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Abstract

The U.S. Environmental Protection Agency (EPA) has funded

a pilot project to assist small and medium-size manufacturers

who want to minimize their generation of waste but who lack

the expertise to do so. In an effort to assist these manufacturers Waste Minimization Assessment Centers (WMACs) were

established at selected universities and procedures were

adapted from the EPA Waste Minimization Opportunity Assessment Manual (EPA/625/7-88/003, July 1988). That document has been superseded by the Facility Pollution Prevention

Guide (EPA/600/R-92/088, May 1992). The WMAC team at

Colorado State University performed an assessment at a plant

that manufactures intermediates for pharmaceuticals and other

chemicals. Raw materials and preprocessed materials undergo verification and blending and mixing. The resulting

advanced pharmaceutical intermediates are then shipped to

another plant for final processing. The team’s report, detailing

findings and recommendations, indicated that the waste streams

generated in the greatest quantities are waste solvents that are

reused onsite, incinerated as fuel in an onsite boiler, or shipped

offsite for disposal. The greatest cost savings could be achieved

by reusing additional amounts of methylene chloride in the

plant.

This Research Brief was developed by the principal investigators and EPA’s National Risk Management Research Laboratory, Cincinnati, OH, to announce key findings of an ongoing

research project that is fully documented in a separate report

of the same title available from University City Science Center.

Introduction

The amount of waste generated by industrial plants has become an increasingly costly problem for manufacturers and an

additional stress on the environment. One solution to the

problem of waste generation is to reduce or eliminate the

waste at its source.

University City Science Center (Philadelphia, PA) has begun a

pilot project to assist small and medium-size manufacturers

who want to minimize their generation of waste but who lack

the in-house expertise to do so. Under agreement with EPA’s

National Risk Management Research Laboratory, the Science

Center has established three WMACs. This assessment was

done by engineering faculty and students at Colorado State

University’s (Fort Collins) WMAC. The assessment teams

have considerable direct experience with process operations in

manufacturing plants and also have the knowledge and skills

needed to minimize waste generation.

The pollution prevention opportunity assessments are done for

small and medium-size manufacturers at no out-of-pocket cost

to the client. To qualify for the assessment, each client must

fall within Standard Industrial Classification Code 20-39, have

gross annual sales not exceeding $75 million, employ no more

than 500 persons, and lack in-house expertise in pollution

prevention.

The potential benefits of the pilot project include minimization

of the amount of waste generated by manufacturers, and

reduction of waste treatment and disposal costs for participating plants. In addition, the project provides valuable experience for graduate and undergraduate students who participate

in the program, and a cleaner environment without more regulations and higher costs for manufacturers.

Pollution Prevention Assessment for a

Manufacturer of Pharmaceuticals

ENVIRONMENTAL

RESEARCH BRIEF

Harry W. Edwards*, Michael F. Kostrzewa*,

and Gwen P. Looby**

* Colorado State University, Department of Mechanical Engineering

** University City Science Center, Philadelphia, PA

E AP

United States

Environmental Protection

Agency

National Risk Management

Research Laboratory

Cincinnati, OH 45268

Research and Development EPA/600/S-95/030 August 1995
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Methodology of Assessments

The pollution prevention opportunity assessments require several site visits to each client served. In general, the WMACs

follow the procedures outlined in the EPA Waste Minimization

Opportunity Assessment Manual (EPA/625/7-88/003, July 1988).

The WMAC staff locate the sources of waste in the plant and

identify the current disposal or treatment methods and their

associated costs. They then identify and analyze a variety of

ways to reduce or eliminate the waste. Specific measures to

achieve that goal are recommended and the essential supporting technological and economic information is developed. Finally, a confidential report that details the WMAC’s findings

and recommendations (including cost savings, implementation

costs, and payback times) is prepared for each client.

Plant Background

This plant manufactures intermediates for pharmaceuticals and

other miscellaneous chemicals. Over six million pounds of

product are produced annually during 8,640 hr/yr of operation.

Manufacturing Process

Production is performed by the plant in batches. The required

raw materials and pre-processed materials are received from a

sister plant. The production of the pharmaceuticals requires

several reaction and purifying steps that are combined to make

up a single batch. Batches isolate either intermediate or final

products. Several intermediates may be required to get to the

final product stage.

An abbreviated process flow diagram for the manufacture of

pharmaceuticals is shown in Figure 1.

Existing Waste Management Practices

This plant already has implemented the following techniques

and policies to manage and minimize its wastes.

• The Responsible Care program of the Chemical

Manufacturer’s Association is used as the plant’s waste

minimization vehicle. The program emphasizes pollution

prevention at the source rather than end-of-pipe solutions.

• An average of 95% of solvents are reused by the plant.

• Some of the spent solvents are incinerated onsite to produce

required steam, thereby reducing purchased fuel consumption.

• Off-specification batch materials are reused.

• Enclosed centrifuges are used for dedicated processes to

reduce air emissions of volatile organic compounds from

solvents.

• A policy has been implemented for the chemists to avoid new

production processes that require metallic compounds or

chlorinated solvents.

• A site reduction plan for air emissions that includes a mass

spectrometer used to monitor air emissions throughout the

plant has been implemented.

• Since the initial site visit by the WMAC assessment team,

some of the production steps for one of the products have

been revised thereby reducing the generation rate of waste

acetone dramatically.

Pollution Prevention Opportunities

The type of waste currently generated by the plant, the source

of the waste, the waste management method, the quantity of

the waste, and the waste management cost for each waste

stream identified are given in Table 1.

Table 2 shows the opportunities for pollution prevention that

the WMAC team recommended for the plant. The opportunity,

the type of waste, the possible waste reduction and associated

savings, and the implementation cost along with the simple

payback time are given in the table. The quantities of waste

currently generated by the plant and possible waste reduction

depend on the production level of the plant. All values should

be considered in that context.

It should be noted that the economic savings of the opportunity, in most cases, results from thereduction in raw material

and costs associated with waste treatment and disposal. Other

savings not quantifiable by this study include a wide variety of

possible future costs related to changing emissions standards,

liability, and employee health. It also should be noted that the

savings given for each opportunity reflect that pollution prevention opportunity alone and do not reflect duplication of savings

that may result when the opportunities are implemented in a

package.

Additional Recommendations

In addition to the opportunities recommended and analyzed by

the WMAC team, several other measures were considered.

These measures were not analyzed completely because of

insufficient data, minimal savings, implementation difficulty, or

a projected lengthy payback. Since these approaches to

pollution prevention may, however, increase in attractiveness

with changing conditions in the plant, they were brought to the

plant’s attention for future consideration.

• Reuse the water from the onsite wastewater treatment plant

as make-up water for the cooling tower.

• Install suitable storage tanks, piping, and a pump to permit

onsite reuse of waste hexane.

• Install a sludge dryer to remove water from the wastewater

treatment sludge.

• Extend the life of the solvents used for tank cleaning by

implementing staged cleaning.

• Install a small solvent recovery unit to distill small volumes of

waste solvent for reuse onsite.

This research brief summarizes a part of the work done under

Cooperative Agreement No. CR-819557 by the University City

Science Center under the sponsorship of the U. S. Environmental Protection Agency. The EPA Project Officer was Emma

Lou George.
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Figure 1. Abbreviated process flow diagram for pharmaceutical manufacture.

Primary Pharmaceutical

Intermediates

Blending

and

Mixing

Reuse

Off-spec

Products

Cleaning

Verification Waste

Solvents

Waste

Solvents

Waste

Solvents

Waste Filtercake

Shipped Offsite

By-products

Shipped Offsite

Reuse

Advanced

Pharmaceutical

Intermediates

Offsite Recycling

and/or

Incineration

Onsite

Incineration
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Table 1. Summary of Current Waste Generation

Annual Quantity Annual Waste

Waste Stream Generated Source of Waste Waste Management Method Generated (lb/yr) Management Cost

Waste solvents (acetone, toluene, methanol, Verification, blending and mixing, Reused onsite in subsequent 63,442,000 $ 01

THF, hexane, ethyl acetate, isopropyl ace- and clean-up formulations

tate, DMF, methylene chloride, acetic acid,

heptane, ethyl ether, dimethoxy methane)

Waste solvents (acetone, toluene, methanol, Verification, blending and mixing, Incinerated as fuel in onsite boiler 2,359,000 01

THF, hexane, ethyl acetate, isopropyl ace- and clean-up

tate, DMF, acetic acid, heptane, ethyl ether,

dimethoxy methane)

Waste solvents (acetone, toluene, methanol, Verification, blending and mixing, Shipped offsite to disposal facility for 2,333,500 329,0402

THF, hexane, ethyl acetate, isopropyl ace- and clean-up recycling and/or incineration

tate, DMF, methylene chloride, acetic acid,

heptane, ethyl ether, dimethoxy methane)

Waste process sludge Byproduct of production Shipped offsite for stabilization and burial 412,000 133,0002

Filter cake/solid wastes Blending and mixing of product Shipped offsite to disposal facility for 26,700 85,2002

recycling and/or incineration

Wastewater Various plant areas Treated in onsite wastewater treatment 395,000,000 81,1003

plant and sewered

Wastewater treatment sludge Onsite wastewater treatment plant Shipped offsite for burial 240,000 90,8002

1 No cost reported by plant 2 Waste disposal costs 3 Waste disposal cost and value of lost raw material
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Table 2. Summary of Recommended Waste Minimization Opportunities

Annual Waste Reduction

Net Annual Implementation Simple

Minimization Opportunity Waste Stream Reduced Quantity (lb/yr) Per Cent Savings Cost Payback (yrs)

Reuse the waste methylene chloride from Waste solvent shipped offsite 141,000 6 $70,200 $80,000 1.1

the last stage of each campaign for a par- (methylene chloride)

ticular product in subsequent campaigns.

Reuse a portion of the waste methanol gen- Waste solvent shipped offsite 153,410 7 46,900 40,000 0.9

erated as make-up in the low-temperature (methanol)

cooling system. Waste solvent incinerated onsite 222,590 9

(methanol)

Reuse the methanol used in the verification Waste solvent shipped offsite 27,380 1 8,370 24,000 2.9

process in the production and cleaning pro- (methanol)

cesses. Waste solvent incinerated onsite 39,720 2

(methanol)
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BULK RATE

POSTAGE & FEES PAID

EPA

PERMIT No. G-35

United States

Environmental Protection Agency

National Risk Management Research Laboratory (G-72)

Cincinnati, OH 45268

Official Business

Penalty for Private Use

$300

EPA/600/S-95/030