1.1 Introduction

1.2 40 CFR Part 503 regulation

1.2.1 General provisions

1.2.2 Land application General requirements Pollutant limits Pathogen reduction Vector attraction reduction Management practices Monitoring

Record keeping Reporting

1.2.3 Surface disposal General requirements Pollutant limits Management practices

Pathogen and vector attraction reduction requirements


Record keeping


Surface disposal of domestic septage

Placement of sludge in a municipal solid waste landfill

1.2.4 Pathogen and vector attraction reduction Pathogen reduction alternatives

Class A pathogen requirements Class B pathogen requirements Vector attraction reduction options

1.2.5 Incineration Pollutant limits Management practices Frequency of monitoring Record keeping and reporting

Wastewater Sludge Processing, By Izrail S. Turovskiy and P. K. Mathai Copyright © 2006 John Wiley & Sons, Inc.


Water is the most useful and important resource of life—life depends on it. When wastewater is treated to return this resource to the environment, a semisolid, nutrient-rich by-product called wastewater sludge is produced. It typically contains 0.25 to 7% solids by weight. When processed properly, the resulting product, known as biosolids, has several beneficial uses, including (1) applying to cropland to improve soil quality and productivity because of the nutrients and organic matter it contains, (2) using as a soil amendment in landscaping, and (3) using as a daily cover or part of a final landfill cover.

The U.S. Environmental Protection Agency (EPA) and the Water Environment Federation (WEF) promote the use of the term biosolids to emphasize the beneficial use of wastewater sludge solids. However, in this book the term biosolids is used only to refer to sludge that has been processed for beneficial use, and the term sludge is used exclusively before beneficial use criteria have been achieved and in conjunction with a process descriptor, such as primary sludge, secondary sludge, return activated sludge, and waste activated sludge. The term solids is also used both before and after the beneficial use criteria have been met. Note that screenings and grit are also waste-water solids but are not sludge solids.

Approximately 6.3 million metric tons (6.9 million U.S. tons) (dry solid weight) of municipal wastewater sludge was produced in the United States in 1998 (U.S. EPA, 1999). This is projected to increase to 6.9 million and 7.4 million metric dry tons (7.6 million and 8.2 million U.S. dry tons) in the years 2005 and 2010, respectively. Figure 1.1 shows the estimates of biosolids use and disposal in 1998.

The quantity of sludge produced in a wastewater treatment plant is approximately 1% of the quantity of treated wastewater. While treatment of waste-water takes several hours, processing of the sludge generated and preparing it for disposal or beneficial use takes several days or even several weeks and necessitates the use of more complex equipment. That is why sludge management costs 40 to 50% of the total wastewater treatment costs. Therefore, the processing, reuse, and disposal of wastewater sludge must be managed by municipalities in a cost-effective way and at the same time taking into account prevailing local, state, and federal regulations. The purpose of this book is to describe the prevailing methods for the planning, design, and implementation of wastewater sludge management programs. A discussion of the U.S. EPA's 40 CFR Part 503 regulations, Standards for the Use or Disposal of Sewage Sludge, is given in the rest of this chapter.


Under the authorities of the Clean Water Act as amended, the U.S. EPA promulgated in 1993 at 40 Code of Federal Regulation (CFR) Part 503, Stan-

Combined Beneficial Use 4.1 MDT (60%)



Other Disposal 0.1 MDT (l%)

Land Applicationa 2.8 MDT (41%)

Advanced Treatment 0.8 MDT (12%)

Other Disposal 0.1 MDT (l%)

Land Applicationa 2.8 MDT (41%)

Surface Disposal/Landfill 102 MDT (17%)


Other Beneficial Use 0.5 MDT (7%)

Surface Disposal/Landfill 102 MDT (17%)


MDT (1988) = millions of dry tons aWithout further processing or stabilization such as composting

Figure 1.1 Estimates of biosolids use and disposal.

dards for the Use or Disposal of Sewage Sludge. The intent of this regulation is to ensure that sewage sludge is used or disposed of in a way that protects both human health and the environment. The regulation is divided into five subparts: (1) general provisions, (2) land application, (3) surface disposal, (4) pathogens and vector attraction reduction, and (5) incineration. The subparts are described in the following sections.

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