Add punctuation: Preliminary Danish tests show that there is a potential for using this culture of bacteria in an onsite remediation filter
A: Preliminary Danish tests show that there is a potential for using this culture of bacteria in an on-site remediation filter.

Add punctuation: The closest airport for Formentera Playa de Migjorn is
A: The closest airport for Formentera - Playa de Migjorn is:

Add punctuation: 1 Death sitting on a coffin in a churchyard
A:
1. Death sitting on a coffin in a church-yard.