Septic tank
While a properly maintained and located septic tank does not pose any more environmental problems than centralized municipal sewage treatment, certain problems can arise with septic tanks in unsuitable locations. Since septic systems require large drainfields, they are not suitable for densely built areas.
Toilet
A simple pit latrine uses no water seal and collects human excreta in a pit or trench. The excreta drop directly into the pit via a drop hole. This type of toilet can range from a simple slit trench to more elaborate systems with seating or squatting pans and ventilation systems. In developed countries they are associated with camping and wilderness areas. They are common in rural or peri-urban areas in many developing countries. Pit latrines are also used in emergency sanitation situations.