Development of granular sludge for textile wastewater treatment

Microbial granular sludge that is capable to treat textile wastewater in a single reactor under intermittent anaerobic and aerobic conditions was developed in this study. The granules were cultivated using mixed sewage and textile mill sludge in combination with anaerobic granules collected from an anaerobic sludge blanket reactor as seed. The granules were developed in a single sequential batch reactor (SBR) system under alternating anaerobic and aerobic condition fed with synthetic textile wastewater. The characteristics of the microbial granular sludge were monitored throughout the study period. During this period, the average size of the granules increased from 0.02 ± 0.01 mm to 2.3 ± 1.0 mm and the average settling velocity increased from 9.9 ± 0.7 m h⁻¹ to 80 ± 8 m h⁻¹. This resulted in an increased biomass concentration (from 2.9 ± 0.8 g L⁻¹ to 7.3 ± 0.9 g L⁻¹) and mean cell residence time (from 1.4 days to 8.3 days). The strength of the granules, expressed as the integrity coefficient also improved. The sequential batch reactor system demonstrated good removal of COD and ammonia of 94% and 95%, respectively, at the end of the study. However, only 62% of color removal was observed. The findings of this study show that granular sludge could be developed in a single reactor with an intermittent anaerobic-aerobic reaction phase and is capable in treating the textile wastewater.     

Formation of a Rhenium-base Diffusion-barrier-coating System on Ni-base Single Crystal Superalloy and its Stability at 1,423 K

A diffusion-barrier-coating system having a duplex structure comprised of an inner Re(W)–Cr–Ni layer and an outer Ni-aluminide layer was formed on a fourth generation, single-crystal Ni-base superalloy by using electroplating of Re(Ni) and Ni(W) films, Al- and Cr- (high-Cr and low-Cr) pack cementations, and a combination of the two treatments. With the ReW-high-Cr coating, fine needle- or plate-like precipitates formed in the alloy substrate below the inner Re(W, Cr, Ni) layer, while there was little of this precipitate with the ReW-low-Cr pack-cementation coating. The inner, Re-base alloy layer in the ReW-high-Cr coating was identified to be a σ-(Re,Cr,W,Ni) phase, while the inner layer of the ReW-low-Cr was a mixture of σ-(Re,Cr,W,Ni) and δ-Re(Cr,W,Ni) phases. After heating the coated alloys at 1,150 °C for 100 h in air, the outer Al reservoir layer became β-NiAl containing (31–33)Al with α-Cr particles and fine precipitates of γ′-Ni₃Al with both the ReW-high-Cr and ReW-low-Cr treatments. In the case of the ReW-high-Cr coating there were numerous light-colored, needle-like precipitates formed deep in the alloy substrate under the inner layer, while in the case of the ReW-low-Cr coating γ′ appeared near the inner layer. It was found that the inner, Re-base alloy layer acted as a diffusion barrier, and that its structure was maintained with little change in composition after 100 h of oxidation at 1,150 °C. K. Z. Thosin is from Indonesian Institute of Sciences, LIPI.     

Impact of full-scale brewing processes on lager beer nitrogen compounds

This paper analyses in a full-scale industrial process firstly the nitrogen compounds in all-malt and in maize-adjunct worts, then their fate during the main brewing steps and finally the influence on them of two different separation technologies: mash filter (Meura 2001) and lauter tun (Steinecker FVAS 26). Data showed that (1) maize-adjunct worts have a lower total nitrogen compounds than all-malt worts; (2) assimilable nitrogen represents 20–24% out of the total nitrogen in both all-malt and in adjunct worts; (3) free amino nitrogen nearly doubles in all-malt compared with adjunct worts; (4) proline and asparagine are the most abundant amino acids in both worts; (5) ammonium disappears during fermentation in wort with the lowest nitrogen content, i.e. in maize-adjunct wort. Moreover, the total nitrogen is reduced in all-malt by 80% with the Steinecker FVAS 26 lauter tun and 25% with the Meura 2001 filter, while in adjunct worts by 87% with the Steinecker FVAS 26 lauter tun and 29% with the Meura 2001 filter. After mash filtration, the content of assimilable nitrogen remains to be adequate for an efficient fermentation, but after lauter tun separation, the assimilable nitrogen reaches values that may compromise the regular fermentation process in both all-malt and adjunct worts. Therefore, when using lauter tun, we have to intervene to reduce its impact on nitrogen compounds and/or plan the wort nitrogen supplementation to overcome the stuck and sluggish fermentations.     

Geothermal energy extraction using abandoned oil and gas wells: Techno-economic and policy review

Retrofitting depleted oil wells to extract geothermal energy is considered as one of the promising proposals to extend the overall economic life of oil and gas well. For successful implementation of this initiative, a comprehensive overview covering all aspects of geothermal energy extraction from abandoned oil well should be taken into account including technical, economic considerations as well as regulations and policies of respective local governments. Unfortunately, most reported studies have been focused only on one or two aspects, primarily on technical and economic aspects. Little or no study has focused on the policy sector. Moreover, these findings have been scattered, creating difficulties to extract essential information and dragging further development of the technology. This paper is therefore prepared with the objective to provide a comprehensive overview on the geothermal energy extraction from abandoned oil well, technical challenges in its implementation, economical consideration on the conversion of the well and government policy on energy especially geothermal energy and regulation on the utilization of abandoned oil well. To achieve this objective, extensive literature reviews are conducted with more attention given to recent studies on the field. Challenges on the development of this technology are discussed from technical, economic, and policy perspectives. Based on the identified challenges, required research and development as well as necessary policies for further advancement of this technology are outlined and discussed. By providing this comprehensive information, this review paper may serve as a good foundation and guidelines on the conversion of abandoned oil wells into geothermal energy wells.     

Elastic and Plastic Strains Misfits During the Reverse Martensitic Transformation

Metallurgical and Materials Transactions A - The properties of technological interest of ferromagnetic shape memory alloys (FSMAs) are linked to the occurrence of a thermoelastic martensitic...     

Forecasting of Appliances House in a Low-Energy Depend on Grey Wolf Optimizer

This paper gives and analyses data-driven prediction models for the energy usage of appliances. Data utilized include readings of temperature and humidity sensors from a wireless network. The building envelope is meant to minimize energy demand or the energy required to power the house independent of the appliance and mechanical system efficiency. Approximating a mapping function between the input variables and the continuous output variable is the work of regression. The paper discusses the forecasting framework FOPF (Feature Optimization Prediction Framework), which includes feature selection optimization: by removing non-predictive parameters to choose the best-selected feature hybrid optimization technique has been approached. k-nearest neighbors (KNN) Ensemble Prediction Models for the data of the energy use of appliances have been tested against some bases machine learning algorithms. The comparison study showed the powerful, best accuracy and lowest error of KNN with RMSE = 0.0078. Finally, the suggested ensemble model's performance is assessed using a one-way analysis of variance (ANOVA) test and the Wilcoxon Signed Rank Test. (Two-tailed P-value: 0.0001).     

Tensile,thermal, flammability and morphological properties of sepiolite filled ethylene propylene diene monomer (EDPM) rubber composites

The effect of sepiolite loading content on the curing characteristics, tensile mechanical, thermal, swelling, flammability and morphological properties of sepiolite-filled ethylene propylene diene monomer (EPDM) composites was investigated. The composites were prepared with sepiolite loadings of 0–70 part per hundred (phr) of rubber using a two-roll mill. The results highlighted the improvement in the tensile properties and cross-link density values peaked at 60 phr of sepiolite loading. The scorch time, curing time, swelling percentage, and linear burning rate of the composites decreased with an increase in sepiolite loading. Thermogravimetric analysis showed an increasing trend with increase in sepiolite loading. The temperatures corresponding to 5, 25 and 50% weight loss (T_5wt%, T_25wt% and T_50wt%) and the percentage of char residue gradually increased with increase in sepiolite loading. The homogenous dispersion of the sepiolite particles in the EPDM matrix and the formation of zigzag structures, especially at 60 phr, were the main reasons of the improvement of mechanical properties which were confirmed by the morphological studies. The formation of a protective layer, which acted as a barrier against heat transfer into the deeper layers, enhanced the flammability resistance of the composites. Notably, the EPDM filled with 60 phr sepiolite exhibited excellent performance in the aspects of mechanical, thermal stability and flammability properties and resistance towards swelling.     

Electricity generation using membrane-less microbial fuel cell powered by sludge supplemented with lignocellulosic waste

A membrane-less microbial fuel cell (ML-MFC) is an electrochemical device that incorporates microorganisms into the design in order to produce electricity through biologically catalyzed oxidation of soluble, electron-donating substrates. In this study, three lignocellulosic raw materials were added into the ML-MFC whereby the sludge acted as the pseudomembrane. All three materials were used as the substrates in ML-MFC for the production of electricity that was measured using a digital multimeter. Results showed that the ML-MFC that contained sludge supplemented with banana peel produced the highest electricity, followed by corn bran and palm oil mill effluent (POME) at 237.1 mV (23.75 mW/m²), 176.8 mV (12.65 mW/m²), and 138 mV (22.03 mW/m²) after 138 h, 192 h, and 108 h of incubation period, respectively. For the control test (sludge only), about 162.7 mV was recorded at shorter incubation period (84 h). This showed that long-term operation of the ML-MFC using these complex lignocellulosic compounds as a direct substrate for electricity generation is feasible, though their degradation is slow.