344 
Theodore Sedgwick Johnson 
Data for Design 
For the purpose of this thesis, the town of Granville, Licking 
County, is chosen, and the design is made as of one part of an 
entire sewer system and disposal plant. 
Locality, Granville, Ohio. Granville is a small residence com- 
munity, the seat of Denison University, and has a resident popu- 
lation of about 1300, which is increased to probably 2000 as a 
maximum during sessions of the University. The soil is of gravel 
and sand, characterized as glacial drift, and has been favorable 
for the long use of cess-pools. 
The town is situated in the watershed of Raccoon Creek, a 
tributary to the Licking River, into which stream it empties at 
Newark, approximately seven miles away. The proximity of 
Newark, through part of which Raccoon Creek flows, together 
with the small flow of the stream at dry seasons, precludes the 
possibility of emptying untreated sewage directly into the stream. 
Some method of purification will then be necessary. This 
thesis assumes the installation of a screen chamber, settling tank 
and intermittent sand filters, and will deal only with the settling 
tank, designing it, however, as a part of this particular disposal 
plant. 
Tributary population. As stated above, the resident popula- 
tion is about 1300, and the present maximum about 2000. It 
will be some time after the introduction of the new system before 
this population will be tributary to the system. The town is 
not a manufacturing or industrial center, and, with the excep- 
tion of the University, cannot be expected to have any great in- 
crease in population, and it would seem that at the end of five 
years a maximum population of 2500 and at the end of ten years 
a population of 3000 would be a generous estimate. The de- 
sign will be based, therefore, on a population of 2500. Another 
factor that would make this figure a conservative one is the 
probability of important changes in methods of sewage disposal 
that may make changes necessary at a later time. 
Character of sewage. The sewage will be that of a residence 
community, as almost no industrial wastes are produced in Gran- 
ville. The sewer system is of the separate type, so no large 
amount of rainfall will reach the sewers. The sewers will be 
laid in gravel deposits, and in almost no case will the grade of 
