Production and characterization of graphene oxide-engineered biochars and application for organic micro-pollutant adsorption from aqueous solutions.

In this study, conventional and Graphene Oxide-engineered biochars were produced and thoroughly characterized, in order to investigate their potential as adsorptive materials. Two types of biomass, Rice Husks (RH) and Sewage Sludge (SS), two Graphene Oxide (GO) doses, 0.1% and 1%, and two pyrolysis temperatures, 400 °C and 600 °C were investigated.

Effect of biochar produced from sewage sludge on tomato (Solanum lycopersicum L.) growth, soil chemical properties and heavy metal concentrations.

The addition of biochar, as shown in the literature, improves significantly the chemical and physical soil properties and plant growth. This study examined the effect of biochar, compost and the combination of them on growth, nutrient and heavy metal concentrations of tomato. Biochar (BC) was produced from sewage sludge by pyrolysis at the temperature of 300 °C.

Agronomic potential of biochar prepared from brewery byproducts.

This work investigated the effect of biochar produced from brewery byproducts, spent grain and surplus yeast on the physicochemical characteristics of a calcareous loam soil and plant growth of maize (Zea mays L.). Maize is a plant which needs high nitrogen fertilization, while the effect of acidic or neutral biochars on alkaline calcareous soils has only been assessed in a few studies.

Adsorption of selected organic micro-pollutants on sewage sludge biochar.

In this study, biochar was produced from three differently treated sewage sludge biomasses, in three pyrolytic temperatures, 300 °C, 500 °C and 700 °C, under continuous N supply. The produced samples were physicochemically characterized and their initial metal concentration, along with metal leaching potential, were investigated. Moreover, the application of the biochar samples as adsorbents for the removal of seven emerging organic micro-pollutants from table water and treated wastewater matrices was investigated.

The impact of biochars prepared from agricultural residues on phosphorus release and availability in two fertile soils.

Biochars have a high variability in chemical composition, which is influenced by pyrolysis conditions and type of biomass. Essential macronutrient P retained in biochar could be released and made available to plants, enhancing plant growth. This study was conducted in order to evaluate whether biochar, produced from agricultural residues, could release P in water, as well as study its potential effect on plant growth and P uptake.

Ca and Fe modified biochars as adsorbents of arsenic and chromium in aqueous solutions.

This work investigated the production of Ca and Fe modified biochars in order to use them for the removal of arsenic As(V) and chromium Cr(VI) from aqueous solutions. Rice husk was impregnated with CaO at an impregnation ratio 0.114, while both rice husk and the organic fraction of municipal solid wastes were impregnated with Fe(0) and Fe(3+) at impregnation ratios 0.

Effluent organic matter (EfOM) characterization by simultaneous measurement of proteins and humic matter.

This work developed a method, based on the Lowry method and Frølund modification, for the simultaneous determination of proteins and humic matter in wastewater effluent samples at low concentrations. The method was based on simultaneous spectrophotometric measurements of proteins and humic matter at 750 nm in the absence and presence of CuSO4, which is responsible for increasing the absorbance only in the presence of to proteins. Statistical analysis through ANOVA showed that the response surface of the method fit the experimental measurements at significance level lower than 0.

Coupling digestion in a pilot-scale UASB reactor and electrochemical oxidation over BDD anode to treat diluted cheese whey.

The efficiency of the anaerobic treatment of cheese whey (CW) at mesophilic conditions was investigated. In addition, the applicability of electrochemical oxidation as an advanced post-treatment for the complete removal of chemical oxygen demand (COD) from the anaerobically treated cheese whey was evaluated. The diluted cheese whey, having a pH of 6.

Sequential treatment of diluted olive pomace leachate by digestion in a pilot scale UASB reactor and BDD electrochemical oxidation.

The efficiency of the anaerobic treatment of olive pomace leachate (OPL) at mesophilic conditions was investigated. Daily and cumulative biogas production was measured during the operational period. The maximum biogas flowrate was 65 L/d, of which 50% was methane.

Arsenic and chromium removal from water using biochars derived from rice husk, organic solid wastes and sewage sludge.

Biochars derived from rice husk, the organic fraction of municipal solid wastes and sewage sludge, as well as a sandy loam soil, were used as adsorbents for As(V), Cr(III) and Cr(VI) removal from aqueous solutions. The kinetic study showed that sorption can be well described by the pseudo-second order kinetic model, while simulation of sorption isotherms gave better fit for the Freundlich model. The materials examined removed more than 95% of the initial Cr(III).

Detection and fate of antibiotic resistant bacteria in wastewater treatment plants: a review.

Antibiotics are among the most successful group of pharmaceuticals used for human and veterinary therapy. However, large amounts of antibiotics are released into municipal wastewater due to incomplete metabolism in humans or due to disposal of unused antibiotics, which finally find their ways into different natural environmental compartments. The emergence and rapid spread of antibiotic resistant bacteria (ARB) has led to an increasing concern about the potential environmental and public health risks.

Inactivation of Bacillus anthracis in water by photocatalytic, photolytic and sonochemical treatment.

Bacillus anthracis is one of the most dangerous and pathogenic bacterial species and its intrusion in aquatic environments is a serious threat to public health. The aim of the present study was to investigate inactivation rates of B. anthracis in water by means of photocatalytic (UVA/TiO2), photolytic (UVC) and sonochemical treatment.

Treatment of municipal landfill leachate by catalytic wet air oxidation: Assessment of the role of operating parameters by factorial design.

The wet air oxidation (WAO) of municipal landfill leachate catalyzed by cupric ions and promoted by hydrogen peroxide was investigated. The effect of operating conditions such as WAO treatment time (15-30min), temperature (160-200°C), Cu(2+) concentration (250-750mgL(-1)) and H(2)O(2) concentration (0-1500mgL(-1)) on chemical oxygen demand (COD) removal was investigated by factorial design considering a two-stage, sequential process comprising the heating-up of the reactor and the actual WAO. The leachate, at an initial COD of 4920mgL(-1), was acidified to pH 3 leading to 31% COD decrease presumably due to the coagulation/precipitation of colloidal and other organic matter.

Boron-doped diamond anodic treatment of landfill leachate: evaluation of operating variables and formation of oxidation by-products.

Landfill leachate with a low BOD/COD ratio was electrochemically oxidized by means of a boron-doped diamond anode. In addition to organic matter removal, this study addressed the issue of formation of both chlorinated organic compounds and nitrate ions as a result of organic matter and ammonia and/or organic nitrogen electro-oxidation in the presence of chloride ions. A factorial design methodology was implemented to evaluate the statistically important operating variables: treatment time (1-4 h), pH (5-8), current intensity (6.

Pilot treatment of olive pomace leachate by vertical-flow constructed wetland and electrochemical oxidation: an efficient hybrid process.

A hybrid process comprising biological degradation in a vertical-flow constructed wetland (CW) and electrochemical oxidation over boron-doped diamond electrodes to decolorize, mineralize and detoxify a leachate from olive pomace processing (OPL) was investigated. Two alternative treatment schemes were compared: According to the first treatment scheme, OPL was treated by electrochemical oxidation followed by treatment in a constructed wetland pilot unit (CW-A). The second scheme comprised of treatment in a constructed wetland followed by electrochemical treatment (CW-B).

A comparative treatment of stabilized landfill leachate: coagulation and activated carbon adsorption vs. electrochemical oxidation.

This work investigated the treatment of a landfill leachate that had previously undergone biological treatment. Two treatment schemes were compared: the first one involved coagulation followed by activated carbon adsorption, whilst the second was electrochemical treatment. Coagulation with alum resulted in a 50% removal of chemical oxygen demand (COD).

Treatment of ink effluents from flexographic printing by lime precipitation and boron-doped diamond (BDD) electrochemical oxidation.

Effluent treatment from flexographic printing was investigated by precipitation/coagulation and electrochemical oxidation over boron-doped diamond electrodes. Precipitation with 3 g/L of lime led to complete removal of effluent turbidity (initial value of about 410 NTU) but only about 20% chemical oxygen demand (COD) decrease (initial value of about 1,900 mg/L). Higher lime dosages (up to 15 g/L) had no effect on separation.

Analysis of selected pharmaceutical compounds and endocrine disruptors in municipal wastewater using solid-phase microextraction and gas chromatography.

The aim of this work was to develop a simple analytical method to determine the presence of selected pharmaceutical compounds, personal care products, and endocrine disruptors in wastewater treatment plant effluents. In this study, solid-phase microextraction (SPME) and gas chromatography with mass spectroscopy (GC-MS) were used to identify triclosan; 2,4-dichloro phenol; 2,3,4-trichloro phenol; galaxolide; tonalide; estrone; 17-beta-estradiol; 17-alpha-ethinyl estradiol; clofibric acid; and carbamazepine. Extraction parameters such as types of SPME fiber, effect of ionic strength, magnetic stirring, pH, extraction temperature, extraction time, and desorption time were investigated to optimize the SPME-GC method.

Boron-doped diamond anodic treatment of olive mill wastewaters: statistical analysis, kinetic modeling and biodegradability.

The electrochemical treatment of olive mill wastewaters (OMW) over boron-doped diamond (BDD) electrodes was investigated. A factorial design methodology was implemented to evaluate the statistically important operating parameters, amongst initial COD load (1000-5000 mg/L), treatment time (1-4h), current intensity (10-20A), initial pH (4-6) and the use of 500 mg/L H(2)O(2) as an additional oxidant, on treatment efficiency; the latter was assessed in terms of COD, phenols, aromatics and color removal. Of the five parameters tested, the first two had a considerable effect on COD removal.

Simultaneous photocatalytic oxidation of As(III) and humic acid in aqueous TiO2 suspensions.

The simultaneous photocatalytic oxidation of As(III) and humic acid (HA) in aqueous Degussa P25 TiO(2) suspensions was investigated. Preliminary photocatalytic studies of the binary As(III)/TiO(2) and HA/TiO(2) systems showed that As(III) was oxidized more rapidly than HA and the extent of photocatalytic oxidation of each individual component (i.e.

Advanced treatment of the reverse osmosis concentrate produced during reclamation of municipal wastewater.

The work investigated the treatment of the concentrate produced from the reverse osmosis treatment of an MBR effluent. Two conventional chemical processes, coagulation and activated carbon adsorption, and three advanced oxidation processes (electrochemical treatment, photocatalysis and sonolysis) were applied. Coagulation with alum gave dissolved organic carbon (DOC) removals up to 42%, while FeCl(3) achieved higher removals (52%) at lower molar doses.

Wet air oxidation of table olive processing wastewater: determination of key operating parameters by factorial design.

The wet air oxidation of an effluent from edible olive processing was investigated. Semibatch experiments were conducted with 0.3L of effluent loaded into an autoclave and pure oxygen fed continuously to maintain an oxygen partial pressure of 2.

Complete treatment of olive pomace leachate by coagulation, activated-carbon adsorption and electrochemical oxidation.

A battery scheme comprising sequential alum coagulation, activated-carbon adsorption and electrochemical oxidation over boron-doped diamond electrodes to mineralize a leachate from olive pomace processing is demonstrated. The effect of coagulant and adsorbent concentration on treatment efficiency was assessed in the range 0.1-50 mM Al(3+) and 2.

Production of activated carbon from bagasse and rice husk by a single-stage chemical activation method at low retention times.

The production of activated carbon from bagasse and rice husk by a single-stage chemical activation method in short retention times (30-60min) was examined in this study. The raw materials were subjected to a chemical pretreatment and were fed to the reactor in the form of a paste (75% moisture). Chemicals examined were ZnCl2, NaOH and H3PO4, for temperatures of 600, 700 and 800 degrees C.

Electrochemical oxidation of table olive processing wastewater over boron-doped diamond electrodes: treatment optimization by factorial design.

The electrochemical treatment of an effluent from edible olive processing over boron-doped diamond electrodes was investigated. The effect of operating conditions, such as initial organic loading (from 1340 to 5370 mg/L chemical oxygen demand (COD)), reaction time (from 30 to 120 min), current intensity (from 5 to 14 A), initial pH (from 3 to 7) and the use of 500 mg/L H2O2 as an additional oxidant, on treatment efficiency was assessed implementing a factorial experimental design. Of the five parameters tested, the first three had a considerable effect on COD and total phenols removal, while the other two were statistically insignificant.