The effect of hydraulic jump on the aeration efficiency

One of the most important parameters to determine the quality of water is the amount of the dissolved oxygen (DO) in water body. Microorganisms as bacteria need high concentration of oxygen in water to the able to continue their lives healthfully. In this case, the concentration of the dissolved oxygen in water body should be greater than 5 mg/L. The hydraulic jump is used as an effective natural mechanic mixer for the oxygen transfer from air to water body. This study is aimed to investigate the aeration efficiency created by the water jet vertically on the turbulence shear layer in hydraulic jump. The experiments have been realized in an open channel having a width of 0.4 meters, a height of 0.65 meters and a length of 12 meters. The dissolved oxygen has been measured using by a DO200 hand type oxygen meter. Experiments are taken account five different jet flow rates and Froude numbers with in the range of 1 Fr = 3.55-6.07 in the study

Students' Reluctance to Attend Office Hours: Reasons and Suggested Solutions

This paper focuses on investigating students’ reasons for their reluctance to attend faculty members’ office hours. Study participants included 500 male and female students from the Colleges of Engineering (n = 248) and Arts and Social Sciences (CASS) (n = 252) at Sultan Qaboos University (SQU). The study followed a descriptive-analytical approach, and a questionnaire was utilized to collect people’s views. The results of the study indicate that the rates of SQU students’ attendance to office hours were low, and some students (11.2%) do not attend at all as they consider these office hours a waste of time. The main reasons behind the students’ lack of interest in office hours were busy student timetables, conflicts between faculty office hours and students’ timetables, and easier and faster ways of getting information than visiting faculty members. Additional reasons were related to faculty members’ personalities and their discouraging attitudes toward attending office hours. The researchers recommend that SQU adopt a new strategy for encouraging faculty members to hold office hours, familiarizing students with the importance of office hours and assigning part of a course’s grades to meeting with faculty members’ office hours

A mini literature review on sustainable management of poultry abattoir wastes

Poultry slaughtering and post-processing activities generate different kinds of highly perishable organic wastes and by-products. Poultry carcass yields are typically about 70-75% of the live bird weight, the rest is accepted as inedible waste. Depending on the efficiency of the processing methods birds' blood, feather, head, feet, offal and inedible viscera, and in some cases, treated solids make up the slaughterhouse solids in the poultry industry. The management of nutritive organic waste should aim to produce value-added by-products such as pet animal or aquaculture feed components, energy through thermochemical or biochemical processes, and agricultural fertilizer. Conventional rendering at specified temperatures and pressures are widespread processing and well-established methods to produce sellable products in the form of protein-rich meals such as poultry powder, feather powder, and fat. The utilization of raw or processed poultry by-products for animal feed is become strictly banned in both national and international scales for the poultry industry. There has been increasing stress to find alternative areas demanding nutrient-rich solid by-products. The objective of this study is to review several studies with a special focus on poultry abattoir-related activities to draw attention to proper management practices from the environmental point of view. The review shows that best management of the process, high-quality wastes need further innovative and effective processing methods to find possible feed additive either for fish or other animal meal, as well as alternative waste treatment process that provides an opportunity for energy recovery and high-quality bio-nutrient source to be used for crop production

A Hybrid Fuzzy AHP-TOPSIS Approach for Implementation of Smart Sustainable Waste Management Strategies

The integration of smart city technologies into waste management is a challenging field for decision makers due to its multivariate, multi-limiting, and multi-stakeholder structure, despite its contribution to the ecological and economic sustainability understanding of cities. The success of smart sustainable waste management strategies depends on many environmental, technical, economic, and social variables, and many stakeholders are involved in these processes. Using fuzzy multi-criteria decision-making (MCDM) methods helps decision makers determine effective, affordable, and acceptable smart waste management strategies. Although MCDM methods are widely used in various environmental engineering applications, the determination of smart sustainable waste management strategies using these methods has not yet received enough attention in the literature. This study aims to contribute to this gap in the literature by evaluating four different smart waste management strategies using a hybrid fuzzy MCDM method. The performance of the proposed strategy alternatives according to fifteen sub-criteria (under four main criteria selected from the literature) was evaluated using a combined application of fuzzy analytic hierarchy process (fuzzy AHP) and fuzzy technique for order preference by similarity to obtain the ideal solution (fuzzy TOPSIS). For this evaluation, the subjective opinions of ten different experts working in academia, in the private sector, or in the public sector were obtained using prepared questionnaires. As a result, the sub-criteria of fewer atmospheric emissions (0.42), operational feasibility (0.64), initial investment costs (0.56), and increased awareness of sustainable cities (0.53) had the highest weight values in their main criteria groups. The performance ranking of the alternatives according to the closeness coefficient (CCi) values was obtained as A2 (0.458) > A3 (0.453) > A4 (0.452) > A1 (0.440), with A3 being slightly ahead of A4 due only to a 0.001 higher CCi value. To test the reliability and stability of the obtained performance ranking results, a sensitivity analysis was also performed using eighteen different scenarios, in which the weights of the different sub-criteria were increased by 25% or decreased by 50%, or they were assumed to be 1 and 0, or all sub-criteria in the same group had equal weight values. Since the performance ranking of the alternatives did not change, the ranking obtained at the beginning was found to be robust against the sub-criterion weight changes

Evaluation of anaerobic biodegradability potential and comparative kinetics of different agro-industrial substrates using a new hybrid computational coding scheme

*Çetinkaya, Afşin Yusuf ( Aksaray, Yazar )The present analysis was conducted as the first study to investigate the biochemical methane potential of four different agro-industrial wastewaters originating from chocolate, slaughterhouse, gum, and beet sugar industries under the same anaerobic fermentation conditions. To the best of our knowledge, no previous study has specifically attempted to pinpoint a hybrid programming strategy for making a quantitative description of the anaerobic biodegradability of these waste streams. Thus, considering the scarcity of the literature in this field, a comprehensive study was conducted to evaluate the amount of bio-methane obtainable from the investigated organic wastes and to predict their kinetics using three different sigmoidal microbial growth curve models (modified Gompertz equation, transference function (reaction curve-type model), and logistic function) within the framework an original MATLAB®-based coding scheme. The results showed that methane productions started immediately after 4 h of incubation for all substrates and reached their maximum rates of 118, 116, 108, 34 mL CH4/g VS/day, respectively, for wastewaters from chocolate, slaughterhouse, gum, and beet sugar industries. The corrected mean steady state methane contents were 61.7%, 73.4%, 62.8%, and 62.1% in the respective order. The highest methane yield (943 mL CH4/g VS) was obtained from the slaughterhouse wastewater, and this value was 1.32, 1.58, and 4.56 times higher than those obtained in the anaerobic digestion of chocolate, gum, and beet sugar wastewaters, respectively. Among the three kinetic models tested, the logistic function best explained the behavior of the observed data of all substrates using a Quasi-Newton cubic line search procedure (R2 ¼ 0.987e0.996) with minimum number of non-linear iterations and function counts. Deviations between the measured and the outputs of the best-fit kinetic model were less than 4.3% in prediction of methane production potentials, suggesting that the proposed computational methodology could be used as a well-suited and robust approach for modeling and optimization of a highly non-linear biosystem...

Treatability of high-strength real sheep slaughterhouse wastewater using struvite precipitation coupled Fenton's oxidation: The MAPFOX process

Struvite (MAP, magnesium ammonium phosphate hexahydrate, MgNH4PO4.6H2O) precipitation-aided Fenton's OXidation (MAPFOX process) was explored in the treatment of high-strength real sheep slaughterhouse wastewater (RSSW) for the first time under a comprehensive soft-computing-based modeling study. The experimental results showed that under the highest-efficiency conditions (chemical combination of MgCl2.6H2O + NaH2PO4.2H2O, a molar ratio of Mg2+:NH4+-N:PO43–P = 1.2:1:1, a reaction pH of 9.0 ± 0.10, [NH4+-N]0 = 240 ± 20 mg/L, and a reaction time of 15 min), MAP precipitation could effectively remove more than 80 %, 60 %, 55 %, and 70 % of color, total chemical oxygen demand (TCOD), soluble COD (SCOD), and ammonium nitrogen (NH4+-N) from the raw RSSW. The results of the Fenton's oxidation used as the post-treatment unit of the proposed MAPFOX system indicated that the integrated advanced oxidation process (AOP) was able to reduce the residual pollutant levels in the MAP-pretreated RSSW to the relevant discharge standards. Under the subsequent condition of [Fe2+]0 = 90 mmol/L, [H2O2]0 = 180 mmol/L, reaction pH = 3.25, and total reaction time = 60 min, more than 97 % of color, TCOD, SCOD, and NH4+-N could be removed from the RSSW via the Fenton's oxidation after the MAP-based physicochemical treatment. According to SEM micrographs, surface morphology of dehydrated struvite exhibited irregular-shaped and overlapping sharp-edged particles of various sizes with an average size of about 50.9 μm. The Fourier Transform Infrared (FTIR) spectroscopy confirmed the active functional groups and type of bonds for the high-strength RSSW-oriented struvite (heated) within the spectral range of 4000–450 cm−1. Thermogravimetric Analysis (TGA), Derivative Thermogravimetry (DTG), Differential Thermal Analysis (DTA), and Differential Scanning Calorimetry (DSC) of the dehydrated struvite revealed that the weight loss occurred in three temperature zones, the maximum weight loss rate of 0.252 mg/min was recorded at around 224 °C and at time of 20.83 min, and the sample had strong endothermic and medium exothermic peaks at about 241 °C and 679 °C, respectively. The predictive successes of the implemented soft-computing approaches were benchmarked in terms of various statistical goodness-of-fit parameters. The performance assessment indices corroborated the superiority of the support vector machines-Pearson VII universal kernel function (SVM-PUKF)-based model (correlation coefficient (CC) = 0.9999–1.0000), mean absolute error (MAE) = 0.0222–0.0389 %, mean absolute percentage error (MAPE) = 0.0270–0.0506 %, root mean squared error (RMSE) = 0.0258–0.0415 %, coefficient of variation of RMSE (CV(RMSE) = 0.0003–0.0008, Nash–Sutcliffe efficiency (NSE) = 0.9998–1.000, Legates and McCabe's index (LMI) = 0.9894–0.9952) over other data-intelligent models in predicting the pollutant removal efficiencies. The computational results also indicated that the narrowest uncertainty bands (±1.96Se = 0.0537–0.1483 %) and the lowest amounts of expanded uncertainty (U95 = 3.1224–5.3124 %) values for all efficiency sets were achieved for the applied SVM-PUKF-based strategy. This study demonstrated the first-ever and successful application of the proposed MAPFOX process in treatability of the RSSW and capability of the implemented soft-computing strategy in modeling a highly nonlinear treatment system

Application of solarization for sanitization of sewage sludge compost

Performance of the solarization process on inactivation of pathogenic bacteria was explored to provide the sanitization standards set for the sewage sludge compost. For evaluation of the microbiological quality of sludge compost and the sanitation efficiency of solar application, Escherichia coli, thermotolerant coliforms, Clostridium, and Enterococci were selected as the indicator microorganisms. Unsolarized (control) treatment was conducted at room temperature (25 +/- 2 degrees C) in laboratory conditions. Solarization treatment was performed under heating conditions, where the sufficient ultraviolet radiation was directly provided by sun. The results indicated that solarization remarkably increased the temperature of sludge compost to maximum 65 degrees C at 5 cm of compost depth. The inactivation rates of indicator microorganisms exposed to the solarization treatment were recorded significantly higher than the unsolarized treatment. Among the indicator microbial agents, E. coli was found as the most susceptible microorganism and lowered from 4 log CFU g(-1) to undetectable levels after 6 days of solarization process. However, the reduction rate of the unsolarized group of this bacteria was determined to be less than the 1-log within 15 days of the entire experimental period. For the solarized compost, the viability of Enterococci ranged from 2.31 log CFU g(-1) to 1.80 log CFU g(-1) within 6 days and reduced to below the detection limit (2 x 10(1) cells as CFU) after 12 days of solar application. The reduction rates of thermotolerant coliforms and Enterococci were slow (k(max) = 3.22 and 3.27 day(-1), respectively), but they were reduced to below the detection limit within 12-15 days. The inactivation curves demonstrated that Clostridium showed more resistance to heat provided by solarization compared with other indicator microorganism species. The Clostridium reduction in solarized treatment was determined as 3-log, while the unsolarization treatment provided 0.7-log reduction. Findings of this study clearly corroborated that the temperature profile generated by the solarization process was adequate for elimination and/or inactivation of various microbial pathogens to achieve the desired standards within two weeks. (C) 2018 The Authors. Production and hosting by Elsevier B.V