• Energy Research

Hydraulic fracturing drilling technology can cause a high risk of surface spill accidents and thus water contamination. Climate change together with the high water demand and rapid increase in industrial and agricultural activities are valued reasons why we should all care about the availability of water resources and protect them from contamination. Hence, the purpose of this study is to estimate the risk associated with a site contaminated with benzene from oil spillage and its potential impact on groundwater. This study focused on investigating the impact of soil variability and water table depth on groundwater contamination. Temperature-dependent parameters, such as soil water content and the diffusion of pollutants, were considered as key input factors for the HYDRUS 1D numerical model to simulate benzene migration through three types of soil (loamy, sandy clay loam, and silt loam) and evaluate its concentration in the water aquifer. The results indicated that an anticipated increase in earth’s average surface temperature by 4 °C due to climate change could lead to a rise in the level of groundwater pollution in the study area by 0.017 mg/L in loamy soil, 0.00046 mg/L in sandy clay loam soil, and 0.00023 mg/L in silt loam soil. It was found that climate change can reduce the amount of benzene absorbed from 10 to 0.07% in loamy soil, 14 to 0.07% in sandy clay loam soil, and 60 to 53% in silt loam soil. The results showed that the soil properties and solute characteristics that depend on the temperature have a major and important role in determining the level of groundwater pollutants.

The prime objective of this study was to simultaneously enhance the lipid and protein yields from black soldier fly larvae (BSFL) fed with mixture of waste coconut endosperm and soybean curd residue. The waste coconut endosperm that loss nutrient content during milk extraction was fortified to increase the nutritive value via self-fermentation process within 4 weeks before mixing it with soybean curd residue. The following six feed mixtures of waste coconut endosperm: soybean curd residue (C:S) were formulated: 5:0, 4:l, 3:2, 2:3, l:4 and 0:5. The results showed peak lipid content was attained from 3:2 feed mixtures. Using this feed mixture mediums, the BSFL prepupae could accumulate 58% and 2l% of its biomass weight with lipid and protein respectively. Tn considering of organic waste treatment, 3:2 feed mixture showed an efficiency of conversion of digested food (ECD) of 0.20l. Therefore, mix ratio of 3:2 was concluded as an optimum to produce ideal mixture feed medium for BSFL in enhancing the simultaneous lipid and protein yields.

Abstract A synthetic natural gas (syngas) production study via municipal solid waste (MSW) gasification system in a circulating fluidized bed gasifier is presented with the aim to produce clean energy. The syngas production offers a substantial energy alternative especially in regions such as Pakistan where the rates of MSW production are high and resources are less. MSW gasification could be an effective process that will not only contribute to solve solid waste problem but also reduces waste disposal landfills. The capacity of the plant was set based on the availability of feed and selexol process which was integrated with a carbon capture process. The energy conversion performance for the overall integrated process was evaluated based on material and energy balances and the system performance. The plant produced 30 MW of energy from a 50 MW estimated plant capacity. About 84% of syngas is produced from the overall process after capturing the carbon dioxide (CO2) using Selexol process. A process model was developed using ASPEN PLUS simulator to calculate the performance of the circulating fluidized bed (CFB) gasifier. Effect of gasification temperature, equivalence ratio, and moisture content was analyzed. Higher moisture content results in degradation of syngas quality. Large amount of MSW needs greater heat input and this increases the process cost. Gasifier temperatures were found to have a stronger impact on the syngas composition. The simulation results and energy balances in combination impart useful information in a search of proficient and clean utilization of MSW energy.

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.

The prime objective of this study was to simultaneously enhance the lipid and protein yields from black soldier fly larvae (BSFL) fed with waste coconut endosperm. The waste coconut endosperm impoverished with nutrient content lost during milk extraction was nutritively fortified via self-fermentation process with time period ranging from 2 to 8 weeks before administering to BSFL. The results showed peak nutrient content was attained from week-4 self-fermented waste coconut endosperm. Using this feed medium, the BSFL prepupae could accumulate 58% of its biomass weight with lipid. The low polyunsaturated fatty acid (6%) and high C18:1 (50%) also guaranteed high biodiesel quality derived from BSFL. Nevertheless, the longer BSFL rearing duration when fed with week-6 self-fermented waste coconut endosperm had triggered a slight increase in protein yield (18%) in comparison with week-4 medium (15%). In considering of organic waste treatment advantage of week-4 self-fermented waste coconut endosperm, a total waste reduction of 0.019 g/d was successfully measured using only 20 BSFL. Therefore, week-4 self-fermented period was concluded as an optimum to produce ideal waste coconut endosperm feed medium for BSFL in enhancing the simultaneous lipid and protein yields.

Cette étude vise à étudier les effets des cendres de boues d'alun partiellement carbonisées (ASA) qui avaient été traitées à la température de 200–300 °C et du laitier de haut fourneau granulé broyé (GGBFS) en tant que matériaux cimentaires supplémentaires sur les propriétés fraîches et durcies du mortier de ciment. Dans cette étude, 10 mélanges avec des niveaux de remplacement maximums de ciment Portland ordinaire (OPC) avec de l'ASA et du GGBFS jusqu'à 6,0 % en poids respectivement. Les essais de temps de prise et de table d'écoulement ont été effectués sur du béton frais, tandis que les propriétés durcies (densité, résistance à la compression, résistance à la flexion, coefficient d'absorption d'eau, porosité et absorption d'eau) ont été étudiées sur deux âges de durcissement du béton (c'est-à-dire après 7 jours et 28 jours). Les résultats ont montré que la résistance mécanique, la maniabilité et la densité du mortier avaient tendance à diminuer à mesure que le niveau de remplacement de l'OPC par l'ASA augmentait, tandis que le temps de prise augmentait avec l'augmentation de la teneur en ASA. En outre, l'ASA et le GGBFS ont amélioré le coefficient d'absorption d'eau et les propriétés d'absorption d'eau du béton à tous les âges. La résistance à la compression la plus élevée qu'un mortier puisse être produit à partir de cette étude après avoir été durci pendant 28 jours est de 20,6 MPa 2,0 % en poids d'ASA et 4,0 % en poids de GGBFS ont été utilisés pour remplacer partiellement l'OPC pour produire le mortier qui avait une ouvrabilité de 156 mm. Dans l'ensemble, l'incorporation d'ASA en remplacement partiel du ciment dans la production de mortier peut réduire en partie le volume de boues d'alun dans les décharges. Este estudio tiene como objetivo investigar los efectos de la ceniza de lodo de alumbre parcialmente carbonizada (ASA) que se había tratado a una temperatura de 200–300 °C y la escoria granulada de alto horno molida (GGBFS) como materiales cementosos complementarios sobre las propiedades frescas y endurecidas del mortero de cemento. En este estudio, 10 mezclas con niveles máximos de reemplazo de cemento Portland ordinario (OPC) con asa y GGBFS hasta 6.0% enpeso respectivamente. Las pruebas de tiempo de fraguado y tabla de flujo se realizaron en concreto fresco, mientras que las propiedades endurecidas (densidad, resistencia a la compresión, resistencia a la flexión, coeficiente de absorción de agua, porosidad y absorción de agua) se investigaron en dos edades de curado del concreto (es decir, después de 7 días y 28 días). Los resultados mostraron que las resistencias mecánicas, la trabajabilidad y la densidad del mortero tendían a disminuir a medida que aumentaba el nivel de reemplazo de OPC con el asa, mientras que el tiempo de fraguado aumentaba con el aumento del contenido de asa. Además, el asa y el GGBFS mejoraron el coeficiente de absorción de agua y las propiedades de absorción de agua del concreto en todas las edades. La resistencia a la compresión más alta que se puede producir un mortero a partir de este estudio después de ser curado durante 28 días es 20.6 MPa 2.0% en peso de asa y 4.0% en peso de GGBFS se utilizaron para reemplazar parcialmente OPC para producir el mortero que tenía una trabajabilidad de 156 mm. En general, la incorporación de asa como reemplazo parcial del cemento en la producción de mortero puede reducir en parte el volumen de lodos de alumbre en los vertederos. This study aims to investigate the effects of partially carbonized alum sludge ash (ASA) which had been treated at the temperature of 200–300 °C and Ground Granulated Blast Furnace Slag (GGBFS) as supplementary cementitious materials on fresh and hardened properties of cement mortar. In this study, 10 mixtures with maximum replacement levels of ordinary Portland cement (OPC) with ASA and GGBFS up to 6.0 wt% respectively. The setting time and flow table tests were performed on fresh concrete, while the hardened properties (density, compressive strength, flexural strength, water absorption coefficient, porosity and water absorption) were investigated on two concrete curing ages (i.e., after 7 days and 28 days). The results showed that, the mechanical strengths, workability, and density of mortar tended to decrease as the replacement level of OPC with the ASA increase, while the setting time increase with the increase of ASA content. In addition, the ASA and GGBFS enhanced the water absorption coefficient and water absorption properties of concrete at all ages. The highest compressive strength a mortar can be produced from this study after being cured for 28 days is 20.6 MPa 2.0 wt% of ASA and 4.0 wt% of GGBFS were used to partially replace OPC to produce the mortar which had workability of 156 mm. Overall, incorporation of ASA as a partial replacement of cement in mortar production can partly reduce the volume of alum sludge in landfill. تهدف هذه الدراسة إلى التحقيق في آثار رماد حمأة الألمنيوم المكربن جزئيًا (ASA) الذي تمت معالجته عند درجة حرارة 200–300 درجة مئوية وخبث فرن الصهر الحبيبي المطحون (GGBFS) كمواد أسمنتية تكميلية على الخصائص الطازجة والمصلدة لملاط الأسمنت. في هذه الدراسة، 10 مخاليط مع الحد الأقصى لمستويات استبدال الأسمنت البورتلاندي العادي (OPC) مع ASA و GGBFS تصل إلى 6.0 ٪ بالوزن على التوالي. تم إجراء اختبارات وقت الإعداد وجدول التدفق على الخرسانة الطازجة، بينما تم فحص الخصائص المتصلبة (الكثافة، مقاومة الانضغاط، مقاومة الانثناء، معامل امتصاص الماء، المسامية وامتصاص الماء) على عمرين لمعالجة الخرسانة (أي بعد 7 أيام و 28 يومًا). أظهرت النتائج أن القوة الميكانيكية للملاط وقابليته للتشغيل وكثافته تميل إلى الانخفاض مع زيادة مستوى استبدال OPC مع ASA، بينما يزداد وقت الإعداد مع زيادة محتوى ASA. بالإضافة إلى ذلك، عززت ASA و GGBFS معامل امتصاص الماء وخصائص امتصاص الماء للخرسانة في جميع الأعمار. أعلى قوة انضغاط يمكن إنتاج الملاط من هذه الدراسة بعد معالجته لمدة 28 يومًا هي 20.6 ميجا باسكال 2.0 ٪ بالوزن من ASA و 4.0 ٪ بالوزن من GGBFS تم استخدامها لاستبدال OPC جزئيًا لإنتاج الملاط الذي كان قابلاً للتشغيل 156 مم. بشكل عام، يمكن أن يؤدي دمج ASA كبديل جزئي للأسمنت في إنتاج الملاط إلى تقليل حجم حمأة الشب في مكب النفايات جزئيًا.