Fact Sheet. Land Application Of Sewage Sludge #3

FS953

Fact sheet For a comprehensive list of our publications visit www.rce.rutgers.edu

Land Application of Sewage Sludge (Biosolids)* #3: Different Types of Sewage Sludge Uta Krogmann, Extension Specialist in Solid Waste Management & Lisa S. Boyles, Program Associate in Solid Waste Management

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his fact sheet is designed to provide general information on and about the differences between sewage sludge types, and how various types of sewage sludge can be used. Various terms used in this fact sheet are explained in the glossary on page 3. This fact sheet is intended to provide information without endorsing any particular decision.

and Environmental Protection Agency (EPA) in additon to undergoing additional treatment to stabilize and disinfect it. During stabilization and disinfection, pathogens are significantly reduced (Class B) or reduced to below detection limits (Class A). For more information about pathogens refer to the Rutgers Cooperative Extension (RCE) fact sheet FS958 Land Application of Sewage Sludge(Biosolids), #8: Pathogens.

What is Sewage Sludge? Sewage sludge is a by-product of the purification of wastewater. In most cases, sewage sludge consists of the solids removed from wastewater by settling during the primary treatment and the excess bacteria which have digested the dissolved organic matter during the secondary biological treatment. This process of wastewater treatment produces 1) treated water that can be discharged back into local bodies of water; and, 2) sewage sludge. The resulting sewage sludge has significant organic matter content and contains macro- and micro-nutrients essential for plant growth. Sewage sludge can also contain contaminants such as heavy metals, organic contaminants, and pathogens. However, before it can be used for land application, sewage sludge must meet limitations for contaminants established by the New Jersey Department of Environmental Protection (NJDEP)

Types of Sewage Sludge The type of sewage sludge will depend upon the stabilization and disinfection method used. Final forms of sewage sludge that are modified for land application include: ●

liquid sewage sludge

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advanced alkaline stabilized sewage sludge

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composted sewage sludge

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pelletized sewage sludge

Different types of sewage sludge have different properties and common uses that can be found in the following table.

* The term biosolids is commonly used for sewage sludge that can be used beneficially. In this document we will use the more inclusive term sewage sludge.

Different Types of Sewage Sludge and Their Characteristics Liquid

Advanced Alkaline Stabilized

Composted

Pelletized

Properties

1-8% solids content

Relatively dry; significant liming value

Relatively stable; humus-like

Dry, flows well

Stabilization and Disinfection Method

Aerobic digestion, anaerobic digestion, or lime stabilization

Addition of lime material such as quick lime, hydrated lime, or cement kiln dust

Composting

Drying sewage sludge at high temperatures

Common Use

Nutrient source

Mostly as a liming material

Soil amendment

Specialty fertilizer mixes, sidedress fertilizer

Pathogen Reduction Standard

In most cases Class B

Class A

In most cases Class A

Class A

Meadowlife®, BioFix®, ECO LIME®

Sure Grow®, Cape Organic®, Soil Life®

Milorganite®, Ocean Gro®

Examples

Mention or display of a trademark, proprietary product, or firm in text or figures does not constitute an endorsement by Rutgers Cooperative Extension and does not imply approval to the exclusion of other suitable products or firms.

Regulations

FS951 #1: Questions to Ask Before Considering Application on Farmland FS952 #2: Regulations and Guidelines FS954 #4: Guidelines for Land Application in Agriculture FS955 #5: Heavy Metals FS956 #6: Soil Amendments and Heavy Metals FS957 #7: Organic Contaminants FS958 #8: Pathogens

Anyone interested in using sewage sludge should consult the federal and state regulations and the RCE fact sheet FS954 Land Application of Sewage Sludge (Biosolids), #4: Guidelines for Land Application in Agriculture carefully before use. For further information, refer to the RCE fact sheet FS952 Land Application of Sewage Sludge (Biosolids), #2: Regulations.

Please contact your local county Cooperative Extension office, the Rutgers Publications Distribution Office or visit the RCE, Cook College Web site, http:// www.rce.rutgers.edu/ to obtain additional information regarding the use of sewage sludge for land application.

Conclusions There are a variety of types of sewage sludge available for use. They have a range of characteristics, which makes each type useful for different purposes.

References USEPA. 1994. A Plain English Guide to the EPA Part 503 Biosolids Rule. EPA/832/R-93/003. USEPA, Office of Wastewater Management, Washington, DC.

Additional Information Other fact sheet titles in this series include:

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Glossary Advanced alkaline stabilization

Process of blending sewage sludge with a high pH material, such as kiln dust and quick lime. During the process, the material undergoes a chemical reaction that pasteurizes the product by raising the pH to greater than 12 for 72 hours or longer, while maintaining elevated temperature and air drying requirements.

Aerobic digestion

The degradation of concentrated wastewater solids, during which aerobic bacteria (bacteria which need the presence of oxygen) break down the organic matter into mostly inert solids, carbon dioxide, and water.

Anaerobic digestion

The degradation of concentrated wastewater solids, during which anaerobic bacteria (bacteria which can not live in the presence of oxygen) break down the organic matter into mostly inert solids, carbon dioxide, and methane.

Class A pathogen reduction level

Pathogens in a sewage sludge are below detectable levels (40 CFR Part 503.32(a)). For more information refer to the RCE fact sheet FS958 Land Application of Sewage Sludge (Biosolids), #8; Pathogens.

Class B pathogen reduction level

Pathogens in sewage sludge are detectable but crop and site restrictions are used to allow environmental conditions (light, heat, drying) to reduce pathogen densities until risk of disease transmission is minimal. (40 CFR Part 503.32(b)). For more information refer to the RCE fact sheet FS958 Land Application of Sewage Sludge (Biosolids), #8: Pathogens.

Lime stabilization

Process of adding a sufficient amount of lime to sewage sludge to raise the pH to 12 for 2 hours. This is done to substantially reduce the number and prevent the re-growth of pathogenic and odor-producing organisms.

Primary Treatment

The first major treatment in a wastewater treatment facility, in which heavy particles settle out.

Secondary Biological Treatment

The second step in most waste treatment systems in which bacteria digest the dissolved organic matter of the waste.

Stabilization

Treatment process that reduces pathogens and vector attraction in sewage sludge.

Vector attraction reduction

Methods that reduce the attractiveness of sewage sludge to vectors (flies, rodents) to reduce the potential for transmitting diseases.

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© 2004 by Rutgers Cooperative Research & Extension, NJAES, Rutgers, The State University of New Jersey. Desktop publishing by Rutgers-Cook College Resource Center

Published: July 1999

RUTGERS COOPERATIVE RESEARCH & EXTENSION N.J. AGRICULTURAL EXPERIMENT STATION RUTGERS, THE STATE UNIVERSITY OF NEW JERSEY NEW BRUNSWICK Distributed in cooperation with U.S. Department of Agriculture in furtherance of the Acts of Congress on May 8 and June 30, 1914. Rutgers Cooperative Extension works in agriculture, family and community health sciences, and 4-H youth development. Dr. Karyn Malinowski, Director of Extension. Rutgers Cooperative Research & Extension provides information and educational services to all people without regard to race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, or marital or family status. (Not all prohibited bases apply to all programs.) Rutgers Cooperative Research & Extension is an Equal Opportunity Program Provider and Employer.