Novel microbial-electrochemical filter with a computer-feedback pH control strategy for upgrading biogas into biomethane.

A novel microbial-electrochemical filter was designed and operated based on a combined microbial electrolysis cell and bio-trickling filter principles with the aim to maximize gas-liquid mass-transfer efficiency and minimize costs associated with bubbling biogas through liquid-filled reactor. CO/biogas feed to the MEF was done via a computer-feedback pH control strategy, linking CO feed directly to the OH production. As a result current efficiency was constant at around 100% throughout the period of experiments.

Proof of concept of wastewater treatment via passive aeration SND using a novel zeolite amended biofilm reactor.

The current paper describes a novel passive aeration simultaneous nitrification and denitrification (PASND) zeolite amended biofilm reactor that removes organic carbon and nitrogen from wastewater with low-energy consumption. Next to the ammonium oxidizing bacteria (AOB), this reactor contained naturally enriched glycogen accumulating organisms (GAOs) and zeolite powder to initially adsorb BOD (acetate) and ammonium (NH -N) from synthetic wastewater under anaerobic conditions. Draining of the treated wastewater exposed the biofilm directly to air enabling low-energy oxygen supply by passive aeration.

Ethanol and lactic acid production from sugar and starch wastes by anaerobic acidification.

Anaerobic conversion of carbohydrates can generate various end-products. Besides physical parameters such as pH and temperature, the types of carbohydrate being fermented influences the fermentation pattern. Under uncontrolled pH, microbial mixed cultures from activated sludge and anaerobic digester sludge anaerobically produced ethanol from glucose while producing lactic acid from starch conversion.

Anaerobic acidification of sugar-containing wastewater for biotechnological production of organic acids and ethanol.

Anaerobic acidification of sugars can produce some useful end-products such as alcohol, volatile fatty acids (e.g. acetate, propionate, and butyrate) and lactic acid.

Concurrent Lactic and Volatile Fatty Acid Analysis of Microbial Fermentation Samples by Gas Chromatography with Heat Pre-treatment.

Organic acid analysis of fermentation samples can be readily achieved by gas chromatography (GC), which detects volatile organic acids. However, lactic acid, a key fermentation acid is non-volatile and can hence not be quantified by regular GC analysis. However the addition of periodic acid to organic acid samples has been shown to enable lactic acid analysis by GC, as periodic acid oxidizes lactic acid to the volatile acetaldehyde.

Bioelectrochemical enhancement of anaerobic digestion: Comparing single- and two-chamber reactor configurations at thermophilic conditions.

Bioelectrochemical system (BES) can act as an auxiliary technology for improving organic waste treatment and biogas production in anaerobic digestion (AD). For the first time this study directly compared the performance of a single- and a cation-exchange membrane-equipped two-chamber BES-AD systems at thermophilic conditions. The results indicated that an active glucose-fed thermophilic anaerobic sludge could readily (<3days) increase biogas production in both reactor configurations by inserting a carbon electrode poised at -0.

Automatic online buffer capacity (alkalinity) measurement of wastewater using an electrochemical cell.

The use of an automatic online electrochemical cell (EC) for measuring the buffer capacity of wastewater is presented. pH titration curves of different solutions (NaHCO3, Na2HPO4, real municipal wastewater, and anaerobic digester liquid) were obtained by conventional chemical titration and compared to the online EC measurements. The results show that the pH titration curves from the EC were comparable to that of the conventional chemical titration.

Novel process of bio-chemical ammonia removal from air streams using a water reflux system and zeolite as filter media.

A novel biofilter that removes ammonia from air streams and converts it to nitrogen gas has been developed and operated continuously for 300 days. The ammonia from the incoming up-flow air stream is first absorbed into water and the carrier material, zeolite. A continuous gravity reflux of condensed water from the exit of the biofilter provides moisture for nitrifying bacteria to develop and convert dissolved ammonia (ammonium) to nitrite/nitrate.

Comparison of static, in-vessel composting of MSW with thermophilic anaerobic digestion and combinations of the two processes.

The biological stabilisation of the organic fraction of municipal solid waste (OFMSW) into a form stable enough for land application can be achieved via aerobic or anaerobic treatments. To investigate the rates of degradation (e.g.