This article investigates the problem of simultaneous attitude and vibration control of a flexible spacecraft to perform high precision attitude maneuvers and reduce vibrations caused by the flexible panel excitations in the presence of external disturbances, system uncertainties, and actuator faults. Adaptive integral sliding mode control is used in conjunction with an attitude actuator fault iterative learning observer (based on sliding mode) to develop an active fault tolerant algorithm considering rigid-flexible body dynamic interactions. The discontinuous structure of fault-tolerant control led to discontinuous commands in the control signal, resulting in chattering. This issue was resolved by introducing an adaptive rule for the sliding surface. Furthermore, the utilization of the sign function in the iterative learning observer for estimating actuator faults has not only enhanced its robustness to external disturbances through a straightforward design, but has also led to a decrease in computing workload. The strain rate feedback control algorithm has been employed with the use of piezoelectric sensor/actuator patches to minimize residual vibrations caused by rigid-flexible body dynamic interactions and the effect of attitude actuator faults. Lyapunov's law ensures finite-time overall system stability even with fully coupled rigid-flexible nonlinear dynamics. Numerical simulations demonstrate the performance and advantages of the proposed system compared to other conventional approaches.

The main task of this work is related with the design of a class of SISO robust control law for the regulation of substrate concentration (CDO) of an Industrial Activated Sludge Wastewater Plant. The control design is related with an uncertainty estimator (reduced order observer) based Active Control. Departing from the tracking error between the desired and the current substrate concentrations trajectories a control law is designed and the plant is regulated to the corresponding set point of the COD concentration. To be realizable the controller needs model information related with the kinetic term of COD consumption which is provides with a reduced order observer, these coupled structure (observer based controller) is robust against model uncertainties. The performance of the proposed control law is illustrated with numerical simulations employing a mathematical model of an Industrial Activated Sludge Wastewater Plant tuned with industrial data.

In this experiment, active sewage sludge was inoculated in organic waste. The objective was to study its effect on nutrient dynamics during vermicomposting. Active sewage sludge, as a source of nitrogen fixing and phosphorous solubilizing bacteria, was added in four combinations to the vermicomposting substrate. Prior to inoculation with active sludge, the treatments were precomposted for 30 days and finally vermicomposted for 40 days. Results showed that inoculation of microorganisms in the substrate accompanied by earthworms’ activity enhances the organic waste biodegradation rate. Increasing sludge concentration from 0 to 6000 mg/l led to reduced Total Organic Carbon from 32.76 to 29.91%, Total Volatile Solids from 49.85 to 48/02%, and C/N ratio from 19.59 to 16.06 but increased Total Kjeldahl Nitrogen from 1.68 to 1.87%, nitrate from 1476.75 to 1699.60 mg/kg, Total Phosphorous from 1.66 to 1.77 g/kg, and Electrical Conductivity from 3.10 to 3.48 mS/cm. By increasing the concentration of sewage sludge, heavy metals content also increased significantly due to the enhanced organic matter biodegradation. Finally, the results showed that, among the treatments, the one with an active sewage sludge concentration of 6000 mg/l had more desirable effects on the final vermicompost quality.Based on the reproducibility of the process and the quality of the final products, this experimental procedure may be proposed for studies requiring a mass reduction in the initial composted waste mixtures.

Bioremediation of metal pollutants from industrial wastewater using metal resistant bacteria is a very important aspect of environmental biotechnology. In this study, three species of Pseudomonas aeruginosa were isolated from active sludge of a food factory in the city of Kerman. The bacterial identity was determined by various biochemical tests. Among them, isolate number one could grow on Muller-Hinton agar medium containing 6mM cadmium ion (Cd2+) and was therefore selected for further study. The isolates were subjected to mutation by two mutagenic agents (Acridine Orange and Acriflavine) using gradient plate and SIC techniques. The Minimum Inhibitory Concentration of Cd2+ for the isolate one after mutation was increased to 7mM. Removal of Cd2+using mutated and wild type strains of this bacterium was carried out at different time intervals (10-300 minutes). It was observed that within 60 minutes, 94.7% of cadmium was removed in 30mg/L of Cd2+ solution. However, with 60mg/L Cd2+ solution, only 53.58% and 38.68% Cd2+ removed were achieved by mutated and wild type bacteria, respectively. The equilibrium data was fitted by Langmuir isotherm equation and the related parameters for Cd2+ were derived. Based on the data obtained in this study, it can be concluded that biomass of this bacterium can be used for bioremediation of cadmium from industrial waste processing plants with high efficiency.

The objective of this study was to investigate the effect of various active carbon weights (100 and 150 g)and sizes (0.3, 1.5 and 4 mm) on the remediation of soil hydrocarbon pollution and monitor the negative impacts of petroleum hydrocarbons on parameters such as C/N, electrical conductivity (EC) and hydrophobicity of aggregates in petroleum polluted soil. This pilot study was conducted over 60 days as a split-plot in time experiment based on a completely randomized design with three replicates and included seven treatments (W100S0.3, W100S1.5, W100S4, W150S0.3, W150S1.5, W150S4, C), in which w and s indicated active carbon weight (g) and size (mm), respectively. The results showed that the application of active carbon at smaller sizes resulted in a significant decrease in the concentrations of C, N, C/N, pH, and total petroleum hydrocarbons )TPH(.. Active carbon treatment with 150 g weight and 0.3 mm size was the most effective treatment in TPH biodegradation, reduction of organic carbon content and C/N ratio in the polluted soil. Also, this treatment decreased aggregate hydrophobicity and dispersible clay percentage by TPH degradation.

The removal of four pharmaceutically active compounds, i.e., anti-inflammatory painkiller diclofenac (DCF), lipid-regulating agent clofibric acid (CFA), epilepsy drugs carbamazepine (CBM), and broad-spectrum anti-bacterial agent triclosan (TCS), present in sewage sludge was investigated using anaerobic digestion processes in the mesophilic and thermophilic modes. Sludge retention times (SRTs) were set at 10, 15, and 20 days, respectively, for the mesophilic mode and 7, 15, and 20 days, respectively, for the thermophilic mode. The effective isolation and purification pre-treatment to extract the target compounds from the sewage sludge samples were firstly established, followed by gas chromatography-mass spectrometer analysis to identify and quantify them. The removal efficiencies of the target compounds could be raised to a certain extent with the increase on SRTs, especially under the mesophilic condition. The removal of CFA and TCS under thermophilic condition hardly varied when the SRTs were above 15 days. All the compounds could be partly removed from the sewage sludge under the two temperature conditions, particularly TCS that was reduced by about 74%. Besides, CFA, firstly reported in this study, could be reduced by maximal 65%. On the whole, the thermophilic mode was more conducive to the removal of CBM and TCS, but did not have a noticeable effect on the removal of CFA. Furthermore, DCF could be better removed in the mesophilic mode. In addition, NH3-N accumulation in this measured range might positively affect the removal of the selected compounds, particularly in the mesophilic mode.

Background and Aim: Methyl-tributylether (MTBE) is a volatile organic compound which has detrimental effects on the environment, surface water and groundwater resources and it can change the taste of drinking water. The aim of this research was to determine the efficiency of activated sludge reactor with fixed bed in biological removal of methyl-tri-butyl ether from synthetic wastewater.Materials and Methods: This was an intervention-applicable study. The applied reactor was made of plexiglas and after transfer of activated sludge to it; the system ran for 4 weeks discontinuously. During a period of one month, concentration of glucose of the solution reduced and that of MTBE increased. 32 days after running the system, the whole COD input was provided through MTBE. COD, TSS, MLSS, SVI, temperature, PH, and dissolved oxygen parameters were analyzed in duplicate forms by excel software.Results: The results of this research indicated that by increasing the organic input load, the efficiency of the reactor decreased to some extent. The mean values of efficiency of COD removal during hydraulic remains of 4, 6, 8 and 10 hours were 82.7, 92.45, 95.97 and 96.1%, respectively.Conclusion: The results of this study showed with organic loadings up to 3 and 4/5 kg COD/m 3.d, the combined activated sludge reactor with fixed bed is capable of meeting the standards of household and industrial wastewater according to the standards of Environmental Protection Organization of Iran as to effluent wastewater COD for discharge in accepting water resources. Therefore we can conclude that the activated sludge reactor with fixed bed is an efficient, reliable and applicable technology for the treatment of strong wastewater.