Laboratory pilot scale study for H2S removal from biogas in an anoxic biotrickling filter.

The purpose of this laboratory pilot scale study at the Wastewater Technology Centre (WTC), Environment Canada, Burlington, ON was to investigate the anaerobic biological removal of H2S from biogas under real-time operating conditions. Biogas produced in a 538 litre pilot anaerobic digester was continuously fed into a 12 litre biotrickling filter containing plastic fibres as packing bed media. The process was monitored for several months. The biogas flowrate and H2S concentration ranged between 10 to 70 L/h and 1,000 to 4,000 ppmv respectively over the course of the test period. Nitrate-rich wastewater from a pilot scale sequencing batch reactor effluent was used as the nutritive solution for the biotrickling filter. The paper presents the influence of several operational parameters such as biogas flowrate, hydrogen sulphide concentration and composition of nutrient solution on process performance. To date, our results show H2S removal rates up to 100% without adverse effects on the methane concentration of the biogas. No system deterioration was observed over long term operation. This non-conventional technology is very promising and could be considered for full scale applications.

Psychopathology in pathological gamblers seeking treatment.

High rates of psychiatric symptoms have been reported in pathological gamblers. This study of psychiatric comorbidity in pathological gamblers is the first to use structured psychiatric interviews assessing DSM-III-R Axis I and II disorders. The Structured Clinical Interview for DSM III-R (SCID-P, SCID-II) was administered to 40 (25 male, 15 male) pathological gamblers seeking outpatient treatment in Minnesota for gambling, and 64 (41 male, 23 female) controls. High lifetime rates of Axis I (92%) but not Axis II (25%) psychopathology were found in pathological gamblers as compared to controls. No differences between male and female gamblers were found in rates of affective, substance use or personality disorders. Females had higher rates of anxiety disorders and histories of physical/sexual abuse. Possible associations between psychiatric disorders and pathological gambling are discussed along with gambler typologies and implications for future research.