Empirical modelling and dual-performance optimisation of a hydrogen sulphide removal process for biogas treatment.

This study was conducted in order to investigate the use of a simple, low-cost technology for the removal of hydrogen sulphide (H(2)S) from biogas, consisting of an anoxic biotrickling filter. Modelling and optimisation of the process was achieved by studying two independent variables (H(2)S concentration and biogas flowrate) and two simultaneous performance criteria (H(2)S removal efficiency (%) and H(2)S loading rate (g/(m(3) bed day)), which were inversely related. The experiments were carried out on a bioreactor with a 12 L packing volume.

Dynamics of selected pre-existing polybrominated diphenylethers (PBDEs) in municipal wastewater sludge under anaerobic conditions.

Despite the rapid, widespread accumulation of polybrominated diphenylethers (PBDEs) in our surroundings, their environmental fate has been largely unknown. In the present study, most common congeners (BDE 47, 99, 100, 138, 153, 154, 183 and 209) were investigated for their dynamics in municipal sewage sludge under mesophilic condition (37 degrees C). In anaerobic batch cultures, the concentrations of BDE 47, 99, 100 and 209, exhibited significant decreases (by 22-40% from their initial concentration), whereas the levels of the other congeners, BDE 138, 153, 154 and 183, remained stable during a 238-d incubation.

Evaluation of different packing media for anoxic H2S control in biogas.

This paper presents the experimental results obtained during the operation of two biotrickling filters packed with 6.7 L of commercially available plastic fibres and lava rocks, respectively. The biotrickling filters were tested under similar operating conditions for hydrogen sulphide (H2S) removal from biogas under anoxic conditions, in order to determine the influence of biogas flow rate and H2S concentration on the process performance and to facilitate process modelling.

Development and application of an oligonucleotide microarray and real-time quantitative PCR for detection of wastewater bacterial pathogens.

Conventional microbial water quality test methods are well known for their technical limitations, such as lack of direct pathogen detection capacity and low throughput capability. The microarray assay has recently emerged as a promising alternative for environmental pathogen monitoring. In this study, bacterial pathogens were detected in municipal wastewater using a microarray equipped with short oligonucleotide probes targeting 16S rRNA sequences.

Microwave-assisted extraction (MAE) for the determination of polybrominated diphenylethers (PBDEs) in sewage sludge.

An efficient microwave-assisted extraction (MAE) method has been developed and evaluated for the quantification of eight major polybrominated diphenylethers (PBDEs) in sewage sludge. The PBDEs were extracted from wet and dry sludge in a microwave extraction unit using a hexane/acetone mixture for 35 min at a controlled temperature of 130 degrees C. The extract was concentrated, cleaned up on a silica gel column, and analyzed by gas chromatography/mass spectrometry (GC/MS) in the negative chemical ionization (NCI) mode.