No abstract

This project has studied the appropriateness of the ABR for on-site primary sanitation in low-income communities. The baffled design of the ABR ensures high solids retention resulting in high treatment rates, while the overall sludge production is characteristically low. Effluent COD values measured from a 3 000 l pilot ABR using domestic wastewater at a wastewater treatment works were consistently below 200 mgCOD/l at an HRT of 22 h, and a 1 log reduction of pathogen indicator organisms (E. coli and total coliforms) was observed. Analysis of results indicates that the operating flow rate was too high to allow complete fermentation of particulate COD; it is expected that better COD and pathogen removal will be obtained at smaller hydraulic/organic loads. This paper presents results obtained for a 5 month analytical period at a single operating point. Operational and institutional issues relating to the appropriateness of the technology for on-site sanitation are explored, as well as the acceptability of the technology to target communities. Health related aspects associated with reuse of the effluent for agricultural purposes are discussed.

A novel DNA purification technology is described that enables the purification of pure dsDNA from blood. When compared to existing DNA purification methods, the Whatman BioScience Purification System (WBPS) offers a fast and convenient way to recover high yields of DNA. WBPS is based on a unique filter system that entraps DNA within a matrix. This allows the process to be performed in a single unidirectional reaction vessel, reducing user interaction and multiple centrifugation steps.

This WRC funded project has studied the appropriateness of the ABR (anaerobic baffled reactor) for on-site primary sanitation in low-income communities. A 3,000 L pilot reactor was located at the Kingsburgh wastewater treatment plant south of Durban, South Africa. Feed to the reactor was raw domestic wastewater containing a significant proportion of particulate organic matter. The compartments of the ABR were routinely monitored for pH, COD, and gas production, among other physical-chemical determinants. The microbial population in each compartment was analysed by fluorescent in situ hybridisation, using general oligonucleotide probes for eubacteria and archeae and a suite of 10 genera or family specific probes. Scanning electron microscopy was conducted on the sludge fraction of each compartment. Mixed fractions from each compartment were also analysed for health-related indicator bacteria (total coliforms and E. coli). Results indicated that methanogenesis was not occurring to the expected extent in the latter compartments, and that this was probably due to a hydraulic load limitation. This contrasted with earlier studies on industrial effluent, for which the organic load was exclusively in soluble form. Inactivation of health-related indicator bacteria was less than 1 log, indicating the need for an additional post-treatment of the effluent to protect community health.