Three vertical sub-surface flow (VSSF) constructed wetland (CW) systems (CW-1, CW-2 and CW-3) filled with different filter media, each 4 m2 in area, planted with Arundo donax was operated for 4 years for treating dairy farm wastewater. The vertical CW systems received high fluctuations in influent concentration and loads i. e. BOD (26 to 619 mg L-1 and 1. 5 to 34 g m-2 d-1), TSS (165 to 643 mg L-1 and 9. 1 to 24 g m-2 d-1), TP (16 to 49. 9 mg L-1 and 1. 2 to 2. 7 g m-2 d-1) and NH4-N (24. 5 to 76. 2 mg L-1 and 1. 3 to 4. 2 g m-2 d-1) during the assessment period. Average annual removal rates showed fluctuations in removal of BOD (70. 5 to 92. 9%), TSS (82. 5 to 97. 5%), TP (51. 1 to 91. 9%) and NH4-N (34. 6 to 69%). This shows that the removal of BOD is very sensitive to inlet load fluctuations in CWs. High inlet loads may confine good nitrification that affects ammonium-nitrogen removal while TP removal rate reduced when inlet TP loads reduced. The average concentration of the pollutants (BOD, TSS, TP and NH4-N) in the treated effluent showed noticeable decrease: 43. 4 to 16. 1 mg L-1 for BOD, 43. 3 to 11. 7 mg L-1 for TSS, 17. 9 to 3. 1 mg L-1 for TP and 33. 2 to 22. 7 mg L-1 for NH4-N. Thus from the outcomes of the current study, it can be concluded that the VSSF CW system may provide promising outcomes despite there is fluctuations in the influent loads.

Plastic hinge properties play a crucial role in predicting the nonlinear response of structural elements. The plastic hinge region of reinforced concrete normal beams has been previously studied experimentally and analytically. The main objective of this research is to evaluate the behavior of the plastic hinge region of reinforced concrete deep beams and its comparison with normal beams through finite element simulation. To do so, ten beams contain six deep beams, and four normal beams, under concentrated and uniformly distributed loading, are investigated. Lengths in the plastic hinge region involving curvature localization, rebar yielding, and concrete crushing zones are studied. The results indicate that the curvature localization zone is not suitable for the prediction of plastic hinge length in reinforced concrete deep beams. Based on the results it can be stated that in simply supported normal beams the concrete crushing zone is focused on the middle span, but in simply supported deep beams by creating a compression strut between loading place and support, the concrete crushing zone spreads along the compression trajectory. The rebar yielding zone of simply supported beams increases as the loading type is changed from the concentrated load at the middle to the uniformly distributed load.

This study aims to determine and prioritize effective KM success factors. The first step is to implement KM in STPs. As regards the major goal of science and technology parks is assisting the growth of society wealth through developing knowledge based innovations and intensifying competition among knowledge-based institutions. Assessing knowledge management in science and technology parks will be considered as a substantial tool for creation, development, sharing and linking knowledge to technology. So based on literature studies and experts ideas 31 sub-factors were organized in 7 categories as follows: labor, strategy, supervisor, assessment, culture, operation and information technology. In fact these categories are effective KM success factors which have been weighed and prioritized by utilizing analytic hierarchy process (AHP).The order of effective KM success factors in terms of importance are labor, strategy, supervision, culture, operation, assessment and information technology. Two sub factors with highest influence on KM have been selected among numerous numbers of factors. Finally this model is applied for evaluating nine incubators in Yazd science and technology park.

Background and Objective: Considering the importance of alkalinity in pH regulation and its buffering role, in this study, the effect of inlet wastewater alkalinity on the efficiency of the anaerobic unit of the wastewater treatment plant. Moreover, a superior chemical compound in providing alkalinity to wastewater was investigated. Materials and Methods: This study was performed in the treatment plant to determine the relationship between input alkalinity and removal efficiencies of COD, BOD5 and TSS. In order to determine the optimal alkali material for superb anaerobic wastewater performance, four common chemical substances including, NaOH, Na2CO3, Ca(OH)2 and MgO were selected and examined using One Factor At Time (OFAT) test method. Results: According to the results maximum removal efficiencies were obtained 62, 66. 6 and 71. 2% for COD, BOD5 and TSS, respectively under alkaline condition of 1260 mg/L CaCO3. Furthemore, the optimal dose to supply one unit of alkalinity by Na2CO3, Ca(OH)2 and MgO were 0. 53, 0. 54 and 0. 3 mg/L, respectively. These values were obtained 5 min contact time and mixing rate of 150 rpm. However, for NaOH the optimal dose supply was obtained 0. 35 mg/L for 3 min contact time and mixing rate of 100 rpm. Conclusion: In conclusion, the performance of anaerobic baffled reactor is highly related to the supply of influent alkalinity to the reactor. In addition, the use of MgO can be considered as a suitable alkaline substance to neutralize acidic wastewater and provide alkalinity for ABR system.

Nitrification, the oxidation of ammonia to nitrate catalyzed by bacteria, is a key part of the global nitrogen cycle. In the first step of nitrification, chemolithoautotrophic ammonia oxidizers transform ammonia to nitrite, which subsequently oxidizes to nitrate by nitrite-oxidizing bacteria. This process can be affected by several factors. In this study, the effect of influent COD/N ratio on nitrification rate in a bench-scale biological reactor was investigated. Experiments were carried out using synthetic wastewater. The initial ammonium concentration was 25 mg NH+4 -N L-1. The effect of COD/N ratio between 10.01±0.083 and 24.08±0.22 gCODgN-1 on nitrification rate was investigated by varying the COD loading supplied to the reactor. From the results obtained, it may be concluded that in the range of 10.01±0.083 to 14.15±0.17 gCODgN-1, a direct relationship holds between COD/N ratio and nitrification rate. However, an indirect relationship holds between COD/N ratio and nitrification rate at ratios above 14.15±0.17 up to 24.08±0.22 gCODgN-1. 

Chitosan, is a biodegradable cationic polymer, which is derived from deacetylation of chitin. The present study was conducted to investigate the effect of chitosan as a coagulant aids in improving the performance of coagulant property of poly-aluminum chloride as a primary coagulant on the removal of turbidity from water.This study, was performed in a laboratory scale and using jar test apparatus in Ahwaz Water Treatment Plant.Experiments were performed with different concentrations of coagulants, pH and different concentrations of chitosan as a coagulant aids. First the samples mixed under rapid mixing condition (120rpm) for 1minute and then the apparatus set to slow mixing (40rpm) for 20 minute. After mixing the samples left for 30 minute in order to settle the sediments. The optimum pH was found 8 in this study. The optimum doses of poly-aluminum chloride in conjunction with chitosan, were 5mg/L and 0.02 mg/L, respectively. The required dosage of polyaluminum chloride as a primary coagulant be reduced upto 50% under optimum condition with chitosan. It was also found using chitosan also produced larger floc with higher settling velocity than primary coagulant alone.The results also showed that chitosan as a coagulant aid had a positive effect on turbidity removal.

The presence of heavy metals in the environment due to their harmful effects on human health, regarded as a problem. Today, high-performance biosorbents for wastewater treatment containing heavy metals such as cadmium were developed and are preferable than other absorbents. The aim of this study was investigation of effect of influent concentration on cadmium removal in a fixedbed column using adsorbent Conocarpus. Conocarpus was prepared from waste vegetable of DEHLORAN city gardens and surface structure of absorbent was investigated. In this study, the effect of influent concentration on cadmium removal was investigated and Adams-Bohart and Thomas models were used to the column adsorption modeling. Physical characteristics results showed that the adsorbent has deep pores and complex, intricate, uneven and irregular surface of filamentary structure. The results of breakthrough curves review showed that in higher concentrations, breakthrough time of bed was decreased. breakthrough curves slope increased and breakthrough volume decreased with increasing initial cadmium concentration. Also Adams-Bohart model has a better fit of the column data.

This study investigated the occurrence and removal of 12 antibiotics (ciprofloxacin, enrofloxacin, levofloxacin, norfloxacin, nalidixic acid, azithromycin, clarithromycin, roxithromycin, lincomycin, novobiocin, sulfamethoxazole, trimethoprim) at four sewage treatment plants (STPs): two STPs in Kyoto, Japan and two STPs in Beijing, China. The STPs differed in design and operation conditions, utilized a variety of secondary treatment processes. The antibiotics were frequently detected in influents and effluents, and ranged from ng/L up to lower mg/L. In influent, clarithromycin (1.1–1.6 mg/L) and levofloxacin (3.6–6.8 mg/L) were detected in the highest concentration in Japanese and Chinese STPs, respectively. The overall elimination of the antibiotics were differed between STPs and ranged from negative to>90%. These data demonstrate that there are detectable levels of antibiotics are discharging from STPs, and only some of these antibiotics are being removed in a significant proportion by STPs. It was also observed that biological nutrient removal based sewage treatment processes (anaerobic– anoxic–oxic: A2O; and anoxic–oxic: AO) have relatively higher antibiotics removal efficiencies than oxidation ditch (OD) processes.

Progressive collapse studies generally assess the performance of the structure under gravity and blast loads, while earthquakes may also lead to the progressive collapse of a damaged structure. In this study, the progressive collapse response of concentrically braced dual systems with steel moment-resisting frames was assessed under seismic loads through pushover analysis using triangular and uniform lateral load patterns. Two different bracing types (X and inverted V braces) were considered, and their performances were compared under different lateral load patterns using the nonlinear static alternate path method recommended in the Unified Facilities Criteria (UFC) guideline. Eventually, the seismic progressive collapse resistance of models was compared to their progressive collapse response under gravity loads. These studies showed that models under the seismic progressive collapse loads satisfied UFC acceptance criteria and limited rehabilitation objective. The structures had better performance under seismic progressive collapse than models under gravity loads because of more resistance, ductility, suitable load redistribution, and more structural elements that participated in load redistribution. Furthermore, despite studies on progressive collapse under gravity loads, the dual system with X braces showed better progressive collapse performance (more resistance, residual reserve strength ratio and ductility) under seismic loads than the model with inverted V braces.