The authors obtain a threshold-type result on the existence of traveling waves for the following nonlocal and time delayed bio-reactor model: \[ S_t=d_1 S_{xx}-vS_x-f(S)u, \] \[ u_t=u_{xx}-vu_x-ku+e^{-d\tau}\int_{-\infty}^{+\infty}f(S(y-v\tau,t-\tau))u(y-v\tau,t-\tau)f_\alpha(x-y)dy, \] where \(S,u\) denote the nutrient and microbial population, respectively. Assuming that equation \(e^{-d\tau}f(s)=k\) has a unique solution \(S^*>0\) and \(f\) satisfies a few other natural conditions, they show that for each \(S^0>S^*\) there exists \(c^*>0\) such that the system admits a traveling wave solution \((S(x+ct),u(x+ct))\) for each speed \(c>c^*\) satisfying \[ S(-\infty)=S^0>S_0=S(+\infty),\quad u(\pm \infty)=0, \] by employing a fixed-point theorem to solve a bounded domain problem and a limiting argument to pass the domain to \(\mathbb R\). Moreover, \(c^*\) is linearly determined and there is no traveling wave if \(S^0S^*)\) is equivalent to that the basic reproduction number is less (greater) than one. Such results are important in the study of the disease spread and biological invasion.