Journal of Applied Research in Water and Wastewater
Volume:8 Issue: 1, Winter-Spring 2021

In the current study, a new hybrid of the genetic algorithm (GA) and adaptive Neuro-fuzzy inference system (ANFIS) was introduced to model the discharge coefficient (DC) of triangular weirs. The genetic algorithm was implemented for increasing the efficiency of ANFIS by adjusting membership functions as well as minimizing error values. To evaluate the proficiency of the proposed hybrid method, the Monte Carlo simulations (MCS) and the k-fold validation method (k=5) was applied. The results of developed hybrid model indicate that the weir vortex angle, flow Froude number, the ratio of the weir length to its height, the ratio of the channel width to the weir length and ratio of the flow head to the weir height are the most effective parameters in the DC estimation. The quantitative examination of the proposed hybrid method indicates that the Root Mean Square Error (RMSE) and Mean Absolute Percent Error (MAPE) are as 0.016 and 1.647 (respectively) for the superior model. Besides, the Froude number is found as the most effective variable in DC modeling through the quantitative analysis. A comparison of the developed hybrid ANFIS-GA with the individual ANFIS model in the DC estimation indicates the hybrid model outperformed than the individual one.

The improper operation performance of many irrigation channel is nearly a result of the lack in understanding transient flow phenomena due to the implementation of water delivery in the irrigation canal. Travel and response time are the most important characteristics of unsteady flow in open canal affecting the operation performance. Solving the Saint Venant equation and using hydrodynamic models is usual method to assess the response and travel time, but limited access and the complexity of the application of those caused to introduce simple methods for calculating them. Two analytical methods introduce to determine the travel and response time. The diffusion wave approximation and gravity wave can be used for the travel time and the diffusion wave and Ankum’s formula are used for the response time. In this study, the travel and response time has calculated using HEC-RAS and compared in approximate methods. The results show that the gravity wave is used to determine the travel time for short canal and the diffusion wave method is suitable for long canal reaches. In BLMC channel, the average response time error to distance of 3000 meters for Ankum’s formula is 5.1 percent, and the error of diffusion wave model is 5.5 percent from 3000 meters to the end of the canal. In this study, the effect of variation in input discharge on travel and response time are investigated. It has effect on travel and response less than 3 % and 5 %, respectively.

In recent years, the growing population and the need to supply water for domestic, and health, and agriculture sectors have led to the establishment of industrial centers in developing countries. The onset of drought in most countries has challenged surface water, groundwater, dams, and reservoirs. Iran is among those countries, which is located in a dry and semi-arid region.  These factors made managers and decision-makers in this field make appropriate rules and regulations for the use of limited water resources. In this paper, the Vensim dynamic model was applied to properly exploit the Yamchi Dam water and groundwater resources in the Ardabil plain in Iran and allocate these resources in the agriculture, industry, and drinking sectors. By defining different scenarios, it was found that pressurized irrigation and changing the crop pattern scenarios are the most appropriate options for water management in the Yamchi basin. In this scenario, known as G in the model, 62% of the network lands are moved from traditional flood to pressurized irrigation with an irrigation efficiency of 60%. Accordingly, the reliability of the agricultural and drinking water supply will reach 92 and 99%, respectively. Meanwhile, due to saving the water resources, the water infiltration caused by irrigation will be greatly reduced, and the land swamping will be prevented.

Rivers are one of the primary water resources for agricultural, drinking, industrial and environmental applications; thus, assessment of the river water quality has a great significance. This study aims to evaluate the self-purification capacity of the Haraz river and identify critical areas with the lack of dissolved oxygen along the river. Also, the QUAL2K model, IRWQI and NSFWQI indexes were applied for the determination of water quality. In this study, primary pollutant sources including urban areas, industrial centers, farmlands and multiple cold-water fish farms that their water usage and discharge have severe consequences on the quality and quantity of the river's stream were identified and located. This model was built and calibrated for four seasons with data from six sampling stations of Haraz river. Based on this study, upstream of Haraz river has adequate self-purification capacity in comparison to its midstream and downstream, especially in the Amol city area, lack of dissolved oxygen was observed and self-purification capacity considerably reduced. The critical areas of Haraz river in spring and winter seasons are downstream and the estuary region, while in summer and autumn, critical areas are increased in Amol city. In general, as the elevation decreases, the water quality decreases. Only in upstream areas (near the Poloor village and before the Chelav station), water quality is in the average condition, but near the Caspian sea, the condition of Haraz river is worrying due to the existence of contamination sources.

In recent years, water scarcity has posed significant challenges to oil refineries. The escalating water demands of developing oil refineries in pace with the progressively stringent environmental, economic, and technical regulatory and suitability constraints necessitate seeking sustainable water and wastewater management strategies that encourage minimizing fresh water consumption through treated wastewater reuse. Thus, the main scope of the present study is to investigate a general procedure using innovative post treatment technologies in order to attain an almost zero discharge water management in real life - Kermanshah's oil refinery case study. The results obtained are proofs enough that the selected post treatment scenario can effectively minimize the overall fresh water demand.

In photocatalytic microreactors the catalyst layer is obtained by integration of nanostructure films of semiconductors. One of these nanostructures that have a good photocatalytic activity is ZnO nanowires. The photocatalytic degradation of methylene blue in a continuous flow microreactor with ZnO nanowires deposited film is simulated. A finite element model is developed using COMSOL Multiphysics version 5.3 software to simulate the microreactor performance. The kinetic law of the photocatalytic reaction is assumed to be Langmuir–Hinshelwood. The kinetic constants kLHa and K are determined 1.43×10-7 mol/m2s and 7.5 m3/mol, respectively. The percent of average absolute deviation of the model in predicting the methylene blue outlet concentration obtained about 0.12% mol/m3. The model showed a very good agreement with the published experimental data. The effect of microreactor depth, methylene blue inlet concentration and flow rate on the methylene blue degradation is also investigated. The simulation results showed that the microreactor with shorter depth and lower values of inlet concentration and flow rate has higher efficiency. Thiele modulus and Damköhler number are both estimated lower than 1. It indicates that the photocatalytic reactions occur without internal and bulk mass transfer limitations.

The purpose of this study was numerical and experimental investigations on the influence of ultrasound on Cr (VI) removal from aqueous solution by adsorption onto activated carbon nanoparticles. The effect of key factors on Cr (VI) elimination like media pH, absorbent mass, initial concentration of Cr (VI) and the location of ultrasound transducers were considered. To perform CFD modeling of ultrasound propagation, the vibrations of 1.7 MHz piezoelectric transducers (PZTs) were defined based on the dynamic mesh model. The experimental results indicated that by pH raising from 2 to 8, Cr (VI) removal efficiency had a decreasing trend and at pH=8, it had the lowest value. The adsorption rate increased by augmentation in the adsorbent mass (AM) due to the enhancing its specific surface area. In comparison with using a shaker, ultrasound showed lower needed contact time for Cr (VI) elimination at identical conditions. In addition, CFD results depicted that the acoustic streams were induced in the direction of ultrasound propagation, which is caused to reach the better mixing and Cr (VI) removal efficiency. Finally, the experimental data were adopted with the Langmuir and Freundlich isotherms. The comparison of these models showed that both models were well suited to experimental findings and the data compatibility with Langmuir model was greater.

Disposal of waste products and residuals into the natural water bodies can havefatal consequences for aquatic ecosystems, posing severe threats to naturalhabitats and human health. Natural treatment systems are the most suitabletreatment technologies for various types of wastewaters, which has attracted muchattention in recent years. Phytoremediation is a plant-based technique used toeliminate or recover surplus nutrients in contaminated environments. The use ofaquatic plants in wastewater phytoremediation is very efficient due to they have avery significant ability for assimilating and degrading contaminants (e.g., nitrates,phosphates, and heavy metals). Phytoremediation is a relatively new technologythat is considered as an operational, efficient, new, and environmentally friendlytechnology that is still in the early stages of development and optimization. Itsapplication on a large scale is still limited. It should also be noted that a clear visionof this innovation should be taken into account and, accurate data should be madeavailable to the public as it will enhance its efficiency as a manageable solution inthe worldwide. Additionally, phytoremediation has been evaluated as a separatelow-tech and environmentally friendly green option compared to the existingtechnologies. The present study attempts to review the recently published literatureto explain phytoremediation technology and its advantages in purifying water andwastewater.

Healthcare facilities are vital establishments to improve the public health, but with poor waste and wastewater management, may turn into a potential health risk. The fecal-oraltransmission potential of SARS-CoV-2 and the role of the wastewater as a potential sourceof infection, more than ever highlights the importance of proper wastewater managementduring the COVID-19 pandemic. This systematic review represents a picture of the currentstate of hospital wastewater (HWW) management in Iran; an upper-middle income countrywith a paucity of proper data concerning HWW management and further provides suggestions for hospital wastewater management during COVID-19 pandemic in the country. We reviewed 31 papers that published from 2005-2020 evaluated 163 hospitals from 82 cities and 17 provinces. HWW generation in Iran varies from 354 to 1892 liter per bed per day (839±363 L/bed/d). BOD, COD and TSS in the raw HWW were in the range of 119-1270, 205-1611 and 58-464 mg/L, respectively. Total coliforms and/or total fecal coliforms were in the range of 105-108 (MPN/100 mL). 44.2 % of hospitals had an active WWTP at the time of the study from which, only 15.3 % complied with discharge standards. More than 55 % of the hospitals in Iran use no disinfection, and less than 7 % comply with the discharge requirements. HWW management in Iran is very poor and there has been no improvement in HWW management within the last decade. To best respond to this pandemic, responsible authorities should address wastewater management in hospitals.

Presently, Pakistan is the 8th largest exporter of textile products in the world andthis sector is considered the backbone of Pakistan’s economy. Due to intensifieduse of dyes, chemicals, and water, the textile sector is also listed as the highestcontributor to environmental pollution. Therefore, to approach the demand of newglobal trend towards sustainability, the textile industry along with others need tofocus on resource recovery and reuse. The present study was therefore plannedfor the treatment of textile effluent composed from 04 textile mill samples. Thetextile effluent is treated by employing coagulation, ozone oxidation, andultrafiltration techniques. All the samples exceeded the standard limits as given inSindh Environmental Quality Standard (SEQS 2016). Each individual treatmentprovided promising results in terms of reduction in pollution load. Overall findingsrevealed a remarkable decrease in total suspended solid (TSS) (96 %), totaldissolved solid (TDS) (78 %), chemical oxygen demand (COD) (93 %), BiologicalOxygen Demand-BOD (93 %), oil & grease (96 %) and heavy metals (HM) (98 %).It is suggested that combined techniques are the best option for textile effluenttreatment.

The objective of this study was to evaluate the coagulation-flocculation process inthe clarification of leachate from the landfill Technical Center of Souk-Ahras cityusing three coagulants based on iron: ferrous sulfate FeSO4.7H2O; ferrous chlorideFeCl2.4H2O and ferric chloride FeCl3. The influence of some parameters namelypH leachate, dose and nature of coagulant and nature of flocculant was studied.The best treatment efficiency was obtained at 20 % of FeCl3 giving a turbidity of4.09 NTU with pH adjustment of the raw leachate at acidic pH (3.5 ± 0.2) beforecoagulant addition and at a basic pH (7.5 ± 0.2) after addition of coagulant. Theiron valence and the nature of anion at which is linked, played a determinant rolein the clarification of leachate. The treatments made with ferric chloride in thepresence of a flocculant have proved that the starch was more efficient than limegiving abatement rates of 99 % for COD and 85 % for BOD5.

As a result of population growth and potable water scarcity, an increasing number of reverse osmosis desalination plants are being installed and operated (more than 15,000 in the world). Reverse osmosis membranes tend to reach the end of the life cycle in around two to five years, becoming a solid waste. Recycling/repurposing these aged membranes could be a sustainable and profitable solution. This project aimed to transform end-of-life reverse osmosis membranes through the oxidation of their active layer using chlorine into nanoporous/microporous membranes, while searching possible applications for the resulting membranes. The results show that membranes oxidized at 10,000 ppm.h had a significant increase in permeability (3.1x), reaching NF-like capacity. On the other hand it was observed a decrease in the rejection of salt (4.35x) and acetaminophen (1.5x). Scanning Electron Microscopy (SEM) shows the positive effect of chlorine in the complete removal of particles deposited over the membrane. This oxidation condition also increased the average roughness (2.42x) of the membrane, as shown by Atomic Force Microscopy (AFM). Analysis by Fourier Transform Reflectance Spectroscopy (FTIR) suggests that chlorine oxidation replaced the hydrogen in the amide nitrogen. Both FTIR and SEM suggests the polyamide layer was not fully degraded. Application tests suggests that the recycled membrane can be used for the treatment of brackish and surface waters. The recycling of reverse osmosis membranes can be an alternative to simple landfill disposal, allowing owners to shift from disposal cost to revenue, as well as being a sustainable solution. The high permeability achieved on these oxidized membranes suggest many other NF/UF functions could potentially use recycled RO membranes.