title: Studies of sludge collected from the anaerobic digester of a meat processing company

authors: Ma, Nanxin

subjects: anaerobic digestion

abstract: Anaerobic digestion is commonly used as a wastewater treatment step where complex biological substrates are progressively degraded in the absence of oxygen to produce methane and carbon dioxide with hydrogen and volatile acids occurring as intermediate products. These intermediate products are more valuable commodities than methane so there is interest in optimizing their production and recovery from the anaerobic digestion process. In previous work, a sludge sample collected from a local meat processing company was reported to produce significant amounts of hydrogen at ambient temperatures.

In the present study, eleven sludge samples were collected from the same meat processing company and characterized in terms of their solids content, pH, as-collected gas production profiles and gas production profiles and gas production rates, when repetitively batch fed with glucose at their original pH and also at pHs successively lowered to pH 4.5. Similar studies were performed using cellulose as the substrate.

In these studies, no hydrogen was produced by the as-collected sludges, but hydrogen was produced by two of the sludges when batch fed with glucose. Detailed studies of the effect of pH on one of the sludges revealed that hydrogen was produced when the pH was lowered to between 5.2 and 5.4 and batch fed with glucose. No hydrogen was formed when the sludges were batch fed with cellulose under the conditions investigated. Acid conditions severely inhibited gas production rates when both glucose and cellulose were used as substrates. Gas production rates with cellulose substrate were systematically slower than when glucose was used as the substrate.

text: Studies of sludge collected from the anaerobic digester of a meat processing company Anaerobic digestion is commonly used as a wastewater treatment step where complex biological substrates are progressively degraded in the absence of oxygen to produce methane and carbon dioxide with hydrogen and volatile acids occurring as intermediate products. These intermediate products are more valuable commodities than methane so there is interest in optimizing their production and recovery from the anaerobic digestion process. In previous work, a sludge sample collected from a local meat processing company was reported to produce significant amounts of hydrogen at ambient temperatures.

In the present study, eleven sludge samples were collected from the same meat processing company and characterized in terms of their solids content, pH, as-collected gas production profiles and gas production profiles and gas production rates, when repetitively batch fed with glucose at their original pH and also at pHs successively lowered to pH 4.5. Similar studies were performed using cellulose as the substrate.

In these studies, no hydrogen was produced by the as-collected sludges, but hydrogen was produced by two of the sludges when batch fed with glucose. Detailed studies of the effect of pH on one of the sludges revealed that hydrogen was produced when the pH was lowered to between 5.2 and 5.4 and batch fed with glucose. No hydrogen was formed when the sludges were batch fed with cellulose under the conditions investigated. Acid conditions severely inhibited gas production rates when both glucose and cellulose were used as substrates. Gas production rates with cellulose substrate were systematically slower than when glucose was used as the substrate.

year: 2010

title: Applications of system dynamics modelling to computer music

authors: Whalley, Ian

abstract: Based on a composer's psycho-acoustic imagination or response to music, system dynamics modelling and simulation tools can be used as a scoring device to map the structural dynamic shape of interest of computer music compositions. The tools can also be used as a generator of compositional ideas reflecting thematic juxtaposition and emotional flux in musical narratives. These techniques allow the modelling of everyday narratives to provide a structural/metaphorical means of music composition based on archetypes that are shared with wider audiences. The methods are outlined using two examples.

text: Applications of system dynamics modelling to computer music Based on a composer's psycho-acoustic imagination or response to music, system dynamics modelling and simulation tools can be used as a scoring device to map the structural dynamic shape of interest of computer music compositions. The tools can also be used as a generator of compositional ideas reflecting thematic juxtaposition and emotional flux in musical narratives. These techniques allow the modelling of everyday narratives to provide a structural/metaphorical means of music composition based on archetypes that are shared with wider audiences. The methods are outlined using two examples.

year: 2000

title: Waitangi Soda Springs alum dosing – bioavailability of aluminium 2013

authors: Ling, Nicholas

abstract: Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2010 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected in September 2013 to determine the bioavailability and bioaccumulation of aluminium. Comparative analyses were undertaken on kōura and goldfish collected from Lakes Rotorua and Rotoiti. Lake Rotoehu kōura and goldfish showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium but little evidence for significant bioaccumulation in tissues.

text: Waitangi Soda Springs alum dosing – bioavailability of aluminium 2013 Continuous alum dosing of the Waitangi Soda Springs at Lake Rotoehu commenced in 2010 to reduce inflows of dissolved reactive phosphorus to Lake Rotoehu. Analyses of bioaccumulation in the tissues of kōura and goldfish from Lake Rotoehu were undertaken on animals collected in September 2013 to determine the bioavailability and bioaccumulation of aluminium. Comparative analyses were undertaken on kōura and goldfish collected from Lakes Rotorua and Rotoiti. Lake Rotoehu kōura and goldfish showed slightly elevated aluminium concentrations in the gills indicating enhanced exposure to aluminium but little evidence for significant bioaccumulation in tissues.

year: 2015