The district may:
(1) acquire and provide by purchase, gift, or lease a disposal system in the district or in a county adjacent to the district;
(2) construct and provide a disposal system in the district or in a county adjacent to the district;
(3) operate or sell a disposal system that it constructs or acquires;
(4) contract with a person to operate and maintain a disposal system belonging to the person; and
(5) contract with a person to train or supervise employees of a disposal system.