) and their performance was compared with a conventional AnMBR without PAC in treating palm oil mill effluent. Their working volume was 1 L each. From the result, AnMBRs with PAC performed better than the AnMBR without PAC. It was also found that adding a relatively smaller size of PAC (approximately 100 µm) enhanced the chemical oxygen demand removal efficiency to 78.53 ± 0.66%, while the concentration of mixed liquor suspended solid and mixed liquor volatile suspended solid were 8,050 and 6,850 mg/L, respectively. The smaller size of PAC could also enhance the biofloc formation and biogas production. In addition, the smaller particle sizes of PAC incorporated into polyethersulfone membrane resulted in higher performance of membrane fouling control and produced better quality of effluent as compared to the membrane without the addition of PAC.


Assuntos
Biocombustíveis , Reatores Biológicos , Resíduos Industriais , Membranas Artificiais , Óleo de Palmeira/química , Anaerobiose , Análise da Demanda Biológica de Oxigênio , Carvão Vegetal , Poluentes Químicos da Água/química
10.
Water Sci Technol ; 74(11): 2675-2682, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27973372

RESUMO

The aim of the current study is to evaluate the effectiveness of combined persulphate with hydrogen peroxide (S2O82-/H2O2) oxidation as a post-treatment of biologically treated palm oil mill effluent (POME) for the first time in the literature. The removal efficiencies of chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), and suspended solids (SS) were 36.8%, 47.6%, and 90.6%, respectively, by S2O82- oxidation alone under certain operation conditions (i.e., S2O82- = 0.82 g, pH 11, and contact time 20 min). Nevertheless, the combined process (S2O82-/H2O2) achieved 75.8% and 87.1% removals of NH3-N and SS, respectively, under 2.45/1.63 g/g H2O2/S2O82-, pH 11, and 20 min oxidation. Moreover, 56.9% of COD was removed at pH 8.4.


Assuntos
Peróxido de Hidrogênio/química , Resíduos Industriais , Óleos de Plantas , Compostos de Sódio/química , Sulfatos/química , Poluentes Químicos da Água/química , Análise da Demanda Biológica de Oxigênio , Oxirredução , Óleo de Palmeira , Eliminação de Resíduos Líquidos/métodos
11.
Water Sci Technol ; 73(11): 2704-12, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27232407

RESUMO

As the ponding system used to treat palm oil mill effluent (POME) frequently fails to satisfy the discharge standard in Malaysia, the present study aimed to resolve this problem using an optimized electrocoagulation process. Thus, a central composite design (CCD) module in response surface methodology was employed to optimize the interactions of process variables, namely current density, contact time and initial pH targeted on maximum removal of chemical oxygen demand (COD), colour and turbidity with satisfactory pH of discharge POME. The batch study was initially designed by CCD and statistical models of responses were subsequently derived to indicate the significant terms of interactive process variables. All models were verified by analysis of variance showing model significances with Prob > F < 0.01. The optimum performance was obtained at the current density of 56 mA/cm(2), contact time of 65 min and initial pH of 4.5, rendering complete removal of colour and turbidity with COD removal of 75.4%. The pH of post-treated POME of 7.6 was achieved, which is suitable for direct discharge. These predicted outputs were subsequently confirmed by insignificant standard deviation readings between predicted and actual values. This optimum condition also permitted the simultaneous removal of NH3-N, and various metal ions, signifying the superiority of the electrocoagulation process optimized by CCD.


Assuntos
Técnicas Eletroquímicas , Óleos de Plantas/química , Eliminação de Resíduos Líquidos/métodos , Análise da Demanda Biológica de Oxigênio , Resíduos Industriais/análise , Malásia , Modelos Estatísticos , Modelos Teóricos , Óleo de Palmeira , Lagoas , Eliminação de Resíduos Líquidos/economia
12.
Environ Sci Pollut Res Int ; 31(1): 1468-1487, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38041733

RESUMO

Africa faces significant economic and environmental challenges, including waste generation, food insecurity, and energy inefficiency, jeopardizing future generations. To address this, Africa has adopted the 10-year Sustainable Consumption and Production Framework for Africa (10-YFP), evident through national and local projects focusing on sustainable food and agriculture, technology transfer in water irrigation, and related initiatives. The Belt and Road Initiative (BRI) presents an opportunity for promoting green cooperation and sustainable development in Africa, though its impact on ethical production and consumption remains unexplored. This study evaluates the BRI's role in achieving Africa's Twelve Sustainable Development Goals (SDGs) and catalyzing responsible consumption and production. Through interviews and focus group discussions (FGDs) involving 42 participants from 19 African countries, thematic patterns emerged using the thematic inductive method. Findings indicate that BRI initiatives effectively integrate advanced technologies to enhance sustainable agriculture and industrial production. Notably, BRI investments in countries like Morocco, Algeria, Ethiopia, Kenya, and Zambia are fostering renewable energy projects to provide electricity to underserved communities. A stronger alignment between national sustainable development plans and the green BRI is essential to maximize the benefits without compromising BRI principles of inclusivity, coordination, coherence, and capacity building. This research fosters dialogue among academics, educators, government officials, business leaders, and investors about the transformative potential of China's BRI in African nations. By shedding light on the positive strides made by BRI programs, this study underscores the need for strategic synergy between international cooperation efforts and localized sustainability agendas, ultimately propelling Africa toward its long-term development goals.


Assuntos
Energia Renovável , Desenvolvimento Sustentável , Humanos , Desenvolvimento Econômico , Etiópia , China , Dióxido de Carbono/análise
13.
Artigo em Inglês | MEDLINE | ID: mdl-23445415

RESUMO

The objective of this study was to investigate the performance of employing Fenton's reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and Fenton dosage, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD), color, NH-N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 90 min, 30 g/m³ ozone, 0.01 mol/L2H2O,0.02 mol/L Fe²âº, and pH 5. COD, color, and NH3-N removal rates of 79%, 100%, and 20%, respectively, and 0.18 kg O3/kg COD OC were obtained. The predictions correspond well with experimental results (COD, color, and NH-N removal rates of 78%, 98.5%, and 19%, respectively, and 0.29 kg O3/kg COD OC). This method reduces the treatment time and improves the treatment efficiency relative to a previously published method that used Fenton's reagent prior to ozonation.


Assuntos
Peróxido de Hidrogênio/química , Ferro/química , Ozônio/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Amônia/análise , Análise da Demanda Biológica de Oxigênio , Cor , Concentração de Íons de Hidrogênio , Modelos Químicos , Oxirredução , Ozônio/análise , Tempo de Reação , Espectrofotometria
14.
Chemosphere ; 339: 139699, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37532206

RESUMO

Sustainable energy transition has brought the attention towards microalgae utilization as potential feedstock due to its tremendous capabilities over its predecessors for generating more energy with reduced carbon footprint. However, the commercialization of microalgae feedstock remains debatable due to the various factors and considerations taken into scaling-up the conventional microalgal upstream processes. This review provides a state-of-the-art assessment over the recent developments of available and existing microalgal upstream cultivation systems catered for maximum biomass production. The key growth parameters and main cultivation modes necessary for optimized microalgal growth conditions along with the fundamental aspects were also reviewed and evaluated comprehensively. In addition, the advancements and strategies towards potential scale-up of the microalgal cultivation technologies were highlighted to provide insights for further development into the upstream processes aimed at sustainable circular bioeconomy.


Assuntos
Microalgas , Biocombustíveis , Biotecnologia , Bioengenharia , Biomassa
15.
Environ Sci Pollut Res Int ; 29(29): 44779-44793, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35138542

RESUMO

In this study, palm oil mill effluent (POME) treated by ultrasonication at optimum conditions (sonication power: 0.88 W/mL, sonication duration: 16.2 min and total solids: 6% w/v) obtained from a previous study was anaerobically digested at different hydraulic retention times (HRTs). The reactor biomass was subjected to metagenomic study to investigate the impact on the anaerobic community dynamics. Experiments were conducted in two 5 L continuously stirred fill-and-draw reactors R1 and R2 operated at 30 ± 2 °C. Reactor R1 serving as control reactor was fed with unsonicated POME with HRT of 15 and 20 days (R1-15 and R1-20), whereas reactor R2 was fed with sonicated POME with the same HRTs (R2-15 and R2-20). The most distinct archaea community shift was observed among Methanosaeta (R1-15: 26.6%, R2-15: 34.4%) and Methanobacterium (R1-15: 7.4%, R2-15: 3.2%). The genus Methanosaeta was identified from all reactors with the highest abundance from the reactors R2. Mean daily biogas production was 6.79 L from R2-15 and 4.5 L from R1-15, with relative methane gas abundance of 85% and 73%, respectively. Knowledge of anaerobic community dynamics allows process optimization for maximum biogas production.


Assuntos
Biocombustíveis , Reatores Biológicos , Anaerobiose , Metano , Óleo de Palmeira , Esgotos/microbiologia
16.
Environ Technol ; : 1-13, 2022 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-36428222

RESUMO

Oil palm fibre is a type of solid waste generated from palm oil processing plant. At present, there is no proper utilization of this abundant waste. Ammoniacal nitrogen (NH3-N) has received a lot of attention as a water pollutant due to its toxicity, which has an impact on both the environment and human health. In aquaculture wastewater (AQW), NH3-N is present in low concentrations (<10 ppm), and removing low concentrations of NH3-N is tedious. Thus, this study focuses on the potential of oil palm fibre biochar (OPFB) for sustainable low concentration NH3-N recovery from AQW and the recovered spent adsorbent to be used as a bio-fertilizer. The Physico-chemical properties of OPFB show a positive correlation with NH3-N recovery. A significant reduction of value-added metals in OPFB has confirmed the recovery of NH3-N through the ion exchange process. The adsorption isotherms and kinetics of NH3-N recovery had good correlation coefficients under the Freundlich and pseudo-second-order kinetic model confirming a multilayer heterogeneous and chemical adsorption respectively. Thermodynamic parameters indicated that the recovery process via adsorption was exothermic and had a Physio-chemical mechanism. At optimum conditions, OPFB could recover up to 66% of NH3-N actual AQW. The properties of spent OPFB showed potential reutilization as a soil amendment agent or biofertilizer which could be easily degraded.

17.
Sci Total Environ ; 815: 152949, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35007588

RESUMO

Contaminated groundwater is a priority issue on the environmental agendas of developed countries. Therefore, there is an obvious need to develop instruments and decision-making mechanisms that allow the estimation of the risk to human health due to the presence of contaminants in soils and groundwater, in a fast and reliable manner. Thus, this study aims to assess whether the spilling of hydraulic fracturing fluids prior to injection has a potential risk to groundwater quality in the Kern County Sub-basin, California, by identifying the hydrological factors and solute transport characteristics that control these risks while taking into consideration the temperature rises due to climate change. The approach uses the concept of the groundwater pollution risk based on comparing the concentration of pollutants within the water table by using a predetermined permissible level. The current average annual temperature and that by the end of the 21st century was used to estimate the diffusion of benzene through three types of soil by using HYDRUS-1D software. The software was used to predict the contaminant concentration profile of benzene in the water table with special reference to the impact of surface temperatures. The results showed that an expected rise of the surface temperature by 4.3 °C led to an increase in the concentration of benzene by 2.3 µg/l in sandy loam soil, 6.8 µg/l in silt loam soil, and finally, 2.6 µg/l in loam soil. The results show that climate change can substantially affect soil properties and their chemical constituents, which then play a major role in absorbing pollutants.


Assuntos
Água Subterrânea , Fraturamento Hidráulico , Poluentes Químicos da Água , Benzeno , Poluição Ambiental , Humanos , Solo , Poluentes Químicos da Água/análise
18.
Sci Total Environ ; 805: 150421, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-34818803

RESUMO

The emission of sulphur dioxide (SO2) gas from power plants and factories to the atmosphere has been an environmental challenge globally. Thus, there is a great interest to control the SO2 gas emission economically and effectively. This study aims to use and convert abundantly available oil palm fiber (OPF) biomass into an adsorbent to adsorb SO2 gas. The preparation of OPF biochar and activated biochar was optimised using the Response Surface Methodology (RSM) based on selected parameters (i.e., pyrolysis temperature, heating rate, holding time, activation temperature, activation time and CO2 flowrate). The best adsorbent was found to be the OPF activated biochar (OPFAB) compared to OPF biochar. OPFAB prepared at 753 °C for 73 min of activation time with 497 ml/min of CO2 flow yields the best adsorption capacity (33.09 mg/g) of SO2. Meanwhile, OPF pyrolysed at 450 °C of heating temperature, 12 °C/min of heating rate and 98 min of holding time yield adsorption capacity at 18.62 mg/g. Various characterisations were performed to investigate the properties and mechanism of the SO2 adsorption process. Thermal regeneration shows the possibilities for the spent adsorbent to be recycled. The findings imply OPFAB as a promising adsorbent for SO2 adsorption.


Assuntos
Carvão Vegetal , Dióxido de Enxofre , Adsorção , Pirólise
19.
Water Sci Technol ; 64(8): 1652-60, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22335108

RESUMO

Landfill leachate is one of the most recalcitrant wastes for biotreatment and can be considered a potential source of contamination to surface and groundwater ecosystems. In the present study, Fenton oxidation was employed for degradation of stabilized landfill leachate. Response surface methodology was applied to analyze, model and optimize the process parameters, i.e. pH and reaction time as well as the initial concentrations of hydrogen peroxide and ferrous ion. Analysis of variance showed that good coefficients of determination were obtained (R2 > 0.99), thus ensuring satisfactory agreement of the second-order regression model with the experimental data. The results indicated that, pH and its quadratic effects were the main factors influencing Fenton oxidation. Furthermore, antagonistic effects between pH and other variables were observed. The optimum H2O2 concentration, Fe(II) concentration, pH and reaction time were 0.033 mol/L, 0.011 mol/L, 3 and 145 min, respectively, with 58.3% COD, 79.0% color and 82.1% iron removals.


Assuntos
Peróxido de Hidrogênio , Ferro , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Aerobiose , Modelos Logísticos , Modelos Teóricos , Purificação da Água/métodos
20.
Sci Total Environ ; 776: 145961, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33640552

RESUMO

Waste management in Malaysia remains a persistent economic and environmental challenge. Up to date, more than 80% of Malaysian solid waste disposed at landfills and dumpsites. Therefore, Malaysia is facing an urgent need to move towards a sustainable solid waste management and thus resource recovery from organic solid waste. Hence, this study aims to investigate the feasibility of energy and bio fertilizer recovery from organic fraction municipal solid waste (OFMSW) via anaerobic digestion. The economic and environmental benefit analysis was investigated. Approximate and elementary analysis of OFMSW samples were carried out to estimate the potential production of biogas and bio fertilizer. It was found that organic waste contributes about 45% of the total MSW generated in Malaysia. Anaerobic digestion of 50% of organic waste is expected to produce 3941 MWh/day of electrical energy and 2500 t/day of bio fertilizer. In terms of environmental impacts, 2735 t/day of Carbon dioxide (CO2) emission, 1128 m2/day of landfilling area and 481 m3/day of leachate can be avoided. A net revenue of 3300 million RM (1 US Dollar ≈ 4.15 RM) can be generated by the sales of electricity via Feed-in-Tariff (FiT), sales of biofertilizer to local agricultural industries and inclusive of the saving generated from the reduction of OFMSW landfilling operations and leachate treatment at landfills. Economic development can go hand-in-hand with environmental sound practices in the field of waste management.


Assuntos
Eliminação de Resíduos , Resíduos Sólidos , Anaerobiose , Biocombustíveis/análise , Reatores Biológicos , Conservação dos Recursos Naturais , Malásia , Metano , Resíduos Sólidos/análise
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA