tt-147 BY DON MEEHAN

SEPTIC SYSTEM PERFORMANCE

This time of the year is a time to think about your septic system if you are on one. By the end of November our rainfall should have begun saturating the soil. This fall we have seen about 7 inches, depending on where you are located on the island. Septic systems are marvelous tools when designed, installed, and maintained properly. The County Health Department assures they are designed and installed properly. After that, the maintenance is left up to the home owner. This is not a difficult task and should be thought of every day the system is used. Septic systems are designed to team with soil properties in an aerobic environment. The aerobic environment is a key at this time of the year. Aerobic means there is adequate air present to allow for the growth of bacteria which utilize oxygen for survival. These bacteria and other microorganisms help do the cleaning of the septic effluent. Septic effluent contains a variety of wastes, but the ones which we worry most about are the sewage microorganisms. These organisms are generally able to survive in both oxygen and non-oxygen environments. Septic systems working well will have a high proportion of oxygen dependent soil organisms which are highly competitive against the sewage bacteria. What can you do to assure that your system is operating in an aerobic state? Obviously, you are not able to change the amount of rainfall, but you can evaluate where that rainfall run off from drain gutters and driveways travels. If it is moving through your drainfield area you might want to redirect it. Do not use any black plastic materials over your drainfield. Water use habits in the home can also influence the system. The best use of the system is to have low volume steady use rather than to have very heavy weekend use. This may mean that weekend laundering habits might be changed to doing a load every other day instead. Installation of low volume toilets and bathroom water fixtures helps the system performance since there is less water running through it. Compacting the soil is one of the worst things that can be done since it is so hard to correct. In order for oxygen to get deep into the soil there must be air spaces. These are naturally present in the soils which are acceptable for septic system siting. However, wet weather provides ideal soil compaction conditions. The rule then is to never drive over drainfields; the sin is especially bad in the winter time. For more information about septic system operations and maintenance call or write for our WSU publications.




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