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Cesspools

Before septic tanks were common, sewage from homes was often disposed of in covered vertical pits called cesspools. The cesspool was an early predecessor of the current-day septic system, providing a subsurface system for disposal of waterborne sewage.  The use of cesspools was primarily driven by convenience, and their location was governed mainly by the nearest available land.  Sometimes cesspools were constricted in the basements of urban buildings. 

Cesspools are now viewed as undesirable by public health officials, due, in part to historical experiences with overused and failed systems as well as increased concerns for groundwater protection.  In most areas, cesspools are prohibited by local health and building codes. 

Process Description

Design Criteria

Operation & Maintenance

 

Process Description

A typical cesspool is a cylindrical hole in deep soil, several feet in diameter.  There is usually a porous inner wall of stone, masonry, precast concrete rings, or other material strong enough to shore up the soil.  The outer surface (between the masonry wall and the outer soil wall) is filled with gravel.  There is a concrete lid and, on top of that, soil is backfilled to grade.

Raw wastewater flows into the top of the inner chamber.  The inner chamber retains and partially digests the solids, and the effluent seeps through to the gravel-filled outer chamber, and then into the surrounding soil. 

 

Design Criteria

Design of cesspools depends upon the ability of the soil to absorb water.  They should not be used in porous soil or where groundwater may come to within five feet of the bottom.  They should also be downhill and 500 feet away from wells or springs used for drinking water.

Figure 1. Cesspool.

 

Operation & Maintenance

The system is designed to provide treatment and disposal for normal domestic sewage.  No non-biodegradable material should be introduced into the wastewater treatment and disposal system.  Plastic and paper (except toilet paper) are examples of non-biodegradable materials that should not be placed down the drain.  Normal amounts of dirt and small non-biodegradable debris (buttons, dental floss, etc.) from washing will inevitably get into the system.  These solids will be retained in the septic tank until it is pumped during its normal maintenance.   Oils and grease should not be placed down the drain in excess quantities. Normal washing of greasy dishes is not considered excessive.  Routinely draining fat from a frying pan, deep fryer, or roasting pan down the drain would be considered excessive.

Because cesspools are generally unacceptable, no specific operation and maintenance procedures have been developed.