Question

The pit is typically at least ____________ deep and ___________ across.

(a) 14 meters, 10 m

(b) 30 meters, 15 m

(c) 3 meters, 1 m

(d) 11 meters, 9 m

The question was posed to me by my college professor while I was bunking the class.

This key question is from Design of Septic Tanks in portion Road Estimating, Sanitary and Water Supply Work of Civil Engineering Drawing

Answer 1

Correct option is (c) 3 meters, 1 m

Easiest explanation: The World Health Organization recommends they be built a reasonable distance from the house balancing issues of easy access versus that of smell. The distance from  groundwater and surface water should be as large as possible to decrease the risk of groundwater pollution. The hole in the slab should not be larger than 25 cm (9.8 inches) to prevent children falling in. Light should be prevented from entering the pit to reduce access by flies. This may require the use of a lid to cover the hole in the floor when not in use.