Originally, the humorous noun garbologist was chiefly used to designate a person whose job is to collect domestic refuse.

This noun is from garb- in garbage, and the combining form -ologist, denoting a person who is concerned with a particular subject or science.

—Cf. also:
– the noun garbology, which, originally, was chiefly used to designate the collection of domestic refuse;
– ‘garbageology’ | ‘garbageologist’: original meanings and early occurrences.

The earliest occurrences of the noun garbologist that I have found are as follows, in chronological order:

1-: From The Word Harvest of ’45, by Allen Walker Read, published in The Saturday Review of Literature (New York City, New York, USA) of Saturday 29^th June 1946—here, the garbologist is defined as an expert in the treatment of refuse:

For -itis we have crutchitis, electionitis, and queueitis. The ologies are also represented: “contrology” is a system of physical culture, “lipology” is the science of telling fortunes by lips, both “occupationology” and “jobology” serve interviewers of employment services, and “bagology” reveals the significance of the articles that women carry in their handbags. It turns out that the “garbologist” know [sic] the latest techniques in treating garbage.

2-: From 50-50: Letterettes in Fifty Words, published in the Daily Telegraph (Sydney, New South Wales, Australia) of Monday 21^st December 1953:

To householders who complain about garbage services I offer a challenge. How many of you would be willing to do the job and get some of the big money collectors are supposed to get? Do you think you would last a week? Collectors get an award wage and earn extra money by extra work.—“Garbologist.”

3-: From a letter by one Mrs. McAllister, from Seattle, published in the Victoria Daily Times (Victoria, British Columbia, Canada) of Saturday 3^rd July 1954:

As a visitor to your city I was very disappointed in not finding those pretty hanging baskets and the clean streets that have always been Victoria’s big attraction. It was certainly a let-down to the tourists who have always come from far away, to see Victoria, because of its clean, green parks, etc. Instead they found dirty streets, filled up waste baskets, with paper and such, on the main streets. As I went along asking why such a mess, I found out that the outside workers and garbologists are on strike.

4-: From the Evening News (Portsmouth, Hampshire, England) of Friday 28^th February 1958:

THE GARBOLOGIST

Following the lead of a ratcatcher who advertised as a “vermin controller and eradicator,” a Khandallah (Wellington) garbage collector now calls himself “a garbologist.”

5-: From the column The Town Around Us, published in The Ladysmith Chronicle (Ladysmith, British Columbia, Canada) of Thursday 31^st August 1961:

Village “garbologists” are having their troubles with the wasp menace this year. They could not dump some garbage cans at some homes because of the pests swarming around foodstuffs put in by residents. Municipal Clerk R. S. Wood suggested that, “Food waste should be buried in the garden where it will do the most good and garbage cans cleaned out periodically with disinfectant.” One “garbologist” told of a local resident who put fish remains in his garbage container and then meekly warned, “Watch out for the wasps.”

6-: From the following story by United Press International, published in many U.S. and Canadian newspapers in October 1965—for example in the Fort Lauderdale News and Sun-Sentinel (Fort Lauderdale, Florida, USA) of Saturday the 9^th:

HARTFORD, Conn. (UPI)—The McCauley Rubbish Removal Co. said Friday it would continue its newspaper campaign to have its men referred to as “your friendly garbologists.”
Raymond Esposito, a partner in the firm, said that in the current era of specialization it is only natural his men be known by the term. “They are certified garbologists,” he said.
He said that when his nine drivers make their collections, they wear red berets. “Otherwise, they wouldn’t stand out so much,” he said.

7-: From the column People in the News, published in the Philadelphia Daily News (Philadelphia, Pennsylvania, USA) of Wednesday 13^th October 1965:

DOCTORS OF DISPOSAL?

—The McCauley Rubbish Removal Co., Hartford, Conn., is conducting a public campaign to have its employes referred to as “your friendly garbologists.” The highfalutin rubbish collectors also are rigged out in bright red berets by order of Garbologist-in-Chief Edmund McCauley.

8-: From the column Friday Frivolities, by Ollie M. James, published in The Cincinnati Enquirer (Cincinnati, Ohio, USA) of Friday 15^th October 1965:

DID WE hear somewhere that there was a move on to call garbage men garbologists? Ruth Brown of our peerless classified advertising department saw a very elegant sign on the Rainbow Car Wash in Oakley:
COLLECTOR OF EXTERNAL RESIDUE
The guy going by with the big grin on his face is probably the Collector of Internal Revenue.

9-: From the column Our Slant, by Ed Minteer, published in the Albuquerque Journal (Albuquerque, New Mexico, USA) of Sunday 24^th October 1965:

A concern in Hartford, Conn., that removes rubbish refers to its employes as “garbologists”. The collectors wear red berets. If “garbologists” wearing red berets can get the job done better than just mere pick-up men, we’re all for giving the employes a distinguished title.

10-: From an editorial published in the Orlando Evening Star (Orlando, Florida, USA) of Friday 29^th October 1965:

‘Your Friendly Garbologist’

THE PLAN of a rubbish removal company in Hartford, Conn. to have its employes wear red berets and be referred to as “your friendly garbologist” follows the modern trend of upgrading the professions which render a service to mankind.
We can remember when any man who practiced medicine was invariably referred to as “Doc,” and a great guy he was too, but nowadays he is a general practitioner, unless he is a surgeon, a medical internist, a gynecologist, or orthopedist, a dermatologist, an obstetrician, a urologist, or an ophthamologist [sic].
WE DON’T know anyone who renders any greater service to suffering humanity than a garbage collector. Those who do not agree with us have only to live through a period in which local garbage collection procedures have broken down for a few days to change their minds.
It is not difficult work, but it is disagreeable and it doesn’t pay very well. We should be grateful to those who are willing to do it. If red berets, a significant title and a pat on the back will add to their esprit de corps and give them a sense of dignity as human beings, we’re all for it.

This cartoon illustrated ‘Your Friendly Garbologist’, published in the Orlando Evening Star (Orlando, Florida, USA) of Friday 29^th October 1965:

I GOT A DEGREE IN GARBOLOGY!