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1950-51 Theatre Catalog, 9th Edition, Page 189 (169)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 189
Page 189

1950-51 Theatre Catalog, 9th Edition, Page 189

Septic Tank Systems for Drive-Ins

The Functional Requirements for an Idea] Type Of Sewage Disposal Are Studied With'Recommendations

BRIEF: The importance of adequate sanitation to sound drive-in operation cannot be unduly emphasized . . . without it, the exhibitor may well had himself plagued by a series of evils . . . including backed-up toilets, frightful odors, and the possibility of a contaminated water supply . . . to say nothing of infuriated patrons and revengeful health authorities.

Such nightmares may . . . however . . . be avoided by the installation of an efficient septic tank system . . . widely deemed to be the most suitable kind of sewage disposal method for drive-ins . . . A good tank installation . . . coupled with a simple filter bed and a bit of intelligent maintenance on the part of the operator . . . should fulfill all of the theatre,s sanitary needs.

Since these is a great lack of knowledge among outdoor theatremen in regard to septic tank systems . . . the Editors of THEATRE CATALOG called upon a well-known expert on drive-in operation for his authoritative views on the subject . . . Based on years of seasoned experience, his discussion covers such topics as: operation . . . location . . . construction and design . . . size requirements . . . maintenance . . . advantages over cesspool . . . distribution box . . . filter bed . . . and dry well.

# One of the most notable problems .of drive-in operation is that of sanitation. Unlike roofed houses, outdoor theatres cannot usually depend on municipal facilities for water supply and sanitation, for they are generally situated in locations that are rather remote from regular sewer systems. Although this sewage disposal problem is one which confronts all drive-ins, it has become increasingly complicated with the construction of larger theatres with capacities of 2,500 to 3,000 patrons.

The most practical and satisfactory method of sewage disposal for a drive-in theatre lies in the use of a septic tank to receive the raw sewage material and some sort of subsurface filter bed to distribute the effluent from the tank.


Strictly speaking, a septic tank is actually a sedimentation tank in which the sludge is retained for a long period of time, during which it undergoes decomposition. The action of the gas bacilli, frequently termed finiaggots," causes the gas-lifted particles of sludge to be raised to the surface of the liquid. In this method of sewage treatment it has been found that only a small amount of sludge collects on the bottom of the tank after it has been in operation for many months, so that it is only necessary



Drive-In Theatre Consultant and Designer

to remove the deposit at two or threeyear periods.

To facilitate decomposition of the sludge it is of vital importance that no surface, soapy, or greasy water be permitted to enter the septic tank. If it is necessary to convey any of these liquids to the filter bed, they should be piped past the septic tank and enter the sewer line on the outlet side of the tank.


The design of any individual sewage disposal system must take into consideration location with respect to Wells or other sources of water supply, topography, water table, soil conditions, area available, and the maximum occupancy of the building served. Adequate plans should be made at the time the theatre is built to erect rest rooms in a location that will be readily accessible to all patrons and suitable for a septic tank system installation.

The septic tank should, furthermore, be located where surface drainage from the site is away from all sources of water supply. The elevation of the tank should be such as to allow suHicient fall in the building sewer lines and proper grading of all lateral lines in the filter bed, thus permitting all field lines to be constructed without excessive cover.

Since septic tanks are usually made of concrete or steel, and the effluence from the tank is, or should be, conducted to the filter bed by means of caulked joints, there is no possible manner in which a well for drinking water can be contaminated. Therefore, the

septic tank is usually placed in close proximity to the fixtures that will drain into it. Caution should be exercised, however, in seeing to it that surface drainage from around the tank site will not reach the vicinity of the water supply.

Where buildings have no basement fixtures or are constructed without basements, as is usually the case with drive in rest rooms, the building drain should be held to an elevation which will permit the tank to be installed without excessive cover. Contemplated finish grades about the building should likewise be checked, so that the top of the tank will not be buried more than 12" to 18" below the surface. In cold climates, if topography permits, the tank may be placed at a greater depth to prevent freezing.

Finally, the location should permit easy access for inspection and cleaning. Low swampy areas or areas which may be subjected to flooding must be avoided. The fact that the tank has, or should have, a reinforced concrete top slab covered with an earth cushion at least' one foot thick protects it from damage by overhead traflic, so that its location need not be controlled because of this factor.

Construction and Design

Septic tanks should be constructed of materials not subject to excessive corrosion or decay. Prefabricated tanks may be acceptable if they embody the recommended features of design and capacity. In many instances, multiple units constructed of sections of large sewer or drain pipe have been installed to meet the capacity requirement. However, as such tanks do not provide for adequate settling or furnish sufficient sludge storage capacity, they are not recommended.

FIGURE 1 Sectional drawing of a recommended septic tank.
1950-51 Theatre Catalog, 9th Edition, Page 189