Septic - Home Buying Update

The Preble County Health Inspector came out to make the final decision on the septic tank of the home we are purchasing. Unfortunately, the entire septic needs to be caved in and abandoned. The inspector is requiring that an aeration system be installed with an upflow filter and up to 250' of EQ 36 - I have no idea what most of that means...just copying from the report. If anyone reading has experience with the newer aeration systems, I'd love input. The reason he is requiring this route, rather than a new septic and leach field is because the amount of space we have on that side of our property. Even though we have 1.3+ acres, the house sit on the property in a way that about 25% of the land lays on the septic side and 75% lays on the other side.
We got these results last night and immediately sent the sellers our request for them to replace the septic according to the health inspector's requirements and fix a few other minor issues. At this point, we have offered no additional money, although we are not against sharing some of the costs - we just want to see where they stand. At this point, the ball is in their court - they should have received the request last night around 6:00 PM...so I am hoping that we hear back from them today. We'll let you know.