7.0 Introduction

Biosolids (or sludge) disposal has always represented a substantial portion of the costs associated with municipal wastewater treatment. Over the past 25 years, legal restrictions placed on biosolids/sludge disposal practices (e.g., ban on ocean dumping) together with public opposition to certain types of biosolids disposal practices (e.g., incineration) have encouraged many public wastewater treatment utilities to regard biosolids beneficial use as an increasingly cost-effective biosolids management alternative.

Beneficial use of biosolids generally is defined as the application of biosolids to land in order to take advantage of their nutritional and/or soil-conditioning characteristics [4,22,49]. Throughout the world, public health and environmental concerns regarding biosolids management practices are accelerating biosolids beneficial use as an acceptable alternative to landfilling or incineration. For example, in the United States, the ocean dumping ban of 1988, together with the increasing costs of landfilling and incineration, has prompted many communities to invest in biosolids beneficial use (note that in 1996, approximately 36 percent of biosolids were being used beneficially in the United States). In Europe, the decision by the European Economic Community (EEC) to eliminate ocean dumping of biosolids by 1998 has led to a substantial increase in the number of biosolids management programs with a focus on beneficial use, whereas in Japan, where over 80 percent of biosolids currently are either incinerated or landfilled, it is anticipated that over 3 million metric tons per year of biosolids will be used beneficially by the year 2015 [4,5,33].

Although most countries have their own national...