After I posted my previous reply I remembered a couple more things. On the check valve issue I realized that I had installed two check valves. The one to prevent back flow into the tank is located right by the tanks discharge. The second one is up at the sewer line to prevent the sewer pipe overflow.
Also I designed the plumbing connections to the tank to be easily disconnected in case I needed to repair or change the entire assembly. The connections between the tank and the discharge line and the tubing from the sink drain to the tank are connected by the use of rubber Fernco style couplings which detach by means of loosening the hose clamps which tighten the coupling to the pipe.