THE DETERMINATION OF SETTLED SLUDGE VOLUME AND SLUDGE VOLUME INDEX USING PROCESS METHODOLOGIES

摘要

One of the key analytical parameters used to assess the performance of typical municipal wastewater processes is the determination of the settled sludge volume (SV) within the aeration basin. Commonly, this measurement method is performed on a bench scale using a settlometer. This method is sensitive to sampling technique, agitation methods, variations in suspension, process temperature, dimensions of the settling column, and the amount of time between sampling and the start of the determination; all of which can significantly affect results~1. The test is time-consuming and because of this it is typically performed only once per day. rnTo help eliminate the difficulty in performing the SV measurement, an on-line instrument has been designed to continuously perform the measurement on-site. The methodology includes purging the previous sample, accepting a new sample, and performing the measurement. The instrument design includes a uniquely shaped settlometer vessel. This specially designed vessel increases the settling rate and reduces the analysis time. This decreased time has been correlated to the standardized laboratory methods for the 30-minute SV standard protocol across a wide number of samples. Thus, shortened cycle time for the process SV measurement is the result.rnTwo on-line SV instruments were installed in the aeration basins of two different municipal wastewater plants. These installations provided data that can be compared directly to the utilities’ laboratory values generated from their treatment process. These installations sites also provided the opportunity to calculate Sludge Volume Index (SVI) when the total suspended solids (TSS) measurements from the aeration basin are measured concurrently.