Behzad Shahmoradi

Simultaneous nitrification-denitrification and phosphorus removal in a fixed bed sequencing batch reactor (FBSBR).

Biological nutrient removal (BNR) was investigated in a fixed bed sequencing batch reactor (FBSBR) in which instead of activated sludge polypropylene carriers were used. The FBSBR performance on carbon and nitrogen removal at different loading rates was significant. COD, TN, and phosphorus removal efficiencies were at range of 90-96%, 60-88%, and 76-90% respectively while these values at SBR reactor were 85-95%, 38-60%, and 20-79% respectively. These results show that the simultaneous nitrification-denitrification (SND) is significantly higher than conventional SBR reactor. The higher total phosphorus (TP) removal in FBSBR correlates with oxygen gradient in biofilm layer. The influence of fixed media on biomass production yield was assessed by monitoring the MLSS concentrations versus COD removal for both reactors and results revealed that the sludge production yield (Y(obs)) is significantly less in FBSBR reactors compared with SBR reactor. The FBSBR was more efficient in SND and phosphorus removal. Moreover, it produced less excess sludge but higher in nutrient content and stabilization ratio (less VSS/TSS ratio).

Collection of municipal solid waste in developing countries

apparent divide also in the Coalition Government at Secretary of State level (Communities and Local Government, Conservative, on the one hand; and Energy and Climate Change, Liberal Democrat, on the other hand). New planning legislation gives local residential communities the power to oppose onshore windfarm developments. Further, the UK is not on track to meet her EU-derived or self-stated (but now relaxed or timeline extended) targets. Case study material comes from the UK (Chapter 10 by Sims and Dent), the USA (Chapter 11 by Hoen), as well as Australia and New Zealand (Chapter 12 by Bond). The concluding chapter is by Dent and Sims. Practitioners and also students of valuation and surveying should find this up to date and full of usefulness.

Landfill site selection using integrated fuzzy logic and analytic network process (F-ANP)

Locating a suitable place to dispose the municipal solid wastes hygienically (sanitary landfill) is one of the fundamental subjects relating the environmental stability of cities and, in general, the human settlements. This final stage of solid waste management requires observance of a series of principles and criteria mainly including environmental, social, economical, and general acceptance criteria. The set of these criteria along with their sub-criteria causes some complexities in decision making for landfill site selection. Considering effective parameters and criteria, we developed an integrated fuzzy logic and analytic network process (i.e. F-ANP) to locate a suitable location for landfilling municipal solid wastes generated in Kahak Town, Qom, Iran. Our findings revealed that integration of fuzzy logic and ANP can give better idea compared with other models like AHP, fuzzy logic, and ANP (individually). Therefore, this model can be applied in site selection for landfill of other similar places.

Photocatalytic treatment of municipal wastewater using modified neodymium doped TiO2 hybrid nanoparticles.

Photocatalytic degradation of municipal wastewater was investigated using reagent grade TiO2 and modified neodymium doped TiO2 hybrid nanoparticles. For the first time, surface modification of Nd3 + doped TiO2 hybrid nanoparticles were carried out with n-butylamine as surface modifier under mild hydrothermal conditions. The modified nanoparticles obtained were characterized by Powder XRD, FTIR, DLS, TEM, BET surface area, zeta potential and UV-Vis Spectroscopy. The characterization results indicated better morphology, particle size distribution and low agglomeration of the nanoparticles synthesized. It was found that photodegradation of wastewater using surface modified neodymium doped TiO2 nanoparticles was more compared to pure TiO2, which can be attributed to the doping and modification with n-butylamine.

Elimination of arsenic contamination from water using chemically modified wheat straw

Abstract Presence of arsenic in natural water resource as a common contaminant has always been a great concern for the scientists. The objective of this study was to explore the possibility of wheat straw modified with sodium bicarbonate (NaHCO3) for removing arsenate from aqueous solution. Adsorption process was accomplished in a laboratory-scale batch with emphasis on the effect of various parameters such as pH, contact time, arsenic concentration, and adsorbent dosage on the adsorption efficiency. In order to understand the adsorption process, sorption kinetics and equilibrium isotherms were also determined. It was found that adsorption of the arsenic is influenced by several parameters such as arsenic initial concentration, adsorbent dosage, and solution pH. Maximum adsorption efficiency was achieved at a pH of 7. The equilibrium adsorbed amount also increased with the initial concentration of the metal ions, as expected. NaHCO3 was used to modify wheat straw and scanning electron microscopy images sh...

Photocatalytic degradation of Amaranth and Brilliant Blue FCF dyes using in situ modified tungsten doped TiO2 hybrid nanoparticles

This study focuses on the process of photocatalytic degradation of popular dyes like Amaranth and Brilliant Blue, using reagent grade TiO2 and in situ modified tungsten doped TiO2 hybrid nanoparticles. One of the drawbacks of nanoparticles is their agglomeration and poor dispersion in the medium as well as their limited activity in the ultra violet region, which makes them less efficient. In order to overcome such drawbacks, for the first time, in situ surface modification and doping of TiO2 nanoparticles were carried out employing n-butylamine as surface modifier and tungsten oxide as dopant. Modification was conducted under mild hydrothermal conditions (T = 150 °C, P = autogenous). Nanoparticles obtained were characterized using Powder XRD, FTIR, DLS, Zeta potential, UV-Vis spectroscopy, and TEM. The characterization indicated the desired results with respect to morphology, particle size distribution and less agglomeration. The results of the process of photodegradation of Brilliant Blue FCF and Amaranth dyes showed a higher efficiency for in situ modified tungsten doped TiO2 hybrid nanoparticles than for reagent grade TiO2.

Solar degradation of Direct Blue 71 using surface modified iron doped ZnO hybrid nanomaterials

This paper reports photodegradation of Direct Blue 71 under irradiation by sunlight. We synthesized Fe:ZnO nanomaterials under mild hydrothermal conditions (P = autogenous, T = 100 °C, t = 18 h). The precursors were Fe(2)O(3) as dopant, n-butylamine as surface modifier, NaOH as mineralizer and reagent grade ZnO. The systematic experiments on the photodegradation of Direct Blue 71 were carried out by changing different effective parameters. The variables in this study were type of nanomaterials synthesized (4 types), nanomaterial dosage (0.4-1.0 g/L), contact time (30-120 min), pH (3-11), and dye concentration (20-100 ppm). The photodegradation efficiency was determined using a UV-Vis spectrophotometer. Determination of total organic carbon (TOC) amount was used to find out mineralization efficiency. Our experimental results revealed that the nanomaterials synthesized had higher efficiency compared with the reagent grade ZnO. The best efficiency was achieved at the following conditions: 1.0 g/L nanomaterials loading, 120 min contact time, pH 5, and photodegradation efficiency from more than 75 up to 99% depending upon the dye concentration.

In situ surface modification of molybdenum‐doped organic–inorganic hybrid TiO2 nanoparticles under hydrothermal conditions and treatment of pharmaceutical effluent

Molybdenum‐doped TiO2 organic–inorganic hybrid nanoparticles were synthesized under mild hydrothermal conditions by in situ surface modification using n‐butylamine. This was carried out at 150°C at autogeneous pressure over 18 h. n‐Butylamine was selected as a surfactant since it produced nanoparticles of the desired size and shape. The products were characterized using powder X‐ray diffraction, Fourier transform infrared spectrometry, dynamic light‐scattering spectroscopy, UV–Vis spectroscopy and transmission electron microscopy. Chemical oxygen demand was estimated in order to determine the photodegradation efficiency of the molybdenum‐doped TiO2 hybrid nanoparticles in the treatment of pharmaceutical effluents. It was found that molybdenum‐doped TiO2 hybrid nanoparticles showed higher photocatalytic efficiency than untreated TiO2 nanoparticles.

Photocatalytic degradation of Aniline from aqueous solutions under sunlight illumination using immobilized Cr:ZnO nanoparticles

The present study aimed at synthesizing chromium doped zinc oxide nanoparticles (Cr:ZnO NPs) under mild hydrothermal conditions (temperature ~100 °C, p = autogenous and time ~12 hr). Chromium oxide and n-butylamine were used as dopant and surface modifier, respectively. The characteristics of the synthesized nanoparticles were determined through conducting specialized experiments including powder XRD, FTIR, SEM, EDX, and UV-VIS spectroscopy. Then, the Cr:ZnO NPs were immobilized on a sandblasted glass through thermal method. The photocatalytic degradation of aniline was conducted in a continuous reactor with a volume of 1.5 liters. Before and after photocatalytic degradation, the immobilized Cr:ZnO NPs were characterized for SEM and EDX to determine the degree of stability of immobilized nanoparticles as well as the influence of the current applied on them. The photodegradation operational parameters investigated were aniline initial concentration (150, 200, and 250 mg/L), pH (5, 7, 6, and 12), and reaction time (2, 4, and 6 hours) under sunlight illumination. The characterization results indicated high purity of the Cr:ZnO NPs and no change in morphology or composition even after the immobilization and photo-oxidation process. Finally, it was found that the optimum conditions for 93% removal of aniline under sunlight illumination was about 6 hours retention time at pH 9.

Application of micellar enhanced ultrafiltration (MEUF) for arsenic (v) removal from aqueous solutions and process optimization

ABSTRACT In this study, the removal of arsenic was evaluated using micellar-enhanced ultrafiltration process. Response surface methodology and Box-Behnken matrix methods were also applied to design the experiments and determine the optimum conditions. Therefore, the main operational parameters including pH (4–10), initial concentration of arsenic (20–80 µg/L), and concentration of Cetyltrimethylammonium bromide (CTAB) (1–3 mM) were investigated. The results of analysis of variance revealed a good agreement between experimental data and the built model with the determination coefficient (R2) of 0.99. Accordingly, the removal efficiency obtained was about 94.8% at the optimal condition (pH = 6.73, the initial concentration of arsenic = 29.44 µg/L, and CTAB concentration of 2.83 mM). GRAPHICAL ABSTRACT