Mobile carrier for water treatment

Abstract

A migrating biofilm carrier for enhanced wastewater treatment comprises a biopolymer comprising an organic polymer, a filler material, and a densifying material. Also disclosed is a method of domesticating a migrated biofilm carrier for treating wastewater, comprising loading the carrier into a domestication tank, loading a conditioning agent into the domestication tank, and subjecting the carrier and the conditioning agent to aerobic, anaerobic and / or anoxic conditions to provide a domesticated carrier wherein the domesticated carrier has a biofilm disposed on the carrier.

Description

[0001] Citations of relevant applications

[0002] This application claims the benefit of U.S. Application No. 63 / 515,698, filed July 26, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a wastewater treatment method using a migrating biofilm carrier, and more specifically to a method for treating wastewater using an injection-molded / extruded, acclimated, organically filled biocomposite material as a migration carrier. Background Technology

[0004] In addition to traditional phase separation treatment, biological wastewater treatment offers a complementary water treatment process. In biological treatment, wastewater is subjected to microorganisms. These microorganisms can reduce different types of pollutants present in the wastewater and decrease the water's biochemical oxygen demand (BOD). For example, the activated sludge method uses aeration and microorganisms to biologically oxidize pollutants.

[0005] Due to increasingly stringent effluent guidelines for wastewater treatment and increased inflows resulting from increased population and water usage, there remains a need for materials and methods to enhance biological wastewater treatment processes. Summary of the Invention

[0006] In one embodiment, the migratory biofilm carrier for enhancing wastewater treatment includes a biopolymer containing an organic polymer, a filling material, and a densifying material.

[0007] In another embodiment, a method for using an acclimatization carrier to treat wastewater includes loading the carrier into an acclimatization tank, wherein the carrier comprises a biopolymer, a packing material, and a densifying agent. A conditioning agent is loaded into the acclimatization tank, and the carrier and conditioning agent are subjected to aerobic, anaerobic, and / or anoxic conditions to provide an acclimatized carrier, wherein the acclimatized carrier has a biofilm disposed on the carrier.

[0008] The above and other features are illustrated by the following detailed description. Attached Figure Description

[0009] Referring now to the accompanying drawings, which are exemplary embodiments, and in which the same elements are numbered the same.

[0010] Figure 1 This is a schematic cross-sectional view of an implementation method for a biofilm transporter; Figure 2This is a schematic cross-sectional view of an implementation method for a biofilm transporter; Figure 3 This is a graph showing the biochemical oxygen demand (mg / mL) of Example 1 relative to the number of days; Figure 4 This is a graph showing the ammonia concentration (mg / mL) relative to the number of days in Example 1; Figure 5 This is a graph showing the total Kjeldahl nitrogen (TKN) concentration (mg / mL) relative to the number of days in Example 1; and Figure 6 This is a graph showing the total nitrogen concentration (mg / mL) of Example 1 relative to the number of days. Detailed Implementation

[0011] This document discloses a migrating biofilm carrier (hereinafter referred to as the carrier) for enhanced wastewater treatment. The carrier acts as a scaffold for biofilm attachment, growth, and transport during wastewater treatment. The carrier facilitates biofilm transport within and throughout a wastewater treatment system (e.g., an acclimation tank or bioreactor). The carrier comprises a biopolymer, a packing material, and a densifying agent. The densifying agent can adjust the specific gravity of the carrier. The combination of the biopolymer, packing material, and densifying agent can be extruded together to provide a selected surface area, density, and / or porosity.

[0012] Methods for using the carrier are also disclosed. Microbial attachment to the carrier can be acclimated by exposure to inflowing pollutants, returned activated sludge, spent activated sludge, bioaugmentation, and / or biostimulation. During carrier acclimation, biofilm growth can be optimized to provide concentrations suitable for the removal of carbon nutrients and nitrogen and phosphorus components. After the biofilm is deposited on the carrier, it can be brought into contact with wastewater to reduce different types of pollutants present in the wastewater. In this way, the biofilm deposited on the carrier can be used to enhance wastewater treatment processes in terms of predictability, consistency, and throughput.

[0013] "And / or" includes any and all combinations of one or more of the listed items.

[0014] As used in this article, “activated sludge” is defined as an aerated sludge containing a flocculent culture of microorganisms that develop under aeration conditions.

[0015] As used in this article, “bioenhancement” is defined as the addition of microbial strains and / or carbon nutrients to wastewater.

[0016] As used in this article, "biofilm" is defined as at least two types of microorganisms arranged on a surface.

[0017] As used in this article, “biostimulation” is defined as the addition of nitrogen and phosphorus to wastewater.

[0018] As used herein, “polluted water” is defined as water containing at least one contaminant. Untreated wastewater and polluted water are used interchangeably in this document.

[0019] As used in this article, “effective surface area” is defined as the surface area that can be used for biofilm attachment.

[0020] As used herein, “return activated sludge” is defined as precipitated activated sludge that is collected in a selector and returned to the bioreactor to mix with the incoming untreated wastewater.

[0021] As used in this article, "solid residence time" is defined as the time that the solid portion of wastewater spends in a wastewater treatment system.

[0022] As used herein, “excess activated sludge” is defined as sludge removed from wastewater treatment processes. Excess activated sludge contains excess biomass or cell mass and is removed to maintain the biological balance of the wastewater treatment system and / or to achieve a specific solids retention time.

[0023] Biofilm carriers act as scaffold surfaces for microorganisms. These carriers can transport biofilms through wastewater treatment systems. The movement of the carrier through the system is based on its density and settling properties. Biofilms deposited on these carriers enhance biological wastewater treatment processes by improving settling properties, carbon nutrition, and the removal of phosphorus and nitrogen components.

[0024] like Figure 1 As shown, the carrier 100 may include a biopolymer 101, a filler material 103, and a densifying agent 102. The carrier may be compostable and / or biodegradable. The carrier may be injection molded or extruded. Figure 1 As shown, the carrier 100 can be in a core-shell form, wherein the biopolymer 101 partially or completely encapsulates the core of the filler material 103 and the densifying agent 102. In one aspect, the biopolymer 101, the filler material 103, and the densifying agent 102 can be as follows: Figure 2The mixture shown is, for example, uniformly distributed throughout the carrier. Biopolymer 101, filler 103, and densifying agent 102 can be distributed uniformly or non-uniformly throughout the carrier. When the materials are distributed non-uniformly, biopolymer 101, filler 103, and densifying agent 102 can be distributed in layers or concentration gradients within the carrier 100. A distributed mixture of biopolymer 101, filler 103, and densifying agent 102 in the carrier 100 can be formed by co-extrusion of the mixture. The carrier 100 can be non-absorbent, neutrally charged, and / or inert. Molding and / or extrusion of the moving carrier 100 can provide irregular surfaces with dimping, pores, etc. Irregular surfaces can promote biofilm attachment to the carrier, protect biofilm growth, increase total and effective surface area, and provide redox zones for differentiation on the carrier. For example, the outermost surface of the carrier may be exposed to redox conditions different from those on the surface area covered by the interior of the carrier 100. The carrier 100 may be manufactured entirely to a predetermined size, density, and / or surface area. The controlled physical and chemical properties of the carrier 100 can improve the consistency and predictability of wastewater treatment processes.

[0025] The carrier 100 can be a three-dimensional shape having a length, width, and height of about 500 micrometers to about 3 millimeters. In some embodiments, the carrier 100 is generally spherical, having a diameter of about 500 micrometers to about 3 millimeters. The total surface area of ​​the carrier 100 can be about 0.02 square meters per gram (m²). 2 / g) to about 5 m 2 / g. The specific gravity of carrier 100 can be from about 1 to about 5.

[0026] The core of carrier 100 may contain filler material 103. Filler material 103 may be organic material and / or recycled material. Suitable filler materials include cellulose, lignocellulose, moss, algae, and mollusc shells. Filler material 103 may be from about 5 wt% to about 95 wt%, from about 10 wt% to about 75 wt%, or from about 25 wt% to about 50 wt% of the total weight of carrier 100.

[0027] The biopolymer 101 of the carrier 100 can be an organic polymer, primarily disposed on the exterior of the filler 103 and densifier 102, or the biopolymer 101 can be uniformly or non-uniformly mixed with the filler 103 and densifier 102. The biopolymer 101 can be molded or extruded together with the filler 103 and densifier 102. The biopolymer 101 can be configured to provide a porous surface for the carrier 100.

[0028] Suitable biopolymers include polylactic acid (PLA), polypropylene (PP), high-density polyethylene (HDPE), acrylonitrile-butadiene-styrene (ABS), low-density polyethylene (LLDPE), high-impact polystyrene (HIPS), or combinations thereof. In some embodiments, the biopolymer may be biodegradable. Examples of suitable biodegradable polymers are polylactic-glycolic acid (PLGA), polycaprolactone (PCL), copolymers of polylactic-glycolic acid and polycaprolactone (PCL-PLGA copolymer), polyhydroxybutyrate-valerate (PHBV), polyorthoester (POE), polyethylene oxide-butylene terephthalate (PEO-PBTP), poly-D,L-lactic acid-p-dioxanone-polyethylene glycol block copolymer (PLA-DX-PEG), etc., or combinations comprising at least one of the aforementioned biodegradable polymers.

[0029] In some embodiments, biopolymer 101 may comprise a mixture of about 5 wt% to about 30 wt% of the total weight of biopolymer 101. Biopolymer 101 may be about 1 wt% to about 99 wt%, 2 wt% to 75 wt%, 5 wt% to about 30 wt%, or about 2 wt% to about 15 wt% of the total weight of carrier 100.

[0030] Densifying agent 102 can be an organic or inorganic compound. In some embodiments, densifying agent 102 may include an organic compound having a hydroxyl functional group to increase hydrogen bonding in the filler core of the support. Suitable densifying agents include calcium salts, iron salts, granular activated carbon, and combinations thereof. In some embodiments, densifying agent 102 may include a metal (e.g., iron) or a Group II salt, such as a calcium salt, strontium salt, barium salt, or combinations thereof. For example, densifying agent 102 may be calcium carbonate, ferric chloride, barium chloride, iron, etc. In one embodiment, densifying agent 102 may include two, three, or four organic or inorganic compounds. For example, when densifying agent 102 includes two organic or inorganic compounds, these two organic or inorganic compounds may be present in a 1:1 ratio, a 1:2 ratio, a 1:3 ratio, a 1:4 ratio, etc. The densifying agent 102 may be about 0.2 wt% to about 75 wt%, 2 wt% to about 60 wt%, about 5 wt% to about 50 wt%, or about 10 wt% to about 25 wt% of the total weight of the carrier 100.

[0031] During and / or prior to wastewater treatment, biofilm biomass is placed on a migrating biofilm carrier 100. Biofilm biomass includes microorganisms such as bacteria and protozoa. Biofilm biomass can be of a single species or multiple species. The species of microorganisms used for biofilm biomass are selected based on the composition of the incoming contaminated water, the redox conditions of the bioreactor, and the solids retention time (SRT). Biofilm biomass is used to biodegrade components contained in the contaminated water, such as phosphorus and nitrogen-containing chemicals and nutrients such as carbonaceous materials. Appropriate species selection and concentration of biofilm biomass improve nutrient carbon removal, reduce suspended fine solids, and reduce total suspended solids.

[0032] Applying biofilms mounted on a carrier to wastewater improves the efficiency and capacity of wastewater treatment. The use of this composition saves time, reduces treatment costs, and increases the system's processing capacity.

[0033] Methods for acclimating a carrier for wastewater treatment may include acclimating the carrier 100 in an acclimation tank. The carrier 100 may be loaded into the acclimation tank and treated to one or more combinations of redox conditions, such as aerobic, anaerobic, and / or anoxic. In the acclimation tank, the carrier 100 may be treated for 1 hour, 12 hours, 1 day, or 7 days to provide an acclimated carrier. Within the acclimation tank, the carrier 100 may be treated with untreated wastewater influent, returned activated sludge, spent activated sludge, bio-enhancing, and / or biostimulation. Selected treatments or combinations of treatments of the carrier within the acclimation tank promote biofilm growth on the carrier under acclimation conditions. Conditioners may be loaded into the acclimation tank in combination with the carrier. Conditioners may include seed microorganisms. Seed microorganisms may be contained in untreated wastewater influent, returned activated sludge, spent activated sludge, bio-enhancing, and / or biostimulation. In some embodiments, seed microorganisms may include nitrifying bacteria, denitrifying bacteria, methanogens, Gram-negative bacteria, heterotrophic bacteria, or combinations thereof.

[0034] Wastewater treatment methods may include loading a carrier 100 into a wastewater treatment system. In some embodiments, the carrier 100 is acclimated before being loaded into the wastewater treatment system. A biofilm is placed on the carrier after contact with wastewater in the wastewater treatment system or after the carrier 100 has been acclimated. The carrier with the biofilm disposed thereon can be transported throughout the wastewater treatment system. As the acclimated carrier migrates through the wastewater treatment system, the biofilm on the carrier comes into contact with the wastewater. The biofilm on the carrier reduces the carbon nutrients and nitrogen and phosphorus content in the wastewater, thereby providing treated wastewater. The biofilm on the carrier enhances the wastewater treatment process by increasing predictability, consistency, and throughput.

[0035] The present disclosure will be described in more detail below through the following embodiments, but the technical scope of the present disclosure is not limited thereto.

[0036] Example

[0037] Measurements of various water quality variables were collected using the Standard Methods for the Examination of Water and Wastewater from different wastewater treatment systems. Details of the sampled water quality variables are listed in Table 1.

[0038] Table 1. Abbreviations for Water Quality Variables

[0039] Example 1. Performance of a wastewater system with gravity sludge selection and biofilm carrier system

[0040] Several wastewater quality variables were evaluated for a modified Ludzack-Ettinger (MLE) process wastewater treatment system with a flow rate of 1.7 million gallons per day, equipped with a particle size selector downstream of a gravity sludge selection system (i.e., clarifier, etc.). Daily measurements for influent and effluent samples over a 6-month period are shown below. Figures 2 to 5 In the middle. For example Figures 2 to 5 As shown, the system effectively reduces the biochemical oxygen demand (BOD), ammonia concentration (NH3), total Kjeldahl nitrogen (TKN), and total nitrogen (TN) from the influent to the effluent.

[0041] On day 115, the biofilm carrier system, including the disclosed carrier 100, was installed in the wastewater treatment system. The average values ​​of ammonia, TKN, and TN in the effluent decreased after the installation of the biofilm carrier system, and the variation in the data also decreased (i.e., the standard deviation decreased), see Table 2. Therefore, applying the disclosed carrier 100 to the wastewater treatment system can provide improved process consistency and efficiency.

[0042] Table 2. Average nitrogen concentration

[0043] While this disclosure has been described with reference to preferred embodiments, those skilled in the art will understand that various changes can be made without departing from the scope of this disclosure, and equivalents can replace its elements. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of this disclosure without departing from the essential scope of this disclosure. Therefore, it is intended that this disclosure be limited to the specific embodiments disclosed as the best mode contemplated for carrying out this disclosure, but rather that this disclosure will include all embodiments falling within the scope of the appended claims.

Claims

1. A migratory biofilm carrier for enhancing wastewater treatment, comprising: Biopolymers, including organic polymers; Filler material; and Densified materials.

2. The migration biofilm carrier according to claim 1, wherein, The migration biofilm carrier is a three-dimensional shape with a length, width, and height of approximately 500 micrometers to approximately 3 millimeters.

3. The migration biofilm carrier according to claim 1, wherein, The migration biofilm carrier has a total surface area of ​​approximately 0.02 m² / g to approximately 5 m² / g.

4. The migration biofilm carrier according to claim 1, wherein, The migration biofilm carrier has a specific gravity of about 1 to about 5.

5. The migration biofilm carrier according to claim 1, wherein, The biopolymer is polylactic acid, polypropylene, polyethylene, acrylonitrile-butadiene-styrene, low-density polyethylene, high-impact polystyrene, polylactic acid-glycolic acid, polycaprolactone, copolymers of polylactic acid-glycolic acid and polycaprolactone, polyhydroxybutyrate-valerate, polyorthoester, polyethylene oxide-butylene terephthalate, poly-D,L-lactic acid-p-dioxane-polyethylene glycol block copolymer, or combinations thereof.

6. The migration biofilm carrier according to claim 1, wherein, The biopolymer comprises approximately 1 wt% to approximately 99 wt% of the total weight of the migrating biofilm carrier.

7. The migration biofilm carrier according to claim 1, wherein, The filling material is cellulose, lignocellulose, moss, algae, mollusc shell, or a combination thereof.

8. The migration biofilm carrier according to claim 1, wherein, The filling material comprises approximately 5 wt% to approximately 95 wt% of the total weight of the migration biofilm carrier.

9. The migration biofilm carrier according to claim 1, wherein, The densifying material is a metal, a group II metal salt, an iron salt, granular activated carbon, or a combination thereof.

10. The migration biofilm carrier according to claim 1, wherein, The densifying material comprises approximately 0.2 wt% to approximately 75 wt% of the total weight of the migrating biofilm carrier.

11. A method for using a domestication carrier to treat wastewater, comprising: The carrier is loaded into an acclimatization tank, wherein the carrier comprises a biopolymer, a filler material, and a densifying agent; The regulator is added to the acclimatization tank; as well as The carrier and the regulator are subjected to aerobic, anaerobic and / or hypoxic conditions to provide a domesticated carrier, wherein the domesticated carrier has a biofilm disposed on the carrier.

12. The method according to claim 11, wherein, The regulator is a seed microorganism.

13. The method according to claim 12, wherein, The seed microorganisms are found in untreated wastewater influent, recycled activated sludge, and / or waste activated sludge.

14. The method according to claim 12, wherein, The seed microorganisms are nitrifying bacteria, denitrifying bacteria, methanogens, Gram-negative bacteria, heterotrophic bacteria, or a combination thereof.

15. The method of claim 11, further comprising loading the domesticated carrier into a wastewater treatment system.

16. The method according to claim 15, wherein, The domesticated carrier is transported in the wastewater treatment system.

17. The method according to claim 16, wherein, The biofilm disposed on the carrier is brought into contact with wastewater to provide treated wastewater with reduced carbon nutrients and nitrogen and phosphorus content.

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