February 2001

Glancing Back: Changes in Technology Over the Last 30 Years

By Lothar Lehmann
SRC Companies, Inc.

In the late 1950s, the first concept of a continuous rendering cooker was developed at the Baker Commodities plant in Los Angeles, CA, and the first production continuous cooker was installed at the Denver Rendering Company. This was the birth of the Dupps Company’s continuous cooker. By the early 1970s, a number of large rendering companies had converted from batch cookers to continuous rendering systems.

During the early 1970s, the most common continuous rendering systems were the Dupps and the Anderson IBEC evaporator systems. By the late 1970s, the Stord-Bartz system was introduced to the North American market, which included the disc drier/cooker and the low energy rendering systems. Stord-Bartz is known today as Atlas-Stord.

It was in the early 1970s when the Environmental Protection Agency (EPA) took a look at the industry, ultimately deciding they didn’t want anything to do with rendering. The task of regulating the air emissions of the industry was turned over to the states, and it was later decided to leave the rules and enforcement to the local agencies.

During the 1960s, very few rendering plants other than in Los Angeles County had any odor abatement equipment. In the early 1970s, a few rendering plants started to install air scrubbers and designated fume incinerators and the EPA and the states started mandating wastewater discharge regulations. Many small rendering plants had to close because they could not afford the large investment required for air and effluent abatement.

Renderers were confronted with a new government agency in the mid-1970s, the Occupational Safety and Health Administration (OSHA). Worker’s heath and safety became a major concern for renderers. During the early 1980s, Salmonella became a major challenge for the industry, at which time the Animal Protein Producers Industry’s Salmonella testing program was initiated and is still very active today. The program was the beginning of a general concern for food safety.

During the 1980s, there was a change in the way restaurant grease was collected. The old 55-gallon drum containers were changed to larger stationary grease containers. The grease is now pumped from this container or the container is picked up by a hydraulic unit and dumped into the bulk truck. Safety was a major reason for eliminating the handling of the 55-gallon drums.

Energy costs began to rise drastically in the early 1980s, emphasizing the need for more energy efficient processing equipment. The waste heat evaporator and the low horsepower raw material grinders are examples of new products that were developed.

In the mid-1980s, new rendering plants were built with more advanced process controls. More monitoring sensors were being utilized and the entire process was computer controlled. The result was a better-finished product quality, manpower savings, reduction in energy costs, and the availability of process data.

The continuous feather or hair hydrolizer and the bio-filter were introduced to the North American industry in the late 1980s. The bio-filter added another odor abatement technology for the industry. Many renderers started burning the high intensity odors in their steam boilers because of high fuel costs and more stringent odor emissions. Other renderers installed waste heat boilers in order to burn high intensity odors.

Starting in the early 1980s, as the consumption of meat shifted from red meat to poultry, more new rendering plants were constructed in the Southeast United States. Case ready meat and the trend of more packer renderers further reduced the availability of raw material for the independent renderer.

The 1990s brought many more challenges for North American renderers. Perhaps the greatest of these was the breakout of bovine spongiform encephalopathy in the United Kingdom. The first confirmed case was in 1986 and because of this, the rendering industry changed from the invisible industry to an industry that is now very visible. The 1990s also brought a real awareness for food safety and biosecurity.

Over the last 30 years, there have been many process innovations in the rendering industry. Some have been very successful and some did not succeed at all. Microwave cooking was an idea that did not prove to be a success.

Today’s rendering plants are larger, better maintained, more environmentally friendly, more energy efficient, and better managed. Almost all rendering plants now have continuous systems, with only a few batch cooker plants left in North America.

The next 30 years will bring more new process innovations. There will also be more government regulations. Many of these regulations will deal with food safety and biosecurity. Hazard Analysis and Critical Control Point (HACCP) will not go away. Every rendering plant will have to put a HACCP plan into effect. If they fail to do this on their own, the government will mandate that they do so.

With the recent drastic increase in energy costs, the need for energy efficient rendering systems will become a necessity. As a result of these extremely high energy costs, renderers have taken recycling to a new level by burning part of their finished product in the boilers. The problem of sludge will continue and new methods for processing sludge will be required.

Renderers have been very resilient in the past and will need to continue on this path in the future.