This paper summarizes some of the results from a sixteen-months WERF Emerging Technology project that started January 2002. The research used rheology to arrive at a standard protocol to measure residuals network's strength in terms of energy dissipated in a given volume of a suspension. Another objective of this research is to correlate the network strength to the conditioning and dewaterability and study the factors affecting the network strength. Highlights form this project include:

A mathematical model for determining biosolids floc or “network” strength using both torque and concentric rheometers has been developed;

The reproducibility of the rheological measurements at the lab scale level was established;

The correlation between the network strength and optimum polymer dose at the lab-scale level, where a “dip” in the network strength indicates the optimum polymer dose, was established;

The “dip” in the network strength from full-scale centrifugation and gravity belt thickening of two different biosolids and residuals was also established; and

The major factors affecting the network strength (e.g., mixing conditions, rotational speed, polymer type) were studied.

This paper addresses both the mathematical model for determining the network strength using rotational rheometers and the preliminary results showing the correlation between the network strength and the optimum polymer dose at the laboratory scale level only. UR - http://www.ingentaconnect.com/content/wef/wefproc/2003/00002003/00000012/art00003 M3 - doi:10.2175/193864703784755201 UR - http://dx.doi.org/10.2175/193864703784755201 ER -