Abstract: The present invention pertains to a molecular biology-based method and kit for measuring the specific growth rate (or cell doubling time) of distinct microbial populations. The method and kit can be used to analyze mixed culture samples that have been exposed to chloramphenicol or other protein synthesis inhibitors for defined times. In a preferred embodiment, the method of the invention (also referred to herein as FISH-RiboSyn) is an in situ method that utilizes fluorescence in situ hybridization (FISH) with probes that target: (1) the 5? or 3? end of precursor 16S rRNA; or (2) the interior region of both precursor 16S rRNA and mature 16S rRNA. Images can be captured for a defined exposure time and the average fluorescent intensity for individual cells can be determined. The rate of increase of the whole cell fluorescent intensity is used to determine the specific growth rate.

Abstract: An anaerobic digestion process for the treatment of domestic wastewater sludge that requires less space and funding to construct. Sludge to be treated is combined with recycled anaerobic digester sludge to form a blended sludge. The recycled anaerobic digester sludge provides a source of microorganisms necessary to initiate the breakdown of organic matter in the sludge to be treated. The sludge is then concentrated to increase total solids content to about 10-20%. Excess liquid is removed from the concentrated sludge. The concentrated sludge is then digested in an anaerobic reactor system such as a plug-flow reactor. Some benefits of the system's reduced volume, as a result of concentration of the sludge, include elimination of the necessity of substantially continuous stirring and the new possibilities for the types of construction to be used for the reactor. In addition to the reduced cost of the process itself, the process creates biogas that can be used to offset energy requirements for the process.