Yes reverse osmosis may ...

Yes reverse osmosis may remove up to 99% max of sulfur but the rotten egg smell may linger on despite.

You may want to find out the origin of your sulfur, usual suspects: industrial, agricultural runoff as well as leaching from old abandoned sites. For your waste water:

for lack of organised minicipal waste disposal try a septic tank where you separate grey from black water and reuse. Grey water: from shower, kitchen and laundry use funnel into a series of pools planted with native grass vegetation soaking up and cleaning the water usually two to three pools/ponds benefitting local wildlife in addition. This grey water may be reused for another round of shower and laundry use. Blackwater store in poop container and re-filter into more containers en suite, then eventually channel into separate leachfield or for use as high concentration plant food into separate pond area where plants take up and fikter this material as well.

good luck ket me know how it goes.