Search results
Results from the WOW.Com Content Network
A septic tank and drainfield combination is a fairly common type of on-site sewage facility in the Western world. OSSFs account for approximately 25% of all domestic wastewater treatment in the US. Onsite sewage facilities may also be based on small-scale aerobic and biofilter units, membrane bioreactors or sequencing batch reactors.
A septic tank is an underground chamber made of concrete, fiberglass, or plastic through which domestic wastewater flows for basic sewage treatment. [2] Settling and anaerobic digestion processes reduce solids and organics, but the treatment efficiency is only moderate (referred to as "primary treatment"). [2]
Gravity separation of solids is the primary treatment of sewage, where the unit process is called "primary settling tanks" or "primary sedimentation tanks". [17] It is also widely used for the treatment of other types of wastewater. Solids that are denser than water will accumulate at the bottom of quiescent settling basins.
A septic drain field, a septic tank, and associated piping compose a septic system. The drain field typically consists of an arrangement of trenches containing perforated pipes and porous material (often gravel ) covered by a layer of soil to prevent animals (and surface runoff ) from reaching the wastewater distributed within those trenches. [ 1 ]
If there is a suitable septic tank in place, pumping the effluent from the tank is the lowest cost option for initial costs. Whether the septic tank is the lowest cost option over time depends on the cost of electricity in the area, how often the tank must be emptied and how much it costs to have the solids pumped out of the tank.
A sewer pipe is normally at neutral air pressure compared to the surrounding atmosphere.When a column of waste water flows through a pipe, it compresses air ahead of it in the system, creating a positive pressure that must be released so it does not push back on the waste stream and downstream traps, slow drainage, and induce potential clogs.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Mesophilic anaerobic digestion (MAD) is also a common method for treating sludge produced at sewage treatment plants. The sludge is fed into large tanks and held for a minimum of 12 days to allow the digestion process to perform the four stages necessary to digest the sludge. These are hydrolysis, acidogenesis, acetogenesis, and methanogenesis.