Poor quality of groundwater -> Brine heat pump?

Hello everyone,

Actually, we wanted to install a groundwater pump for our new building (Kfw 70). The costs for developing this heat source would be acceptable due to the high groundwater level of 2.5 m. Our neighbors each drilled about 7-8 m.

However, as I learned from the district office today, the water quality does not seem to be really optimal for a water heat pump.
Mn: 0.13 mg/l
Fe: 3.2 mg/l

I don’t know if we should risk a "conventional" groundwater pump here.

Do you know of any alternatives on how to use groundwater with this poor quality for heating?

Would, for example, energy baskets of around 5 m be an alternative? These would reach into the groundwater and could always extract energy from the water here as well. According to the district office, such a solution would also be approved.

Other heating methods besides the brine or groundwater heat pump are basically not an option for us.
air heat pump: noise?, cost-efficient operation with rising electricity prices?
Gas: uneasy feeling, fossil fuel
Pellets: no storage space due to no basement (because of high groundwater level)
Brine deep drilling is not approved
Brine surface collector: probably too little area

Best regards,
Felix Demmelhuber