Comparison of treatability of four different chlorophenol-containing wastewater by pyrite-Fenton process combined with aerobic biodegradation: Role of sludge acclimation.

Aerobic biodegradation combined with pyrite-Fenton process was used for the treatment of wastewater containing different chlorophenols (4-CP, 2,3-DCP, 2,4-DCP, 2,4,6-TCP). Fenton degradation using pyrite as the low cost iron catalyst was used as a pre-treatment step to lower the toxicity of CPs prior to aerobic biodegradation. Synthetic wastewater spiked directly with either 100 mg/L CPs or pyrite-Fenton pre-treated CPs was fed to the batch bioreactors inoculated with unacclimated or acclimated activated sludge using glucose as the C-source.

Ligand enhanced pharmaceutical wastewater treatment with Fenton process using pyrite as the catalyst: Column experiments.

Advanced oxidation processes offer practical and cost effective solutions for the treatment of poorly biodegradable industrial wastewaters. Here, column experiments were performed to understand the role of a complexing agent, citrate, on Fenton-treatment of an actual pharmaceutical wastewater with pyrite as the catalyst under dynamic flow conditions. Our results suggest that the pharmaceutical wastewater treatment with Fenton reaction using pyrite as the catalyst was mainly regulated by the extent of Fe dissolution from pyrite, which, in turn, resulted in formation of hydroxyl radicals in solution.

Simultaneous hydrogen production and pollutant removal from olive mill wastewaters using electrohydrolysis process.

Management of olive mill wastewaters is one of the most challenging environmental issue in Mediterranean countries due to its high organic load, color, presence of phenolic compounds and need for high energy cost. Performance of electrohydrolysis (EH) process in terms of removal of organic compounds, detoxification and discoloration of olive mill wastewater (OMW) with simultaneous energy production in the hydrogen gas form has been investigated using aluminum electrodes. Different reaction times and electric potential gradients have been tested in order to determine the most effective conditions for removal of pollutants.

Hydrogen production from municipal wastewaters via electrohydrolysis process.

Nowadays, studies investigating alternative treatment processes for domestic wastewater have gained momentum. Rather than using conventional treatment plants which require energy and high amount of chemicals in order to treat the wastewaters, it is a viable option to use effective methods and to get clean energy in the form of hydrogen with alternative methods. Therefore, the aim of this study is to investigate the effect of electrohydrolysis process on domestic wastewater treatability at different DC voltages (4, 6, 8 and 10 V).

Role of complexing agents on oxidative degradation of chlorophenolic compounds by pyrite-Fenton process: Batch and column experiments.

This study involves batch reactor and fixed-bed continuous flow experiments to determine the effects of complexing agents (e.g., tartrate and citrate) on the treatment of chlorophenolic (CP) compounds using heterogeneous Fenton system with pyrite mineral as the iron source.

Oxidative degradation of chlorophenolic compounds with pyrite-Fenton process.

Batch experiments, in conjunction with chromatographic and spectroscopic measurements, were performed to comparatively investigate the degradation of various chlorophenolic (CP) compounds (e.g., 2-CP, 4-CP, 2,3-DCP, 2,4-DCP, 2,4,6-TCP, 2,3,4,6-TeCP) by a modified Fenton process using pyrite as the catalyst.

Volatile fatty acid production dynamics during the acidification of pretreated olive mill wastewater.

This study focuses on the dynamics of VFA production from pretreated olive mill wastewater (OMW). Acidogenic anaerobic sequencing batch reactors (AcASBR) were operated with the pretreated OMW at hydraulic retention time (HRT) of 2days and pH of 5,5 for different organic loading rates (OLRs) ranging from 5gCOD/L.d to 40gCOD/L.

Ultrasound pretreatment for enhanced biogas production from olive mill wastewater.

This study investigates applicability of low frequency ultrasound technology to olive mill wastewaters (OMWs) as a pretreatment step prior to anaerobic batch reactors to improve biogas production and methane yield. OMWs originating from three phase processes are characterized with high organic content and complex nature. The treatment of the wastewater is problematic and alternative treatment options should be investigated.

Ultrasound assisted biogas production from landfill leachate.

The aim of this study is to increase biogas production and methane yield from landfill leachate in anaerobic batch reactors by using low frequency ultrasound as a pretreatment step. In the first part of the study, optimum conditions for solubilization of organic matter in leachate samples were investigated using various sonication durations at an ultrasound frequency of 20 kHz. The level of organic matter solubilization during ultrasonic pretreatment experiments was determined by calculating the ratio of soluble chemical oxygen demand (sCOD) to total chemical oxygen demand (tCOD).

Inhibition effect of isopropanol on acetyl-CoA synthetase expression level of acetoclastic methanogen, Methanosaeta concilii.

Isopropanol is a widely found solvent in industrial wastewaters, which have commonly been treated using anaerobic systems. In this study, inhibitory effect of isopropanol on the key microbial group in anaerobic bioreactors, acetoclastic methanogens, was investigated. Anaerobic sludges in serum bottles were repeatedly fed with acetate and isopropanol; and quantitative real-time PCR was used for determining effect of isopropanol on the expression level of a key enzyme in acetoclastic methane production, acetyl-CoA synthetase of Methanosaeta concilii.

Identification of pseudomurein cell wall binding domains.

Methanothermobacter thermautotrophicus is a methanogenic Gram-positive microorganism with a cell wall consisting of pseudomurein. Currently, no information is available on extracellular pseudomurein biology and so far only two prophage pseudomurein autolysins, PeiW and PeiP, have been reported. In this paper we show that PeiW and PeiP contain two different N-terminal pseudomurein cell wall binding domains.

Inhibition of volatile fatty acid production in granular sludge from a UASB reactor.

Inhibition of volatile fatty acids (VFA), namely acetate, butyrate, and propionate, on the activity of acetoclastic methanogens within a full-scale upflow anaerobic sludge blanket (UASB) reactor was investigated using specific methanogenic activity (SMA) test. SMA tests were carried out at acetate concentrations in a range of 1000-25,000 mg l(-1), butyrate concentrations in a range of 3000-25,000 mg l(-1) and propionate concentrations between 500-10,000 mg l(-1). Maximum potential methane production (PMP) rates were obtained as 389 ml CH4 gTVS(-1) x d(-1) at 3000 mg l(-1) acetate concentration, 432 ml CH4 gTVS(-1) x d(-1) at butyrate concentration of 5000 mg l(-1), and 162 mlCH4 gTVS(1) x d(-1) at 1000 mg l(-1) propionate concentration.

Effect of wastewater composition on methanogenic activity in an anaerobic reactor.

In this study, effects of a chemical synthesis-based pharmaceutical wastewater on activity of acetoclastic methanogens within a lab-scale anaerobic completely stirred tank reactor (CSTR) were investigated. The CSTR was initially fed with glucose and loaded up to an organic loading rate of 6 kg COD m(-3) d(-1) at which 92% soluble COD removal efficiency was achieved. Acetoclastic methanogenic activity was found to be 336 mL CH4 gTVS(-1) d(-1).

Microbial population dynamics in an anaerobic CSTR treating a chemical synthesis-based pharmaceutical wastewater.

Effects of a chemical synthesis based pharmaceutical wastewater on performance of an anaerobic completely stirred tank reactor (CSTR), activity of acetoclastic methanogens and microbial composition were evaluated under various influent compositions. Initially, the CSTR was fed with glucose up to an organic loading rate (OLR) of 6 kg COD/m3 x d corresponding to an F/M ratio of 0.43 with a hydraulic retention time (HRT) of 2.