  Master equations play a pivotal role in investigating open quantum systems.
In particular, the Bloch-Redfield equation stands out due to its relation to a
concrete physical environment. However, without further approximations it does
not lead to a Lindblad master equation that guarantees that the density matrix
stays completely positive, which has raised some concerns regarding its use.
This study builds on previous efforts to transform the Bloch-Redfield framework
into a mathematically robust Lindblad equation, while fully preserving the
effects that are lost within the secular approximation that is commonly used to
guarantee positivity. These previous approaches introduce two potential
deficiencies: the environment-induced energy shift can be non-Hermitian and
some decay rates can be negative, violating the assumptions of Lindblad's
theorem. Here, we propose and evaluate straightforward solutions to both
problems. Our approach offers an effective and general procedure for obtaining
a Lindblad equation, derived from a concrete physical environment, while
mitigating the unphysical dynamics present in the Bloch-Redfield equation.
