vvEPA
United States
Environmental Protection
Agency
Office of Research and
Development
Washington DC 20460
EPA/600/9-91/047
January 1992
Proceedings of
International Workshop on
Research in Pesticide
Treatment/Disposal/
Waste Minimization
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EPA/600/9-91/047
January 1992
PROCEEDINGS OF
INTERNATIONAL WORKSHOP ON RESEARCH IN PESTICIDE
TREATMENT/DISPOSAL/WASTE MINIMIZATION
February 26-27, 1991
Edited By:
T. David Ferguson
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
Sponsored by:
U.S. Environmental Protection Agency
Office of Research and Development
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
and
Tennessee Valley Authority
National Fertilizer and Environmental Research Center
Muscle Shoals, Alabama 35660
Coordinated by:
Science Applications International Corporation
Cincinnati, Ohio 45203
U.S. Environmental Proton A2ency
Region 5, Library (P:. ; /,
77 West Jackson F:-."..:. -, l&h Hoar
Chicago, IL 60604-iojO
RISK REDUCTION ENGINEERING LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OH 45268
Printed on Recycled Paper
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DISCLAIMER
The following papers have been reviewed in accordance with the U.S.
Environmental Protection Agency's peer and administrative review policies and
approved for presentation and publication:
Tracking Small Quantities of Cancelled or Excess Pesticides
Containing Dioxins and Furans
by J. Paul E. des Rosiers
Waste Minimization for Non-Agricultural Pesticide Applicators:
EPA's Pollution Prevention Guide
by Teresa M. Harten
Pesticide Container Management in the United States
by Nancy Fitz
Pesticide Disposal in Guinea-Bissau: A Case History
by Janice Jansen
All other papers published in this Proceedings describe work that was not
funded by the U.S. Environmental Protection Agency and therefore do not
necessarily reflect the views of the Agency and no official endorsement should
be inferred.
ii
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FOREWORD
Today's rapidly developing and changing technologies and industrial
products and practices frequently carry with them the increased generation of
materials that, if improperly dealt with, can threaten both public health and
the environment. The U.S. Environmental Protection Agency is charged by
Congress with protecting the Nation's land, air, and water resources. Under a
mandate of national environmental laws, the agency strives to formulate and
implement actions leading to a compatible balance between human activities and
the ability of natural systems to support and nurture life. These laws direct
the EPA to perform research to define our environmental problems, measure the
impacts, and search for solutions.
The Risk Reduction Engineering laboratory is responsible for planning,
implementing, and managing research, development, and demonstration programs
to provide an authoritative, defensible engineering basis in support of the
policies, programs, and regulations of the EPA with respect to drinking water,
wastewater, pesticides, toxic substances, solid and hazardous wastes, and
Superfund-related activities. This publication is one of the products of that
research and provides a vital communication link between the researcher and
the user community.
The U.S. Environmental Protection Agency and the Tennessee Valley
Authority's National fertilizer and Environmental Research Center have begun
promoting cost-effective treatment techniques for pesticide disposal. In
1991, the two agencies co-sponsored a workshop on the pesticide waste
minimization, treatment, and disposal. The workshop focused on current
research in waste minimization strategies and cost-effective/disposal
techniques as they effect applicators, fertilizer/agrichemical dealers and
farmers.
These proceedings from the 1991 Workshop provide the results of projects
recently completed and current information on projects presently underway.
Those wishing additional information on these projects are urged to contact
the author. It is hoped the conclusions and recommendations reached at this
workshop will be the basis of a series of regional workshops to be held in
1992.
E. Timothy Oppelt, Director,
Risk Reduction Engineering Laboratory
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ABSTRACT
The International Workshop on Research in Pesticide Management, Disposal,
and Waste Minimization was held in Cincinnati, Ohio, February 26-27,1991. The
purpose of this workshop was to provide government officials, pesticide user
groups, pesticide producers and farm organizations practical solutions to
pesticide treatment and disposal problems. The workshop focused on how to
destroy pesticides and their residuals at low cost by the applicators and
dealers. The technical program included presentations by government researchers
and regulators, university agricultural station professors, industry experts and
individuals involved in pesticide disposal and treatment.
IV
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TABLE OF CONTENTS
Disclaimer ii
Foreword ii:L
Abstract iv
Agenda vii
List of Attendess *
Introduction xii
Papers Presented:
1. Tennessee Valley Authority National Fertilizer and
Environmental Research Center - An Overview
by Joe Gautney 1
2. Tracking Small Quantities of Cancelled or Excess
Pesticides Containing Dioxins and Furans
by J. Paul E. des Rosiers 8
3. Research and Development Needs for Agrichemical Retail
Dealership Site Assessment and Remediation
by Chris Myrick 23
4. An Evaporation/Degradation System for Pesticide
Equipment Rinse Water
by Steven E. Dwinell 28
5. Pesticide Disposal Using a Demulsification, Sorption,
Filtration and Chemical and Biological Degradation Strategy
by D.E. Mullins, R.W. Young, G.H. Hetzel, and D.F. Berry .... 32
6. Landfarming and Biostimulation for Decontaminating
Herbicide Wastes in Soil
by Kudjo Dzantor and A.S. Felsot 46
7. Removal of Pesticides From Aqueous Solutions Using
Liquid Membrane Emulsions
by Dr. Verrill M. Norwood, III 68
8. Field and Laboratory Evaluations of an Activated Charcoal
Filtration Unit
by J.H. Massey, T.L. Lavy and B.W. Skulman 85
9. Preliminary Studies of Batch Chemical Oxidation of
Wastewaters Containing Agrichemicals
by C.E. Breed and M.C. Crim 95
10. Extraction of Pesticides from Contaminated Soil Using
Supercritical Carbon Dioxide
by G.B. Hunter 100
V
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CONTENTS (continued)
Page
11. Modular Concrete Pads for Pesticide and Liquid
Fertilizer Handling, Storage and Containment
by Ronald T. Noyes Ill
12. Waste Minimization for Non-Agricultural Pesticide
Applicators: EPA's Pollution Prevention Guide
by Teresa M. Harten 136
13. Pesticide Container Management in the United States
by Nancy Fitz 144
14. Pesticide Disposal in Guinea-Bissau: A Case History
by Janice Jansen 151
15. Downstream Injection Equipment for Sprayers and
Fertilizer Spreaders
by A.W. Mclaughlin, S.A. Weeks, and 0. L. Vanderslice 157
16. Evolution of the Pesticide Container Disposal Program in Alberta
by C.G. Van Teeling and W. Inkpen 161
17. Retail Fertilizer Dealer Product Containment
by M.F. Broder 166
vi
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AGENDA
TUESDAY, FEBRUARY 26, 1991
Plenary Session
9:00 Welcome
E. Timothy Oppelt, Director
Risk Reduction Engineering Laboratory
U.S. EPA
John E. Culp, Director
Technology Introduction
National Fertilizer & Environmental Research Center
Tennessee Valley Authority
9:30 U.S. EPA, ORD, RREL - An Overview
Glenn M. Shaul
U.S. EPA
9:50 Tennessee Valley Authority, National Fertilizer and Environmental
Research Center - An Overview
Joe Gautney
Tennessee Valley Authority
10:10 Break
10:20 Tracking Small Quantities of Canceled or Excess Pesticides
Containing Dioxins and Furans
J. Paul E. des Rosiers
U.S. EPA
10:40 Agrichemical Dealer/Applicator Site Assessment and Remediation
Chris Myrick
National AgriChemical Retailers Association
11:00 Keynote Address
Robert Denny
Office of Pesticide Programs
U.S. EPA
11:30 Lunch
Caprice 1 and 4 (4th Floor)
Vll
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AGENDA (continued)
Innovative Biological Treatment of Control of Pesticides
1:30 The Evaporation/Degradation System for: Pesticide Equipment
Rlnsewater - A Practical Solution to a Pesticide Waste Management
Problem
Steven E. Dwinell
Florida Department of Environmental Regulation
2:00 Pesticide Disposal Using a Demulsification, Sorption, Filtration, and
Chemical and Biological Degradation Strategy
D.E. Mullins, R.W. Young, G.H. Hetzel, and D.F. Berry
Virginia Polytechnic Institute and State University
2:30 Break
2:45 Remediation of Herbicide Haste in Soil: Experiences with Landfarming
and Biostimulation
Alan Pel sot and Kudjo Dzantor
Illinois Natural History Survey
3:15 Open Discussion
5:00 Reception - Cash Bar
Mezzanine Level above Palm Court
WEDNESDAY, FEBRUARY 27, 1991
Innovative Physical/Chemical Treatment for Control of Pesticides
8:30 Removal of Pesticides from Aqueous Solutions Using Liquid
Membrane Emulsions
Verrill M. Norwood, III and Joe Gautney
Tennessess Valley Authority
9:00 Field and Laboratory Evaluations of an Activated Charcoal
Filtration Unit
J.H. Massey, T.L. Lavy, and B.W. Skulman
University of Arkansas
9:30 Preliminary Studies of Batch Chemical Oxidation of Wastewaters
Containing Agrichemicals
Claude E. Breed and Mike C. Crim
Tennessee Valley Authority
10:00 Break
viii
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AGENDA (continued)
10:15 Cleanup of Soil Contaminated with Pesticides Using Supercritical
Carbon Dioxide Extraction
G. Bradley Hunter
Tennessee Valley Authority
Waste Minimization Practices for Pesticide Products. Formulations
and Applications
10:45 Pesticide Containment Systems
Ronald T. Noyes
Oklahoma State University
11:05 Waste Minimization for Non-Agricultural Pesticide Applicators
Teresa M. Harten
U.S. EPA
11:25 Pesticide Container Disposal in the U.S.
Nancy Fitz
U.S. EPA
11:45 Lunch
Caprice 1 and 4 (4th Floor)
1:30 Pesticide Disposal in Guinea-Bissau: A Case History
Janice Jensen
U.S. EPA
1:50 Downstream Injection Equipment for Sprayers and Fertilizer Spreaders
Stanley Weeks
Agway Farm Research Center
2:10 Evolution of the Pesticide Container
C.G. Van Teeling and W. Inkpen
Alberta Environment
2:30 Break
2:40 Retail Fertilizer Dealer Containment
Michael F. Broder
Tennessee Valley Authority
3:00 Summary Discussion on Future Research and Technology Transfer
Chaired by Patrick Eagan
University of Wisconsin
ix
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UST OF ATTENDEES AT
INTERNATIONAL WORKSHOP ON RESEARCH IN PESTICIDE
TREATMENT/DISPOSAL/WASTE MINIMIZATION
Lea Aurelius
Environmental Quality Specialist
Texas Department of Agriculture
Pesticide Regulatory Program
P.O. Box 12847
Austin, TX 78711
David Balke
Ciba-Geigy
P.O. Box 113
Mclntosh, AL 36553
Gene Carpenter
PSES Department
University of Idaho
Moscow, ID 83843
Arthur L Coleman, Jr.
Ohio EPA
1800 Watermark Drive
P.O. Box 1049
Columbus, OH 43266-0149
Steven Dwineil
Florida Dept. of Environmental Re
2600 Blair Stone Road
Tallahassee, FL 32399-2400
Kudjo Dzantor
Associate Research Biologist
Illinois Natural History Survey
607 E. Peabody Dr.
Champaign, IL 61820
lr
Dr. Duane F. Berry
Assistant Professor
Dept. of Crop & Soy
Environmental Sciences
Virginia Polytechnic Institute &
State University
Blacksburg, VA 24061
Bill Bounds
Ciba-Geigy
P.O. Box 113
Mclntosh, AL 36553
Claude Breed
Tennessee Valley Authority
CEB 3A-M, P.O. Box 1010
Muscle Shoals, AL 35560-1010
Michael Broder
Agricultural Engineer
Tennessee Valley Authority
NFE 2E, P.O. Box 1010
Muscle Shoals, AL 35560-1010
Marvin Burchfield
Qemson University SCAES
209 Agricultural Service Center
Cherry Road
demson. SC 29634-0369
John E. Gulp
Manager, Technology Introduction
Tennessee Valley Authority
NFE 2E, P.O. Box 1010
Muscle Shoals, AL 35560-1010
Robert Denny
U.S. EPA
Office of Pesticide Programs
401 M Street, S.W.
Washington, DC 20460
Paul E. des Rosiers
Senior Staff Engineer
EPA - ORD
401 M Street. S.W.
Washington, DC 20460
Roy R. Detweiler
Chadds Ford Enterprises, Inc.
P.O. Box 349
Chadds Ford, PA 19317
Clyde J. Dial
SAIC
635 W. 7th St., Suite 403
Cincinnati, OH 45203
Dr. Patrick Eagan
University of Wisconsin
Deptartment of Engineering
Professional Development
432 N. Lake St., Room 717
Madison, Wl 53706
Lee Faulconer
Washington State Department
of Agriculture
406 General Adm. Bldg., AX^I1
Olympla, WA 98504
Dave Ferguson
U.S. EPA, RREL
26 W. Martin Luther King Drive
Cincinnati, OH 45268
Nancy Fitz
Office of Pesticide Programs
U.S. EPA
401 M Street, S.W.
Washington, DC 20460
Joe Gautney
Research Chemist
Tennessee Valley Authority
NFE 2J, P.O. Box 1010
Muscle Shoals, AL 35660-1010
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Tom Gilding
NACA
1155 15th St., N.W.
Washington, DC 20005
Janet Goodwin
U.S. EPA
Office of Water Regs & Stds.
401 M Street, S.W.
Washington, DC 20460
Margaret Groeber
SAIC
635 W. 7th St., Suite 403
Cincinnati, OH 45203
Cathleen J. Hapeman-Somich
USDA, Agr. Research Service
Room 110, Bldg. 050, BARC-West
Beltsville, MD 20705
Teresa Marten
U.S. EPA (MS 476)
26 W. Martin Luther King Dr.
Cincinnati, OH 45268
Robert Hayes
Idaho Department of Agriculture
Division of Agriculture Tech.
P.O. Box 790
Boise, ID 83701
Dan Herndon
Radian Corporation
2455 Horsepen Rd., Suite 250
Herndon, VA 22701
Brad Hunter
Research Chemist
Tennessee Valley Authority
NFE 2J, P.O. Box 1010
Muscle Shoals, AL 35660-1010
Janice Jensen
Office of Pesticide Programs
U.S. EPA
401 M Street, S.W.
Washington, DC 20460
Shripat T. KamWe
State Liaison-Pesticide
Impact Assessment
University of Nebraska
101 NRH, Environmental Programs
Lincoln, NE 68583-0818
Richard N. Koustas
Treatment of Pesticides in
Contaminated Soils
U.S. EPA, RREL
2890 Woodbridge Ave.
Edison, NJ 08837
Larry Le Juene
LA Dept. of Agriculture & Forestry
P.O. Box 3596
Baton Rouge, LA 70821-3596
David Macarus
U.S. EPA Region V (5 SPT-7)
230 S. Dearborn
Chicago, IL 60604
Joe Massey, Research Assist.
University of Arkansas
Altheimer Lab
276 Altheimer Drive
Fayetteville, AR 72703
Bill McCarthy
U.S. EPA
401 M Street, S.W.
Washington, DC 20460
William T. McClelland
N.C. Department of Agriculture
P.O. Box 27647
Raleigh, NC 27611
Dr. Donald E. Mullins
Assoc. Prof., Entomology Dept.
Virginia Polytechnic Institute &
State University
Blacksburg, VA 34061
Chris Myrick
Dir. of Legislative Reg. Affairs
National Agrichemical Retailers Assn.
1155 15th St., N.W., Ninth Floor
Washington, DC 20005
Verrill M. Norwood, Jr.
Pioneer Chlor Alkali Co.
121 Blueberry Hill Rd., N.W.
Cleveland, TN 37312
Verrill M. Norwood, III
Research Chemist
Tennessee Valley Authority
NFE 2J-M, P.O. Box 1010
Muscle Shoals, AL 35630
Ronald T. Noyes
Oklahoma State University
225 AG Hall
Stillwater, OK 74078-0469
E. Timothy Oppelt
U.S. EPA, RREL
26 W. Martin Luther King Drive
Cincinnati, OH 45268
Erdal Ozkan
Agricultural Engineering Department
Ohio State University
Columbus, OH 43210
Donald L Paulson, Jr.
Ciba-Geigy Corp.
P.O. Box 18300
Greensboro, NC 27419-8300
Tom Powers
U.S. EPA, RREL
26 W. Martin Luther King Drive
Cincinnati, OH 45268
Ghulam M. Memon
Pandalia Coatings
837 6th St.
Brackenridge, PA 15014
Loma Poff
Ontario Ministry of Environment
135 St. QairAve., W.
Toronto, Ontario M4V 1P5
XI
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Dairy! Rester, Specialist Robert Wulfhorst, Specialist
Louisiana Cooperative Ext. Service Ohio Department of Agriculture
Louisiana State University 8995 E. Main Street
Knapp Hall Reynoldsburg, OH 43068
Baton Rouge, LA 70821-3596
Dave Scott R. W. Young
Office of Indiana State Chemist Virginia Polytechnic
Department of Biochemistry Institute & State University
Purdue University 352 Litton, Reaves Hall
West Lafayette, IN 47907 Blacksburg, VA 24061
Glenn Shaul Steve Zahos
U.S. EPA, RREL Envirocyde
26 W. Martin Luther King Drive P.O. Box 7
Cincinnati, OH 45268 St. Joseph, MO 64502
Subhas Sikdar
U.S. EPA, RREL
26 W. Martin Luther King Drive
Cincinnati, OH 45268
Jack M. Sullivan
Tennessee Valley Authority
NFE, 2J-M
Musde Shoals, AL 35660
Dr. Lynne Tudor
U.S. EPA
Office of Water
401 M Street, S.W.
Washington, DC 20460
Dr. C. G. Van Teellng
Special Projects Officer
Alberta Environment Pesticide
5th ROOT, Oxbridge Place
9820-106 St.
Edmonton, Alberta T5K 2J6
Dr. Stan Weeks
Agway, Inc.
P.O. Box 4933
Syracuse, NY 13221-4933
Brian Westfall
Cincinnati Solid Waste Project
26 W. Martin Luther King Drive
Cincinnati, OH 45268
Roger Wilmoth
U.S. EPA, RREL
26 W. Martin Luther King Drive
Cincinnati, OH 45268
xii
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INTRODUCTION
An international workshop on treatment, disposal, and waste minimization
of pesticides and pesticide wastes was held in Cincinnati, Ohio on February 26-
27, 1991. The purpose of this workshop was to work with government, pesticide
user groups, pesticide producers, farm organizations and academia to define and
offer practical solutions to pesticide users' treatment and disposal problems.
The technical program included presentations by government researchers and
regulators, academia, industry experts and individuals involved in pesticide
disposal and treatment.
The workshop was sponsored by the following organizations:
U.S. Environmental Protection Agency
Office of Research and Development
Risk Reduction Engineering Laboratory
Cincinnati, Ohio 45268
and
Tennessee Valley Authority
National Fertilizer and Environmental Research Center
Muscle Shoals, Alabama 35660
The following people were on the workshop planning committee:
Glenn M. Shaul
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
T. David Ferguson
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
Edwin F. Barth
U.S. Environmental Protection Agency
Center for Environmental Research Information
Margaret M. Groeber
Science Applications International Corporation
Joe Gautney
Tennessee Valley Authority
National Fertilizer & Environmental Research Center
Aside from the technical presentations, the workshop allowed for some
discussion among the participants. Several issues/concerns were discussed by the
attendees. The two issues which cause the greatest concern were site remediation
and regulatory framework.
Xlll
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Discussions on site remediation were directed toward dealer sites. The
focus on the cleanup was both soils and groundwater contamination. The largest
problems identified with dealer site cleanup were costs and issues of how clean
is clean enough. It was noted that many dealers could go bankrupt if costs were
high. Also, very little remediation is being conducted because dealers feel that
regulators can not give them cleanup levels that will hold true in the future.
Regulatory framework is also of great concern. There was much discussion
over how to solve their problem. Suggestions included the following:
1) Prove technology then worry about the regulatory framework.
2) Regulatory framework needs to be looked at while technology is being
developed—it can and does drive costs.
3) Policy people are not listening to research people.
4) Get the key players involved - Target State Regulators since they are
closest to the problem - Get the concerns and scientific information to
the pertinent regulatory people.
Another topic of discussion was waste minimization and education. It was
agreed that many of the pollution prevention ideas would greatly decrease the
number of future poblems involving pesticides. These waste minimization
techniques were generally low cost practical solutions to managing pesticides and
pesticide wastes. It is important that these ideas become common practices by
educating appropriate users and dealers of pesticides.
xiv
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Tennessee Valley Authority,
National Fertilizer and Environmental Research Center
An Overview
by
Joe Gautney
Chemical Research Department
Muscle Shoals, Alabama 35660
ABSTRACT
The National Fertilizer and Environmental Research Center (NFERC) is a
unique part of the Tennessee Valley Authority (TVA), a government agency created
by an Act of Congress in 1933. The Center, located in Muscle Shoals, Alabama,
is a national laboratory for research, development, education and
commercialization for fertilizers and related agricultural chemicals including
their economic and environmentally safe use, renewable fuel and chemical
technologies, alternatives for solving environmental/waste problems, and
technologies which support national defense. NFERC projects in the pesticide
waste minimization/treatment/disposal areas include "Model Site Demonstrations
and Site Assessments," "Development of Waste Treatment and Site Remediation
Technologies for Fertilizer/Agrichemical Dealers," "Development of a Dealer
Information/Education Program," and "Constructed Wetlands."
BACKGROUND AND INTRODUCTION
The National Fertilizer and Environmental Research Center (NFERC) is a
unique part of the Tennessee Valley Authority (TVA), a government agency created
by an Act of Congress in 1933 as part of President Franklin D. Roosevelt's New
Deal for lifting the Nation from the Great Depression. Congress gave the new
Agency a broad mandate for development of the Tennessee Valley region along with
national responsibility for fertilizer research, development, and introduction.
The Agency was also given responsibility for supporting national defense.
The Tennessee Valley Authority is a rather unique government agency.
President Roosevelt described it as "a corporation clothed with the power of
government, but possessed of the flexibility and initiative of a private
enterprise." The Agency is headed by a three-person Board of Directors, each
appointed to a nine-year term by the President of the United States with approval
of the Congress. Organizationally (Figure 1), TVA consists of three operating
groups: Generating, Customer, and Resource. The Generating and Customer Groups
are associated primarily with TVA's power production operations. The Agency owns
and operates the largest electric utility in the United States. The Resource
Group includes the Agency's river basin operations, economic and community
development activities, budget and business operations, and the National
Fertilizer and Environmental Research Center (NFERC). Many of the organizations
in the Resource Group receive core funding from Congressional appropriations.
In contrast, TVA's power production operations are entirely self-supporting.
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NATIONAL FERTILIZER AND ENVIRONMENTAL RESEARCH CENTER (NFERC)
The National Fertilizer and Environmental Research Center is located on a
1200-acre site in Muscle Shoals, Alabama. The Center has about 450 employees
which include chemists, engineers, agronomists, soil scientists, and a highly
skilled blue-collar staff for operation of pilot and prototype research
facilities. The NFERC receives core funding from Congressional appropriations
and during the last decade has come under increased pressure to supplement these
appropriations with funds from outside contract work. The FY91 NFERC budget is
$54 million ($33 million Congressional appropriations).
Fertilizer research and development was the main thrust of NFERC activities
from its beginning until a few years ago. The Center conducted basic laboratory
research with scale-up of promising technologies in pilot- and full-scale
production facilities located at NFERC. Agronomic testing of the new fertilizer
products was conducted in parallel with development of the production technology.
Once developed, new fertilizer technologies were introduced across the Nation.
This fertilizer orientation resulted in unparalleled technical improvements.
NFERC technologies are involved in production of about 75 percent of the
fertilizers in use today, and through the years NFERC has issued licenses to 400
companies for use of patented NFERC processes.
A few years ago NFERC began a shift more toward environmental research and
development. This shift was prompted by growing public and regulatory concern
over environmental pollution, particularly that from agriculture, and driven
internally by NFERC staff and externally by NFERC's Executive Industry Review
Group (EIRG). As a result of these internal and external forces, in January 1990
the Center was reorganized and its name changed from the National Fertilizer
Development Center to NFERC. The mission of NFERC is to serve as a national
laboratory for research, development, education, and commercialization for:
Fertilizers and Related Agricultural Chemicals Including Their
Economic and Environmentally Safe Use
Renewable Fuel And Chemical Technologies
Alternatives for Solving Environmental/Waste Problems
Technologies Which Support National Defense
The NFERC (Figure 2) is headed by Senior Vice President, John T. Shields.
The Center has three divisions: Research, Development, and Technology
Introduction. The Research division consists of Biotechnical, Chemical, and
Agricultural Research departments. These departments conduct basic and applied
research in their respective speciality areas. The Development division consists
of Prototype Operations, Chemical Development and Project Management departments.
The Prototype Operations Department maintains and operates NFERC's prototype
facilities for testing and demonstrating new fertilizer and environmental
technologies; the Chemical Development Department conducts bench- and pilot-scale
research and development; and the Project Management Department is responsible
for capital projects such as demolition of old full-scale production facilities,
construction of new prototype facilities, and contractual projects which NFERC
conducts for the U.S. Department of Defense. The Technology Introduction
division consists of Field Programs, Marketing, and Engineering Services
departments. The Field Programs Department works with industry and universities
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through its field engineering staff and national network of area directors to
introduce and test NFERC technologies and products. The Marketing Department is
responsible for marketing NFERC technologies and products. The Engineering
Services Department provides engineering design services to other NFERC
organizations and outside clients. It also houses the NFERC environmental staff
which is responsible for ensuring that NFERC projects and project activities meet
environmental and regulatory requirements.
NFERC Pro.lects in Pesticide Waste Minimization/Treatment/Disposal
NFERC currently has a number of projects in the pesticide waste
minimization/treatment/disposal areas. Most of these projects are being pursued
using interdisciplinary project teams which span division and department lines.
The projects are "Model Site Demonstrations and Site Assessments," "Development
of Waste Treatment and Site Remediation Technologies for Fertilizer/Agrichemical
Dealers," "Development of a Dealer Information/Education Program," and
"Constructed Wetlands."
Model Site Demonstrations and Site Assessments--
NFERC is establishing model demonstrations at fertilizer/agrichemical
dealer sites across the United States to demonstrate secondary containment
systems and other "best management practices" (BMPs) for minimizing
fertilizer/pesticide losses to the environment. Selection of sites is made by a
group composed of state fertilizer and agrichemical trade associations,
individual dealers, TVA regional directors, and field programs staff. Under the
program, NFERC provides—at no charge—technical assistance in planning and
designing the containment system and recommends other BMPs based on existing and
anticipated rules and regulations for that particular state. The participating
dealer pays all construction costs associated with bringing the site into
compliance and agrees to open his or her facility to visits by other dealers,
regulators, and other interested parties. The NFERC plans to establish twenty
model demonstration sites in fourteen states. Four sites have been completed.
NFERC also conducts site assessments on a fee basis for
fertilizer/agrichemical dealers across the United States. Under this program
NFERC environmental staff will conduct a "friendly" assessment of a dealer site
and make written recommendations for secondary containment and other BMPs. NFERC
also provides the dealer with information on applicable regulations, and
depending on the fee, will provide either generic or customized drawings for
secondary containment facilities, rinse pads, etc. To date NFERC has conducted
approximately thirty environmental site assessments for dealers. The charge for
a standard site assessment is $3,500.
Development of Waste Treatment and Site Remediation Technologies for Fertilizer/
Agrichemical Dealers--
The objectives of this project are to develop, introduce, and market waste
treatment and site remediation technologies for fertilizer/agrichemical dealers.
The project consists of four phases: Phase I - Define Problems, Phase II -
Identify "Current State of the Art" for Waste Treatment and Site Remediation
Technologies, Phase III - Evaluate/Modify/Research/Develop Waste Treatment and
Site Remediation Technologies, and Phase IV - Introduce and Market Waste
Treatment and Site Remediation Technologies.
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In Phase I information to guide the project was collected from Federal and
state regulatory agencies, nonregulatory agencies, universities, dealer and trade
associations, and basic producer organizations. During Phase II which was
conducted concurrently with Phase I, extensive literature reviews were conducted
to identify waste treatment and site remediation technologies which are
potentially applicable to waste treatment and remediation problems at
fertilizer/agrichemical dealer sites. The information from Phases I and II was
published in internal and external reports (TVA Circular Z-288) and in a series
of three TVA bulletins (Y-213 - Y-215).
The project is currently in Phase III. In this phase research is being
conducted on a number of promising waste treatment and site remediation
technologies ranging from low to high technology. These projects are:
Supercritical Fluid Extraction of Pesticides From Soils
Bioremediation of Pesticide Contaminated Soils
Batch Oxidation of Pesticides in Rinsates
Best Management Practices Bioremediation of Pesticide
Contaminated Soils
Development/Validation of Immunoassays for Pesticide Analysis
Solar Evaporation/Concentration/Degradation of Pesticides in
Rinsate Wastes
Effects of Best Management Practices on "Natural" Remediation
Soil Washing To Remove Pesticides From Soils
Supercritical Water Oxidation of Pesticide Wastes
Remediation of Pesticide-Contaminated Soils by Application to
Cropland
Promising technologies from Phase III will be demonstrated, introduced, and
marketed in Phase IV. Many of the technologies developed in Phase III will
likely be applicable (with modification) to the problems of other industries
besides fertilizer/agrichemical dealers.
Development of a Dealer Information/Education Program--
The objectives of this project are to provide fertilizer/agrichemical
dealers with information/education necessary to operate environmentally sound and
profitable businesses. A dealer environmental checklist was recently developed
in cooperation with the National Fertilizer Solutions Association and the
National AgriChemical Retailers Association. More than 15,000 of these
checklists have been distributed to dealers across the country. Other activities
under this project include development of an environmental handbook, a video
questionnaire for environmental self-assessment, and environmental workshops for
dealers; and compilation of information on state-sponsored pesticide/household
waste amnesty.days (contract work for EPA). In addition, research is being
conducted to evaluate different concretes and concrete additives, coatings, and
liner materials for construction of load pads and other containment structures.
-------
Constructed Wetlands--
The objective of this project is to develop a low-cost, low-technology
solution to the treatment of contaminated waste waters from the agribusiness
industry. Potential users of this technology include fertilizer/agrichemical
dealers and food processors.
Constructed wetlands are generally rock filled, shallow cells which util ize
plants and biological colonies that grow around their root system to absorb
and/or destroy the contaminants in the waste water. A constructed wetlands
research and development facility is scheduled for completion at NFERC in the
Spring of 1991. The facility includes a greenhouse for conducting small-scale
test work, 32 treatment test cells, and 2 larger nursery cells for propagating
plants. Data from the greenhouse work and test cells will be used to install
several demonstration test cells throughout the United States. These sites will
be selected to demonstrate a variety of waste water compositions, flow patterns,
plants, and climatic conditions.
Other NFERC Research Activities
Other NFERC research activities include production of ethanol and other
chemicals from the cellulosic portion of municipal solid wastes, utilization of
industrial and agricultural wastes in fertilizer production, development of
controlled availability fertilizer materials, and development of improved fluid
fertilizers.
Future Goals
NFERC plans to become a leader in environmental research and development--
it will continue to develop and introduce improved fertilizer technologies for
the nation—develop and demonstrate technologies for converting cellulosic wastes
to ethanol and other useful chemicals; remove old full-scale fertilizer
production facilities and clean up the plant sites; design and operate prototype
facilities for demonstrating fertilizer and environmental technologies; and
upgrade staff to meet new job demands through training, affirmative actions, and
hiring of new employees. In addition, NFERC will intensify its efforts to
increase funding from npnappropriated sources by conducting contractual work for
national defense agencies, other government agencies, and private firms.
-------
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Effective. January 8. 1991
Figure 1. Tennessee Valley Authority
-------
NATIONAL reHTE.IZIR 1 ENVIRONMENTAL RESEARCH CINTIR
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J»nu«ry S, 1*11
-------
Tracking Small Quantities of Canceled or Excess
Pesticides Containing Dioxins and Furans
by
J. Paul E. des Rosiers
U.S. Environmental Protection Agency
Office of Research and Development (RD-681)
Washington, DC 20460
ABSTRACT
Confusion currently exists regarding the treatment of suspended, canceled
or excess, registered pesticides and their respective formulations under FIFRA,
RCRA or CERCLA, particularly if soil and debris are contaminated by these
chemicals.
The paper describes what options exist for pesticide-contaminated soil and
debris or excess, registered pesticides, given that the former wastes are subject
to the RCRA land disposal restrictions and must meet prescribed treatment
standards and the latter formulations may be amenable to some creative
interpretations of RCRA small quantity generator rules or may qualify under FIFRA
for reuse and recycle by application as a pesticide according to label rates on
label-approved crops or cropland.
Storage and Disposal Plans — Final Disposition
Confusion may exist regarding the treatment of suspended and/or canceled
pesticides (e.g., endrin, heptachlor, chlordane, 2,4,5-T, 2,4,5-TP (Silvex),
lindane, DDT, etc.) under FIFRA, RCRA or CERCLA particularly if soil and debris
are contaminated by excess registered or suspended/canceled pesticides.
After the applicable effective dates, restricted waste may be land disposed
only if it meets the prescribed RCRA treatment standards, or if it has been shown
to a reasonable degree of certainty, that there will be no migration of hazardous
constituents from the disposal unit for as long as the waste remains hazardous.
At present, a treatment standard is based on the performance of the best
demonstrated available technology (BOAT) (51 FR 40578). Compliance with
performance standards may be ascertained by determining the concentration
level(s) of the principal organic hazardous constituent(s) (POHCs) in the waste,
in the treatment residual, or in the extract of the waste or treatment residual.
The Agency has identified U, P (pesticide) and F waste for which proposed
concentration-based standards have been changed to technology-based standards
(e.g., incineration). (See Tables 1-3.)
Furthermore, soil and debris that are contaminated with prohibited waste
are subject to the land disposal restrictions (LDRs) and must meet the treatment
standard, as previously described, for the contaminating waste prior to land
disposal. The Agency realizes, however, that there are certain sampling and
analytical difficulties associated with regulating hazardous waste in soil and
debris matrices. Because of such problems, the Agency is preparing a separate
rule-making that will establish treatability groups and treatment standards for
contaminated soil and debris. (See Table 4 and 5.)
-------
If the pesticide contaminated soil and debris cannot be treated to meet the
promulgated treatment standards, alternative treatment standards can be
established under a site-specific variance from the treatment standards (see 53
FR 31221, August 27, 1988) or a full-scale variance (40 CFR 268.44). In order
to be granted a site-specific variance from the treatment standard, the
petitioner must demonstrate to the Agency that because the physical (or chemical)
properties of the waste differ significantly from the waste analyzed and used to
develop the treatment standard, the waste cannot be treated to specified levels
(see 40 CFR 268.44).
Moreover, the Agency has established guidance levels for granting soil and
debris treatability variance based on limited soil and debris treatment data and
these can be found in Superfund LDR Guides #6A and 6B, July 1989 (U.S. EPA, 1989a
and U.S. EPA 1989b).
Conceptual Approach under FIFRA
The soil that contains the pesticides should be viewed as a "new inert
diluent" and, as such, comprises a carrier for the active ingredient(s) within
the pesticide formulation. Representative soil samples should be analyzed by
acceptable EPA methods to determine the concentration(s) of pesticide(s) of
regulatory concern. This target pesticide (and others) should be used to
calculate what an appropriate FIFRA-approved label rate would be for that
particular pesticide. Once this rate is determined, the pesticide-soil may then
be applied or redistributed at or below its "label rate" or agronomic rate for
the type of crop grown on the receiving field in order to take advantage, during
the active growing season or summer months, of natural or enhanced ultraviolet
(UV) photolysis and controlled biodegradation by natural or special
microorganisms. This approach is legal under RCRA because it represents recycle
and reuse of a product; the approach should also be legal under FIFRA because the
target pesticide(s) (those of most significance within the soil) is being applied
according to label rates on label-approved crops.
The success of this approach will vary from location to location, based on
specific active ingredient(s), concentration(s), and other factors, and this
process should maintain the contaminated soil within the framework of FIFRA
regulations and guidelines. If, however, RCRA becomes controlling, one option
is to utilize the approach being used under CERCLA, i.e., obtaining a soil and
debris treatability variance for remedial or removal actions (Superfund LDR
Guides #6A and 6B). (See also Table 6.)
-------
Excess Pesticides, Rinsates and Other Pesticides Containing Materials (FIFRA Part
165.62 proposed under Subpart D)
165.62 Allowable Practices and Procedures
(a) Application as a pesticide (primary method of disposition)
(1) Pesticide in the material must be known; total amount of
pesticide applied to the labeled site does not exceed the
total amount allowed on the
label; and other directions and conditions on the label are
compiled with.
(2) Any specific instructions on the label for application of
excess pesticides, rinsates, another materials are compiled
with. For excess formulation or mixture of formulation and
diluent, application as a pesticide to a labeled site at or
below the rate of application allowed on the label is clearly
within the provisions of the act.
(b) Use as diluent--Pesticide-contaminated rinsates can be used as
diluents for subsequent mixtures or the same pesticides. Rule-of-
thumb--no more than 5-10% of the volume of a mixture can be composed
of rinse water containing pesticide residues.
(c) Recycle or recovery—Excess pesticides, rinse water containing
pesticides and other pesticide containing materials can be offered
for recycling or recovery under proposed regulation; but EPA Office
of Pesticide Programs (OPP) definitions of each option differ from
normally accepted definitions. For example, recycling involves
returning of the pesticide to the manufacturer of the active
ingredient for extraction of same; whereas, recovery is limited to
combustion for energy value.
(d) Storage as a pesticide—If excess pesticide, rinse waters, or other
pesticide containing materials cannot be immediately applied as a
pesticide, such as a diluent, or recycled and recovered, the
material may be stored as a pesticide until it can be employed in
one of those manners. However, it must be stored in compliance with
applicable pesticide storage regulations (at the present time, the
regulations do not specify a time limit for storage of these
materials as pesticides.) The applicability limit set by FIFRA
Subpart B is 11,000 pounds (5.5 tons or approximately 20 drums) and
60 days. The limit is also triggered by 1,350 gallons of rinsates.
(e) Waste materials—If the excess pesticide, rinse waters, or other
pesticide containing material cannot be used as stated previously,
then these materials must be handled as wastes under RCRA, that is,
if they cannot be handled in accordance with 40 CFR 165.62 (a)-(d)
or if they contain any solvent other than the diluent specified on
the label.
10
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Practical Example and Potential Remedy
Waste containing chlorophenols are particularly difficult to address under
RCRA and has often perplexed many during and after the implementation of the
removal or remedial action phases (Collison, 1990). Not only are the current
RCRA rules confusing, but EPA has added to the discomfort index by publishing the
Final Rule on the Identification and Listing of Hazardous Waste (Wood Preserving)
that delineates as hazardous waste, wastewaters, process residuals, preservative
drippage, and discarded spent formulations from wood preserving processes at
facilities that currently use or have previously used chlorophenolic
formulations--F032 (55 FR 50450).
During the conduct of a routine environmental property audit at an
agricultural chemical dealer, four 55-gallon leaking drums of pentachlorophenol-
formulated pesticides were found. It could not be determined if the pesticide
was "spent" or unused formulation. Chemical analyses showed it to contain the
following constituents:
Pentachlorophenol 3.5%
Tetrachlorophenols 0.2%
Hexachlorobenzene 50 ppm
Polychlorodibenzoethers 100 ppm
TCDDs ND
TCDFs ND
PCDDs 5 ppb
PCDFs 20 ppb
HxCDDs 15 ppb
HxCDFs 30 ppb
HpCDDs 150 ppb
HpCDFs 320 ppb
OCDD 1000 ppb
OCDF 2000 ppb
One-hundred cubic yards of contaminated soil were found to contain
approximately 0.5% PCP, and concentrations of dioxins and furans (CDDs and CDFs)
were about ten percent of those indicated for the liquid pesticide. Because
discarded, unused formulations of pentachlorophenol (PCP) and tetrachlorophenols
(T4CPs) are considered RCRA-listed acutely hazardous F027 wastes, these waste
pesticides must be treated according to the RCRA Land Disposal Restriction Rule
(40 CFR 268.41) for "F" wastes, which requires treatment of the TCDDs, TCDFs,
PCDDs, PCDFs, HxCDDs, and HxCDFs to < 1 ppb for each homolog and < 50 ppb, < 50
ppb, <100 ppb, and < 10 ppb for 2,4,5-TCP, 2,4,6-TCP, 2,3,4,6-TCP, and PCP,
respectively. Two treatment methods currently can reduce this waste to below
these limits—high temperature incineration and chemical detoxification (Fuhr and
des Rosiers, 1988). However, no firm in the United States has the requisite RCRA
permits to perform this service on a routine basis; besides, the total volume of
four drums of liquid pesticide and 100 cubic yards of pesticide-contaminated soil
is too small to justify the high cost of incineration (> $1500 per drum for a
relatively simple, hazardous waste).
There are options that have practical merit and have been recommended and
employed, and these include: (a) on-site chemical detoxification under RCRA, and
(b) land application as a pesticide under FIFRA.
11
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(a) On-site chemical detoxification of the liquid pesticide,
The RCRA small quantity generator rule (40 CFR 161/162)
(U.S. EPA, 1986) can be employed for the on-site
treatment of < 1000 kg/month (see Table 7) without
having to obtain a RCRA permit. Potassium polyethylene
glycolate (KPEG) is used to detoxify (i.e., remove
chlorine) the liquid pesticide. The KPEG agent is
produced by reacting polyethylene glycol-400 (MW=400)
with potassium hydroxide (85% purity), removal of
aqueous waste, and dosing at 2.5 times the
organochlorine content of the pesticide formulation.
The temperature of the stirred reaction is maintained
between 70-120° C for at least 24 hours. Byproducts
produced are water soluble, biodegradable and have been
shown not to be toxic to aquatic organisms (des Rosiers,
1986) (des Rosiers, 1989) (Taylor, et al.. 1990).
Composite analyses of POHCs and CDDs and CDFs are
performed by a qualified analytical laboratory prior to
and after detoxification to assure compliance with RCRA
rules.
Regarding the 100 cubic yards of CDD-and CDF-
contaminated soil, OSWER policy requires cleanup to RCRA
standards if the 2,3,7,8-TCDD equivalency (TCDDe)
exceeds 1 ppb in residential areas or 20 ppb in
industrial sites (desRosiers, 1988). (Note that this
contaminated soil contains 15.7 ppb TCDDe calculated
using toxicity equivalent factors (TEFs) per the 1989
method) (Bellin and Barnes, 1989).
(b) Land application as a pesticide.
(This option has been previously discussed under
Conceptual Approach under FIFRA.)
12
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REFERENCES
Bell in, J.S. and D.G. Barnes (1989). Interim Measures for Estimating Risks
Associated with Exposures to Mixtures of Chlorinated Dibenzo-p-Dioxins and -
Dibenzofurans (CDDs and CDFs) and 1989 Update. Risk Assessment Forum.
EPA/625/3-89/016, March.
Collison, G.H. (1990). Waste Without a Place — the Pentachlorophenol Problem:
HMCRI, Superfund '90, Washington, DC, November 26-28, 446-9.
des Rosiers, P.E. (1986). APEG Treatment of Dioxin- and Furan-Contaminated Oil
at an Inactive Wood Treating Site in Butte, Montana. Paper presented at the
Panel on New and Emerging Technology, Annual Meeting of the American Wood
Preservers Institute, Washington, D.C., October 28.
desRosiers, P.E. (1988). General Approach Used by the Dioxin Disposal Advisory
Group (DDAG) Regarding Pentachlorophenol Waste (also PCBs). OSWER Dioxin
Disposal Advisory Group, November 15.
desRosiers, P.E. (1989). Chemical Detoxification of Dioxin-Contaminated Wastes
Using Potassium Polyethylene Glycolate. Chemosphere. 18 (1-6), 343-353.
Fuhr, H.S. and P.E. des Rosiers (1988). Methods of Degradation, Destruction,
Detoxification, and Disposal of Dioxins and Related Compounds, in: Pilot Study
on International Information Exchange on Dioxins and Related Compounds.
NATO/CCMS, Report No. 174, August.
Offutt, C.K. and J. O'Neill Knapp (1990). The Challenge of Treating Contaminated
Superfund Soil. HMCRI, Superfund '90, Washington, DC, November 26-28, 700-711.
Taylor, M.L., Wentz, J.A., Dosani, M.A. Gallagher, W., and Greeber, J.S. (1990).
Treating Chlorinated Wastes with the KPEG Process. ORD-RREL, EPA/600/S290/026,
July.
U.S. EPA (1986). Understanding the Small Quality Generator Hazardous Waste
Rules: A Handbook for Small Business. OSWER, EPA/530-SW-86-019, September.
U.S. EPA (1989a). Obtaining a Soil and Debris Treatability Variance for Remedial
Actions. Superfund LDR Guide #6A. OSWER Directive: 9347.3-06FS, July.
U.S. EPA (1989b). Obtaining a Soil and Debris Treatability Variance for Removal
Actions. Superfund LDF Guide #6B. OSWER Directive: 9347.3-07FS, December.
13
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Table 1. Pesticide Active Ingredients That Appear on the RCRA
"Acutely Hazardous Commercial Products" Lists (RCRA P List)
Hazardous
Pesticide Active Ingredients Waste No.
Acrolein POOS
Aldicarb P070
Aldrin P004
Allyl alcohol P005
Aluminum phosphide POOS
4-Aminopyridine POOS
Arsenic acid P010
Arsenic pentoxide P011
Arsenic trioxide P012
Calcium cyanide P021
Carbon disulfide P022
p-Chloroaniline P024
Cyanides (soluble cyanide salts) P030
Cyanogen P031
2-Cyclohexyl-4,6-dinitrophenol P034
Dieldrin P037
0,0-Diethyl S-[2-(ethylthio)ethyl] „ P039
phosphorodithioate (disulfoton, DiSyston )
0,0-DiethylR0-pyrazinyl phosphorothioate P040
(Zinophos )
Dimethoate P044
0,0-Dimethyl 0-p-nitrophenyl phosphorothioate P071
(Methyl parathion)
4,6-Dinitro-o-cresol and salts P047
4,6-Dinitro-2-cyclohexylphenol P034
2,4-Dinitrophenol P048
Dinoseb P020
Endosulfan P050
Endothall P088
Edrin P051
Famphur P097
Fluoroacetamide P057
Heptachlor P059
Hydrocyanic acid P063
Hydrogen cyanide P063
Methomyl P066
alpha-Naphthylthiourea (ANTU) P072
Nicotine and salts P075
Octamethylpyrophosphoramide (OMPA, P085
Schradan)
14
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Table 1. Pesticide Active Ingredients That Appear on the RCRA
"Acutely Hazardous Commercial Products" Lists (RCRA P List)
(continued)
Hazardous
Pesticide Active Ingredients Waste No.
Parathion P089
Phenylmercuric acetate (PMA) P092
Phorate P094
Potassium cyanide P098
Propargyl alcohol P102
Sodium azide P105
Sodium cyanide P106
Sodium fluoroacetate P058
Strychnine and salts P108
0,0,0,0-Tetraethyl dithiopyrophosphate P109
(Sulfotepp)
Tetraethyl pyrophosphate Pill
Thallium sulfate P115
Thiofanox P045
Toxaphene P123
Warfarin P001
Zinc phosphide P122
Pentachlorophenol F027
2,3,4,6-Tetrachlorophenol F027
2,4,5-Trichlorophenol F027
2,4,6-Trichlorophenol F027
2,4,5-Trichlorophenoxyacetic acid (2,4,5-T) F027
2,4,5-Trichlorophenoxypropionic acid F027
(Silvex)
Chlorophenolic Formulations from Wood F032
Preserving
Creosote Formulations from Wood Preserving F034
Inorganic Preservatives Containing Arsenic F035
or Chromium
15
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Table 2. Pesticide Active Ingredients Contained on the RCRA
"Toxic Commercial Products" (RCRA U) List
Hazardous
Pesticide Active Ingredients Waste No.
Acetone U002
Acrylonitrile U009
Amitrole U011
Benzene U019
Bis(2-ethylhexyl)phthalate U028
Cacodylic acid U136
Carbon tetrachloride U211
Chloral (hydrate) U034
Chlordane, technical U036
Chlorobenzene U037
4-Chloro-m-cresol U039
Chloroform U044
o-Chlorophenol U048
4-Chloro-o-toluidine hydrochloride U049
Creosote U051
Cresylic acid (cresols) U052
Cyclohexane U056
Cyclohexanone U057
Decachlorooctahydro-1,3,4-metheno- U142
2H,5H-cyclobuta[c,d]-pentalen-2-
one (Kepone, chlordecone)
l,2-Dibromo-3-chloropropane (DBCP) U066
Dibutyl phthalate U069
S-2,3-(dichloroallyl diisopropyl- U062
thiocarbamate) (diallate, Avadex)
o-Dichlorobenzene U070
p-Dichlorobenzene R U072
Dichlorodifluoromethane (Freon 12 ) U075
3,5-Dichloro-N-(1,1-dimethyl-2- U192
propynyl)benzamide (pronamide, Kerb)
Dichloro diphenyl dichloroethane (ODD) U060
Dichloro diphenyl trichloroethane (DDT) U061
Dichloroethyl ether U025
2,4-Dichlorophenoxyacetic, salts and U240
esters (2,4-D)
1,2-Dichloropropane U083
1,3-Dichloropropene (Telone) U084
Dimethyl phthalate U102
Epichlorohydrin (l-chloro-2,3-epoxypropane) U041
Ethyl acetate U112
Ethyl 4,4'-dichlorobenzilate (chlorobenzilate) U038
Ethylene dibromide (EDB) U067
Ethylene dichloride U077
16
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Table 2. Pesticide Active Ingredients Contained on the RCRA
"Toxic Commercial Products" (RCRA U) List (continued)
Pesticide Active Ingredients
Hazardous
Waste No.
Ethylene oxide U115
Formaldehyde U122
Furfural U125
Hexachlorobenzene U127
Hexachlorocyclopentadiene U130
Hydrofluoric acid U134
Isobutyl alcohol U140
Lead acetate U144
Lindane U129
Maleic hydrazide U148
Mercury U151
Methyl alcohol (methanol) U154
Methyl bromide U029
Methyl chloride U045
2,2'-Methylenebis (3,4,6-trichlorophenol) U132
(hexachlorophene)
Methylene chloride U080
Methyl ethyl ketone U159
4-Methyl-2-pentanone (methyl isobutyl U161
ketone)
Naphthalene U165
Nitrobenzene U169
p-Nitrophenol U170
Pentachloroethane U184
Pentachloronitrobenzene (PCNB) U185
Phenol U188
Phosphorodithioic acid, 0,0-diethyl, U087
methyl ester
Propylene dichloride U083
Pyridine U196
Resorcinol U201
Safrole U203
Selenium disulfide U205
1,2,4,5-Tetrachlorobenzene U207
1,1,2,2-Tetrachloroethane U209
Thiram U244
Toluene U220
1,1,1-Trichloroethane U226
Trichloroethylene R U228
Trichloromonofluoromethane (Freon 11 ) U121
Xylene U239
17
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Table 3. Pesticide Inert Ingredients Contained on the RCRA
"Toxic Commercial Products" (RCRA U) List
Hazardous
Pesticide Active Ingredients Waste No.
Acetone U002
Acetonitrile U003
Acetophenone U004
Acrylic acid U008
Aniline U012
Benzene U019
Chlorobenzene U037
Chloroform U044
Cyclohexane U056
Cyclohexanone R U057
Dichlorodifluoromethane (Freon 12 ) U075
Diethyl phthalate U088
Dimethylamine U092
Dimethyl phthalate U102
1,4-Dioxane U108
Ethylene oxide U115
Formaldehyde U122
Formic acid U123
Isobutyl alcohol U140
Maleic anhydride U147
Methyl alcohol (methanol) U154
Methyl ethyl ketone U159
Methyl methacrylate U162
Naphthalene U165
Saccharin and salts U202
Thiourea U219
Toluene U220
1,1,1-Trichloroethane U226
1,1,2-Trichloroethane R U227
Trichloromonofluoromethane (Freon 11 ) U121
Vinyl chloride U043
Xylene U239
18
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Table 4. Predicted Treatment Effectiveness for Contaminated Soil *
^^
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— technology
Treatability Grout*1*^
Non-Polar Halogenated
Aroma tics
(W01)
PCBs, Halogenated
Dioxins, Furans, and
Their Precursors
(W02)
Halogenated Phenols,
Cresols, Amines, Thiols,
and Other Polar
Aroma tics (W03)
Halogenated
Aliphatic Compounds
(W04)
Halogenated
Aliphatics, Ethers,
Esters, and Ketones
(W05)
Nitrated Conpoonds
(W06)
Heterocyclics and
Sample Non- Halogenated
Aromatics
(W07)
Polynuclear
Aromatics
(W08)
Other Polar
Non- Halogenated
Organic Compounds
(W09)
Non-Volatile
Metals
(W010)
Volatile
Metals
(W11)
Thermal
Destruction
•
• 3
•
•
•
•
•
•
O1
X1
Oechlor-
i nation
A
A
A
A
A1
o1
O2
o2
o2
Qi
Qi
Bioremed-
i at ion*
3
A
A
A
A2
A1
•
•
•
•
0 x1
0 x1
Low Temp
Thermal
Oesorption
• A
•V
A
•
O1
o1
•
o
A
O1
O1
Chemical
Extraction
& Soil
Washing
A
A
A
A
A1
A
A
3
A
A
A
A
Immobi 1 i -
zation*
A
i
A
A
A
A1
A1
A2
A
A
•
•
Demonstrated Effectiveness
Potential Effectiveness
No Expected Effectiveness (no
expected interference to process)
No Expected Effectiveness (potential
adverse effects to environment or process)
(Offut and Knapp, 1990).
1 Data were not available for this treatability group.
Conclusions are drawn from data for compounds with
similar physical and chemical characteristics
1 High removal efficiencies may be due to volatilization
or soil washing
1 The predicted effectiveness may be different than the
data imply due to limitations in the test conditions
4 These technologies may have limited applicability to high
levels of organics
19
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Table 5. Examples of Where RCRA-Listed Pesticides May Fit in
Treatability Groups
Pesticide
Treatability Group
o-Dichlorobenzene
Halogenated Non-Polar Aromatic
Compounds (W01)
Silvex, 2,4,5-T
PCBs, Halogenated Dioxins, Furans
and their Precursors (W02)
or
Halogenated Phenols, Cresols,
Amines, Thiols, and other Polar
Aromatics (W03)
Pentachlorophenol
Halogenated Phenols, Cresols,
Amines, Thiols, and other Polar
Aromatics (W03)
l,2-Dibromo-3-ch!oro-
propane (DBCP)
Halogenated Aliphatic Compounds
(W04)
Endosulfan
Halogenated Cyclic Aliphatics/
Ethers/Esters/Ketones (W05)
Toxaphene
Halogenated Cyclic Aliphatics/
Ethers/Esters/Ketones (W05)
Dinoseb
Nitrated Aromatic & Aliphatic
Compounds (W06)
Aniline
Heterocyclics and Simple Non-
Hal ogenated Aromatics (W07)
Naphthalene
Acrolein
Polynuclear Aromatics (W08)
Other Polar Organic Compounds (W09)
20
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Table 6. Alternate Treatability Variance Levels for Contaminated
Soil and Debris.*
Structural
Functional
Group
Halogenated
Non- Polar Aromatics
Dioxins
PCBs
Herbicides
Halogenated
Phenols
Halogenated
Aliphatics
Halogenated
Cyclics
Nitrated
Aromatics
Heterccyclics &
Non-Halogenated Aromatics
Polynuclear
Aromatics
Other Polar Organics
Concentration
Range (ppm)a
0.05
0.00001
.01
0.002
0.5
0.5
0.5
2.5
0.5
0.5
0.5
- 10
- 0.05
- 10
-0.02
- 40
- 2
- 2
- 10
- 20
- 20
- 10
Threshold Percent
Concentration Reduction
(ppm)a Range
100
0.5
100
0.2
400
40
200
10,000
200
400
100
90
90
90
90
90
95
90
90.9
90
95
90
- 99.9
-99.9
- 99.9
-99.9
- 99
-99.9
- 99.9
- 99.99
- 99.9
- 99.9
-99.9
Structural
Functional
Group
Antimony
Arsenic
Barium
Chromium
Nickel
Selenium
Vanadium
Cadmium
Lead
Mercury
Concentration
Range
0.1 -
0.27 -
0.1 -
0.5 -
0.5 -
0.005
0.2 -
0.2 -
0.1 -
0.0002 -
(ppm)D
0.2
1
40
6
1
22
2
3
0.008
Threshold Percent
Concentration Reduction
(ppm)b
2
10
400
120
20
0.08
200
40
300
0.06
Range
90
90
90
95
95
90
90
95
99
90
- 99
-99.9
- 99
- 99.9
- 99.9
- 99
- 99
- 99.9
- 99.9
- 99
* If the constituent concentration of the untreated waste is less than the
threshold concentration, use the concentration range; if it is more than
the threshold concentration, use the percent reduction range.
a Total Waste Analysis
b TCLP Analysis
21
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Table 7. Categories of Hazardous Waste Generators
(40 CFR 161/162)
KEY: 1 barrel = about 200 kilograms of hazardous waste
which is about 55 gallons
Generators of No More
Than 100 kg/mo
If you generate no
more than 100 kilgrams
(about 220 pounds or
25 gallons) of
hazardous waste and no
more than 1 kg (about
2 pounds) of acutely
hazardous waste in any
calendar month, you
are a conditionally-
exempt small quantity
generator and the
federal hazardous
waste laws require you
to:
• Identify all
hazardous waste
you generate.
• Send this waste to
a hazardous waste
facility, or a
landfill or other
facility approved
by the state for
industrial or
municipal wastes.
• Never accumulate
more than 100 kg
of hazardous waste
on your property.
(If you do, you
become subject to
all the require-
ments applicable
to 100-1000 kg/mo
generators ex-
plained in this
handbook.
100-1000 kg/mo
Generators
If you generate
more than 100 and less
than 1000 kg (between
220 and 2,200 pounds
or about 25 to under
300 gallons) of
hazardous waste and no
more than 1 kg of
acutely hazardous
waste in any month,
you are a 100-1000
kg/mo generator and
the federal hazardous
waste laws require you
to:
• Comply with the
1986 rules for
managing hazardous
waste, including
the accumulation,
treatment, storage
and disposal re-
quirements de-
scribed in this
handbook.
Generators of
1000 kg/mo or more
If you generate
1000 kg (about 2,200
pounds or 300 gallons)
or more of hazardous
waste, or more than 1
kg of acutely
hazardous waste in any
month, you are a
generator of 1000
kg/mo or more and the
federal hazardous
waste laws require you
to:
• Comply with all
applicable
hazardous waste
management rules.
22
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Research and Development Needs For Agrichemical
Retail Dealership Site Assessment and Remediation
by
Chris Myrick
Director of Legislative and Regulatory Affairs
National Agrichemical Retailers Association
INTRODUCTION
Why is research and development needed for the assessment and remediation
of agrichemical dealerships?
Over the last few decades, many agrichemical dealers have slowly, and in
most cases, inadvertently contaminated the soil at their dealerships with many
different pesticide, fertilizer, and solvent products. As a result of this
contamination, one of the most uncertain and ominous issues now facing the
agrichemical industry is the cleanup of contaminated soils and water at retail
agridealer facilities.
Currently, agridealers have very limited and expensive options available
to them for the cleanup of contaminated soil and water. For example, if the soil
at a dealership contains pesticide waste regulated under the Resource
Conservation and Recovery Act (RCRA), estimates indicate that it could cost a
dealer from three to five million dollars to cleanup his facility. In addition,
a large data gap now exists with respect to the remediation of chemically
contaminated soils and water at retail facilities that prohibits regulators from
reviewing the viability of new and more cost effective procedures.
It is the goal of the agrichemical community to work in concert with
federal and state regulatory officials as well as private and government research
scientists to develop new and acceptable site assessment and remediation
technologies that dealers can economically apply to their operations. Over the
next few pages, I would like to review several areas of research and development
that the agrichemical industry deems critical to addressing the site
contamination problem.
RESEARCH AND DEVELOPMENT IN SITE ASSESSMENT
Development of Preliminary Site Assessment Procedures That Can Be Undertaken
bv a Retail Dealer
Today, an environmental consultant hired by a dealer to do a site
assessment must report contamination, if found, to the State authorities. This
requirement is currently prohibiting many dealers from moving forward with any
corrective action because of the fear of bankruptcy and the high cost of a
consultant.
23
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It is the position of the National Agrichemical Retailers Association
(NARA) that the development of visual as well as preliminary sampling procedures
that can be carried out by retail dealers will help the industry move forward in
discovering and correcting contaminated sites.
Specific Research Needs:
• Development of guidelines that can be used in a historical records
check of a facility. These guidelines would help pinpoint specific
practices or evidence that would indicate high probability of
contamination.
• Development of guidelines for visual site assessment procedures
based on vegetative state, soil decolorization, proximity to wells
and ditches, etc.
• Development of preliminary sampling procedures that can be carried
out by a retail dealer.
Development of Sampling Technology That Is Centered on the Unique
Characteristics of Agrichemical Facilities
Sampling soils and water that may be contaminated with pesticides,
fertilizers and solvents is a very complex task. Even though there is a minimal
amount of research going on in this area at this time, much more research must
be carried out in order to gain a better understanding of how to sample soils
with a mixture or high concentration of wastes. Not only will sampling
technologies have to concentrate on waste mixtures, they will also have to take
into consideration soil type, hydrogeology and potential for constituent(s) to
leach.
Specific Research Needs:
• Research aimed at establishing the validity of a variety of
different extraction procedures and their relationship to
constituent leaching potential.
• Research aimed at developing low cost procedures that are workable
on soil containing a mixture of constituents. This sampling
technology could accurately assess soils containing mixtures of
Carbamates, Chlorinated Hydrocarbons, Triazines, Organophosphates,
Organic Nitrogen Pesticides, Chlorophenoxy Acids, and other
pesticide and fertilizer constituents.
• Development of standardized analytical procedure which would
stimulate leaching or predict the degree of downward migration of
agrichemical contaminates by actually testing soils from
contaminated sites. This may be generically comparable to the E.P.
Toxicity or TCLP procedure.
24
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Development of Remediation Trigger Levels Based on Risk Assessment
It has been discovered through site assessment activities already
undertaken that individual agrichemical facilities possess unique
characteristics. These unique characteristics in many cases may require that
regulators establish trigger levels on a facility by facility basis.
In the establishment of these individual trigger levels, regulators must
now set them conservatively because of the limited amount of information
regarding the risk that single or multiple waste mixtures present in different
soil and hydrogeologic situations.
The development of remediation trigger level standards is of utmost
importance to the entire agrichemical industry cleanup initiative.
Specific research needs:
• Development of risk assessment model which would accurately assess
different constituents based on actual sampling, predicted leaching
potential, and individual facility characteristics.
• Development of remediation trigger levels based on model
predictions. These predictions would be based on health hazard
constituent(s) present and potential to leach into ground water at
each individual location.
Development of Micro-Economic Cost Analysis Formula That Can Be Used on a
Site-Bv-$ite Basis
The cost of site assessment activities are of great importance to the end
goal of cleaning up contaminated sites. Agrichemical dealers typically operate
on a small margin which leaves little funding for site assessment and remediation
cost.
The development of micro-economic cost analysis formula that may be used
by agrichemical dealers, consultants, and regulators would be of great benefit
in determining whether a particular facility is financially capable of the
cleanup recommended. This formula would also be very helpful when cleanup costs
must be spread over a prolonged period of time.
Specific research needs:
• Development of site assessment cost data base which takes into
consideration multiple site assessment technologies based on
individual site characteristics.
• Development of linear programming model which considers basic
facility characteristics and gives lowest cost site assessment
procedure based on those characteristics.
• Development of financial data base which will be used to give lowest
cost site assessment technology and individual facility financial
capability.
25
-------
RESEARCH AND DEVELOPMENT IN SITE REMEDIATION
Development of Soil Cleanup Levels
The discovery of soil and water cleanup levels that mitigate risk are
important to the cleanup objectives of the agrichemical industry and regulators.
Even though water cleanup levels are already specified through Maximum
Contaminate Levels and Health Advisories in many cases, cleanup levels for soil
are much more ambiguous.
Some basic research is already being conducted regarding the establishment
of soil cleanup levels based on contaminate concentration, leaching potential,
soil characteristics and hydrogeology. However, much more research must be
conducted in order to gain a more accurate picture of the risk that different
mixtures and concentrations of contaminants present under various conditions.
Specific Research Needs:
• Development of attainable soil cleanup levels (thresholds) that take
into consideration individual constituents and constituent mixtures.
These cleanup levels must meet risk/benefit analysis criteria that
take into consideration the facility's ability to finance cleanup as
well as the actual hazard that the waste present.
Development of Low Cost Remediation Technology
According to a review of literature on remediation technology, not much is
known about the workability of current technology as it relates to agrichemicals.
From preliminary cost estimates of technology currently being used however, it
is evident that new in-situ low cost technologies must be developed in order for
the agrichemical industry to cleanup contaminated sites and remain economically
viable.
Because of the wide variety of chemical constituent mixtures currently
present in dealership soils, researchers must take into consideration the
regulatory implications of technological innovations. For example, waste
regulated under RCRA cannot be treated in the same manner as waste that is not
regulated under RCRA or special state laws. Research must be directed at finding
low cost remediation technology that can be carried out by the dealer or
consultant.
Specific Research Needs:
• Development of onsite remediation technologies that can be carried
out by the agridealer under regulatory agency supervision. These
remediation technologies must be proven capable of attaining the
cleanup objectives of regulatory agencies while remaining low in
cost.
• Development of a remediation technology data base that takes into
consideration laws governing remediation activities.
26
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Development of Micro-Economic Cost Analysis That Can be Used on a
Site-bv-Site Basis
As was the case for site assessment, the development of a Micro Economic
cost analysis formula for the remediation of agrichemical facilities would be
very helpful in projecting the short- and long-term cost of remediation
activities.
Understanding remediation cost and weighing different remediation methods
based on cost would be extremely helpful in insuring the continued financial
security of the entire agrichemical industry.
Specific Research Needs:
• Development of a remediation cost data base which includes
remediation cost information on contaminating constituents, leaching
potential, soil and water cleanup objectives, and technology used.
• Development of linear programming model which can be used by
individual dealers, regulatory officials, lending institutions, and
insurance companies in determining the financial capability of a
facility to successfully carry out remediation activities.
27
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An Evaporation /Degradation System for Pesticide Equipment Rinse Water
by
Steven E. Dwinell
Environmental Specialist
Pesticides and Data Review Section
Florida Department of Environmental Regulation
INTRODUCTION
In the 1985-86 a system for the evaporation/degradation was developed
jointly by our Department and the University of Florida Agricultural Engineering
Department to provide a viable option for the disposal of rinsewater from
pesticide application equipment. This system was based on work done in the
1970's by Charles Hall and others at Iowa State University on pesticide
degradation pits. This system does not use new technology but is an attempt to
apply a workable technology in an environmentally acceptable manner in an
economical way. It has almost been successful.
The system itself is quite simple. It consists of an above-ground tank
(or, if the tank is below grade, a double tank), a covered wash down slab, and
a system of transferring rinsewater containing pesticide residues from the slab
to the tank. The tank contains a soil or gravel matrix and is covered with a
clear fiberglass or glass roof. The pesticide rinsewater is adsorbed by the soil
matrix, the liquid portion evaporated by sunlight, and pesticides in the
rinsewater degraded by microorganisms in the matrix. There is no discharge from
the system. A secondary containment system is used to protect against leaks.
Attached are several figures and tables that describe the system. These figures
are taken from the Institute of Food and Agricultural Sciences Bulletin 242.
The basic components of the system in Florida are:
Above-ground or double walled tank.
Clear roof over tank.
Covered wash down slab.
Transfer system for water from slab to tank
with option for storage capacity.
The keys to successful operation in Florida are:
Optimized evaporation.
Containment of rinsewater discharged into system.
Protection of evaporation/degradation tank from rainfall.
28
-------
These are achieved by:
Evaporation
Maximizing surface area of tank and sizing tank for different parts
of the state. The size of the surface area of the tank is decided
based on the amount of water to be discharged to it. Tables 1 and
2 of Bulletin 242 provide the figures for calculating the
appropriate surface area.
Using a clear roof. Clear fiberglass, glass, or other green house
roof materials can be used.
Using a rinsewater distribution system that avoids film formation
that could impede evaporation. This distribution system consists of
a vertical pipe that conducts the rinsewater through the media to
the bottom gravel layer of the tank. The rinsewater then moves up
vertically through the media. (See Figure 2 from Bulletin 242).
Requiring setback from structures to aid airflow.
The evaporation/degradation tanks are required to be built a minimum
of seventy-five (75) feet from other structures to avoid
obstructions to air flow.
Containment
Above-ground tank for leak inspection. The tank must be a minimum
of eight inches off the ground to allow for inspection for leaks.
If the tank must be below grade, a double tank must be used with an
automatic leak alarm and pump system.
Lined pad and sump. Both the wash down pad and the sump are lined
to prevent leaks to underlying soil. The sump must also be pumped
dry at the end of each day of operation.
Secondary containment. A berm is required around the evaporation
/degradation tank to provide for secondary containment should the
tank fail. The bermed area is also covered by a roof and is lined.
Alarm system. An alarm system and pump cutoff switch is required to
prevent overfilling the tank when pumping water from the wash down
slab to the tank.
Rainfall protection
Fixed roof over tank and secondary containment. A roof covers both
the tank and the bermed area to prevent rain from filling this area.
Cover over slab - fixed or moveable. A low profile moveable cover -
such as a swimming pool cover - can be used to prevent rain from
getting onto slab, but a fixed roof is preferred.
29
-------
Roof design - 30 degree overhang. The roof must have a minimum
thirty degree overhang measured from the edge of the pad or the
berm, in order to prevent rain from blowing into theses areas in
significant quantities. (See Figure 1 of Bulletin 242.)
Two questions that were addressed early on in the process of development
of this system were air emissions and the rate of degradation of the pesticides
added to the system. The question of air emissions was resolved based on data
developed in the Iowa State studies that showed only very low detections of
pesticides downwind from the degradation pit. Also, it was decided that air
emissions from the degradation tank would have to be much less than air emissions
from an application site, since the concentration of the pesticide solution
discharged to the tank was two orders of magnitude less than the concentrations
used in applications.
It was also decided that the degradation rate of the pesticides placed into
the system was not important, since there was no discharge from the system, and,
therefore, even slow rates were not a concern.
IMPLEMENTATION
The goal of implementation was to make this system economically feasible
by minimizing permit and regulatory costs. In order to do this, it was important
to: avoid high costs for permits, a requirement for a professional engineer seal,
and high costs for compliance with applicable regulations.
This was accomplished by:
• Obtaining an exemption from the RCRA facility permit initially
• Developing a general permit that
- did not require engineer seal
- did not require record keeping
- did not require monitoring
• General permit did specify:
- certain components
- operation
- closure requirements
Deviations from the components and specifications in the general permit not
allowed.
A publication, Institute of Food and Agricultural Sciences (IFAS) Bulletin
242, was developed which described construction and operation in terms that
average farmer could understand and use.
The state regulation allowing the construction and operation of these
systems, DER Rule Chapter 17-28.822 was adopted in June 1988. The designation
of this rule was changed in 1989 to Chapter 17-660.802, but language of the rule
was not changed.
Currently there are three systems permitted under this rule - one each in
1988, 89, 90. Two of them are at research farms, one is at a golf course.
30
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Experience
The systems have proven to be more expensive than originally estimated,
with costs of about thirty to fifty thousand dollars per system. They have also
been capable of handling more water than estimated, about double what was
estimated. The pesticide users have found the systems to be very useful and
helpful in their operations, and other applicators are interested in using these
systems,
Regulatory Problems
In late 1989 we became aware that a new interpretation of RCRA exemption
for waste water treatment units had been made. This new interpretation requires
that treatment systems must have either a RCRA permit or Clean Water Act ( known
as a National Pollution Discharge Elimination System - NPDES) permit. Since the
NPDES permits apply only to facilities that discharge, these systems can not
obtain an NPDES permit. The Farmer's Exemption under RCRA also may not apply to
these systems.
Current options for maintaining the economic feasibility of these systems are:
• Pursue RD&D permit through Technology Innovation Program
• Petition EPA for regulatory relief
• Petition Congress for exemption
CONCLUSION
The evaporation/degradation system is a promising technology and a good
option for pesticide waste management that is being hampered primarily by current
regulations and their interpretation, not because of environmental shortcomings.
This is a system that can be utilized now, without years of research and
development, but that will require innovative regulatory action to become a
useful option for pesticide users.
31
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Pesticide Disposal Using a Demulsification, Sorption,
Filtration and Chemical and Biological Degradation Strategy
By
D. E. Mull ins, Department of Entomology
R. W. Young, Department of Biochemistry and Nutrition
G. H. Hetzel, Department of Agricultural Engineering
D. F. Berry, Department of Crop and Soil, Environmental Sciences
Virginia Polytechnic Institute and State University
Blacksburg, Va. 24061
ABSTRACT
Research concerning disposal of pesticide-laden solutions, including
emulsions or particulate suspensions (wettable powders and flowables), has
focused on concentration and/or containment methods using biodegradable
lignocellulosic sorbents. Contaminated sorbents are used as a matrix on which
the pesticides are degraded in a composting environment. In laboratory studies,
significant amounts of selected pesticides were removed from solutions (ranging
in concentrations from 1,250 to 20,000 mg/kg) by a combination of
demulsification, sorption and filtration in the presence of lignocellulosic
materials. In other studies, high concentrations of diazinon and other
pesticides were degraded rapidly in a nutrient-enriched lignocellulosic medium.
Based on our research, a pesticide disposal system is currently under
development that should prove to be practical, effective, safe and relatively
inexpensive. It is envisioned that this pesticide disposal method will be
useful in a variety of agrichemical situations.
INTRODUCTION
It is important that pesticide waste disposal methods be developed because
inappropriate handling may result in soil contamination at mixing and pesticide
handling sites. Failure to properly handle pesticides at these sites can result
in groundwater contamination (Myrik, 1990; Norwood, 1990). Minimization of waste
by rinsate recycling and spraying on treatable areas under many circumstances is
a reasonable and effective means for rinsate disposal. However, there is still
a need for practical, inexpensive, and effective methods for disposing of small
volumes of concentrated and dilute pesticide wastes. A variety of potential
technologies suitable for pesticide waste disposal have been examined, but few,
if any, satisfactory methods are available to pesticide users. (Bridges, 1988;
Norwood, 1990). It has been difficult to develop a general disposal method
because many of the pesticidal materials that are available have unique chemical
and formulated characteristics. As a result, development of "universal" disposal
techniques is problematic.
According to Ware (1989), there are currently about 200 active pesticidal
ingredients formulated in an estimated 37,000 formulations, and 75% of pesticides
used are liquid sprays. Emulsifiable concentrates, wettable powders, soluble
liquids, and suspension concentrates represent the most common formulations used
in liquid sprays (Ware, 1989; Seaman, 1990). Among these, emulsifiable
concentrates, wettable powders and soluble liquids are the most commonly used but
32
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suspension concentrates, capsule emulsions, water-dispersible granules, emulsions
in water and suspoemulsions may increase in usage at the expense of the more
traditional formulations (Seaman, 1990). Future trends in formulation
development and availability will be significantly influenced by regulatory
pressures resulting from reassessment of inert ingredients used in formulations
(Seaman, 1990; Thomas, 1990). Because of this, it would appear that development
of pesticide waste disposal strategies must take into account current and future
trends in pesticide formulation chemistry. The pesticide waste disposal strategy
described here is designed to remove pesticides from a variety of aqueous
formulations and dispose of them using chemical and biological degradation.
DISPOSAL STRATEGY
We have proposed a conceptual/functional model for pesticide wastewater
disposal (Hetzel, et al., 1989). A modified version is presented in Figure 1.
The disposal process is divided into a sorption and a disposal phase. The
sorption phase includes addition of demulsification agents and lignocellulosic
materials (peat moss, wood products). During this phase, solubilized
pesticides are removed from the rinsate solution and concentrated onto the
organic sorbents. We have found that addition of demulsifying agents facilitate
the sorption process when treating various emulsifiable concentrate formulations
(Judge et al., 1990). The disposal phase involves physical separation of the
pesticide-laden sorbents and suspended pesticide particulates (derived from
wettable powders, flowables, etc.) from the aqueous phase. The aqueous phase may
then be recycled or discarded. The solid phase containing pesticides sorbed onto
the lignocellulosic matrices and/or particulates removed from pesticidal
particulates are then placed into a composting environment where the pesticides
are chemically and biologically degraded. Lignocellulosic materials have been
selected for use in disposal processes because they are relatively inexpensive,
have been found to be highly sorbent, and may serve to support or enhance
biodegradation activities. We have selected three such materials for study.
Peat moss is a highly sorbent material which is readily available and relatively
inexpensive. Because peat does not contain readily degradable carbohydrates,
addition of high energy substrates (corn meal) is added to enhance solid
substrate fermentation activities. Ground pine bark mulch is included in our
studies because it has been found to sorb some pesticides effectively.
Steam-exploded wood fibers (Overend and Chornet, 1987) were selected not only
because of their potential as effective sorbents, but also because of their
potential to support solid substrate fermentation with a reduced requirement of
nutrient enrichment.
The effectiveness of composting as a means for hazardous waste management
has been recently reviewed (Hart, 1991). Composting occurs widely in nature
and as a process is being employed to dispose of municipal sewage sludge wastes
(Hart, 1991; Parr, et al., 1978) and its potential to cleanup contaminated soil
sites is being examined (Williams and Myler, 1990). The use of composting as a
means for degrading pesticides is shown Figure 2. It illustrates a hypothetical
situation where a pesticide contained in a composting environment can be degraded
to relatively low levels. The degradation may be due to direct metabolism or
cometabolism of the pesticide by the various composting microorganism
populations. With time, the compost cycles from high to lower energy content,
and microbial population dynamics will change reflecting the nutritional changes
in substrate availability. In situations where the initial pesticide
concentration is low, or where a pesticide is easily degraded, one .feeding or
33
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compost cycle may be sufficient to reduce the pesticide to low levels. However,
under circumstances where the pesticide concentrations may be high, or under
circumstances where they are not easily degraded, additional energy input may be
required. Figure 2 includes three feeding cycles (nutrient addition) increasing
the energy level of the compost at each addition. During each cycle as the
temperature increases and then decl ines, the metabol ic activities of thermophil ic
and mesophilic microbial populations will also cycle. The strength of solid
substrate fermentation as a method of pesticide disposal is that it relies on a
consortia of degrading microbes and not just one species. Under these
conditions, rates of pesticide degradation are expected to be enhanced since the
combined activities of a diverse microbial population is expected to be more
efficient.
EXPERIMENTATION
Laboratory experiments have been conducted using approaches designed to
reflect what is envisioned as applicable to development of a field prototype
disposal unit. A variety of systems have been evaluated and the system selected
for our studies includes mixing samples containing pesticide solutions and
sorbents in an Erlenmeyer flask using a magnetic mixer or shaking table, followed
by settling and filtration. In our initial experiments, pesticide-laden sorbent
material was filtered sorbent material was filtered through Whatman filter paper
using a vacuum system. Currently, we are using a filtration system consisting
of polyvinyl chloride (PVC) columns [3/4 in (dia) x 12 in (length)] fitted with
a PVC coupling containing a stainless steel screen (40 mesh) 15 grams of fine
sand and several layers of filter paper. Samples were taken at different stages
of the sorption process and analyzed. Solvents used in this study were pesticide
grade.
The general pesticide extraction and analytical procedures used are
described by Walls (1981). Analytical standards were obtained from the U.S.
Environmental Protection Agency Pesticide and Industrial Chemicals Repository
MD-8, Research Triangle Park, NC. Depending upon the pesticide, several
different solvents were used as extractants (ie. acetone, hexane, etc.). We also
used sonication as a means to improve extraction efficiencies.
Following various purification and volume reduction procedures samples were
analyzed using gas-liquid chromatography. Sorbents tested include sphagnum peat
moss, steam-exploded yellow poplar wood fibers (1. water and alkaline washed;
2. bleached), and pine bark mulch. All lignocellulosic materials were ground in
a Wiley mill using a 2 mm screen). Activated carbon (Calgon FiltrasorbR 200) was
used as the comparison sorbent material (control).
RESULTS AND DISCUSSION
Sorption phase
Table 1 summarizes information obtained when peat moss was mixed with
various concentrations of Diazinon AG500 and Dursban 4E for 24 hours. Removal
of diazinon from solution was effective at all concentrations tested, however,
removal of chlorpyrifos, was not effective at the higher (20,000 & 10,000 mg/kg)
concentrations tested (Hetzel, et al., 1989). Experiments with other
emulsifiable concentrate formulations using similar protocols, provided variable
34
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removal rates. During these preliminary studies, we observed that emulsions
persisted after mixing the pesticidal emulsifiable concentrates with peat moss.
Studies using a fluorescent probe, emulsifiable concentrate blanks and
emulsifiable concentrate pesticide formulations (chlorpyrifos, diazinon, and
malathion) revealed that addition of calcium hydroxide was an effective
demulsification agent. We have found that the use of calcium hydroxide in the
presence of peat moss greatly increased the rate of removal for several
pesticide formulations from aqueous suspensions (Judge, et al., 1990).
Table 1. Sorption of Diazinon as Diazinon AG 500 and Chlorpyrifos as Dursban
4E at Several Concentrations after Mixing with Peat Moss for 24 Hours
Pesticide Remaining in Solution1'2'3
(percent of initial concentration)
Formulated
Concentration 20.000 10.000 5.000 2.500 1.250
Pesticide
Diazinon 1.4 ± 0.8 0.7 + 0.1 1.0 ± 0.7 6.0 ± 0.8 3.0 ± 0.6
Chlorpyrifos 45 ± 6 19.0 ± 11 5.3 ±5 2.4 ± 2.0 7.6 ± 4.6
1 Actual initial concentrations for diazinon averaged 92 ± 6% of the intended
formal ation.
10 grams of sphagnum peat moss were mixed in 200 ml pesticide containing
solution on a magnetic stirrer.
3 Percentage of remaining concentration represented as the mean ± standard
error.
4 For details see Hetzel et al., 1989.
Table 2 contains information which we have obtained using a one-step
demulsification, sorption and filtration process on 10 pesticide formulations and
four sorbents. In a effort to represent what might occur in the field, we have
used high initial pesticide concentrations (approximately 5000 mg/kg) in our
laboratory experiments. Data provided in Table 2 indicates that in most cases,
we were able to significantly reduce the amount of pesticide contained in test
solutions using the demulsification, sorption, and filtration procedure. It is
important to note that under certain circumstances, sorption may only contribute
insignificantly to pesticide removal. Some of the pesticides are quite unstable
in alkaline solutions (ie. captan, folpet, malathion, etc; Hartely and Kidd,
1987) and as a result may be degraded in the demulsification process. Extraction
of the sorbent material indicated that this was the case for certain pesticides,
since little material was recovered from the sorbents (data not shown). Also,
large amounts of the pesticides formulated for use as particulate suspensions
(wettable powders and flowables), can be removed by filtration. When filtered
35
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residues containing the participate and sorbent phase obtained from experiments
on these formulation types were extracted, measurable quantities of residues
could be detected in these extracts (data not shown). Most of the pesticides
tested are not very soluble in water, and as a result are sorbed onto hydrophobic
sorbent sites if they are not physically removed (filtration) or chemically
degraded (alkaline hydrolysis). Comparatively large amounts of metolachlor
remained in solution after one step treatment (Table 2). Since metolachlor
is somewhat soluble in water and not significantly transformed by alkaline
treatment, additional treatment will be required for effective wastewater cleanup
of this compound. It is possible that lignocellulosic materials could be
modified in such a manner that they might be capable of binding more water
soluble materials such as 2,4-D, metolachlor and alachlor. We are currently
investigating the possibility of modifying steam-exploded wood fibers to improve
specific sorptive properties in a manner similar to that described by MacCarthy
and Djebbar (1986) for chemical modification of peat.
Table 2. Removal of Pesticides from Aqueous Suspensions of Various Pesticide
Formulations Using Demul si fi cation, Sorption, and Filtration
% Pesticide remaining1'1'1
Compound/
Formulation
Atrazine (EC)
Azinphos-methyl (WP)
Captan (WP)
Carbofuran (F)
Chlorpyrifos (EC)
Diazinon (EC)
Folpet (WP)
Lindane (EC)
Malathion (EC)
Metolachlor (EC)
Wood
Fibers
1.0±0.6
0.0±0.0
O.OtO.O
0.5±0.4
2.4±0.8
1.5±1.3*
O.OtO.O
0.2±0.1
0.9±0.6*
9.9±2.8
Activated
Carbon
0.6±0.4
1.3±0.1
0.0±0.0
0.3±0.1
O.OtO.O
0.1±0.1*
O.OtO.O
O.OtO.O
O.QiO.O*
5.9±1.1
Pine
Bark
1.2±0.6
-
O.OtO.O
-
12±0.6
2.U2.2
O.OtO.O
-
O.OtO.O*
13.6±8.7*
Peat
Moss
1.2±0.2
O.OtO.O
4.9±1.1
S.ltl.O*
2. Oil. 4
0.7±0.0
0.1±0.1
O.OtO.O*
39.6±8.7
1 Initial formulated concentration of pesticide solutions was approximately 5000 mg/kg, the percentages were
calculated as changes from initial concentration after treatment. Means and standard errors are based on
3 replicates. Quantitation limits were set at 1 mg/kg.
1 100 ml of solution was mixed with 2.5 grams sorbent and 1 gram calcium hydroxide on a shaking table for 4
hours (or 24 hours as indicated by an asterik). The solution was allowed to settle (30 min) followed by
filtration in PVC columns.
1 Formulations used were as follows: atrazine as AATREX" (SOX ai), azinphos-methyl as Guthion" (35% ai), captan
(49% ai), carbofuran as Furadan" (40.631), Chlorpyrifos as Oursban" (44.4X ai), diazinon (48% ai), folpet
(SOX ai), lindane as Ortho" (20X ai), malathion as Dragon" (SOX ai) and metolachlor as Dual" (68.4X ai).
Emulsifiable concentrates (EC), flowable (F) and wettable powders (WP).
36
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Since applicators may choose to mix and apply some pesticides
simultaneously, as in some orchard pest control operations, we conducted an
experiment using an insecticide (azinphos-methyl) and a fungicide (captan) to
examine the efficacy of the system we are developing to remove high levels of
these two pesticides. The results of this experiment are shown in Table 3. The
effects of alkaline addition on the stability of captan and azinphos-methyl are
quite striking. When no calcium hydroxide was present about 1000 mg/kg of both
pesticides remained in solution after filtration. Treatment of the pesticide-
laden solution with calcium hydroxide essentially obliterates both of the
pesticides (control with calcium hydroxide). When these pesticides are mixed
with the demulsifying agent in the presence of sorbents, small amounts of captan
were detected in the filtrate. It is possible that the presence of the sorbents
influences the alkaline degradative process. Sorbents mixed with calcium
hydroxide seem to have lowered the amount of azinphos-methyl retained in the
filtrate. From these results it appears that the use of calcium hydroxide has
utility in the one-step process even though both of the formulations were
particulate suspensions.
We envision that acceptable levels of pesticide removal should be in low
mg/1 (0 to 9 mg/1) range and lower before the treated rinsate can be safely
discarded. Since the system which we have been developing using a one-step
process can reduce the levels of pesticide to a very low percentage of the
initial concentration, (Table 2) we have begun to experiment with a two-step
process. This process includes a first step similar to the one-step process
where sorbent and a demulsifying agent are mixed with the pesticide waste
solution. Instead of filtering the solution, it is then cycled through a column
containing additional sorbent material. Table 4 includes data which was
obtained from a experiment using a two-step demulsification/sorption process on
a solution containing emulsified chlorpyrifos. It can be seen that significant
reduction in chlorpyrifos concentration was achieved by first demulsifying
(calcium hydroxide) and sorbing (steam-exploded wood) (first step), followed by
additional exposure of the solution to one of three sorbents tested (second
step). Although activated carbon did not remove as much chlorpyrifos as did two
types of steam-exploded wood, the level was less than that found resulting from
a one-step (24 hours of mixing) treatment.
We are in the process of applying the information which we have obtained
to field studies. We have constructed a prototype which is designed to cleanup
30 to 40 gallons of pesticide-laden rinsate in a one-step process. Difficulties
have been encountered in developing a suitable filtration system associated with
the apparatus. We have found that to achieve good wastewater cleanup when using
finely ground lignocellulosic sorbents, removal of these particulates by
filtration is essential because pesticides sorbed to these particles remain
suspended in solution as a part of the particulate phase. Filters have been
found to be too porous to achieve good cleanup, or they become clogged with
particulates, resulting in unacceptably slow filtration rates. Because
laboratory findings suggest that a two-step process is more effective in
wastewater cleanup, we are redesigning the prototype unit to field test this
hypothesis.
37
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Table 3. Removal of Pesticides From a Two Component Pesticide Mixture in One
Step Using Demulslfication, Sorption. and Filtration.
Treatment Captan Azinphos-methvl
mg/kg % of initial mg/kq % of initial
concentration concentration
Initial
Control ,
no Ca(OH)2
Control
Activated Carbon,
with Ca(OH)2
Peat Moss
Wood Fibers
7764 ± 1860
983 ± 717
0 ± 0
0.7 ± 1.2
0 ± 0
0.7 ± 1.2
100
13
0.00
0.00
0.00
0.00
8377 ± 976
1000 ± 576
46 ± 22
10 ± 17
12 ± 21
12 ± 21
100
11.9
0.5
0.12
0.14
0.14
Azinophos-methal as Guthion* 35% VP and captan as a 49% WP in 100 ml were mixed with 2.5 grams sorbent and
1 gram calcium hydroxide for 4 hours. The solution was allowed to settle (30 min) and filtered using a PVC
column. Means and standard erros based on 3 replicates.
Table 4. Removal of Chlorpyrifos1 from Aqueous Solutions Using Two Steps:
Demulslfication and Sorption, and Column Sorption and Filtration
Treatment Concentration % of initial
(mg/kg) concentration
Initial 4866 ± 146 100
4 hour mix, no filtration
(first step) 2841 ± 152 56
24 hour mix + filtration2
(first step only) 116 ± 38 2.4
Activated carbon
(second step)
Wood fiber (second step)
Bleached wood fiber
(second step)
72 ±
7 ±
1 ±
2
2
0
1.5
0.13
0.013
Chlorpyrifos as Oursban" 4E (44.4% ai) at approximately 5000 mg/kg (1500ml) was mixed with 37.5 grams of
steam-exploded wood fiber and 15 grams calcium hydroxide for 4 hours. After mixing, 100 ml was filtered
2 through 2.5 grams sorbent contained in glass columns. Means and standard errors based on 3 replicates.
Data from a previous experiment (Table 2) using one step demulsification/sorption and filtration was included
here for comparison.
38
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Disposal Phase
Studies on chemical and biological degradation of pesticides in bioreactors
using solid substrate fermentation have been conducted at several levels. A
benchtop composting system has been employed to examine the rate and metabolic
fate of chlordane and diazinon using radiolabeled materials (Petruska, et al.
1985). Field studies using large (6.7 cu ft) bioreactors have been used to
demonstrate efficacy of biodegradation of diazinon, chlorpyrifos, metolachlor,
atrazine, carbofuran and chlordane (Mull ins, et al., 1989; Hetzel, et al., 1989).
Some compounds are degraded quite rapidly in bioreactors containing peat moss
that is enriched with corn meal. High levels of Diazinon AG500 (7.4 liters; at
an estimated 66,000 mg/kg) were not detectable one year after the last addition
of diazinon (Hetzel, et al., 1989). Recent studies using ten gallon bioreactors
to examine degradation of carbofuran and atrazine using enrichment microbial
culture have provided some interesting results (Berry, et al., unpublished data)
Carbofuran sorbed onto peat moss (1771 ± 29 mg/kg) and mixed with corn meal
(10:1) was degraded to 7 ± 3 mg/kg (0.4% of the initial concentration) in days.
One metabolite, carbofuran phenol increased in concentration from 0 (initial) to
198 ± 108 mg/kg (35 days) to 0 (50 days) indicating that degradation of
carbofuran metabolites may continue towards complete mineralization. Solid
substrate fermentation of atrazine-laden lignocellulosic materials (1455 ± 11
mg/kg) in 10 gallon bioreactors resulted in a concentration reduction to 117
mg/kg (8% of the initial concentration) in 104 days. The concentration of a
metabolite hydroxyatrazine reached 232 ± 82 mg/kg, and decreased to non-
detectable levels at 104 days. This also demonstrates the potential obliteration
of pesticide metabolites contained in composting environments (Berry, et al.,
unpublished data).
CONCLUSIONS AND FUTURE NEEDS
The pesticide wastewater disposal strategy using sorption and
biodegradation as a potential method for pesticide applicators is supported by
the information presented. We have demonstrated that one-step demulsification,
sorption and filtration provides effective removal of pesticides having low water
solubilities. The pesticides tested represented several types of pesticides and
formulations. Aqueous solutions containing two pesticides also were reduced to
low concentration levels by the one-step process. An experiment with
chlorpyrifos using a two-step demulsification-sorption, and sorption-filtration
process indicates effective wastewater cleanup can be achieved in this manner.
Comparison of results obtained using this method with other reports is
encouraging. Dennis and Kolbyinsky (1983) were able to remove 7 pesticides (100
mg/kg, totaling 700 mg/kg) contained in 400 gallons using 45 Ibs of Calgon F-300R
activated carbon in a Carbolator. After a 21 hour treatment, concentrations
ranged from 0.5 to 5.6 mg/kg. Somich, et al. found that treatment of a mixture
of 4 pesticides (ranging from 17 to 82 mg/kg using ozone and biologically active
soil columns, 1 to 20% of the pesticides remained. It should be noted that in
our experiments, much higher initial concentrations (approximately 5000 mg/kQ)
have been used resulting in removal of significant quantities of the pesticides
from the aqueous phase.
39
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The advantages of the system under development includes its relative
simplicity, reliance on low cost materials, safety, and potential for using
microbial enrichment cultures for other purposes. It is likely that our batch
demulsification, sorption and filtration system can be replaced by column
demulsification, sorption and filtration system that will be less cumbersome to
the operator. The use of lignocellulosic sorbents in the system show good
promise because of their low cost and potential availability. Peat moss is
currently quite readily available at low cost ($0.05/lb). Steam-exploded
lignocellulosic materials represent a new source of sorbent materials that have
shown good potential in our experiments. Virtually any lignocellulosic material
(wood products, crop residues, recycled newsprint/paper) can be steam-exploded.
Cost estimates of bulk crude or unprocessed steam-exploded wood are in the range
of ($0.07/lb) which would make it competitive with peat moss. Additional
processing to produce specialized sorbents for the more polar (soluble)
pesticides would add to the cost, but this might not prove to be prohibitive.
Calcium hydroxide was selected as a demulsifying agent because of its
effectiveness, relatively inexpensive and available. In fact, calcium hydroxide
is marketed as burn lime, and sold as an agrichemical at many agricultural supply
stores. Cost estimates for the pesticide rinsate disposal prototype under
development range between $600 to $900.
A major advantage of a sorption disposal process is that once the rinsate
has been treated, the sorbed pesticide no longer represents a major contamination
threat, should it be spilled. It can be collected and moved to a bioreactor
quite easily. It should also be pointed out that as pesticide-degrading
enrichment cultures are developed for a variety of pesticides, it is likely that
these consortia could be used to degrade pesticides in contaminated soil. In
situ, on site bioremediation may be possible by amending soils with
lignocellulosic materials and pesticide-degrading microbes.
Several questions regarding the rinsate solution cleanup process need to
be answered. Acceptable pesticide levels contained in treated rinsates destined
for release in sewer systems, land application, etc. need to be established
before the system can be approved and implemented. If alkaline demulsification
is used, it will be necessary to neutralize the treated rinsate. Laboratory
studies have indicated that small amounts of dilute solutions (0.2N) of
hydrochloric acid can neutralize the treated rinsate. Hydrochloric acid (as
muratic acid) is commonly used to cleanup masonry and is relatively inexpensive
and available at most hardware stores. Another concern is what can be done with
spent compost material when it is removed from bioreactors? It should be noted
that during the composting process, the volume of lignocellulosic material will
be reduced by as much as 20%. Ideally, if pesticides are effectively degraded
in the bioreactors, there will be little pesticide residue remaining in the spent
matrix. If this is the case, it would appear that the material could be land
farmed or alternately, incinerated. It is also possible that spent compost could
be reused as a sorbent. Studies are planned to evaluate these and other options
which might be available for final disposal of this material.
ACKNOWLEDGEMENTS
This work was supported in part, by the Southern Region Impact Assessment
Program, Virginia Agricultural Council, and the Virginia Center for Innovative
Technology (Biobased Materials Center). Appreciation is extended to Ms. Andrea
DeArment for the technical assistance she provided during major portions of our
work.
40
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REFERENCES
Bridges, J. S. and C. R. Dempsey, Eds. 1988. Pesticide Waste Disposal
Technology. Park Ridge, N. J. Noyes Data Corporation.
Dennis, W. H. and E. A. Kobylinski. 1983. Pesticide-laden Wastewater Treatment
for Small Waste Generators. J. Environ. Sci. & Health 18:317-331.
Hart, S. A. 1991. Composting Potentials for Hazardous Waste Management. In
Biological Processes, Innovative Hazardous Waste Treatment Series, Vol. 3, F. R.
Sfrerra, Ed. Technomic Publishing Co. Lancaster, Pa.
Hartley, D. and H. Kidd, Eds. 1987. The Agrichemicals Handbook. 2nd edition.
Royal Soc. Chem., The University of Nottingham, England.
Hetzel, G. H., D. E. Mull ins, R. W. Young and J. M. Simonds. 1989. Disposal of
Dilute and Concentrated Agricultural Pesticides Using Absorption and Chemical and
Microbial Degradation. In: Pesticides in Terrestrial and Aquatic Environments.
Proc. Nat. Res. Conf. Richmond, Va. D. L. Weighman, Ed. pp 239-248.
Judge, D. N., D. E. Mull ins, G. H. Hetzel and R. W. Young. 1990. Studies On
Demulsification and Sorption of Several Pesticides onto Lignocellulosic
Substrates Using Fluorometric and Gas Chromatographic Techniques. In:
Pesticides in the Next Decade: The Challenges Ahead. Proc. 3rd Nat. Res. Conf.
on Pesticides. Richmond, Va. D. L. Weighman, Ed. p 145-158.
MacCarthy, P. and K. E. Djebbar. 1986. Removal of Paraquat, Diquat and Amitrol
From Aqueous Solution by Chemically Modified Peat. J. Environ. Qual. 15:103-107.
Mull ins, D. E. R. W. Young, C. P. Palmer, R. L. Hamilton and P. C. Sherertz.
1989. Disposal of Concentrated Solutions of Diazinon Using Organic Absorption
and Chemical and Microbial Degradation. Pestic. Sci. 25:241-254.
Myrik, C. 1990. AgriChemical Dealership Site Assessment and Remediation. Proc.
Infer. Exchgn. Meet., Memphis, TN. Nat. AgriChem. Retail. Assn. Norwood, V. M.
1990. A Literature Review of Waste Treatment Technologies Which May Be
Applicable to Wastes Generated at Fertilizer/Agrichemical Dealer Sites.
Tennessee Valley Authority Bulletin Y-214.
Overend, R. P. and E. Chornet, 1987. Fractionation of Lignocellulosics by
Steam-aqueous Pretreatments. Phil. Trans. R. Soc. Lond. A. 321:523-536.
Petruska, J. A., D. E. Mull ins, R. W. Young and E. R. Collins. 1985. A Benchtop
System for Evaluation of Pesticide Disposal by Composting. Nuclear and Chem.
Waste Manag. 5:177-182.
Parr, J. F., E. Epstein and G. B. Willson. 1978. Composting Sewage Sludge for
Land Application. Agri. Environm. 4:123-137.
Seaman, D. 1990. Trends in the Formulation of Pesticides—An Overview. Pestic.
Sci. 29:437-449.
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Somich, C. J., M. T. Muldoon, and P. C. Kearney. 1990. On-site Treatment of
Pesticide Waste and Rinsate Using Ozone and Biologically Active Soil. Environ.
Sci Technol. 24:745-749.
Thomas, B. 1990. Regulatory pressures on pesticide formulations. Pestic. Sci.
29:475-479.
Walls, R. R. 1981. Analytical Reference Standards and Supplemental Data for
Pesticides and Other Organic Compounds/ USEPA-600-12-81-001.
Ware, 6. 1989. The Pesticide Book. Thomson Publications, Fresno, Ca. 3rd Ed.
340pp.
Williams, R. T. and C. A. Myler, 1990. Bioremediation Using Composting.
BioCycle. 31:78-82.
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LEGENDS FOR FIGURES
Figure 1. Conceptual/Functional Model for Pesticide Wastewater Disposal
using Organic Sorption and Microbial Degradation.
The process involves two phases: a sorption phase, and a
disposal phase.
The sorbent phase involves mixing pesticide-laden waste
solutions (or suspensions) with organic sorbents
(lignocellulosic materials such as peat moss, processed wood
products, etc.). During this phase, pesticides are removed
from the aqueous solution by demulsification and sorption
processes.
The disposal phase begins with the separation of the sorbed
pesticide from the treated aqueous solution by filtration.
The aqueous solution may then be discarded and the pesticide-
laden sorbent added to bioreactors. Microbial populations
native to the matrix will degrade the pesticide.
Figure 2. Pesticide Biodegradation Using Nutrient Enrichment and
Microbial Consortia.
A hypothetical representation of pesticide microbial
degradation in a situation where an organic matrix and
nutrients are available to microbial populations. As the
bioreactor cycles from higher to lower energy content,
microbial populations will also cycle reflecting the changes
in substrate availability. Pesticides which are more
resilient to microbial degradation will require longer
reaction times.
43
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VASTE:
Pesticide-laden
Vaste Solution
DEHULSIFICATION &
SORPTION:
Lignocellulosic
Matrices
FILTRATION
DISCARD/RECYCLE:
Purified Solution
DISPOSAL:
Pesticide Degradation
Microbial Bioreactor
Figure 1. Conceptual/Functional Node! for Pesticide Wastewater
Disposal Using Organic Sorptlon and Mircrobial Degradation
44
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Nutrient
Adcftion
I
c
u
B
a
n
t>
0.
Mcrobial
Coreortiim
Changw ?
0.
E
e
5
0)
J
0)
Figure 2. Pesticide Biodegradation Using Nutrient Enrichment and
Hicrobial Consortia
45
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Landfarming and Biostimulation for Decontaminating
Herbicide Wastes In Soil
by
Kudjo Dzantor and A.S.Pel sot
Center for Economic Entomology, Illinois Natural History Survey
607 E. Peabody Drive, Champaign Illinois 61820 USA
ABSTRACT
The utility of landfarming for detoxifying pesticide waste in soil was
examined at an agrichemical facility in Piatt County, 111. Soil contaminated
with the herbicides alachlor, atrazine, metolachlor, and trifluralin was
excavated, and various amounts were applied to an adjacent field divided into
corn and soybean plots. Dissipation of residues was monitored for nearly two
years following application of the contaminated soil. Data from soiltreated
subplots were compared to data from subplots in which herbicides were freshly
sprayed. Herbicides did not dissipate significantly in excavated soil that had
been stockpiled on the ground. After two years, alachlor and metolachlor
concentrations in subplots with the highest application rate of contaminated soil
were significantly greater than concentrations in the corresponding freshly-
sprayed subplots. In subplots with the lowest application rate of contaminated
soil, alachlor and metolachlor persistence did not differ significantly from
persistence in plots freshly-sprayed with recommended application rates.
In the laboratory, soil amendment with 2% w/w ground corn or soybean
residues or sewage sludge enhanced the degradation of 100 ppm alachlor compared
to the degradation in unamended controls. Soil amendment with the crop residues
at the rate of 10% w/w did not significantly increase the rate of alachlor
degradation over that observed at the 2% level of amendment, however 10% sewage
sludge significantly accelerated alachlor degradation when compared to the 2%
amendment. Addition of 1000 ppm inorganic N in the form of NH4N03 significantly
inhibited alachlor degradation in both unamended and crop residueamended soils
compared to the degradation in soils without N or with 10 ppm N.
In two soil types alachlor disappeared fastest in water-saturated soils
that were left unamended or amended with 2% w/w ground corn residue. Under the
saturated conditions, alachlor was transformed into an unidentified nitrogen-
containing product that was not detected under unsaturated conditions.
Soil inoculation with an alachlor-cometabolizing fungus produced a
transient and marginal increase in alachlor degradation rate over the degradation
rate in uninoculated soils. Combinations of 2% w/w corn residue amendment and
fungal inoculation did not increase alachlor degradation over that caused by corn
amendment alone.
INTRODUCTION
There is increasing recognition that soils at many agrichemical facilities
and farms have been contaminated with high concentrations of pesticides through
accidental spills or improper rinsing and discharge procedures (Long, 1989).
High concentrations of ordinarily biodegradable pesticides can be extremely
persistent in soil partly because they inhibit soil bioactivity (Wolfe et
46
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al.,1973, Staiff et al.,1975, Davidson et al.,1980, Winterlin et al.,1989, Felsot
and Dzantor 1990a, Dzantor and Felsot 1991). High concentrations of many
pesticides are more mobile than low concentrations (Davidson et al.,1980). The
combination of prolonged persistence and greater mobility increases the risk of
surface and groundwater contamination by high pesticide concentrations and
emphasizes the need for their expeditious cleanup.
The usual methods of disposing of waste contaminated soils are excavation
and subsequent landfill ing or incineration. These methods are expensive in
economic and environmental terms, yet they do not always address the problem of
contaminant detoxification. As more contaminated sites are discovered, it is
becoming increasingly important to seek cleanup technologies that are permanent
and duly cognizant of the widespread nature of the waste problem. More permanent
solutions could involve decontamination by landfarming (also known as land
application or land treatment), biological treatment (bioremediation), or
combinations thereof.
Typical problems faced by agrichemical facilities were demonstrated at the
Galesville Chemical Co. (GCC) in Piatt County, 111. (Felsot et al. 1988). Soil
to a depth of 1m along a railroad-right-of-way at the GCC facility had been found
by the Illinois EPA (IEPA) to be contaminated with unacceptably high levels of
herbicides (e.g. 24,000 ppm alachlor in the top 10 cm, 100 ppm at a depth of 60
cm). The herbicides were discharged to this area as a waste stream arising from
the mixing, loading, and cleaning operations of GCC. Pesticide residues were
detected in the ditches lining the streets of Galesville (population <500), and
trace levels were detected in two water wells. IEPA ordered excavation and
clean-up of the site.
To avoid obtaining a special waste permit and hauling contaminated soil to
a municipal landfill, the Illinois Natural History Survey collaborated with IEPA
and the management of GCC to landfarm the contaminated soil in corn and soybean
plots on an adjacent farm. The soils were excavated and stored on the ground in
piles, which were sampled to determine residue levels and microbial activity.
After application of contaminated soil to soybean and corn plots, herbicide
residues were monitored in the soil for nearly two years. Along with the
landfarming studies, laboratory experiments were performed to identify factors
that influence the degradation of alachlor, the prevalent chemical at the
contaminated site, and determine how they may be manipulated to maximize
degradation of the herbicide. We wish to present our observations on the
dissipation of herbicides after landfarming of contaminated soils. In laboratory
studies, we also show how degradation of alachlor is affected by nutrient
amendment, soil moisture content ,and microbial inoculation.
METHODOLOGY
Landfarminq Experiment
Site Description--
GCC drained waste water from loading and tank rinsing operations onto a
railroad right-of-way along the eastern edge of its property. Soil in this area,
which covered approximately 1,215 m2, was excavated and stored on the ground at
the site in four piles designated as "waste pile soil" 1-4.
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After excavation, the site was backfilled with soil from an adjacent fence
row that was at a higher elevation and presumed not to be contaminated from the
waste-water discharges. Waste-pile soil 2, which contained the highest levels
of herbicides, was excavated from the top 60 cm of an area encompassing 122 m2
and was used in subsequent land application experiments. Contaminants included
alachlor, atrazine, metolachlor, and trifluralin.
During the spring of 1986, a four-acre field adjacent to the railroad
right-of-way and to the north of the waste piles was divided into two, 2-acre
fields for land application of waste-pile soil 2. The field had been planted to
corn in 1985 and chisel plowed in the fall. In 1986, the southern half of the
field was designated for corn production and the northern half was designated for
soybeans. The soil was a mixture of Ipava silt loam and a Sable silty clay loam
with an organic carbon content of 3.1 percent and moisture content of 22.6
percent w/w at 0.3 bar. Waste-pile soil had an organic carbon content of 5.6
percent and a moisture content of 30.3 percent w/w at 0.3 bar.
The corn and soybean plots were further subdivided into three replicated
blocks containing six subplots, (12.3m x 12.3m or 40 ft x 40 ft), that were
treated with contaminated soil or freshly sprayed with herbicides (see below for
details of the treatments). Each plot was surrounded by a 6.2m x 6.2m untreated
buffer zone. Corn and soybeans were planted within one week of soil and spray
applications. Each plot contained 16 crop rows spaced 76 cm apart.
After the crop was harvested in 1986, the plots were left untilled, and
benchmarks placed so that plots could be re-established in the same positions
during the 1987 crop year. In May, the field was treated with paraquat to burn
down perennial weeds. On June 10, 1987, the field was prepared by chisel plowing
in a north-south direction, parallel to the old crop rows. Untreated border
areas around each plot prevented soil from one subplot from contaminating an
adjacent subplot. Corn and soybeans were planted along the north-south direction
on the same day. No further applications of soil or herbicides were made.
Application of waste-contaminated soil--
Persistence of herbicides in landfarmed, contaminated soil was compared to
persistence of herbicides that were freshly sprayed with amounts calculated to
yield concentrations in soil similar to those in waste-pile soil 2. Rates of
application were determined on the basis of the alachlor concentration since it
was the most prevalent contaminant. Treatments were designated by the following
codes:
1. CHECK: untreated soil;
2. Ix-N: herbicide spray mixture applied in 1986 at the rate normally
recommended for alachlor, 3.36 kg active ingredient [a.i]./ha; the mixture
consisted of alachlor, atrazine, metolachlor, and trifluralin in
proportion to the concentrations found in waste-pile soil 2 in May, 1986
(74, 48, 17, and 3 mg herbicide/kg oven-dry soil [ods], respectively,
Pel sot et al. 1988);
3. 5x-N: herbicide spray mixture applied in 1986 at 18.6 kg a.i./ha, five
times the recommended alachlor rate;
4. Ix-S: contaminated soil from waste-pile 2 applied at the equivalent
alachlor rate of 3.36 kg a.i./ha;
5. 2.5x-S: waste-pile soil applied at the equivalent alachlor rate of 8.4 kg
a.i./ha;
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6. 5x-S: waste-pile soil applied at the equivalent alachlor rate of 18.6 kg
a.i./ha.
Soil was applied with a manure spreader. The spreader was filled by using
a front loader that was calibrated by weighing the entire loader with and without
a full load of soil. Within 24 hours after application of contaminated soil and
herbicide sprays, all plots were disked twice in two directions to incorporate
the pesticides and soil. Buffer zones were also disked, which served to clean
equipment and minimize cross-contamination between treatment plots.
Soil sampling, preparation, storage--
Soils were collected from field plots with a 5-cm diam. bucket auger during
1987 and early 1988. Two subsamples of soil from depths 0-15 cm and 15-30 cm
were collected from each replicated subplot. The subsamples were combined in the
field and returned to the laboratory on the same day. The auger was washed with
methanol between subsamples taken by soil depth and between different subplots.
Soils were sieved through a 3mm mesh screen and stored at 2i C for up to one
month prior to extraction. Herbicide residues remained stable under these
conditions for at least four months (Felsot et al. 1988).
Extraction and Analysis--
Fifty grams of soil were slurried with 20 ml of distilled water and
extracted twice with 90 mL of ethyl acetate as described by Dzantor and Felsot
(1989) for methyl carbamate insecticides. All herbicides were qualitatively
analyzed by packed column gas-liquid chromatography (GLC, Packard Model 328) with
nitrogen-phosphorus specific detection. Residues were separated isothermally at
190 fC on a 90 cm x 0.2 mm i.d. glass column packed with 5% Apiezon + 0.1% DEGS.
Residues were quantified by the method of external standards, which were used to
calibrate the GLC response each day of analysis.
Biostimulation and Bioauqmentation Experiments
Soil Incubation--
The soil used in most of the experiments was collected from untreated
experimental plots at the Galesville landfarming site. Freshly collected soil
was air dried to about 20% moisture content, passed through a 2mm sieve, and
stored a 5iC until needed. All experiments were performed in triplicate with
30 g ods in 250 mL erlenmeyer flasks. An emulsifiable concentrate of alachlor
(Lasso, 4EC; 45.1% a.i) was added as a dilution in water to give 100 mg ai/kg in
soil. After treatment, soils in individual flasks were brought to desired
moisture tensions by additions of distilled water. The flasks were covered with
parafilm and the soils were incubated at 25iC for specified periods of time.
The soils were aerated once a week. At the start of each experiment and at
specified intervals during the incubation period, three flasks from each
treatment were frozen (-10f C) for chemical assay. Soil in three flasks from
each treatment were slurried with 15 mL of water and extracted twice by stirring
with 90 mL of ethyl acetate. Parent alachlor was determined by packed column
gas-liquid chromatography as described above.
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Effect of nutrient amendments on alachlor degradation--
To determine the effect of organic amendments on alachlor degradation, bulk
soil samples were weighed into large plastic bags and mixed thoroughly with
either corn plant residue, soybean plant residue or municipal sewage sludge at
the rate of 20 or lOOg/kg ods (2 or 10% w/w) before distribution into flasks.
The amendments had been ground to pass a 2 mm sieve. Soils without organic
amendment served as controls.
To examine the effect of inorganic nitrogen on alachlor degradation, soils
were amended with NH4N03 to yield 10 or 1000 mg N/kg ods. Soils without NH4N03
served as controls. Combinations of the crop residue amendments and inorganic
N were also tested.
Effect of fungal inoculation on alachlor degradation--
To examine the effect of microbial inoculum on alachlor degradation, soils
were inoculated with an alachlor-cometabolizing Fusarium sp. (Felsot and Dzantor
1990a). The inoculum was grown in a peptone-yeast extract-alachlor (lOOppm
alachlor) medium on a rotary shaker at 25i C. After three days, growth was
harvested by centrifugation at 13,000 rpm (25931 x g) for 10 mins. The cells
were washed once and resuspended in autoclave-sterilized phosphate buffer
containing lOOppm alachlor. Washed cells were stored at 2i C until needed.
Soils were inoculated within 24h of harvest and within one to two hours after
addition of alachlor.
RESULTS AND DISCUSSION
Landfarming Study
During the planning of the landfarming experiment, we developed four
criteria for successful remediation of the herbicide-contaminated soils: (1) no
significant difference after one growing season between herbicide residues in
soil from waste-treated plots and freshly sprayed plots; (2) no contamination of
shallow groundwater above maximum contaminant levels (MCLs) suggested by U.S.
EPA; (3) no significant residues in grain; (4) no significant toxicity to crops
as measured by phytotoxicity assays in the field or greenhouse and by comparison
to yields from the untreated check plots. The extent to which criteria 2-4 were
met has been presented elsewhere (Felsot and Dzantor 1991), so this discussion
will be limited to herbicide dissipation during landfarming.
Herbicide residues in soil--
Soil samples collected within a day after application of waste-pile soil
and herbicide sprays afforded a comparison of the initial concentration of
herbicides found in all experimental plots compared to the theoretical amounts
corresponding to the various rates of application. On the basis of a 3.36 kg
a.i./ha application rate (i.e.., Ix treatment), the soil to a depth of 15 cm
should have contained theoretically 1.71, 4.28, and 8.55 ppm of alachlor for a
Ix, 2.5x, and 5x application rate, respectively. The percentage of theoretical
recovery ranged from 33.6% for the 5x-S soybean treatment to 110% for the Ix-N
corn treatment. Percentage of theoretical recovery for all treatments combined
was 66.5+/-23.0%.
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Another concern was the initial concentrations of herbicides in soiltreated
plots compared to the corresponding treatments in sprayed plots. With the
exception of the 5x-S and 5x-N alachlor treatments in the soybean plots, there
were no significant differences in recovery of herbicides between soil-applied
and sprayed herbicide on day 0 in the top 15 cm of the profiles (Fig. 1, 2).
Nearly twice as much alachlor was recovered from the 5x-N treatment in the
soybean plot as from the 5x-S treatment. This difference may reflect sampling
error because concentrations of alachlor recovered later from the 5x-S treatment
were much higher than the initial recoveries (Fig. 1).
During the first 140 days of sampling, high variability precluded the
detection of significant differences between corresponding rates of application
of fresh herbicide and contaminated soil. By days 380 and 520, however,
significantly more alachlor and metolachlor were recovered from 5x-S treatments
than from 5x-N treatments (Fig. 1, 2). No statistically significant differences
were seen between Ix-N and Ix-S or 2.5x-S treatments, although the latter two
were often numerically greater than the Ix-N treatment (data not shown).
Recovery of the other herbicides did not differ significantly among treatments
on these sampling days. Residues at the 15-30 cm depth did not differ among
treatments.
The three-to-10 fold greater recoveries of alachlor and metolachlor from
the 5x-S treatment than from the 5x-N treatment suggested that the residues in
the aged, contaminated soil were less available to microbial degradation. The
residues recovered 1.5 years after application were more than half of what would
be expected after a recommended application rate of 3.36 kg ai/ha. The prolonged
persistence of alachlor and metolachlor in waste-pile soil and in the field plots
is not characteristic of the comparatively rapid degradation of these compounds
when used at normal rates of application. Alachlor half-life generally ranges
from 2-4 weeks (Sharp 1988), and it is less persistent than metolachlor, whose
half-life is highly variable (13-108 days) depending on moisture and temperature
conditions (LeBaron et al. 1988). On the other hand, several studies have shown
that high concentrations of pesticides, which are characteristic of waste, are
unusually persistent (Davidson et al. 1980, Stojanovic 1972, Junk et al. 1984,
Schoen and Winter!in 1987, Wolfe et al. 1973). In our study, alachlor and
metolachlor were still found in waste-pile 2 at concentrations of 23 and 17ppm,
respectively, two years following excavation.
Two hypotheses were developed to explain the prolonged persistence of
alachlor and metolachlor in the waste-pile soils and in the field plots. First,
studies of high concentrations of pesticides in soil have shown that microbial
populations can be severely reduced, which may be the critical factor for
explaining the prolonged persistence of those chemicals (Stojanovich 1972,
Davidson et al. 1980, Dzantor and Felsot 1991). We therefore hypothesized that
the microbial populations in the waste-pile soils were reduced as a result of
exposure to toxic concentrations of the herbicides.
The inhibition of microbial populations, however does not explain
adequately the prolonged persistence of the herbicides after mixing waste-pile
soil with uncontaminated soil during land application. The herbicides in waste-
pile soil could be considered to be aged (Smith et al. 1988), i.e., the chemicals
were in contact with the soil for an extended period of time. Aged residues have
been shown to be less desorbable (McCall and Agin 1985, Steinberg et al. 1988)
and in some cases seem to degrade more slowly than freshly-applied chemicals
(Steinberg et al. 1988, Byast and Hance 1981). Thus, a second hypotheses, but
51
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not mutually exclusive of the first, ascribes the slow degradation of the
herbicides to a lack of pesticide bioavailability upon aging in the soil.
Biostimulation Study
The prolonged persistence of alachlor after contaminated soil had been
spread on cropland suggested that landfarming alone may not be sufficient for
remediating all contaminated soils regardless of contaminant composition,
concentration, or age. We previously reported that amending soils in the
laboratory with 2% corn or soybean residues enhanced the degradation of 100 ppm
but not 1000 ppm of freshly applied alachlor (Pelsot and Dzantor 1990a). If
degradation of up to 100 ppm of herbicide can be thus accelerated in the field,
then biostimulation may be the strategy for detoxifying high concentrations of
contaminants after they have been diluted by landfarming, or for detoxifying
moderately high concentrations of pesticides in situ. Successful application of
this strategy depends on the understanding of the soil environmental factors that
control degradative processes. In our continuing efforts to stimulate the
degradation of alachlor in soil, we have further investigated the effects of
types and levels of nutrient amendments, soil moisture content, combinations of
moisture and nutrient amendments, and bioaugmentation with fungal inoculation.
Effect of nutrient amendments on alachlor degradation--
Similar to our previous observations, 100 ppm of alachlor degraded more
rapidly in corn or soybean residue-amended (2% w/w) soils than in unamended soil
(Fig. 3,4). Soil amendment with 10% of either type of crop residue produced only
marginal increases in alachlor degradation over that observed with 2% amendment.
In a more recent experiment we observed that alachlor degraded at similar rates
in soils that were amended with either 2% corn residue or 2% municipal sewage
sludge. But unlike corn residues, soil amendment with 10% sewage sludge caused
a significant enhancement in alachlor degradation over that observed at the 2%
level of amendment (Fig. 5). Within 28 days, <12% of the initial lOOppm dose of
alachlor was recovered in soils amended with 10% sewage sludge. In contrast,
about 40% of the initial dose was recovered in the soils amended with 2% corn
residue or sewage sludge; the unamended soil still contained approximately 70%
of the added alachlor after 28 days. Since the enhancement of the rate of
alachlor degradation did not appear to be a linear function of the level of
sewage sludge, we are now attempting to determine the minimum sewage sludge
application rate at which degradation is optimized.
In a preliminary experiment, we observed that addition of NH4N03 to soil
to give 1000 ppm N appeared to inhibit the stimulatory effect that crop residue
amendment had on the degradation of 100 ppm alachlor (Felsot and Dzantor 1990 b).
Recoveries of the herbicide in residue amended soils that were also treated with
N were not significantly different from recoveries in unamended soils. Because
we did not determine the effect of inorganic N on alachlor degradation in
unamended soil in preliminary experiments, a follow up experiment was performed
to examine the effect of different levels of inorganic N with or without crop
residue amendments on the degradation of 100 ppm alachlor.
After 56 days, alachlor recoveries were highest (>80% of initial dose) in
unamended soils that were also treated with 1000 ppm N (Fig. 6); the lowest
recoveries of the herbicide (4-5 %) were from crop residue-amended soils that
were treated with 0 or 10 ppm N. The 1000 ppm N addition reduced the stimulatory
effect of organic residue amendment, as we have had observed in preliminary
52
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studies, but alachlor dissipation was still significantly faster than in all
unamended soils (Fig. 6). Other researchers have shown that certain forms and
levels of inorganic N inhibit degradation of some pesticides. For example, the
degradation of parathion in soil was inhibited by 100 ppm N in the form of
(NH4J2S04 but not as NH4N03 (Ferris and Lichtenstein 1980). However, at 182 ppm
N equivalent, NH4N03 also significantly reduced degradation of parathion. The
inhibition of pesticide degradation by high concentrations of inorganic N may be
quite important. Operations at many agrichemical facilities and farms may
involve nitrogen fertilizers as well as pesticides; it is quite likely that soils
contaminated by pesticides at some of these sites may also be contaminated by
high levels of N fertilizers.
Effect of Soil Moisture Tension on Degradation of Alachlor--
Figures 7 and 8 show the effects of soil moisture content on the
degradation of 100 ppm of alachlor in two soil types that were either left
amended or amended with 2% ground corn residue. The second soil type, coded as
soil 52, was collected from part of an experimental field at the Illinois Natural
History Survey. It is a Drummer-Catlin mixture with an organic carbon content
of 2.0%, and moisture content of 24.7% w/w at 0.3 bar. Alachlor degradation was
investigated at soil moistures ranging from wilting coefficient (15 bar),
corresponding to 11.6 and 12.1% w/w for GCC soil and soil 52, respectively to
saturation (0 bar) or 100% w/w moisture content in both soil types.
Alachlor recovery from both soil types decreased as soil moisture content
increased (decreasing moisture tension) (Fig. 7); the combination of 2% corn
residue amendment and increasing moisture content stimulated further dissipation
of parent alachlor from both soils (Fig. 8). Several workers have demonstrated
enhanced degradation of chlorinated pesticides in anaerobic soils amended with
organic materials. For example, degradation of pentachlorophenol in flooded
soils was enhanced by addition of anaerobic sewage sludge (Mikesell and Boyd
1988), and DDT degraded significantly faster in anaerobic soils amended with 1%
w/w glucose (Parr et al 1970) or rice straw (Mitra and Raghu 1986). Also, gamma-
hexachlorocyclohexane degraded significantly faster in flooded soils with green
manuring compared to unamended soils.(Drego et al.,1990).
In this study alachlor also dissipated rapidly in unamended soil 52 under
saturated conditions (Fig. 7). But the rapid disappearance of parent alachlor
under saturated conditions may be misleading because, as we have observed in this
and other unpublished experiments, the loss of parent alachlor under these
conditions was accompanied by the appearance of an unidentified nitrogen-
containing metabolite that was not detected under non-saturating conditions.
Effective bioremediation would ideally require that transformation products be
removed as rapidly as parent compounds.
Effect of Fungal Inoculation on Alachlor Degradation--
We have previously reported that inoculation of soil with an alachlor-
cometabolizing fungus at the rate of 0.015% w/w ods caused a transient marginal
increase in the rate of degradation of 100 ppm alachlor, compared to the rate
of degradation in uninoculated controls (Felsot and Dzantor 1990a). The small
and temporary nature of the increase in degradation caused us to question the
efficiency and competitiveness of the fungus once it has been reintroduced into
the soil. In an attempt to answer this question, we examined the effect of a
higher level of fungal inoculation (0.045%) on the degradation of alachlor in
soils that were left unamended or amended with 2% corn residue.
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Figure 9 shows that within 28 days in unamended soil, significantly more
alachlor was recovered from uninoculated treatments than from inoculated ones.
During the same period, soils inoculated at the rate of 0.045% w/w showed a
slightly higher rate of alachlor loss than those inoculated at the rate of
0.015%. By day 56, alachlor recoveries from all unamended treatments were
practically identical, indicating that the stimulation in degradation rate by the
fungal inoculum had waned over time. Amending soils with 2% corn residue
completely masked the effect of fungal inoculation (Fig. 10)
CONCLUSIONS
Landfarming and biostimulation are becoming practical strategies for
detoxification of wastes in soils. The procedures involved are environmentally
more desirable than traditional "out of sight - out of mind" disposal methods
such as landfill ing. The technologies are also more readily affordable by small
scale operations than the more expensive and less accessible methods such as
incineration. However, these waste cleanup methods have certain limitations that
require careful evaluation prior to implementation. Our landfarming experiments
revealed that herbicides applied as waste soil generally degraded more slowly
than fresh applications, particularly at high loading rates. Another concern is
the potential for crop phytotoxicity when the waste soil contains a diverse
mixture of herbicides. A combination of excessively high levels of
contamination and space limitation may necessitate higher than normal loading
rates during landfarming. Prolonged persistence and the possibility of crop
phytotoxicity may restrict the use of landfarming.
The strategy of biostimulation is based on the so called principle of
microbial ubiquity (Mathewson and Grubbs 1989) which assumes that the requisite
degrader microorganisms are present at all contaminated sites and only their
appropriate stimulation is necessary to accelerate the degradation of each
contaminant. However, soils do differ in their abilities to be stimulated to
degrade individual compounds (Dzantor and Felsot 1990). Often, these differences
are related to differences in microbial profiles and accompanying specificities
to degrade different compounds. Differences in microbiological profiles also
imply that soil manipulations that may stimulate degradation of one compound may
not necessarily act on a different compound; finding the right conditions that
will accelerate degradation of pesticide mixtures may be difficult. Even if the
requisite organisms are present at a contaminated site, it may be impractical to
stimulate them to overcome toxic effects of certain chemicals if concentrations
are too high.
Our fungal inoculation experiments have demonstrated to us the difficulty
of using bioaugmentation alone to decontaminate soils. First the procedures for
obtaining individual or consortia of microorganisms to degrade specific parent
compounds and their metabolites may be tedious and time-consuming; thus, the
approach may not be amenable for contaminated sites that require immediate
cleanup. More importantly, this approach may not be feasible because of poor
competitiveness of laboratory-obtained degrader microorganisms once they have
been reintroduced into soil, as our results have suggested.
In summary, our results suggest that no one strategy alone may be
sufficient to clean up all contaminants regardless of composition, concentration
or age. The limitations have been discussed to stimulate debate rather than to
diminish the enormous potential of landfarming and bioremediation. We have yet
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to explore all the combinations of landfarming. biostimulation, or
bioaugmentation necessary to accelerate contaminant detoxification. An
understanding of the microbial ecology of biodegradation may be the key to the
successful use of these strategies to decontaminate wastes in soils.
REFERENCES
Byast, T.H., and R.J. Hance. 1981. Decomposition of linuron and simazine
incubated with soil containing aged residues. Pages 56-62 in Proc. European Weed
Research Society Symposium: Theory and Practice of the Use of Soil Applied
Herbicides.
Davidson, J.M., P.S.C. Rao, L.T. Ou, W.B. Wheeler, and D.F. Rothwell. 1980.
Adsorption, movement and biological degradation of large concentrations of
selected pesticides in soil. EPA - 600/2-80-124, 111 pp.
Dzantor, E.K., and A.S. Pel sot. 1989. Effects of conditioning,
crossconditioning, and microbial growth on development of enhanced biodegradation
of methyl carbamate insecticides in soil. J. Environ. Sci. Hlth. 824:569-597.
Dzantor, E.K. and A.S. Felsot. 1990. Soil differences in the biodegradation of
carbofuran and trimethacarb following pretreatment with these insecticides.
Bull. Environ. Contain. Toxicol. 45:531-537.
Dzantor, E.K., and A.S. Felsot. 1991. Microbial responses to large
concentrations of herbicides in soil. Environ. Toxicol. Chem. 10:649-655.
Felsot, A.S., R. Liebl, and T. Bicki. 1988. Feasibility of land application of
soils contaminated with pesticide waste as a remediation practice. Final Project
Report (HWRIC RR 021). 111. Hazardous Waste Research and Information Center,
Illinois State Water Survey Division, Savoy, IL, 55 pp.
Felsot, A.S., and E.K. Dzantor. 1990. Enhancing biodegradation for
detoxification of herbicide waste in soil. Pages 192-213 in K.D. Racke and J.R.
Coats, editors. Enhanced biodegradation of pesticides in the environment,
American Chemical Society Symposium Series No. 426, Am. Chem. Soc., Washington,
D.C.
Felsot, A.S., E.K. Dzantor. 1990 b. Enhancing the biodegradation of high
concentrations of acetanilide herbicides. Abstract 07B-24, poster presentation,
7th International Congress of Pesticide Chemistry, Hamburg, FR6.
Felsot, A.S., and E.K. Dzantor. 1991. Remediation of herbicide wastes in soil:
experiences with landfarming and biostimulation. Pages 532-551 in Pesticides
in the Next Decade: The challenges ahead. Weigmann, D.L. ed. Third National
Pesticide Conference. Virginia Polytechnic Inst., Blacksburg, VA.
Ferris, I.G., and E.P. lichtenstein. 1980. Interaction between agricultural
chemicals and soil microflora and their effects on the degradation of [14C]
parathion in a cranberry soil. Journal of Agricultural and Food Chem.
28:2011-1019.
55
-------
Junk, G.A., J.J. Richard, and P.A. Dahm. 1984. Degradation of pesticides in
controlled water-soil systems. Pages 37-67 In R.F. Krueger and J.N. Seiber,
editors. Treatment and disposal of pesticide wastes. American Chemical Society
Symposium Series No. 259, Am. Chem. Soc., Wash. D.C.
LeBaron, H.M., J.E. McFarland, B.J. Simoneaux, and E. Ebert. 1988. Metolachlor.
Pages 336-382 in P.C. Kearney and D.D. Kaufman, editors. Herbicides: chemistry,
degradation and mode of action, 3rd ed. Marcel Dekker, Inc., New York.
Long, T. 1989. Groundwater contamination in the vicinity of agrichemical mixing
and loading facilities. Pages 139-149 in Proceedings Illinois Agricultural
Pesticides Conference '89. Cooperative Extension Service, University of
Illinois, Urbana, IL.
Mathewson, J.R., and R.B. Grubbs. 1989. Commercial microorganisms. HazmatWorld
2:48-51.
McCall, P.J., and G.L. Agin. 1985. Desorption kinetics of picloram as affected
by residence time in the soil. Environ. Toxicol. Chem. 4:37-44.
Mikesell, M.D., and S.A. Boyd. 1988. Enhancement of pentachlorphenol
degradation in soil through induced anaerobiosis and bioaugmentation with
anaerobic sewage sludge. Environ. Sci. Techno!. 22:1411-1414.
Mitra, L., and K. Raghu. 1986. Rice straw amendment and the degradation of DDT
in soils. Toxicol. Environ. Chem. 11:171-191.
Parr, J.F. , G.H. Willis and S. Smith. 1970. Soil anaerobiosis: Effect of
selected environments and energy sources on the degradation of DDT. Soil Science
110:306-312.
Schoen, S.R., and W.L. Winter!in. 1987. The effects of various soil factors and
amendments on the degradation of pesticide mixtures. J.Environ. Sci. Hlth.
822:347-377.
Sharp, D.B. 1988. Alachlor. Pages 301-333 in P.C. Kearney and D.D. Kaufman,
editors. Herbicides: chemistry, degradation and mode of action, 3rd ed., Marcel
Dekker, Inc., New York.
Smith, A.E., J.A. Aubin, and D.A. Derksen. 1988. Loss of trifluralin from clay
and loam soils containing aged and freshly applied residues. Bull. Environ.
Contam. Toxicol. 41:569-573.
Staiff, D.C., S.W. Comer, J.F. Armstrong, and H.R. Wolfe. 1975. Persistence of
azinphosmethyl in soil. Bull. Environ. Contam. Toxicol. 13:362-368.
Steinberg, S.M., J.J. Pignatello, and B.L. Sawhney. 1987. Persistence of
l,2dibromoethane in soils: entrapment in intraparticle micropores. Environ.
Sci. Technol. 21:1201-1208.
Stojanovich, B.J., M.V. Kennedy and F.L. Shuman, Jr. 1972. Edaphic aspects of
the disposal of unused pesticides, pesticide wastes and pesticide containers.
J. Environ. Qual. 1:54-62.
56
-------
Winterlin,W., J. N. Seiber, A. Craigmill, T. Baier, J. Woodrow, and G. Walker.
1989. Degradation of pesticide waste taken from a highly contaminated soil
evaporation pit in California. Arch. Environ. Contam. Toxicol. 18:734-747.
Wolfe, H.R., D.C. Staiff, J.F. Armstrong and S.W. Comer. 1973. Persistence of
parathion in soil. Bull. Environ. Contam. Toxicol. 10:1-9.
57
-------
freshly spraye*
•soil treated — A— untreated
8OO
0 100 2OO 30Q 400 SQO
10O 200 300
0 500 600
Days After Application
Figure 1. Alachlar residues In corn and soybean plots
treated with fresh herbicide sprays or with
herbicide-contaminated soil at the equivalent
rate of 16.8 kg a.i./ha.
58
-------
freshly spraye<
10
•soil treated — A— untreated
as
I
I
i
o.oi
0 1OO 2OO 30O 400 500 BOO
10O 80O 000 400 600 GOO
Days After Applicatio:
Figure 2. Metolachlor residues in corn and soybean plots
treated with fresh herbicide sprays or with
herbicide-contaminated soil set the equivalent
rate of 2.85 kg aui./ha.
59
-------
Figure 3. Effect of Corn Residue Amendment on
Degradation of 100 ppm Alachlor in GCC Soil
s
Corn Residue
none
2%
10 »
10 20 30 40 SO 60
Days after Treatmen
-------
19
% of Initial Recovered
10
o
G)
O
GO
O
O
o
O 4-
-------
Figure 5. Effect of Type and Level of Amendment on
Degradation of 100 ppm Alachlor in GCC Soil
cr>
ro
Amendment
None
Corn Res.
2% Sew. Slg
10% Sew. Slg
Days
-------
CJ
Figure 6. Effect of Inorganic N on Degradation
of 100 ppm Alachlor in GCC Soil
-0
B
U
U
100
Inorganic PI
0 None
M 10 ppm
• 1000 ppm
None 2% corn 2% soybean
Organic Amendment
-------
Figure 7, Effect of Moisture Tension on Degradati*
of 100 ppm Alachlor in 2 Soil Type
100
Soil GCC Son 52
Soil Type
Moistuit
Tension
U 15 bat
i 0.3 bar
• Obai
-------
o>
en
Figure 8. Effect of Moisture Tension on Degradation
of 100 ppm Alachlor in 2 Soil Types
_ 100
T3
E.eoj
60
•a 40
o
20
«
Amended
SoilGCC
Soil 52
Soil Type
Moisture
Tension
15 bat
0.3 bar
Obar
-------
99
% of Initial Recovered
10
o
en
o
o
o
-------
0>
Figure 10. Effect of Fungal Inoculation on Degradation
of 100 ppm Alachlor in GCC Soil
100
0
Amended
Inoculation
None
0.015%
0.045%
-------
Removal of Pesticides From Aqueous Solutions
Using Liquid Membrane Emulsions
by
Dr. Verrill M. Norwood, III
Chemical Research Department
Tennessee Valley Authority
National Fertilizer and Environmental Research Center
Muscle Shoals, Alabama 35660-1010
ABSTRACT
Extractive liquid membrane technology is based on a water-in-oil emulsion
as the vehicle to effect separation. An aqueous internal reagent phase is
emulsified into an organic phase containing a surfactant and optional complexing
agents. The emulsion, presenting a large membrane surface area, is then
dispersed in an aqueous continuous phase containing the species to be removed.
The desired species is transferred from the continuous phase through the organic
liquid membrane and concentrated in the internal reagent phase. Extraction and
stripping occur simultaneously rather than sequentially as in conventional
solvent extraction.
Liquid membranes have been used to extract phenol, acetic acid, other
weakly ionized acids and bases, and various metallic species from aqueous
solution with high efficiency. In this work, experiments were conducted to
assess the feasibility of using liquid membranes to extract pesticides from
rinsewaters typical of those generated by fertilizer/agrichemical dealers. A
liquid membrane emulsion containing 10% NaOH as the internal reagent phase was
used to extract herbicides from aqueous solution at a continuous phase:emulsion
ratio of 5:1. Removals of 2,4-D, MCPA, Carbaryl, Diazinon, and Atrazine were
85.4, 61.2, 80.2, 73.9, and 92.9%, respectively, after 15-20 minutes mixing time.
INTRODUCTION
There are over 14,000 agricultural chemical dealers ("dealers") in the
United States. Dealers sell fertilizers and/or pesticide products; they also
custom mix and apply these products. Incidental spillage of fertilizer/pesticide
products may occur during handling and can result in the accumulation of
hazardous chemicals in the soil, surface water and groundwater. Chemicals can
also accumulate in these media when tanks and application equipment are rinsed
with water and the rinsewater is not disposed of or recycled properly. As
dealers continue their efforts to contain, collect, and recycle their wastes and
spills, there will be an increased need for technologies to treat that portion
of the wastes and spills that cannot be recycled.
The National Fertilizer and Environmental Research Center (NFERC) has
recognized that the waste treatment problems currently facing dealers are real
and cannot be ignored. Therefore, in March 1990, a multidisciplinary NFERC
project team was organized to identify, research, develop, and demonstrate waste
treatment and site remediation technologies for dealers. The work reported in
this paper was undertaken as part of the research phase of this program.
68
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OBJECTIVE
The primary objective of this research project was to assess the
feasibility of using liquid membrane emulsions to remove herbicides from aqueous
solutions similar to the rinsewaters generated at dealer sites. Several
experiments were also run with aqueous solutions of phenol or acetic acid to gain
experience in the experimental techniques involved in the preparation and
handling of liquid membrane emulsions.
The five herbicides investigated in this study were:
(1) 2,4-D (2,4-dichlorophenoxyacetic acid)
(2) MCPA (4-chloro-O-tolyloxyacetic acid)
(3) Carbaryl (1-napthyl N-methylcarbamate)
(4) Atrazine (2-chloro-4-ethylamino-6-isopropylamino-l,3,5-triazine)
(5) Diazinon (0,0-diethyl-0-[2-isopropyl-4-methyl-
6-pyrimidyl]phosphoro-thioate)
BACKGROUND
General Description of Liquid Membranes: Liquid membranes were invented
by Norman N. Li in 1968 (1-3). Liquid membranes are made by forming an emulsion
of two immiscible phases (the membrane and internal phases) and then dispersing
the emulsion into a third phase (the continuous phase). Usually, the internal
phase and the continuous phase are miscible. If the liquid membrane emulsion is
to remain stable, the membrane phase must not be miscible with either the
internal or the continuous phase. To maintain the integrity of the emulsion
during an extraction experiment, the membrane phase usually contains certain
surfactants, additives as stabilizing agents, and a base material which is a
solvent for all the ingredients. Since the compositions of the membrane and the
internal phase can be varied, liquid membranes can be tailor-made to meet
specific requirements for a given application (4-7).
When the liquid membrane is dispersed by agitation in the continuous phase,
many small globules of emulsion are formed (Figure 1). Their size depends on the
nature and concentration of the surfactants in the membrane, the emulsion
viscosity, and the mode and intensity of mixing. In general, the globule size
is controlled in the range from 0.1 to 1 millimeter in diameter. A large number
of globules of emulsion are formed to produce a large membrane surface area for
rapid mass transfer for species from the continuous phase to the internal phase
of the emulsion. In addition, many smaller droplets, typically 1 micron in
diameter, are encapsulated within each globule. A variety of chemical species
can be trapped and concentrated in the internal phase and subsequently disposed
of or recovered for reuse or recycle.
Liquid Membrane Separation Technologies: Liquid membrane technology is
very promising for a variety of applications. Examples of these applications
include: the separation of hydrocarbons (8, 9) and metal ions from water
(10-25); hydrometallurgy (10-25) and wastewater treatment applications
(13, 26-36); and biochemical engineering, such as the encapsulation of enzymes
and bacteria (37, 38). Liquid membrane technology currently has two commercial
applications; one in zinc extraction and recovery (4) and the other in oil
production as a well control fluid (39, 40).
69
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Liquid Membrane Extraction Mechanisms: The effectiveness of the liquid
membrane process can be enhanced by utilizing "facilitated transport" mechanisms
to maximize both the flux through the membrane and the capacity of the internal
phase for trapping and concentrating the diffusing species (7). One type of
facilitated transport consists of carrying the diffusing species across the
membrane by incorporating liquid ion exchange reagents in the membrane. This
type of carrier-mediated transport can be illustrated by the separation of metal
ions from wastewater or ore-leaching solutions. A conceptualized drawing of a
liquid membrane "capsule" for extracting copper ions from wastewater is given in
Figure 2. Extraction of copper ions occurs at the membrane/continuous phase
interface. A liquid hydroxyoxime-type ion-exchange reagent specific for copper
ions is incorporated in the membrane phase. Stripping of copper ions from the
ion-exchange reagent occurs at the membrane/internal phase interface by 10%
H2S04. The overall reaction represents an exchange of a copper ion for two
hydrogen ions. The copper is effectively trapped in the interior of the liquid
membrane by the large excess of hydrogen ions (16-21).
One important advantage of the liquid membrane process for metal extraction
lies in the concurrent extraction and stripping in a single stage rather than in
two separate stages as required by solvent extraction. In addition, by
concurrently extracting and stripping, the liquid membrane process drives the
extraction by removing the complexed ions as they are formed, thereby removing
the equilibrium limitation inherent in solvent extraction. Another benefit
resulting from the nonequilibrium feature of the liquid membrane process is the
significant reduction of the reagent inventory required for the extraction
process.
The second type of facilitated transport is illustrated by the removal of
oil-soluble contaminants such as ammonia (26, 30, 32-34), phenol and other
organic acids such as acetic acid (32-36) from aqueous solution. In these cases,
the membrane phase does not contain a liquid ion-exchange reagent. Rather, the
extraction is driven by minimizing the concentration of the diffusing species in
the internal phase. This is accomplished by reacting the diffusing species with
a reagent in the internal phase to form a product(s) incapable of diffusing back
through the membrane.
This type of facilitated transport can be illustrated by the separation of
phenol from wastewater (Figure 3). In this case, sodium hydroxide (10% NaOH) is
encapsulated inside the internal phase as the reagent which reacts with phenol.
The phenol first dissolves in the membrane phase from the continuous phase and
then diffuses to the interface between the membrane phase and the Internal phase.
At this interface, the phenol reacts with 10% NaOH to form sodium phenolate that
is insoluble in the membrane phase. As a result, the concentration of phenol at
the membrane/internal phase interface is maintained at zero, allowing a
continuous driving force for permeation through the membrane. In addition to
phenol, contaminants which can be removed by reaction with sodium hydroxide in
the internal phase are cresols, carboxylic acids, and hydrogen sulfide.
In principle, the liquid membrane extraction process should be broadly
applicable to many acidic species containing an ionizable chemical functional
group(s). These species include many types of herbicides. Two of the five
herbicides investigated in this study are representative of these acidic species,
i.e., 2,4-D and MCPA. The other three herbicides, i.e., Carbaryl, Diazinon, and
Atrazine, were chosen for study because each are soluble in organic solvents and,
furthermore, each are known to hydrolyze rapidly in alkaline solution.
70
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EXPERIMENTAL
Preparation of the Liquid Membrane Emulsion: The membrane phase consisted
of a mixture of surfactant (4%) and solvent (96%). The surfactant was EGA 4360
(Paramins Co., Paramus, NJ), a polyamine with an average molecular weight of
1500. The solvent used was Low Odor Paraffin Solvent (LOPS); this solvent is an
isoparaffin hydrocarbon (Exxon, Houston, TX). All the herbicides were analytical
grade and used as received (ChemService, Inc., West Chester, PA).
Liquid membrane emulsions for use in bench-scale batch tests were prepared
by extensive mixing of the membrane and internal phase (10% NaOH) in a Waring
blender. The internal phase was mixed with the membrane phase on a 1:1 weight
ratio to form a water-in-oil emulsion. The mixing was accomplished at 10,000 rpm
for 6 minutes to ensure complete encapsulation. The resulting emulsion was mixed
with the continuous phase (aqueous solutions of phenol, acetic acid, or
herbicides) at a continuous phase:emulsion ratio of 5:1 in a baffled 2-liter
resin kettle. Mixing was accomplished with 2 marine-type propellers attached to
a variable speed stirrer via a 1/4 inch stainless steel stirring rod. The mixing
speed ranged from 400 to 600 rpm for the phenol experiments and 420-440 rpm for
the acetic acid and herbicide experiments. The mixing speed was monitored by a
hand-held digital tachometer (Shimpo Model DT-201). The length of all
experiments was 20 minutes. Samples were taken at 1, 5, 10, 15 and 20 minutes
via a stopcock at the bottom of the resin kettle. All experiments were conducted
at ambient temperature.
RESULTS AND DISCUSSION
Phenol and Acetic Acid Solutions
Extraction of Phenol from Aqueous Solution (35,36): Figure 4 shows data
from an experiment to assess the effect of mixing speed (rpm) on the extraction
of phenol. Three observations can be noted:
(1) The percent extraction values at the 1 minute sampling time
decrease as the mixing speed decreases.
(2) The maximum extraction value of each curve shifts to longer
sampling times as the mixing speed decreases.
(3) The slopes of the extraction curves after about 5 minutes
increase from nearly zero at the low rpm to larger negative values
as the mixing speed increases.
As the mixing speed increases two phenomena occur: (1) the emulsion
globule size decreases, and (2) the rate at which globules are broken increases.
A smaller globule size will lead to more interfacial transfer area between the
continuous phase and the liquid membrane, thus allowing the extraction to occur
at a higher rate. In addition, the higher rate of shear and subsequent higher
rate of breakage of globules at the higher rpm values allows more leakage of the
phenol ate ion back into the continuous phase from the internal phase of the
liquid membrane emulsion.
Extraction of Acetic Acid from Aqueous Solution (36): Aqueous solutions
of acetic acid (5000, 3000, and 1000 ppm) were used as the continuous phase for
the three extraction runs shown in Figure 5. Percent extraction values are
plotted versus mixing time. The results shown in Figure 5 indicate that as the
71
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concentration of acetic acid in the continuous phase increases the extraction
rate decreases. This did not appear to be the case in the experiments described
above where phenol was the pure component in the continuous phase. The
difference in the results from the acetic acid and phenol extraction runs is most
likely due to the difference in the partition coefficient values of the
components between the membrane and continuous phases. In the case of acetic
acid, its solubility in the membrane phase is likely the controlling factor.
Herbicide Solutions
2,4-D: Table 1 contains data from the first extraction run where an
aqueous solution containing approximately 100 ppm 2,4-D was used as the
continuous phase. After 1 minute mixing time, the concentration of 2,4-D
decreased from 96.8 to 30.7 ppm, a reduction of 68.2%. After 20 minutes mixing
time, the amount of 2,4-D extracted from the continuous phase by the liquid
membrane increased to a value of 85.4%. Based upon the results summarized in
Table 1, no leakage of 2,4-D from the internal phase of the membrane back into
the continuous phase occurred during this experiment.
HCPA: Table 2 contains data from the second extraction run where an
aqueous solution containing approximately 100 ppm MCPA was used as the continuous
phase. After 1 minute mixing time, the concentration of MCPA decreased from 96.1
to 67.4 ppm, a reduction of only 29.9%. However, after 15 minutes mixing time,
the amount of MCPA extracted from the continuous phase increased to 61.2%.
Unfortunately, some leakage of the MCPA from the internal phase of the liquid
membrane emulsion back into the continuous phase occurred during this experiment
based on the fact that the concentration of MCPA in the continuous phase
increased from 37.3 ppm at 15 minutes to 41.4 ppm at 20 minutes total mixing
time.
Diazinon: Table 3 contains data from the third extraction run where an
aqueous solution containing approximately 30 ppm diazinon was used as the
continuous phase. After 1 minute mixing time, the concentration of diazinon
decreased from 28.3 to 14.7 ppm, a reduction of 48.1%. After 15 minutes mixing
time, the amount of diazinon extracted from the continuous phase by the liquid
membrane emulsion increased to a value of 73.9% and thereafter remained
essentially constant. No significant leakage of diazinon from the internal phase
of the membrane back into the continuous phase is indicated by the data given in
Table 3.
Carbaryl: Table 4 contains data from the fourth extraction run
where an aqueous solution containing approximately 30 ppm carbaryl was used as
the continuous phase. After 1 minute mixing time, the concentration of carbaryl
decreased from 31.3 to 10.3 ppm, a reduction of 67.1%. After 20 minutes mixing
time, the amount of carbaryl extracted from the continuous phase increased to a
value of 80.3%. No leakage of carbaryl from the internal phase of the membrane
into the continuous phase was indicated by the experimental data.
Atrazine: Table 5 contains data from the fifth and final extraction run
where an aqueous solution containing approximately 30 ppm atrazine was used as
the continuous phase. After 1 minute mixing time, the concentration of atrazine
in the continuous phase decreased by 64.9%. However, after 15 minutes mixing
time, the amount of atrazine extracted from the continuous phase by the liquid
membrane increased to a value of 92.9%. Some leakage of atrazine from the
internal phase back into the continuous phase is indicated by the data given in
Table 5 at the 20 minute mark.
72
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SUMMARY
The major results obtained from this study may be summarized as follows:
(1) More than 99% of phenol can be extracted from aqueous solution
after approximately 1 minute with a liquid membrane emulsion
containing 10% NaOH as the internal reagent phase.
(2) Acetic acid can also be extracted by the liquid membrane emulsion
but at a slower rate (5-10 minutes mixing time).
(3) The liquid membrane emulsion containing 10% NaOH as the internal
reagent phase can extract herbicides from aqueous solution at a
continuous phaseremulsion ratio of 5:1. Removals of 2,4-D, MCPA,
Carbaryl, Diazinon, and Atrazine were 85.4, 61.2, 80.2, 73.9, and
92.9%, respectively, after 15-20 minutes mixing time.
CONCLUSION
Based upon the exploratory work reported in this paper, it appears that
liquid membrane technology can be used to extract herbicides from aqueous
solution. The types of herbicides that can be extracted by the particular
membrane composition reported in this paper are limited to those that will form
an ionized species or hydrolyze in alkaline solution. Further work is required
to determine whether other types of herbicides are amenable to extraction from
aqueous solution by different liquid membrane compositions. Also, it will be
useful to analyze the composition of the internal reagent phase, after the liquid
membrane emulsion is broken, to perform a material balance calculation and
identify degradation products.
73
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Table 1. Extraction of 2,4-D from Aqueous Solution
Mixing Time (min) Concentration fppm)
0 96.8
1 30.7 (68.2% Removed)
5 16.6
10 14.9
15 16.3
20 14.1 (85.4% Removed)
Table 2. Extraction of MCPA from Aqueous Solution
Mixing Time (mini Concentration (pom)
0 96.1
1 67.4 (29.9% Removed)
5 62.2
10 52.4
15 37.3 (61.2% Removed)
20 41.4
74
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Table 3. Extraction of Diazinon from Aqueous Solution
Mixing Time (min) Concentration (ppm)
0 28.3
1 14.7 (48.1% Removed)
5 10.3
10 9.3
15 7.4 (73.9% Removed)
20 7.6
Table 4. Extraction of Carbaryl from Aqueous Solution
Mixing Time (min) Concentration (ppm)
0 31.3
1 10.3 (67.1% Removed)
5 14.7
10 11.3
15 9.4
20 6.2 (80.2% Removed)
75
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Table 5. Extraction of Atrazine from Aqueous Solution
Mixing Time (mini Concentration (ppm)
0 29.8
1 10.5 (64.9% Removed)
5 6.3
10 4.1
15 2.1 (92.9% Removed)
20 4.6
76
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LITERATURE CITED
1. Li, N. N., "Separating Hydrocarbons with Liquid Membranes", U.S. Patent
3,410,794 (November 12, 1968).
2. Li, N. N., "Permeation Through Liquid Surfactant Membranes", AIChE J.
17(2), 459 (1971).
3. Li, N. N., "Facilitated Transport Through Liquid Membranes-An Extended
Abstract", J. Membr. Sci. 3, 265 (1978).
4. Frankenfeld, J. W.; Li, N. N., "Recent Advances in Liquid Membrane
Technology", in Handbook of Separation Process Technology, Wiley, New
York, p. 840 (1987).
5. Cussler, E. L.; Evans, D. F., "How to Design Liquid Membrane Separations",
Sep. Purif. Methods 3, 399 (1974).
6. Del Cerro, C.; Boey, D., "Liquid Membrane Extraction", Chemistry and
Industry, 681 (November 7, 1988).
7. Matulevicius, E. C.; Li, N. N., "Facilitated Transport Through Liquid
Membranes", Sep. Purif. Methods 4, 73 (1975).
8. Cahn, R. P.; Li, N. N., "Hydrocarbon Separation by Liquid Membrane
Processes", in Membrane Separation Processes, P. Mears (Ed.), Chap. 9,
Elsevier, New York (1976).
9. Li, N. N., "Separation of Hydrocarbons by Liquid Membrane Permeation",
Ind. Eng. Chem. Proc. Res. Dev. 10, 215 (1971).
10. Cahn, R. P.; Frankenfeld, J. W.; Li, N. N.; Naden, D.; Subramanian, K. N.,
"Extraction of Metals by Liquid Membranes", in Recent Developments in
Separation Science, N. N. Li (Ed.), Vol. VI, p. 51, CRC Press, Boca Raton,
Florida (1981).
11. Gu, Z. M.; Wasan, D. T.; Li, N. N., "Liquid Surfactant Membranes for Metal
Extractions", Faraday Discuss. Chem. Soc. 77, 1 (1984).
12. Hayworth, H. C.; Ho, W. S.; Burns, Jr., W. A.; Li, N. N., "Extraction of
Uranium from Wet Process Phosphoric Acid Using Liquid Membranes", Sep.
Sci. Technol. 18, 493 (1983).
13. Frankenfled, J. W.; Li, N. N., "Waste Water Treatment by Liquid Ion
Exchange in Liquid Membrane Systems", in Recent Developments in Separation
Science, Li, N. N. (Ed.), Vol. II, p. 285, CRC Press, Boca Raton, Florida
(1977).
14. Hochhauser, A. M.; Cussler, E. L., " Concentrating Chromium with Liquid
Surfactant Membranes", AIChE Symp. Ser. 71, 136 (1975).
15. Bock, J.; Valint, Jr., P. L., "Uranium Extraction from Wet Process
Phosphoric Acid. A Liquid Membrane Approach", Ind. Eng. Chem. Fundam. 21,
417 (1982).
77
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16. Li, N. N.; Cahn, R. P.; Naden, 0.; Lai, R. W., " Liquid Membrane Processes
for Copper Extraction", Hydrometallurgy 9, 277 (1983).
17. Strzelbicki, J.; Charewicz, W., "The Liquid Surfactant Membrane Separation
of Copper, Cobalt and Nickel from Multicomponent Aqueous Solutions",
Hydrometallurgy 5, 243 (1980).
18. Volkel, W.; Halwacks, W.; Schugerl, K., "Copper Extraction by Means of a
Liquid Surfactant Membrane Process", J. Membr. Sci. 6, 19 (1980).
19. Martin, T. P.; Davies, G. A., "The Extraction of Copper from Dilute
Aqueous Solutions Using a Liquid Membrane Process", Hydrometallurgy 2, 315
(1977).
20. Frankenfeld, J. W.; Cahn, R. P.; Li, N. N., "Extraction of Copper by
Liquid Membranes", Sep. Sci. Technol. 16, 385 (1981).
21. Lee, K. H.; Evans, D. F.; Cussler, E. L., "Selective Copper Recovery with
Two Types of Liquid Membranes", AIChE J. 24, 860 (1978).
22. Fuller, E. J.; Li, N. N., "Extraction of Chromium and Zinc from Cooling
Tower Slowdown by Liquid Membranes", J. Membr. Sci. 18, 251 (1984).
23. Teramoto, M.; Tohno, N.; Ohnishi, N.; Matsuyama, H., "Development of a
Spiral-Type Flowing Liquid Membrane Module with High Stability and its
Application to the Recovery of Chromium and Zinc", Sep. Sci. Technol. 24,
981 (1989).
24. Cahn, R. P.; Li, N. N., "Metal Extraction by Combined Solvent and LM
Extraction", U. S. Patent 4,086,163 (April 25, 1978).
25. Xinchang, Z.; Linain, L.; Jianjun, G.; Fusheng, L., "A Study of Extracting
Vanadium from Wastewater by Emulsified Liquid Membrane Process", Water
Treatment 2, 214 (1987).
26. Cahn, R. P., Li, N. N.; Minday, R. M., "Removal of Ammonium Sulfide from
Wastewater by Liquid Membrane Process", Environ. Sci. Technol. 12, 1051
(1978).
27. Li, N. N.; Cahn, R. P.; Shrier, A. L., "Use of Liquid Membrane Systems for
Selective Ion Transfer", U. S. Patent 4,292,181 (September 29, 1981).
28. Kitagawa, T.; Nishikawa, Y.; Frankenfeld, J. W.; Li, N. N., "Wastewater
Treatment by Liquid Membrane Process", Environ. Sci. Technol. 11, 602
(1977).
29. Ruppert, M; Draxler, J.; Marr, R., "Liquid-Membrane-Permeation and its
Experiences in Pilot-Plant and Industrial Scale", Sep. Sci. Technol. 23,
1659 (1988).
30. Downs, H. H.; Li, N. N., "Extraction of Ammonia from Municipal Waste Water
by the Liquid Membrane Process", J. Separ. Proc. Technol. 2(4), 19 (1981).
78
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31. Li, N. N.; Chan, R. P.; Shrier, A. L., "Liquid Membrane Process for the
Separation of Aqueous Mixtures", U. S. Patent 3,779,907 (December 18,
1973).
32. Li, N. N.; Cahn, R. P., "Process for Removing the Salt of a Weak Acid and
a Weak Base From Solution", U. S. Patent 4,029,744 (June 14, 1977).
33. Chan, C. C.; Lee, C. J., "A Mass Transfer Model for the Extraction of Weak
Acids/Bases in Emulsion Liquid-Membrane Systems", Chem. Eng. Sci. 42, 83
(1987).
34. Lee, C. J.; Chan, C. C., "Extraction of Ammonia from a Dilute Aqueous
Solution by Emulsion Liquid Membranes. 1. Experimental Studies in a
Batch System", Ind. Eng. Chem. Res. 29, 96 (1990).
35. Cahn, R. P.; Li, N. N., "Separation of Phenol from Waste Water by the
Liquid Membrane Technique", Sep. Sci. 9, 505 (1974).
36. Terry, R. E.; Li, N. N., "Extraction of Phenolic Compounds and Organic
Acids by Liquid Membranes", J. Membr. Sci. 10, 305 (1982).
37. Mohan, R. R.; Li, N. N., "Nitrate and Nitrite Reduction by Liquid
Membrane-Encapsulated Whole Cells", Biotechnol. Bioeng. 17, 1137 (1975).
38. Mohan, R. R.; Li, N. N., "Reduction and Separation of Nitrate and Nitrite
by Liquid Membrane-Encapsulated Enzymes", Biotechnol. Bioeng. 16, 513
(1974).
39. U. S. Patent 4,359,391 (1982).
40. U. S. Patent 4,397,354 (1983).
79
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CO
o
Oil
Surfactant
Membrane
Aqueous Feed
Aqueous Reagent
Droplets
Emulsion
Globules
Figure 1. Dispersion of Liquid Membrane Emulsion20
-------
00
Internal
Aqueous
Droplets
(+Stripping
Agent)
Oil
Acid
(Stripping
Agent)
Aqueous
Feed
Liquid
Membrane
Ugand (R) + Surfactant
Figure 2. Cooper Transfer In a Liquid Hembrane Globule
20
-------
liquid Membrane
Surfactant
Hydrophobic Hydrophlllc
Solvent
Surfactants
Additives
CO
ro
Phenol Reaction
Droplets
Phenol + NaOH
•»• Sodium Phenolale
I Won Permeable)
Aoueous Feed Outside
(Continuous Pliate)
Figure 3. Liquid Hembrane System for Phenol Removal
20
-------
PERCENT EXTRACTION OF PHENOL
S
to
c
(D
n
3
tO
-o
(D
o
(D
X
rt
S
3-
(D
O
-------
100
CO
a
9
o
o
0
30
lOOOppm
0 11
MbdflflTIiM(Uln)
-- MQOppm
19
8000 ppm
Figure 5. Effect of Concentration on the Extraction of Acetic Acid
-------
Field and Laboratory Evaluations of an Activated
Charcoal Filtration Unit
by
Joseph H. Massey, Terry L. Lavy, and Briggs W. Skulman
Department of Agronomy, University of Arkansas, Fayetteville
ABSTRACT
An activated charcoal filtration unit was designed to remove pesticides
from leftover pesticide solutions and rinsates generated under farm-like
conditions. The system, fabricated for less than $1200 using readily available
components, effectively removed the pesticides atrazine, benomyl, carbaryl,
fluometuron, metolachlor, and trifluralin from wastewater. A total of 2253 L of
wastewater were treated using the system. Of these 1768 L were generated from
washing out the spray tank while 485 L stemmed from leftover pesticide solutions
that were mixed, but not applied. Typical initial pesticide concentrations in
the wastewater were on the order of 300 to 1000 parts per million (ppm). The
final pesticide concentrations remaining after charcoal filtration were generally
less than 10 ppm. Approximately 1514 L of wastewater were treated with 23 kg of
charcoal before the charcoal was replaced. This resulted in an estimated
pesticide loading rate of 0.05 to 0.10 kg pesticide active ingredient per kg
activated charcoal. Incubation of alachlor-treated charcoal with a mixed culture
of microorganisms resulted in approximately a 50% loss of alachlor after 50 d.
These results suggest that the degradation of alachlor sorbed to charcoal does
occur but more research is needed to determine if it is a feasible alternative
to incineration for spent charcoal. A reduced adsorption of methylene blue and
alizarin red dye with increasing amounts of trifluralin sorbed to charcoal
occurred. Activated charcoal treated with more than 200 mg/g trifluralin
adsorbed considerably less of these dyes than the control where no trifluralin
was added. The adsorption of malachite green dye was less affected by these
trifluralin concentrations. These results suggest that methylene blue or
alizarin dye might be used to rapidly assess the remaining adsorptive capacity
of a activated charcoal used to treat pesticide-laden wastewater.
INTRODUCTION
Several researchers have successfully used activated charcoal to remove
pesticides from leftover solutions and rinsates. Nye (1988) developed a
flocculation/sedimentation and filtration process that reduced 18925 L of
wastewater to 379 L of sludge and 91 kg of spent carbon. Dennis (1988) built a
similar system based on the CARBOLATOR 35 water purification unit. After 20 h
of filtration with 18 kg of Calgon-300 charcoal, 4 out of 6 pesticides initially
present in 1552 L of water were not detectable.
In each of these systems, pesticides were filtered from wastewater using
granular activated charcoal (GAC). After filtration, the wastewater could be
reused as a diluent or returned to the environment with minimal impact. Although
activated charcoal has proven to be quite effective at removing many different
pesticides from wastewater, more research is needed in order to optimize the
charcoal adsorption process.
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One major drawback of activated charcoal filtration is that the pesticides
are adsorbed, not destroyed, and contaminated charcoal is produced. This
contaminated charcoal presents the problem of proper disposal in order to prevent
environmental contamination. While regeneration of the charcoal is possible, it
is not economically feasible when less than 225 kg spent charcoal/day are
generated (Zanitsch and Stenzel, 1978). For this reason spent charcoal generated
in small quantities is normally incinerated.
An alternative disposal treatment for spent charcoal may involve the
degradation of sorbed pesticides by microorganisms. The degradation of organic
pollutants in soil is frequently the result of microbial activity. However, the
sorption of some organics by soil constituents has been found to reduce the
availability of organic molecules to microorganisms and decrease the rate of
degradation (Miller and Alexander, 1991). The typical diameters of activated
charcoal micropores range from 10 to 1000 angstroms while most bacterial cell
diameters range from 5000 to > 10,000 angstroms. Consequently, bacteria are
physically excluded from the micropore structure of activated charcoal (Perrotti
and Rodman, 1974). For this reason it is not clear that microbial degradation
of pesticides sorbed to spent charcoal will be feasible. However, the successful
degradation of pesticides sorbed to soil (Kilbane et al., 1983; Somich et al.,
1990) and peat moss (Mullins et al., 1989) suggests that the microbial
degradation of pesticides sorbed to charcoal deserves investigation.
Simple techniques for assessing the adsorptive capacity of activated
charcoal are needed in order to optimize the filtration of pesticide wastes.
Although a thin-layer chromatography method was developed to detect pesticides
in filtered effluent (Dennis, 1988), this is likely impractical for use under
farm conditions. Another approach may be to use dyes to indicate when activated
charcoal no longer has the capacity to effectively adsorb pesticides from
solution. The use of dyes to assess the adsorptive capacity of activated
charcoal has proven to be helpful in many industrial situations (Hassler, 1974).
To qualify for use, the dyes should have adsorptive characteristics similar to
those of the chemicals being adsorbed.
PURPOSE AND OBJECTIVES
The overall goal of this research was to further the progress towards an
economical and practical pesticide waste disposal technology. The specific goals
were to: a), fabricate and field test a pesticide rinsate disposal unit based
on activated charcoal filtration technology, b). determine the feasibility of
microbially degrading pesticides sorbed to spent charcoal, and c). determine if
visual assays could be used to assess the remaining adsorptive capacity of
activated charcoal.
MATERIALS AND METHODS
Activated Charcoal Filtration Unit
A schematic diagram of the activated charcoal filtration unit (ACFU) is
given in Figure 1. The system, like that described by Dennis (1988), was
fabricated using readily available materials and was simple in design. The
fiberglass tank was filled with 23 kg of Cullar-D granular activated charcoal
(American Norit Co., Inc.; Jacksonville, FL 32205). A 1/2 hp electric
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centrifugal pump produced a flow rate through the charcoal filter of 0.65 L/s.
A 30 m paper pre-filter was placed before the charcoal filter to remove sediment
and debris from the wastewater. By mounting the pump and cartridge filter
housing onto a wagon and using a hand-truck for the fiberglass tank, the unit was
easily transported to the pesticide mixing/loading site.
Actlvated
Charcoal FIIter
Waste Drum
Figure 1. Schematic of the activated charcoal
filtration unit used for rinsate disposal
Two modifications were made
pressure cutoff switch was added.
the water pressure dropped below
installed which would not allow
to the electric water pump. First, a low-
This safety switch shut the system down when
10 psi. Also, a manual reset button was
the pump to automatically restart after
overheating without the assistance of the operator. These modifications
increased the level of equipment protection and eliminated the need for constant
supervision of the ACFU while in use. The retail cost of the ACFU, including
modifications, was about $1200.
Pesticide-laden wastewater generated during 1990 on the University of
Arkansas Main Agricultural Experiment Station, Fayetteville (MAES) was stored in
208 L teflon-lined drums. The wastewater stemmed from two primary sources:
leftover pesticide solutions and rinsates from cleaning spray equipment. Prior
to filtration, the wastewater was mixed, solution pH and temperature measured,
and a sample collected for time-zero analysis using either gas or high
performance liquid chromatography. During filtration, effluent from the charcoal
filter was circulated back into the containment drum. At various time intervals,
more samples were collected from the bulk solution. As a general rule, fil-
tration was continued until the wastewater was clear and odorless (ca. 3 to 5 h).
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Microbial Degradation of Spent Charcoal
A system was designed to aid in determining the feasibility of microbial
degradation of pesticides sorbed to spent charcoal. The system was similar to
that reported by Wolf and Legg (1984) except that no C02 trapping was involved.
The degradation of Lasso 4EC herbicide (alachlor, Monsanto Co., St. Louis, MO
63167) sorbed to activated charcoal was measured by using a gas chromatographic
rather than a radioisotopic technique.
Alachlor-amended charcoal1 was prepared to have a concentration of 24,820+
1816 g alachlor/g GAC. Approximately 60 g (wet weight) of the amended charcoal
was placed into a 125 mL erlenmeyer flask containing 25 mL of nutrient broth
solution and 1 mL of a 105 soil dilution. Six replications of the amended
charcoal treatment were employed. Aeration was provided by bubbling room air
through the samples. The samples were incubated at 33 ± 1 C in a water bath.
Two controls were included in the study. One was a charcoal control which
contained similar amounts of charcoal, nutrient broth, and soil inoculant but had
no alachlor added. A water control consisted of 30 mL of water containing 620
± 89 ppm of alachlor with nutrient broth solution and soil inoculant but with
no charcoal present. Five repetitions of these controls were incubated with the
alachlor-amended charcoal samples.
Adsorptivitv Assays for Used Charcoal
For the first series of tests Treflan herbicide and methylene blue dye
(85%, Matheson Coleman & Bell, Norwood, OH) were used. To 1 g quantities of
oven-dried charcoal dried (24 h at 105°C), various amounts of Treflan herbicide
solution were added. Final concentrations of trifluralin ranged from 0 to 384
mg trifluralin/g charcoal. Three replications per concentration were used.
To the trifluralin-amended charcoal, 5 mL of a 0.021 M methylene blue dye
solution (dissolved in a 0.22 M sodium phosphate monobasic buffer solution
adjusted to pH 6.5) was added. The glass culture tubes were capped and shaken
at 12 rpm for 15 min at room temperature. After measuring the absorbance of the
dye remaining in solution, the dye concentration was estimated using a standard
curve.
Similar studies were conducted using 0.021 M malachite green dye (99%,
Eastman Kodak Co., Rochester, NY) and 0.022 M alizarin red dye (J.T. Baker
Chemical Co., Phillipsburg, NJ). For the alizarin red study, the buffer
concentration was reduced to 0.04 M to prevent precipitation of the dye.
RESULTS AND DISCUSSION
Field Evaluation of the ACFU
About 485 L of leftover pesticide solutions and 1768 L of rinsates were
treated using the ACFU. These figures reveal that 79% of the wastewater treated
stemmed from the cleaning of spray equipment. There were 3785 L of pesticide
solutions mixed during the 1990 growing season. Of these, 485 L or 13% were
1A11 studies used Cullar-D activated charcoal like that used in the ACFU.
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returned unused to the waste drums. The average volume of the leftover solutions
was 23 ± 23 L while that of the rinsates was 87 ± 34 L.
The ACFU effectively removed the commonly applied herbicides AAtrex Nine-0
(atrazine, CIBA-GEIGY Corp., Greensboro, NC 27409), Bicep 4.5L (metolachlor,
CIBA-GEIGY Corp., Greensboro, NC 27409), and Treflan EC (trifluralin, Elanco
Products Co., Indianapolis, IN 46285) (Figure 2) and other pesticides including
Benlate 50% WP fungicide (benomyl, DuPont Co. Inc., Wilmington, OE 19898), Sevin
insecticide (carbaryl, Union Carbide Co. Inc., Res. Triangle Park, NC 27709) ,
and Cotoran herbicide (fluometuron, CIBA-GEIGY Corp., Greensboro, NC 27409)
(Figure 3). Typical initial pesticide concentrations were on the order of 300
to 1000 ppm while final concentrations after filtration were < 10 ppm.
An estimated 0.05 to 0.10 kg of pesticide active ingredient could be
adsorbed by each kg of GAC. These values are based on the fact that after 1514
L of wastewater had been filtered, the 23 kg of GAC no longer effectively removed
pesticides from solution. At this point the spent charcoal was replaced.
Solution Cone, ppm
" trff II*-BI In
20 40 60 80 100 130
Minutes of Filtration
HO 160 180
Figure 2. Removal of three herbicides using
activated charcoal filtration.
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Solution Cone, ppm
20 30 40 50
Minutes of Filtration
60
70
Figure 3. Removal of three pesticides using
activated charcoal filtration.
Other than adsorption onto the charcoal, there were at least two other
avenues of pesticide dissipation not explored in this study. First, some of the
pesticides were trapped by the 30 m paper pre-filter. Solid-carrier pesticide
formulations (e.g. AAtrex Nine-0) were trapped to some degree by the filter.
Moreover, bright yellow stains formed on the paper filters, indicating that
Treflan herbicide was being sorbed. Besides the spent charcoal, these
contaminated filters are another source of contaminated material which will have
to be properly disposed.
Volatilization from solution is a potential avenue of dissipation for some
pesticides. Controlling factors of volatilization from water include the
solubility, molecular weight, and vapor pressure of the pesticide and the nature
of the air-water interface through which it must pass, the turbulence generated
during the recirculation of the wastewater would likely enhance volatilization.
Of the pesticides involved in this study, only trifluralin has a Henry's Law
Constant great enough to suggest that volatilization from solution might be a
significant problem (Jury et al., 1987).
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Hicrobial Degradation of Spent Charcoal
Figure 4 presents data generated from incubating alachlor amended charcoal
under conditions which should favor microbial growth. The degradation of
alachlor on charcoal occurred at a slow, steady rate. After 21 d of incubation
slightly less than 70% of the originally applied alachlor still remained on the
charcoal. Thirty-nine days of incubation resulted in a 52% retention of the
alachlor initially applied to the charcoal while the water control retained
approximately 46%. After 59 d the amended charcoal retained 43% while the water
control retained 33% of the initial alalchlor. These data suggest a half-life
of about 50 d for the alachlor sorbed to charcoal.
X of Alachlor Homfnlng
0 3
9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 SO
Days of Incitotron
Figure 4. Degradation of alachlor sorbed to
activated charcoal.
While these data are preliminary, results suggest that the degradation of
alachlor sorbed to charcoal via microbial action can occur. Alachlor is degraded
in soil primarily by microorganisms and its losses due to volatility are low
(Humburg, 1989). This study did not address the possibility that degradation may
have occurred through chemical reactions.
Until the feasibility of microbially degrading spent charcoal is fully
determined, spent charcoal can be incinerated. For this reason, an estimated cost
of disposing the spent charcoal via incineration at the Environmental Systems
Company (ENSCO) El Dorado, AR plant was calculated. According to an ENSCO
representative, charcoal containing pesticides can be incinerated for $2.10/kg.
Transportation costs normally run $25/208-1 drum with a $50 stop-fee. An
analytical determination of the drum contents is also required ($300/sample).
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About 23 kg of spent charcoal was generated by filtering 1514 L of
wastewater. Given an apparent density of 470 kg/m3, a 208 L drum of charcoal
would weigh about 97 kg. At $2.10/kg disposal fee, this would cost about $210,
plus $75 for shipping and $300 for analytical costs. Since there is a minimum
invoice of $1000, at least 2 drums would be required for economical reasons. Two
drums would contain 200 kg of charcoal, resulting in a total cost of $1120 to
dispose of charcoal (including transportation and analytical costs). Excluding
the cost of charcoal, this amount of charcoal could treat about 13000 L of
wastewater at a cost of about $0.09/L.
Adsorptivity Assays for Used Charcoal
Figure 5 gives the results of the dye test studies. All three dyes
experienced reduced adsorption with increasing trifluralin concentration on the
charcoal. Compared to methylene blue and alizarin red dyes, malachite green dye
adsorption was not as affected by increasing amounts of trifluralin. For
trifluralin concentrations less than 200 mg/g, there was little difference in the
amount of dye adsorbed compared to the control. Trifluralin concentrations
greater than 200 mg/g resulted in greatly diminished adsorption of the dyes.
mg dy« adaorbod/g
100 200 300
mg trffILTB!fn/g charcoal
•400
' malachite groan
'mathylan* blua
' at frarln r«d
Figure 5. Adsorption of three dyes onto
tri fIuralin-amended charcoal.
These results suggest that it might be feasible to use methylene blue or
alizarin red dye to assess the remaining pesticide capacity of charcoal. A
possible scenario might have a pesticide user needing to filter 300 to 500
gallons of wastewater. Filtration of this waste could take a considerable amount
of time (18 to 24 h). To test the remaining adsorptive capacity of used, but not
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necessarily spent charcoal, the pesticide user would take a sample of charcoal
and add a known amount of dye dissolved in buffer solution. If any color remains
in solution after shaking the dye and charcoal together, the charcoal may not
have the capacity to remove pesticides from pesticide-laden wastewater. In this
case, the charcoal would be replaced, saving the operator valuable time by not
using charcoal with a diminished capacity to remove pesticides.
CONCLUSIONS
An activated charcoal filtration unit, fabricated using readily available
components, effectively removed the pesticides atrazine, benomyl, carbaryl,
fluometuron, metolachlor, and trifluralin from leftover pesticide solutions and
rinsates. Approximately 1500 L of wastewater could be effectively treated using
23 kg of Cullar-D activated charcoal before replacement was necessary. The
disposal of spent charcoal via microbial degradation is still under
investigation. Results from an alachlor incubation study suggest that this may
represent an alternative to incineration but more research is required to fully
determine the treatment's potential. The ability of methylene blue and alizarin
red dye to reflect differing amounts of adsorbed trifluralin on charcoal suggests
that these dyes could potentially be used as a rapid test to indicate when the
capacity of activated charcoal is exhausted and, therefore, when it is necessary
to replace the charcoal filter.
ACKNOWLEDGEMENTS
The authors gratefully acknowledge funding provided by the Cooperative
States Research Service and the Arkansas Water Resources Research Center. The
laboratory assistance of Mrs. Michelle Fitzgerald is also gratefully
acknowledged.
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LITERATURE CITED
Dennis, VI.H., Jr. 1988. A practical system to treat pesticide-laden wastewater.
In Pesticide Waste Disposal Technology, J.S. Bridges and C.R. Dempsey (eds).
Noyes Data Corp. 331 p.
Hassler, J.W. 1974. Purification with activated carbon. Chemical Publishing
Co., Inc. New York, NY. 390 p.
Humburg, N.E. 1989. Herbicide Handbook. Sixth Edition. Weed Sci. Soc. Amer.
Champaign, IL. 310 p.
Jury, W.A., Winer, A.M., Spencer, W.F., and D.D. Focht. 1987. Transport and
transformations of organic chemicals in the soil-air-water ecosystem. Rev.
Environ. Contam. Toxicol. 99:119-164.
Kilbane, J.J., Chatterjee, O.K., and A.M. Chakrabarty. 1983. Detoxification of
2,4,5-trichlorophenoyacetic acid from contaminated soil by Pseudomonas cepacia.
Appl. Environ. Microbiol. 45(5):1697-1700.
Miller, M.E. and M. Alexander. 1991. Kinetics of bacterial degradation of
benzylamine in a montmorillonite suspension. Environ. Sci. Technol.
25(2):240-245.
Mullins, D.E., Young, R.W., Palmer, C.P., Hamilton, R.L. and P.C. Sherertz.
1989. Disposal of concentrated solutions of diazinon using organic absorption
and chemical and microbial degradation. Pestic. Sci. 25:241-254.
Nye, J.C. 1988. Physical treatment options: Removal of chemicals from
wastewater by adsorption, filtration, and/or coagulation. In Pesticide Waste
Disposal Technology. J.S. Bridges and C.R. Dempsey (eds). Noyes Data Corp.
331 p.
Perrotti, A.E. and C.A. Rodman. 1974. Factors involved with biological
regeneration of activated charcoal. AIChE Symposium Series 144 vol.70, p. 316-
325.
Somich, C.J., Muldoon, M.T., and P.C. Kearney. 1990. On-site treatment of
pesticide waste and rinsate using ozone and biologically active soil. Environ.
Sci. Technol. 24(5):745-749.
Wolf, D.C. and J.O. Legg. 1984. Soil microbiology. In Isotopes and Radiation
in Agricultural Sciences, M.F. L'Annunziata and J.O. Legg, (eds). Academic
Press, New York. p.100-139.
Zanitsch, R.H. and M.H. Stenzel. 1978. Economics of granular activated carbon
water and wastewater treatment systems. In Carbon Adsorption Handbook. P.N.
Cherermisinoff and F. Ellerbusch, (eds). p. 215-239.
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Preliminary Studies of Batch Chemical Oxidation of
Wastewaters Containing Agrichemicals
By
Claude E. Breed and Michael C. Crim
Tennessee Valley Authority
National Fertilizer & Environmental Research Center
Chemical Development Department
Muscle Shoals, Alabama 35660-1010
ABSTRACT
The increased use of containment in the agribusiness industry has resulted
in improved control of contaminated wastewater but has also resulted in an
accumulation of wastewater that contains agrichemicals and cannot be easily
recycled or reused. TVA is currently investigating chemical oxidation methods
to decontaminate this wastewater. The major objective of the investigations have
been to develop procedures that can be carried out onsite using existing process
equipment. One approach tested was the use of strong acids and air sparging.
This resulted in air stripping of the volatile compounds and little oxidation.
A second approach has been to use hydrogen peroxide in the presence of a
catalyst. This method has resulted in a high level of destruction of the original
agrichemical but only about 80 percent destruction of the total organic carbon
(TOC) present. Future test work will be directed toward identification of the
remaining TOC and developing procedures to oxidize it.
TVA's National Fertilizer & Environmental Research Center (NFERC) is
actively engaged in environmental research work as part of its ongoing mission,
especially as it relates to environmental issues and problems which have an
impact on fertilizer manufacturers, dealers, and users. One such problem faces
more than 3,000 small dealers who custom mix fertilizers and pesticides for sale
to local farmers. After a dealer prepares a custom mix and transfers it to the
farmer, he often rinses his storage and mixing equipment so as to avoid
contamination of the next mix. This results in a volume of rinse water (rinsate)
containing a low-level pesticide contamination. Additional contaminated water
results from external equipment wash down and spills during transfer or storage.
In the past, dealers generally disposed of the contaminated water on his own
site, and this resulted in localized soil or ground water contamination from
repeated disposal. Currently, the main alternatives open for a dealer are to
field apply the contaminated water, reuse it in formulations of similar blends,
or in the worst case, to pay a waste disposal company to remove and treat the
waste rinsate.
NFERC initiated an applied research project with a narrow focus to
determine if a simplified, cost-effective method of destroying (or removing)
pesticides in rinsate solutions could be developed. A major objective was to
make the method simple enough that it could be carried out using process
equipment commonly available to the mix dealers. A secondary objective was to
tailor the decontamination process in such a way that the decontaminated solution
could be recycled, thus allowing the dealers to avoid the problems (and costs)
associated with effluent monitoring and reporting.
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The work was done in two main phases, the first being to test the use of
strong acids/heat/air to oxidize the pesticides. This work was followed by a
study of the use of chemicals and heat to oxidize the materials.
Strong Acids/Heat/Air Oxidation
The initial research test work focused on the possibility of using strong
acids, such as phosphoric, sulfuric, or nitric, to catalyze the oxidation of
pesticides by air in a batch system. This idea was appealing because of the
unique operating and marketing position of the fertilizer dealers. A dealer
would be able to take the process by-product solution, which now contains acid
from the decontamination process, and convert it to a usable fertilizer product
by ammoniation. In this way, the dealer could substantially recover the cost of
the acid. Potentially, the ammoniated acid solution could be used for blending
with other solutions or, if adjusted to a standard grade, sold directly to the
customer.
The test work was performed using synthetic waste rinsates containing one
of four commonly used herbicides: trifluralin, alachlor, metolachlor, and 2,40
amine. All synthetic rinsates used in the testing were produced by adding a
commercial-grade herbicide solution directly to tap water. The concentration of
the active ingredient was standardized to a level of 1,500 parts per million, a
level that is considered to be at the upper end of the range for dealer rinsates.
Since all of the commercial herbicides that were tested, except 2,40 amine,
contained an organic solvent, the concentration of total organic matter in the
synthetic rinsates varied among the different test pesticides.
Tests were made using each of the three strong acids (phosphoric, sulfuric,
and nitric) added directly to the synthetic rinsates. Combinations of these acids
were also tested. The test equipment was arranged so that the acid-dosed rinsate
could be pumped to a venturi mixer and returned to the batch holder. Air was
injected into the venturi to produce a turbulent contact between the two streams.
Most of the oxidation was expected to come from the oxygen in the air, rather
than donation of oxygen from the acid. Test solutions were heated to accelerate
the rate of oxidation. Test temperatures ranged from a low of 140«F up to a high
of about 190»F. Also included as part of the test work was the addition of
soluble trace metals, as suggested by the literature, to act as catalysts. The
catalytic metals were generally limited to those metals that are innocuous in
fertilizer solutions or are micronutrients, such as copper or iron.
The results of these tests were generally disappointing. In most cases,
the test herbicides were simply removed by air stripping in the venturi. The
least volatile herbicide, 2,40 amine, was essentially unaffected in these tests.
Some attempts were made to set up new equipment arrangements that would utilize
fixed-bed catalysts, instead of soluble catalysts. However, it was soon realized
that any such scheme would violate a core objective of the project—simplicity.
These efforts did, however, lead to the generation of an idea involving
three-phase batch oxidation.
Chemical/Heat Oxidation
The second phase of the bench-scale work involved the use of chemicals and
heat to oxidize pesticide contaminates. Two separate approaches were tested, the
first utilized a phosphoric acid, Mn02, and the second, Fenton's reagent (ferrous
ions in presence of peroxide). Results of these tests were encouraging.
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Phosphoric Acid - Mn02 Slurry: With this method, a solid, relatively
insoluble catalyst, manganese dioxide, was slurried by an agitator in a 2,4D
amine rinsate solution to which phosphoric acid had been added. The key to the
system was to operate the agitator at a sufficiently high rotational speed that
a deep vortex was produced. This created an intense three-phase mixing zone for
the air, manganese dioxide, and rinsate solution to come in contact with each
other. This method was able to effectively oxidize all of the test pesticide,
2,4D amine, within detection limits (about 10 ppm). However, about a quarter of
the original organic matter remained, as measured by a standard laboratory test,
total organic carbon (TOC). Since the 2,4D amine herbicide solution contains
only water as a solvent, it is assumed that the remaining organic matter existed
as fragments of the original herbicide. No attempt has been made to identify the
fragment compounds to date. However, it is clear from the total quantity of
oxidation that took place, that the molecular bonds in the chlorinated aromatic
rings of 2,4D amine were broken. This was considered a major hurdle in the
oxidation chemistry since these bonds are considered to be particularly oxidation
resistant.
A major drawback of this method is the potential energy cost. During the
lab experiments, nearly all of the water in the solution is evaporated due to the
large volume of air pulled into the solution by the agitator. This is also due,
in part, to the high operating temperature, 230°F, needed for oxidation to
proceed. (Note: The presence of phosphoric acid elevates the boiling point of
the solution to well above 230°F.) A second drawback to this method is that
those pesticides which are relatively volatile are likely to be evaporated before
oxidation can take place. This would probably mean that the off-gas from the
process would have to be treated in some manner, perhaps by incineration or
activated carbon recovery. Both of these methods would complicate the process
beyond the desired objective.
Fenton's Reagent: A method of liquid phase oxidation that is commonly used
in laboratory analytical chemistry is Fenton's reagent. This reagent, discovered
during the late 19th century, is a mixture of ferrous ions and hydrogen peroxide
that was observed to have enhanced ability to oxidize organic compounds. The
basis for this property is the initial reaction of peroxide with ferrous ions to
form ferric ions and hydroxyl radicals. The hydroxyl radicals react readily with
organic hydrogen by attacking carbon-hydrogen bonds. This attack in turn
facilitates direct oxidation of the organic compound by reaction with free
hydrogen peroxide.
Potentially, an adaptation of Fenton's reagent could meet all the project
objectives. It is simple enough to be applied in a single tank batch. The
oxidant, hydrogen peroxide, is relatively inexpensive compared with other
chemical oxidants. Furthermore, if the decontaminated solution is used in the
preparation of fertilizer mixes, then the catalyst, ferrous ion, becomes a
fertilizer micronutrient. Additionally, commercial sources of ferrous ion are
available in which the associated cationic species is also a nutrient (e.g.,
ferrous sulfate). Finally, since the literature suggests that Fenton's reagent
is more active under conditions of acidic pH, strong acids, such as phosphoric,
can be used that add nutrient value to the solution.
Test work was initiated to determine the parameter effects and the overall
effectiveness of Fenton's reagent when applied to synthetic rinsate solutions.
The herbicide 2,4D amine was again selected for the initial series of tests. All
test work was done using synthetic rinsates containing about 1,500 ppm by weight
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2,4D amine. Ferrous sulfate heptahydrate was chosen as the source of ferrous
ions. Phosphoric acid was used to adjust the pH of the test solutions in the
acid range, and potassium hydroxide was used for the basic range. Tests were
made using mild agitation and temperatures ranging from 120 to 180«F. Laboratory
grade 30% hydrogen peroxide solution was used in all tests.
Early tests focused on determining the overall effectiveness of the
Fenton's reagent method. Tests in which a large quantity of peroxide was used
(about 16 times the stoichiometric quantity needed to oxidize all of the organic
matter) and with a high temperature (180«F) produced very good results. As much
as 86% of the organic matter was oxidized in one of the tests. None of the
original 2,4D amine pesticide, within detectable limits, remained after
oxidation. In these early tests, ferrous ion content and pH were studied to
determine parameter effects. Both parameters exhibited plateau-shaped curves.
Organic destruction increased with increasing ferrous sulfate heptahydrate
addition up to a level of about 7 grams per liter, above which no further benefit
was found. Similarly, organic destruction increased with increasing pH up to a
level of around pH of 4, above which the effect was generally flat, even into the
basic range. This seemed to be somewhat contradictory to literature sources,
which suggested that acidic conditions were beneficial, and that a maximum effect
in most cases might be expected near a pH of 3.5. However, based on the test
results, pH adjustment was eliminated in subsequent testing. (Since ferrous
sulfate is slightly acidic, the unadjusted test solutions have an initial pH of
about 5.)
The follow-up test work with the Fenton's reagent has focused on two
related objectives: (1) increasing the percentage of total organic matter that
is oxidized during the process, and (2) reducing the quantity of hydrogen
peroxide required by the process. The first objective, increasing oxidation
percentage, has not been achieved in subsequent tests. It appears that a
destruction level of 85 to 88% was a barrier for Fenton's reagent when applied
to 2,4D amine. Longer retention times, and even repeated applications of
Fenton's reagent to the same solution, were unable to increase the quantity of
organic matter destroyed. It appears that in future tests of 2,4D amine and all
other pesticides which exhibit similar oxidation resistance, the organic
compounds which remain after oxidation must be identified by qualitative
analysis. If these compounds are innocuous, then the decontaminated solution may
be reuseable as make-up water for fresh fertilizer/pesticide mixes. If not, then
clearly, additional treatment steps will be required. At this point in the
research work, this is a major problem to be identified.
Modest improvements were made during the study of the second objective,
reducing hydrogen peroxide usage. By adding a small amount of copper (II)
sulfate to the solution as a supplemental catalyst, the hydrogen peroxide usage
was cut in half, from 16 times stoichiometric to 8 times stoichiometric, while
still maintaining the maximum organic destruction level of 85 to 88%. In terms
of commercial scale volumes, the quantity of 30% hydrogen peroxide solution was
lowered from 23 gallons per 100 gallons of rinsate to 11.5 gallons.
A further reduction of hydrogen peroxide is desirable. In a commercial
process, the cost of hydrogen peroxide will be the major operating cost. At the
minimum peroxide requirement stated above, the peroxide cost will be
approximately $32 per 100 gallons of rinsate.
98
-------
Conclusions from Preliminary Test Work
The results of this preliminary test work has shown the use for a
simplified approach to the onsite treatment of contaminated rinsewater is
feasible. Depending on the composition of some of the residual degradation
compounds, the proposed process based on Fenton's reagent appears to be the most
promising approach tested to date. Other treatment schemes will be considered
in future work and the most attractive process will be carried to pilot and/or
demonstration scale.
99
-------
; V -> i S i
',"' , I 'jj
(7 p--,
V' ><„ !
"-'- •'..- ! !-P
I',". i;.:.n
.-.,.• C5jd
!•'•; :.;'e:
, (1 • P £•
-------
by varying the temperature and/or the pressure such that the density of the fluid
can approach that of typical liquid solvents. For example, at 50oC and 68 bar
(1000 psi) C02 has a density of 0.2 g/mL, at 120 bar (1760 psi) the density is
0.6 g/mL, ana at 214 bar (3150 psi) the density is 0.8 g/mL. If a constant
temperature is maintained and the pressure is increased sufficiently the density
will approach the liquid density. The density of liquid C02 is 1.101 at -37oC
(1). At its critical point (Tc = 31°C, PC = 73 bar) C02 has a density of 0.46
g/mL (3).
The unique characteristic of supercritical fluid extraction (SCFE) is that
an SCF remains in a gaseous state and as such can penetrate the interstitial
spaces of solid materials much more readily than liquids. This allows the SCF
to make intimate contact with any substance that is sorbed to the solid material
and facilitates the removal of contaminating materials. Figure 2 shows the self-
diffusivity of C02 over a wide temperature-pressure range and, for comparative
purposes, the range of diffusivities for solutes in organic liquids ((average of
about 10"5 cm2/sec (4)). With changes in temperature and pressure an SCF can be
tailored to extract substances that are difficult, if not impossible, to separate
by other means. Supercritical C02 is a nonpolar solvent, and a good rule of
thumb is that most compounds that are soluble in hexane will also be soluble in
supercritical C02. However, the extraction characteristics may be changed to
make the extraction fluid more polar by adding enhancers such as methanol or
acetone to the system.
Another interesting characteristic of SCFs is that shown in Figure 3 (5).
The figure shows the solubility of naphthalene (wt. %) in supercritical C02 with
varying temperature and constant pressures. The diagram shows that at lower
pressures the solubility increases with increasing temperature but at some point
the solubility begins to decrease with an increase in temperature. However, at
about 150 atmospheres and higher, the solubility continues to increase with an
increase in temperature. If the temperature is increased sufficiently, the
solubility will probably again begin to decrease. This is because the SCF
becomes more like a gas than a liquid and, as such, has much less solvating
power. The dashed line represents the solubility of naphthalene in liquid C02.
Figure 4 (6) shows similar behavior for the solubility of Si02 in water, and it
is suspected that this behavior will exist for all solutes in SCFs.
The following equation of state was taken from an English translation of
the Russian text Thermophysical Properties of Carbon Dioxide (7).
The expanded form of the equation of state for gaseous C02 may be written as:
PV/RT = 1 + (Bd + Cd2 + Dd3 + Ed4 + Fd6 + Gd8) where
B = 0.486590(i+97/96+T)~[(l.90843+5.351ea)A]-(0.079526/T8)
C = 2.39169-[(6.9619-12.1824ea)/-r] + (6.86903/T2)-(3.34265/i3)
D = -1.69007+[(10.2469-6.38963ea)A]-(14.7337/T2) + (7.32711/-u3)
E1 = 8.69339-(16.9642/t)+(8.92312/T3)
E2 = -2.40368+(6.61817/t)+(9.92898/T2)-(36.4789/T3)+(22.0167A4)
F, = -37.3064+(102.476/T-6737594A2)
101
-------
-------
'.,< ' ' • ,0 JtUfllj j
>»'• ! .) , .iiHlltUlSU]
p'lii i r Kjn . M ( [PAOIIIO.I
-------
Wt. % in soil
Wt. % in soil
Atrazine Alachlor
3.6
8.9
Bentazon
11.9
Permethrin
10.2
after ext.
Wt. % removed
0.06
98.3
0.18
97.9
0.59
95.0
0.21
97.9
The use of SCFE in remediating sites contaminated with various organic
compounds is currently under consideration by EPA's Superfund Innovative
Technology Evaluation (SITE) program. Other laboratories (outside TVA) have
indicated that
and toxaphene
from contaminated soils,
that no difference in overall
from dry soil and wet soil.
supercritical C02 readily extracts compounds such as PCBs, DDT,
Initial work by Brady et al. (9)
of 70-90% for these compounds and found
extractability existed between contaminant removal
demonstrated C02 extraction efficiencies
CONCLUSIONS
SCFE should be applicable to remediation of contaminated soil. There are
both advantages and disadvantages to using supercritical C02. The advantages
include: 1) CO, is non-polluting, 2) C02 is relatively inexpensive, 3) material
can be recycled*^ if enough is extracted, and 4) it should be possible to build a
portable unit that can be moved from site to site without problems associated
with interstate regulations because no hazardous materials are transported.
Disadvantages include: 1) relatively high pressures needed, 2) all contaminants
may not be extracted with one set of conditions, and 3) the contaminants are not
destroyed. However, because the volume of contaminated material is reduced
considerably, a small secondary treatment unit such as incineration, ultraviolet
ozonation, or chemical reduction could be added to the system. Incineration may
be the most readily adaptable, if local regulations do not prohibit it.
104
-------
REFERENCES
1. Hannay, J. B. and J. Hogarth, "On the Solubility of Solids in
Gases," Proc. R. Soc. London, 1879, 29, 324.
2. CRC Handbook of Chemistry and Physics, 67th Ed, 1986-1987.
3. Perry's Handbook for Chemical Engineers, 5th Ed.
4. Paulaitis, M. E., Krukronis, V. J., Kurnik, R. T., and Reid, R. C.,
"Supercritical Fluid Extraction," 1983a, Ber. Bunsenges. Phys. Chem., 88,
869.
5. Modell, M., Robey, V. J., Krukonis, V. J., de Fillipi, R. D., and
Oestereich, D., "Supercritical Fluid Regeneration of Activated Carbon."
Paper presented at the National AIChE Meeting, Boston, MA, 1979.
6. Kennedy, G. C., "A Portion of the System Silica-Water," Econ. Geol., 1950,
45, 629.
7. Vulkalovich, M. P. and Altunin, V. V., Thermophysical Properties of Carbon
Dioxide, translation edited by Dr. D. S. Gaunt, Kings College London,
published by London & Wellington, 1968.
8. Viorica Lopez-Avila and N. S. Dodhiwala, Journal of Chromatographic
Science, "Supercritical Fluid Extraction and Its Application to
Environmental Analysis," 1990, 28, 468-476.
9. Brady et al., "Supercritical Extraction of Toxic Organics from Soils,"
Ind. Eng. Chem. Res., 1987, 26, 261-268.
105
-------
m
a:
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PRESSURE
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LL
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CRITICAL POINT
10
70
80
100
150
200
SATURATED
L I QUI D
TYPICAL DIFFUSIVITIES OF SOLUTES
IN NORMAL LIQUIDS
20 40 60
TEMPERATURE C CJ
80
lao
Figure 2 Diffusivity behavior of CO
107
-------
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details in multiple sizes. Kammel and O'Neil (1990) reported on a farm sized
concrete loading pad that meets many small facility needs.
STANDARDIZED MODULAR CONCRETE PAD DESIGN
Modular concrete mixing/loading/storage containment pad designs are needed
to fit individual operator requirements. Standardized pad designs can be used
by aerial and ground pesticide applicators using 1,100 to 1,900 liter (300-500
gallon) rinsate tanks, pesticide mini-bulk or small volume returnable (SVR)
containers, non-returnable containers, and a range of pesticide or liquid
fertilizer bulk tank sizes.
DESIGN OBJECTIVES
Modular design objectives are to:
1. Develop a simple, modular concrete pad design suitable for mixing/loading
and rinsing aerial or ground pesticide and liquid fertilizer sprayers.
2. Develop watertight reinforced concrete specifications to resist ground and
weather stress, and chemical or mechanical damage.
3. Design shallow watertight sumps that can resist ground and weather stress
cracks, and can be easily cleaned.
4. Provide secondary containment for pesticide and liquid fertilizer leaks
and spills.
5. Incorporate areas for pesticide and liquid fertilizer and rinsate storage,
handling, mixing, transfer, recovery, and disposal.
FUNCTIONAL PAD LAYOUT AND USE
Agrichemical facility management functions should be the first item
addressed in planning new or remodeled facilities areas and functions should
include the following:
• Chemical Storage • Mixing/Loading • Secondary Containment
• Loading Pad • Worker Safety • Rinsate/Waste Disposal
• Pesticide Security • Storm Water Control • Tanking Mounting/Plumbing
Chemical Storage
Pesticides should be stored in a building for protection from theft,
vandalism, temperature extremes and unauthorized personnel. It should be used
only for pesticides and be isolated from other buildings. Warning signs
indicating dangerous toxic materials must be posted outside by all building or
fence entrances. Buildings should be ventilated to prevent an accumulation of
toxic fumes. Figure 1 shows the arrangement of functional areas in a farm or
small business-sized pesticide facility. Figures 2 and 3 illustrate plan and
cross section details of this same facility. Specifications for a small storage
112
-------
bui 1 a i "iq d,'-.> ^
'•'
i;': i o n . i iduiu can be used
j1 >;;• . '- ;fci to transfer
' :r'= 1' (Q 1} or in
1 • ;;r,-:if:r pumps should
', ' .V! n'ixinq tanks
. ' - ••••v.-nt. provides
,• ••-•• 'c "'oading areas.
>' •» i : i : .<• e r
or' pest.c : i ,
t>on? 1 e.-.t.h .
f er* i ' ~;2fir
!.ito three
icid? mixing,
HXi covered,
sir^age tank
r -vtorn. plus
hd-i d SCUf" ''">•'"" .ii S'd 'I 1 •:;'.(, ri
tank r i'Vi -4 if; ; s ,/:;H\! 4 • - .-,
Sprayer eu1: i'.'>.r •: n. .,••((.-.,'-,•,•,•. c -;
COMed 't-.jf"; 0>- u?ip> f-u.,; ;;
surf axe '<-. •-.!':?.) t-u *:o ^ .^h-i < :c-v.
spiiis, w.iLi.'i ru,.;' '/'"• :.;.,", '
U50 -J S "••', -'(. , '•„..!..""'" '. ' '
••'. us^o' to park equipment
.r'x^r facility, (Figure 4)
es. Sprayer plumbing and
I - p« containment area.
hi; a ine on this area to
iHp curbec concrete pad
..-v-;v; ^ater from leaks or
' ' i'.*.: .,f,o^;;qe tanks for
A s'oi'^t* i«t*.;y .J/'^-!
first- aid tu v.'orkers. An e'
cherpif.a's f ro^ the eys.s, ^-.,,
a/ara for MaerrjGiicy et^si^in
be easily .-;;:( ^^s ihlt? to '!e^
safety data >»!e..n/> (MSDS/ '
posted -':;;f - ;;
c. tonne •-!,?' of or N,- Icirn:.
o>-
u'iq p.{\: innr-,"!. Mviuid oe equipped for
should be provided to rinse
equipment should trigger an
.•1-1 ?r-o -.^piil iespon:,e kits should also
c._(. i'lf-i-ts or. .-> ••,)';•!?]v marine-•". Material
; '\::, .,?.<;»•-o .i: i:'-3 facility should be
.•').;"'•-.:• »r emergency sise. A fire
^i L".«i oocitioned outside
-------
Rinsate/Waste Disposal
Rinsate is segregated by crop or pesticide and reused on the target crop,
eliminating disposal as hazardous waste. If the loading pad is not roofed,
rainwater falling on the pad is collected and stored for future use, if there has
been a spill. If the pad is clean, rainwater may be pumped off the pad. To
eliminate contaminated solids disposal problems, exterior washing of ground
applicators should be done at the application site immediately after each
operation.
Pesticide Security
Chemical and rinsate storage containment areas should be secured by heavy
chain-link fencing (Figure 4) or be inside a locked building. Fencing mounted
flush with the outer containment wall should be at least 1.8 meters (6 feet) of
combined height. Fencing not flush wall mounted (with a concrete ledge) should
extend 1.8 meters (6 feet) above concrete walls. Containment section widths
(Figures 4 and 8) can be sized for the installation of pesticide storage
buildings, such as the OSU (1983) pesticide building, Midwest Plans Service
(1979) storage building or other suitable structures.
Empty disposable containers should be stored on a covered, curbed area to
prevent rain entry into containers or leaks from containers contaminating the
soil. Empty minibulk or Small Volume Returnable (SVR) containers should also be
stored in this area.
Storm Water Control
Divider walls separating loading from containment areas, Figures 5, 6, and
7, have no openings. Spills, leakage, or stored rinsate can not be discharged
into surface water channels without pumping. Sumps should be formed using coned
bottom cylindrical stainless steel sump liners cast in-place with the liner used
as the inside concrete form for ease of cleanout.
Tank Mounting and Plumbing
Rinsate tanks should be elevated at least 8-15 centimeters (3-6 inches)
above concrete floors for quick leak identification. Tanks must be anchored to
prevent overturning and plumbed with flexible hoses between tanks to avoid pipe
ruptures from floatation of partially filled, improperly anchored tanks during
major leakage events or rain storms. Transfer hoses should be marked by crop or
chemical for positive I.D. of tank and product to eliminate cross-contamination.
LIQUID FERTILIZER CONTAINMENT
The major problem in designing containment sections is determining the best
combination of containment area and wall height (CVD + liquid freeboard) to
provide the 125% of volume of the largest tank. The area displaced by all tanks,
including the area of the largest tank, plus any equipment in the containment
area must be added to the net fluid volume that can be released by the largest
tank when the liquid level stabilizes. The volume of fluid remaining in the
largest tank at the liquid level equilibrium height must be subtracted from the
total tank volume in the computation, Equation 1.
114
-------
The containment holding volume should be designed to provide a minimum of
"125% of largest tank" for pesticide, rinsate, or liquid fertilizer tank
containment to provide inches of liquid level freeboard. Rinsate tank management
systems normally are operated with 3 to 6 tanks ranging from 300 to 500 gallons
each. If small to moderate sized liquid fertilizer tanks, ranging from 5,000 to
25,000 gallons are planned for use with this pad design, containment section
widths and sidewall heights need to be sized to accommodate the required 125%
volume of largest tank. Some states use 110% of largest tank plus a 6" rain as
their containment volume regulation design.
The use of very large liquid tanks (50,000 - 1,000,000 gallons) is outside
the scope of this paper. These tanks require development of special containment
pads and foundations due to their size. They may be incorporated into the main
concrete pad containment, or be designed as individual structures with their own
containment areas separate from the wash pad and pesticide tank containment area.
Design guidance by Midwest Plan Service (1983) for circular concrete tanks may
be helpful for large tank foundation designs.
Some state laws allow non-concrete containment designs for large liquid
fertilizer tank installations. One design uses flexible liners, either a 36 or
45 mil thickness DuPont Hypalon, laid on a sand sub-base with 6 inches of clean
smooth washed river run gravel as ballast. Liners are placed over soil berms,
concrete outer walls (padded on the inside), or special composite plastic
structural walls. Some states allow compacted clay or other impervious soil
lined containment; the risk of having to dispose of contaminated soil after a
leak or spill makes this option a high risk.
NOTE: The total containment volume must be reduced bv the volumes displaced
by tanks and equipment that take UP containment space. Pesticide rinsate should
not be stored in the same containment section with fertilizers. Fertilizers must
not be stored 1n the same containment section with full strength pesticides. BY
LAW!
DESIGN LAYOUT CONSIDERATIONS
NOTE! It is extremely Important to do scale drawing layout of the area
with the tanks drawn to scale in position, as the 125% of largest tank provides
minimum area when depths of 3 ft. or more or used.
Functional Layout Questions:
(1) Is there adequate space for present and future tanks plus mixing and
transfer equipment in the proposed containment area?
(2) Will the area be adequate for potential growth and can small
existing tanks be replaced by larger tanks in the future?
(3) From a safety standpoint, can workers move between tanks with hoses
and move over containment walls without undue risk or hazards?
(4) Will safety steps and handrails be required to move over walls, and
if so, will this be a continual problem for workers, especially in
icy weather?
(5) Can all outside surfaces of all tanks be visually inspected for
corrosion, damage and potential leaks?
(6) Are tanks securely anchored individually or braced together to
prevent floatation, tipping over, and damage to other tanks.
115
-------
(7) Are tanks plumbed individually or with flexible plumbing connections
to avoid plumbing damage and multiple leaks from tank floatation (No
rigid pipe manifolds connecting tanks).
These questions should all be answered "YES" when the layout design is
checked for tank fit and completed and the wash/containment layout plan is
submitted to the appropriate state regulatory agency.
In general, a 30 to 36 inch containment section depth (27-33 inch CVD + 3
inch freeboard) appears to be the most practical, although it may be slightly
more expensive than a deeper section. If a deeper section is selected, "wide
steps on both sides of the wall at security fence gate openings must be provided
for personnel safety, comfort, and convenience,
Table 5 gives volume data tank sizes from 5 ft. to 15 ft. diameter for
heights to 20 ft. Volume for additional heights can be computed by selecting the
volume at the additional incremental depths used for heights above maximum table
values and adding the two values together, Tank base areas are needed in
computing the total tank area displaced.
CONTAINMENT VOLUME SIZING
Containment volume and liquid freeboard must provide at least 125% of
volume of the largest tank. The area displaced by other tanks, plus any
equipment in the containment area must be aaded to the net secondary fluid
containment volume (SCV) that can be released by the largest tank when the liquid
level stabilizes.
The secondary containment volume can be computed for 125% of the largest
tank by using Equation 1:
EQUATION 1.
SCV = LTV x 1.25 + TBV (METRIC) or SCV
1000
LTV x 1.25 + TBV (ENGLISH)
7.5
EQUATION 2:
CFA « SCV/CVD
Where:
SCV =
LTV =
CFA =
CVD =
1.25 =
1000 =
[7.5] =
TBV =
Secondary Containment Volume, Cubic Meters. [Cubic Feet]
Largest Tank Volume, Liters [Gallons]
Total Containment Floor Area, Square Meters. [Square Feet]
Containment Volume Depth, meters [Ft.] (Total Average
Liquid Depth Plus Freeboard Depth)
125% of Largest Tank Leakage (Provides Freeboard)
Liters of Liquid per Cubic meter
[Gallons of Liquid per Cubic foot]
Sum of Tank Base Volumes, Cubic Meters [Cubic Feet] (Does
not Include Largest Tank as Some Liquid Remains in the
Tank.)
116
-------
NOTE: The volume of fluid remaining in the largest tank at the liquid
level equilibrium height must be subtracted from the total tank volume in the
computation. The total containment volume must include the volumes displaced bv
tanks and equipment that take up containment space. Once the approximate wall
height or depth of the containment section is selected, and the secondary
containment volume (SCV) is determined, the floor area can be calculated. The
total containment floor area (CFA) is computed from Equation 2.
For states that use 100% of largest tank plus a 24 hour 25-year storm
instead of 125% of the largest tank, use 1.00 (100%) in place of 1.25 (125%) and
add the predicted volume of water that falls on the containment area. REMEMBER:
All tank bases displace water, so a 6 inch rainfall may raise containment level
by 9-12 inches, if 25% to 50% of the volume is taken up by tanks.
EXAMPLE: A liquid fertilizer dealer has 2 - 12 ft. x 20 ft., 3 - 10 ft.
x 15 ft., and 2 - 9 ft. x 15 ft. vertical storage tanks that must be contained.
He is concerned with building an economical containment section as part of his
new applicator load pad and his bulk truck unloading safety pad. He is trying
to decide between a 3 ft. 3 in. and a 4 ft. 3 in. containment depth. These
depths will provide a 3 inch freeboard depth plus average containment volume
depth (CVD).
He first needs to calculate the Net Containment Volume, NCV for each of the
two containment section depths, Table 7.
For 3 ft., NCV = (LTV - GPF x CVD) x 1.25 = (16.690 - 848 x 3) x 1.25 -
7.5 7.5
- (16.960 - 2.544) x 1.25 = 2,402 cu. ft.
7.5
At 3 ft. depth, the floor area
covered by the leaking liquid = 2,402/3 = 801 sq. ft.
For 4 ft.,
NCV = (16.960 - 848 x 4) x 1.25 - H6.960 - 3.392) x 1.25 - 2,261 cu. ft
7.5 7.5
At 4 ft. depth, the floor area covered by - 2,261/4 = 565 sq. ft.
Equipment area or displacement volume of transfer pumps is usually
insignificant and will be ignored in this example. If large mixing tanks and
transfer tanks or pesticide rinsate containment tanks are to be placed in the
containment area, their displacement area and volume must be included.
The floor area displaced by all tanks, including the "leaking" tank is 2
x 113.1 (12 ft. tanks) + 3 x 78.5 (10 ft. tanks) + 2 x 63.6 ( 9 ft. tanks) -
226.2 + 235.5 + 127.2 = 588.9 or 589 sq. ft. The total containment section floor
area for a 3 ft. depth - total liquid displacement area + total tank and
equipment area = 801 + 589 = 1,390 sq. ft. For the 4 ft. depth, the total area
= 565 + 589 = 1,154 sq. ft. A 23 ft. x 60 ft. or 28 ft. x 50 ft area would
117
-------
Competition causes significant price differences, even within a 30 to 50
mile radius. For example, in central Oklahoma a 6 or 7 bag Type IIA concrete mix
will cost about $45-50 per cubic yard. In central Indiana in an area with little
or no competition, prices run $55-60 per cu, yd. Type II cement normally costs
$2-5 per cubic yard more than Type I cement. A 45' x 70' pad of this design
installed at an aerial applicator site in North Eastern Idaho in November, 1989,
had delivered concrete costs of $46.00/cu. yd. Today, this cost would run about
$50-52/cu. yd.
Table 4 lists estimated prices for components and services needed to
construct the modular concrete pad designs shown in Figures 4-6 and Table 1, for
6.0 and 7.0 bag mixes. From Table 2, the cement volume required is basically a
function of the maximum aggregate size selected. With 1.0 inch to 1.5 inch
aggregate, a 5.5 or 6.0 bag/cubic yard mix should provide equivalent strength to
a 7.0 bag mix using 1/2 inch aggregate for approximately 4,000-4,500 psi
compressive strength concrete.
Forming labor and finishing labor usually quoted on a cost/sq. ft. basis.
Some concrete contractors combine forming and finishing quotes at slightly lower
costs. Typical forming costs range from $.20 to .30/sq. ft.; finish costs range
from $.25 to .35/sq. ft. Total forming placement and finishing costs range from
$.45 to .65/sq. ft. These costs may increase by 30-50% in some high labor cost
areas. The differences in total cost for 6.0 bag versus 7.0 bag mixes amounts
to about $5.00-$7.00/cu. yd. finished, or about, 5% added cost for a 7.0 bag mix.
NOTE: The cost estimates in Table 4 are based on constructing new concrete
pads on bare undisturbed earth within the base zone of the concrete plant, when
no unusual construction problems are encountered. No security fences and gates,
rinsate tanks, pumps, plumbing, electrical wiring, buildings, or approach ramps
are included.
Concrete pad costs vary significantly with geographic location,
availability and competitive costs of concrete and concrete readimix plant
location from the construction site. Total pad costs as a ratio of delivered
concrete costs typically range from about 2.5 to 3.0 X (where ground is level and
clear -- minimum earthwork). If substantial earthwork or reconstruction is
required, costs may run 3.5 to 4.5 X delivered concrete costs. At a ratio of 3.0
for $50/cu. yd. concrete, total finished cost would be 3.0 X $50/cu. yd. = $150
cu. yd. At that rate, a 50' x 65', 68 cu. yd. pad would cost $10,200. With
substantial site preparation or removal of an existing structure was involved at
a remote site, the cost for this size pad may be $13,000 to $15,000.
FUTURE DESIGN ASSISTANCE
Standardized concrete wash and containment pad designs for aerial and
ground agricultural chemical applicators in the U.S. are now being developed by
the authors of MWPS-37, "Fertilizer and Pesticide Facilities Handbook" for
Midwest Plan Service, Ames, IA and Tennessee Valley Authority (TVA) for Summer
1991 publication. More construction cost, structural design and tank volumes vs.
containment pad size and shape detail on the commercial pads can be obtained by
requesting the technical paper by Noyes and Kammel (1989), and on the farm pads
by contacting Kammel and O'Neil (1990).
120
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REFERENCES
Concrete Sealers for Protection of Bridge Structures, 1981. National Cooperative
Highway Research Program Report 244, Iransportation Research Board, National
Research Council, Washington, D.C., 12/81, 138p.
Effects of Substances on Concrete and Guide tc Protective Surfaces, 1986. PCA
Bulletin IS001.067, Portland Cement Association, Skokie, IL, 21p.
Gilding, T. J. (Editor), 1988. "Managing Pesticide Wastes: Recommendations for
Action", Summary of National Conferences and Workshops on Pesticide Waste
Disposal, National Agricultural Chemical Association, Washington, D.C., July,
1988, 85p.
Hirsch, Itzhak, 1986. "Chemical Waste Management at Agricultural Airstrips", ASAE
Paper No. AA86-002, Chimav Services, Herzliya Airport, Israel, NAAA/ASAE Joint
Technical Session, Acapulco, Mexico, 9p.
Hofman, V, and J. Gardner, 1989. "SAFE Storage, Handling and Disposal of
Pesticides and Containers", Fact Sheet AE-977, Cooperative Extension Service,
North Dakota State University, 4p.
Isaacson, Lief, 1989. Personal Telephone Conversation from Terraton, Idaho,
November 18, 1989.
Joint Design for Concrete Highway and Street Pavements, 1975. PCA Bulletin
IS059.03P, Portland Cement Association, Skokie, IL, 13p.
Kammel, D. W., 1988. "Protective Treatments for Concrete", Agricultural
Engineering Department, University of Wisconsin, Madison, WI, February, 1988, 7p.
Kammel, D. W., 1989. "Protective Treatment Companies", Agricultural Engineering
Department, University of Wisconsin, Madison, WI, January, 1989, 3p.
Kammel, D. W. and D. O'Neil, 1990, "Farm Sized Mixing/Loading Pad and
Agrichemical Storage Facility", American Society of Agricultural Engineers Summer
Meeting, Columbus, OH, June, 14p.
Kearney, P.C., M.T. Muldoon, and C.J. Somich, 1987. "A Simple System for
Decomposing Pesticide Wastewater", Pesticide Degradation Laboratory, ARS, USDA,
Beltsville, MD. Presented to Division of Environmental Chemistry, American
Chemical Society, New Orleans, LA, August 30, 1987, 4p.
Noyes, R. T., 1988-A. "Modular Concrete Pad Facility for Pesticide Waste
Management", Aerial Agricultural Association of Australia, Ltd., Convention 88,
Coolangatta, Queensland, Australia, May 30-June 1, 1988, 22p.
Noyes, R. T., 1988-B. "Modular Concrete Chemical Handling Pad Facility", 1988
NAAA/ASAE Joint Technical Session, Las Vegas, NV, 25p.
Noyes, R. T., 1989-A. "Modular Concrete Chemical & Liquid Fertilizer Handling
Pad Facility", Agricultural Engineering Department, Oklahoma State University,
January, 32 p.
121
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Noyes, R. T., 1989-B. "Modular Farm Sized Concrete Agricultural Chemical
Handling Pads", Agricultural Engineering Department, Oklahoma State University,
February, 25 p.
Noyes, R. T. and D. W. Kammel, 1989. "Modular Concrete Wash/Containment Pad For
Agricultural Chemicals", American Society of Agricultural Engineers Winter
Meeting, New Orleans, LA, December, 32p.
"Pesticide Storage Building, 1983. Plan no. Ex. 6346, Cooperative Extension
Service, Oklahoma State University, Ip.
"Pesticide Storage and Mixing Building", 1979. Plan No. MWPS-74002, Midwest Plan
Service, Ames, IA, 4p.
Powers, T.C., Durability of Concrete, ACI Publication SP-47, American Concrete
Institute, Detroit, 9p.
Rester, Darryl, 1986. Waste Water Recycling, Paper No. AA86-001, 1986 Joint
Technical Session of National Agricultural Aviation Association and American
Society of Agricultural Engineers, Acapulco, Mexico, December, 1986, 11 p.
Rester, Darryl, 1984. Aircraft Washwater Recycling System, Drawing No. 26-01,
Sheet 1 of 1, Louisiana State University, Cooperative Extension Service,
September 1984.
Thickness Design for Concrete Highway and Street Pavements, 1984. PCA Engineering
Bulletin EB109.01P, Portland Cement Association, Skokie, IL, 47p.
Watertight Concrete, 1975. PCA Bulletin IS002.03T, Portland Cement Association,
Skokie, IL, 4p.
122
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Table 1. CONCRETE PAD DIMENSIONS
to
Dimension"
A
B
C
D
E
F
G
H
'I
J
K
L
M
N
0
P
Q
R
S
T
"U
V
M
X,
X,
Y,
t,
NOTES:
6.1x9.1 (20x30)
6.10 ii (20'-0")
3.05 M (10'-0")
9.H M (30'-0»)
6.10 • (20'-0")
3.05 HI (10'-0»)
35.56 cm (14")
35.56 cm )
2.13 m (71)
2839 L (750 Gal.)
54.61 cm (21 1/2")
49.53 cm (19 1/2")
60.96 cm (24")
50.48 cm (19 7/8")
66.04 cm (26")
55.56 cm (21 7/8")
9.1x12.2 (30x40)
9.14 m (30'-0")
3.05 m (10'-0")
12.19 m (40'-0»)
9.14 m (30'-0")
4.57 m (15'-0»)
43.18 cm (17")
43.18 cm (17»)
53.34 cm (21")
0 cm (0")
27.94 cm (11")
17.78 cm (7")
27.94 cm (11")
45.72 cm (18")
76.20 cm (30»)
5.08 cm (2")
12.70 cm (5.0»)
3.OX
0.95 cm (3/8")
3.05 m (10')
3.05 m (10')
5678 L (1500 Gal.)
85.09 cm (33 1/2")
80.01 cm (31 1/2")
91.44 cm (36")
80.96 cm (31 7/8")
96.52 cm (38")
86.04 cm (33 7/8")
Pad Site m x m (ft x ft)
12.2x16.8 (40x55) 15.2x21.3 (50x70)
18.3x24.4 (60x80) 24.4x33.5 (80x110)
12.19 m (40'-0")
4.57 m (15'-0")
16.76 m (55'-0")
12.19 m (40'-0»)
6.10 m (20'-0")
45.72 cm (18»)
45.72 cm (18»)
58.42 cm (23")
0 cm (0")
30.48 cm (12")
17.78 cm (7»)
30.48 cm (12")
45.72 cm (18")
76.20 cm (30")
5.08 cm (2")
12.70 cm (5.0")
2.5X
0.95 cm (3/8»)
3.96 m (13*)
3.96 m(13>)
12924 L (3415 Gal.)
85.09 cm (33 1/2")
80.01 cm (31 1/2")
91.44 cm (36")
80.96 cm (31 7/8")
96.52 cm (38»)
86.04 cm (33 7/8")
15.24 • (50--0")
6.10 m (20'-0")
21.3 m (70'-0")
15.24 m (50'-0")
7.62 m (25'-0")
45.72 cm (18")
53.34 cm (21")
68.58 cm (27")
0 cm(0")
38.10 cm (15")
22.86 cm (9")
38.10 cm (15")
45.72 cm (18")
76.20 cm (30")
5.08 cm (2")
13.97 cm (5.5")
2.5X
1.27 cm (1/2»)
3.96 m (13')
3.96 m (13')
27303 L (7215 Gal.)
85.09 cm (33 1/2")
80.10 cm (31 1/2")
91.44 cm (36")
80.96 cm (31 7/8")
96.52 cm (38")
86.04 cm (33 7/8")
18.29 m(60'-0")
6.10 m(20'-0")
24.38 m(80'-0")
18.29 m(60'-0")
9.14 m(30'-0")
45.72 cm (18»)
60.96 cm (24")
78.74 cm (31»)
0 cm (0")
45.72 cm (18")
27.94 cm (11»)
45.72 cm (18")
45.72 cm (18")
76.20 cm (30")
76.20 cm (30")
13.97cm (5.5")
2.5X
1.27 cm (1/2")
4.57 m (15')
4.57 m (15')
39612 L(10465 Gal.)
85.09cm (33 1/2")
80.01cm (31 1/2")
91.44 cm (36")
80.96cm (31 7/8")
96.52 cm (38")
86.04cm (33 7/8")
24.38 • (80'-0")
9.15 m (30'-0")
33.53 m (110'-0">
24.38 m (80'-0")
12.19 m (40'-0")
60.96 cm (24")
76.20 cm (30")
96.52 cm (38")
0 cm (0")
60.96 cm (24")
40.64 cm (16")
60.96 cm (24")
45.72 cm (18")
76.20 cm (30")
76.20 cm (30»)
15.24 cm (6.0»)
2.5X
1.27 cm (1/2")
3.96 m (13')
3.96 m (13*)
110230 L(29125 Gal.)
85.09 cm(33 1/2")
80.01 cm(31 1/2")
91.44 cm (36")
80.96 cm (31 7/8")
96.52 cm (38")
86.04 cm(33 7/8")
If "I" is changed, add the new "I" value
"I" can be increased to provide Increased containment volt
to ''G"."H","J" and "K" dimensions.
"U"= Total Containment Section Volume, Gallons; Displacement Volume of tanks, and equipment must be
subtracted to determine Net Usable Volume to meet EPA requirements.
See Figures 2-8 for letter designation
-------
Table 2. WATERTIGHT CONCRETE MIX DESIGNS APPROXIMATE VALUES
Mdx. Coarse
Aggregate Size
cm /(Inches;
i
Kg!L)/n'
0 4C;" 04V"
Lbs (Gals }/yd'
0 40!" 0.45"'
% By
Volume
134/134!
109(109}
200(24) 22
-------
Table 3. CONCRETE AND STEEL COMPONENT ESTIMATES
•vj
LT!
Pad Size Concrete (1)
U x L
Reinforcing Steel (2)
Total Volume Pad Thickness Beinf. Steel Size
B x a (ft x Ft) cu. • (C*j. Tcfa;
fc ',-5.1
o '..» 12.
U' /V '!•>
15. ;>.,.!.
<8.i<-,^4.
21.3x>9
24.4*3"',.
Note;
( 1 ) tor
(2) SVJ
(3) £ur
(20x30) 9.2 (12)
2 (30x40; 18.3 (?4)
f <40n55) 33 6 (4411
. < 50x70) 52.0 {i-S}
i (60*80) 78.7 (103)
0 {70,95*, 108.6 (142)
i (80x110) HV.1 r°K;
•"r*te volumes • ,:''V"f 81 10X -J-
sl includes 5X jc^" cverleo '*• -
^ area ste.-:- at 6" f 6" sp£.c>,vj
Corns irwnt Wash Length Wei]
r* (ir.'* Ceniabter* (in) Oia. OB (in) m (Ft.) kg (Ib.)
V. - , a.Q) 11.4 '4. 5) U.95 (3/8) 610 (2,000) 340 (750)
-.' ' • 'I'. 12.7 (5. (•) 0-95 (3/8> 1/bS (5,800) 6^9 (1,430)
'' i .')'- ''.^ {S 0'. 0.95 (3/8) 2 000 (6 560) 1 120 (2 465)
",:., .. •'. •: : o f-: \ .27 {I--; ?,772 (9,129) 2,770 (6,110)
:*.-.' • . . .' -.-•! 1.27 ;1/2' 3,955 v"i2,V75) 3,945 (3,695)
T- ' • •. S ' .2^ {•-?> 5,iOO -<:i ; uv"-;-^ ;a , -tt-c-1 jo'nts - 20 diemeters or 12'- minimum.
T :. '. , - . 'r.wf! - -.>'*.' btibC" witf! an 18" extension into the concrete pad.
Steel Pattern
Pad t Walls
at (in)
30.5x30.5
30.5x30.5
30.5x30.5
30.5x30.5
30.5x30.5
30.5x30.5
30.5x30.5
(12x12)
(12x12)
(12x12)
(52x123
(12x12)
(12x12)
(12x12;
Spacing (3)
ca (in)
15.2>'5.2 (6x6)
15.2x1: .,: (6x6)
15 2x1-- ' (6x6)
15.2xij.l' (6x6)
15.2x1'.. ; (6x6)
15 -2x i'. ,2 (6x6
15. It, . ,2 (6x6
-------
PESTICIDED STORAGE AREA
< SECONDARY CONTAINMENT >
WAItK
SUPPLY
i?INSATE STORAGE
MINIBLJLK & SV« STORAGE
- RRE EXTINGUISHER
EMERGENCY SHOWER
8, EYE WASH
IVi
00
MIXING / HANDLING
AREA
SHALLOW
STAINLESS
STEEL SUMP
WITH GRATE
LOADING/WASH PA3
( SECOM3ARY CONTAINMENT )
1,3- 1.5 W
(With Building)
Figure i.
-------
G*
! Ssi
yj f , if », jj|
4 -T __ "L _ ___
j ^ U. _^. .,.,._,-, ^ __
\
,
-
I C
CM
0)
3
cn
H
129
-------
oei
-------
WATER
SUPPLY
MIXING AND
CONTAINMENT
FERTILIZER
STORAGE
FLOOD
FIRE \ LIGHT
EXTINGUISHER
PESTICIDE
STORAGE AREA
WORKER SAFCTY AREA
CMERGENCV SHOWER t EYEWASH
SECURITY
FENCE
R1NSATE AND SVR
STQRGAE
MIXING / HANDLING
AREA
Figure 4.
-------
©
c
1
1
/
%
.
E
\
[
V
(B)
©
J
1 ' ' 1
"
i
L
f ~!
OVERLAP REi
/20d. 50cm(12
::::::± Q%\
y^::::::± J
R" DIA STEEL BOTH
-"-DIRECTIONS @3Qcm(12'}CC-
VAP1ABLE v ,
— ^ A I
f^ 1
TYPE D CONTROL JOINT. 0.35-0.
(V'V) xW-PHEMOLDED -\
,STRIP FLU SH WITH S;URFACE\_
VARIABLE !
SLOPE v.^ i
VAFtASLE SECURITY FEN
SLOPED / | rS~
2% f
»- ("-A) L^
RINSATE STORAGE f
L_!L_ L_!L_|L_ '
^ r^.
r~ ~~r
BAR !
) MINIMUM
i
!
j
i
i
L ;
K^PE^
r r\
**. 0*
5 ! WASH PAD
70cm. i j
.._J..J
I Q jj : VARIABLE
L "X" SLOPE
' ^\
Stainless
/Steel sump
CE / 1 VAFVBLE
"Sjf ' SjjDPE
") IMK/J || * 2/'
±rj |LOAd u (ii.^
I l(ll-C) | 'U— CHEMICAL
|k II STORAGE
/ «, g SECURITY
L-rV_/__J
— ™ • • D
• -s
_
-
1
i
~*©
A
1
Figure 5.
132
-------
LB/EL
CA>
SECTION E-E t SIDE VIEW CROSS SECTION OF WASH PAD a CONTAINMENT SECTION
r
1J-
^
SECTION D-D EDGE CROSS SECTION SIDE VIEW OF WASH PAD 4 CONTAINMENT SECTION
UB/H.
=T3t:
Figure 6.
-------
I
I
1
l*t
n
0.
1
^n
i
^
t-
-------
© r"®
C
i
'
A
\
e
i
•L
K
M
©
»
1'
j
y
A
R" DIA S
1— --DIRECTI
T
TYPE D CO
V-V xV4P
(STRIP FLU
OVERLAP RE
/20jd. 12'MINIk
• ! °i
TEELBOTH
ONS~@12'CC — •"
V/fi|ABLE\ L
SLOfE \ (^
NTROL jq'lNT\
•REMOLDED -\
3H WITH SURFACED
I
SLOPE xj
SECURITY !
FENCE-? !
ViSflfcBLE / ; r -
*=- / J iC
^ ^
BAR j
r
iUM j
j
FERTILISER APPLICATOR
WA^ Hi LOADING
i
L i
_ /vnrsi
-
s " "
I.J _
p /-»
] f^~\\ FEHTIUZB* Vinfr
GT(D
•^ ;c
BULK TRAILER UNLOAD PAD C
4- r
1 L ^
J
^^
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i
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-------
Waste Minimization for
Non-Agricultural Pesticide Applicators:
EPA's Pollution Prevention Guide
by
Teresa M. Marten
U.S. Environmental Protection Agency
Office of Research and Development
Risk Reduction Engineering Laboratory
Cincinnati, Ohio
INTRODUCTION
U.S. EPA's Office of Research and Development is preparing a guide to be
published later this year for non-agricultural pesticide applicators which will
provide specific information about waste minimization for pesticide users in
industries such as commercial lawn care, structural pest control, greenhouse
operations, and forestry. The guide is being published under the authority and
responsibility given to EPA under the 1984 Hazardous and Solid Waste Amendments
to the Resource Conservation and Recovery Act (RCRA). As the federal agency
responsible for writing regulations under RCRA, the U.S. Environmental Protection
Agency (EPA) has an interest in insuring that new methods and approaches are
developed for minimizing hazardous and other wastes and that such information is
made available to the industries that generate waste. The guide being developed
for non-agricultural pesticide applicators is one in a series of industry-
specific pollution prevention guides that will assist companies from selected
industries in minimizing wastes generated within their operations.
EPA has defined waste minimization to consist of source reduction and
recycling. In EPA's four tiered waste management hierarchy, which presents the
Agency's ordered strategy for addressing waste generation and management, source
reduction and recycling are the top two tiers:
• source reduction
• recycling
• treatment
• disposal
Of the two waste minimization approaches, source reduction -not creating waste
in the first place - is considered environmentally preferable to recycling. The
recently passed "Pollution Prevention Act" of 1990 further emphasizes the
preference for source reduction in that Congress requires EPA to carry out a
number of activities related to researching and promoting source reduction. The
treatment and disposal of wastes, long the focus of EPA's research and regulatory
attentions, are considered neither waste minimization nor pollution prevention.
EPA'S WASTE MINIMIZATION OPPORTUNITY ASSESSMENT MANUAL
Before EPA began work on developing industry specific guidance manuals for
waste minimization, EPA's Office of Research and Development (ORD) published a
general manual for waste minimization which can be used by companies within all
industrial and commercial sectors, including non-agricultural pesticide users.
136
-------
The Waste Minimization Opportunity Assessment Manual (USEPA 1988) describes how
to conduct a waste minimization assessment and develop options for reducing waste
generation. It explains the management strategies needed to incorporate waste
minimization into company policies and structure, and discusses how to establish
a company-wide waste minimization program, conduct assessments, implement
options, and make the program an on-going one.
The systematic procedure outlined in the manual for carrying out a waste
minimization opportunity assessment (WMOA) has four phases. They are: 1)
planning and organization, 2) assessment, 3) feasibility analysis, and
4) implementation. In the planning and organization phase, essential elements
are: getting management commitment, setting waste minimization goals, and
organizing an assessment task force. The next phase, the assessment itself,
involves the following steps:
1. Collect waste generation data
2. Prioritize and select assessment targets
3. Select assessment team
4. Review data and inspect site
5. Generate options for reducing waste
6. Screen and select options for feasibility study.
Options that pass the assessment screening are carried into the third
phase, the feasibility analysis, in which a technical evaluation and an economic
evaluation are performed. The technical evaluation determines whether a proposed
option will work in the specific application that is envisioned at the company.
During the feasibility phase, an economic evaluation is carried out to analyze
the cost ramifications of implementing an option using standard measures of
profitability, such as payback period, return on investment, and net present
value.
Finally, in the fourth phase, implementation, the options that pass
technical and economic feasibility reviews should be executed. It is then up to
the assessment team, with management support, to continue the process of tracking
wastes and identifying opportunities for waste minimization by performing
periodic reassessments.
INDUSTRY SPECIFIC POLLUTION PREVENTION GUIDES
While the WMOA manual has been very popular and has proven successful in
providing generic guidance to industry for establishing waste reduction programs,
EPA's Office of Research and Development wanted to build on this achievement by
offering recommendations for waste reduction techniques and technologies that
were industry specific. And so in 1989, ORD's Pollution Prevention Research
Branch began developing a series of industry specific pollution prevention
guidance manuals.
The manuals are based on existing waste reduction reports already developed
for targeted industries by the State of California Department of Health Services
(DHS). California's DHS performed waste reduction assessments for several
businesses within an industrial category and compiled them in a report for the
industry. What EPA is doing is modifying and augmenting the California reports
so that they are comprehensive, nationally applicable guidance documents. The
EPA manuals describe wastes and waste generating processes within the subject
137
-------
industry followed by specific suggestions for reducing these wastes through
source reduction and recycling. Also provided are industry-specific worksheets
to assist companies and environmental professionals in methodically conducting
waste minimization assessments for facilities within the subject industry.
In 1990, EPA published seven industry-specific pollution prevention guides,
and plans another 12 for 1991. One of the manuals already published, Guides to
Pollution Prevention: The Pesticide Formulating Industry. EPA/625/7-90/004, and
the manual to be published later this year for non-agricultural pesticide
applicators should be of special interest to this audience. It is this second
manual that is the subject of the present paper. Below, a summary will be
provided of the major recommendations for reducing waste generation within
companies and operations that use pesticides for non-agricultural purposes.
NON-AGRICULTURAL PESTICIDE APPLICATOR INDUSTRY PROFILE
The non-agricultural pesticide application industry consists of the
following types of firms: landscape maintenance firms, commercial nurseries, and
structural pest control firms, as well as government agencies that run these
kinds of operations. The SIC codes which apply to the industry are lawn and
garden services (SIC 0782), tree spraying (SIC 0783), ornamental floriculture and
nursery products (SIC 0181), food crops grown under cover (SIC 0182), forest pest
control (SIC 0851), mosquito eradication (SIC 4959), and disinfecting and pest
control services for dwellings and buildings (SIC 7342).
This group represents a sizable portion of the demand for and use of
pesticides. A 1980 study, which presented the results of a survey of pesticide
users classified into three categories: agriculture, industry and government, and
home and garden, attributed 21% of pesticides use to the industry and government
sector, roughly equivalent to the non-agricultural pesticide applicators group.
Of the remainder of pesticide used, agriculture accounts for 72% and only 7% is
due to home and garden use (Aspelin and Ballard, 1980).
WASTE GENERATION
Operational activities within the industry that have the potential for
generating wastes include: pesticide storage and distribution; pesticide mixing
and formulation; application of pesticides; cleaning of storage, mixing, and
application equipment; and waste management. Major waste streams within this
industry are: used protective clothing; empty pesticide containers; rinsate from
pesticide containers and applicators; and surplus inventory. In a broader, but
still very legitimate sense, pesticide wastes also include those pesticides
unnecessarily or over-applied to targeted areas and pesticides mistakenly or
inadvertently applied to non-targeted areas.
SOURCE REDUCTION
Source reduction as mentioned above is the preferred method of waste
minimization. It can be defined as any activity that reduces or eliminates the
generation of waste at the source, usually by substituting non- or less toxic or
hazardous chemicals for more highly toxic or hazardous chemicals, changing
operations and maintenance procedures to reduce waste, and technology innovations
138
-------
that improve efficiency of raw material usage.
Integrated Pest Management
Clearly, one of the best ways of minimizing pesticide waste is to minimize
pesticide use. By utilizing a whole range of approaches, including cultural,
biological and chemical methods, for controlling pests to acceptable levels,
integrated pest management (IPM) significantly reduces pesticide use. The amount
of reported reduction in pesticide use upon implementation of an IPM program
commonly ranges from 50% to 90% and above. Instead of relying on pesticide
application frequencies that are predetermined and calendar based, IPM strategies
only resort to chemical pesticide applications when other methods have failed and
plant or habitat monitoring indicates that chemical pesticide applications are
needed to prevent pest damage from exceeding economic or aesthetic thresholds.
An added advantage of IPM is that with decreased exposure to chemical pesticides
because alternatives are employed, pests are less likely to become resistant.
When chemical pesticides must be used they are likely to be more effective.
Much has been written about various IPM programs within the non-
agricultural sector, including descriptions of programs used for controlling
pests in forests and parks (Daar, 1987; Widin, 1987; and Nielsen, David, 1989;
Ticehurst et al., 1988; Collman, 1990) greenhouses (Helyer and Payne, 1986),
commercial lawn care (Leslie et al., 1989), and mosquito abatement. The
citations provided are only a partial listing; the literature describing IPM is
extensive for non-agricultural, as well as agricultural sectors. Because of the
success of IPM and the large reductions in pesticide use and pesticide waste that
can be achieved, an investigation of IPM alternatives should be a fundamental
part of any waste minimization program for the pesticides application industry.
Inventory Control
Within the pesticide applicator industry, as with any industry that uses
raw materials which in themselves are hazardous or toxic, proper inventory
management can prevent chemicals from becoming waste when shelf life has been
exceeded or improper storage has resulted in spills or spoilage. To avoid this
kind of waste generation, tight controls should be placed on ordering pesticides,
and only those needed for the current season should be purchased and stored on-
site. This reduces the chance that pesticide will become out-of-date or useless
due to bans on its use. Larger operations may want to go to a computerized
inventory control system. In the event that pesticide expiration dates are
exceeded, the prudent purchase of pesticides from suppliers who have policies for
accepting the timely return of full, unopened containers will avoid this material
from becoming waste.
Good storage and spill control provisions help reduce pesticides waste
resulting from spoilage and spills. Precautions should be in place to secure
pesticide storage locations and to prevent entry and mishandling by unauthorized
personnel. Only a limited number of trained personnel should have access to
storage areas. To reduce the possibility of spoilage, pesticides should be
stored in areas that are protected from moisture, sunlight, and extremes in
temperature. Most pesticides have a longer shelf life if stored in cool, dry
areas out of direct sunlight (Ware, 1983). To reduce the possibility of spills,
exposure to high activity areas, floor traffic and machinery should be avoided.
Pesticides should be stored on pallets or shelves that allow for easy, periodic
inspection for signs of damage or leakage. To isolate and properly handle those
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spills that may occur, storage areas should have secondary containment or
drainage control (California DHS, 1991).
Product Substitution
Pesticide wastes may be reduced by replacing or substituting a toxic
pesticide with one that is less toxic. Examples include using biodegradable or
short-lived herbicides instead of those that are very persistent; using
relatively non-toxic insecticidal soaps instead of toxic insecticides; using
pesticide formulations that rely on less toxic "inerts" for active ingredient
carriers, such as water instead of solvent; and using non-chemical or mechanical
pest control devices such as traps instead of chemical pesticides (California
DHS, 1991).
Choice of formulation can minimize loss of pesticide to the non-targeted
environment as well as reduce worker exposure. Solid formulations for popular
sprayable products, which must be dispersed in water before spraying, may be sold
as wettable powders, dry flowables, or water dispersible granules. While the
powders have significant dust making potential, especially when conditions are
windy, dry flowables and water dispersible granules have the advantage of being
dust free if they are well designed. Liquid formulations that carry especially
toxic actives, can be microencapsulated to improve their safety and reduce
release to the non-targeted environment (Hudson and Tarwater, 1988).
Containers and Packaging
Containers that are triple rinsed are not regulated as hazardous waste, but
they remain a source of solid waste if disposed of and not recycled. (The
recycling of rinsate and containers will be covered below). Businesses should
take a critical look at their container wastes. Product should be purchased in
the size container needed for one season's usage and, to minimize waste
containers, the procurement of multiple small containers should be avoided. The
use of refill able containers could be explored by purchasers and suppliers. For
example, pesticide applicators could purchase and dispense product from
refillable containers. Fifteen- gallon small volume returnable containers are
available for some termiticide products.
The purchase and use of pesticide in premeasured water soluble packages can
eliminate packaging as a source of waste because the packaging dissolves and
becomes part of the application mixture. Cleanup of measuring and mixing
equipment is also avoided. Certain pesticides that are marketed as wettable
powders can now be purchased in water-soluble, polyvinyl alcohol film packets
that are added directly to application equipment. Water-soluble packaging is
also being investigated for liquid pesticides sold as emulsifiable liquid
concentrates. (Hudson and Tarwater, 1988)
Improved Mixing and Application Technology
Wastes from mixing and application processes can be minimized by a
combination of good standard operating procedures and improved mixing and
application technology. By mixing only enough pesticide for the job at hand,
using premeasured water soluble packages if available, and using closed mixing
systems, wastes can be kept to a minimum. (Marer et al., 1988). In addition,
computerized mixing and application systems are now available that reduce
cleaning requirements and have the added advantage of accurately controlling the
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quantity of pesticide applied. In these systems pesticide and water are
independently pumped to spray nozzles by computer controlled metering pumps and
mixed directly in the nozzle, thus eliminating the need for a large volume
container for holding ready-to-apply diluted pesticide. (California DHS, 1991)
The correct application equipment for the job should be selected because
most application equipment used by the non-agricultural applicators group is
suited only to a limited number of situations (Marer et al., 1988). Equipment
too large for the job is likely to release pesticide to the non-targeted
environment as well as increase the amount of rinsate generated during equipment
cleanup.
With the advent of controlled droplet technology, the size of droplets
emitted from pesticide spraying equipment can be tightly controlled and
standardized so that exactly the right droplet size is generated by the spray
equipment, maximizing the amount of pesticide hitting its target. Historically
used high volume spray equipment reliant on hydraulic nozzles produces a wide
range of droplet sizes, from 100 to 1000 microns in diameter, some of which is
wasted: too large droplets may fail to meet their target, fall to the ground and
end up as run off, and droplets that are too small are prone to wind or drift
loss. Other waste minimizing technological improvements to the controlled
droplet sprayer are the ultra low volume sprayer and electrodyne spray
technology. (Sastry, 1987).
Application Sequencing and Application Timing
Cleaning requirements for application equipment can be minimized by proper
sequencing of pesticide applications. By applying all pre-emergent products in
sequence followed by all post-emergents, applicator cleanings between different
product types can be avoided. As an alternative, dedicated application equipment
for each type of pesticide would result in similar reductions (California DHS,
1991). By properly timing the application of pesticides, additional applications
can be avoided. For example, by applying pre-emergents at the correct time,
future applications of post-emergents may not be needed.
Weather conditions should be taken into account when planning pesticide
applications so that pesticide effectively meeting targeted plants or insects is
maximized. Application efficiency will be compromised on windy days and
applications should be rescheduled if windy conditions prevail. Depending on the
type pesticide applied, rain in small to moderate amounts can be a help or a
hindrance to pesticide application efficiency.
RECYCLING AND REUSE
According to EPA's waste management hierarchy, if wastes cannot be
eliminated via source reduction practices, recycling and reuse are the next best
solution to managing them. For non-agricultural pesticide applicators,
opportunities exist for recycling rinsate and product containers. Rinsewaters
generated by cleaning product containers, application equipment, and vehicles can
be recycled by using them as make-up water in new formulations that are
compatible with the specific rinsate. Plastic containers of the size used by
this industry are not widely recycled; however, several states have test programs
to investigate the feasibility of recycling the plastic containers used for
packaging agricultural pesticides.
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SUMMARY
The above provides a brief summary of the options for minimizing waste that
will be included in EPA's upcoming guide for non-agricultural pesticide
applicators. In addition to the presentation of options, the manual will include
a more detailed description of the industry than is presented here and will
include worksheets to assist companies in examining wastes generated as well as
opportunities for reducing them. Comments are invited from non-agricultural
pesticide applicators and the companies and/or universities that are researching
and promoting waste reducing techniques and technologies of interest to this
industry.
REFERENCES
Aspelin, A. L., and G.L. Ballard. 1980. "Pesticide Industry Sales and Usage: 1980
Market Estimates." Economic Analysis Bureau, Environmental Protection Agency,
Washington, D.C.
12 pp.
Burn, A.J., Coaker, T.H., and Jepson, P.C., Eds., Integrated Pest Management
Academic Press, Harcourt Brace Janovich, 1987.
California Department of Health Services, "Waste Audit Study Non-Agricultural
Pesticide Application Industry" Prepared for California DHS by Tetra Tech, Inc.,
March 1991.
Collman, Sharon J., "Integrated Pest Management: A Seattle Street Case Study"
Forestry on the Frontier: Proceedings of American Foresters National Convention,
Spokane, Washington, September 24-27, 1989, p 416-420.
Darr, Sheila, "Urban Integrated Pest Management: Policy Options for State and
Local Government" Pesticides and Pest Management: Proceedings of the 16th ENR
Annual Conference, November 12 and 13, 1987, p 295-299.
Helyer, Neil L. and Payne, C.C., "Current progress and future developments in
integrated pest management on protected vegetable crops" Aspects of Applied
Biology,
Vol 12, 1986, p 171-187.
Hudson, J.L. and Tarwater, O.R., "Reduction of Pesticide Toxicity by Choices of
Formulation" American Chemical Society, ACS Symposium Series, 1988 pp 124-130.
Leslie, Ann R. and Metcalf, R. L., Eds., Integrated Pest Management for Turfgrass
and Ornamentals USEPA Office of Pesticide Programs, August 1989.
Marer, Patrick J. The Safe and Effective Use of Pesticides
University of California Statewide Integrated Pest Management Project Division
of Agriculture and Natural Resources Publication 3324 University of California,
Davis, 1988.
Nielsen, David G., "Integrated Pest Management in Arboriculture: From Theory to
Practice" Journal of Arboriculture, Vol.15, No.2, February, 1989, p 25-30.
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Sastry, V.C. "Pesticide Application Techniques in Integrated Pest Management"
Plant Protection Bulletin Vol 39: 1-2, 1987 p 23-26.
Ticehurst, Mark and Finley, S., "An Urban Forest Integrated Pest Management
Program for Gypsy Moth: An Example" Journal of Arboriculture, Vol. 14:7, 1988,
p 172-175.
U.S. Environmental Protection Agency, Waste Minimization Opportunity Assessment
Manual EPA/625/7-88/003, 1988.
Ware, George W. Pesticides Theory and Application University of Arizona; W.H.
Freeman and Company, San Francisco, 1983.
Widin, Katharine, "Integrated pest management: A preventative approach to
landscapes" American Nurseryman, Vol. 165:10, 1987.
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Pesticide Container Management in the United States
by
Nancy Fitz
U.S. EPA
Office of Pesticide Programs
ABSTRACT
The disposal of containers is a very visible problem in the agricultural
pesticide industry. EPA's role in pesticide container management increased
drastically with the 1988 amendments to the Federal Insecticide, Fungicide, and
Rodenticide Act (FIFRA). Section 19 of FIFRA requires EPA to address pesticide
containers in three ways: to promulgate container design regulations, to
promulgate residue removal regulations, and to conduct a study of pesticide
containers and report the results to Congress. In fulfilling these tasks, EPA
has gathered a great deal of information on pesticide containers including use,
refill, residue removal, and disposal. The two most common disposal methods for
nonrefillable containers are landfill ing and open burning, although there are
problems associated with both of these options. Recycling is becoming an
increasingly viable pesticide container management option. As a result of the
container study, EPA has developed a container management strategy, including a
hierarchy of desirable containers. The hierarchy is designed to reduce the
number of containers requiring disposal. To accomplish this, EPA would like to
encourage the use of refill able containers and water soluble packaging as well
as increasing the number of containers being recycled.
INTRODUCTION
The disposal of containers is a very visible problem in the agricultural
pesticide industry. Accordingly, pesticide containers have received a
significant amount of attention beginning with a National Conference on Pesticide
Containers in 1972. At the 1985 National Workshop on Pesticide Waste Disposal,
container disposal was a focus of the keynote address. Additionally, another
speaker at the 1985 workshop discussed the three feasible options for managing
empty containers:
• Return for reuse or refilling;
• Recycling to the scrap stream or use for energy recovery; and
• Disposal by burial or burning in approved facilities. (Trask, 1985).
These are still the three main options available for pesticide container
management, although all of the options have changed since 1985.
EPA's role in pesticide container management increased drastically with the
1988 amendments to the Federal Insecticide, Fungicide, and Rodenticide Act
(FIFRA). Section 19 of FIFRA requires EPA to address pesticide containers in
three ways:
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• To promulgate container design regulations;
• To promulgate residue removal regulations; and
• To conduct a study of pesticide containers and report the results to
Congress.
Specifically, the study is required to develop options to encourage or
require:
• The return, refill, and reuse of containers;
• The development and use of formulations that facilitate residue
removal; and
• The use of bulk storage facilities to reduce the number of containers
requiring disposal.
In the past two years, EPA has worked with many of the people involved with
pesticide containers, including industry trade organizations, State agencies,
equipment and container manufacturers, packaging experts, and many individuals
such as distributors, dealers, commercial applicators, and farmers to gather as
much data on pesticide containers as possible. This information is compiled in
the report to Congress and is being used to develop the regulations.
The container design and residue removal regulations are intended to apply
to containers in all segments of the pesticide industry including agricultural,
institutional, industrial, household, and specialty markets. EPA has data that
show there are approximately three times as many aerosol pesticide containers
(used almost exclusively in the household and institutional markets) produced
each year than agricultural pesticide containers. Despite the wide range of
pesticides intended to be included in the regulations, this paper will focus on
the agricultural segment of the pesticide industry.
A great deal of progress has been made in the past five years in terms of
pesticide container disposal and waste minimization, although there are still
problems. This paper will briefly present the common types of containers in the
agricultural pesticide industry, discuss the disposal options for nonrefillable
containers, and describe the EPA container management strategy.
CONTAINER TYPES
EPA has divided pesticide containers into two major types: nonrefillable
and refillable. Nonrefillable containers are considered one-way or "throw-away"
packages. Generally, nonrefillable containers are relatively small, although
there is no maximum size limit. Nonrefillable containers include 1- and 2.5-
gallon jugs, 5-gallon cans and pails, bags, bag-in-a-box designs, aerosol cans,
and water soluble bags. One major change in nonrefillable containers in the
1980's was the nearly universal adoption of plastic as the major packaging type.
Plastic containers were introduced to the pesticide market in the late 1970's
and, with the exception of aerosol products, have become the dominant container
type for liquids. Most recently, with the advent of dry pesticide products that
require smaller amounts of active ingredient per unit area, more of these
products are being packaged in plastic jugs.
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Refillable containers are designed and intended to be refilled with
pesticide for further sale or distribution. The construction materials and
design specifications are generally selected to maintain the structural integrity
of the container under adverse storage, shipping, and use conditions over the
course of multiple fill and use cycles. Some of the containers that fall into
this category are bulk storage tanks, minibulks, small volume returnable
containers, and refill able bags.
MANAGEMENT OF NONREFILIABLE CONTAINERS
As discussed in the introduction, the relative use of the container
management and disposal options available in 1985 have changed. This section
addresses the methods currently used to dispose of nonrefill able containers and
recycling; reuse and refilling are discussed in greater detail in the next
section.
Many states have done surveys to determine the container disposal methods
used by farmers and dealers. Table 1 contains the results of a survey done by
the Minnesota Department of Agriculture in 1988, which is representative of the
various surveys.
Table 1
Methods of Container Disposal (Minnesota, 1988)
Percent of Respondents Who Use Method1 (%)
Disposal Method Farmers Dealers
Burn
Rinse/take to landfill
Rinse/bury
Return to dealer
Store on site
Salvage
Can't dispose
Out-of-state hazardous
waste landfill
Other
65.0
23.7
27.5
17.8
11.8
3.6
2.8
1.3
14.2
30.1
56.1
8.3
7.8
7.4
11.5
3.2
0.7
7.6
1 The columns total to greater than 100 percent because respondents could list
more than one disposal option.
By far, the two most common disposal methods for nonrefill able containers
are landfilling and open burning. Also, in some states, a significant number of
farmers bury containers on their own property.
However, there are problems with these disposal methods. An increasing
number of farmers, commercial applicators, and dealers are having their
containers rejected by landfill operators for several reasons:
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• Existing landfill space is diminishing and siting new landfills is
difficult;
• Concern for ground water contamination from earlier disposal practices
is increasing;
• States are adopting solid waste management strategies that rank
landfill ing as the least desirable disposal option; and
• Potential liability for future releases of hazardous substances exists.
Open burning is restricted or prohibited by a number of Federal and State
regulations. The open burning of pesticide containers is a good example of the
interjuristictional nature of pesticide disposal issues and involves regulations
on air, solid waste, and pesticides. Additionally, burying containers presents
a certain risk of contaminating soil, ground water, and surface water.
Because of the difficulty and problems associated with the disposal of
nonrefillable containers, a number of container collection and recycling programs
have begun. EPA is aware of such programs in Mississippi, Oregon, Iowa, Florida,
Illinois, North Carolina, Missouri, and Washington. Currently, most of these
programs are in the pilot project stage, although many are expanding. Also,
Maine has a deposit and return program, although it does not involve recycling.
The existing collection and recycling programs are all different. For
example, some are run by the State and others by industry. Additionally, some
of the programs collect only plastic containers, while some accept both plastic
and metal. However, there are two common features of the collection and
recycling programs:
• Properly rinsed containers are essential for a successful program; and
• Inspection of the containers is necessary to ensure proper rinsing.
EPA believes that these are two crucial aspects of establishing successful
container collection and recycling programs.
EPA CONTAINER MANAGEMENT STRATEGY
Several general conclusions relating to the development of a pesticide
container management strategy emerged from EPA's study and report to Congress.
Part of this strategy includes promulgating the container design and residue
removal regulations. Additionally, the pesticide container management strategy
includes long-term goals, which can be divided into several main categories.
Formulation and Container as a Unit
The first long-term goal is to have the pesticide industry consider the
pesticide formulation and its container as a single entity. This would require
a significant change in philosophy. Generally, formulating and packaging a
pesticide are separate projects done by different groups within a company or by
different companies altogether. The change in perception from considering a
container simply as a vessel to transport a pesticide to seeing the container as
an important part of the pesticide itself is an integral step in the long-term
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improvement of containers. The relationship between the container and the
pesticide is important in all stages of the pesticide/container life cycle,
including use of the container (transportation, storage, transferring pesticide
from the container, etc.), residue removal, and disposal of the container.
Provide Leadership
The second long-term container management goal is to provide leadership in
the area of pesticide containers. The container study involved a great deal of
cooperation between EPA, other Federal agencies, State agencies, industry groups,
environmental organizations, and many individuals involved with pesticide
containers. EPA would like to continue this dialogue and cooperation in the
future.
Move Toward Environmentally Preferable Containers
Another part of EPA's leadership role is to monitor and affect the trends
of pesticide containers. In conducting the study, EPA determined that there are
several desirable classes of containers. EPA has identified a hierarchy of
environmentally sound container classes. This hierarchy is based on information
collected on the use of containers, residue removal, and disposal, as well as
pollution prevention and reducing solid waste. The Agency would like to
encourage the development and use of the most desirable container classes. These
container classes are described in the following hierarchy.
This hierarchy is based on the characteristics that EPA has identified for
optimal pesticide containers. Any efforts, both public and private, to address
pesticide containers should strive for:
• Protection of the integrity of the pesticide product and the
environment through which the container passes;
• The safe and easy transfer of pesticide from the container to the
application equipment;
• Minimization of the amount of unused pesticide residue remaining in the
container after the pesticide has been transferred; and
• Minimization of the number of pesticide containers requiring disposal.
Preferred Pesticide Container Hierarchy
The hierarchy of preferred pesticide container classes is given in Table
2. The most desirable container classes are on top and the least desirable are
on the bottom. For the purposes of this paper, a container is considered
recyclable if the technology exists to recycle the material from which the
container is constructed.
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Table 2
EPA Pesticide Container Hierarchy
Refillable containers and water soluble packaging
Nonrefillable, recyclable containers that are currently being recycled
Nonrefillable, recyclable containers that are not currently being recycled
Nonrefillable, nonrecyclable containers
The first two characteristics of optimal containers -- protection of the
pesticide product and the environment, and the safe and easy transfer of
pesticide -- are functions of the container design. Therefore, these two
characteristics are generally independent of the position within the hierarchy,
although they vary within each class. Improperly designed or handled containers
in the most desirable category may be potentially more harmful than the best
designed or handled containers in the least desirable category.
Refillable containers and water soluble packaging are the most desirable
container class because they:
• Reduce or eliminate the need for residue removal; and
• Reduce the number of containers requiring disposal.
The next category -- nonrefillable, recyclable containers currently being
recycled -- is attractive because it reduces the number of containers requiring
disposal as waste.
The third category, nonrefillable, recyclable containers not currently
being recycled, includes most nonrefillable steel and plastic containers. Also,
the steel industry maintains that aerosol cans are recyclable, although EPA
believes additional study is necessary in this area. With the proper
infrastructure and market, the containers in this category could move up the
hierarchy to reduce the number of containers requiring disposal.
The least desirable category, as determined through the study, are
nonrefillable, nonrecyclable containers. Because multiwall paper shipping sacks
are usually constructed of more than one material (e.g., kraft paper and a
barrier layer), they are not recyclable.
In summary, EPA is addressing pesticide containers in several ways. EPA
would like to reduce the number of containers requiring disposal by encouraging
the use of refillable containers and water soluble packaging. Also, EPA would
like to increase the number of pesticide containers that are being recycled. At
the same time, EPA is addressing pesticide container issues on a broader scale
than just disposal. The container design and residue removal regulations that
are being drafted are intended to increase safety during use, refill, residue
removal, and disposal of containers.
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ENDNOTES
Minnesota Department of Agriculture. Minnesota Empty Container Disposal Report,
March 1988.
Trask, Harry W. "Empty Pesticide Container Management: An Overview,"
Proceedings: National Workshop on Pesticide Waste Disposal, JACA Corporation,
Fort Washington, Pennsylvania, September 1985.
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PESTICIDE DISPOSAL IN GUINEA-BISSAU: A CASE HISTORY
by
Janice Jensen
US Environmental Protection Agency, Washington DC 20460
ABSTRACT
Guinea-Bissau is a small, underdeveloped country on the southwestern coast
of Africa. In June 1990, the Guinea-Bissau Crop Protection Service (CPS)
requested USEPA assistance with disposal of surplus pesticides. This paper
describes the problems encountered, and outlines several practical disposal
options which were presented to the CPS. These low-cost, low-technology
approaches can provide developing countries such as Guinea-Bissau with viable
methods of pesticide disposal.
INTRODUCTION
Although the chemical approach to pest problems can significantly improve
crop yields and reduce the incidence of insect-borne diseases, without careful
handling, pesticides also can pose a serious threat to human health and the
environment. One unfortunate consequence of chemically-intensive pest control
programs is their tendency to generate potentially toxic wastes. The problem of
disposal of obsolete or unwanted stocks of pesticides is of vital concern,
particularly in developing countries which may lack the technical expertise or
financial resources necessary to accomplish sophisticated disposal solutions.
Disposal of unwanted pesticides is of special concern in Africa, where
severe tropical climates cause chemicals and their containers to deteriorate more
rapidly and where poor storage practices are common. (Jensen, 1983; Jensen,
1987a; Jensen, 1987b; Jensen, 1990; Krueger, 1989) Aging pesticide drums are
frequently encountered being stored in the open sun, with leaking chemicals
posing a direct threat to human health and surface or groundwater quality.
In the countries in and near the Sahara desert, thousands of tons of
obsolete pesticides stocks require disposal. (GIFAP, 1991; World Environment
Center, 1987) Many of these stocks were purchased in the late 1960's to control
pests such as migratory locusts, tsetse flies and other insects, Quelea birds and
weeds.
Government officials in these countries are acutely aware of the potential
problems posed by these obsolete stocks, but are unaware of feasible, low-cost
options for implementing their safe disposal.
•To whom correspondence may be addressed. J.K. Jensen's current address is Pesticide Management &
Disposal Staff, Environmental Fate and Effects Division (H-7507C), Office of Pesticide Programs, US
Environmental Protection Agency, 401 "H" Street SU, Washington DC 20460, USA.
Presented at the International Workshop on Research in Pesticide Treatment, Disposal, and Waste
Minimization, Cincinnati, Ohio, USA, February 26-27, 1991.
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This paper provides a case study of surplus pesticide problems in the
developing African country of Guinea-Bissau and describes several practical, low
cost disposal options which the USEPA identified for the Guinea-Bissau
authorities.
BACKGROUND INFORMATION
Guinea-Bissau is a- small, underdeveloped country, located on the
southwestern coast of Africa. The capital city of this predominantly agrarian
nation is Bissau. Table 1 provides limited economic statistics for this country.
TABLE 1
Economic statistics for Guinea-Bissau
$160 per capita income
36,125 square miles
900,000 population
90% rural population
20% adult literacy
134/1000 infant mortality
90% employed in agriculture
Self-sufficiency in staple food production is a national priority in
Guinea-Bissau. To assist in achieving this goal, in 1978 the U.S. Agency for
International Development (USAID) initiated a $4.25 million dollar crop
protection. (USAID, 1988) The purpose of the project was to strengthen the
capacity of the National Crop Protection Service (CPS) so that it could develop,
direct and implement its own crop protection program. The USAID project ended
in September 1990.
The USAID program developed integrated pest management (IPM) as the crop
protection strategy of choice, with the use of pesticides as a key element of the
IPM program. CPS concerns regarding the importation, storage, handling, and
disposal of pesticides as well as the management of pesticide containers resulted
in formal requests to the USEPA for technical assistance before the end of the
project. This assistance was provided by the author in June 1990. Although
assistance was provided in all of these areas, only the disposal portion of the
assistance will be addressed in this paper.
DISPOSAL OF "OLD" PESTICIDE STOCKS
As an initial step, the CPS conducted an inventory of all pesticide stocks
in country, including pesticides potentially requiring disposal. (Castleton,
1990; CPS, 1990) Generally, these pesticides had been stored under
unsatisfactory conditions for many years, and the Service was uncertain of the
quality of the products and the integrity of their containers. No quality
testing laboratory was available in Guinea-Bissau to assist in this evaluation.
The pesticides ultimately identified for disposal, primarily on the basis of
their age and the condition of their containers, are listed in Table 2.
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TABLE 2
Pesticides for Disposal in Guinea-Bissau
Pesticide
carbaryl (Sevin*)
dichlorvos (OOVP*)
dicofol (Kelthane*)
edifenphos (Hinosan*)
fenitrothion (Agrothion*)
fenthion (Baytex*)
phoxim (Volaton*)
triadimefon (Bayleton*)
pesticide with no label
c = carbamate
op = organophosphate
oc = organochlorine
* = trade name
Chemical
Type
c
op
oc
op
op
op
op
Quantity
6,4001
3501
6001
6001
781
1001
1,0001
75kg
2001
Warehouse
Location
Bissau
Contuboel
Bissau
Sonoco
Bafata/Contuboel
Bafata
Contuboel
Bafata
Bafata
The next step was to develop practical, low cost options for the disposal
of these relatively small quantities of over-age pesticides. Carbaryl, the only
pesticide present in significant quantities, was considered separately.
CARBARYL DISPOSAL
The Carbaryl Story
Carbaryl (6,400 liters) was imported into Guinea-Bissau in 1988 for the
locust campaign being carried out by donor organizations in West Africa. The
carbaryl formulation purchased was Seven 4-Oil, chosen primarily because it could
be aerially applied and because it contained sticking agents which enhanced its
persistence on foliage.
Because the oil-based formulation was a thick suspension, an agitation pump
was needed for application. However, the outbreak of a more severe locust
infestation in neighboring Senegal caused a realignment of priorities, and the
spray plane and agitating pump destined for Guinea-Bissau never arrived.
Consequently, none of the carbaryl was used.
All of the carbaryl drums were stored in one warehouse near the capital
city and were in good condition. However, because the drums had never been
agitated or rolled as recommended on the label, the carbaryl settled in the
containers and resuspension efforts by the CPS proved futile. This eliminated
the possibility for using the carbaryl for other locust control methods such as
coating grains to make baits, or for application with available ground
equipment.
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Return To Sender
One disposal option identified for these carbaryl stocks was to return them
to the US manufacturer for reformulation and resale, with the manufacturer paying
for transportation costs. This course of action was being pursued for remaining
carbaryl stocks in neighboring Senegal and was strongly recommended to the CPS.
The CPS was advised to decide quickly, as shelf-life considerations for carbaryl
limited the time for which this option was viable. The manufacturer could
reformulate and resell the carbaryl, but not if its effective date had expired.
In-country Disposal
This was a less desirable option. There was no high temperature
incinerator or dedicated hazardous waste landfill in Guinea-Bissau. Co-firing
pesticides as fuel in a cement kiln is being considered in several African
countries and this method of disposal may be appropriate when there are large
amounts (>50 metric tons) of pesticides to be discarded. (World Environment
Center, 1987; Krueger, 1989) Although it can be a practical and efficient method
of disposal, cement kiln incineration of wastes typically invites a variety of
technical and political complications. (Jensen, 1987b)
Land burial of the carbaryl was not recommended. Because of a high water
table and routine flooding in most areas in Guinea-Bissau, there is a real
potential for groundwater contamination or for run-off into receiving waters,
streams, drinking water or other pathways that affect the environment.
OTHER PESTICIDES FOR DISPOSAL
For the pesticides in Table 2 other than carbaryl, practical, low cost
options were recommended for the disposal of these relatively small quantities
of over-age pesticides.
Find Safe Alternative Uses
In a country like Guinea-Bissau with extremely limited financial resources,
taking advantage of the economic benefit of the pesticide product is always the
preferred method of disposal. Finding safe alternative uses for pesticides of
questionable integrity was recommended.
A strategy for obtaining additional information on alternative uses and
methods for safe disposal for the pesticides in Table 2 was worked out with the
CPS. A first step in the strategy was to test the products for quality. Six of
the nine pesticides in Table 2 are products of Bayer Chemical Company. The USEPA
consultant recommended that the CPS request that Bayer -- at no charge to the
CPS, which has no foreign exchange to pay for the analysis -- analyze samples of
their products in Guinea-Bissau for quality. It was possible that this request
would be granted, considering the enhanced product stewardship programs now in
place with the large chemical companies. Bayer would advise the CPS how to
safely collect and ship the samples for analysis.
Many of the pesticides in Table 2 potentially can be used
to control pests where the exact dosage rate is not critical. (Farm Chemicals
Handbook, 1990; Asian Development Bank, 1986) For example, dichlorvos could be
sprayed on the inside of the walls and ceiling of mud grain storage bins to limit
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pest infestation. Phoxim is also registered for controlling stored product pests
in granaries and for armyworm control. The dicofol could be used successfully
against the cassava green spider mite, which was identified in 1990 as a major
pest problem in Guinea-Bissau.
To summarize, it is preferable to use these chemicals as they were designed
to be used, rather than dispose of them. All possible effort should be made to
avoid disposal.
In-countrv Disposal
Chemical degradation was considered as a possible disposal option, given
that: 1) relatively small quantities were involved, and 2) most of the
pesticides in Table 2 are carbamates or organophosphates, which decompose when
treated with alkaline (basic) chemicals, such as lye or lime. (Lawless, et. al.
1975) Lime is readily available in Guinea-Bissau. (Chemical degradation was not
considered as a realistic option for the large stocks of carbaryl on hand.) A
"cook book" chemical treatment procedure using lime was provided to the CPS.
If the chemical degradation option is selected, the procedure is best done
in the middle of the dry season (January), not during the rainy season, when
water contamination would be of greater concern.
No Action
This option was not recommended. Other than the carbaryl stocks, the
containers for the pesticides in Table 2 are not in good condition. Some are
leaking and the released material has contaminated the porous concrete floors of
the storage areas and may have passed through to the ground. The fumes could
pose a risk of worker exposure by inhalation, and increase the risk of fires.
Most of the storage facilities are located in populated areas.
CONCLUSION
The purpose of the technical assistance to the Crop Protection Service was
to provide guidance on practical, low cost options for the disposal of relatively
small quantities of over-age pesticides. The intent of the Service was to
carefully consider these options, and start the implementation phase in the near
future.
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REFERENCES
Asian Development Bank, 1986. Study of Pesticide Usage in Selected DMC's of the
Bank, prepared by Cecilia Gaston and Roy Pavey.
Castleton, C., 1990. Trip Report-APHIS/IS, Region IV, Africa, by Carl W.
Castleton, Area Director (Africa), in Guinea-Bissau from April 23-30, 1990.
CPS, 1990. Materias e productos recebidos-disbribuicaes, camapanha Fitossanitaria
de 1990, prepared by Pedro Landim, Head of Field Operations, National Crop
Protection Service, Guinea-Bissau.
Farm Chemicals Handbook, 1990. Meister Publishing Company, Willoughby, Ohio,
USA.
GIFAP, 1991. Disposal of Unwanted Pesticide Stocks, booklet prepared by GIFAP,
the International Group of National Associations of Manufacturers of Agrochemical
Products.
Jensen, J.K., 1983. Trip Report to Dar es Salaam and Zanzibar, July 6-11983,
prepared by J. Jensen for USAID, REDSO/ESA, Nairobi, Kenya.
Jensen, J.K., 1987a. Trip Report - Pesticide Disposal Sana'a, Yemen, June 26 -
July 4, 1987. Prepared for the Consortium for International Crop Protection,
4321 Hartwick Road, Suite 404, College Park, MD 20740, USA.
Jensen, J.K., 1987b. Trip Report - USAID/OFDA Pesticide Disposal Survey Team to
Sudan, Ethiopia, Kenya and Somalia, May 28 - June 25, 1987. Prepared for the
Consortium for International Crop Protection, 4321 Hartwick Road, Suite 404,
College Park, MD 20740, USA.
Jensen, J.K., 1990, Pesticide Storage and Disposal in Guinea-Bissau, West Africa.
Trip report prepared for the USAID Guinea-Bissau Food Crop Protection Project III
and the Government of Guinea-Bissau, by Janice K. Jensen, Environmental Chemist,
USEPA, Washington, DC, July 1990.
Krueger, R., 1989. An Examination of the Problems Created by the Long-Term
Storage of Pesticides and Empty Drums (in Morocco) and Some Suggestions for
Management of the Problems, by R. Krueger, Office of Pesticide Programs, USEPA.
Lawless, et. al. 1975. Guidelines for the Disposal of Small Quantities of Unused
Pesticides, by E.W. Lawless, et al, prepared for the Office of Research and
Development, USEPA.
USAID, 1988. Guinea-Bissau Food Crop Protection III (657-0012) Project
Evaluation, USAID/Guinea-Bissau, February.
World Environment Center, 1987. Evaluation of Disposal Options RE: Pesticide
Waste in East Africa -- the Sudan, Ethiopia, Kenya, and Somalia.
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DOWNSTREAM INJECTION EQUIPMENT FOR SPRAYERS
AND FERTILIZER SPREADERS
by
Arthur W. Mclaughlin, Consumer Sales Manager
Agway Inc., MTS
Cortland, NY
Stanley A. Weeks, Ph.D., Director,
Farm Systems Research & Applied Technology
Agway Inc.
Syracuse, NY
01 in L. Vanderslice, Equipment Testing & Engineering Manager
Agway Farm Research Center
Tully, NY
INTRODUCTION
Agway Inc., a regional agricultural cooperative, owned by 91,000 farmer-
members provides truck mounted custom application spraying and spreading services
on farms in twelve Northeastern states. Motor Transportation Services (MTS), is
a division on Agway Inc. It is responsible for manufacturing and/or assembling
the truck mounted equipment that service 287 Agway owned stores, 350 certified
representatives, 54 fertilizer plants and contract operators for Agway. A total
of 213 liquid applicators and 219 lime and fertilizer spreaders at 80 locations
cover from 2,000 to 15,000 acres each per year with 90% of the liquid units
applying some kind of agricultural chemicals.
BACKGROUND
Because of Agway's total involvement with agriculture and the application
of crop protectants, fertilizer, and lime to improve crop production, Agway has
made major efforts to improve facilities, spraying and spreading equipment.
In 1975, a major research effort was initiated resulting in a new design
for spraying equipment which produced constant application rates regardless of
ground speed. This design in turn was reflected in less driver error and more
exact control of the amount of material applied per acre. These improvements
became standard on all new Agway spray trucks and were made available to retrofit
older spray units.
In 1977-78, Agway introduced impregnation (usually of herbicides) of dry
fertilizers in their fertilizer blend plants. This allowed spreading by all
available spreading equipment but caused some problems with cleanup in order to
prevent contamination of blend plant and spreading equipment. Also, segregating
and storing impregnated leftover material from field miscalculations of acreages
was a problem. Washing units after use and waste water disposal was a strong
concern during this time period. Agway studies showed that from seventeen to
twenty gallons of water were required to internally and externally wash down a
650 gallon sprayer unit and its booms.
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In 1983, a dilute pesticide management facility was constructed at the
Agway Farm Research Center (AFRC) at Tully, New York. This consisted of an
underground, roof covered storage system with an adjacent, interconnected
building with concrete washdown pad and an ag chemical storage room. This
facility was based on the design of the Iowa State units that had been
functioning successfully for several years. The idea was to construct and
monitor a unit that would serve as a model for possible future facilities at
Agway sprayer and spreader locations. Monitoring began in 1984 and continues to
the present in cooperation with New York State Department of Environmental
Conservation (NYSDEC). The facility has been operating continuously since it was
installed.
During the early 1980's, Agway cutbacks in people and research funding
delayed research work on experimental and/or prototype units but work continued
on studying the problems and travel to witness demonstrations of some equipment
made by other manufacturers. It was recognized that rinse pads and storage
structures were not only expensive but that the time required for sprayer units
to come in from the field to be cleaned and reloaded before going back to the
field was not cost effective. Studies were initiated on the concept of chemical
injection systems using positive displacement pumps as well as pump-tube units
during this period but funding to build a unit was unavailable and we could find
no one in the industry to cooperate with Agway in putting such a unit together
for field testing.
In 1986, some research funding became available and hydraulic boom controls
were designed allowing variable boom height adjustment and folding and unfolding
the booms—all done by a touch of the controls by the driver in the cab. This
innovation provided ease of changing from short to tall crops, hastened entering
and exiting fields and cut down on driver fatigue.
Also in 1986, a spray truck tank rinse and wash-down system was developed
that allowed the inside of the spray tank to be rinsed with clean water and then
sprayed off in the field. A hose and hand gun nozzle were a part of this system
so that after inside tank rinsing, the outside of the truck unit could be rinsed
with clean water before leaving the field and traveling down the road. An eye
wash system was also made a part of this cleanup system.
During this time period, a second look was taken of the direct injection
project and information was assembled from various resources. From this
assembled information, specifications for a system were established. The number
of modules, rate controllers and interfacing were specified to adapt to Agway
sprayer systems in the field. Agway selected a three module system with fifteen
gallon tanks, positive displacement pumps and range capabilities of 5 to 200
ounces per minute for each module. The Agway concept was to inject liquid ag
chemicals directly into the boom on a spray truck so that it could go to the
field with clean water in the tank and have as many as three separate crop
protectants and/or liquid fertilizers directly injected into the boom where they
would mix before being sprayed through the spray nozzles. Since each crop
protectant is carried in its own special container, at the end of the field the
container valves can be shut off, fresh water from the spray tank flushed through
the boom, and a clean machine is ready to leave the field and go to the next
customer with a clean rig and a clean tank of water (no rinsate or leftover spray
mixes for disposal). Such a system added from $8,000 to $10,000 to each sprayer
unit and no store location could be found willing to pay this additional cost for
a unit.
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In September 1989, Agway top management made the decision that at least one
of these injection units would be placed at strategic locations within the Agway
territory so that experience with operators, managers and customers could be
obtained. The plan was to place each unit at a site having an experienced,
well-trained driver and a diversified spray business that was well established.
With this mandate, nine downstream injection sprayer units were built and
eight of them were placed at strategic locations in the field during the Spring
and Summer of 1990. The ninth unit was kept at MTS for testing and research work
with chemical companies with new products. During the Spring of 1990, newly
formulated liquid and dry flowable ag chemicals from Monsanto and DuPont were
tested through the MTS unit.
In the early 1980's, pneumatic spreaders were new, were investigated, and
found to be inferior in spread pattern performance when compared with Agway's dry
spreader trucks. As time passed and more manufacturers entered the field, the
air spreaders showed improved performance. After six years of evaluation,
attending demonstrations, and testing different brands and models it was found
that the Tyler pneumatic spreader was the unit that could be recommended for use
by Agway.
In the Spring of 1989, a Tyler unit was purchased and put into service at
one of Agway's western New York locations. It had the capability for on-board
impregnation (both liquid and dry), which is a method of one-pass, in-field
mixing and application of herbicides and fertilizer. The key to this concept is
that it takes mixing away from the blend plant and puts it in the field where the
product is being applied. Only the amount of herbicide and/or fertilizer
required is applied and there is no mixed product to go back to the plant. It
also saves time and allows the fertilizer rate to be varied on-the-go.
DISCUSSION AND RESULTS
The Tyler air spreader successfully operated in the field for 6,200 acres
in 1989 and 8,200 acres in 1990. A new improved liquid injection system was
installed and replaced the old liquid system on the unit after the 1989 season.
Although this spreader unit has the capability of both dry and liquid fertilizer
impregnation, the operation manager and driver feel that the liquid system is
superior and used it exclusively during the 1990 season.
Each injection sprayer unit operated in the field covered from 2,500 to
14,000 acres for the 1990 season. A questionnaire was sent to each location and
filled out by the store manager and equipment operator. Follow-up personal
interviews were also conducted with some store managers and operators. From the
questionnaires and interviews Agway learned that some equipment modifications
will be forthcoming on all 1991 models that will retrofit the 1990 models.
Results of the first year of testing and interviews with fanners and Agway Crop
Center managers clearly indicate that application accuracy and protection of the
environment were both achieved with this type of equipment. Injection equipment
had the following advantages over conventional spraying equipment:
• Main spray tank contamination eliminated -- no unused product in the
main supply tank.
• Ground orientation was the most accurate system ever used.
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• Rate and chemical changes can now be made in the field.
• Costly run-outs and mix times are reduced or eliminated.
• Exact usage of chemicals.
• Unused chemicals can be easily transferred from 15 gal. module tanks to
containers.
• Reduced cost for wash down and containment areas.
• Environmental threats minimized.
• Ability to go to isolated, distant field locations and spray all day.
Acceptance of the injection sprayers by customers has been outstanding.
Most demand that their fields be sprayed with the new injection sprayers.
However, when asked, most are not willing to pay any more for the service than
for conventional, less accurate equipment. The dilemma faced by Agway is that
in high competition areas, spraying or spreading rates are determined by the
lowest bidder and expensive equipment will not pay for itself unless a higher,
more realistic fee is charged. Also, Agway is forced to charge the same price
per acre for the more expensive equipment as they charge for their own
conventional equipment.
Because of mandated state and federal licensing requirements for applying
and storing crop protectants, many farmers and small custom applicator operations
have made the decision to get out of the application business. This puts the
burden of providing equipment, chemicals and the storage of chemicals directly
on those who have chosen to remain in the custom application business. Agway is
especially concerned with handling and accuracy in applying ag chemicals and
fertilizers. One of the primary challenges for Agway is handling of ag chemicals
that must be returned from the farm (such as sprayer rinsate) to an Agway farm
center location. Ag chemical storage and containment structures can be very
expensive.
State and federal laws and mandated requirements continue to change so that
those trying to comply to the best of their ability are always shooting at a
moving target. A good example of this is Agway's dilute pesticide management
facility. It has been monitored continuously and functioned successfully as
designed since 1983. If a similar unit of the same capacity was to be built
today, the cost would be from two to three times the cost of the original
facility because of new mandated structural requirements. Inflation over the
eight year period would, of course, add even more to the cost. Agway originally
planned to build these management facilities at many locations, but now cannot
afford to do so. When rules are different from state to state it becomes very
difficult to meet competition. Agway feels that all its facilities and all its
equipment must meet the requirements of all states.
For 1991, six new injection spray units are expected to be built and
located at strategic Agway locations.
Agway Inc. is not in the equipment selling business. All equipment is
designed and specified in-house and built to Agway specifications by others, and
used at Agway locations to serve farmers.
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Evolution of the Pesticide Container
Disposal Program in Alberta
(speech)
by
C.G. Van Tee!ing and W. Inkpen
Alberta Environment
I would like to outline our present comprehensive system in Alberta. We
do have a complete system which is up and running.
In this discussion, I will indicate how we got there as well as pointing
out things that did not work. Finally, I will describe some of our still
outstanding problems, some of which I hope will be solve though information
exchange at these types of meetings.
The present system in Alberta, handles each year about 700,000 containers
made up of about 500,000 plastics and 200,000 metal containers or a million Ib
of plastic and metal.
Our system started in 1980 when one of our staff members collected loose
containers in the coulees of Southern Alberta and piled them in a snow fenced
enclosure. Within a short time farmers had started to use the site as a drop off
place for the container. During the years, 1980 to 1986, Alberta Environment
started to provide funding to the local level of government to build these sites
and periodically contracted for their clean out. There was no planned program
as the program grew incrementally. But by 1986, Alberta Environment realized
that it should not be involved and wanted to turn the program over to industry.
The present system consists of 106 sites classed as permanent. These sites
received funding of up to $10,000 per site from Alberta Environment. We
published construction standards and guidelines to ensure that the sites were
well constructed. In the design, we followed three principles namely security
ie fenced: containment, ie berms and clay or plastic liner and water control.
The province has a dry southern half where we recommended evaporation areas to
remove the projected rainfall while in the northern parts with high rainfall we
recommended roofs on the sites. At this time more than 2/3 of the sites have
been upgraded although a very small number of local levels of government ran into
siting problems. The word NIMBY describes the problem. The local level of
government can set up any number of their own temporary sites but the system
allows for clean out only from the permanent improved sites.
The sites are operated by the local level of government, either a municipal
district, a county or in some cases a regional Landfill Authority. The sites
therefor are a local responsibility and is legislated under the Public Health Act
which make the local level of government responsible for wastes generated within
their jurisdiction. The system thus operates as part of the waste stream without
any extra costs or facilities. The 106 sites are operated by 64 of these local
levels of government. The most any local government has is four sites and the
average would be one or two sites. A great deal depends on the shape of the
local unit. In cases where the farmer may have to drive greater distances we
have provided for another site.
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In our system, the farmer is responsible for triple rinsing and bringing
the empty containers to the sites. Our agriculture consists of wheat barley and
canola with an average farm size of one to two sections. We do not have a large
percentage of custom application. This means that we have to train the
individual farmer to triple rinse.
The Alberta Environment Minister has appointed the Alberta Special Waste
Management Corporation to act as program manager. The Corporation is also the
part owner of the Swan Hill Waste Treatment facility. The Corporation puts out
a tender to the private sector for the clean out of all the sites. The clean out
involves the shredding of the plastic and metal, transport to a storage location,
processing and washing the material and finally recycling.
We have one processing plant in operation operated by Wearmounth Waste
Services in Medicine Hat, Alberta. The plant is based on water washing with
carbon absorption of the pesticide material, all in one closed loop with no
discharge allowed. Another plant is on the drawing board by Newalta at Ryley,
Alberta.
The washed and processed metal is sold as #2 scrap to an Alberta scrap
dealer. They in turn will ship the material to one of two Alberta steel mills.
The steel mills have indicated that they will accept the metal as long as it
meets our 100 ppm standard and there is no odor or liquids which can be
identified a; pesticides.
However the recycling of plastic material is another matter. We funded an
early study which clearly indicated that even over prolonged extraction more and
more pesticide could be removed from the plastic. It meant that pesticides can
migrate into the plastic and that we would never be able to remove all the
contaminants from the plastic.
On the recycling of plastic, the joint industry and government consensus
in Canada is that we have three options: either into new cans, into other plastic
products or incinerations. As government policy, we are not in favour of the
incineration options for various reason. The first option of closing the loop
into new containers will require a number of years of lead time which leaves the
middle option. We have done some trails on fence posts and curb stops with the
Superwood process. We would consider geomembrane liner or other uses as long as
we could get some comfort as to the final use of the end product.
In summery, it is hard to predict how we will finally recycle the plastic
material. We recognize that some of these concepts belong in the private sector
although we are interested in ensuring that the material is handled properly in
recognition that they do contain residues.
I indicated that in the early days of the program, it was Alberta
Environment that operated the program. However that changed with the
establishment of the "the polluter must pay" and "industries being responsible
for its own wastes" concept. The Canadian industry took the position that it was
a shared responsibility. Consequently we had a two year time period where the
containers piled up on our sites. Industry did take a major step by collecting
a $1.00 surcharge per container shipped into Alberta. That meant that there was
money on the table to set up a program.
In Canada, we have the Crop Protection Institute of Canada to represent the
chemical producers. CPIC would be your equivalent to NACA.
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Starting in November 1988, CPIC collected the $1.00 per container and
places the money into a Trust Fund. I understand that the operation of the trust
fund by CPIC involves no extra staff or other costs. The money collected is to
be used to cover the operational disposal costs as well as such agreed to costs
as farmer education and research.
We recognized very early on that we needed toxicology support in areas such
as occupational health and recycling. I have been on container sites in the
middle of an Alberta summer day and there is a smell of pesticide there. Our
strategy was to bring together a number of Universities resources and set up our
toxicology support system. That system is now made up of staff from the
Universities of Guelph, Alberta and Saskatchewan. We thus have available
independent expert advice to ensure that we are operating a safe system.
A major study is currently underway by this toxicology network. We have
a $250,000 project, all paid out of the CPIC funds, made up of four components.
The first component looks at the occupation health aspect of the crews that clean
out the sites. We expect to get the first result in May. The second components
looks at the occupation health aspects of the washing and processing plants.
Thirdly we will look at the recyclers either the steel mill operators or in the
recycling plastic plants, all for occupational health. Finally, we will
investigate a number of plastic products as suitable end products for the
pesticide contaminated material.
In the program we always run up against the rhetorical question "How clean
is clean" or "What level of contamination will you accept?" Again we turned to
our toxicology support group and they have set an arbitrary standard of 100 ppm
of total pesticide. We use a standard screen of the seven most common chemicals
in Alberta including trifluralin, triallate, bromoxynil, 2-4-D, M.C.P.A.,
picloram and diclofop-methyl. We use this standard as a requirement for the
final wash processing step. The figure itself is based on WMIS standards and a
safety factor of 10. The guideline is useful in that it provides for a quality
controllable endpoint and a level at which we will class the material as
recyclable.
I have talked mainly about the Alberta program. However, I should stress
that we are part of a three provinces block where we share the same agriculture
and disposal problems. While each province, has its own infrastructure, we
freely exchange information and coordinate our programs. Looking at the three
provinces, our market now comes to nearly 2.5 million containers in total. It
is a hope that eventually we will rationalize the system so that if becomes as
efficient as possible.
In the programs early stages, we took the strategy of identifying all the
stakeholder in the program and bringing them around one table to share
information and ideas. The committee of stakeholder is made up of interested and
affected parties. It has no formal power at this stage.
The stakeholder we have around the table are:
two farmer end user
an Alberta Environment member involved in regulations and monitoring
one representative of the local municipal governments who operates the
waste streams and sites
one CPIC member
one representative of the Boards of Health who are active in the public
safety aspect
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one member of the recycling industry
one member of the regional landfill association who operate the sites
one representative of the operational agricultural staff involved in
rural agriculture.
The committee meets about every three months. It has served as an
excellent sounding board for new ideas and approaches to operational problems.
The individual members serve as informational links to their respective
organizations who continue to support the program.
Each of the above stakeholders has an important part to play in our
program. Many aspects of our system are unique to our province. But I believe
that the concept to identify your stakeholders and work them into the decision
making process makes the program work better.
Alberta Environment role is in the monitoring and regulatory areas. I have
indicated that we provided site design specifications. We also soil sample off
and on sites. We have established water wells to monitor for any off site
movement. We inspect sites three to four times a year and can take regulatory
action if sites are not operated correctly.
I would now like to touch on some problems we have faced.
We are not happy with the amount of "other than pesticide containers" waste
streams on the sites. The sites are not under our control and we are addressing
the problem though various education and training program. The presence of any
of the other wastes on the sites, increases the program costs.
Our sites grew up around the various landfills. The containers have become
associated with wastes and being just another waste stream. As a consequence,
people have taken to dropping off other wastes stream including household wastes,
industrial wastes and hazardous wastes on sites which were not planned for this
purpose. We are vigorously pursuing proper site maintenance and operation as per
our own guidelines. If sites are not operated properly we will not clean them
out and we have the legal power to take other actions to remove other wastes
streams from the sites. What I want to suggest is that you consider locating
site outside of the general waste stream.
We are still not happy with the triple rinsing done at the farm level. We
believe that the solution to our problems starts with the farmer triple rinsing.
We estimate that about 70% of can are washed. The problem has to be addressed
through education and I suppose we must be patient. Both industry, through CPIC,
and various government agencies are getting the message out. We still have a
long way to go on farmer education keeping in mind that we are dealing with more
than 50,000 farmers
We have had contractor problems. Many did not know what business they were
getting into. The first contracts were not specific and open ended as to what
was required. We both learned on the fly. Some contractor quickly left the
business but a few have survived. In the future, we will both be getting more
efficient leading to decreased costs.
In the early stages there was a lack of funding. This was solved by the
$1.00 per container surcharge.
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It took nearly three years to resolve the government vs industry
responsibility. Right now, government is still too heavily involved in the
program. We agree that all parties must have an active and supporting role in
getting the system operational. We want to help and be around the table but we
do not see our role working on the operational aspects of the program.
We have a major question mark in regards to the washing and processing
steps. We believe that washing or processing is necessary. However the current
water washing and carbon filtration may not do the job. It is old technology
which has some questions in regards to costs, efficiently and through put.
The final end products of the recycled plastic material is still not clear.
I outlined the three options. The future may be a combination of the three.
We may also take the attitude that this is an industry problem and our program
will voluntary or involuntary give it back to industry.
Perhaps this next one deserves a separate heading. It has to do with the
total costs of the program. As noted, the funds collected under the program is
currently $1.00 per container. However, it is clear now that this will not be
enough. We wont get an accurate figure until we have been in operation for two
or so years. We may be able to rationalize the system and optimize it between
provinces and thus be able to cut down costs. We need to finally close the loop
by getting rid of all the material. So we have a number of uncertainties impact
my estimated cost figures.
My best guess is that the final figure will probably be around the $1.50
per container in Canadian dollars. This is a best estimate based on some
practical experience and some future assumptions. Not all costs for example
those from CIPC or government are attributed back to the actual program. The
local levels of government do not in Alberta at present receive any funding for
their work. Also Alberta Environment has funded the site construction for an
estimate of $1.5m Can.
That brings me to the last point. The provincial government has largely
carried out the program even thought we believe in the "cradle to grave
environmental principle." We are able to turn over a functioning system at this
time to industry. Industry can and should be able to operate the system much
more efficiently and effectively and be in a better position to control the costs
which in our program seem to be rising steadily.
The program has been voluntary up the present time for all parties whether
farmer or industry. With the current legislative review in Alberta, Alberta
Environment will be gaining broad new powers in the recycling and waste
minimization areas. We are prepared to legislate the recycling of pesticide
container by all parties if that becomes necessary. We hope that industry will
take over the program in keeping with the cradle to grave environmental approach.
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Retail Fertilizer Dealer Product Containment
by
Michael F. Broder
Agricultural Engineer
National Fertilizer and Environment Research Center
Muscle Shoals, Alabama
INTRODUCTION
Environmental protection is one aspect of the ratal 1 fertilizer industry
that has become as important as the products and services the retail fertilizer
dealer supplies. This emphasis on environmental protection at the dealer level
has largely been in response to regulations being written by some States to
protect groundwater. States were given the predominant role in developing their
own groundwater protection strategies when the U.S. Congress passed amendments
to the Clean Water Act in I'W. To keep abreast of regulations being developed
and to maintain public trust, in the fertilizer and agrichemical industry,
fertilizer dealers have been called upon to take an active role in promoting the
protection of groundwater, 7M$ paper describes :.r cjf-oundwatt-" contamination one can begin to
design an environmentally sound frrtiiuer dealership, Sources of groundwater
contamination can be gn,up( r. c,-^- • ff"^e headings: water supplies, transfer
areas, and storage ^rt.ts
A poorly designed v-:
contaminants to move di^cU
supplies must be design-?-:? fr-
system.
Transfer areas (wi..-v .
from the mixer) are sites of >
if not properly contained,
runoff, are as likely to r •
mobility in water make it s;;<
in contact with rainfall. Ni
to spillage of dry ni
Storage areas a
or piping attached to tank;-
surface water and eventually
fertilizer stored under rocf >.
is in a low area orone to ~
areas that flood, however. ','•<'.
than ideal from an er-vir-jr-rsCi
i-'j ••' one H:
ipl/t Around ,-«t/
'•''>!";*' ;fi'JT, _ r 1 ;1 I f
o. faulty casing can allow
Connections to public water
33 :k siphoning into the water
rc-c'.-v: <. naoed, urH-,<;c.:d, or transferred to and
(!'. Kif.'fiia"; -piI i <• that find their way to groundwater
\orr-, -.~r'y materials, net protected from rainfall
";.-:• Inc croundwater as are Hquids. Nitrate's
, -Yt 'i.i! ° ! . learn inn from any nitrogen fertilizers
n'"' ' :/il?n^!i3ticn of ground vater has been linked
a,-* ; • - ,-cr at dealer location',.
j.-idwa^er contamination. Tanks
fw.sive f.pi!l that can pollute
..ontained in a dike. Even dry
t.r* during storms if the storage
dre not likely to be built in
1 o-' -ted in areas that are less
-------
SITE SELECTION
When choosing a site (:•• < now \- o ;!.:')>'. or : tiar^r,^ my an existing facility
the environmental suitability of the s'le should be assessed. An ideal site
should be located a safe distance froii private wells or surface water supplies.
Sites in a flood plain or with shallow groundwater depth should be avoided. Soil
bearing capacity should be sufficient to support the loads of buildings, storage
areas, and vehicle traffic. Existing drainage patterns and topography should be
studied to determine how the
off the site. A loading pad
runoff. Likewise, a wpl1
pesticide handling areas.
airborne should ba locate'!
associated with vehicle t,
should not be located in i;
• 'j\'',
are
is affected by surface water movement on and
/,,1'iiple, should not be located in the path of
o: be lj:aied down grade from fertilizer or
V-rsf'.ip handling frail-rials that can become
d 1ue to the liability
of fbrtihfe; -srd pe?tiroes, a dealership
•,i> when: traffic irooien'S
A problem facing man,-,
This is common in the tasi *r
built in rural areas. In thcv-
to relocating to a more f
upgrade of a facility
o-:; b
ir clr-,e '.,ro,., ;iri< v to urban areas.
'-jruw?< ^rai^n oual^r s~tes that were
i-r:ous cons iaer•:):<
should be consuHed whon uea
rr-a ;oiu';0 ; f
-, <,.v;- i*v '•: ir. Important
:->m past practices. Those
i.,uuetun; should consider
r.oi i sf.ould be tested to
If the- cor.taninants are a
t'ire -Jiat prevents further
rtiMt; ?:hicn do not readily
!!••*• ;:.'U •- clean-up costs
. P I
'.-a
ih
secondary
used as
i-alers in states
-., attainment
rank failure.
e "loading and
are
Wellhead Protection
The first step in making .
inspect the water source. DeA-t:
the wellhead. The concrete p?« ,
above the surrounding area to 9; .
Runoff allowed to pond arouna tile-
way to groundwater by seaping ^r.
casing. The risk associated vfii.^,
that regulations us hon.-- :,tii.-'
handling facilities wHhin '•.').'• o
Agriculture, 1989; Souln Oak:' , .
t i i environmentally secure is to
,ite w?11 should thoroughly inspect
-round the well should be elevated
-ft -i-; carried ?»viay from the well.
1 •.;,-- t,'-;.ii- the wellhead can find its
• .sine -„•- i.hrough a crack in the
-------
Frost pits are not allowed on new well installations in most states.
Dealers with a wellhead in a pit should consider extending the casing above the
surrounding soil surface. The minimum recommendation is to ensure that the pit
is water tight and that no contaminants can enter the pit. Local officials
should be contacted concerning requirements for private wells.
Abandoned wells or wells that are rarely used are common at dealer sites.
These should be retired and sealed. Generally a permit is required to close down
a well. The Cooperative Extension Service or local Public Health Office should
be contacted for details regarding well closures.
Water System Protection
All connections to the process water supply system should be inspected to
ensure that fertilizers and pesticides can not enter the water system by back
siphoning. Areas where this can occur are through the water inlet to the mix
tank or where vehicles are filled through a bottom connection. Even hoses which
have their discharge end submerged in a pool of liquid can allow material to back
siphon when there is a loss of pressure in the system. The two standard methods
for preventing back siphoning are an air break tank and a reduced pressure
principle zone (RPZ) valve.
An air break tank is merely a water supply tank which receives water from
a well or public water system through a pipe having an air space between the pipe
discharge and highest water level attainable in the top of the supply tank.
Generally, the distance between the pipe and maximum water level is two pipe
diameters. The supply tank generally provides water for the entire facility and
a pump can be used to boost pressure if the static pressure in the supply tank
is inadequate.
An RPZ valve is a special device that has two independently acting check
valves and a pressure differential relief valve located between the two check
valves. When there is a loss of pressure in the water supply the two check
valves close to prevent the flow of water from reversing and siphoning process
material into the water supply. One undesirable feature of RPZ valves is that
they may reduce line pressure by as much as 10 psi. These valves may have to be
regulated by State or local agencies and will, thus, require approval for
installation and be periodically tested and inspected.
Transfer Operation Containment
Transfer operations include loading, unloading, and other operations
involving the movement of pesticides and fertilizers. Before emphasis was placed
on groundwater protection, there was little concern over the small quantity of
material spilled when spreaders or nurse trucks were overfilled. Likewise, leaks
from valves, pump seals, and dry fertilizer conveyors were not thought to have
a detrimental effect on water supplies. At some dealer locations the
accumulation of these types of spills have not only contaminated soil but also
the groundwater. Consequently, containment for loading and mixing areas are
receiving the highest priority in many state regulations (Iowa Department of
Agriculture, 1988; South Dakota Department of Agriculture; Illinois Department
of Agriculture, 1989).
168
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Loading areas (load pads) are generally concrete pads designed to collect
spills occurring while loading tenders, spreaders, nurse equipment, and sprayers.
The main design features are; liquid holding capacity, pad length, pad width,
slope, sump location, and sump design. No single load pad design will satisfy
everyone's needs. Many pads are used for equipment washing. Pads used to wash
dirt and residues from field equipment should be large enough to catch all liquid
sprayed while washing and should have a good sediment removal system,
particularly if rinse water is intended for use in solution (clear liquid)
fertilizers. The following discussion applies to both loading pad design and
equipment wash pad design. At most locations a single pad serves both purposes.
Liquid Holding Capacity--
The liquid holding capacity of load pads should be based on the volume of
the largest tank loaded on the pad. For example, a pad used for loading large
transports should be designed to hold the entire contents of the transport,
typically 4,000 gallons (Illinois Department of Agriculture, 1989; South Dakota
Department of Agriculture, 1990). One state requires that loading pads for fluid
fertilizer have a capacity of at least 1500 gallons (Wisconsin Department of
Agriculture, 1988). Some states do not require a pad for unloading raw materials
at the site: other states require load-in pads but with volumes as small as 25
gallons (South Dakota Department of Agriculture, 1990; Illinois Department of
Agriculture, 1989). Consequently, a single pad used for loading out as well as
unloading raw materials should be sized to satisfy the requirement for load-out
pads. Since incidental spills at raw material unloading sites are common, some
containment should be provided for recovering spills.
The entire contents of the tank on a large transport vehicle can be
difficult to contain on a pad designed to accommodate one vehicle. For example,
a pad 12-feet wide and 60-feet long designed to hold 4,000 gallons of liquid,
will be 2.2 feet lower at the sump if the four edges are at the same elevation
and all slope to the sump (see figure 1). If the pad has a 12-foot long trough
in the center, the top edge of the trough would be 1.5 feet below the height of
the edges (figure 2). The steep slope of both pads would make vehicle access
difficult.
Increasing the area of the pad permits a shallower pad for a given volume.
However, a larger pad will be more likely to overflow with rainfall accumulation.
The pad in figure 1 can hold 9 inches of rain. A pad with the same volume but
twice as wide will be half as deep and will hold only 4.5 inches of rainfall.
Rainfall can only be discharged if the pad is clean before rain begins.
Otherwise, it must be handled as a dilute fertilizer or pesticide mixture. For
this reason, many dealers are building roofs over loading pads. This should be
considered in high rainfall areas.
One practical way to increase the volume of a pad is to form a roll-over
curb on the perimeter. The addition of such a curb, 4 inches high, on the pad
in figure 1 increases its volume 45 percent (see calculations under figure 1).
In some state regulations the volume requirement for the load pad can be
met using an automatic sump pump connected to a storage tank inside a secondary
containment basin (111 inois Department of Agriculture, 1989; Wisconsin Department
of Agriculture, 1988). A more reliable method for increasing the volume of a
load pad is to provide an overflow to another basin. This can be done by
elevating the load pad above a secondary containment dike. Buried tanks or pits
should not be used to store liquid from loading pads. Some states allow
169
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temporary storage of liquid from load pads (Department of Agriculture - Illinois,
1989; South Dakota, 1989; Wisconsin, 1988). Long term storage of fertilizer or
pesticides in pits or wet wells is prohibited without an approved ground water
monitoring system ( Wisconsin Department of Agriculture, 1988). Dealers using
pits or buried tanks should remove them or retire them by thoroughly cleaning
them, sealing all inlets, and filling them with sand or clay.
Pad Length and Width--
The pad dimensions should be based on the area required for work done on
the pad. A pad used for equipment washing should be a minimum of 20 feet wide.
If the pad will be used for both loading and unloading, it should be wide or long
enough to accommodate two vehicles. Dealers handling liquid fertilizer and
pesticides may need extra space for loading or unloading mini-bulk containers.
Some dealers may require space on the load pad for tanks used to store spillage
or rinsates. Experience has shown that load pads are never too large. Load pads
40 feet by 60 feet are not uncommon for fluid fertilizer/pesticide dealers.
Pads for loading dry fertilizer must be sized to collect material which
spills over the sides of spreaders or tenders. Experience has shown that the pad
should extend about 10 feet beyond each side of vehicles being loaded with the
elevation of the edges of the pad being about 4 inches above the center. Pads
for dry materials have no volume requirement. A gravity drain with a lockable
shut-off valve can be installed to discharge snow melt or rain free of fertilizer
and pesticide residues. As in liquid operations, rainfall accumulation
contaminated with fertilizer must be handled as a dilute fertilizer/pesticide
mixture. Most problems associated with rainfall and snow can be eliminated by
building a roof over the load pad.
Spills occurring while filling dry fertilizer bins should also be collected
and kept away from rainfall. Some dealers place the boot of portable augers
inside a large tray to collect spillage. The most common type of containment
around these areas is a concrete pad that facilitates the manual collection of
spilled material. Railcar unloading areas are a problem to keep clean. The best
way to keep the area between the tracks clean is to pave the area and slope the
pavement away from the conveyor. A water tight lid should be placed over the
conveyor to keep rain water out of the conveyor. This is critical if the bottom
of the conveyor is not sealed to prevent water from leaking out, carrying
fertilizer nutrients downward.
Liquid railcar unloading sites have been contained by paving the area
between the tracks and sloping the pavement to a point where a tie can be removed
permitting liquid to flow under one rail and into a basin where it can either be
used as make-up water or, if free of contaminants, discharged. There are
prefabricated pans made of fiberglass reinforced plastic that can be installed
between and on both sides of the rails for collecting liquid spills. These
prefabricated pans are sloped to built-in sumps which facilitate the recovery of
spilled material. Portable pans can be used to collect small spills at rail
sidings, however, catastrophic spills are difficult to contain.
One method for containing large spills at liquid railcar loading areas is
to install a synthetic liner in the gravel beneath the tracks. The liner can be
extended away from the tracks and sloped to a sump for recovering liquid.
170
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Few dealers have installed spill containment systems for railcar loading
and unloading areas and state regulations have not addressed this problem. As
containment technology and regulations progress, more methods for containing
spills at rail sidings should be developed.
Pad SI ope--
The slope of loading pads should be a minimum of 2 percent. Concrete
surfaces which come in frequent contact with fertilizers or pesticides should be
sloped 2 percent to minimize the corrosive effect of these materials and to
facilitate the washing down of the pad (Noyes, 1989). This slope is preferred
over shallower slopes because it reduces the chance for errors in finishing that
will cause liquid to puddle on the pad after being drained.
Sump Location--
The location of the sump depends on how it is used and how vehicles travel
on the pad. If the pad is to be accessible from all four sides, then the sump
should be near the center of the pad. A sump located in the center of the pad
can interfere with the movement of product if the sump has to cleaned out or
manually pumped out while product is being loaded. For this reason sumps are
often located on one side of the pad. This still permits vehicle access from
three sides. Some dealers have a sump in the middle of the pad and a deeper sump
on the side. The two are connected by a trough or a pipe that runs beneath the
pad. The sump in the middle of the pad traps solids while liquid is pumped from
the second sump.
Sump Design--
Sump designs vary considerably in terms of how they are used to handle
solids. Suspension dealers who can handle solids in their products have simple
sumps and pump all the sediment directly into applicators. A screen either over
the sump or the pump inlet is used to remove rocks, cigarette butts and other
debris. Other dealers go to great length to separate all solids from liquid
being recycled. These dealers either use an extra sump for solids removal or use
a sediment trap around their sump. Figure 3 shows a typical concrete sump with
a perimeter sediment trap. Some dealers slope the sediment trap to one side to
decrease the area where solids settle. Sediment traps must be cleaned
periodically to keep sediment from overflowing into the main sump from where
liquid is pumped. Figure 4 shows a pad with two sumps. A pan can be fabricated
to fit beneath the discharge of the higher sump. Solids can then be removed by
dumping the pan. Dealers not equipped to handle sediment in sumps should realize
that this material may be too contaminated to discard as dirt. Experience has
shown that, where pesticides are handled, sediment collected in sumps can destroy
vegetation. The two approaches for handling these solids is to slurry them into
a liquid mix or dry them and add them to dry fertilizer, being careful to apply
the material on crops not subject to injury from the contaminants and at rates
at or below that specified on product labels.
The labor associated with forming and pouring a concrete sump can be
avoided using prefabricated sumps. Stainless steel sumps are usually double
walled with ports on top to permit leak detection between the walls. Stainless
steel sumps can be fabricated in any size, however, most have a capacity of about
30 gallons.
Precast-concrete sumps can be custom built in a range of sizes and with
fittings to accept piping connected to other load-pads and operational areas.
At large facilities recycling of rinsates can be simplified by collecting
171
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material in a common sump. Pipe inlets should be above the bottom of the sump
so that liquid can be pumped to a level below the inlets. This reduces the
chance for liquid to leak into the ground around pipe inlets. Concrete sumps
usually have a capacity of about 100 gallons. Some dealers prefer a large sump
and sediment collection system to increase the time between clean-out. If
pesticides are rinsed or handled on the pad, a large sump is undesirable because
of the problems associated with contamination. For example, if a dealer switches
from corn to soybean herbicides, he has to completely clean the sump to avoid
contaminating his soybean make-up water with corn herbicide residues. The
simplest way to avoid contamination of herbicides is to use a small sump that is
cleaned daily or more often if needed to purge the system. Sumps in areas not
protected from rainfall should be kept clean to permit the unrestricted use or
discharge of collected rain water.
There are alternatives for segregating rinsates other than cleaning out the
pad and sump. One is to divide the load pad into two or more areas by sloping
sections of the pad to different sumps. Another alternative is to slope the pad
to a wall where multiple drains with valves are used to direct spills and rinsate
into a particular sump. Each sump has a dedicated pump and rinsate storage tank.
This system is ideal for locations where rinsate segregation is important.
A trend in the industry is to add pesticides to fertilizer products in the
applicator in the field and rinse the applicator in the field. This practically
eliminates the need to segregate rinsates because they will normally not contain
pesticides. This management practice permits the use of one rinsate tank.
Other management practices which enhance the environmental security of a
dealership will be discussed later.
Mixing Area Containment
Mixing areas are the site of incidental spills that require containment.
A variety of materials are handled in the mixing area. Spills occur when
materials are manually added to the mixer. Piping systems and conveyors for dry
materials often leak. Consequently, mixing areas are as important as loading
areas with regard to containment.
Liquid Mixing Areas--
Containment for the liquid mixing area usually involves installing a curb
along the inside wall of the mix house. The containment volume should be equal
to the volume of the mix tank. At several locations the mixing area has been
contained by allowing the area to drain onto the loading pad and installing a
curb on the inside of the other three walls of the mix house. Figure 5
illustrates how a curb can be built on an existing slab. At some sites the mixer
has been moved to one corner of the load pad. Combining the mixing containment
and load pad is common because they are usually adjacent and both receive all the
products handled at the facility.
Since it is desirable to keep fertilizer containment areas free of
pesticides, areas where pesticides are mixed should not be allowed to drain into
the fertilizer containment. Mixing area containment should be large enough to
accommodate mini-bulk containers and other portable pesticide containers that are
not located in a secondary containment dike. When combining containment areas
it is sometimes desirable to segregate different areas inside smaller dikes to
keep incidental spills isolated. For example, a pump that leaks or a place where
hose connections are frequently made, can be contained in a pan or inside a
172
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separate curb. Confining frequent spills to a small area can reduce the amount
of rainfall that becomes contaminated and must be handled as dilute product.
Piping from storage tanks to the mixer and to the load pad should also be
contained. At most facilities, these areas are connected and the piping is
always above a contained area or over the load pad. Piping used to transfer full
strength materials should not be buried underground without being placed inside
a larger pipe. The larger pipe can be sloped so that leaks in the inside pipe
will flow to one end of the piping system where leaks can be contained and
detected. Buried pipes are acceptable for transferring rinsate or material
collected in sumps to a larger sump or to a rinsate holding tank.
Dry Mixing Areas--
Dry fertilizer mixing areas are best contained under roof. Several dealers
have extended the roof of their dry fertilizer storage building to include their
blender and load-out conveyor. Others have kept their blender inside the storage
building and have built a concrete pad to collect material which falls beneath
the conveyor as well as material spilling over the side of spreaders and tenders.
The latter approach has been taken in the Great Plains where annual rainfall
amounts are below 20 inches.
Blending towers, blending systems having a cluster hopper, weigh hopper,
and blender stacked vertically in a tower, should be enclosed and have a roof
over the loading area. If the tower is not enclosed, the pad beneath the tower
should be large enough to catch leaks in the blending system as well as material
spilling over the sides of spreaders and tenders.
Facilities where dry fertilizers are impregnated with herbicides must have
containment for confining pesticide spills in a manner to prevent contamination
of fertilizer raw materials. The impregnation operation and load-out should be
under roof, otherwise, rainfall coming in contact with pesticide residues in the
blender or conveying system must be collected and handled as a dilute
pesticide/fertilizer mixture. Spilled material and product cleaned out of the
blender should be stored inside and added in small proportions to blends.
Pesticide concentrations may be too high in this material to permit it to be
directly applied. If water is used to clean the blender, it must be treated as
a dilute pesticide. Dealers without liquid application equipment may not want
to use water to decontaminate their blender. Limestone or potash can be used to
purge the system of pesticides. This fertilizer-pesticide mixture should then
be applied on crops in accordance with the labels of the pesticides contained in
the mixture.
Storage Area Containment
When dealing with liquid products, storage area containment involves
secondary containment, a dike or basin which holds the material if the primary
containment (storage tank) fails. The major difference in secondary containment
for fertilizers and pesticides is the construction material. Earthen dikes are
allowed for fertilizer secondary containment and are not permitted for pesticides
(Illinois Department of Agriculture, 1989). When dealing with dry fertilizer,
containment involves storing material in a building that has a roof, walls, and
floor that prevents fertilizer from coming in contact with precipitation and
surface water.
173
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Liquid Fertilizer Savage CunM'nm.:v> •
Secondary containment for 1-ouid fertilizer consists of a basin with a
floor and walls that, are essentially '^pervious to liquids. The basin is usually
sloped to a sump where liquid can be pumped to a holding tank or discharged is
not contaminated. The volume of the secondary containment, excluding the space
taken up by tanks, must be at. least 110 or 125 percent of the volume of largest
tank in the containment (Departments of Agri'jUure - Iowa, 1988; South Dakota,
1989; Wisconsin, 1988; Minnesota, <989). Th=* percentage varies by state and one
state requires that the secondar,? containment hold 6 inches of rain in addition
to the volume of the largest tanK (rinnoir> Department of Agriculture, 1989).
The following discussion deals with secondary containment for tanks, not in-
ground pits with flexible liners. In-ground pits are not permitted for primary
containment of fertilizers or pesticide; in most states. If allowed, pits will
be regulated as underground storage tanks and must be double-lined and have a
means to check leaks in the primary liner. In-ground systems are well suited for
secondary containment. This application will be discussed later. Local
regulatory officials should be contacted by dealers considering pits for primary
storage.
In secondary containment 'iy3>.r:"\., pic-im;: runs should be over and not
through the containment w;.]'. i: cu'i:^} if-=: pass through a containment wall,
care should be taken to get a good 1,1},,;' necween the pipe and wall. The
structural integrity uf the will :.:-..-:=j''.i oft hs compromised nor should the liquid
holding capacity.
Rain accurcu?3i:;'.n :,b?ukl r,t j,: unseen out with a manually controlled pump.
Drains should only be us?d w':h a locxable valve that is strictly managed to
prevent the inadvertent release of tufitarmnared water or fertilizer (South Dakota
Department of Agriculture, ]989;. 1.1 some states, drains are prohibited
(Department of Agriculture - icwa, 1988; Illinois, 3989).
Sight gages used to monitor liquid levels in tanks are a source of
liability because they are easily damaged or broken, releasing the contents of
the tank. Sight gages should only be used if a stainless steel valve which is
normally closed is installed between the Dottom of the sight gage and the tank.
The most difficult aspect of retrofitting secondary containment at a
facility is selecting dimension^ mat «il; conserve space without impeding
vehicle and employee access, u. the uanks. A •ypica] facility has tanks grouped
in one or more clusiers. If possible, tanks should be consolidated in one
cluster. This usually minimi?ac> the raquired wall height since the volume of the
containment is based on the largest Dingle tank. Providing adequate space between
tanks will also decrease wall height. Spacing tanks close together will minimize
floor area, but will increase wal1 height. In general, 36 inches is the highest
practical height for secondary containment walls, even though higher walls can
result in a less expensive design due tc the reduction in floor area. Higher
walls impede employee access, increase problems associated with tanks floating,
and expose employees to more risk, while inside the wall.
The first st&p in sizing a secondary containment is to determine the
required volume. Then t scaled drawing of the plan view of the tanks and
containment should be made. The net containment area should be determined by
subtracting the area of all but the u^qesr tank from the total containment area.
The height of the containment •»«;] is 'Vti'tTisned by dividing the required volume
by the net containment area. If the contamnent wall is higher than desired the
1/4
-------
containment area should be enlarged. For example:
Assume a containment for Pour 25,000-qallon tanks is desired. All tanks
are 12 feet in diameter, have flat bottoms., and are 29 feet high. The
containment floor dimensions are 20 feet by 50 feet. Containment volume
must be 110 percent of the largest tank,
Required volume (RV) in cubic feet
RV = LTV x FF / 7.5
Where,
LTV = Largest tank volume in gallons
FF = Freeboard Factor, 1.1 for 110% or 1.25 for 125%
7.5 = gallons per cubic feet
For this example,
RV = 25,000 gal x 1.10 / 7.5 gal/cubic ft
RV = 3,667 cubic ft
Net containment area (NCA) in square feet
NCA = Total area - tank area
NCA = (20 x 60) - (3 x 113)
NCA = 1200 - 339 sq ft
NCA =861 sq ft
Note: The area of only 3 tanks was subtracted since the spilled liquid
will occupy space in the leaking tank.
Wall height (WH) in feet,
WH = RV/NCT = 4.3 ft
The required wall height for this design is 4.3 feet or 52 inches. The
floor area should probably be increased to decrease the wall height.
Tanks should be anchored to prevent them from floating when empty. The
concern is that other tanks in the containment can lose product from damaged
plumbing or can rupture from collisions with the floating tank. The simplest way
to anchor tanks is to weld three or mor? brackets to the tank where the sides
meet the floor. Each bracket is then bolted to the concrete with anchoring
bolts. Chains and tie-down cables can be used with brackets welded above the
tank bottom. In clay-lined earthen dikes, weights can be added to the tanks or
cables can be used to secure the tank to anchors outside the dike. Anchors in
the soil beneath the liner or cables connected to concrete deadmen can be used
if the area where the liner is penetrated is properly sealed. Anchoring of tanks
is a practice often neglected when tanks are placed in secondary containments.
The following example should illustrate the importance of anchoring tanks.
A typical carbon steel tank, 12-feet in diameter and 29 feet high, holds
25,000 gallons of liquid and weighs about 13,000 pounds when empty. An
inch of ammonium polyphosphate solution in the tank weighs 825 pounds.
Sixteen inches of material in the tank weighs about 13,000 pounds.
Exceeding this same level of solution outside the tank will cause the tank
to float when empty. If a 36-inch-high containment were full of solution
the buoyancy force pushing upward on the empty tank would be the same as
20 inches of solution in the tank or 16,500 pounds. Shorter tanks of the
175
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same diameter weigh less and would float in a shallower depth of liquid.
Stainless steel tanks weigh slightly less than carbon steel tanks of the
same size and fiberglass and some polyolifin tanks are considerably
lighter.
Another design consideration of secondary containment is the method for
leveling tanks on a sloped containment floor. Containment floors should be
sloped to minimize the corrosive effects of fertilizer on the floor and to ensure
proper drainage. Concrete floors should be sloped a minimum of 2 percent. The
simplest way to level the tanks is to place them in a metal ring filled with
coarse, washed gravel. In addition to providing a level surface for the tank,
the gravel provides a space for detecting leaks and keeps moisture away from the
tank bottom, thus prolonging the tank life by reducing corrosion. The objection
some dealers have with gravel is the difficulty in cleaning the gravel after a
spill. The quality of rain water could be adversely affected long after a spill
has been recovered.
An alternate method for leveling tanks is to pour raised concrete pads
beneath each tank. This is most easily done by pouring the tank foundations
first and making a second pour for the space between tanks. This is not the
preferred method of construction because of the sealing required around tank
foundations. The best method is to make the sloped and level surfaces in one
pour. The second best approach is to pour the entire bottom of the pad and use
dowels to attach the tank foundations made in a second pour. Many dealers have
had success with level secondary containment floors with tanks setting directly
on the floor. The key to their success is attributed to keeping the floor dry
and free of fertilizer.
The most common construction material for secondary containment is
reinforced concrete. The major considerations are that the walls and floor be
strong enough to support the gravity loads of the tank and the hydrostatic loads
of a massive spill with a minimum amount of cracking. It is also important to
provide a watertight seal between the floor and wall connection. Figure 6 shows
a typical concrete containment floor and wall construction. Figure 7 shows a
containment wall on a floating slab. Floating slabs are common in colder areas
where frost depths are such that deep footings are required. A typical secondary
containment showing tank foundations and anchors (Kammel et al. 1990) is shown
in figure 8.
Dealers not experienced in water-tight concrete construction should secure
the services of a qualified contractor. A brief summary of recommended concrete
specifications is given in a another section.
Concrete block can be used for secondary containment walls. To withstand
the hydrostatic forces of liquids, block walls must be reinforced with steel and
filled with concrete. Some type of sealer should also be used since concrete
blocks are not watertight.
Large Tank Containment--
Designing secondary containment for tanks with capacities over 100,000
gallons presents some engineering challenges. These tanks are usually built on
sand, providing no barrier to downward movement of leaking material. They cannot
be raised with a crane and placed inside a containment. Many dealerships lack
adequate space to build a secondary containment dike for these large tanks.
State regulations regarding large tanks vary. Proposed methods for containing
176
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these tanks are so varied, one state issues experimental permits for designs not
explicitly defined in the regulations (111inois Department of Agriculture, 1989).
In new installations the tank can be built within a concrete containment
or some other watertight basin. The aim is to be able to detect leaks in the
tank inside the containment. Providing some type of impervious barrier beneath
existing tanks is a problem with no simple solution. The most common method for
detecting leaks is a false bottom. A false bottom is a steel floor welded inside
the tank over a thin layer of sand (Figure 9). If the tank has a sump, it is cut
out and a steel plate is welded in its place. A layer of sand is placed over the
old tank floor. There are two methods for attaching the new floor over the layer
of sand. One involves sliding steel sheets for the new floor through slits cut
in the wall just above the sand. The steel plate is welded to the wall and when
the new floor is complete the slit circles the entire wall separating the old
bottom from the tank. The old bottom merely becomes a shallow pan full of sand.
Some contractors weld the old bottom to the edge of the false bottom and install
leak detection ports in the sand layer.
The other method for attaching the false bottom to the tank wall involves
the use of an angle iron which is bent to match the curvature of the wall. The
angle is welded to the wall and provides a surface on which to attach the new
floor. Steel sheets for the new bottom are delivered through a large opening cut
in the the top of the tank.
The area around the tank is usually sealed with a clay lined earthen dike.
Clay lined earthen dikes are made by uniformly incorporating bentonite or
attapulgite clay into the top 6 inches of soil. Large rocks and gravel must be
removed as well as soil high in organic matter. A thorough analysis of the soil
is required to determine the amount of clay required per square foot of soil.
An engineering recommendation or the recommendation of the appropriate regulatory
agency should be followed concerning clay addition. In most state regulations,
the maximum permeability is one-millionth centimeters per second (one-third of
an inch per day). The clay seal should cover the area inside the dike and up to
the top of the dike (Figure 10). The top of the dike should be three feet wide
and the sides should slope no more than one foot per two feet of run. A six-inch
layer of gravel or soil should be placed over the clay liner to protect it from
erosion and desiccation.
Natural soil can be used for an earthen dike without the addition of clay
if the soil has the following physical properties; 50 percent or more of the soil
passes through a No. 200 sieve and no more than 5 percent is retained on a No.
4 sieve. The soil must also contain less than 2 percent organic matter and have
a plasticity index of at least 15 (Wisconsin Department of Agriculture, 1988).
Synthetic liners are an alternative to clay liners. Sheets of synthetic
liner material are bonded to form a solid barrier inside the containment. The
walls and floor of the basin can be made of packed earth or the floor can be
earthen with walls made of concrete or prefabricated panels bolted together and
anchored in concrete. Properly installed, synthetic liners are available with
a guaranteed service life of 20 years. The disadvantage of clay and synthetic
liners is the problem associated with cleaning up a spill. Their advantage is
their lower cost compared to concrete or steel.
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Some large tanks have been contained in a large steel tub to conserve
space. The idea is bizarre but not as impractical as it sounds when one
considers that a million gallon tank requires a dike over an acre in size if the
walls are 3 feet high. The steel containment, coined the elephant ring, for a
million gallon tank occupies an area smaller than one-fifth acre. An elephant
ring is typically half as deep as the tank is high. With this ratio in height,
110 percent of the tank can be contained in a tub having a diameter 1.5 times
that of the tank. A tub diameter 1.6 times that of the tank will contain 125
percent of the tank. The tank and tub combined require nearly twice as much
steel plate to build as does the tank. The walls of the ring must be reinforced
with members attached to the tank and the tank should rest on a 2 to 4 inch layer
of gravel or sand to reduce corrosion and for leak detection. As with other
secondary containments, rainwater has to be dealt with. A variation of the
elephant ring that eliminates rain water problems is a ring that has a radius
about 4 feet larger than the tank radius with a roof over the space between the
tank and ring. This system has been proposed but has not yet been built.
Though large tanks are not easily moved, there are some methods for moving
large tanks into a containment basin, eliminating the need for a false bottom
that is costly compared to a synthetic or a clay liner. Since large tanks are
easily damaged, an engineer or experienced contractor should be contacted for
assistance in moving them. Large tanks have been moved by floating them in
water. Some of these tanks are made primarily of steel only three-sixteenths of
an inch thick and will float in water no deeper than 10 inches. A clay lined
dike is built around the tank and water is pumped into the dike until the tank
begins to float. It is then moved to a clay lined area in the dike. Water is
pumped or drained out of the dike and the area where the tank was previously
located is then sealed with clay. To reduce the chance of damaging the tank,
projections, such as the sump should be removed. Interior braces may be required
to support the bottom against the buoyant forces of the water.
Tanks as large as 300,000 gallons have been moved by the same method as
houses are moved. Two large beams which pass through holes cut in the in the
tank wall are used to support the weight of the tank while being moved. After
moving the tank, the holes must be patched and tested for leaks.
Four tanks in Nebraska were moved two miles using three dollies made from
semitrailer axles. The dollies consisted of a framework that bolted to brackets
welded to the side of the tank. Hydraulic jacks on the dollies were operated
simultaneously to raise each tank. One of the three dollies had a fifth wheel
that allowed a tractor to pull the tanks.
A fourth way to move large tanks is on a cushion of air. This involves
attaching a skirt around the bottom of the tank and using large blowers welded
to the tank to provide a cushion of air on which the tank can ride while being
pulled on a relatively smooth surface.
Another alternative to false bottoms for leak detection involves subsurface
drainage that spills into a sump or containment basin around the tank. Equipment
used by utility companies to bore under roads can be used. The containment would
resemble a moat with perforated piping discharging into a moat. Someone
specializing in subsurface drainage should be consulted to determine the
suitability of the site for this type of leak detection.
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Large tanks must also be anchored. Weights can be attached to the tank or
tanks can be constrained using cables attached to anchors outside of the dike
(Kammel et a!. 1990). Concrete deadmen or earth anchors can be placed beneath
the liner if the clay or synthetic liner is properly sealed. Since the bouyant
force on a large tank can exceed 100,000 pounds, an alternate method to protect
the tank and dike is to constrain the tank from lateral movement while allowing
it to float. Flexible plumbing is required to allow the tank to move without
damaging plumbing. It is also a good practice to leave fittings and manholes
open when tanks are empty to equalize liquid levels inside and outside the tank
in the event of a spill or rainfall accumulation.
Pesticide Storage Containment--
Pesticide storage containment is similar to fertilizer storage containment
with the exception of earthen containments which are not permitted for
pesticides. It is also important to separate pesticide containment from
fertilizer containment. The two can be adjacent inside one containment area with
a dividing wall between the two. The dividing wall can be lower than the outside
wall to allow the whole area to be used as one containment during a catastrophe.
Pesticides should also be kept under roof because of the problems associated with
contaminated rain water. Packaged pesticides should be stored in a separate
warehouse and not inside a secondary containment for bulk pesticides or
fertilizer. Flammable pesticides should be separated from non flammable ones and
the warehouse should be curbed to contain large spills or water used in
extinguishing fires.
Dry Fertilizer Storage Containment--
Dry fertilizer storage buildings should be elevated above ground level to
prevent rainfall runoff from entering the building. The floor should be paved
with concrete and cracks should be routinely repaired to prevent the downward
movement of fertilizers. The roof and walls should be free of leaks that will
allow rain water to come in contact with fertilizer. Floor sweepings and scrap
fertilizer materials should be kept under roof as are other dry fertilizers.
Limestone is generally the only dry fertilizer material that can be stored
outside.
Until recently, wood was the material of choice for dry fertilizer
buildings. Some new buildings are being made primarily of reinforced concrete.
The floor is poured with slots wide enough for walls to be stood edgewise in
them. Wall sections are then poured horizontally on the floor. Reinforcement
steel and clips for connecting wall sections are accurately placed in each wall
section. A crane is then used to erect the walls and connect adjoining panels.
The bin walls are supported laterally across the top of the open end with steel
or concrete beams. The advantage to this type construction is the savings in
labor compared to wooden buildings.
WATER-TIGHT CONCRETE CONSTRUCTION
To ensure that concrete for load pads and containment structures will
resist penetration by moisture and chemicals and have a durable finish, the
following specifications should be followed (Noyes, 1988):
Use Type IIA or Type II cement with air entrainment at 4,000-4,500 psi
compressive strength. Type II provides moderate sulfate resistance.
179
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Use water-cement ratio of 0.40-0.45 for a stiff (1.5"-3" slump),
relatively dry mix for maximum strength, chemical resistance, freeze/thaw
resistance, and watertightness.
Use 5.5% to 7% air-entrainment in cement to improve workability at
placement, and improve watertightness and strength of low slump concrete.
Use concrete plasticity admixture for easier workability at placement and
for improved watertightness and strength.
Vibrate concrete during placement at 5,000 to 15,000 vibrations per minute
for minimum aggregate segregation.
Powered steel trowel surface finish to minimize coarse surface texture to
improve washing and cleanup.
Immersion or moist cure concrete at least 14 days (28 day immersion or
moist cure preferred for maximum strength).
Allow no more than 30 minutes between concrete truck loads during
placement.
Mix concrete 70-100 revolutions at mixing speed, then an additional 200-
230 revolutions (maximum of 300 total revolutions) at agitating speed.
Discharge mixed concrete within 1.5 hr per ACI C94.
Minimize discharge drop distance by using a discharge chute.
Use large (1" - 1.5"), clean, impervious aggregate or aggregate 1/3 the
size of the slab thickness for maximum strength and watertightness.
Use clean, drinkable mixing water at a pH - 5.0 - 7.0.
Oven test aggregate for excess moisture and adjust water added
accordingly. If oven testing is not possible, reduce total added water
assuming 3.5% excess water in sand and 1.5% excess in aggregate.
Continuous pour in one day - no cold joints.
Expansion joints should be spaced close enough to prevent cracks from
forming in undesirable places. Joints should be machine cut to a depth of one-
fourth to one-fifth the slab thickness. The rule of thumb is that the minimum
joint spacing in feet be 2.5 times the slab thickness in inches. That is, a 8-
inch slab should have joints no farther than 20 feet apart. Joints should be
located in areas where they can be monitored, for example, not under a tank.
Joints should be sealed with a material resistant to fertilizers and pesticides
and should be periodically checked for repair or replacement. The sections
between joints should be square. If not square the length-to- width ratio should
not exceed 1.5.
A vapor barrier should not be used beneath pours as this may cause the
concrete to retain moisture and increase degradation of the concrete from
freezing and thawing.
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Frost heave problems can be reduced by keeping the area around concrete
slabs dry. The area beneath the concrete should be higher than the surrounding
area and surface drainage should be provided to keep water from standing near
containment structures. The drainage around concrete structures should be
monitored for two or three years after construction to ensure that the area is
well drained after the structure settles. Runoff from buildings and paved areas
should be kept away from containment sites using curbs and gutters.
Steel reinforcement bars are recommended for containment structures. Wire
mesh or fiber additives will not provide resistance to cracking over the life of
the facility. Generally, No. 4 reinforcement rod is required and spaced 12
inches in both horizontal directions. The steel in sumps is usually spaced 6
inches. Since steel reinforcement requirements vary with soil bearing capacity,
strength of concrete, and the anticipated loads, an engineering recommendation
should be followed regarding steel requirements.
To prevent secondary containment basins from leaking beneath the
containment wall, waterstops are needed between containment floors and walls.
Molded vinyl waterstops are available in several shapes. These must be embedded
in the concrete floor beneath the wall. Other water stops are available which
can be placed on the perimeter of the slab after it has cured.
Many fertilizer and pesticide handling facilities have concrete slabs
beneath tanks that may be incorporated into a secondary containment design by
attaching walls. The suitability of the slab for supporting the wall should be
determined. In most instances this is not the case. If the concrete is in good
condition and free from cracks it can serve as part of the containment floor and
the pad can be extended. The wall can then be built above new concrete. It is
important when joining new concrete to old concrete to seal the crack between the
two slabs and to connect the slabs using dowels inserted into holes drilled into
the existing concrete. In some instances even where existing concrete is in good
condition the best decision is to remove the concrete if the slope is incorrect
or the pad is too low due to settling. An engineer experienced in concrete
design should be consulted regarding the use of existing concrete.
MANAGEMENT PRACTICES
Containment systems are an essential part of environmental security at
fertilizer/pesticide dealerships, but they are no substitute for good management.
Environmental management involves, 1) the proper handling of fertilizers and
pesticides, 2) the security of the facility during periods of nonoperation, and
3) the reliability of equipment designed to transport or contain these materials.
Proper handling of materials begins with employee training and education.
Employees should understand the sources of groundwater contamination and the
importance of keeping fertilizer and pesticides contained. The rinsate storage
scheme should be understood by all and all storage containers should be labeled,
including rinsate containers. A typical scheme may involve rinsate storage tanks
designated as corn, cotton, soybean, and pesticide free make-up water. Schemes
vary according to the variety of crops treated and the amount of rinsate that is
handled at the facility. To prevent contamination of materials, spills should
be cleaned up immediately after they occur. To minimize the amount of rainwater
that must be collected and used, the loading pad and containment system should
be cleaned and sumps should be pumped out at the end of each working day or prior
181
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to rainfall even*->. ' - heip (ir'i-r^ir.* if water is suitable for discharge kits
are now beinc; marketer to i >st. liouids for contaminants. Some tests can be
completed in a few minutes, '?fh::r-s require a few hours.
There are two app: Oidv-3 re pesticide handling; mixing pesticides to the
carrier in the batch mixer and mixing pesticide with carrier at the application
site. Mixing pesticide and Carrier at tht1 facility is the common practice. This
practice ensures f o^rsulrilcn accur.icy because an experienced mixer operator
oversees the additiji of pest cides to the mix. This approach also requires less
equipment si no:; pesticides are not mixed ana handled in equipment separate from
fertilizer. The di '.advantage of mixing pesticides and fertilizers at the
facility is the amount cJ' equipment that has to be cleaned to prevent
contamination when jwit.cfr, r-y products. The mix tank, nurse equipment, and
application equiw.ie.Vr must .-•».!! be cleaned to purge the system of a particular
mater i a1. Another c!*s-v;lv;8 apn'i--<;iu>' *- rinsed in the field. On-board rinse systems are
available which have m>22.'>?s mounted inside the applicator tank to clean the tank
walls s no baff;=s, PU; t^bie sprayers are also available for cleaning pesticide
residues fror.i the outside of applicators. To ensure formulation accuracy some
operators weigh or !iH?'rer out batches of pesticide at the facility for each load
of fertilizer "-.-:•& pesticide is then transported to the field in separate
containers on nurse equipment. The containers should be approved by the
Department of fransp'Vtat ion for transporting pesticides.
Applicators can be equipped with en-board injection or impregnation systems.
These systems add pesticide to fertilizer in the output stream of the applicator.
These systems are ideal for reducing rinsate since pesticide never enters the
applicator tank. Direct injection and impregnation systems, however, are limited
in the number of products ihey ''an handle and some dealers are skeptical of their
accuracy
dSS o: wh^r-?. oecticides and fertilizers are mixed, the amount of
rinse water bandied at the facility can be reduced by rinsing as much equipment
as possible in the field. To reduce the chance for rinsates to enter surface
water ihe rinsing should ;/e done a safe distance from ditches and creeks. When
on-board rinse systems are used, the rinsate left in the applicator should be
broadcast over the f'-eld last treated. Csood judgement should be exercised to
maintain the total pesticide application rate within label recommendations.
Other method-", for VO-IIK:! ,M the vc/ jnse and cost associated with handling
rinsates include (oicder df.d L,O!SS J987):
Job scheJ.jiirvj. for oxarnple, :? dealer who plans to apply fertilizer and
herbicide t;> corn ana cotton can group the jobs so that equipment must
only be rinsed only onci> per day.
Equipment c«ifi be mod • f • -HI to reouce the amount of residue remaining after
being emptied, hv> punu! on iarne application equipment, for example, is
driven by 3 b*L >r(m chc engiue and is nearly 10 feet from the tank
drain. As <;n opt. on, *,ne purr.p can be driven hydraul ically and placed
directly beno-.it h ^he applicator tank.
-------
Using high-pressure rinse equipment can also reduce the volume of rinsate
reduced. Though centrifugal pumps are well suited for handling liquid
fertilizer, their high output and low operating pressure make them poorly
suited for washing out equipment. High pressure washers do a better job
of cleaning for the amount of water used.
Proper equipment calibration and accurate measurement of the acreage to be
applied will minimize the amount of pesticide that must be rinsed out of
the applicator or hauled back for recycling.
The security of the facility during periods of nonoperation requires daily
inspections of the security system, closing of valves, and disabling of pumps and
electrical circuits. Facilities in areas subject to theft or vandalism must have
a security fence with locks on gates around the property or should have the area
patrolled. At the end of each working day the facility should be locked and
valves on tanks and all pumps should be turned off. Some facilities are equipped
with a single switch which locks out all electrical circuits to pumps or
electrically driven valves.
Facilities in areas not subject to vandalism may not require a security
fence, however, all valves on tanks should be locked in the closed position.
Since valves on tanks and valves at the bottom of external sight gages both need
to be locked, the two can be positioned on each tank so that a single lock can
be used to lock both valves. Gravity drains on containment areas are not
recommended, however, in some areas drains are permitted to discharge rain water.
The discharge of rainwater must be closely supervised and drain valves should
otherwise be locked at all times. During extended periods of nonoperation
storage areas and containment systems should be checked frequently. Prior to the
winter season the facility should be "winterized". Water trapped in lines should
be discharged and water in containment basins should be removed to prevent damage
to the system due to freezing.
The integrity of containment systems, storage containers, and other
equipment designed to keep fertilizer and pesticides from entering water supplies
should be checked frequently. Tanks, valves, and piping systems should be
frequently checked for leaks. In some proposed regulations, a considerable
number of inspections of these systems with documentation of inspections is
required. This practice is recommended as a part of an overall inspection and
maintenance program for the facility. Tanks and plumbing, for example, should
be inspected annually for leaks and trouble areas should be physically tested by
either a vacuum or pressure test. A strict maintenance schedule should be
followed, not only to protect water supplies, but to reduce down-time during the
season.
COST AND WORK SCHEDULING
Containment of materials at fertilizer dealerships can be a costly
proposition. A concrete slab can usually be poured for about $100 per cubic
yard. A survey of dealers in the Midwest and Great Plains has shown that the
cost for loading pads, including site preparation, reinforcement, form work, and
finishing has ranged from $140 to $200 per cubic yard of concrete. This high
cost was due, in part, to the special requirements for retrofitting new and
existing concrete, site preparation, and the labor associated with forming sumps.
Other costs associated with a load pad include the cost of rinsate holding tanks
183
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and pumps and plumbing to transfer material to and from these tanks. At most
facilities, three or four 500-gallon tanks are needed. The total cost for a
rinsate recycling system should be around $2500, depending on the amount of
material that must be purchased.
The cost of secondary containment will depend on the materials used for
construction. Concrete has the advantage of conserving space but is more costly
than synthetic or clay liners. The following cost comparisons for alternative
diking systems were presented by Hansen (1990). In each alternative, a 10
percent contingency was included in the total cost. Also security fencing at
$10 per linear foot was included in each alternative. A typical secondary
containment for six tanks, all 12 feet in diameter, the largest having a capacity
of 30,000 gallons, costs $26,000 if made of concrete. Per square foot of floor
area the concrete dike costs about $11.00.
A clay-lined-earthen-dike with the same floor area would cost $14,000. Due
to the sloping sides, the earthen dike can contain a tank with a volume up to
45,000 gallons. Per square foot of floor area the earthen dike costs about
$6.00.
A similar dike with a hypalon liner sandwiched between polypropylene liners
will cost $19,500, or $8.25 per square foot of floor area. The polypropylene
liners, geotextile liners, are needed to protect the main liner from damage
during installation. In some synthetic liner installations one or both
geotextile liners can be ommited if clean sand or smooth pebbles are adjacent to
the hypalon liner and steps are taken to protect the liner during installation.
This can result in a savings of 13 to 40 cents per square foot of floor area.
Dealers typically spread containment construction over a two- or three-year
period and regulations generally have a compliance schedule spanning a similar
time period. The areas and materials at dealerships requiring containment are
prioritized in most regulations and should be prioritized by dealers scheduling
containment work over an extended period. Containment work should be prioritized
in the following order; water system protection, pesticide storage containment,
loading/mixing/equipment washing area containment, and fertilizer storage
containment.
CONCLUSION
Before designing a complete containment system, dealers should visit sites
and study existing systems. Dealers with containment systems are a valuable
source of information, particularly if they have operated a system for some time.
Experience and hind-sight are invaluable. A good system design should
incorporate methods for expanding in the future. Provisions for the construction
of roofs over areas subject to incidental spills should be included in the long-
range plan.
Even in states where there are no containment regulations, dealers should
contact local agencies involved with water supplies, such as the Health
Department, Local Emergency Management Agency, and the local Environmental
Regulatory Agency when modifying a facility. For assistance in designing
containment, the Cooperative Extension Service, State Department of Agriculture,
fertilizer and ag-chemical dealer organizations and TVA's National Fertilizer and
Environmental Research Center can be contacted.
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Fertilizer and pesticide containment provides opportunities for the retail
fertilizer industry to take a leadership role in protecting our water resources.
Indications are that there will be more and not less regulation for fertilizer
and ag-chemical dealers in the future. It is everyone's responsibility to
protect our water resources. After all, we are only borrowing this water from
our descendants.
BIBLIOGRAPHY
Noyes, Ronald T., 1989. "Modular Concrete Wash/Containment Pad for Agricultural
Chemicals", Paper No. 891613, American Society of Agricultural Engineers, St.
Joseph, MI, December 1989.
Illinois Department of Agriculture, 1989. Part 255 Aqrichemical Facilities;
Subchapter i: Pesticide Control; Chapter I: Department of Agriculture; Title
8: Agriculture and Animals, 111 inois Department of Agriculture, Springfield, IL.
South Dakota Department of Agriculture, 1989. Bulk Commercial Fertilizer
Operations Manual. South Dakota Department of Agriculture, Division of Regulatory
Services, Pierre, SO, July, 1989.
Iowa Department of Agriculture, 1988. Bulk Commercial Fertilizer Storage. Article
12:44; Chapter 12:44:05, Iowa Department of Agriculture, Des Moines, IA.
Wisconsin Department of Agriculture, Trade & Consumer Protection, 1988. Chapter
Ag 162, Bulk Fertilizer Storage, Wisconsin Administrative Code, Register,
February, 1988, No. 386, Wisconsin Department of Agriculture, Madison, WI.
Minnesota Department of Agriculture, 1989. Bulk Pesticide Storage Facility Rule
Summary. Minnesota Department of Agriculture, Agronomy Services Division, St.
Paul, MN.
Kammel, D. W.; G. L. Riskowski, R. T. Noyes, V. L. Hofman., 1990. Draft of
Fertilizer and Pesticide Containment Facilities Handbook, Midwest Plan Service,
Agricultural Engineering, Iowa State University, Ames, IA.
Hansen, T. L., 1990. "Diking Alternatives for Secondary Containment of Liquid
Fertilizers". Dultmeier Engineering Services, Inc. Omaha, NE. January, 1990.
185
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HP a wo.o'
PLAN
CO
en
Liquid Holding Capacity in Gallons
LHC = 7.5 x L x W x 12
3
Where.
L — pad length in feat
W = pad width In feet
D = depth at sump inlet in feet
7.5 = gallons per cubic foot
LHC = 7.5 x 60 x 12 x 2.2
J
= 3960 gallons excluding sump
By adding a 4" high rollover curb around the pad
the LHC Is increased by 1800 gallons.
LHC of the curb is computed as follows:
LHC = 7.5 x L x W x CH
where.
CH = curb height in feet
LHC - 7.5 x 60 x 12 x O.3J
LHC = WOO gallons
Figure 1
LOAD PAD FOR SINGLE VEHICLE
-------
60
IP EL 9/9.5' -^
SLOP IT ^
„ SLOP£
H)
N
HP E.L 100.0'
PLAN
The Liquid Holding Capacity for this pad is
computed by the equation
IHC. =7.5 x L x W 4 Q
2
LHC = /,.? x 60 x 12 x 1.5
2
LHC — 4,050 gallons excluding the trough
Figure 2
SINGLE VEHICLE LOAD PAD WITH TROUGH
187
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CO
00
2'X 4' SUMP W/SAND TRAP
fr
r6
'
PLAN
4" SPLASH CURB
lrk=£J"
SECTION A-
*
, ..I'll.. *' J|'U
•-I \ -Hl~rfM- \
SUMP DETAIL
Figure J
LOAD PAD WITH SUMP
AND PERIMETER SAND TRAP
-------
00
to
rfl
SECTION A-A
SCALE: 1/4' = 1'-0
Figure 4
LOAD PAD WITH TWO SUMPS
-------
'4 REBAR @ 12'O.C. —^
CLEAN ie SCARIFY — ,
(-\iir~T /VW^P/~7T~ / 1
a
/-
-9*
tX/o / t-t/'VOj (L /C. / 1 /
SURFACE L_ \f
~^S
<- #4 ff£SA/? SET /A/ EPOXY
W' INTO EXIST CONCRETE
/- JOINT SEALANT
— ^
DRILL SLAB TO
RECEIVE DOWEL
Figure 5
NEW CURB ON EX/SUNG CONCRETE
6" COMPACTE.
SAND OR GRAVEL
Figure 6
CONTAINMENT
190
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#4 BARS S
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COMPACTED $>*
-------
01
4
T/WALL EL 100.0'
HP EL 97.42'
6"(TYP)
LP EL 96.58'
-,/- 2'X 2'X 2' SUMP
Iff W/SANDTRAP
o
-------
NEW BOTTOM
COMPACTED SAND
EXIST TANK WALL
•DRILL 1"0 WEEP HOLES
AROUND TANK
® ABOUT 5' O.C.
EXIST TANK BOTTOM
Figure 9
FALSE BOTTOM TANK
6" CRUSHED STONE
OR GRAVEL-} 20
W\
J'
12'
~6" CLAY / SOIL MIXTURE
COMPACTED EARTH
Figure 10
CLAY LINED EARTHEN DIKE
»US GOVERNMENT PRINTING OFFICE ] 9 92 -6 *• 8 - " 5 3/. o 6 3 1 193
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TECHNICAL REPORT DATA
(fleau read Instructions on the reverse before completinf)
REPORT NO.
:PA/600/9-91/047
3. RECIPIENT'S ACCESSION NO.
PB92-11994Q
TITLE AND SUBTITLE
Proceedings of International Workshop on Research in
'esticide Treatment/Disposal/Waste Minimization
6. REPORT DATE
January 1992
6. PERFORMING ORGANIZATION CODE
AUTHORIS)
VARIOUS
8. PERFORMING ORGANIZATION REPORT NO.
PERFORMING ORGANIZATION NAME AND ADDRESS
cience Applications International Corporation
635 W. 7th Street
Suite 403
Cincinnati, OH 45203
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-C8-0061
2. SPONSORING AGENCY NAME AND ADORE
U.S: EPA
RREL And
26 W. Martin Luther King Dr.
incinnati, OH 45268
^Tennessee Valley Authorit
NFE2J
P.O. Box 1010
Muscle Shoals, AL 35660
13. TYPE OF REPORT AND PERIOD COVERED
Proceedings
14. SPONSORING AGENCY CODE
EPA/600/14
5 SUPPLEMENTARY NOTES
Project Officer: T. David Ferguson Comml. (513) 569-7518
FTS 684-7518
6. ABSTRACT
The International Workshop on Research in Pesticide Management, Disposal, and
Waste Minimization was held in Cincinnati, Ohio, February 26-27, 1991. The purpose of
this workshop was to provide government officials, pesticide user groups, pesticide
producers and farm organizations practical solutions to pesticide treatment and disposal
problems. The workshop focused on how to destroy pesticides and their residuals at
low cost by the applicators and dealers. The technical program included presentations
by government researchers and regulators, university agricultural station professors,
industry experts and individuals involved in pesticide disposal and treatment.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATi Field/Croup
1) Pesticide
2) Herbicide
3) Insecticide
4) Fungicide
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (Tliis Report)
UNCLASSIFIED
21. NO. OF PAGES
208
20. SECURITY CLASS /This page I
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (R«». 4-77) PREVIOUS COITION is OBSOLETE
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