For the last 25 years, PowerPoint has served as the main presentation tool, replacing outdated technologies such as 35mm slides and overhead projectors. What did presenters utilize prior to 35mm slides? In this CWEA History column, we explore the “Magic Lantern” or “Stereopticon,” along with glass slides, which were instrumental in showcasing presentations and preserving a distinctive part of wastewater treatment history.
This story begins in 1913 when the cities of Pasadena, Alhambra, and South Pasadena- known as the Tri-Cities partners- jointly sought a solution to their increasing wastewater treatment and disposal issues. The Tri-Cities commissioned a board of engineers comprised of the three city engineers from the Tri-Cities partners to develop alternative solutions for a regional wastewater treatment plant. In 1914, following a comprehensive study, the board of engineers recommended the most viable option: purchasing 600 acres of ranch land (the Reppeto Ranch) south of the Tri-Cities area to construct an Imhoff tank and sprinkling filter treatment plant on the site. After gaining approval for the plan, the Tri-Cities partners applied for a state permit to build the treatment plant in early 1916. Unfortunately, the recommended alternative did not sit well with the residents near the ranch site.
The residents successfully blocked the plans by incorporating the City of Monterey Park, which included the 600-acre ranch land within the new city limits. The first action taken by the City of Monterey Park was to pass an ordinance prohibiting the construction of wastewater treatment facilities within its boundaries. As part of the opposition to the proposed treatment plant at Reppeto Ranch, residents of the Monterey Park area also submitted an affidavit to the Los Angeles County Board of Supervisors, claiming that odors from a modern sewage treatment plant “were known to kill” within a range of “4 miles” from the facility. This information regarding the “toxicity” of odors was reported to relate to the operation of a treatment plant in Atlanta, Georgia, which employed an Imhoff tank/sprinkling filter treatment process similar to that of the Tri-City Board of Engineers proposal.[i]
In 1916, partly to counter the allegations of toxic odors, T.D. Allin, the Commissioner of Public Works in Pasadena, and R.V. Orbison, Pasadena’s City Engineer, embarked on a seven-week train trip across the United States to inspect major municipal sewage treatment plants and review the latest sewage treatment technologies. The municipal treatment plants they visited included those serving the cities of Chicago, Boston, Houston, Atlanta, Baltimore, Philadelphia, Cleveland, Rochester, Milwaukee, and several others. Allin and Orbison’s findings debunked the “toxic odors” allegations, but more significantly, the activated sludge facilities they visited impressed them with the process’s flexibility and treatment efficiency compared to Imhoff tanks and sprinkling filters – they found it “was getting better results than any other process known.” It was this favorable impression of the activated sludge process that influenced the next steps in finding a solution to the Tri-City partners’ sewage treatment and disposal problem.
Allin and Orbison were impressed by the newly activated sludge treatment plants they visited, as these facilities were relatively odor-free and had a comparatively compact footprint. By utilizing the activated sludge process, the City of Pasadena’s existing 320-acre sewer farm could still serve as a site for wastewater treatment, even with residential development on its boundaries. This provided a solution to the Tri-City partners’ need for a new treatment plant site and allowed for effluent discharge into the nearby Rio Hondo River.
As part of their public outreach efforts, Allin and Orbison photographed the wastewater treatment plants they visited and converted the photos into glass slides that could be projected using a Magic Lantern, or more accurately, a stereopticon, as illustrated by Figure 1. With the stereopticon and glass slides, Allin and Orbison developed a public outreach slide show and embarked on a series of presentations to community groups, eventually presenting their slide show to the League of Pacific Municipalities at its annual convention in 1917.
Figure 1. A Stereopticon Projector Similar to the Projector used for the 1917 Wastewater Treatment Slide Shows
Allin and Orbison’s mission was to use their presentation to demonstrate that wastewater treatment plants did not generate toxic odors, show that the activated sludge process was the preferred alternative as it allowed for the continued use of the City of Pasadena’s existing sewer farm site, illustrate how pilot testing treatment processes at the City of Pasadena site confirmed the benefits of using the activated sludge process, gain support to finance the construction of a new wastewater treatment plant at the City of Pasadena site, and highlight the potential to sell treated sludge (biosolids).
The presentations were successful. The activated sludge process was evaluated and selected; the plant was funded, and by 1924, the new Tri-Cities treatment plant was operational, processing wastewater from the Cities of Pasadena, Alhambra, and South Pasadena. The glass slides were placed in storage and were forgotten until later when they were donated to the Pasadena Public Library.
In 2013, I began researching the history of the City of Pasadena’s “Sewer Farm” (circa 1890) as part of the CWEA’s History Committee’s effort to document California’s early wastewater treatment facilities. In my search for photographs of the Pasadena Sewer Farm, I contacted the Pasadena Public Library, which provided me with photographs of the Sewer Farm taken in 1903.
Dan McLaughlin, the reference librarian, informed me that the library had impressive glass slides of the City Farm from 1915, part of a larger presentation from the city’s street department that he would happily show me. If they were indeed from the City Farm, he could scan them for me.
I replied that I was most definitely interested in seeing the slides as they would have been when the concept of a new Tri-City wastewater treatment plant was being developed. McLaughlin then put me in contact with Ketzie Diaz, who was assigned the project of identifying the images on the glass slides.
Diaz later reached out to me, hoping I could assist with the origin of some glass slides the library possessed that seemed to depict various processes of the city’s Sewer Farm. Some of the images don’t seem to be directly related to the Farm, appearing more like street maintenance and repair
When I received copies of the slides, I could identify the wastewater treatment processes in about 90% of them. Interestingly, the majority of the slides related did not appear to be photographs of Pasadena’s farm. Instead, they seemed to be photographs taken by the board of engineers of treatment plant processes in other cities, like the ones commissioned for review by the Tri-Cities partners. The glass slides were fascinating to me as they showed the construction of Imhoff tanks.
After reviewing the glass slides, I realized that the photos were the same photos used in a 1917 article by Allin and Orbison published in the periodical Pacific Municipalities entitled How Other Cities in the United States are Disposing of Their Sewage. Eureka! The Pacific Municipalities article turned out to be the key to identifying the photos. Thanks to Allin and Orbison’s descriptions and reprints of the photos in the article, I was able to send Diaz the detailed descriptions of the photos.
I should note that I was also able to identify the work documented by the Pasadena Street maintenance glass slides that were stored with the wastewater treatment plant slides. I found that T.D. Allin also used these glass slides for a conference presentation.
Figures 2 through 7 show a sample of the glass slide collection for your viewing.
The Pasadena Public Library’s glass slide collection features 33 slides of various wastewater treatment plants from across the United States. Some slides depict treatment plants under construction, while others showcase operational facilities. These slides are significant as they capture a moment in time when wastewater treatment technology in the U.S. was experiencing rapid changes.
Most significant is the fact that the slides document the very early adoption of the activated sludge process in the U.S. Considering that the activated sludge process was discovered in England in 1914, it is truly amazing how quickly the process was adopted in the U.S., especially given the state of communications at the time with no internet. In just two years time, the activated sludge process was being tested in California for designing a treatment plant, and a fully operational activated sludge plant was online in the U.S. (1916, San Marcos, Texas). These facts and the glass slides have inspired ongoing research into the early mechanisms for the rapid transfer of technical information and the adoption of the activated sludge process in the U.S. during the first half of the 20th century.
It’s also worth noting that William Allen, CWEA President (1931-32), served as the Superintendent of the new Tri-Cities treatment plant for many years before becoming the Deputy City Manager of Pasadena.
Figure 8. Worker Shoveling Dried Sludge at the Pasadena Sewer Farm.
Finally, Figure 8 displays a real California “sludge shoveler” at work in Pasadena, well before the advent of the “5-S. ”
[i] Orbison, R.V. and Allin, T.D., How other Cities in the United States are Disposing of Their Sewage (San Francisco, Pacific Municipalities, 1917) 62.
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