Repurposing Old Geothermal Open Loop Drain Field

[Torch Lake Tom]

We recently converted our old open loop geothermal heat pump to an NG furnace. We are on a septic system. I would love to use the old "pump and dump" drain field for draining other equipment that we are currently dumping into our septic such as the water softener, washer, (future) whole house humidifier, and/or water from appliances that currently feed water into a condensate pump. This old drain field is in very sandy soil and serviced a 4 ton geo unit, so I suspect it could handle most or all of the water from these sources. Is there any reason not to use the old open loop drain field for these purposes?
Thanks!