An Analysis of Pollution Prevention Opportunities and Impediments in the Chemical and Allied Products Sector in Georgia — Part 2

Sector Profile

Background

According to the Georgia Manufacturing Directory, there were 468 firms listed within the chemical and allied products sector in 1994. These firms operate 502 facilities in Georgia and employ 20,461 workers. The average weekly wage was $711 in 1994, which was the second highest of all the manufacturing sectors and well above the average manufacturing wage in Georgia of $517 per week. The sector is made up of primarily small facilities. Approximately 80% of the facilities have less than 50 employees, and half have less than 20 employees as illustrated in Figure 1.

Figure 1: Facilities Categorized by Size

The facilities within the sector are engaged in manufacturing a broad array of products. Because of this, there is a wide variety of materials, manufacturing processes, and wastes within the sector. The SIC code has been used to group the facilities in this analysis. Table 1 shows the distribution of facilities in the sector according to their primary product. The table also shows the number of facilities by SIC code who are TRI and biennial reporters. About 40% of the facilities report on the TRI, and about 15% are large quantity generators of hazardous waste.

Table 1: Chemical Sector Facilities According to Standard Industrial Classification

Standard Industrial Classification

Manufacturing Directory

1994 TRI Reporters

1993 Biennial Reporters

2812 Alkalies & Chlorine

2

4

2

2813 Industrial Gases

19

5

0

2816 Inorganic Pigments

8

3

1

2819 Industrial Inorganic Chemicals

51

17

4

2821 Plastic Materials & Synthetic Resins

20

26

8

2822 Synthetic Rubber

3

0

0

2824 Cellulosic Manmade Fibers

3

1

1

2833 Medicinal Chemicals

3

2

2

2834 Pharmaceutical Preparations

9

1

2

2835 In Vitro & In Vivo Diagnostic Substances

9

0

0

2836 Biological Products

6

0

0

2841 Soap & Other Detergents

30

13

3

2842 Specialty Cleaning Preparations

41

16

3

2843 Surface Active Agents & Finishing Agents

18

9

0

2844 Perfumes, Cosmetics, & Other Toilet Preparations

13

2

0

2851 Paints, Varnishes, Lacquers, & Enamels

54

14

16

2861 Gum & Wood Chemicals

2

1

0

2865 Cyclic Organic Crudes, Organic Dyes & Pigments

10

1

0

2869 Industrial Organic Chemicals

18

10

9

2873 Nitrogenous Fertilizers

16

2

0

2874 Phosphatic Fertilizers

6

2

0

2875 Fertilizers, Mixing Only

45

1

0

2879 Pesticides & Agricultural Chemicals

16

10

3

2891 Adhesives & Sealants

35

13

3

2892 Explosives

0

1

0

2893 Printing Ink

21

6

6

2895 Carbon Black

0

0

0

2899 Chemicals, Not Elsewhere Classified

44

22

3

Total

502

182

66

To gain a better understanding of the manufacturing processes in the sector, 147 facilities were contacted; resulting in 68 completed surveys. Of the respondents, approximately half were TRI reporters and half were not. A typical operation could be described as a small facility engaged in formulating products via a batch processing operation. The sector survey indicated that batch processes out number continuous processes by a five to one margin. Most of the manufacturing processes were engaged in the formulation of raw material components into a product. Only one-third of the facilities reported using chemical reactions or other more sophisticated chemical processing beyond formulation or repackaging. Half of the facilities surveyed reported aqueous equipment cleaning, and one-third reported using solvents for equipment cleaning. Survey responses to process activities are listed in Table 2.

Table 2: Survey Responses by Types of Process Activities

Process Activity

All Respondents

TRI Reporters

Non-TRI Reporters

Batch Processing

79%

78%

81%

Continuous Processing

16%

27%

3%

Repackaging

25%

19%

32%

Reformulation

85%

78%

94%

Reacting, Distilling, Etc.

35%

51%

16%

Aqueous Equipment Cleaning

50%

57%

42%

Solvent Equipment Cleaning

32%

30%

35%

Heating of Process Materials

40%

51%

26%

Chilling of Process Materials

21%

24%

16%

Waste Treatment

28%

38%

16%


Waste Generation

In 1994, over 20 million pounds of waste TRI chemicals were generated within SIC 2800. Since 1991, there has been a 33 percent decrease in the amount of waste chemicals generated. Figure 2 shows the trend of TRI chemicals generated as wastes from 1991 to 1994.

Figure 2: Total TRI Chemicals Generated in SIC 2800

Of the waste chemicals generated in 1994, 40 percent were listed as transfers, 42.5 percent were air emissions, 15 percent as releases to water, and 2.5 percent as releases to land. Of the releases to the environment, air remains the most significant media. Figure 3 shows releases by media from 1991 to 1994. Air includes releases report as stack emissions and as fugitive releases. Water includes direct discharges and releases to a Publicly Owned Treatment Work (POTW).

Figure 3: Air, Water, and Land TRI Releases

In 1994, the top chemical wastes released by quantity to air were ammonia (42%), methyl isobutyl ketone (13%), toluene (6%), xylene (5%), dichloromethane (4%), and methanol (4%). The largest contributors to air releases by SIC code were 2819 (23%), 2873 (22%), 2861 (16%), and 2869 (14%).

The vast majority of water releases were reported as ammonium nitrate (68%), methanol (18%), and ammonia (9%). By industry, SIC 2873 (49%), 2819 (25%), and 2869 (20%) were the primary contributors. Chromium (84%) and nickel (9%) accounted for the majority of land releases, and SIC 2819 was the most significant industry contributor of land releases.

While there is a wide variety of chemicals reported under the TRI, this analysis will focus on those that are released in large quantities and that are frequently used by the facilities in the sector. The top TRI chemicals are listed by frequency in Table 3 and by quantity in Table 4.

Table 3: Most Frequently Reported TRI Chemicals for SIC 28

Chemical

# of Reportings

Chemical

# of Reportings

Glycol Ethers

60

Formaldehyde

14

Sulfuric Acid

60

Copper / Copper Compounds

13

Ammonia

43

1,2,4-Trimethylbenzene

12

Methanol

40

Chlorine

12

Phosphoric Acid

40

Ethyl Benzene

12

Toluene

38

Nitric Acid

12

Xylene

36

Barium/ Barium Compounds

11

Hydrochloric Acid

34

Maleic Anhydride

11

Ethylene Glycol

31

Ammonium Nitrate

10

Zinc / Zinc Compounds

27

Chromium / Compounds

10

Dichloromethane

24

N-Butyl Alcohol

9

1,1,1-Trichloroethane

22

Acrylic Acid

8

Acetone

21

Magnesium / Compounds

8

Methyl Ethyl Ketone

17

Methyl Isobutyl Ketone

8

Styrene

15

Tetrachloroethylene

8

Table 4: TRI Chemicals Reported in SIC 2800 by Quantity (pounds)

Chemical

Quantity

Chemical

Quantity

Ammonia

3,773,230

Carbonyl Sulfide

250,000

Methanol

2,418,248

Glycol Ethers

221,942

Ammonium Nitrate

2,028,768

1,3 – Butadiene

221,498

Xylene

1,940,084

Chloroethane

210,500

Toluene

1,259,338

1,1,1 – Trichloroethane

198,005

Methyl Isobutyl Ketone

1,241,728

Vinyl Acetate

190,074

Styrene

990,054

Vinylidene Chloride

170,440

Dichloromethane

697,128

Sulfuric Acid

168,974

Methyl Ethyl Ketone

665,078

Hydrochloric Acid

110,434

Chromium / Chrom.Compounds

419,990

1,2,4 – Trimethylbenzene

105,106

Cyclohexane

354,779

Benzoyl Peroxide

98,419

Freon 142B

337,560

n – Hexane

92,416

Ethylbenzene

327,365

Freon 141B

92,397

Chlorobenzene

308,830

Nickel / Nickel Compounds

92,095

Benzene

275,827

Zinc / Zinc Compounds

69,749

According to TRI data, the majority of the chemicals generated as waste are used as raw materials in the manufacturing processes. These chemicals are used as formulation components of the final product 63 % of the time they were reported. 27% of the waste chemicals were used as reactants. The third most frequently reported use was for equipment cleaning at 13%. Other reported uses of generated chemicals were processing aids (9%), repackaging components (7%), and by-products (4%).

Common Source Reduction Techniques

Because of the very diverse nature of the sector, source reduction has been evaluated for each individual sub-sector. Some common source reduction techniques which can be applied to several of the processes found within the chemicals sector will be discussed here in general detail. Review of information found in biennial reports, TRI reports, and the survey indicated widespread use of source reduction techniques such as spill prevention, in-process recycling, and inventory control.

Facilities which use batch processing operations have in common source reduction techniques such as production scheduling, alternative cleaning methods, and rinsate reuse. Receipt and shipment of chemicals in small quantities is another area common to several sub-sectors. The sector survey indicated that nearly all the facilities reported some type of waste minimization activity. The most commonly reported activities according to the P2AD survey are listed in Table 5.

Table 5: Survey Responses by Waste Minimization Activity

Waste Minimization Method

All Respondents

TRI Reporters

Non-TRI Reporters

Spill & Leak Prevention

62%

62%

61%

External Recycling Markets

62%

68%

55%

In-process Recycling

60%

62%

58%

Process Optimization

46%

51%

39%

Inventory Control

44%

43%

45%

Raw Material Substitution

32%

30%

35%

Process Equipment Changes

31%

32%

29%

Alternative Packaging

29%

24%

35%

Alternative Product Design

26%

27%

26%

Energy Conservation

21%

19%

23%

Spill and Leak Prevention

Spill and leak prevention is first and foremost among pollution prevention techniques in the sector. The emphasis on spill and leak prevention has been widespread for more than a decade as a result of early safety and environmental regulations. Most facilities within the sector are required to have a Spill Prevention, Control, and Countermeasures (SPCC) plan.

Spill and leak prevention focuses on the storage, processing, and transfer of materials. Regular inspection and maintenance of piping, valves, pumps, process vessels, storage tanks, and containers effectively limit material losses. Leaks can be reduced by minimizing pipe fittings and flanges. Sealless pumps also reduce the possibility of leaks.

Spill and leak prevention is also applicable to non-hazardous materials frequently found in chemical plants such as cooling water, steam, condensate, heating oil, compressed air, and lubricants. Heat transfer, steam supply, and compressed air systems are typically included in preventive maintenance programs.

Inventory Control

A frequent source of waste is expired or contaminated raw materials. Many materials have a limited shelf life after which they cannot be used to make good product. Raw materials are often lost when contaminated or improperly stored. Coordinating the purchasing and consumption of raw materials will help eliminate material spoilage. Good housekeeping, material handling procedures, and container selection can significantly reduce waste from contamination and container damage.

Process Optimization / Quality Control

Process optimization reduces waste through higher yields. Many facilities reduce waste indirectly through their optimization and quality control efforts. Statistical process control is frequently used to optimize process through the identification of special causes which can then be targeted for improvement. Process optimization can be achieved with the use of automated process control devices. Reviewing operating procedures and employee training can also increase yields.

Quality control also applies to the purchase of raw materials. The processing of poor quality feedstocks results in higher waste generation as a result of producing off-spec products. Effectively screening in-coming materials to insure quality has the benefit of higher yields, more efficient processing, less off-spec products, and less waste.

Production Scheduling

For the batch processing of chemicals, production scheduling can be used as a means to reduce cleaning. Optimization of production scheduling can reduce the number of times it is necessary to clean equipment, and in doing so increase plant productivity. This can be accomplished by scheduling the production of the same or similar products in succession so that cleaning the tanks between batches is not necessary. Other product characteristics besides raw material compatibility which must be considered include order frequency, order size, cycle time, and shelf life.

The first step is to group the products into families based on raw material compatibility. A sequence of batches can then be formulated which do not require the tank to be cleaned between each batch. After determining product families, the next step is to maximize the dedication of equipment. Dedicating a particular tank to a specific family will further reduce cleaning requirements and the possibility of operator error during formulation. To determine which product families to dedicate to each tank, consider the order frequency of each product, the typical batch size and cycle time, and the shelf life of each product. This decision process is presented in a flow diagram in Figure 4.

Figure 4: Decision Process for Production Scheduling Optimization

The determination of production families must accommodate customer specifications. Identify the ingredients which distinguish the products from one another. Separate products whose ingredients are so incompatible that residuals remaining from a completed batch of one would adversely affect the integrity of the subsequent batch of the other product. Some lab analysis may be necessary to ensure product quality.

After establishing the product families, examine information on product demand. Optimizing batch sequencing necessitates some degree of flexibility in scheduling. Larger inventories and more accurate forecasting of demand may be necessary. Dedicating a tank to a product family will have the most impact on reducing cleaning. If the tank is not contaminated by an incompatible product, the need for frequent and thorough cleaning will be greatly reduced. Because of the number of parameters to consider, optimization of capacity utilization would be best accomplished by use of simulation software.

The benefits extend beyond waste minimization. The time spent cleaning equipment is essentially down time. Reducing the number of equipment cleanings allows more time for production and could increase the plant’s capacity. This is likely to result in a decrease in operating costs per unit of output. Additionally, dedicating tanks would simplify the operator’s job, thereby reducing the possibility of error in a batch formulation. An analysis of the current product mix would be needed to quantify the benefits of batch sequencing.

Undertaking this type of endeavor will require the dedication of personnel time to assimilate and analyze the production information. Changing production scheduling will have an impact on product storage and inventory management. Additional storage space may be required. Investment in a computerized, production scheduling system may also be essential.

In-Process Recycling

In-process recycling is the direct reuse of waste materials in the process to make the originally intended product. This method is particularly effective in processes where quality constraints are not too demanding. In batch processes, equipment cleaning is a significant cause of waste generation, since a solvent or aqueous rinsate is used. Frequently, the rinsate can be collected and used in making a future batch of the same product.

Another opportunity for in-process recycling is through the containment and collection of spills, leaks, or other fugitive emissions. If the material is collected without being contaminated, it may be reintroduced to the process. A technique used to minimize the effect of slightly contaminated materials in the process is to mix a small amount of the material in question with a much larger amount of the virgin raw materials.

Dry Cleaning Methods

Equipment and floor cleaning is most often done using solvents or water with detergents which generate waste rinsate and wastewater. Sweeping floors instead of washing them down can reduce the contaminate levels in the wastewater. The use of squeegees or air knives can help to alleviate some of the problems associated with equipment cleaning. Specifically, it will help lower the concentration of residues in the rinsate. This may be crucial to the viability of washing alternatives which decrease water usage, and thereby carry a higher concentration of residuals.

Air knives could also be used to pre-clean equipment before a final washing. The air knife can be used to blow residue down the sides of tanks. Then, residues which have collected in the tanks or other apparatus can be pumped out or drained. Additionally, air blowing lines will help remove residues left in the piping. Neither method requires a significant investment, yet each would greatly enhance any effort to reduce wastewater.

Alternative Packaging

Packaging is usually the major cause of solid wastes, and can impact the efficiency of material handling and storage. Raw materials are commonly received in containers such as paper bags, drums, and tote bins. Bags typically have some type of moisture liner which precludes them from being recycled.

Drums, which may be made from metal, plastic, or fiber, also pose problems. While these materials can be recycled, residues remaining in the drums have to be removed, particularly if they are hazardous. Thus, rinsing the drums may enable them to be recycled, but wastewater is generated in the process. Drums with plastic liners are easier to reuse or recycle, and the amount of solid waste is reduced to the liner.

Receiving materials in reusable tote bins can minimize some of the problems associated with drums and bags. However, totes will still require some cleaning. Bulk transfer of materials via tanker truck is probably most efficient from a waste standpoint, as long as enough volume is consumed to justify it.

Recycling

A variety of wastes are addressed through recycling. Solvent recovery is probably the most common example in the sector. Solvents are recovered via solvent distillation units and then reused. In some instances, the solvent is not pure enough to use for its original purpose, so it is sold to an external market. As with other manufacturing sectors, there is a significant amount of solid wastes which are being addressed by recycling. Cardboard, plastics, pallets, paper, metals, and other packaging materials are recycled.

 

Impediments

Product quality and economic reasons were the most commonly reported barriers to pollution prevention in the P2AD survey. There were only small differences in comparing the responses of TRI reporters and non-reporters. Surprisingly, the facility size had little to do with the type of barriers cited.

Product quality is a concern when attempting in-process recycling, material substitution, and alternative packing. Economic reasons include increased operating costs and unavailability of capital funds. The use of full cost accounting can help justify some source reduction projects that would otherwise be overlooked.

In case studies and assessments, production scheduling was frequently considered when attempting to reduce waste, but having to schedule production in response to customer orders made it difficult. To optimize scheduling to minimize waste requires long production runs of the same or similar products, whereas optimizing scheduling to meet consumer demand requires short production runs of a variety of products, often with little advance notice.

Table 6: Survey Responses by Barrier to Waste Minimization

Barriers to Waste Minimization

All Respondents

TRI Reporters

Non-TRI Reporters

Product Integrity / Quality

24%

19%

29%

Not Economically Feasible

21%

16%

26%

Insufficient Capital

21%

24%

16%

Technology Limitations

18%

16%

19%

Limited In-house Expertise

13%

14%

13%

Regulations

7%

8%

6%

The P2AD survey, as listed in Table 7, showed that in general the facilities in this sector did not receive a lot of external assistance. This was particularly true of the non-TRI reporters who received most of their assistance from corporate personnel and vendors. TRI reporters appear to be more comfortable in requesting assistance from government and university programs.

Table 7: Survey Responses by Sources of Waste Minimization Assistance

Source of Assistance

All Respondents

TRI Reporters

Non-TRI Reporters

Corporate / Plant Management

31%

22%

42%

Vendors

18%

14%

23%

University Programs

18%

22%

13%

Consultants

15%

16%

13%

Government

12%

16%

6%

Industry / Trade Associations

4%

5%

3%

The size of the facility was also related to the amount of assistance received. Generally, the small facilities were dependent upon corporate management and vendors, whereas larger facilities reported all categories of assistance.

Table 8: Relationship Between Size and Assistance

Source of Assistance

More than 60 Employees

12 to 60 Employees

Less than 12 Employees

Percent Receiving Assistance

40%

45%

14%

Government, University, or Consultants

22%

13%

3%

Use of Recycling Markets

75%

48%

40%