AS 4276.23:2016 pdf free
AS 4276.23:2016 pdf free.Water microbiology Method 23: Soils, sediments, sludges, slurries and bio-solids – Procedures for sample preparation
Treated organic solids produced by wastewater treatment processes that in most cases can be beneficially recycled. The term biosolids does not include untreated wastewater sludges,industrial sludges or the product produced from the high temperature incineration of sewage sludge. Biosolids are typically thickened and dewatered and include blended materials such as soil improvers, fertilizers, composts and worm castings.
NOTE: The terms‘sludge’ and“biosolid’ are often used synonymously, however biosolids are treated sludge. For the purposes of this Standard, either term may be used, with that preferred by the end-user recommended, with the exception of untreated wastewater sludges, industrial sludges and the product produced from the high temperature incineration of sewage sludge.
Solid, semi-solid and viscous liquid (i.e. high moisture content sludge) samples are mixed as much as practicable. Subsamples as necessary are quantitatively suspended in a homogenization buffer or an enrichment medium. Sample homogenization procedures are based on whether the sample is liquid or solid. The suspension is subjected to vigorous mixing to produce a uniform homogenate by any of several methods (shaking, blending,stomaching) and pH adjusted to 7.0-7.5 or the pH of the applicable growth medium. The homogenate may then be used directly as sample material for MPN-based determinations and serially-diluted for both MPN, spread-plate and membrane filtration methods. Liquid enrichment media are the starting point for both MPN and presence/absence analyses.
For reporting of results on a dry weight basis, a subsample is dried at 103°C-105°C to constant weight for gravimetric determination of percent total solids, with the result being used to calculate the MPN or cfu (colony forming units)g dry weight.
NOTES:
1 A 10-fold w/v dilution results from the solids homogenization process. Such dilution can reduce interference by matrix materials on growth media, including matrix-associated potentially toxic materials such as metals and antimicrobials. The impact of such interferences should be considered if homogenized sample is analysed directly without dilution; such as for liquid samples, or homogenates produced with a <10-fold concomitant dilution.
2 Sample must be homogenized in order to effectively adjust pH.AS 4276.23 pdf free.
