A system may include a nanobubble generator that uses a shearing force applied by a fluid received through a fluid inlet and a negative pressure applied to an outlet by a pump to provide a vacuum-assisted shear flow nanobubble generator system. In some implementations, the system may include a nanobubble generator including a porous component including a chamber coupled to receive a gas and including a surface having a plurality of gas-permeable openings. The nanobubble generator may include an inlet and an outlet on opposing sides of the porous component to direct the fluid across the openings. The system may include a pump to apply a negative pressure to the outlet of the nanobubble generator. The negative fluid pressure and the fluid flow across the openings cooperate to form nanobubbles at low injected gas pressures, increasing the efficiency of production of nanobubble solutions with pressure sensitive gasses, such as ozone.

A wastewater or sludge treatment fixed film cross-flow distribution media corrugated sheet (84, 84′, 84″) and assemblies (118, 118′, 118″) thereof include corrugations (98, 98′, 98″), angled of about 10° to about 80° to the top and the bottom of the sheet and the assemblies. The sheet has a unitarily formed baffle (100, 100′, 100″) along at least a top portion of an exposed side of the sheet (96, 96′, 96″) or assemblies (130, 130′, 130″) exposed to denser wastewater or sludge outside of the assemblies than within the assemblies that is sufficient, when joined with either a like baffle (100, 100′, 100″) on a like sheet (84, 84′, 84″) or optional substantially planar interstitial sheets (132, 132′, 132″) adjacent the corrugated sheets, to substantially block air used in a sparging system from exiting or the denser wastewater or sludge being treated from entering the exposed side (96, 96′, 96″) of the sheet or the exposed side (130, 130′, 130″) of the assemblies. Beneficial biomass forming biofilm on the surfaces within the assemblies is controlled, effectively treating the wastewater or sludge.