Dry-Weather Deposition and Flushing for Combined Sewer Overflow Pollution Control

摘要

This report summarizes the results of a two year study aimed at addressing the feasibility cost effectiveness and ease of application of upstream solids control as an integral part of overall combined sewer management. In the first phase four test segments on different streets in the Boston sewerage system were field flushed over an extended period to quantify the effectiveness of flushing deposition accumulation from a single pipe segment. The second phase was concerned with the problem of flushing a long flat stretch of combined sewer laterals. Flushes were injected into the uppermost manhole and pollutant levels in the flush wave passing three downstream manholes were monitored, providing insights into flushing effectiveness over three segments of pipe. Settleability tests were also performed for the purpose of estimating how far beyond the flushing monitoring manholes would the materials be carried. In the third phase, an automatic sewer flushing module was designed, fabricated, installed and operated on a single segment for an extended period. The purpose of this work was to begin to develop operational experience, using automated flushing equipment.