Abstract: Storage tanks, for example, underground septic tanks, and their methods of fabrication are provided. The tanks include a substantially liquid impermeable plastic vessel having a top, a bottom, and sides; a concrete container encasing and retaining the plastic vessel, the concrete container contacting the bottom and at least partially contacting the sides of the plastic vessel; and at least one opening for receiving effluent, for example, waste effluent, into the plastic vessel. The methods of fabricating the tanks include positioning a plastic vessel into an enclosure; introducing concrete into the enclosure about the plastic vessel; allowing the fluid concrete to cure to provide a substantially solid concrete container about the plastic vessel; and removing the plastic vessel having a concrete container from the enclosure. Vessel shape retaining devices are also disclosed. Aspects of the invention are uniquely adapted to underground storage.

Abstract: Storage tanks, for example, underground septic tanks, and their methods of fabrication are provided. The tanks include a substantially liquid impermeable plastic vessel having a top, a bottom, and sides; a concrete container encasing and retaining the plastic vessel, the concrete container contacting the bottom and at least partially contacting the sides of the plastic vessel; and at least one opening for receiving effluent, for example, waste effluent, into the plastic vessel. The methods of fabricating the tanks include positioning a plastic vessel into an enclosure; introducing concrete into the enclosure about the plastic vessel; allowing the fluid concrete to cure to provide a substantially solid concrete container about the plastic vessel; and removing the plastic vessel having a concrete container from the enclosure. Vessel shape retaining devices are also disclosed. Aspects of the invention are uniquely adapted to underground storage.

Abstract: Storage tanks, for example, underground septic tanks, and their methods of fabrication are provided. The tanks include a substantially liquid impermeable plastic vessel having a top, a bottom, and sides; a concrete container encasing and retaining the plastic vessel, the concrete container contacting the bottom and at least partially contacting the sides of the plastic vessel; and at least one opening for receiving effluent, for example, waste effluent, into the plastic vessel. The methods of fabricating the tanks include positioning a plastic vessel into an enclosure; introducing concrete into the enclosure about the plastic vessel; allowing the fluid concrete to cure to provide a substantially solid concrete container about the plastic vessel; and removing the plastic vessel having a concrete container from the enclosure. Vessel shape retaining devices are also disclosed. Aspects of the invention are uniquely adapted to underground storage.

Abstract: Storage tanks, for example, underground septic tanks, and their methods of fabrication are provided. The tanks include a substantially liquid impermeable plastic vessel having a top, a bottom, and sides; a concrete container encasing and retaining the plastic vessel, the concrete container contacting the bottom and at least partially contacting the sides of the plastic vessel; and at least one opening for receiving effluent, for example, waste effluent, into the plastic vessel. The methods of fabricating the tanks include positioning a plastic vessel into an enclosure; introducing concrete into the enclosure about the plastic vessel; allowing the fluid concrete to cure to provide a substantially solid concrete container about the plastic vessel; and removing the plastic vessel having a concrete container from the enclosure. Vessel shape retaining devices are also disclosed. Aspects of the invention are uniquely adapted to underground storage.

Abstract: Storage tanks, for example, underground septic tanks, and their methods of fabrication are provided. The tanks include a substantially liquid impermeable plastic vessel having a top, a bottom, and sides; a concrete container encasing and retaining the plastic vessel, the concrete container contacting the bottom and at least partially contacting the sides of the plastic vessel; and at least one opening for receiving effluent, for example, waste effluent, into the plastic vessel. The methods of fabricating the tanks include positioning a plastic vessel into an enclosure; introducing concrete into the enclosure about the plastic vessel; allowing the fluid concrete to cure to provide a substantially solid concrete container about the plastic vessel; and removing the plastic vessel having a concrete container from the enclosure. Vessel shape retaining devices are also disclosed. Aspects of the invention are uniquely adapted to underground storage.