Monitoring water quality characteristics during disposal of sewage sludge at the 106-mile site

Abstract

Battelle Ocean SciencesD u b u r y , MA Regulation of sewage sludge disposal at the 106-Mi 1 e Deepwater Municipal Sludge Site is contingent upon achieving Environmental Protection Agency saltwater quality criteria (WQC) or limiting permissible concentrations (LPC) within four hours of disposal. These criteria must be met in less time if the plume is transported across the site boundary in less than four hours. sample collection from within the plume. Collecting these samples presents several difficulties, including positioning of the sampling platform within the plume, location of the maximum concentrations of the plume at depth, and collecting the samples from within this maximum. Combining in situ sensors, including CTD and transmissometry, with realtime shipboard display of data, and high-volume pumping systems has provided the necessary direction and control over sample depths to successfully sample sewage plumes for up to 8 hours following disposal. This capability allowed collection of water. samples for several parameters useful for tracing the dispersion and dilution of the sludges in addition to determining concentrations relative to marine WQC. The results from samples collected in several plumes during September 1987, indicate dumping rates currently used a t the 106-Mile Site may be affected if permits to dump at the site are issued.