The microorganism preparation feeding method of the invention employs an automatic microorganism preparation feeding apparatus which includes a cold storage apparatus for refrigeration-storing a seed microorganism belonging to the aerobic microorganism group including at least one species of aerobic microorganisms capable of decomposing oil and fat contained in oil/fat-including wastewater and a growth tank for growing the seed microorganism so as to produce the microorganism preparation, wherein the seed microorganism belonging to the aerobic microorganism group is maintained in a live state by means of the cold storage apparatus, the seed microorganism is periodically grown by means of the growth tank so as to produce a predetermined microorganism preparation, and the produced predetermined microorganism preparation is fed to the oil/fat-including wastewater. The method includes refrigeration-storing, as the seed microorganism, a microorganism whose population density is 1×10.sup.7 CFU/mL to 5×10.sup.9 CFU/mL in the cold storage apparatus; growing, as a source material, the seed microorganism of a predetermined volume by means of the growth tank so as to produce the predetermined microorganism preparation whose volume is 50 to 500 times the predetermined volume of the seed microorganism and whose population density is 1×10.sup.7 CFU/mL to 2×10.sup.10 CFU/mL; and feeding the produced microorganism preparation to the oil/fat-including wastewater.

The microorganism preparation feeding method of the invention employs an automatic microorganism preparation feeding apparatus which includes a cold storage apparatus for refrigeration-storing a seed microorganism belonging to the aerobic microorganism group including at least one species of aerobic microorganisms capable of decomposing oil and fat contained in oil/fat-including wastewater and a growth tank for growing the seed microorganism so as to produce the microorganism preparation, wherein the seed microorganism belonging to the aerobic microorganism group is maintained in a live state by means of the cold storage apparatus, the seed microorganism is periodically grown by means of the growth tank so as to produce a predetermined microorganism preparation, and the produced predetermined microorganism preparation is fed to the oil/fat-including wastewater. The method includes refrigeration-storing, as the seed microorganism, a microorganism whose population density is 1×10.sup.7 CFU/mL to 5×10.sup.9 CFU/mL in the cold storage apparatus; growing, as a source material, the seed microorganism of a predetermined volume by means of the growth tank so as to produce the predetermined microorganism preparation whose volume is 50 to 500 times the predetermined volume of the seed microorganism and whose population density is 1×10.sup.7 CFU/mL to 2×10.sup.10 CFU/mL; and feeding the produced microorganism preparation to the oil/fat-including wastewater.

An apparatus for treating fluids such as waste streams with improved aeration efficiency and dual function operation has a blower-assisted aerator, an impeller, a baffle structure circumscribing an air line that includes a first baffle and a second perforated baffle downstream from the first baffle, and a liquid reservoir containing a liquid. The impeller is fully submerged, and located upstream of the fully submerged baffle structure. A fully submerged air outlet is located downstream of the baffle structure, preferably in close proximity to the perforated baffle. When the blower is stopped and the impeller rotating, the baffle structure prevents aspiration into the liquid. In some embodiments, the baffle structure is removably affixed to an air outlet from the blower-assisted aerator, and so may be applied to pre-existing blower-assisted aerators. In some embodiments, one or both of the first and second baffles may resemble flat, domed, cupped, or hemispherical washers.

A mixer configured for releasing large bubbles into wastewater is provided. The mixer can include a central draft tube, an upwardly-extending member surrounding the draft tube, and an accumulator surrounding both the upwardly-extending member and the draft tube. A lower end of the draft tube sidewall may be sealed and not include any openings beneath the lower end of the upwardly-extending member, so as to prevent liquid pumpage through the draft tube. A method for treating wastewater in a system that includes at least one large bubble mixer and at least one fine bubble diffuser is also provided. The large bubble mixer and fine bubble diffuser may be supplied gas independently from one another. The method can include multiple modes of operation wherein gas is either supplied to the mixer, to the diffuser, to neither the mixer or the diffuser, or to both the mixer or the diffuser.

A mixer configured for releasing large bubbles into wastewater is provided. The mixer can include a central draft tube, an upwardly-extending member surrounding the draft tube, and an accumulator surrounding both the upwardly-extending member and the draft tube. A lower end of the draft tube sidewall may be sealed and not include any openings beneath the lower end of the upwardly-extending member, so as to prevent liquid pumpage through the draft tube. A method for treating wastewater in a system that includes at least one large bubble mixer and at least one fine bubble diffuser is also provided. The large bubble mixer and fine bubble diffuser may be supplied gas independently from one another. The method can include multiple modes of operation wherein gas is either supplied to the mixer, to the diffuser, to neither the mixer or the diffuser, or to both the mixer or the diffuser.

Provided is a wastewater treatment system. The wastewater treatment system includes an equalization (EQ) tank which receives contaminated wastewater having a high nutrient content from a plant, a dissolved air flotation (DAF) system and an on-site oxygen generation system which provides gas phase oxygen to the wastewater treated in the equalization (EQ) tank and/or the dissolved air flotation (DAF) system. The dissolved air flotation system includes at least one air dissolved air flotation vessel which may house an aerator grid assembly having a perforated lateral diffuser and optionally, a primary aerator assembly.

Systems and methods for providing aeration and mixing to a substance in a containment unit are disclosed.

A water treatment system for aeration of water in a treatment tank includes at least one bridge extending above an upper surface of the water in the tank; a retrievable mounting frame assembly, including a frame, a plurality of aeration elements, a plurality of mounting brackets to secure the aeration elements to the frame, a control arm having secured to the frame at the first end, and a first air distribution conduit coupled to the aeration elements for supplying an air flow to the aeration elements; at least one guide rail system secured to the bridge assembly and extending to the floor of the tank, the guide rail system having at least one or multiple parallel guide rails, a second air distribution conduit coupled to the first air distribution conduit, and an actuatable push-rod positioned between the guide rails and connected to the control arm's second end. The hold-down rod, when actuated, moves the mounting frame assembly along the guide rails from a first position above the upper surface of the water and into a second position on the floor of the tank for aeration of the water. A transport device and a transferrable lifting crane for positioning the frame assembly are moveable along the length of the bridge along guide tracks provided in the bridge.

A water treatment system for aeration of water in a treatment tank includes at least one bridge extending above an upper surface of the water in the tank; a retrievable mounting frame assembly, including a frame, a plurality of aeration elements, a plurality of mounting brackets to secure the aeration elements to the frame, a control arm having secured to the frame at the first end, and a first air distribution conduit coupled to the aeration elements for supplying an air flow to the aeration elements; at least one guide rail system secured to the bridge assembly and extending to the floor of the tank, the guide rail system having at least one or multiple parallel guide rails, a second air distribution conduit coupled to the first air distribution conduit, and an actuatable push-rod positioned between the guide rails and connected to the control arm's second end. The hold-down rod, when actuated, moves the mounting frame assembly along the guide rails from a first position above the upper surface of the water and into a second position on the floor of the tank for aeration of the water. A transport device and a transferrable lifting crane for positioning the frame assembly are moveable along the length of the bridge along guide tracks provided in the bridge.

A system for mixing and mixing processes and structures are disclosed. In addition a nozzle used for mixing is disclosed.