David, if you discharge septic tank effluent directly into the ocean, there shouldn’t be a problem with drainage. The problem that the sewage from your hotel is creating is pollution of the environment, and a threat to the health of the guests who may be swimming in sewage.
I suggest that you discontinue this dangerous discharge, and install a proper sewage treatment system, utilizing a constructed wetland filter, and a soil absorption system for the final discharge. This type of system can also be designed to recover the valuable nutrients contained in the sewage, and recover the most valuable resource in our society, water. JWA