Risers on septic tank - filter inspection lid

[Mihomeowner]

My septic tank was 2 feet under so I installed some risers on the 24 inch lids. Everything went well until I found out when they came and pumped it there is a third lid.. an inspection lid for the filter. It's a small lid, I want to say 6 or 8 inches.

Talking to the guys that pumped my tank, they said the best thing would be to rig up a riser using some 8" PVC piping. Sounds good... but where can I get this stuff, and what kind of lid should I put on the top? Unlike my main risers that came with separate lids and I permanently removed the cement ones... I am going to leave the cement lid on the filter inspection port. There fore, I just need a lid/cap device that will keep dirt out.

Someone please point me in the right direction! Thanks

 

[Smooky]

It sounds like you have a basic septic tank with a filter. The filter should be in the last compartment. Each compartment is required to have a lid. If the tank has a baffle wall inside there may be a small lid over the top of the baffle to make sure there is a vent between the compartments. The link below is the Michigan criteria for on-site wastewater.

Starting about page 40
11.5.3 Effluent Filters
11.6 Access Risers and Lids
http://michigan.gov/documents/deq/MIC_Chpt_01-14_final_edited_draft_01-29-13_411944_7.pdf

 

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[Mihomeowner]

If I use 10" PVC for this, how do I secure the top? What kind of "cap" would I put in, something threaded?