WASTEWATER TREATMENT SYSTEMS AND METHODS

Abstract

The instant disclosure is directed towards methods of treating wastewater and related systems, where the system includes: a first zone comprising at least one anaerobic tank, and a second zone comprising at least one engineered wetland. In some embodiments, the system includes a third zone comprising at least one bauxite residue cell.

Claims

1. A method of treating wastewater, comprising: flowing a wastewater stream through at least one anaerobic settling and treatment tank, wherein the anaerobic settling and treatment tank comprises: a bottom and at least one sidewall, an influent end and an effluent end in liquid communication with a control volume in the tank, wherein the control volume is configured to retain wastewater; wherein the tank further comprises a baffle configuration, including: a baffle located adjacent to the influent end and configured to distribute the flow of wastewater into the tank; and at least one member configured between the baffle and the effluent end wall, wherein the member configured to promote mixing and flow distribution of the wastewater, and a settling promoter configured along the effluent end sidewall and configured to promote settling of solids prior to discharge from the effluent end; wherein the baffle configuration is configured to flow wastewater through the tank along at least one predetermined flow path at a surface overflow rate of at least 0.25 m/hr; and treating the wastewater in the anaerobic settling and treatment tank via the baffle configuration and surface over flow rate to remove at least 75% of organics from the wastewater stream to provide a low organics wastewater stream; flowing a low organics wastewater stream into an engineered wetland from the anaerobic settling treatment tank effluent, wherein the engineered wetland is in liquid communication with the anaerobic settling and treatment tank; aerating the low organics wastewater stream, wherein aerating the low organics wastewater is sufficient to sustain aerobic bacteria; treating the low organics wastewater stream in the engineered wetland to remove: ammonia from the low organics wastewater to a content of not greater than 8 ppm, wherein the engineered wetland comprises a pore water hydraulic retention time of not greater than 4 days; discharging a treated water stream from the engineered wetland.

2. The method of claim 1, wherein the settling promoter comprises an angle baffle configured to the sidewall proximate an effluent end.

3. The method of claim 1, wherein the settling promoter comprises a discontinuous region along the at least one sidewall proximate an effluent end.

4. The method of claim 1, wherein the anaerobic settling tank comprises a plurality of members spaced apart from one another, between the baffle and the settling promoter.

5. The method of claim 4, further comprising three members, spaced equidistant from each other and comprising the same angled position within the tank, wherein the three members are located proximate to a lower end of the tank.

6. The method of claim 1, wherein aerating comprises aerating the low organics wastewater at a rate of at least 1.1 scfm/gpm wastewater.

7. The method of claim 6, wherein aerating is sufficient to sustain a dissolved oxygen content of at least about 80% of saturation of the low organics wastewater at a given temperature.

8. The method of claim 1, wherein the engineered wetland is comprises a pore water hydraulic retention time of at least about 0.25 day.

9. The method of claim 1, further comprising, prior to the discharging step: flowing a low nitrogen wastewater stream from the engineered wetland to an inlet of at least one polishing cell having media including bauxite residue, where the cell is in liquid communication with the engineered wetland, wherein the polishing cell comprises at least one sidewall, an inlet and an outlet configured to encase the media within the cell, wherein the cell is configured to permit the low nitrogen wastewater stream to flow therethrough via the inlet and outlet, and treating the low nitrogen wastewater via the via the media to remove at least about 30% pathogens from the low nitrogen wastewater; and flowing a polished water stream from the effluent from the cell.

10. The method of claim 1, further wherein the system comprises a hydraulic retention time of at least 12 hours to not greater than 6 days.

11. A method comprising: analyzing a wastewater stream to determine a contaminant profile, the contaminant profile comprising: at least one contaminant; selecting a target cleaned water stream profile, wherein the cleaned water stream profile comprises upper limits of the quantities of contaminants present in the contaminant profile; and selecting, based on the target cleaned water stream profile and the contaminant profile of the wastewater stream, a number of tank modules, based on the contaminant profile; selecting, based on the target cleaned water stream profile and the contaminant profile of the wastewater stream, a number of engineered wetland modules, based on the contaminant profile; selecting, based on the target cleaned water stream profile and the contaminant profile of the wastewater stream, a number of bauxite residue modules, based on the contaminant profile; configuring a wastewater treatment system, where the system comprises a first zone having the number of tank modules, a second zone comprising the number of engineered wetland modules, and a third zone comprising the number of bauxite residue modules to define a wastewater flow path; flowing the wastewater stream through the flow path defined by the first zone, the second zone, and the third zone of the system; treating the wastewater via the system to remove contaminants via the first zone, the second zone, and the third zone; and discharging a cleaned water stream, wherein the cleaned water stream comprises a cleaned water stream profile which corresponds to the target cleaned water stream profile.

12. The method of claim 11, further comprising: replacing at least one module of the tank modules, wetland modules, or bauxite residue modules after a predetermined amount of time.

13. The method of claim 12, further comprising: replacing at least one module of the tank modules, wetland modules, or bauxite residue modules after a predetermined amount of wastewater has been treated.

14. The method of claim 12, further comprising monitoring at least one module in the wastewater treatment system to assess the effectiveness of the module.

15. The method of claim 12, further comprising moving at least one module via a transport device configured to the module to allow mobility of the module.

16. The method of claim 15, wherein the transport device is selected from the group consisting of: wheels, a track and wheels, a plurality of rollers, a conveyor belt, and combinations thereof.

17. The method of claim 11, connecting the plurality of modules in the system via connection ports as the inlet and outlet.

18. A method of treating wastewater, comprising: flowing a wastewater stream through at least one anaerobic settling and treatment tank, wherein the anaerobic settling and treatment tank comprises: a bottom and at least one sidewall, an influent end and an effluent end in liquid communication with a control volume in the tank, wherein the control volume is configured to retain wastewater; wherein the tank further comprises a baffle configuration, including: a baffle located adjacent to the influent end and configured to distribute the flow of wastewater into the tank; and at least one member configured between the baffle and the effluent end wall, wherein the member configured to promote mixing and flow distribution of the wastewater, and a settling promoter configured along the effluent end sidewall and configured to promote settling of solids prior to discharge from the effluent end; wherein the baffle configuration is configured to flow wastewater through the tank along at least one predetermined flow path at a surface overflow rate of at least 0.25 m/hr; and treating the wastewater in the anaerobic settling and treatment tank via the baffle configuration and surface over flow rate to remove at least 75% of organics from the wastewater stream to provide a low organics wastewater stream; flowing a low organics wastewater stream into an engineered wetland from the anaerobic settling treatment tank effluent, wherein the engineered wetland is in liquid communication with the anaerobic settling and treatment tank; aerating the low organics wastewater stream, wherein aerating the low organics wastewater is sufficient to sustain aerobic bacteria; treating the low organics wastewater stream in the engineered wetland to remove ammonia from the low organics wastewater to a content of not greater than 8 ppm to provide a low nitrogen wastewater stream, wherein the engineered wetland comprises a pore water hydraulic retention time of not greater than 4 days; flowing the low nitrogen wastewater stream from the engineered wetland to an inlet of at least one polishing cell having media including bauxite residue, where the cell is in liquid communication with the engineered wetland, wherein the polishing cell comprises at least one sidewall, an inlet and an outlet configured to encase the media within the cell, wherein the cell is configured to permit the low nitrogen wastewater stream to flow therethrough via the inlet and outlet, and treating the low nitrogen wastewater via the via the media to remove at least about 30% pathogens from the low nitrogen wastewater; and discharging a treated water stream from the engineered wetland.

19. The method of claim 18, further wherein the system comprises a hydraulic retention time of at least 12.5 hours to not greater than 6.5 days.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0185] FIG. 1 depicts and flow chart of an embodiment of a wastewater treatment system in accordance with the instant disclosure.

[0186] FIG. 2A depicts a top plan view of an embodiment of a second zone, or an engineered wetland, in accordance with the instant disclosure.

[0187] FIG. 2B depicts a side plan view of the engineered wetland of FIG. 2A.

[0188] FIG. 2C depicts a close-up cut-away side plan view of the engineered wetland of FIG. 2B.

[0189] FIG. 3A depicts an embodiment of a perforated aeration pipe usable in accordance with an embodiment of a second zone of the instant disclosure.

[0190] FIG. 3B depicts an embodiment of an aeration system of an engineered wetland, including several aerations lines anchored via grating (e.g. grating supports).

[0191] FIG. 4 depicts a cut-away perspective view of an embodiment of a portion of an aeration system in a second zone of a wastewater treatment system in accordance with the instant disclosure.

[0192] FIG. 5 depicts a close-up cut away perspective view of the embodiment depicted in FIG. 4.

[0193] FIGS. 6A-6C depicts various perspective side views of portions of the aeration system depicted in FIG. 5. FIG. 6A is a cut-away perspective view of an embodiment of the drop down aeration lines stemming from the piping. FIG. 6B is a partial cut-away perspective view of FIG. 6A, showing a close-up of the upper portion of the drop down aeration lines stemming from the piping. FIG. 6C is a partial cut-away perspective view of FIG. 6A, showing a close-up of the upper portion of the drop down aeration lines stemming from the piping, depicting a different perspective than that depicted in FIG. 6B.

[0194] FIG. 7A depicts an embodiment of a third zone (e.g. bauxite residue cell) in accordance with the instant disclosure.

[0195] FIG. 7B depicts a cut away side view of an embodiment of a bottom portion of the third zone (e.g. bauxite residue cell) of FIG. 7A.

[0196] FIG. 8 depicts a top plan view of an embodiment of the third zone of the instant disclosure, including a plurality of bauxite residue cells configured in parallel to one another and connected to receive wastewater and disperse cleaned water.

[0197] FIG. 9 depicts a top plan view of one embodiment of the system of the instant disclosure.

[0198] FIG. 10 depicts a cut-away side view of the embodiment of the wastewater treatment system depicted in FIG. 9.

[0199] FIG. 11A depicts a cut-away side view an embodiment of an anaerobic settling tank in accordance with the instant disclosure (e.g. referenced as Tank 3 in the Examples section).

[0200] FIGS. 11B through 11G depict alternative embodiments of the baffle configuration of the anaerobic settling and treatment tank in accordance with the instant disclosure.

[0201] FIG. 11B depicts a hockey stick-shaped baffle, a single member angled in the same manner as the hockey stick shaped baffle, and a settling promoter (e.g. angle baffle attached to the sidewall).

[0202] FIG. 11C depicts a hockey stick shaped baffle, two members angled in the same manner as the lower end of the hockey stick shaped baffle, and spaced equidistant from each other, with a third member located above the first two members (e.g. in the mixing zone and angled in an obtuse direction when compared to the plane of the bottom of the tank), and a settling promoter that is a baffle positioned in an angled direction (e.g. acute angle).

[0203] FIG. 11D depicts a hockey stick shaped baffle adjacent to the inlet, followed by two members positioned at different heights from each other relative to the depth of the tank, with a settling promoter attached to the sidewall and positioned in an obtuse angle when compared to the plane created by the bottom of the tank.

[0204] FIG. 11E depicts a hockey stick shaped baffle, a very large member (lengthwise) having a different angle than the lower portion of the hockey stick shaped baffle, where the member crosses a substantial portion of the mixing volume of the tank, and a settling promoter angled in an acute angle from the sidewall with a top portion having an angle close to 0 degrees.

[0205] FIG. 11F depicts a hockey stick shaped baffle, with two members having an angle close to 0 degrees (e.g. 5 degrees, and spaced equidistantly from each other), with a settling promoter located on the effluent sidewall adjacent to the outlet.

[0206] FIG. 11G depicts a hockey stick shaped baffle, with two members having an angle close to 0 degrees (e.g. 5 degrees, and spaced equidistantly from each other), with a settling promoter located on the effluent sidewall adjacent to the outlet, where this embodiment depicts larger-sized members and larger-sized settling promoter than in the embodiment depicted in FIG. 11F.

[0207] FIG. 12A depicts a series of columns having different media which were run in accordance with an experimental example.

[0208] FIG. 12B depicts the measured characteristics of each column, including porosity, empty bed contact time (EMCT), and hydraulic retention time (HRT). FIG. 13 is a graphical result of the measured effluent fecal coliform over time for the five different column experiments depicted in FIG. 12A over a span of 151 days, where the measure fecal coliform is an indicator of pathogen presence/pathogen removal.

[0209] FIG. 13 shows the effluent fecal coliform concentrations for each column versus time through the course of the study. The sand control column exhibited a lag in disinfection performance, as indicated by the high effluent concentration in the first six data points (to the left of the first dotted line); the remaining columns performed more consistently over the course of the pilot, exhibiting no low-removal startup period. When the flow rate was doubled, (i.e. the right side of the second dotted line) fecal coliform effluent concentration tended to increase slightly in all columns, as empty bed contact time was reduced from about 624 minutes to about 300 minutes per column.

[0210] FIG. 14 is a graphical result depicting the average effluent fecal coliform at various concentrations (e.g. all data, 20 mL/min, and 10 mL/min (with sand lag removed), where fecal coliform values are indicators for pathogen contaminants.

[0211] FIG. 15 depicts the average % removal of pathogens (as indicated by fecal coliform) for the different media columns of FIG. 12A. Sand had an average of 83.1% removal of pathogens; bauxite residue had an average of 94.2% removal of pathogens; bauxite residue and 2.5 wt. % zero valent iron had an average of 94.5% removal of pathogens; compost, followed by sand with 2.5 wt. % ZVI had an average of 94.9% removal of pathogens; and compost followed by bauxite residue having 2.5 wt. % ZVI had an average removal of 99.1% removal of pathogens.

[0212] FIG. 16 depicts a graph of Pathogen Removal (indicated by Fecal Coliform Removal (%)) in three different columns, showing that the column having pelletized BR with 2.5 wt. % ZVI had 78.52% removal; the column having bauxite residue had 77.97% removal; and the column having bauxite residue and 2.5 wt. % ZVI had 80.52% removal.

[0213] FIG. 17 depicts a schematic of a cut-away sideview of a bauxite residue module, in accordance with the instant disclosure.

[0214] FIG. 18 depicts the computational flow dynamics of an anaerobic tank having a baffle configuration of the instant disclosure compared to a tank having conventional baffle configuration, where the dashed lines are representative of a velocity profile of water through the tanks, illustrative of the water movement through the tank and dead zones or static areas.

DETAILED DESCRIPTION

[0215] The present disclosure provides systems and methods of effectively treating a wastewater stream to disinfect the water and remove other contaminants from the water. Removal of contaminants, other than microorganisms, may include the removal of ammonia, biodegradable organics (e.g. BOD, CBOD), TSS, VSS, oils, greases, phosphorus, metals, pharmaceuticals, and personal care products. Reference will now be made in detail to the accompanying drawings, which at least assist in illustrating various pertinent embodiments of the present invention.

[0216] Referring to FIG. 1, a schematic of an embodiment of the wastewater treatment system 10 of the instant disclosure is depicted. The system 10 depicts an inlet 12, an outlet 14, and a first zone 40, second zone 60, and third zone 100, which are in liquid communication with each other, as depicted via arrows between zones. Wastewater 26 is directed into the system via inlet 12.

[0217] Then, the wastewater 26 travels from the inlet 12 into the first zone 40, which is at least one anaerobic settling and treatment tank 42. The anaerobic settling/treatment tank 42 is configured to remove particulates and sludge from the wastewater and remove/reduce biodegradable organics. Next, the wastewater 26 is directed from the outlet 58 of the first zone 40 to the inlet 66 of the second zone 60, which is at least one engineered wetland 62.

[0218] The engineered wetland 62 includes media 68 and vegetation (plants) 70 retained in the wetland and/or rooted in the media 68. Also, the engineered wetland 62 is aerated via an aeration system 90 in communication with the engineered wetland 62 via piping 84. In some embodiments, the engineered wetland 62 is configured to receive organics (e.g. methanol, woodchips, molasses, etc.) from an organic feed chamber 78 (depicted, e.g. in FIG. 9). In some embodiments, the organic feed chamber 78, which is adapted to be in liquid communication with the engineered wetland 62. (see, e.g. FIG. 9, 10.) In the second zone 60, the wastewater 62 is disinfected and contaminants are removed therefrom. The wastewater 26 is then directed out of the second zone 60 via the outlet 74 and into the third zone 100 via the inlet 114.

[0219] The third zone 100 comprises at least one bauxite residue cell 102. The bauxite residue cell 102 includes media 108 therein. In some embodiments, the media 108 comprises bauxite residue. In some embodiments, the media consists essentially of bauxite residue. In some embodiments, the media 108 comprises bauxite residue and ZVI in a particular weight ratio. In some embodiments, the media 108 comprises a mixture of bauxite residue and ZVI.

[0220] In some embodiments, in the bauxite residue cell 102, the wastewater 26 is disinfected and is treated to remove (if present), as non-limiting examples, contaminants including: ammonia, phosphorous, heavy metals, pharmaceuticals, and personal care products. Cleaned water is then directed out of the bauxite residue cell 102 via outlet 116. Cleaned water then exits the system 10 via the outlet 14. In some embodiments, the outlet 116 from the bauxite residue cell 102 is the same as the outlet 14 from the wastewater treatment system.

[0221] FIGS. 2A through 3B are directed towards an embodiment of the second zone 60, at least one engineered wetland 62. Referring to FIGS. 2A-2C, wastewater 26 enters the wetland 62 via inlet 66, and is aerated by air directed into the engineered wetland via piping 84, which is located along the bottom portion of the vessel 64. While wastewater 26 is retained in and travels through the wetland 62, it is aerated via air coming through the piping 84 and it is directed through the media 68 and plant roots of the plants rooted in the media 68.

[0222] Referring to the aeration system 90, the piping 84 is located along the bottom portion of the wetland 62, and is configured with a plurality of perforations to distribute air into the wastewater 26. Diffusers 88 cover the perforations in the piping 84 and are configured to diffuse the gaseous air into the wastewater 26. A grate 76 (including the grate and support) supports the piping 84 to prevent the media 68 from crushing the piping 84. FIG. 3A shows a close-up of a curved portion of piping 84 having perforations 86 therein. FIG. 3B depicts the portions of piping 84 anchored via grate 76 into the bottom of the vessel 64.

[0223] Referring to FIGS. 4-6C, another embodiment of an engineered wetland 62 is depicted. As shown in FIGS. 4 and 5, the configuration of the vessel 64, inlet 66 and outlet 74 are similar, while the aeration system 90, including the piping 84 and diffusers 88, are in a different configuration. Here, the piping 84 is directed across the top of the vessel 64, with individual aeration lines which are retained into secondary pipes 92. The secondary pipes 92 are connected to the piping 84 via plugs 94 to prevent water from flowing into the secondary pipes 92 and pipes 84. In some embodiments, the pipes 84 are removable and/or the incoming air supply/level of aeration is variable to adjust the amount of aeration in the wetland. FIGS. 6A, 6B, and 6C each depict close-up perspective views of the drop down aeration lines stemming from the piping 84.

[0224] FIGS. 7A and 7B depict an embodiment of the third zone, comprising at least one bauxite residue cell 102. Referring to FIGS. 7A and 7B, a modular bauxite residue cell is depicted. In some embodiments, the sidewall of the module completely encases the inner void of the bauxite residue cell 102, where the media 108 is housed. Wastewater 26 is directed into and out of the cell 102 via inlet and outlet, which are in liquid communication with the inner void. In some embodiments, the cell 102 is equipped with supports (e.g. on each side) to enable the module to be moved/adjusted. In some embodiments, supports comprise wheels, a wheel and track configuration, a stand (e.g. which allows for a lift to move/remove the cell 102), and combinations thereof. Referring to FIG. 7A, the bauxite residue cell 102 includes distributor plates (e.g. baffles) 110 towards the bottom portion of the cell 102, where each distributor plate 110 includes perforations therein 112 to permit wastewater 26 to flow there through. In some embodiments, the distributor plates are configured to disperse wastewater as it enters the bauxite residue cell via the inlet 114. In some embodiments, the distributor plates are off-set from each other such that the perforations do not line up. FIG. 7B depicts the inlet 114 at the base of the cell 102 vessel 104, illustrating that this embodiment is for an up-flow configuration (e.g. reverse gravity). Also depicted in FIG. 7B is the connection port 122, which is configured to allow for a quick connect/disconnect of the bauxite residue cell module from the inlet 114 and outlet 116 (e.g. so that another module can replace it).

[0225] Referring to FIG. 8, a plurality of bauxite residue cells 102 are arranged in parallel to one another on top of a support 118 to enable wastewater 26 to be fed from an inlet 114 at the base of each module (see, e.g. FIG. 7B). Further, a pump 120 is depicted, for pumping the wastewater 26 in an up-flow configuration. Once the water is cleaned, it exits the cells 102 via piping and is directed to the outlet 116 of the third zone of the bauxite residue cell/module system.

[0226] Without being bound to a particular mechanism or theory, the function of the anaerobic settling tank (e.g. septic tank) is believed to be the breaking down/removal of organic matter by anaerobic bacteria contained in the tank sludge. Settling of suspended solids, organic and inorganic solids are removed in this first zone.

[0227] Without being bound by a particular mechanism or theory, it is believed that the function of engineered wetland A is for additional removal of BOD, using aerobic bacteria (e.g. the wetland is aerated) and to provide nitrification (conversion of ammonia to nitrate), via the aerobic bacteria. Without being bound to a particular mechanism or theory, the function of the engineered wetland portion of the treatment is believed to be BOD removal, nitrification/denitrification, and additional TSS removal from the wastewater.

Example 1

Example of a Wastewater Treatment System

[0228] Referring to FIGS. 9 and 10, schematics for an embodiment of a wastewater treatment system is depicted. This schematic was constructed and operated as a pilot for this Example. In each tank (three shown), the design HRT is 0.25 to 1 day at an influent flow rate.

[0229] Within each tank, there is an upflow region and a down flow region. Each tank contains 3 chambers (1 chamber consisting of a down flow section followed by an up flow section). The separate chambers and baffles direct the flow of water, allowing for better contact between the wastewater and the anaerobic bacteria in the sludge (i.e. high concentration sludge zone located proximate to the bottom of the tank.) The up flow chambers are sized so that the up flow velocity is 0.25 m/hr at an influent flow rate of 1 gpm.

[0230] Tank 1&2 each contain a baffle configuration which is a hockey stick design (i.e. two baffles, each with a generally straight portion and each straight portion having an angled section at its end). Tanks 1 &2 are piped in series, so that the effluent from Tank 1 is the influent to Tank 2, testing removal efficiency of 6 total chambers.

[0231] Referring to FIG. 11, Tank 3 is depicted, which includes a baffle configuration including a hockey stick-shaped baffle, three members (vane baffles) and a settling promoter (e.g. located on the sidewall closest to the outlet). The baffle configuration was based upon computer modeling experiments (see, e.g. Example 5). This tank has 3 different types of baffles that cooperate as one structure. The suspended baffle is closest to the inlet and is configured to separate the down flow from the up flow section. The suspended baffle comprises a hockey-stick shape, with a straight portion (e.g. generally vertical, perpendicular to the bottom of the tank) and a bottom portion which is curved. Also, there are three separate members that are configured to act as turning vane baffles. The members direct the path of water downward to promote the settling of solids and the mixing of water in the tank (e.g. prevent short circuiting). Next, there is a settling promoter (e.g. prism shaped baffle) configured to promote current density throughout the tank. The settling promoter is configured to direct the flow of water to the center of the up flow chamber (e.g. in a uniform manner). This baffle design is depicted in greater detail in FIG. 11.

[0232] Referring to FIGS. 9 and 10, each engineered wetland tank contains a different media, where the depth of the media within each wetland is approximately four feet deep. Also, each engineered wetland is configured accept aeration from an aeration system (or portions thereof) which extends beneath (under) the media towards the bottom portion of the engineered wetland. Each wetland includes two types of aeration systems: an aquarium tubing-based aeration system and a diffuser tubing-based aquarium system. Each engineered wetland is designed for 1 day HRT under normal operating conditions.

[0233] Engineered wetland 1A includes plastic media in an elongated ring shape (e.g. BioRings) (SA=32 ft.sup.2/ft.sup.3). Engineered wetland 1A houses the control aquarium tubing aeration system, and ten (10) fine bubble diffusers which are 20 inches long.

[0234] Engineered wetland 2A includes lava rocks (porous rock) as the media, with an average size 1-2. Wetland 2A includes the aquarium tubing aeration system, and eight sections of weighted bubble tubing which are each 69 in length. The aeration tubing includes a fiberglass grating which rests on concrete blocks to prevent the media from causing the aeration tubing.

[0235] Wetland 3A includes ASTM No 3 stone (aggregate) as the media, with an average size of 1-2. Wetland 3A contains the control aquarium tubing aeration system, and eight weighted bubble tubing which are each 69 in length. The aeration tubing includes a stainless steel wire mesh which rests on concrete blocks to prevent the media from causing the aeration tubing.

[0236] In wetland B, each tank in this portion is divided into two sections, and water flows sequentially through each sections. The function of the first section is denitrification (i.e. conversion of nitrate to nitrogen gas by anaerobic and/or anoxic bacteria). The first section includes a carbon source (e.g. molasses, methanol, wood chips) to feed the bacteria. The function of the second chamber is additional aeration and removal of any residual BOD from the carbon source added in the first chamber. The second chamber contains a growth media for bacteria to grow on (e.g. and for plants, cattails to root in) and is aerated (e.g. configured to an aeration device).

[0237] Engineered wetland 1B includes wood chips as the carbon source in section 1 and contains BioRings as the media in section 2. The aeration system in section 2 includes both aquarium tubing, and eight sections of weighted bubble tubing which are each 47 in length.

[0238] Engineered wetland 2B includes rocks as the media in section 1. Prior to entering section 1, the influent will be mixed (e.g. in line) with a water/molasses mixture (e.g. at low concentration) as the carbon source. Engineered wetland 2B includes No 3 stone media in section 2 and the aeration system in section 2 includes both aquarium tubing, and nine weighted bubble tubing sections which are each 47 in length. A stainless steel wire mesh rests on concrete blocks to protect the aeration tubing (e.g. from the weight of the media). Without being bound to particular mechanism or theory, the mixed metal oxide cell (e.g. bauxite residue cell) is believed to function to provide (if needed) final polishing (TSS removal) and disinfection (pathogen removal, e.g. indicated via fecal coliform, e. coli removal) to the wastewater, resulting in cleaned water. The cell will use two separate modules. One module includes bauxite residue (e.g. alkaline clay) as received from the storage facility. The other module includes bauxite residue with 2.5 wt. % ZVI in pelletized form (e.g. pellets).

[0239] The following tables provide data obtained via the pilot system.

TABLE-US-00001 Conventional Baffle Baffle Configuration Min % Avg. % Max % Min % Avg. % Max % removal removal removal removal removal removal Total COD 39 72 94 42 75 96 BOD5 74 86 97 77 88 99 NH3N 33 62 34 75 NO3N 77 95 72 91 PO4 58 65 70 72 TSS 92 97 90 98 VSS 92 97 91 99

TABLE-US-00002 Wetland Influent Min Max Avg. Total 48 395 292 COD Soluble 30 179 90 COD BOD 5 29 759 170 NH3N 13 48 28 values in mg/L

TABLE-US-00003 Wetland 1A Wetland 2A Wetland 3A Min Max Avg Min Max Avg Min Max Avg Total COD 35 92 54 12 58 30 11 70 36 Soluble COD 20 66 39 8 51 24 2 50 25 BOD 5 6 7 6.5 3 3 3 n/a n/a n/a NH3N 2.2 44 15 0.15 25 8.5 0.32 40 17 values in mg/L

[0240] In some embodiments, the hydraulic loading rate of the anaerobic settling/treatment tank is at least about 0.008 gal/min/ft.sup.2 to not greater than about 0.143 gal/min/ft.sup.2.

[0241] In some embodiments, the hydraulic loading rate of the anaerobic tank is: at least 0.01 gal/min/ft.sup.2; at least 0.025 gal/min/ft.sup.2; at least 0.05 gal/min/ft.sup.2; at least 0.075 gal/min/ft.sup.2; at least 0.1 gal/min/ft.sup.2; at least 0.125 gal/min/ft.sup.2; at least about 0.140 gal/min/ft.sup.2.

[0242] In some embodiments, the hydraulic loading rate of the anaerobic tank is: not greater than 0.01 gal/min/ft.sup.2; not greater than 0.025 gal/min/ft.sup.2; not greater than 0.05 gal/min/ft.sup.2; not greater than 0.075 gal/min/ft.sup.2; not greater than 0.1 gal/min/ft.sup.2; not greater than 0.125 gal/min/ft.sup.2; not greater than about 0.140 gal/min/ff.

[0243] In some embodiments, the hydraulic loading rate of the engineered wetland is at least about 0.002 to about 0.072 gal/min/ft.sup.2.

[0244] In some embodiments, the hydraulic loading rate of the wetland is: at least 0.002 gal/min/ft.sup.2; at least 0.005 gal/min/ft; at least 0.01 gal/min/ft.sup.2; at least 0.03 gal/min/f; at least 0.05 gal/min/ft; or at least 0.07 gal/min/ft.sup.2.

[0245] In some embodiments, the hydraulic loading rate of the wetland is: not greater than 0.002 gal/min/ft.sup.2; not greater than 0.005 gal/min/ft.sup.2; not greater than 0.01 gal/min/ft.sup.2; not greater than 0.03 gal/min/ft.sup.2; not greater than 0.05 gal/min/ft; or not greater than 0.07 gal/min/ft.sup.2.

[0246] In some embodiments, the hydraulic loading rate of the mixed metal oxide media cell is at least about 0.011 gal.Math.min/ft.sup.2 to not greater than about 0.444 gal/min/ft.sup.2.

[0247] In some embodiments, the hydraulic loading rate of the BR cell is: at least 0.05 gal/min/ft; at least 0.1 gal/min/ft; at least 0.2 gal/min/ft.sup.2; at least 0.3 gal/min/ft.sup.2; or at least 0.4 gal/min/ft.sup.2.

[0248] In some embodiments, the hydraulic loading rate of the BR cell is: not greater than 0.05 gal/min/ft.sup.2; not greater than 0.1 gal/min/ft.sup.2; not greater than 0.2 gal/min/ft.sup.2; not greater than 0.3 gal/min/ft.sup.2; or not greater than 0.4 gal/min/ft.sup.2.

[0249] In some embodiments, the flow rate of water into the system is at least about 1 gpm to about 10 gpm. In some embodiments, the flow rate of water into the system is: at least 2 gpm; at least 4 gpm; at least 6 gpm; or at least 8 gpm. In some embodiments, the flow rate of wastewater into the system is not greater than 2 gpm; not greater than 4 gpm; not greater than 6 gpm; or not greater than 8 gpm.

[0250] In some embodiments, the hydraulic conductivity of the mixed metal oxide cell is at least about 0.0009 cm/s to not greater than about 0.19 cm/s.

[0251] In some embodiments, the hydraulic conductivity of the pelletized media in the mixed metal oxide cell is: at least about 10.sup.1 cm/s to about 10.sup.4 cm/s.

[0252] In some embodiments, the porosity of the engineered wetland is at least about 35% (e.g. aggregate) to not greater than about 95% (e.g. plastic media or hollow cylindrical form).

[0253] In some embodiments, the field capacity of the mixed metal oxide media cell is at least about 50% to not greater than about 60%.

[0254] In some embodiments, the anaerobic settling/treatment tank is configured to remove at least about 50% to not greater than about 99% of BOD/COD from a wastewater stream.

[0255] In some embodiments, the engineered wetland is configured to remove at least about 40% to not greater than about 99.9% of pathogens (e.g. indicated by fecal coliform).

[0256] In some embodiments, the mixed metal oxide medial bed is configured to remove at least about 60% to not greater than about 100% (e.g. below detection limit) of pathogens (e.g. indicated by fecal coliform).

[0257] In some embodiments, the mixed metal oxide media bed is configured to remove at least about 30% to not greater than about 99% of pharmaceuticals and personal care products.

Example 2

Column Study

[0258] A pilot was run to test bauxite residue and ZVI media disinfection. Five columns were constructed, and each was 30-inches tall with a 4-inch diameter. The column influent water was pumped from a front portion of an existing wastewater treatment system (wastewater had solids removed via a septic system, but had otherwise undergone limited, if any, treatment).

[0259] Each column contained a different media, including: sand (control), BR only, BR with 2.5 wt % ZVI; two columns, BR with 2.5 wt % ZVI and sand with 2.5 wt %/ZVI, each had a compost pretreatment column to remove dissolved oxygen from the influent water. Without being bound to a particular mechanism of theory, it is believed that by adding a small amount of ZVI to the BR media, wastewater disinfection would be enhanced without reducing the hydraulic conductivity of the column (e.g. due to accumulation of iron oxides in the filter bed).

[0260] The columns were constructed to operate in up-flow mode. Each column contained 6.35 cm (2.5 inches) of gravel on the bottom to ensure the influent water dispersed evenly throughout the column. After the gravel was placed, 76.2 cm (30 inches) of media was put into the column. The top of the column was connected to a smaller column, where the pH, dissolved oxygen, and temperature were measured with a Fischer Scientific Accument AP63 pH Probe, and a Hach HQ40d Dual-Input Multi-Parameter Digital Meter LD0101 Dissolved Oxygen/Temperature Probe. The columns were run for a 151 day period from spring through fall in an outdoor setting.

[0261] In the pilot-scale BR and ZVI disinfection columns, the BR and ZVI columns removed pathogens (e.g. indicated via fecal coliform) more effectively than the control (sand) column. The data showed that the column containing 2.5 wt %/ZVI performed better than the BR only column, but analysis of the data showed no statistically significant difference was achieved by adding the ZVI. Without being bound to a particular mechanism or theory, since it consistently outperformed sand, BR's mechanism of action is thought to be a combination of filtration and another mechanism;

[0262] The five (5) disinfection media scenarios run in seven (7) columns are illustrated in FIG. 12A. The first column was a control, containing only sand. The second column contained BR only. The third scenario consisted of a pretreatment column containing spent mushroom compost with 2.5 wt % ZVI, followed by a column containing sand with 2.5 wt % ZVI (i.e. this scenario had two columns in series). The fourth column contained bauxite residue with 2.5 wt % ZVI. The fifth scenario consisted of a pretreatment column containing spent mushroom compost with 2.5 wt % ZVI followed by a column containing bauxite residue with 2.5% ZVI (i.e. this scenario had two columns in series). The bauxite residue was taken from a Residue Storage Area in Texas, USA.

[0263] The flow rate to all of the columns was 10 mL/min, with an empty bed contact time of 624 minutes; the flow rate to the columns was increased to 20 mL/min towards the end of the test, as indicated in FIG. 13. After the increase in flow rate, the empty bed contact time was reduced to about 300 minutes. The hydraulic residence time varied with the porosity of the various media, and ranged from 3.8 hours for column 5b with bauxite residue and ZVI, to 5.1 hours for columns 3a and 5a with spent mushroom compost and ZVI, as shown in FIG. 12B.

[0264] Fecal coliform (FC) concentration was the focus of the data analysis for the pilot columns. Other parameters, including dissolved oxygen, oxidation reduction potential, chemical oxygen demand, total organic carbon, nitrate, ammonia, and phosphate were also monitored; however, FC concentration showed no correlation with any of these data. Concentration of dissolved ferric and ferrous iron in column effluents were also analyzed; however, most results were below method detection limit.

[0265] The effluent from each column was generally sampled twice/week for three months. The table below summarizes the analytical methods used for analyzing the samples during this period. Prior to day 50, only one influent sample was taken, generally at column 4 (BR+ZVI), and it was assumed that other influents were the same since they were taken from the same source; however, the influent FC concentrations for each column were starting on day 50, individual fecal coliform samples were taken at the influent to each column. For the next two and a half months, columns were sampled once per week for influent and effluent FC concentration.

TABLE-US-00004 Pilot Study Parameters Measured and Analytical Methods Used Parameter Analytical Method or Instrument Used Pressure Pressure Gage (Inches of Water) pH Fischer Scientific Accument AP63 pH Probe Dissolved Hach HQ40d Dual-Input Multi-Parameter Digital Meter Oxygen LD0101 Dissolved Oxygen/Temperature Probe Temperature Hach HQ40d Dual-Input Multi-Parameter Digital Meter LD0101 Dissolved Oxygen/Temperature Probe Chemical Method 8000 Reactor Digestion Method Oxygen Demand Nitrate EPA 300.0 (1.sup.st two weeks of pilot operation) Cadminum Reduction Method (after 1.sup.st two weeks of pilot operation) Ortho- EPA 300.0 (1.sup.st two weeks of pilot operation) Phosphate PhosVer3 (Ascorbic Acid) Method (after 1.sup.st two weeks of pilot operation) Ammonia 4500 NH3NC 20th Edition (1.sup.st two weeks of pilot operation) Salicylate Method (after 1.sup.st two weeks of pilot operation) ICP Metals Inductively Coupled Plasma Scan Fecal Coliform Standard Method 9222D Membrane Filtration Total Iron EPA Method 6010B Ferric Iron Standard Method 3500-Fe B (Phenanthroline Method) Ferrous Iron Standard Method 3500-Fe B (Phenanthroline Method) Dissolved Iron Inductively Coupled Plasma Total Organic USEPA SW-846 III Ed., Method 9060 Carbon

[0266] FIG. 13 below shows the effluent FC concentrations for each column versus time through the course of the study. During the first 6 weeks of monitoring, an effluent sample was taken at each column, but only one sample was taken at the influent and assumed to be the same for all columns. After week 4, samples were taken at the influent and effluent of each column, and it was discovered that FC concentration varied between the columns. Because influent concentrations for each column were not sampled for the duration of the experiment, effluent FC concentration was the focus of the data analysis, though average percent removal was examined. Average FC influent concentration was approximately 5000 CFU/100 mL. The sand control column exhibited a lag in performance, as indicated in FIG. 13; the remaining columns performed more consistently over the course of the pilot. When the flow rate was doubled (as indicated by the dashed vertical line on the graph), FC effluent concentration tended to increase slightly, as empty bed contact time was reduced from about 600 minutes to about 300 minutes per column.

[0267] The right-most bars in FIG. 14 below shows each column's effluent concentration, averaged over the course of the pilot study. The columns with a compost pretreatment step consisting of two columns in series were considered a single entity, with the influent as the influent to the A compost column, and the effluent as the effluent from the B sand, BR, or ZVI media column. The method detection limit for FC concentration was 10 CFU/100 mL, and results below the detection limit were reported as <10; in the following analysis, any values reported <10 were assumed to be 5 CFU/100 mL.

[0268] Looking at all the data, the control sand column had the highest average FC effluent; this high concentration may be because the sand column exhibited a lag in performance for several weeks as indicated in FIG. 13. The columns with compost pretreatment performed slightly better than the single columns, most likely because they had a hydraulic residence time approximately double that of the single columns. Much of the data for the columns with compost pretreatment was below detection limit.

[0269] The BR+2.5% ZVI column had lower effluent concentration than the BR only column, and the BR+2.5% ZVI column with compost pretreatment had lower effluent concentration than the sand+2.5% ZVI with compost pretreatment column; these results indicate not only that BR improves disinfection compared to sand, but also that the addition of ZVI seems to enhance BR disinfection.

[0270] Referring to FIG. 14, the graph depicts the average pathogen effluent concentration (indicated by fecal coliform, where the influent average is 5030 CFU/100 mL).

[0271] The centered bars for each column in FIG. 14 show the average FC effluent concentration with data from the sand column startup period and the 20 mL/min flowrate period removed. Data from the first 30 days of monitoring (typical sand filter startup period) and the last 42 days of monitoring were removed from the set. Even accounting for the sand column startup period, all columns showed lower average effluent FC concentration

[0272] The right-most bars in FIG. 14 show the average effluent FC concentration with only data from the last 42 days of monitoring, the 20 mL/min period, removed. The center columns show that the columns containing sand were affected by the startup period, having effluent concentration higher than the red bars. The columns not containing sand performed about the same when data from the startup period was and was not included. The BR+2.5% ZVI column with compost pretreatment did not seem to follow this trend; however, most data points were at or below detection limit except for one high value that may have skewed the results.

[0273] FIG. 15 is a graph depicting the average percent removal of pathogens (e.g. indicated as fecal coliform) for the five different columns tested. For this data, influent and effluent FC concentrations were measured at each column and data from the first 6 weeks of monitoring was removed. Percent FC removal is measured as (CFU inf-CFU eff)/CFU inf. Outliers or unreliable data were considered any data points below two standard deviations below the mean and any data points below zero (indicating that the effluent FC concentration was higher than the influent). Data reported below the detection limit (<10 CFU/100 mL) were assumed to be 5, so average percentages did not skew high or low.

[0274] Like the average effluent concentration, the average percent removal shows that all treatment columns performed better than sand, and that the columns with the compost pretreatment step performed better than the columns without the additional residence time. The column with BR+2.5% ZVI performed slightly better than the BR only column, and the BR+2.5% ZVI column with compost pretreatment performed better than all other treatment columns.

[0275] Because it was believed that due to experimental error, reliable data for the influent concentration was not available for a large portion of the study, effluent FC concentration only was considered in the statistical analysis. In the BR/ZVI column tests, all treatment columns performed statistically significantly better than sand at a 90% confidence level; even after the startup period during which the sand column developed its biological disinfection layer, all treatment columns performed statistically significantly better than sand at an 86% confidence level.

[0276] Without being bound to a particular mechanism or theory, filtration is still believed to play a role in disinfection in the bauxite residue cell. The data in the column experiments showed that BR removes FC more effectively than the simple granular filtration mechanism seen in sand. These results indicate that another mechanism in addition to granular filtration is at work in disinfection by BR.

Example 3

Media Pelletizing Experiments

[0277] In order to pelletize the BR with 2.5 wt. % ZVI, the BR was first dried to remove the excess moisture content of the BR (e.g. 25-30% moisture content in as-received form). Once dried, the BR and ZVI were both ground into a powder (e.g. fine powder), completed via a cone mill (e.g. which ground and mixed the components). Once the media were ground and commingled, water was added to the mixture (e.g. to act as a binding agent). The media with binding agent was mixed in a Simpson mixer until the media formed into balls/pellets. The pelletized media was allowed to air dry. The average size of the pellets varied. D.sub.25 was . D.sub.50 for the pelletized BR/ZVI material was 0.187 in (standard US mesh size 4).

[0278] In some embodiments, the pelletized media (BR and ZVI) is from about 1/20 of an inch to about 3 inches.

Example 4

Pelletized Vs. Non-Pelletized Media

[0279] Column experiments were carried out to compare pathogen removal (e.g. indicated via fecal coliform removal) of pelletized and unprocessed (non-pelletized) BR. Three columns were tested, and contained the following media: pelletized BR with 2.5 wt % ZVI, BR hand mixed with 2.5 wt % ZVI, and BR only. Each column had an HRT of 4 hours. The columns drew influent with an average fecal coliform concentration of 143 CFU/100 mL. The pelletized BR with 2.5 wt % ZVI began running 37 days before the BR only column began running and 101 days before the hand-mixed BR with 2.5 wt % ZVI; samples were collected from each column approximately weekly.

[0280] Influent and effluent samples were analyzed for fecal coliform concentration using Standard Method 9222D; samples were analyzed by Microbac, a certified outside lab. Data was analyzed for percent removal, C.sub.infC.sub.eff/C.sub.inf. This data set included 9 or fewer samples per column. Results indicate that the pelletized BR with 2.5 wt % ZVI works about as well as the unprocessed (non-pelletized) BR.

Example 5

Computational Flow Dynamics Modeling

[0281] Computational fluid dynamics (CFD) modeling of various baffle configurations was completed to understand the velocity profile of different configurations. Modeling was done on Ansys Fluent Software Version 13.0. Each model run assumed influent flow of 1 gallon per minute (gpm) plain water into one chamber plus half of another chamber, where the chamber is depicted as two-dimensional chambers (consisting of a 60 water depth, 6 wide downflow section, and 24 wide up flow section, and the 6 wide down flow section of the subsequent chamber). Each chamber includes: one down flow section (before hockey stick shaped baffle to direct flow of water down) and one up flow section (after hockey stick or suspended baffle to direct the flow of water up).

[0282] Referring to FIG. 18, the resulting models depicts a two-dimensional velocity vector profile between the baffles in the system, where the velocity profile is indicative of the water velocity through the chamber and displays dead zones, or areas of slow velocity/no mixing, if any.

[0283] Referring to FIG. 18, the model on the left was of the baffle configuration depicted in FIG. 11 (e.g. hockey stick-shaped baffle and the three spaced members (e.g. vane baffles)), while the model on the right was of the conventional baffle design. The dead zones perceived through visual observation of the resulting CFD models are circled in each model in FIG. 18. In contrast with the conventional baffle configuration, the baffle configuration of the instant disclosure as a much smaller dead zone area. Without being bound by a particular mechanism or theory, it is believed that this may attribute to a higher degree of mixing, improved treatment as compared to the conventional system (e.g. promote solids retention, removal of inorganic solids, organic solids).

[0284] While various embodiments of the present invention have been described in detail, it is apparent that modifications and adaptations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention.