Biotransformation of micropollutants in moving bed biofilm reactors under heterotrophic and autotrophic conditions.

We investigated the transformation of four pharmaceuticals (Diclofenac, Naproxen, Ibuprofen and Carbamazepine) in a moving bed biofilm reactor subjected to different COD/N ratios in four experimental phases. The shift from medium to high range COD/N ratio (i.e.

Biodegradation of organophosphorus pesticides in moving bed biofilm reactors: Analysis of microbial community and biodegradation pathways.

We investigated the performance of a lab-scale moving bed biofilm reactor (MBBR) with respect to general bioconversion processes and biotransformation of two commonly used organophosphorus pesticides, Chlorpyrifos (CHL) and Malathion (MAL). The reactor was operated for 300 days under different organic loads by changing hydraulic retention time (HRT). The decrease in organic load resulted in the formation of a thinner biofilm and the growth of more biomass in the bulk, which greatly shifted bioconversion processes.

Synergy of combined free nitrous acid and Fenton technology in enhancing anaerobic digestion of actual sewage waste activated sludge.

In this study, actual swage waste activated sludge in batch reactors was employed to assess the synergistic effect of free nitrous acid and Fenton pre-treatments on enhancing methane production in the anaerobic digestion process. In addition to methane enhancement, the mechanisms driving the enhancement were also investigated via measuring enzymes activity and solubilisation of organic matter. This study revealed that the combined pre-treatments solubilised organic matter significantly more than the bioreactors pre-treated with individual FNA and Fenton.

Fe O @GO on silica sand as an efficient and economical adsorbent; Typical application for removal of phenol and 2,4-dichlorophenol from water samples.

In this research, the layer-by-layer coating of silica sand surface with monolayer of graphene oxide (GO) immobilized on magnetite nanoparticles (Fe O MNPs) sublayer was investigated as a novel, low-cost, effective, and green nanocomposite material for adsorption of phenol and 2,4-dichloro-phenol (DCP). Several characterization techniques such as FTIR spectroscopy, X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM) were used to confirm the successful synthesis of Fe O MNPs@GO on silica. The efficiency of Fe O MNPs@GO-coated silica (SiO ) for the removal of the target phenolic compounds from water samples was evaluated.

An integrated methodology for establishing industrial effluent limits in developing countries: Iran as a case study.

Background: Environmental policies should be developed in a contextual decision-making process regarding local environmental concerns emphasizing the economic, technical, social and institutional considerations. Establishing emission limit levels, especially in the industrial sector, is one of the most problematic environmental issues in developing countries, for which it is essential to include several criteria that reflect their country-specific constraints and capacities. Since Best Available Technology (BAT) is acknowledged to be the reference element for sustainable development and a basis for Emissions Limit Values (ELVs), the objective of this study is to present a reliable methodology for establishing ELVs thresholds with an emphasis on the BAT concept for national regulation at the sector level.

Stabilizing of poly(amidoamine) dendrimer on the surface of sand for the removal of nonylphenol from water: Batch and column studies.

In this work, a novel adsorbent with stabilizing of PAMAM dendrimer on the surface of sand was successfully synthesized and used to remove NP from water. The characterization of the adsorbent was performed by XRD, FTIR, TEM, and FE-SEM. Batch and column studies were conducted to evaluate the performance of the adsorbent.

Improvement of anaerobic digestion of sewage mixed sludge using free nitrous acid and Fenton pre-treatment.

Background: Recently, it has been indicated that free nitrous acid (FNA) and Fenton pre-treatment of waste activated sludge can enhance methane production in anaerobic digestion of waste activated sludge. In addition, it has been revealed that the substances used in these pre-treatments are both eco-friendly and economically attractive because not only are they produced in anaerobic digestion, but they are also low priced. Since primary sludge and waste activated sludge are mixed prior to anaerobic digestion in the majority of wastewater treatment plants, this study aims to assess the influence of combined FNA and Fenton on the anaerobic digestion of mixed sludge.

Improving biogas production from continuous co-digestion of oily wastewater and waste-activated sludge by hydrodynamic cavitation pre-treatment.

Hydrodynamic cavitation (HC) was evaluated as a pretreatment for synthetic oily wastewater (OWW) to be co-digested with waste-activated sludge (WAS). The main objective of the present research was the enhancement of biogas production by the application of HC pretreatment. HC was applied to the OWW, and the OWW and WAS were added to a 50 L continuous digestion reactor.

Hydrodynamic cavitation as a novel approach for pretreatment of oily wastewater for anaerobic co-digestion with waste activated sludge.

Application of hydrodynamic cavitation (HC) was investigated with the objective of biogas production enhancement from co-digestion of oily wastewater (OWW) and waste activated sludge (WAS). Initially, the effect of HC on the OWW was evaluated in terms of energy consumption and turbidity increase. Then, several mixtures of OWW (with and without HC pretreatment) and WAS with the same concentration of total volatile solid were prepared as a substrate for co-digestion.

A new flat sheet membrane bioreactor hybrid system for advanced treatment of effluent, reverse osmosis pretreatment and fouling mitigation.

This paper introduces a new hybrid electro membrane bioreactor (HEMBR) for reverse osmosis (RO) pretreatment and advanced treatment of effluent by simultaneously integrating electrical coagulation (EC) with a membrane bioreactor (MBR) and its performance was compared with conventional MBR. Experimental results and their statistical analysis showed removal efficiency for suspended solids (SS) of almost 100% for both reactors. HEMBR removal of chemical oxygen demand (COD) improved by 4% and membrane fouling was alleviated according to transmembrane pressure (TMP).

Evaluation of membrane bioreactor for advanced treatment of industrial wastewater and reverse osmosis pretreatment.

The evaluation of a membrane bioreactor (MBR) for pretreatment of reverse osmosis (RO) in order to reuse and reclamation of industrial town wastewater treatment plant was investigated in this study. Performance of MBR effluent through water quality in term of parameters such as chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN) and total coliform (TC) were measured. Also Silt density index (SDI) was used as indicator for RO feed water.

Comparison of COD removal from pharmaceutical wastewater by electrocoagulation, photoelectrocoagulation, peroxi-electrocoagulation and peroxi-photoelectrocoagulation processes.

This work makes a comparison between electrocoagulation (EC), photoelectrocoagulation, peroxi-electrocoagulation and peroxi-photoelectrocoagulation processes to investigate the removal of chemical oxygen demand (COD) from pharmaceutical wastewater. The effects of operational parameters such as initial pH, current density, applied voltage, amount of hydrogen peroxide and electrolysis time on COD removal efficiency were investigated and the optimum operating range for each of these operating variables was experimentally determined. In electrocoagulation process, the optimum values of pH and voltage were determined to be 7 and 40 V, respectively.

Optimizing aeration rates for minimizing membrane fouling and its effect on sludge characteristics in a moving bed membrane bioreactor.

In MBR processes, sufficient aeration is necessary to maintain sustainable flux and to retard membrane fouling. Membrane permeability, sludge characteristics, nutrient removal and biomass growth at various air flow rates in the membrane and moving bed biofilm reactor (MBBR) compartments were studied in a pilot plant. The highest nitrogen and phosphorous removal rates were found at MBBR aeration rates of 151 and 85 L h(-1) and a specific aeration demand per membrane area (SAD(m)) of 1.

Comparative cancer risk assessment of THMs in drinking water from well water sources and surface water sources.

This research evaluates the lifetime cancer risks from trihalomethanes in Tehran's drinking water. The Trihalomethanes were measured in seven different water districts. Sixty-three samples were taken from tap water across the city for 7 months.

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.

Fluoride removal from industrial wastewater using electrocoagulation and its adsorption kinetics.

Electrocoagulation (EC) process using aluminum electrodes is proposed for removing fluoride from treated industrial wastewater originated from steel industry. Effects of different operating conditions such as temperature, pH, voltage, hydraulic retention time (HRT) and number of aluminum plates between anode and cathode plates on removal efficiency are investigated. Experimental results showed that by increasing HRT, removal efficiency increases but after 5 min changes are negligible.