Daniel J. Watts

Effect of sulfate on the methanogenic activity of a bacterial culture from a brewery wastewater during glucose degradation.

The maximum specific methanogenic activity (SMA) of a sludge originating from a brewery wastewater treatment plant on the degradation of glucose was investigated at various levels of sulfate on a specific loading basis. Batch experiments were conducted in serum bottles at pH 7 and 35 degrees C. A comparison of the values indicates that the SMA of this mixed culture was increased and reached its highest level of 0.128 g CH4 gas COD/(g VSS x d) when biomass was in contact with sulfate at a ratio of 1:0.114 by weight.

Optimum organic loading rate for semi-continuous operation of an anaerobic process for biogas production from Jatropha curcas seed cake

This paper reports on biogas production by anaerobic digestion of Jatropha curcas seed cake in semi continuous flow at 30°C, focusing on increasing the organic loading rate (OLR) of seed cake by investigating levels of 1.25, 1.67, 2.5, 3.33 and 5 kg Chemical Oxygen Demand (COD)/m³ day. Reactors were fed at flow rates of 125, 167, 250, 333 and 500 ml/day, yielding Hydraulic Retention Times (HRTs) of 40, 30, 20, 15 and 10 days. Increasing the OLR decreases the organic digestion. The highest methane yield (340 l at STP/kg COD degraded) was obtained at the OLR of 1.25 kg COD/m³ day.

Heavy metal resistant anaerobic bacterial strains from brewery digester sludge

This work focused on the study of the types of heavy-metal-resistant anaerobic bacteria from the sludge of a brewery wastewater treatment plant exposed to high concentrations of dissolved Cd (II), Cu (II) and Zn (II). Characterisations were carried out by polymerase chain reaction of the 16S rRNA gene of bacterial strain. Using special culture media, two types of strong heavy metal-resistant bacterial strains were isolated. The first was a sulphate-reducing bacterium identified as Clostridium ganghwense strain HY-42-06. This strain of sulphate-reducing bacteria tolerated Cd (II), Cu (II) and Zn (II) at the tested concentrations. The other type was identified as consisting of a mixture of Micrococcus luteus, Wolinella succinogenes, Sporosarscina sp. PIC-C28 and Alicycliphilus sp. R-24604. The results found that these four dominant strains tolerated Cd (II) at 20 mg/l, only Wolinella succinogenes cannot tolerate Cu (II) at 2 mg/l while none of them tolerated Zn (II) at 30 mg/l.

A conceptual framework for intelligent monitoring systems

This paper discusses the conceptual development of a continuously monitored intelligent system for underground infrastructure. The proposed sensors are based on advanced coupling and refinement of several technologies: electrically conducting composite pipe (ECCP), electrochemical impedance spectroscopy (EIS) and time domain reflectometry (TDR). A significant benefit gleaned from the combination of these technologies is that the resulting system may be used on non-metallic, as well as, metallic pipes. In addition, the synergism of the technologies obtains the maximum information regarding defect location and characterization. The monitoring signal, waveguides, and damage sensor are also discussed, as well as, the data fusion, dynamic modeling and simulation requirements for the intelligent monitoring system.