Hi, welcome to the forum from Louisiana, glad you joined.
I'm not sure what your septic system looks like or the spraying part. My guess is that the aerobic part is a pump that mixed and stirs the stuff up as it goes into the tank so it is in little bits instead of clumps. That makes it easier for the bugs to break it down. The spraying is probably the treated water.
If the septic system is working properly the water that comes out of it is not contaminated or dangerous. You probably had that system checked when you bought the place. I don't know about Texas or your county but about everywhere I've bought with a septic system (two total, one Arkansas and one Louisiana) that test was required. The key is "working properly", it is possible to have an upset. Maybe you send a big enough slug of bleach through the system to kill the bugs working on that stuff in the septic tank, maybe you have a break that allows a lot of rain water to flush the system before the bugs can do their job, or you have a small tank and you host a big party lasting three or four day so all the people overwhelm the system. Or the tank gets full of slush and needs to be pumped.
Your nose should tell you if it is not working that well but I'd be really reluctant to spray that water on anything I'd eat. I just would not do it. If it's treated water I'd probably be willing to put that on grass or flowers or even under fruit trees as long as it doesn't get on the fruit. My thoughts there are you are in a dry part of Texas and need it for irrigation. Unless I needed the water I would not but you may need it.
I don't know how much I'd trust the people that sell that system. Either their lawyers will say don't use it or their sales people will say, sure, it's OK. In your position I'd probably chat with the county extension agent and see what they have to say. That water should be able to be used safely but I don't know how.
sorry i don't have any experience with that type of septic system and no idea what it might require.
