Empirical Models for Predicting the Occurrence and Concentration of Organic Chemicals in Biosolids

摘要

Tens of thousands of organic chemicals are used by consumers on a routine basis for multiple applications. Despite an increasing number of publications in this area, not enough is known about their fates during wastewater treatment and upon release into the environment. For example, hydrophobic organic compounds have been shown to persist in digested municipal sludge (biosolids), an abundant by-product of wastewater treatment. The sequestration of persistent contaminants in biosolids is of concern due to the widespread practice of land application of these materials for inexpensive disposal or for use as a soil conditioner and fertilizer. Land application of biosolids represents a potential pathway for the contamination of agricultural soils, uptake into food crops, bioaccumulation in terrestrial ecosystems and human exposure. Several thousand high production volume (HPV) chemicals are produced or imported in the U.S. each year at rates exceeding 450 000 kg (1 million pounds) per chemical. Since monitoring at wastewater treatment plants of such a large number of compounds is impractical and cost-prohibitive, modeling approaches have been proposed to estimate the likely behavior of compounds during wastewater treatment. In this literature review, we present an overview of recent empirical modeling approaches for estimating both the occurrence and concentration of hydrophobic organic compounds (HOCs) in biosolids destined for application on land.