Sharif Digital Repository

Distilleries wastewater is an important environmental problem due to its high BOD and COD content, and toxic materials such as phenolic compounds, and low pH. Direct and continuous discharge of this effluent to the soil reduces the quality of soil and destroys agricultural crops. In addition, its discharge to rivers and sea will seriously affect aquatic life. In order to prevent environmental hazards, a number of biological, chemical and physical methods have been introduced for treatment of this wastewater. Chemical and physical methods are based on surface sorption, ion exchange, membrane processes and chemical oxidations. In biological methods, anaerobic processes are more economical than... 

Pilot Moving Bed Biofilm Reactors (MBBRs) fed on synthetic wastewater, were used in order to study nitrification and denitrification of high concentration wastewater. To investigate the stability of the nitrification and denitrification process in moving bed biofilm systems, a hydraulic shock and a toxic shock were applied to the system. These two systems showed high stability and process efficiency did not change significantly, in spite of intensive variation during the applied shocks  

In this paper, a modified activated sludge process using a Fixed Film Aeration Tank (FFAT) was investigated as an improvement for the usual activated sludge or trickling filtration processes. The aeration tank of the system was arranged with fixed parallel saran nets, which were set vertically as supporting media for microbial growth. A carbonaceous solution was brought into contact with microorganisms in the media and was oxidized aerobically. Filamentous microorganisms predominantly grew on the films and the COD removal increased with the increase in accumulated biomass in the system. Simulation of treatment performance in the system was carried out using mathematical models. The... 

The aim of this study is to quantify the water-energy-emissions nexus in wastewater treatment plants (WWTPs). At first, energy auditing is done for two real WWTPs to find out the energy consumption of different plant stages and the energy-saving potentials. The power plant and carbon capture units are taken into account to assess the energy-emission nexus based on emergy flows. Then, the emergy analysis is applied to evaluate the environmental, economic and technical aspects. An emergy performance index (EmIGHG) is presented by the means of emergy flow diagram of the WWTP beside a power plant (considering the electricity production emergy cost) and carbon capture unit (considering the CO2... 

This study aimed to evaluate and compare the performance of wastewater disinfection systems using ultraviolet radiation (UV) and ozonation to improve the secondary effluent quality of Isfahan North wastewater treatment plant. Therefore, the filtered effluent by a pretreatment unit from micro-screen drum filter type with a pore size of 20 µm entered the disinfection pilots containing medium pressure (MP) UV lamps and ozonation system as tertiary treatment. In this study, the irradiation dose of UV (430–3,680 mW/cm2), and injection dose (10–40 mg/L), and contact time (1–15 min) of ozonation were altered. The results showed that the total suspended solids were reduced by 61.27% at the maximum... 

In this research FeCl2/FeCl3/Perlite magnetic nanoparticles (FeCl2/FeCl3/PMNs), as a novel magnetic nanocomposite adsorbent was used for the removal of green malachite (GM) dye from aqueous solution in a batch and fixed bed column. Firstly, FeCl2/FeCl3/PMNs adsorption properties were investigated. Therefore, the solution of FeCl2·4H2O and FeCl3·6H2O by ratio 2/1 was mixed with perlite nanoparticles. The study investigates the effect of process parameters such as pH, adsorbent dosage, contact time and GM dye initial concentration. Next, GM dye was quantitatively evaluated by using the Langmuir, Freundlich and BET isotherms and pseudo-first- and pseudo-second-order kinetic model. The... 

Conventional wastewater treatment systems demand a high cost mechanical aeration. Using algal-bacterial systems helps to reach a cost-efficient treatment method by eliminating mechanical aeration, since algae produce the oxygen needed for treatment process. In this study, two groups of experiments were performed for domestic wastewater treatment processes. For the first group, semi-continuous microalgae-bacterial photo-bioreactors were cultivated. Chlorella Vulgaris and activated sludge (AS) were used as microalgae and bacterial inoculums, respectively. The effect of different algae and AS ratios on the chemical oxygen demand (COD), N-NH4 + and P-PO4 3− removal was studied. The removal... 

This study is focused on simulating and optimizing design and configuration of anaerobic baffled reactor (ABR) by means of artificial neural network (ANN). This approach is aimed to assess an efficient ABR performance in various operational conditions treating municipal wastewater. For this purpose, to analyze comprehensively on a base of experimental data, the system is operated in two pilots of 48 liters net volume made of 8 compartments. In 7 months, more than 130 sets of data are obtained to be introduced to MATLAB neural network. These include removal efficiency of chemical oxidation demand (COD) and volatile fatty acids (VFAs) parameters. The finest correlative architecture obtained... 

The influence of particle size and surface modification on sonocatalytic activity of TiO2 nanoparticles was investigated by measuring the degradation efficiency of methyl orange (MO) as a model pollutant. Crystalline TiO2 nanoparticles with different particles and aggregate size were prepared through solution-phase method with varying synthesis temperatures. Coating with polyvinyl alcohol was performed to enhance colloidal stability of the particles over a wide range of pH values (1.5–7.5). Characterization was carried out using X-ray diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and Fourier-transformed infrared techniques. It was found that... 

The main objective of this study was to compare the removal efficiency of nutrients using Lactuca sativa, Medicago sativa and Phragmites australis in subsurface flow constructed wetlands with horizontal flow. In order to test water quality, fabricated reactors designed and the plants cultivated in the soil while their root were inside the wastewater. A long time study carried out from spring till end of autumn (9 months) in order to evaluate the difference in removal rate based on the seasonal changes. The highest removal rate was during summer which followed by spring and autumn. Thus, the effect of plants on the removal efficiency of organic matter (COD, BOD), TSS and nutrient (P and TN)... 

A new multifunctional filtration membrane was prepared by twofold advantages of conventional polymeric-membrane as the supporting layer and magneto-plasmonic Ag-doped ZnO@Fe3O4/MWCNTs nanocomposite as the functional layer. Poly acrylic acid (PAA)-modified polyamide (PA) discs (PAA-PA) were applied to increase the hydrophilicity of prepared membrane and X-Ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used for characterization. The grafting yield of PAA in the pores and on the surface of PA was 17 wt.% and weigh difference between PAA-PA membrane before and after modifying with the photocatalyst was 8.7 mg. The amount of photocatalyst loading in the prepared... 

Disposal of contaminated wastewater causes many serious problems especially when it gets mixed with the ground and seawater. It is, therefore, important to apply any remedial action to eradicate dangerous pollutants from the aqueous effluents and to avoid exposure of this wastewater to aquatic life. The research results discussed herein deal with the removal of Rhodamine B (RhB) and Congo Red (CR) dye from wastewater by using multi-walled carbon nanotubes (MWCNTs) as an adsorbent. Different factors like solid dosage, initial pH and concentration, time, and temperature were studied to understand the behavior and mechanism of adsorption. The maximum adsorption capacity in case of a single... 

The purpose of this study was to investigate the use of a horizontal packed bed bioreactor, named Biopack, to treat high strength wastewater, such as bakers yeast wastewater. The Biopack system (RBCP) is a modified rotating biological contactor and the system was applied for secondary treatment. The RBCP system produced high treatment efficiencies, COD removal was 94.9% when COD was 472 mg/l and surface organic loading = 0.187 kg COD/m2 per day and surface hydraulic loading = 6 l/m2 per day. Variations of surface hydraulic loading from 6 to 11.9 l/m2 per day produced a decrease in COD removal efficiency from 94.9 to 58.6%. Other factors, such as shock load, retention time and rotational... 

Discharging unconventional water sources having a high content of inorganic compounds is extremely destructive to the environment. In this research, four novel semi-open-air and closed-air configurations of brine-recycle humidification-dehumidification (BRHDH) systems with zero liquid discharge (ZLD) approach are presented to treat unconventional waters cost-effectively. Bubble-column humidifiers and dehumidifiers are used to have a low initial expenditure, and system multi-staging is implemented to reduce the operating expense of the configurations. The configurations are evaluated for high saline brine treatment using comprehensive energy, exergy, exergoeconomic, and exergoenvironmental... 

Rotating dissolved air flotation (RDAF) has been utilized for several decades in paper-recycling wastewater treatment; however, it has rarely been addressed in the literature, which makes research into this system challenging and complicated. However, in this work, a full-scale industrial wastewater treatment system for a paper-recycling mill in Mazandaran province, Iran, was evaluated. Experiments indicated that under the same wastewater and chemical conditions, there are differences in the removal efficiencies. This finding was investigated by conducting simulation in ANSYS CFX R18.0 and experimentation simultaneously. Thus, the main purpose of this research was to optimize the operation... 

In this paper, copper oxide nanoparticle was synthesized, and its surface was modified using N-(2-aminoethyl)-3-(trimethoxysilyl)propylamine. The bi-amino surface functionalized nanoparticle (BASFN) was used to remove anionic dyes from single and binary systems. The scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDAX) and X-ray diffraction were used to characterize the nanoparticle. Direct Red 80 (DR80) and Direct Green 6 (DG6) were used as anionic dyes. The effect of adsorbent dosage, dye concentration and pH on dye removal was evaluated. Kinetic of dye adsorption on BASFN followed pseudo-second order. The results...