Septic tank
A septic tank is an underground chamber made of concrete, fiberglass or plastic through which domestic wastewater (sewage) flows for basic treatment. Settling and anaerobic processes reduce solids and organics, but the treatment efficiency is only moderate (referred to as "primary treatment"). Septic tank systems are a type of simple onsite sewage facility (OSSF). They can be used in areas that are not connected to a sewerage system, such as rural areas. The treated liquid effluent is commonly disposed in a septic drain field which provides further treatment. However, groundwater pollution may occur and can be a problem.
Cesspit
Before construction reforms were introduced in the early 19th century, liquid waste would seep away through the ground, leaving solid waste behind in the cesspit. While this made removal of solid waste easier, the seeping liquid waste often contaminated well water sources, creating public health problems. Municipal reforms required that cesspits be built of solid walls of stone and concrete. This kept liquid waste in the cesspit, forcing cesspits to be cleaned more frequently, on average two or three times per year. Liquid cesspit waste would be removed with pumps by cesspit cleaners, and then solid waste, valuable as fertilizer and for manufacturing ammonia, was removed. 
In 1846, French public hygienist Alphone Guérard estimated that 100 cesspits were cleaned in Paris every night, by 200-250 total cesspit cleaners in the city, and out of a total of 30,000 cesspits. The replacement of Paris' cesspit system was challenged for decades by officials not on public hygiene grounds, but on economic ones, based on the desire to conserve human waste as fertilizer rather than disposing of it in a modern sewer system. Paris' sewer system began modernizing in the 1880s, with the conversion of storm sewers for public sewage. Some cesspits were still in use in Paris into the 20th century.