WO2019195543A1

WO2019195543A1 - Contaminant removal system

Info

Publication number: WO2019195543A1
Application number: PCT/US2019/025774
Authority: WO
Inventors: Mark KROPILAK; Gerard Hodge
Original assignee: Kropilak Mark; Gerard Hodge
Priority date: 2018-04-04
Filing date: 2019-04-04
Publication date: 2019-10-10

Abstract

A media for removing contaminants from an aqueous stream including a bed of foam pieces. The foam pieces are made up of a foam substrate, an adherent coating on a surface of the foam substrate, and a chemically reactive substance and/or an adsorbent adhered to the adherent coating. A system for removing contaminants from a liquid stream includes a vessel with one or more inflow pipes configured to direct the liquid stream to a location in the vessel proximate to a first end of the vessel and one or more effluent pipes connected to one or more portholes located proximate a second end of the vessel. The system also includes the media described above located in the vessel. The system is configured such that the liquid stream flows into the media, out the one or more portholes such that contaminants are removed from the liquid stream by the media.

Description

CONTAMINANT REMOVAL SYSTEM

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application no. 62/652,695, filed April 4, 2018, the entire disclosure of which is hereby incorporated by reference as if set forth fully herein.

FIELD OF THE INVENTION

The present invention relates to the removal of contaminants from a liquid or aqueous stream using a suspended bed reactor comprised of media using foam-based chemistry, arranged in various system configurations.

BACKGROUND

There are several contaminants in aqueous streams that are of considerable concern due to their effects on wildlife as well as humans. These contaminants can include, but are not limited to:

• Selenium

• Chromates

• Cadmium

• Arsenic

• Cobalt

• Nickel

• Antimony

• Mercury

• Titanium

• Uranium

All of these contaminants can be removed or neutralized by reaction with certain adsorbents such as, but not limited to, activated carbon, diatomaceous earth, alumina, zero valent iron (Fe°, or ZVI) or other suitable adsorbents. Each of these has demonstrated ability to reduce or absorb contaminants. U.S. Patent No. 8,668,831 discloses a permeable reactive barrier and a method of removing these contaminants from water. The structure includes a reticulated foam substrate with high permeability, an adherent coating and an adsorbent arranged in a reticulated foam structure. The disclosure of this patent is hereby incorporated by reference in its entirety herein.

Unfortunately, media is often used in large formats to remove contaminants from large quantities of water at high flow rates. Typical uses of such media is as a large solid block of media within a reactor or vessel. In such uses, channeling (rat holing or bypassing) occurs, which reduces the effectiveness of the media for contaminant removal. What is needed is a form of media and a system of using that media that provides improved results at removing contaminants from liquids, typically aqueous solutions, a modular vessel design that is scalable and allows the media to interact with the liquid in a contained, reducing environment while maximizing the availability of the chemically reactive

substances/adsorbents on the media, and a system design to connect multiple reactor vessels to scale up or down to treat different flow rates.

SUMMARY OF THE INVENTION

In a first aspect, the present invention relates to a media for removing contaminants from an aqueous stream. The media may include a bed of foam pieces made up of a foam substrate an adherent coating on a surface of the foam substrate; and a chemically reactive substance and/or an adsorbent adhered to the adherent coating.

In the foregoing embodiment, the foam pieces may have dimensions between ¼ inch and 3 inches per side. In each of the foregoing embodiments, the foam pieces may have a cuboid shape. In each of the foregoing embodiments, the foam pieces may have dimensions of ½ inch by ½ inch by ½ inch to 1 inch by 1 inch by 1 inch. In each of the foregoing embodiments, the foam pieces may have an irregular shape.

In each of the foregoing embodiments, the chemically reactive substance and/or the adsorbent may be selected from the group consisting of bleach, powdered zerovalent iron, copper, zinc, reducing agents, oxidizing agents, acids, bases, activated carbon, carbon, alumina, diatomaceous earth, zeolites, and any combination thereof. In each of the foregoing embodiments, chemically reactive substance and/or the adsorbent is powdered zerovalent iron. In each of the foregoing embodiments, the media may be made up of 70 wt.% to 85 wt.% chemically reactive substance and reactive adsorbent, 5 wt.% to 10 wt.% adhesive and 10 wt.% to 25 wt.% foam.

In each of the foregoing embodiments, the foam may reticulated foam. In each of the foregoing embodiments, the chemically reactive substance and/or the adsorbent may a reactive adsorbent.

In each of the foregoing embodiments, the foam may have a porosity of at least 80% up to 98%, or 85-98%, or 90-98% or 95-98%.

In each of the foregoing embodiments, the chemically reactive substance and/or adsorbent are suitable for removal of a contaminant selected from the group consisting of selenium, chromates, cadmium, arsenic, cobalt, nickel, antimony, mercury, titanium, uranium and any combination thereof, or the chemically reactive substance and/or adsorbent are suitable for removal of any one of the foregoing contaminants or any one particular combination of the foregoing contaminants.

In each of the foregoing embodiments, the foam pieces may have any one of 4-60, 4- 30, 6-20 or 8-12 pores per linear inch, as measured by ASTM D3574-17, Standard Test Methods for Flexible Cellular Materials— Slab, Bonded, and Molded Urethane Foams,

ASTM International, West Conshohocken, PA, 2017.

In each of the foregoing embodiments, the pores may have any one of an average diameter of from 0.05 to 0.2 or 0.06 to 0.15 or 0.08 to 0.11 inches.

In each of the foregoing embodiments, the media may be granulated and pourable.

In another embodiment is provided a system for removing contaminants from a liquid stream. The system may include a vessel with one or more inflow pipes configured to direct the liquid stream to a location in the vessel proximate to a first end of the vessel, one or more effluent pipes connected to one or more portholes located proximate a second end of the vessel; and a media of any of the foregoing embodiments located within the vessel between the one or more inflow pipes and the one or more portholes so as to ensure that flow of the liquid stream passes through the media for removing contaminants from the liquid stream. The system is configured such that the liquid stream flows in the one or more inflow pipes and into the media, out the one or more portholes, and through the one or more effluent pipes, and one or more contaminants are removed from the liquid stream by the media during contact with the media. In each of the foregoing embodiments of the system, the system may also include a diffuser connected to the one or more inflow pipes, said diffuser configured to distribute flow of the liquid stream over a cross-sectional area of the vessel.

In each of the foregoing embodiments of the system, the one or more inflow pipes may be located proximate to a bottom of the vessel and the portholes may be located proximate to a top of the vessel, both determined when the vessel is upright.

In each of the foregoing embodiments of the system, the vessel may have a capacity of 40-400 gallons and/or the system may be a modular, stand-alone unit. In each of the foregoing embodiments of the system, the system may have no moving parts within the vessel.

In each of the foregoing embodiments of the system, the vessel may be a first vessel and the system may further include a second vessel having one or more inflow pipes connected with the one or more effluent pipes of the first vessel.

In each of the foregoing embodiments of the system, the system may be an upflow system. In each of the foregoing embodiments of the system, the system may be a downflow system.

In each of the foregoing embodiments of the system, the system may have vessel sizes and configurations as listed in the table below.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a single piece of media material according to an embodiment of the invention. Fig. 2 shows a plurality of the pieces of media material shown in figure 1 forming media.

Fig. 3 is a diagram of a reaction vessel used in an up-flow treatment system according to an embodiment of the invention.

Fig. 4 is an internal view of the reaction vessel of Fig. 3.

Fig. 5 is an internal view of a reaction vessel used in a down-flow treatment system according to an embodiment of the invention. Fig. 6 is a front view of an up-flow treatment system organized in series according to an embodiment of the invention.

Fig. 7 is a close-up view of three reaction vessels shown in Fig. 6.

Fig. 8 is a rear view of the treatment system shown in Fig. 6.

Fig. 9 is a close-up rear view of three reaction vessels shown in Fig. 8.

Fig. 10 is a schematic flow diagram of an up-flow treatment system organized in series.

Fig. 11 is a front view of a down-flow treatment system organized in parallel according to an embodiment of the invention.

Fig. 12 is a close-up view of three reaction vessels as shown in Fig. 11.

Fig. 13 is a rear view of the treatment system shown in Fig. 11.

Fig. 14 is a close-up rear view of three reaction vessels as shown in Fig. 13.

DFTATFFn DESCRIPTION OF THE INVENTION

The present media, containment vessel and system is an improvement in the realm of foam-based chemistry. The purpose is to place media in a liquid or to have an aqueous stream pass through media configured as a suspended bed in reactor vessels or tanks, for the removal of dissolved metals or other contaminants from the liquid or aqueous stream.

Media Size, Composition and Manufacturing:

The present invention includes a media 101 made of foam pieces 100 which may be reticulated foam pieces 100, in the shape of cubes or cuboids or other similar shapes.

Although a cube, or cuboidal shape is preferred, it is understood that another shape may also be used, such as a sphere, cylinder, peanut, pyramid, etc. Additionally, it is also understood that the shape can be irregular, for example a shredded piece of foam, or an irregular globule. Figure 1 shows a single piece 100 of media material having the preferred cuboid shape. Figure 2 shows a plurality of pieces 100 of media material which together make up a media 101.

The foam pieces may have a porosity or void volume of 80-98%, or 85-98%, or 90- 98% or 95-98%. Typically, the foam pieces will have 4-60, 4-30, 6-20 or 8-12 pores per linear inch, as measured by ASTM D3574-17, Standard Test Methods for Flexible Cellular Materials— Slab, Bonded, and Molded Urethane Foams, ASTM International, West

Conshohocken, PA, 2017. 9-10 pores per linear inch corresponds to about 85 pores per square inch. The pores may have an average diameter of from 0.05 to 0.2 or 0.06 to 0.15 or 0.08 to 0.11 inches. Reticulated foam is a very porous, low density solid foam. Preferably, the pieces 100 have a dimension that is greater than ¼ inch in all directions. More preferably, each dimension of the pieces can be various sizes between ¼ inch and 3 inches per dimension, and most preferably the pieces are in the form of a cube shaped foam piece having dimensions of ½ inch by ½ inch by ½ inch to 1 inch by 1 inch by 1 inch, wherein each of these three dimensions can be independently varied with the range, for example, it could be 3/4 inch by 3/4 inch by 1/2 inch.

It is understood that the pieces 100 utilized in the media 101 and system may be uniform in size, or may have various different sizes. Preferably, the pieces are substantially uniform in size and the same size pieces are preferably capable of being used for multiple different applications so that multiple designs are not necessary and manufacturing can be simplified. However, it is understood that different designs may be used for different applications for optimization purposes. The size and shape of the media may be chosen to obtain a preferred fill rate of the vessel, and/or to prevent water from bypassing the media or rat hole through the media bed. The optimized media 101 creates a bed that may be agitated using reverse flow to ensure voids are filled and gaps close off.

The foam pieces 100 may be made from a material as disclosed is U.S. Patent No. 8,668,831. Specifically, the media 101 contains reticulated foam pieces 100 having an optional adherent coating added to their surface, and a chemically reactive substance and/or adsorbent added to the media or the adherent coating. The chemically reactive substance may be any suitable chemically reactive substance for a chemical reaction with the contaminant of interest such as an acid-base reaction, a reduction reaction and an oxidation reaction, for example. Suitable chemically reactive substances include, for example, bleach, iron such as powdered zerovalent iron (ZVI), copper, zinc, reducing agents, oxidizing agents, acids and bases.

The adsorbent may be any suitable absorbent for adsorbing the contaminant from a liquid stream. Particularly preferred adsorbents are reactive adsorbents. The adsorbents may be selected from the group consisting of activated carbon, carbon, alumina, diatomaceous earth, zeolites, and any combinations thereof, or any other similar adsorbents.

Preferably, the media is granular and pourable. Such media configurations may be easily transported via bulk haulage or large volume“super sacks,” and from there can be readily loaded or poured into tanks or other vessels, and removed by vacuum or other mechanical or manual process, such as tipping and pouring the media from the vessel when the media is exhausted or the project ends. The preferable cuboid shape is preferably sized to be granular and pourable for this purpose. Manufacturing

There are two preferred methods of manufacturing the media. The first

involves cutting foam to appropriate sizes, applying adhesive or adherent and then adding adsorbent/chemically reactive substance particles to the adherent. The second involves treating the foam with adhesive and adding adsorbent/chemically reactive substance prior to cutting the foam.

In a preferred method of manufacturing the foam, the manufacturing involves cutting foam, applying adhesive or adherent and then adding ZVI or other adsorbent particles to the adherent. The use of this preferred method of manufacturing allows for more precise control of chemically reactive substance/adsorbent impregnation into the media when compared to impregnating the foam prior to cutting. Specifically, the impregnation can be more tightly controlled based on the increased amount of surface area of the media, which allows for designing the size quantity and density of the applied chemically reactive

substance/ ads orbents .

The weight of the volume of media that would occupy a gallon is selected based upon process application and manufacturing method and may be optimized to suit the pollutants and concentrations being addressed. The finished media will have a per gallon weight of between 2 and 7 pounds. With the overall weight of the media representing 100 wt.%, the media preferably includes:

70 wt.% to 85 wt.% adsorbent grit,

5 wt.% to 10 wt.% adhesive and

10 wt.% to 25 wt.% foam.

Media Application as a Suspended Bed:

When placed in a vessel, this new media configuration provides better fill rates for loading the media into the vessel and provides a consistent depth of material for the water or liquid to pass through. The opportunity for gaps in the media bed to exist (leading to rat holing or bypass) is thereby minimized providing a better solution than a traditional Packed Bed Reactor. In a traditional packed bed, the chemically reactive substance/adsorbent itself is packed into a column and the water is pushed through the chemically reactive

substance/adsorbent. This can lead to bubbles and holes in the chemically reactive substance/adsorbent bed and high pressure requirements. In the present invention, the pieces of foam media are packed into a vessel, since the chemically reactive substance/adsorbent is bound to the foam, it is“suspended” by the foam and is immobile. The suspended bed of chemically reactive substance/adsorbent formed by the packed bed of foam of the present invention is sufficiently permeable so that liquid can flow through with relatively low pressure requirements.

The porosity of the foam ensures a relatively low pressure drop through the treatment bed. The low pressure drop and high porosity also allows for a more flexible arrangement and a lower system operating pressure than would be the case for a typical packed bed reactor.

The consistent application of chemically reactive substances/adsorbents to the media coupled with controlled flow rates ensures very high contact ratios between the liquid to be treated and the adsorbent/chemically reactive substance, providing a better option than traditional Fluidized Bed reactors which typically require use of significantly less chemically reactive substance/adsorbent per unit volume. For example, the high contact rate lowers the effective time to treat the pollutants and allows for a smaller volume when compared to typical fluidized bed reactors. Since the adsorbent/chemically reactive substance is bound to the web of the foam, the adsorbent/chemically reactive substance is effectively“suspended” throughout the depth of the treatment vessel. This approach is therefore termed a“Suspended Bed Reactor”.

The amount of chemically reactive substance/adsorbent bound to a piece of foam media of a defined volume can be tailored to provide the ability to increase the amount of chemically reactive substance/adsorbent per gallon of volume in the reactor vessel. Since the chemically reactive substance/adsorbent is“bound” in place to the media this provides better control of how much water flows around each piece of media. A fluidized bed involves a volume of the chemically reactive

substance/adsorbent in a much larger vessel and the mixture is agitated by paddle wheels, compressed gases, liquids, etc. to improve the contact between each particle of polluted water and the chemically reactive substance/adsorbent. The system sizing and design is based on mixing theory and probability rates for contact. It is typically a large volume since the contact rates cannot be guaranteed since such systems require relatively large amounts of fluidizing material.

Experimental Data:

Testing has been done on the media on an experimental basis in the laboratory or at a power plant or at a manufacturing facility. The generated data shows or

supports the ability of the new media configuration to remove dissolved metals like chromium, and contaminants like selenium, and cyanide with improved results

compared to alternative treatments. The same weight of media has been shown to be more effective when tested in the shape of cubes or cuboids rather than in dense

blocks of media, presumably due to more completely filling the treatment vessel,

thereby providing a greater volume of adsorbent/chemically reactive substance,

eliminating bypass around the media and hence improving the contact time between the adsorbent/chemically reactive substance and the liquid to be treated and lowering the overall treatment time.

The media has also been shown to have improved flow at lower system pressure drop. Without being bound by theory, the flow through the bed of cubes or cuboids seems to create a type of meandering, serpentine flow through and around the cuboid media that minimizes channeling (rat holing or bypassing) that can occur with large solid blocks of media. In the event that the media becomes blinded or plugged up with influents or precipitated solids, this media configuration may be agitated via reverse flow to dislodge the solids.

Table 1: Test Results: Field and Lab

Application of Media as a System for Treating an Aqueous Stream:

Another aspect of the present invention is a system for treating an aqueous stream using the media described herein. The system is described in terms of the containment vessel and the system configuration.

Containment Vessel:

The system includes a tank or vessel with at least one inflow pipe and one or more effluent pipes that can be used to run a liquid or aqueous stream through the vessel, where the vessel is loaded with shaped media as described herein that works as a Suspended Bed Reactor.

The reactor vessels are modular in design and are sized for a predetermined flow rate and pollutant to be treated. The size of the vessels may be increased or decreased as required by the volume of liquid being treated, the retention time required and the configuration of the treatment system (i.e. in parallel or series). These modules are sized in order to be transported using a commercial, over the road trailer and may be lifted into place using conventional lifting means such as a mobile crane or forklift. These modules may site on a concrete slab, or on a level, gravel lined lot and require minimal site preparation. The modules are designed to be located out of doors and do not require further cover or enclosures. The chemical process that occurs inside of the module will occur across all operating temperatures and will not suffer from a lack of efficiency at low operating temperatures.

The flow of water through the vessels shall be either“upflow” or“downflow” depending on the pollutant to be treated and/or the level of precipitate being generated. For low precipitate processes, or processes where the pollutant is“bound” to the chemically reactive substance/adsorbent in the media, an upflow process may be utilized. For higher precipitate processes, the reactor vessel may incorporate a downflow configuration. Prior to being processed by the system, the liquid may be processed using an optional UV light and/or filter.

Fig. 3 shows a diagram of a preferred embodiment of a reactor vessel 210 for an upflow design. In the preferred upflow design for treatment of an aqueous stream, the inflow of water is controlled using a gravity system, or pumped to a hose or pipe that directs water to the bottom of the vessel where a header or distribution system is located. The liquid travels through the media 101 and exits though the top of the vessel. Fig. 4 shows the inside of a reactor vessel 210 for use in the upflow design. The aqueous stream may be transported to the bottom of the vessel through an inlet pipe 222 that may contain a distribution header 244 such as a diffuser plate or pipe grid to decentralize the flow for its continued journey up through the media bed in the vessel 210. The distribution holes in the header, plate, or pipe grid may be oriented in such a way to ensure that no plugging occurs during operation. From the bottom of the vessel, the water will rise as a result of hydraulic pressure via the one or more inflow pipes, pass through the media and then exit from one or more porthole(s) near the top of the vessel or through the lid of the vessel.

Alternately, in a downflow design, the flow, facilitated via gravity or pump, may proceed down through the media bed in the vessel and discharge out of the bottom. The media bed may be supported on a rigid screen at the bottom of the vessel. The liquid flows down through the media and out through the discharge. The flow rate of the liquid through the vessel and the retention time are controlled by flow control valves at the inlet and discharge of the vessel. Provisions are also made to use reverse flow to break up precipitate that may become lodged in the media 101 or between media pieces and allow this material to be flushed out of the system.

Fig. 5 shows an internal view of a reaction vessel used in a down-flow treatment system according to an embodiment of the invention. As shown in the diagram, a purge header 350 may be used to agitate the media. A reverse flow pressurization system may be installed at the base of the media bed (on top of the rigid screen). This system may be used to agitate or“burp” the media bed and free up any precipitate that has formed in and around the media pieces. This latter approach facilitates the removal of precipitated materials that may otherwise accumulate in the vessel. Additional features of the design include provisions to prevent internal pipes from plugging due to precipitated pollutants, or dislodged

adsorbent/chemically reactive substance.

A differentiating point for the vessels for use with either the upflow or downflow configurations is that there are no moving parts within the vessel or tank. This minimizes or eliminates obstructions, wear and tear, maintenance and power or compressed air required for such moving parts in other systems. The tanks may be fed via hydraulic pump or by gravity making them suitable for rural, rustic, remote or undeveloped areas where water quality needs to be improved, but where there may be limited or unreliable electric and utility service. System Configuration and Vessel Sizing:

The size of the tank or vessel will depend on the pollutant to be treated, the flow rate of the water and the desired retention time in each vessel. Individual vessels may be employed for low flow rates of contaminated water like landfill or slag pile leachate or discharge from tannery operation. The system can work based on gravity flow and is applicable to rural, rustic, undeveloped areas where water quality needs to be improved, but where there may be limited or unreliable electric service. Different pollutants may be addressed through the use of media 101 with different adsorbents/chemically reactive substances, each designed to address a particular pollutant or range of pollutants which may be combined into each reactor vessel. Such a mixture may provide flexibility in treating multiple pollutants in each vessel.

Alternately, the vessels may be linked together in series or in parallel depending on the flow rates and the levels of pollutants to be removed. This offers a modular approach to contaminant treatment and provides flexibility for changes at a site should operating conditions change. This can include adding or removing containment vessels or relocating vessels to different locations. Modules designed to treat different pollutants may be combined into common treatment trains to address multipollutant flows, or the media 101, which is manufactured to address individual pollutants, may be blended inside of the modules themselves.

Potential vessel sizes and configurations are listed in the table below.

A single tank or vessel, also known as a treatment pod can be used to treat a stream of water or can be assembled in series to be used as part of a system of several pods. The pod preferably has a tank or vessel with a capacity of between 40 and 400 gallons. The system may also be a modular, stand-alone unit that preferably holds about 100 gallons of media/600 pounds of media. If modular, the system may be built on a movable surface, for example a pallet, so that the system can be moved to different locations. In a preferred embodiment, a 110 gallon drum is used having about 600 pounds. The dimensions for the 110 gallon drum are approximately 3l"O.D. x 43.5"H. For certain uses it may also be preferable to use an 85 gallon drum, which holds approximately 400 pounds of media.

Upflow/series System Configuration

A preferred embodiment of the present invention is a treatment system in an upflow configuration for the treatment of about 25 gallons of liquid per minute. Such a treatment system 200 is shown in Figs. 6-8. There are four reactor vessels 210 arranged in series. One vessel 210 may be installed as a spare reactor. Each vessel 210 is sized for approximately a one-hour retention time, which correlates to approximately 1,500 gallons. The base dimensions for each vessel in this system are 7 ft. wide, 7 ft. deep, 6 ft. high. The vessel is sized so that it can be transported on a standard trailer. For this system, 8 ft. diameter and 6 ft. high cylindrical vessels would produce similar results. The system is also configured so that all valves are accessible from grade level, and such that each vessel can be isolated and bypassed individually.

Specifically, the liquid to be treated is pumped into the system through an inlet header 212. Prior to being processed by the system, the liquid may be processed using an optional UV light and/or filter. A similarly configured inlet header 212 is also located between each of the vessels 210. A part of the inlet header can be an HC1 dosing pump and controller 214 for adjusting the pH of the liquid prior to entering the reactor vessel 210. After the HC1 dosing pump and controller 214 is located an inline mixer 216. The liquid is then directed using a three-way selector valve 218, which allows for the isolation of one or more of the reactors 210 from the rest of the system.

If the three-way selector valve 218 is open to the reactor 210, the liquid travels through an inlet pipe 222 into the reactor, where it is pushed to the bottom of the reactor vessel and is distributed across the bottom of the vessel with the distribution header. The liquid rises up through the suspended bed of media with a retention time of approximately 1 hour. The liquid is then pushed out of the outlet at the roof of the vessel and out the outlet pipe 226. To prevent backflow to the reactor a check valve 228 is present in the outlet pipe 226. Isolation valves 224 may be located in the inlet 222 and discharge pipes 226 to fully isolate a reactor vessel 210. After the liquid exits, or bypasses a reactor vessel 210, a pH sensor 230 reads the pH level and adjusts the pH of the liquid through feedback to the HC1 dosing pump and controller 214. The liquid then travels through one or more of the reactor vessels 210 until it is processed as desired. A tank pressure gauge 220 is also present to verify that the pressure inside the vessels 210 is remaining in the correct range.

After exiting the last reactor vessel 210, the processed liquid may be further cleaned though the use of an option oxidation tank and/or clarifier or settling tank, which are known in the art. The cleaned effluent is then passed out of the system.

The rear view of the system and reaction vessels shown in Figs. 8 and 9 show some of the convenience elements of the preferred design. Once a reactor vessel is filled with media, it is sealed and self-contained. The openings at the top and side of the vessels are sealed against operating and design pressures. The roof 232 of the vessel is designed to avoid gas pockets where potentially harmful gas could accumulate, such designs could preferably include a peaked roof on square vessels or a domed roof on cylindrical vessels. Also, each reactor may have access for lifting equipment 234. Two sealed doors 236 and 238 may also be present. The first sealed door 236 can be used for inspection and filling the media. The second sealed door 238 can be used to empty the vessel. The vessels contain integrated pressure relief valves, which may be present on one of the doors and/or accumulators to accommodate pressure buildups inside. Drain ports or taps 240 may be located at various elevations along the vessel side to facilitate drainage and chemically reactive

substance/adsorbent deactivation. Once the media inside the vessel is consumed, the vessel is isolated, any residual liquid drainage in a controlled manner, and the media is removed.

Spent media has been found to pass TCLP (Toxicity Characteristic Leaching Procedure) and was eligible for disposal in a non-permit required landfill. These should continue to be validated for future applications and installations. The reactor vessel may then be refilled with new media and brought back on line.

Downflow/parallel System Configuration

A preferred embodiment of a treatment system for the treatment of about 25 gallons of liquid per minute in a downflow configuration is shown in Figs. 11-14. There are five reactor vessels 310 arranged in series. Each vessel 310 is sized to treat approximately five gallons per minute, which correlates to an approximate target retention time of one hour, or approximately 300 gallons each. The base dimensions for vessels in this system are 4 ft. diameter and 4 ft. high. The system is also configured so that all valves are accessible from grade level, and that each vessel can be isolated and bypassed individually.

The liquid to be treated enters into the system through an inlet header 312. A similarly configured inlet header 312 is also located between each of the vessels 310. An inlet isolation valve 324 is located between the inlet header 312 and the vessel 310. The inlet isolation valve 324 and an outlet flow control and isolation valve 360 are used to isolate each vessel 310 from the rest of the system, when desired. After the isolation valve 324, there is an inlet flow control valve 358 to control the rate of flow into each vessel 310. The flow may also be controlled using an outlet flow control valve 360. The liquid is transported to the vessel through the inlet pipe 322 and enters through the roof of the vessel. The roof of the vessel may also contain a pressure accumulator 352, a pressure relief valve 354, and an inspection door 356.

The liquid then flows down through the media 101 and is treated by the suspended adsorbents/chemically reactive substances. A purge water header as shown in Fig. 4 and discussed above sits on the screen and is used to reverse flow of liquid through the media 101 to break free any precipitate in or between the media pieces 100. The isolation valves 324 and 360 close during the purge water cycle. The pressure accumulator 352 and pressure relief valve 354 on top of the vessel accommodate the purge pressure, and purge liquid, e.g. water, is provided to the purge header in the tank through the purge pipe 362. Treated liquid and precipitate flow out of the bottom of the tank to the outlet header 226 and may be further processed using known techniques.

Fig. 14 shows the rear of a preferred vessel for use in the downflow, parallel configuration. The side of the vessel may have an access sealed door (not shown). Further, the bottom of the tank 364 is dish-shaped and is flanged to provide access to the internal support screen.

In either system, downflow or upflow, the self-contained vessels are fully modular and may be combined in any variety of ways to suit the physical layout and treatment requirements of a particular source. Vessels may be added, removed, isolated, or bypassed as the levels of pollutants to be treated changes. The system design allows flexibility and scalability to address changing flow rates and pollutant levels. The modular approach also facilitates the optimal use of media and absorbents/chemically reactive substances as each module may be used up to the point when the adsorbent/chemically reactive substance has been consumed before being bypassed and refilled with new media. In certain applications, the removal of pollutants occurs at a decreasing rate across the treatment chain. In such cases, the adsorbent/chemically reactive substance contacting the first stage of liquid flow treats a higher percentage of the pollutants than the later stages. This leads to faster consumption of adsorbent/chemically reactive substance in the earlier parts of the process. The modular design, together with a series configuration allows the operator to replace the media 101 in earlier vessels faster than in later vessels thereby optimizing the life cycle of the overall media and adsorbent/chemically reactive substance.

Spare modules may also be incorporated into the system design to minimize the impact on system flow rates as consumed media is replaced in individual modules. The modular approach facilitates installation and removal of a particular vessel and can be used in short duration, as well as long duration applications. The piping between vessels allows the vessels to be on-line or isolated from the process, which may be accomplished through the use of three-way valves and isolation valves. Preferably, the piping is accessible from grade level, minimizing the need for ladders and platforms, and improving site safety. The piping may be made from steel, PVC, or hosing depending on the operating pressure and level of flexibility desired. Ancillary systems and components such as inlet filters, pumps, oxidizers, clarifiers, pH control dosing systems, valves, and instruments are industry standard systems and components. The system is designed to be easy to run and may be operated or controlled by timers or PLC-based controls.

As those skilled in the art will appreciate, numerous modifications and variations of the present invention are possible in light of these teachings, and all such are contemplated hereby. For example, in addition to the embodiments described herein, the present invention contemplates and claims those inventions resulting from the combination of features of the invention cited herein and those of the cited prior art references which complement the features of the present invention. Similarly, it will be appreciated that any described material, feature, or article may be used in combination with any other material, feature, or article, and such combinations are considered within the scope of this invention.

The disclosures of each patent, patent application, and publication cited or described in this document are hereby incorporated herein by reference, each in its entirety, for all purposes, or at least for the purpose described in the context in which the reference was presented.

Claims

1. A media for removing contaminants from an aqueous stream comprising:

a bed of foam pieces comprising:

a foam substrate;

an adherent coating on a surface of the foam substrate; and a chemically reactive substance and/or an adsorbent adhered to the adherent coating.

2. The media of claim 1, wherein the foam pieces have dimensions between ¼ inch and 3 inches per side.

3. The media of claim 1, wherein the foam pieces have a cuboid shape.

4. The media of claim 3 wherein the foam pieces have dimensions of ½ inch by ½ inch by ½ inch to 1 inch by 1 inch by 1 inch.

5. The media of claim 1, wherein the foam pieces have an irregular shape.

6. The media of claim 1, wherein the chemically reactive substance and/or the adsorbent are selected from the group consisting of bleach, powdered zerovalent iron, activated carbon, carbon, copper, zinc, zeolites, and any combination thereof.

7. The media of claim 1, wherein the chemically reactive substance and/or the adsorbent is powdered zerovalent iron.

8. The media of claim 1, wherein the media is 70 wt.% to 85 wt.% chemically reactive substance and reactive adsorbent, 5 wt.% to 10 wt.% adhesive and 10 wt.% to 25 wt.% foam.

9. The media of claim 1, wherein the foam is reticulated foam and the chemically

reactive substance and/or the adsorbent is a reactive adsorbent.

10. The media of claim 1, wherein the foam has a porosity of at least 80% up to 98%, or 85-98%, or 90-98% or 95-98%.

11. The media of claim 1, wherein the media is granulated and pourable.

12. A system for removing contaminants from a liquid stream comprising:

a vessel with one or more inflow pipes configured to direct the liquid stream to a location in the vessel proximate to a first end of the vessel,

one or more effluent pipes connected to one or more portholes located proximate a second end of the vessel; and

a media as claimed in claim 1 located within the vessel between the one or more inflow pipes and the one or more portholes so as to ensure that flow of the liquid stream passes through the media for removing contaminants from the liquid stream; wherein the system is configured such that the liquid stream flows in the one or more inflow pipes and into the media, out the one or more portholes, and through the one or more effluent pipes, and one or more contaminants are removed from the liquid stream by the media during contact with the media.

13. The system of claim 12, further comprising a diffuser connected to the one or more inflow pipes, said diffuser configured to distribute flow of the liquid stream over a cross-sectional area of the vessel.

14. The system of claim 12, wherein the one or more inflow pipes are located proximate to a bottom of the vessel and the portholes are located proximate to a top of the vessel, both determined when the vessel is upright.

15. The system of claim 12, wherein the media further comprises:

a foam substrate;

an adherent coating a surface of the foam substrate; and a chemically reactive substance and/or an adsorbent adhered to the adherent coating.

16. The system of claim 15, wherein the foam substrate has a cuboid shape.

17. The system of claim 12, wherein the foam substrate has a porosity of at least 80% up to 98%, or 85-98%, or 90-98% or 95-98%.

18. The system of claim 12, wherein the chemically reactive substance and/or the adsorbent is selected from the group consisting of bleach, powdered zerovalent iron, copper, zinc, reducing agents, oxidizing agents, acids, bases, activated carbon, carbon, alumina, diatomaceous earth, zeolites, and any combination thereof.

19. The system of claim 12, wherein the ehcmically reactive substance and/or the

adsorbent is powdered zerovalent iron.

20. The system of claim 12, wherein the foam substrate is reticulated foam.

21. The system of claim 12, wherein the vessel has a capacity of 40-400 gallons and the system is a modular, stand-alone unit.

22. The system of claim 12, wherein there are no moving parts within the vessel.

23. The system of claim 12, wherein the vessel is a first vessel and the system further comprises a second vessel having one or more inflow pipes connected with the one or more effluent pipes of the first vessel.