I am not a bioenvironmental engineer, and I hadn’t even heard of this until today, but I did get a BS degree in mechanical engineering and I worked in private industry doing HVAC design for a few years alongside environmental, civil, electrical engineers.
The Wikipedia link someone posted looks pretty informative, but note that the page has “issues” (not sure what). Bioenvironmental engineering sounds like a specialized field of engineering which the military specifically created to fulfill certain needs.
From the Wikipedia link, it sounds like what he military calls bioenvironmental engineering, the rest of the country calls environmental engineering and/or bioremediation, and/or environmental consulting.
Are you sure you want a military career? Consider that if you train and plan to work specifically for the military, if you decide you don’t like it down the line it will not be as easy to get a job in the private sector as it would be the other way around working first for private and then moving over to government. This is somewhat because the military likes to do things “its own way”, has a lot of procedural crap that doesn’t necessarily transfer over to the rest of the world, and it is not trying to turn a profit. I don’t know how else to explain this so I hope it makes sense. Your skills in the private industry will always transfer over to a government job.
On the other hand, benefits are much better with the government. You’ll get more vacation, more sick leave, etc. And, a long career in government sometimes can work to your advantage in the private industry if you have good working relationships with key govt workers – the private industry does appreciate govt connections as permits can sometimes be hard to obtain.
Environmental engineers typically design infrastructure, specifically water and/or wastewater systems. Bioremediation involves using biology to clean up messes (like introducing a bacteria to eat up an oil slick). Environmental consultants will do the hazardous materials testing as well as water testing, air quality testing, etc.