Septic tanks are a primary transitional treatment structure that utilizes sedimentation and anaerobic fermentation principles to remove suspended organic matter from domestic wastewater. Domestic wastewater contains a large amount of feces, paper fragments, pathogenic parasites, etc., with the concentration of suspended solid particles ranging from 100 to 350 mg/L, and the concentration of organic matter...

CODCR is between 100~400mg/L, with the concentration of suspended organic matter BOD5 ranging from 50~200mg/L. Sewage entering the septic tank undergoes sedimentation for 12~24 hours, which can remove 50%~60% of the suspended solids. The sludge settled out is decomposed by anaerobic fermentation for more than 3 months, converting the organic matter in the sludge into

Stable inorganic matter, easy conversion of raw sludge into stable mature sludge, alters the sludge structure, and reduces its moisture content. Regularly remove and transport sludge for landfilling or use as fertilizer. Requirements: The calculated volume of the sedimentation and decomposition sections of the septic tank should be in accordance with the "Design of Building Water Supply and Drainage."

The "Code for Design of Building Drainage and Sewage Disposal Systems" (GB50015-2003) Articles 4.8.4 to 4.8.7 determine. The retention time of wastewater in a septic tank should be between 12 to 36 hours. For wastewater treatment systems without sludge disposal, the volume of the septic tank should also include the storage volume for sludge.

A septic tank is a device used for treating feces and filtering out sediments. Its principle involves the decomposition of solid matter at the bottom of the tank, with the water-soluble matter rising to the top and flowing into the pipes, preventing blockages. This allows sufficient time for the solid matter (such as feces and garbage) to undergo hydrolysis.

A small treatment facility for separating and sedimenting domestic wastewater and anaerobic digestion of sludge.