This is some information I found on the El Dorado County home page that I felt could be very helpful to our clients. Please take a look and let me know if you would like more information like this made avaialble on this site.
HOW DO SEPTIC TANKS WORK IN OUR GRASS VALLEY HOMES?
In the past, wastewater treatment and disposal facilities for homes in Grass Valley with indoor plumbing consisted of buried bottomless containers, or cesspools. Discharge of both solids and liquids to the soils caused the soil pores to clog, and contaminated water entered surface waters and groundwater. Therefore, to protect the soils and reduce public health hazards, septic tanks were installed between the houses and the soil absorption systems. Septic tanks are watertight containers which remove large solids and greases, provide anaerobic digestion of the solids, and storage of the sludge and scum. Septic tanks do not remove large numbers of bacteria and viruses. Septic tanks are constructed of concrete, bricks, clay, or fiberglass. Baffles are placed within the tank to improve solids settling and prevent the scum layer of lightweight solids, fats and greases from floating out of the tank with the effluent. The settled solids are biologically digested by bacteria which live in environments without air (anaerobic bacteria). Some of the products of anaerobic digestion are gases, including methane, carbon dioxide, and hydrogen sulfide, which has an odor similar to that of rotten eggs. The gases are vented from the septic tank through the household plumbing vents. Inorganic and non-biodegradable materials cannot be digested by the microorganisms in the septic tank, and accumulate in the sludge or digested by the microorganisms in the septic tank, and accumulate in the sludge or scum layers. The sludge and scum layers must be removed periodically to prevent the accumulated solids and greases from flowing into the soil absorption system and clogging the soil pores. If washing machines, dishwashers, and garbage disposals are used, the amount of sludge will increase and the septic tank will require frequent cleaning.
This information was pulled from the El Dorado County home page. If you want more information please click here for the full article.