A novel process for ethanol or biogas production from cellulose in blended-fibers waste textiles

A novel process has been developed for separation of the cellulose, i.e. cotton and viscose, from blended-fibers waste textiles. An environmentally friendly cellulose solvent, N-methylmorpholine-N-oxide (NMMO) was used in this process for separation and pretreatment of the cellulose. This solvent was mixed with blended-fibers textiles at 120 °C and atmospheric pressure to dissolve the cellulose and separate it from the undissolved non-cellulosic fibers. Water was then added to the solution in order to precipitate the cellulose, while both water and NMMO were reused after separation by evaporation. The cellulose was then either hydrolyzed by cellulase enzymes followed by fermentation to ethanol, or digested directly to produce biogas. The process was verified by testing 50/50 polyester/cotton and 40/60 polyester/viscose-blended textiles. The polyesters were purified as fibers after the NMMO treatments, and up to 95% of the cellulose fibers were regenerated and collected on a filter. A 2-day enzymatic hydrolysis and 1-day fermentation of the regenerated cotton and viscose resulted in 48 and 50 g ethanol/g regenerated cellulose, which were 85% and 89% of the theoretical yields, respectively. This process also resulted in a significant increase of the biogas production rate. While untreated cotton and viscose fibers were converted to methane by respectively, 0.02% and 1.91% of their theoretical yields in 3 days of digestion, the identical NMMO-treated fibers resulted into about 30% of yield at the same period of time.     

Controlling bacterial leaf blight of rice and enhancing the plant growth with endophytic and rhizobacterial Bacillus strains

This study was conducted to assess efficacy of biological control against bacterial leaf blight (BLB) of rice produced by Xanthomonas oryzae pv. oryzae. Five endophytic strains (A1, A2, A3, A13 and A15) and two rhizospherial Bacilli (D29 and H8) were tested for their antagonistic activities against BLB in vitro and in vivo. All seven strains showed high potential of antagonistic activity against X. oryzae pv. oryzae and three phytopathogenic fungi in vitro. Test of 16SrRNA gene sequence were assigned isolates A1, A3 and A13 as Bacillus amyloliquefaciens while isolates A2 and A15 as B. methylotrophicus and B. subtilis, respectively. In greenhouse, four strains of displayed 50.29%–57.86% inhibition rate against the pathogen and significantly increased plant fresh weight from 50.03% to 73.11% and dry weight from 64.11% to 86.65% in treated rice plants. In addition, these strains demonstrated strong capability to produce indole-3-acetic acid, siderophores, solubilizing phosphate and also colonize roots. Real-time quantitative polymerase chain reaction revealed that expression of defense-related genes including OsAOS2, OsJMT1, OsNPR1 and OsPR1b were significantly up-regulated in leaves of D29-exposed rice plants, suggesting that treatment of rice with D29 suppressed BLB through systemic activation of the plant defense system. Therefore, data suggest that Bacillus isolates A13, A15, D29 and H8 support effective antagonistic activity against BLB under greenhouse conditions in addition to their potential to promote growth of rice plants.     

Degradation of sericin (degumming) of Persian silk by ultrasound and enzymes as a cleaner and environmentally friendly process

Degumming is a surface modification process of natural fibers such as silk. In this paper, the feasibility of degumming with ultrasonic, ultrasonic–soap, and ultrasonic–enzyme (alcalase, savinase, and mixtures of these enzymes) processes as cleaner and environmentally friendly surface modification techniques of Persian silk were investigated. The effectiveness of parameters such as sonication time, soap, ultrasound–enzyme, enzyme concentration, degumming time and enzymes mixture on silk degumming were studied. The evaluation of the data was carried out through the measurement of the weight loss, strength, and elongation of the samples. In addition, the enzymatic treatment improved the properties of silk yarn such as strength and elongation. The scanning electron microscope images were obtained for degummed silk samples. The findings of this research support the potential production of new environmentally friendly textile fibers.     

50 Hz alternating extremely low frequency magnetic fields affect excitability,firing and action potential shape through interaction with ionic channels in snail neurones

In spite of growing concern about the influence of magnetic fields on biological systems, the interaction between extremely low frequency magnetic field (ELF magnetic fields) and biological structures at the cellular level remains obscure. The aim of this study was to investigate if 50 Hz magnetic fields could have an effect on the neuronal excitability and firing responses. Under Current-Clamp condition, exposure to 50 Hz ELF magnetic fields at 2 mT or 0.8 mT intensities resulted in an increase in the peak amplitude of action potential and after hyperpolaization potential in a time dependent manner. Both magnetic field intensities decreased also the firing frequency and the duration of action potential. Taken together, these data suggest that 50 Hz ELF magnetic fields at 2 mT or 0.8 mT intensities may change the electrophysiological behavior of neuronal cells and underlying ion channel currents.     

Optimizing stabilization of waste-activated sludge using Fered-Fenton process and artificial neural network modeling (KSOFM,MLP)

Sludge management is a fundamental activity in accordance with wastewater treatment aims. Sludge stabilization is always considered as a significant step of wastewater sludge handling. There has been a progressive development observed in the approach to the novel solutions in this regard. In this research, based on own initially experimental results in lab-scale regarding Fered-Fenton processes in view of organic loading (volatile-suspended solids, VSS) removal efficiency, a combination of both methods towards proper improving of excess biological sludge stabilization was investigated. Firstly, VSS removal efficiency has been experimentally studied in lab-scale under different operational conditions taking into consideration pH [Fe²⁺]/[H₂O₂], detention time [H₂O₂], and current density parameters. Therefore, the correlations of the same parameters have been determined by utilizing Kohonen self-organizing feature maps (KSOFM). In addition, multi-layer perceptron (MLP) has been employed afterwards for a comprehensive evaluation of investigating parameters correlation and prediction aims. The findings indicated that the best proportion of iron to hydrogen peroxide and the optimum pH were 0.58 and 3.1, respectively. Furthermore, maximum retention time about 6 h with a hydrogen peroxide concentration of 1,568 mg/l and a current density of 650–750 mA results to the optimum VSS removal (efficiency equals to 81 %). The performance of KSOFM and MLP models is found to be magnificent, with correlation ranging (R) from 0.873 to 0.998 for the process simulation and prediction. Finally, it can be concluded that the Fered-Fenton reactor is a suitable efficient process to reduce considerably sludge organic load and mathematical modeling tools as artificial neural networks are impressive methods of process simulation and prediction accordingly.     

Biofiltration of gas-phase hexane and toluene mixture under intermittent loading conditions

This paper reports the performance of a compost biofilter subjected to periodic intermittent loads of gas-phase hexane and toluene. The biofilter was operated for 10 h per day, at different empty bed residence times (4, 2 and 1.3 min), and at different inlet concentrations of hexane and toluene, varying between 2 and 3.8 g m^?3, respectively. Steady-state removal efficiency profiles, reaching more than 90% for both the pollutants, was observed after 44 days of operation. Periodic operation of the compost biofilter was characterized by an adsorption step, followed by biological conversion of the pollutants by the microorganisms inherent to the compost. After resuming daily biofilter operation, the required times for biochemical reaction to dominate the initial adsorption step was observed to be 2.5 and 1 h, respectively, for toluene and hexane. The maximum elimination capacity due to the biological step was found to be 61.6 g m^?3 h^?1. The results from this study showed the effectiveness of the biofilter to handle mixtures of gas-phase pollutants, subjected to regular intermittent operations, thus proving their worthiness for industrial use.     

A STOCHASTIC DYNAMIC PROGRAMMING MODEL FOR THE OPTIMUM OPERATION OF A MULTI-PURPOSE RESERVOIR1

ABSTRACT: The main objective of this paper is to present a stockastic dynamic programming model useful in determining the optimal operating policy of a single multipurpose surface reservoir. It is the unreliability of forecasting the amount of future streamflow which makes the problem of a reservoir operation a stochastic process. In this paper the stochastic nature of the streamflow is taken into account by considering the correlation between the streamflows of each pair of consecutive time intervals. This interdependence is used to calculate the probability of transition from a given state and stage to its succeeding ones. A dynamic programming model with a physical equation and a stochastic recursive equation is developed to find the optimum operational policy. For illustrative purposes, the model is applied to a real surface water reservoir system.     

RESISTANCE TO FLOW OVER RIPRAP IN STEEP CHANNELS1

ABSTRACT: A series of flume tests were conducted to determine the flow resistance of angular shaped riprap in steep channels. Flow resistance was expressed in terms of the Darcy-Weisbach friction factor and the Manning's roughness coefficient. Prototype channels of 4 ft. (1.2 m) and 12 ft. (3.7 m) in width were constructed at slopes ranging from 0.01 to 0.20. The channel beds were comprised of angular riprap of median diameters of 1, 2, 4, 5, and 6 inches (2.59, 5.59, 10.41, 12.95, and 15.75 cms). The Darcy-Weisbach and Manning's coefficients were determined for each test condition prior to bed failure. The resulting Darcy-Weisbach coefficients were related to the channel energy gradient and the bed relative submergence for highly turbulent flow. Also, Manning's roughness coefficients were related to the product of the median stone diameter and energy gradient. Because of the angular shape of the riprap and the wedging and/or packing of the bed materials, the resistance to flow was found to exceed the flow resistance values predicted by previous studies. Expressions were presented for estimating the resistance to flow for angular riprap in steep channels.     

Quality of drinking water in the Aligarh Muslim University Campus,Aligarh, U.P. (India) with respect to heavy metals

The physico-chemical characteristics of the drinking water in nine residential halls of the Aligarh Muslim University, Aligarh, U.P. (India), were studied. Nine samples each of running and standing water were taken four times over a period of one month at weekly intervals from all of the residential halls and were analysed for physico-chemical characteristics and heavy metal contents. The temperature, pH and electrical conductivity of water samples ranged between 20.0–26.0°C; 7.00–8.00 and 116.00–199.04 micromhos cm^–1 respectively whereas the values of total alkalinity, total hardness, Cl^–, SO ₄ ^– , F^–, NH₃–N, NO₂–N; NO₃–N were found between 261.00–396.00; 128.00–200.00; 8.00–69.00; 12.00–46.00; 0.90–1.35; 0.20–0.44; ND; 1.60–6.50 mg l^–1 respectively. The ranges of heavy metal concentrations in the running water samples were as follows: Cd (0.70–3.75); Cr (ND-5.00); Co (9.50–18.75); Cu (0.75–15.00); Fe (ND-13.50); Mn (3.50–51.00); Ni (7.00–17.50); Pb (0.50–2.50) and Zn (10.00–176.50) g l^–1. The heavy metal concentrations in standing water samples were found to be: Cd (1.20–4.90); Cr (ND-10.00); Co (10.25–19.00); Cu (1.75–20.00); Fe (ND-18.00); Mn (5.00–66.50); Ni (8.75–19.75); Pb (0.75–5.50) and Zn (28.60–364.00) g l^–1. The concentrations of heavy metals in drinking water supplies of the Aligarh Muslim University campus were well below the guidelines for drinking water quality as prescribed by World Health Organisation (1984). It is evident from the results that the drinking water may not cause any significant health hazard to water consumers due to heavy metals but these may be hazardous if they get accumulated in the body due to continuous consumption of water.