I have just been working out how to most efficiently maximize my water usage on a small lot I have on a cliff, and it struck me that the most amount of water is consumed flushing. What would the disadvantage be for using seawater for flushing poo? Would it mess with a potential reed bed filtration system to be added downstream of the septic tank? I reckon using salty water instead of fresh water in the toilets would save me way more water.
salt is usually a bad thing for most plants, so i'd avoid it... if you had a completely different reed bed with salt marsh plants but then the salt would be going into the groundwater and then where? you are much better off looking into dry composting (see the humanure handbook) and keep the fresh water for drinking and growing plants.
I would agree with Songbird that using salt water for flushing is a bad idea. As well as the reeds not liking the salt i don't think the septic bugs would be very happy with the salt either, as salt water even at quite low concentrations makes a very good general antiseptic. And just generally it is not a good idea to add salt to any land
Flushing poo with salt water would be a waste of the fertiliser potentials songbird reminds us is worth preserving in the dry composting system. the salt will ruin that potential, and any arable land it ends up in.
Pretty sure most of the metal pieces inside the cistern wouldnt like it either maybe not great for the rubber bits either.
Salt water is a great way to destroy plumbing. A composting toilet will allow you to transform your feces into manure, with little to no water. Thank you kindly.