EVALUATION OF ENVIRONMENTAL AND HEALTH IMPACTS OF LAND APPLICATION OF BIOSOLIDS

Turning waste materials into usable commodities has been a subject of active research in the fields of waste management and sustainability. Presence of beneficial chemical elements and compounds in the dominantly-organic sewage sludge and their potential use as a soil nutrient is one of the main reasons for finding potentially beneficial use of the ever-increasing quantity of sewage sludge, generated from wastewater treatment plants. Numerous studies have been conducted on the use of treated sewage sludge—called biosolids—in agricultural applications. Both laboratory- and field-scale studies have been carried out by a number of investigators to assess the environmental and health impacts of biosolids. But the results have not been unanimous, particularly when viewed in context of the question: "whether or not biosolids are beneficial or harmful to human and animal health?” While many studies show that land application of biosolids is safe from the perspective of human and animal health, other studies indicate that it is harmful. In order to provide an objective evaluation of the controversy, a systematic review of scientific literature was conducted with the intent of offering a fact-based evidence to decision makers on environmental and health effects of the use of biosolids for soil enrichment and restoration. Accordingly, a Google Scholar search, using the phrase “environmental and health effects of land application of sewage sludge/biosolids,” was conducted that retrieved over 300 journal articles for the period 1999-2014. Using the basic criterion of whether or not the published study addressed the above question, the list was narrowed down to 86 articles that specifically dealt with the beneficial or harmful effects. Each of these articles was comprehensively reviewed and grouped into one of the three categories: (a) supporting the claim that biosolids pose significant harm to human and animal health, (b) affirming the claim that they do not produce significant harm, and (c) inconclusive: not supporting either side of the controversy but indicating caution in the use of biosolids. The presentation discusses the current status of knowledge on the use of biosolids for soil amendment, the methodology used, and the result of literature evaluation.