When we located our outhouse at our coastal rainforest cabin we lucked into a really nice scenario where the pit partially fills with water with the bigger rain events, then slowly drains out down under ground as the location is on a bit of a knoll with sloping terrain. Never fills up with too much water (only been splashed once I think in 3 years). The system is beautifully self sustaining and purging. Anyway, my better half has been occasionally adding some kind of BIO enzymes which have done a pretty good job of keeping things liquid. This year somewhat of a mound built up as the fluid drained out and OMG do we have a large black fly issue. I won't even mention what I saw when I shined a flashlight down in there - looked like something out of a horror film with giant fly larvae motoring around all over the place. Anyway, we've had a few flies in the past but just raise the lid and they fly out and are gone and no big deal.
What can I do to mitigate this? Should the priority be to get back to a liquid state, even adding water if necessary to avoid the mound? Should I just get a can of Raid or something and have at it and then worry about reestablishing the friendly bugs after? Hate to introduce something so toxic into the ecosystem there. Is it gonna be get back to liquid and healthy bugs / enzymes and then start hanging fly paper down there? I assume that most out houses have a building mound as normal? How are the flies and larvae normally dealt with?
Yesterday I though I'd just leave the lid up and the door open and hopefully they'd all just fly out - wow that was a really bad idea - went back some hours later and you couldn't have paid me to have a seat anywhere near the place let alone on the throne itself - especially knowing where everyone of those flies came from.... gag me!!!