WO2024256906A1 - Système et procédé de traitement des déchets biologiques solides et liquides - Google Patents

Système et procédé de traitement des déchets biologiques solides et liquides Download PDF

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WO2024256906A1
WO2024256906A1 PCT/IB2024/055336 IB2024055336W WO2024256906A1 WO 2024256906 A1 WO2024256906 A1 WO 2024256906A1 IB 2024055336 W IB2024055336 W IB 2024055336W WO 2024256906 A1 WO2024256906 A1 WO 2024256906A1
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tank
anaerobic digestion
sludge
digestion tank
batch reactor
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Victor LOBANOV
Thomas Bjelkeman-Pettersson
George PATE
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Stremtech AB
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Stremtech AB
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/28—Anaerobic digestion processes
    • C02F3/286—Anaerobic digestion processes including two or more steps
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/02—Biological treatment
    • C02F11/04—Anaerobic treatment; Production of methane by such processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/105—Phosphorus compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/16—Nitrogen compounds, e.g. ammonia
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/22—Nature of the water, waste water, sewage or sludge to be treated from the processing of animals, e.g. poultry, fish, or parts thereof
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/02—Temperature
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/06—Controlling or monitoring parameters in water treatment pH
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/22—O2
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/24—CO2
    • C02F2209/245—CO2 in the gas phase
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/28—CH4
    • C02F2209/285—CH4 in the gas phase
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/006—Regulation methods for biological treatment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/02—Aerobic processes
    • C02F3/12—Activated sludge processes
    • C02F3/1236—Particular type of activated sludge installations
    • C02F3/1263—Sequencing batch reactors [SBR]
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/32—Biological treatment of water, waste water, or sewage characterised by the animals or plants used, e.g. algae
    • C02F3/327—Biological treatment of water, waste water, or sewage characterised by the animals or plants used, e.g. algae characterised by animals and plants
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used
    • C02F3/345—Biological treatment of water, waste water, or sewage characterised by the microorganisms used for biological oxidation or reduction of sulfur compounds
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E50/00—Technologies for the production of fuel of non-fossil origin
    • Y02E50/30—Fuel from waste, e.g. synthetic alcohol or diesel

Definitions

  • the present invention relates to a system and a method for treatment and remineralization of solids and liquid biowaste, comprising a settling tank with optional coagulant addition, one or more anaerobic digestion tank comprising an anaerobic digestion microbial community, a gas collection tank, a sequential batch reactor adapted to receive a digested product from the anaerobic digestion tank comprising an aeration supply device to add oxygen to the digested product and a digestive microbial community, a solid collection tank adapted to receive solids from the sequential batch reactor, and a filtration tank adapted to remove and filter supernatant from the sequential batch reactor and filter the supernatant prior to discarding the liquid.
  • a smaller version of this concept is sometimes used in a backyard or very small-scale aquaponic farms, which may use a portion of the effluent to supplement nutritional needs in hydroponic beds.
  • Direct application of this stream to hydroponic cultivation systems can lead to biofouling and will suffocate the roots of oxygen. As such, the waste stream in its entirety is not directly suitable for hydroponics cultivation.
  • Constructed wetlands are similar to settling basins with the benefit being that maintenance needs are initially low, but they are relatively land-intensive and removal efficiency decreases over time, necessitating complete periodic restoration. Constructed wetlands require a larger land footprint than settling basins.
  • Lobanov Frontiers in plant science, June 2021, vol 12 [4] describes a strategy to improve the trace nutrient profile of crops grown in an aquaponics system. It uses a settlingtank, anaerobic anaerobic digestion tank, and a sequential batch reactor to break down the solids and remineralize the nutrients. This article does not describe a feedback loop to optimize growth, nor any information about the use of a methanogenic community to produce methane.
  • US2021/0147274 discloses a method of reducing nitrogen and phosphorus recycled back to a liquid stream by subjecting digested sludge to post aerobic digestion in the presence of at least one alkaline compound containing calcium. The method cannot be automated and central control of all method steps is not possible.
  • the system can be performed in an automated process with the potential for economic returns to the user through among others the valorization of biogas and fertilizers.
  • the invention relates to system for treatment and remineralization of solids and liquid biowaste, comprising or consisting of
  • a settling tank adapted to receive sludge as biowaste and allow the sludge to concentrate through settling, optionally comprising one or more first coagulant adapted to coagulate the solids in the sludge,
  • anaerobic digestion tank adapted to receive the sludge from the settling tank in the form of concentrated sludge, comprising an anaerobic digestive microbial community adapted to digest an amount of sludge over a period, wherein at least one digestive microbial community is a methanogenic community adapted to produce methane from sludge, and optionally comprising one or more second coagulant adapted to coagulate the solids in the sludge,
  • a sequential batch reactor adapted to receive a digested product from the one or more anaerobic digestion tank comprising an aeration supply device to add oxygen to the digested product and an aerobic digestive microbial community for further digestion by sequestering nitrogen and phosphorus compounds, prior to removal of the liquid to a plant or hydroponic cultivation system,
  • a solid collection tank adapted to receive solids from the sequential batch reactor
  • a filtration tank adapted to remove and filter supernatant from the sequential batch reactor and filter the supernatant priorto discarding the liquid.
  • the system comprises a control system for optimizing the output in the anaerobic digestion tank, the sequential batch reactor, the gas collection tank, the solids collection tank and/or the filtration tank by constantly measuring and controlling a temperature, pH, solid retention time (SRT), organic loading rate (OLR), nitrate and ammonia concentration and total nitrogen of the sludge, carbon:nitrogen (C:N) ratio, dissolved oxygen (DO) and a methane:carbon dioxide ratio, and disclaiming the use of alkaline compounds containing calcium in the sequential batch reactor.
  • a control system for optimizing the output in the anaerobic digestion tank, the sequential batch reactor, the gas collection tank, the solids collection tank and/or the filtration tank by constantly measuring and controlling a temperature, pH, solid retention time (SRT), organic loading rate (OLR), nitrate and ammonia concentration and total nitrogen of the sludge, carbon:nitrogen (C:N) ratio, dissolved oxygen (DO) and a methane:carbon dioxide ratio, and disclaiming the
  • use of alkaline compounds containing calcium in the system is disclaimed.
  • use of calcium hydroxide in the system is disclaimed.
  • use of calcium hydroxide in the sequential batch reactor is disclaimed. Without calcium, especially calcium hydroxide, the system and method of the invention is more environmentally friendly. Further, corrosion can be prevented and costs can be reduced.
  • the one or more anaerobic digestion tank comprises a first anaerobic digestion tank adapted for conversion of sludge into gases, such as methane and carbon dioxide, and a second anaerobic digestion tank adapted for phosphorus remineralization of the sludge, whereby the second anaerobic digestion tank is adapted to receive the digested product from the first anaerobic digestion tank.
  • the invention relates to a system for treatment and remineralization of solids and liquid biowaste, comprising or consisting of
  • a settling tank adapted to receive sludge as biowaste and allow the sludge to concentrate through settling, optionally comprising one or more first coagulant adapted to coagulate the solids in the sludge,
  • a first anaerobic digestion tank adapted to receive the sludge from the settling tank in the form of concentrated sludge, comprising an anaerobic digestive microbial community adapted to digest an amount of sludge over a period for conversion of sludge into gases, such as methane and carbon dioxide, wherein at least one digestive microbial community is a methanogenic community adapted to produce methane from sludge,
  • a second anaerobic digestion tank adapted for phosphorus remineralization of the sludge, optionally comprising one or more second coagulant adapted to coagulate the solids in the sludge,
  • SBR sequential batch reactor
  • a solid collection tank adapted to receive solids from the sequential batch reactor
  • a filtration tank adapted to remove and filter supernatant from the sequential batch reactor and filter the supernatant priorto discarding the liquid.
  • the system comprises a control system for optimized regulation of flow rates and the output quality in the anaerobic digestion tanks, the sequential batch reactor, the gas collection tank, the solids collection tank, the selected effluent output system as direct discharge , the filtering tank, or to a sump by constantly measuring and controlling a temperature, pH, solid retention time (SRT), organic loading rate (OLR), dissolved oxygen (DO), and chemical additions (sulfur, iron, readily bioavailable carbon).
  • SRT solid retention time
  • OLR organic loading rate
  • DO dissolved oxygen
  • chemical additions sulfur, iron, readily bioavailable carbon
  • the digestive microbial community of the first anaerobic digestion tank is a methanogenic microbial community adapted to produce methane from the sludge.
  • the second anaerobic digestion tank is a sulfur redox community to which a second iron coagulant and sulfur may be added to promote phosphorus solubilization.
  • the (second) anaerobic digestion tank comprises an iron coagulant.
  • the (second) anaerobic digestion tank comprises sulfur.
  • the sequential batch reactor acts as an enhanced biological phosphorus removal (EBPR) system to which a readily bioavailable carbon source is added to allow for phosphorus and nitrogen sequestration.
  • bioavailable carbon sources may include any carbon source derived from sugars or fatty acids. In the purest sense this may be a refined product such as sucrose, howeverthis system accommodatesthe use of byproducts from other industries that meet the requirement for bioavailability.
  • Sources may include beverage wastes, sugar refining wastes, distillery wastes, among otherfood processing waste streams.
  • a carbon source is selected from the group comprising or consisting of sugars, fatty acids, beverage wastes, sugar refining wastes, distillery wastes or other food processing waste streams and any mixtures thereof.
  • the filtration system comprises or consists of a biochar filter to remove any residual suspended solids and micropollutants creating an effluent with phosphorus, nitrogen, and carbon concentrations safe for discharge.
  • the entire system is managed by a control system to optimize the activity of each microbial community based on the flow rates through each tank.
  • This comprises or consists of prioritizing methane production in the (first) anaerobic digestion tank, phosphorus solubilization in the (second) anaerobic digestion tank, and phosphorus and nitrogen sequestration in the sequential batch reactor.
  • the control system achieves these goals by constantly measuring and controlling temperature, pH, solid retention time (SRT), organic loading rate (OLR), dissolved oxygen (DO) and chemical additions (sulfur, iron, readily bioavailable carbon).
  • the settling tank comprises one or more filters, such as drum filters to filter the supernatant in said tank.
  • the settling tank features a first coagulant dispenser.
  • the first coagulant facilitates the precipitation of solids and also provide an essential nutrient to promote methanogenesis in the anaerobic digestion tank.
  • the first and/or second coagulant is selected from the group comprising iron, manganese or aluminum or a mixture or salts thereof.
  • the system further comprises or consists of a sump tank adapted to receive liquid from the sequential batch reactor tank adapted to add nutrients to the liquid prior to transfer of the liquid to a plant or hydroponic cultivation system.
  • nutrients are added to the (second) anaerobic digestion tank comprising sulfur, iron, and a readily bioavailable carbon source.
  • sulfur is added to the (first) anaerobic digestion tank.
  • the coagulants are selected from the group comprising or consisting of iron, manganese or aluminum or a mixture or salts thereof. In some aspects, the coagulant is selected from the group comprising or consisting of iron or manganese or a mixture or salts thereof.
  • the first and/or second coagulant is iron or salts thereof.
  • Ferric chloride is simple, relatively cheap, and effective at low concentrations compared to other iron-based coagulant.
  • the first and/or second coagulant is manganese or salts thereof. Magnetite or manganese has the potential to be used in a regenerative coagulation distribution system at higher implementation cost but lower material costs in the long-term.
  • the first and/or second coagulant is recycled.
  • the first coagulant is dispersed (automatically) as a liquid into the settling tank.
  • the second coagulant is (automatically) dispersed into or added to the (second) anaerobic digestion tank.
  • the use of iron coagulants is preferred due to its safety compared to aluminum coagulants for human health and its function to outcompete phosphorus and thereby enable greater phosphorus solubilization. It improves the effectivity and efficiency of the system and method of the invention.
  • the digestive microbial community in the SBR is selected from the group comprising nitrifiers and phosphate-accumulating organisms (PAOs).
  • the invention also relates to a method for treatment and remineralization of solids and liquid biowaste, comprising or consisting of
  • Step 1) providing sludge as biowaste to one or more anaerobic digestion tank comprising a digestive microbial community and optionally a first coagulant,
  • Step 2 adapting the anaerobic digestive microbial community to digest an amount of sludge over a period, to establish a methanogenic community
  • Step 3) removing gas from the one or more anaerobic digestion tank into a gas collection tank, Step 4) adapting and controlling a biogas production rate and a methane:carbon dioxide ratio in the gas collection tank,
  • Step 5 providing sludge from the anaerobic digestion tank to a sequential batch reactor comprising a digestive microbial community suitable for enhanced biological phosphorus removal and aerating said digested sludge from the one or more anaerobic digestion tank,
  • Step 6a removing liquid from the sequential batch reactor for use in a hydroponic cultivation system, and/or
  • Step 6b) removing liquid from the sequential batch reactor to a sump tank adapted to add nutrients to the liquid, prior to use of the liquid in the hydroponic cultivation system, and/or
  • Step 6c) removing liquid from the sequential batch reactor to a filtration tank to remove any residual impurities prior to discharge of the liquid as a neutralized effluent safe to the environment, or a sump or removal of the liquid to a plant or hydroponic cultivation system, and/or
  • Step 6d) removing liquid enriched with phosphorus and nitrogen from the sequential batch reactor (3) to precipitated as a mineral fertilizer such as struvite,
  • Step 7) removing solids from sequential batch reactor to a solid collection tank, and optimizing the method by controlling the output in the anaerobic digestion tank, the sequential batch reactor, the gas collection tank, the solids collection tankand/orthe filtration tank by constantly measuring and controlling a temperature, pH, solid retention time (SRT), organic loading rate (OLR), dissolved oxygen (DO) and a methanexarbon dioxide ratio.
  • SRT solid retention time
  • OLR organic loading rate
  • DO dissolved oxygen
  • a first and a second additional anaerobic digestion tank is used in the method and steps 1) to 5) comprise
  • Step 1) providing sludge as biowaste to a first anaerobic digestion tank comprising a digestive microbial community.
  • Step 2 adapting an anaerobic digestive microbial community to digest an amount of sludge over a period, to establish a methanogenic community
  • Step 3 removing gas from the first anaerobic digestion tank into a gas collection tank
  • Step 4) adapting and controlling a biogas production rate and a methane: carbon dioxide ratio in the gas collection tank,
  • Step 5 providing sludge from the second anaerobic digestion tank to a sequential batch reactor comprising a digestive microbial community suitable for enhanced biological phosphorus removal and aerating said digested sludge from the second anaerobic digestion tank.
  • step 1) includes a step la) of providing sludge as biowaste in the settling tank to settle the sludge, and step lb) adding a coagulant before transfer of the sludge to the anaerobic digestion tank.
  • a second coagulant or an iron coagulant is added to the (second) anaerobic digestion tank, In some aspects, sulfur is added to the (second) anaerobic digestion tank.
  • nutrients are added to the second anaerobic digestion tank comprising sulfur, iron, and a readily bioavailable carbon source.
  • the first and/or second coagulant is selected from the group comprising iron, manganese or aluminum or a mixture or salts thereof. In some aspect, the first and/or second coagulant is iron.
  • the SBR digestive microbial community is selected from the group comprising nitrifiers and phosphate-accumulating organisms (PAOs).
  • the control system regulates input/output and environmental conditions related to the treatment of the biowaste or waste stream with the goal of optimizing output quality and maintaining system stability under dynamic waste stream flows.
  • the control system integrates multiple disciplines togetherto create a product more suitable forthe target audience (animal husbandry or aquaculture-related facility with point source collection of animal feces).
  • the control system has a simple and intuitive design that any employee can learn to use, meaning the training time is minimal.
  • the control system regulates outputs based on the needs of the facility ranging from an exclusive focus on mitigating discharge costs and pollution potential to optimizing the remineralization of nutrients for on site, downstream plant cultivation.
  • the system and method of the invention improve flexibility for treatment of biowaste. Less space is needed using the system of the invention.
  • Anaerobic digestion in biowaste or wastewater treatment focuses on municipal waste or industrial wastes with the express purpose of mitigatingthe pollution potential ofthe effluent. While this is integral to the solids treatment system described here, the system and method of the invention also seeks to efficientlyze all outputs.
  • the system integrates solids treatment into aquaculture facilities, modifying existing systems by adapting the waste stream characteristics to the wastewater treatment process, and targets potential outputs to maximize usefulness to aquaculture facilities.
  • Waste stream characteristics include: elemental composition (identification of the macronutrient ratios and identification of micronutrient deficiencies relevant to the microbial populations in the target wastewater treatment process), digestibility analysis such as duration forthe microbial community to decompose the waste stream, and determination of which factors in the waste stream may limit the process, and the biomethane potential, such as gas composition, production rate, best capture method, considerations whether scrubbing (removal of toxic gaseous compounds) is required.
  • elemental composition identification of the macronutrient ratios and identification of micronutrient deficiencies relevant to the microbial populations in the target wastewater treatment process
  • digestibility analysis such as duration forthe microbial community to decompose the waste stream, and determination of which factors in the waste stream may limit the process
  • biomethane potential such as gas composition, production rate, best capture method, considerations whether scrubbing (removal of toxic gaseous compounds) is required.
  • Both system and method are easy to use.
  • the machine learning algorithm helps tailor the operation conditions to the local facility. Critically,
  • Biogas production is the main metric of success.
  • Biogas is a mixed gaseous product composed of methane, carbon dioxide, and trace amounts of other gases.
  • methane and carbon dioxide are one of the target compounds.
  • Methane is used for energy generation (combustion either to heat water or to generate electricity).
  • Carbon dioxide is used to augment plant growth in controlled environment agriculture systems (such as hydroponics and aquaponics).
  • Biogas also creates a mechanism to remove carbon from the waste stream. Thus reducing the carbon foot print. This is also important as the effluent is otherwise subject to discharge regulation and expenses, where wastewater treatment systems charge a fee for the amount of carbon-rich suspended solids in an effluent. It is also subject to discharge regulations by environmental protection agencies.
  • carbon-rich waste streams are unsuitable for hydroponic cultivation as they stimulate heterotrophic bacterial growth, decreasing the oxygen concentration of the water column and suffocating plant roots.
  • the system and method of the invention reduce the risk for eutrophication.
  • an in-depth characterization of the waste stream source Prior to using any novel waste stream for biogas production, an in-depth characterization of the waste stream source is needed. Once this is done, initial operational parameters may be estimated based on the amount of aquaculture solids produced in the system, the amount of time required for their maximal conversion to biogas, the treatment system reactor volumes required to meet waste stream production and achieve maximal output rates. After the system is running, minor adjustments in the flow rates are required to compensate for changing environmental conditions (e.g., ambient temperature, fish growth) in order to maintain an optimal biogas producing environment. Reasons for these adjustments are numerous: changes in ambient temperature, changes in waste stream volume produced, which for example depends on the number of fish being raised, which changes as new fish are added in batch and older fish are sold off.
  • environmental conditions e.g., ambient temperature, fish growth
  • a warning system based on divergence of parameters from normal operating behavior. This will allow operators without extensive knowledge of the importance of individual parameters to adjust and interpret results.
  • the system is able to adjust operational parameters to compensate for these changes, for example modulating the organic loading rate or temperature to accelerate or retard microbial activity.
  • the system allows for different outputs. Besides biogas production, the system of the invention can also produce a fertilizer or a discharge-friendly effluent.
  • the form of the fertilizer output is variable. It may be a liquid stream (ideal for downstream hydroponic cultivation), or a solid substrate (granular substrate rich in phosphorus and nitrogen, or a nitrogen-enriched biochar) depending on the requests of the client.
  • An advantage of solid substrate fertilizer outputs is to allow facilities to produce a fertilizer without needing to export large volumes of water, as would be the case with the liquid fertilizer. This reduced the overall costs and carbon foot print.
  • the digestive microbial community is selected from archaea and bacteria.
  • anaerobic digestion involves interconnected groups of microorganisms that coordinate to perform a range of tasks: hydrolysis, acidogenesis, acetogenesis, and methanogenesis.
  • hydrolysis complex organic compounds are broken down into simpler sugars and organic acids.
  • acidogenesis these sugars and organic acids are further metabolized into more simple organic acids, alcohols, aldehydes, and gases like carbon dioxide and hydrogen.
  • acetogenesis the organic acids are converted into volatile fatty acids (VFA), especially short chain fatty acids.
  • VFA volatile fatty acids
  • the methanogens themselves are typically limited to a narrow range of carbon and energy sources: CO, CO2/H2, formate, acetate, methanol, and methylamines, and CO.
  • the (second) anaerobic digestion tank microbial community is selected from the group comprising or consisting of sulfur cycling bacteria. In the presence of the added sulfur and iron coagulant, these bacteria facilitate the solubilization of phosphorus.
  • the first anaerobic digestion tank comprises or consists of an anaerobic digestion community microbial community selected from the group comprising or consisting of Methanobacterium thermoautotrophicum, Methanobrevibacter ruminantium, Methanosarcina barkeri, Methanosaeta concilii, Methanococcus maripaludis, Bacteroides thetaiotaomicron, Clostridium aceticum, Acetobacterium woodii, Clostridium spp. and Syntrophomonas sp..
  • the (second) anaerobic digestion tank comprises or consists of a sulfur cycling community selected from the group comprising or consisting of Acid ith iobacillus thiooxidans, Thiomonas intermedia and Thiomonas perometabolis.
  • the sequential batch reactor microbial community is selected from the group comprising or consisting of nitrifiers (ammonia oxidising archaea and bacteria, nitrite oxidising bacteria and commamox) and phosphate-accumulating organisms (PAOs).
  • the sequential batch reactor microbial community is selected from the group comprising or consisting of nitrifiers and phosphate-accumulating organisms (PAOs).
  • the nitrifiers are selected from the group comprising or consisting of ammonia oxidising archaea and bacteria, nitrite oxidising bacteria and commamox.
  • the sequential batch reactor tank comprises or consists of an aerobic digestive community microbial community selected from the group comprising or consisting of Accumulibacter phosphatis, Tetrasphaera elongata, Candidatus Competibacter phosphatis, Candidatus Propionivibrio ammoniiproducens, Candidatus Brocadia anammoxidans and Candidatus, such as Microthrix parvicella, Nitrosomonas europaea, Nitrosococcus oceani, Nitrosospira multiformis, Nitrospira moscoviensis and Nitrobacter winogradskyi.
  • an aerobic digestive community microbial community selected from the group comprising or consisting of Accumulibacter phosphatis, Tetrasphaera elongata, Candidatus Competibacter phosphatis, Candidatus Propionivibrio ammoniiproducens, Candidatus Brocadia anammoxidans and Candidatus, such as Microthrix parvicella, Nitrosomonas europaea, Nitrosococcus
  • the sequential batch reactor further comprises or consists of the following aerobic digestive community microbials, when a low oxygen environmentis is demanded, selected from the group comprising or consisting of Nitrosomonas europaea, Nitrospira moscoviensis, Nitrobacter winogradskyi, Pseudomonas stutzeri, Paracoccus denitrificans and Alcaligenes faecalis.
  • strains/species will be similar but not identical in each place where the system and methods are installed. The variation in strains/species will also vary depending on geographical and environmental differences as well as differences in start materials.
  • the system and method of the invention allow for optimizing the performance of the microbials depending on the desired output of the system.
  • the parameters of the anaerobic digestion tank will be maintained between specific ranges and modified by the control system to prioritize biogas production under dynamic conditions.
  • the temperature is from 18 to 30°C or from 20 to 28°C
  • the pH is from 6 to 9, or from 6.5 to 7.5
  • the solid retention time (SRT) calculated as tank volume/feeding rate of tank is from 15 to 80 days, or 20 to 50 days or 40 days
  • the carbon: nitrogen (C:N) ratio is from more than 4.5 or more than 6
  • the methane: carbon dioxide ratio is from 3 to 5: 1.
  • the dissolved oxygen (DO) will be maintained from 0 to 2 mg/l or 0.5 to 2 mg/l. The DO depends on whether the goal is to produce an effluent for hydroponics cultivation or a neutralized effluent to be discharged in the environment.
  • the carbon:nitrogen (C:N) ratio is from more than 4.5 or more than 6, and the methane:carbon dioxide ratio is from 3 to 5: 1.
  • step 2) organic material is added.
  • Other waste streams may be added to produce biogas from multiple sources and increase the circularity of the farm's resources. For example, agricultural wastes or manure of other animals may be added.
  • step 5 air is supplied in a cycle of air supply for 20 to 30 minutes, then no air supply for 20 to 30 minutes, with the cycle repeating three to six times, or four times.
  • the period and number of cycles used depends on operational performance measured by the effluent quality and the goal to be achieved, i.e. an effluent for hydroponics cultivation or a neutralized effluent to be discharged in the environment.
  • a biogas or gas collection tank is pressurized for use in a combined heat and power system or for direct combustion in a burner.
  • the biowaste is sludge originating from animals selected from a group comprising or consisting of fish, chicken, pigs and cattle.
  • the biowaste is sludge originating from fish.
  • the biowaste is supplemented with other farm waste stream, such as agricultural waste and insect cultivation waste.
  • the system and/or method is used in a recirculating aquaculture system (RAS).
  • RAS recirculating aquaculture system
  • system and/or method are performed in a closed-loop aquaculture system.
  • the invention relates to a use of the system and/or method as defined anywhere herein, for treatment and remineralization of solids and liquid biowaste, especially biowaste from hydroponics and aquaponics plant, or fish plants or fish ponds.
  • Fig. 1 shows a schematic overview of an aspect of the system of the invention.
  • Fig. 2 shows a schematic overview of another aspect of the system of the invention.
  • Fig. 3 shows a representation of the control system health status.
  • Fig. 4 shows a schematic overview of an aspect of the system of the invention.
  • Fig. 5 shows a schematic overview of another aspect of the system of the invention.
  • Fig. 6 shows a schematic view of a settling tank.
  • Fig. 7 shows a schematic view of a first anaerobic digestion tank.
  • Fig. 8 shows a schematic view of a sequential batch reactor.
  • Fig. 9 shows biogas production per liter anaerobic digestion tank over the experimental duration.
  • Fig. 10 and 11 show the methane yield from the experimental reactor based on the amount of carbon present in the fish solids (measured in two different, but related ways).
  • Fig. 12 shows the pH stability over the experiment.
  • Fig. 13 shows the amount of methane in liters produced per liter reactor volume. This is a useful way to see how the methane production may scale with anaerobic digestion tank size.
  • Fig. 14 and 15 show the electricity and energy production estimated as derived per liter reactor (anaerobic digestion tank size).
  • Fig. 16 shows the total biogas volume per liter reactor. It is similar to slide 12 but looking at biogas (methane + CO2 + whatever other trace gases are present) instead of just methane.
  • sludge is meant to be biowaste or wastewater as a slurry of solids in a liquid, such as biowaste or wastewater from a fish plant, or cow or chicken farm.
  • closed-loop aquaculture means an aquaculture production system, whereby solid waste products are collected in some manner typically in the form of a recirculating aquaculture system. It stands in contrast to flow-through or open-loop aquaculture, where incoming water passes through the facility, removing solids downstream or into the surrounding water body.
  • solids means a general term referencing feces, uneaten feed, and miscellaneous waste products, such as mucous, scales, or nonbiodegradable objects, such as bits of netting that are collected by the solids waste treatment processes in aquaculture facilities.
  • settling tank means a vessel that facilitates the settling of solids. A settling step increases the density of the solids and ensures that a consistent concentration of nutrients enters the anaerobic digestion tank.
  • VFAs volatile fatty acids
  • anaerobic digestion tank means any closed system devoid of oxygen that facilitates the decomposition of large molecules e.g., fecal particles into metabolites, such as small molecules mostly consisting of VFAs, as well as gases including methane and carbon dioxide.
  • organic loading rate means an amount of organic matter entering the digestion tank over a given duration.
  • methanogenic digestive microbial community or methanogens refers to archaea and bacteria, which produce methane as an end product. They are highly sensitive to the physiochemical conditions they are grown in, requiring a certain OLR and a lack of oxygen to produce the maximum amount of methane from a given sludge. The process of creating methane is methanogenesis.
  • digestive microbial community refers to archaea and bacteria adapted to facilitate the liberation of nutrients from material, such as a digestate.
  • sulfur redox community refers to bacteria, which facilitate the liberation of nutrients from sludge, such as a digestate, utilizing sulfur as a main component in this process.
  • HRT hydroaulic retention time
  • SRT solids retention time
  • SBR sequential batch reactor
  • mineralization tank or sequential batch tank or aerating tank
  • SBR sequential batch reactor
  • aerating tank means a system that promotes the formation of granules - microbial aggregates, which provide a stable environment for the development of a unique microbial community under alternating anaerobic and microaerophilic conditions.
  • SBR granular communities means the major microbial community of interest in a properly functioning SBR, which are polyphosphate accumulating organisms (PAOs), which solubilize poorly-soluble nutrients, namely phosphorus. SBR granular communities can sequester phosphorus and nitrogen within the granules and release them under specified conditions. They also consume VFAs as their primary food source alongside phosphorus and nitrogen.
  • PEOs polyphosphate accumulating organisms
  • biofouling means the development of a mucous-like bacterial film in the presence of accumulating organic matter. Biofouling can lead to clogging and harbor pathogenic bacteria if left unchecked.
  • trace nutrients means all nutrients required for life but only at very low concentrations. They are generally poorly soluble and thus accumulate in the fish solids in contrast to the filtered water normally delivered directly to a hydroponics system from a recirculating aquaculture system as typically found in aquaponics. As they are bound in the sludge matrix, they are not directly accessible plants in standard aquaponic systems, which rely exclusively on the transfer of the soluble waste stream for plant fertilization.
  • bioavailable means a chemical compound that can be taken up by the target organism for use towards satisfying metabolic needs.
  • tank means any type of vessel or container that can hold a liquid and/or solid.
  • the invention relates to a system for a treatment and remineralization of solids and liquid biowaste.
  • the system as shown in figure 1, 2, 4 and 5 comprises several tanks that are interconnected and together form the system in which the method of the invention can be performed.
  • a settling tank 1 is adapted to receive sludge as biowaste.
  • the biowaste may be provided by a fish tank, animal farm, or organic industrial process, such as paper production or brewing [1], or a chicken farm or originate from cattle or pigs.
  • One or more coagulant may be added to tank 1 to coagulate the solids.
  • the coagulant for this system may be soluble iron, manganese or aluminum or a mixture or salts thereof, such as iron chloride.
  • Filters 9, such as drum filters may precede the settling tank 1 as shown in figures 1, 2, 4 - 6.
  • a membrane m may be present in the tank 1 to redirect solids and a baffle b to prevent a particle up flow.
  • the supernatant may be filtered in a drum filter, whereafter the solids may be entered into tank 1.
  • the filtered supernatant may be returned to a fishpond.
  • the settled liquid may be filtered and returned to the recirculation loop.
  • the settled solids are transferred to one or more anaerobic digestion tank 2, 2a, 2b from the settling tank 1 in the form of concentrated sludge (figure 1, 2 and 4, 5).
  • Tank 2, 2a, 2b comprises mainly an anaerobic digestion microbial community adapted to digest an amount of sludge over a period.
  • Two anaerobic digestion tanks may be used, wherein the first anaerobic digestion tank 2a received sludge from the settling tank 1.
  • This first anaerobic digestion tank 2a comprises or consists of a first anaerobic digestion microbial community, which is a methanogenic digestive microbial community adapted to produce methane from sludge.
  • This digestate may then be transferred to a second anaerobic digestion tank 2b.
  • the second anaerobic digestion microbial community is a sulfur redox community adapted to solubilizing phosphorus.
  • Nutrients nl may be added to the second anaerobic digestion tank comprising sulfur, iron, and a readily bioavailable carbon source.
  • a first and/or second coagulant selected from the group comprising iron, manganese or aluminum or a mixture or salts thereof may be added in the settling tank 1 or in the (second) anaerobic digestion tank.
  • a gas collection tank 4 receives gases formed in the (first) anaerobic digestion tank 2, 2a.
  • the gases may be selected from the group comprising or consisting of methane, carbon dioxide, and trace amounts of other gases, such as nitrogen.
  • the gas mixture can be cleaned, whereafter the gases can be used.
  • Methane can be used to provide energy to the system, carbon dioxide can be used for plant growth.
  • the control system measures and controls the methane:carbon dioxide ratio in the gas collection tank 4.
  • a gas analyzer 4a may be used for the purpose of maintaining an ideal methane: carbon dioxide ratio.
  • the digested sludge is transported from the (second) anaerobic digestion tank 2, 2b to the sequential batch reactor or mineralization tank 3 comprising an aeration supply device 8.
  • oxygen is added to the digested product.
  • Oxygen may be added in repeating cycles of air supply, e.g. 15 to 45, or 20 to 30 minutes air supply interrupted by a 15 to 45, or 20 to 30 minutes settling period. This cycle may be repeated 2 to 6, or 3 to 5, or 4 times. See figures 1, 2, 4, 5 and 8.
  • the sequential batch reactor comprises an oxygen supply device 8 and an aerobic digestive microbial community. After oxygenation in the sequential batch reactor 3, the liquid can be directly discharged to a hydroponic cultivation system or transported to a filtration tank 7 and discharged or the liquid can be transported to a sump tank 5 in a greenhouse. In this tank 5, nutrients may be added to the liquid prior to entering a hydroponic cultivation system.
  • Nutrients n2 may be added to the sequential batch reactor 3 comprising sulfur, iron, and in some instances, a readily bioavailable carbon source.
  • the solids may be collected in a solid collection tank 6.
  • the aerobic digestive microbial community uses an aerated environment to facilitate the liberation of nutrients from the digestate received from the anaerobic digestion tank 2 for the purpose of system goals (use in hydroponics or effluent neutralization).
  • the system comprises a control system for optimizing the output from the anaerobic digestion tank 2.
  • the control system also optimizes the transfer from the first to the second anaerobic digestion tank, the second anaerobic digestion tank to the sequential batch reactor, and the sequential batch reactor to the final system output.
  • the temperature, pH, solid retention time (SRT), organic loading rate (OLR), and dissolved oxygen (DO), and chemical additions (sulfur, iron, readily bioavailable carbon) are constantly measured and adapted in the (first and second) anaerobic digestion tanks and sequential batch reactors (2, 2a, 2b, 3).
  • Figure 3 shows a representation how these parameters can be displayed.
  • the anaerobic and aerobic microbial digestive community in a remineralization pathway will promote three microbial clades in particular: nitrifiers (ammonia oxidising archaea and bacteria, nitrite oxidising bacteria, commamox), sulfur redox bacteria, and phosphate- accumulating organisms (PAOs). These three communities often grow in the form of granules and in biofilm.
  • the anaerobic microorganisms in the (first) anaerobic digestion tank may comprise or consist of acetogens, acidogens, and methanogens.
  • the first two groups break down organic matter into volatile fatty acids (VFAs), and the last group produces methane from the VFAs. Some other bacteria may be present. Methanogens are virtually all archaea, the other two groups are bacteria.
  • the sulfur redox community may comprise or consist of bacteria and facilitates the solubilization of phosphorus.
  • the dominant lifestyle is oligotrophic (meaning: growing in a low carbon environment) and microaerophilic (meaning growing with a low, but constant presence of oxygen).
  • aeration can be intermittently increased (e.g. to 2 mg/L oxygen) leading to nitrification (conversion of ammonia to nitrate).
  • Other nutrients are oxidized, making them more soluble (liberation of nutrients).
  • the phosphate accumulating organisms (PAOs) thrive in this environment, and specifically help sequester or liberate mineral nutrients, such as phosphorus into the water column.
  • the term "liberate” means releasing chemically bound nutrients in the liquid coming from the (second) anaerobic digestion tank 2, 2b (called digestate). All this activity happens in the form of granules. So, there are both aerobic and anaerobic microorganisms present in the SBR, but the contrast to the anaerobic digestion tank is that there is the ability for aerobic lifestyles.
  • phosphorus and nitrogen may be sequestered from the sequential batch reactor 3 and precipitated for example, as struvite or in the form of the granules at the bottom of the tank 3. This can be removed as a solid fertilizer.
  • a biochar filter 7a may be added before discharge.
  • the biochar filter 7a attracts any particles and soluble nitrogen in the liquid and is eventually saturated with nitrogen and no longer able to function as a filter 7a.
  • a filter 7a as a polishing step will lead to period biofilm formation on the filter itself.
  • the effect is more chemical than biological.
  • Steam pretreatment may decrease the total number of functional groups on the filter, while increasing overall aromaticity. These properties will preserv a remaining turbidity and nitrogenous species in the filter 7a, leading to an inmproved neutralization of the effluent compared to excisting systems.
  • the biochar 7a may then be used as a soil alternative or amendment, where it slowly releases nitrogen into the soil, while locking in carbon and promoting soil microbial diversity. This is referred to as biochar-based N fertilizers (BBNFs).
  • BBNFs biochar-based N fertilizers
  • Biochar-based N fertilizers are valuable for soil agriculture as they slowly release nitrogen into the soil while building up organic matter (so there is an economic value in selling the "spent" filter 7a).
  • the filter 7a filters the supernatant from the sequential batch reactor 3 prior to removal of the liquid into the environment.
  • the invention also relates to a method for treatment and remineralization of solids and liquid biowaste.
  • the method can be used in the system described above.
  • the method comprises or consists of the steps listed below.
  • a sludge as biowaste is provided to the first anaerobic digestion tank 2a comprising an anaerobic digestion microbial community adapted to digest an amount of sludge over a period, to establish a methanogenic community.
  • step 2) gas is removed from the first anaerobic digestion tank 2a into a gas collection tank 4,
  • a methanexarbon dioxide ratio in the gas collection tank 4 may be adapted and controlled. This may be done using the control system.
  • a gas analyzer 4a may be used.
  • a step 4) the digestate is provided from the first anaerobic digestion tank 2a to a second anaerobic digestion tank 2b comprising a sulfur redox community and adapted to solubilizing phosphorus,
  • a step 5 the digestate is provided from the second anaerobic digestion tank 2b to the sequential batch reactor 3 comprising a PAO community and adapted to sequestering phosphorus and nitrogen.
  • liquid is removed from the sequential batch reactor 3 for (direct) use in a hydroponic cultivation system, and/or
  • liquid is removed from the sequential batch reactor 3 and transferred to a sump tank 5 to add nutrients to the liquid, prior to use of the liquid in the hydroponic cultivation system, and/or
  • step 6c) liquid is removed from the sequential batch reactor 3 to a filtering tank 7 to remove any residual impurities prior to discharge of the liquid as a neutralized effluent safe to the environment, and/or
  • step 6d) liquid enriched with phosphorus and nitrogen is removed from the sequential batch reactor 3 and is adapted to precipitated as a mineral fertilizer such as struvite,
  • step 7) solids are removed from sequential batch reactor 3 to a solid collection tank 6.
  • the output of the method are constantly optimized by using a control system, to control the output in the anaerobic digestion tanks 2a, 2b, the sequential batch reactor 3, the gas collection tank 4, the solids collection tank 6 and/or the filtering tank 7 by constantly measuring and controlling a temperature, pH, solid retention time (SRT), organic loading rate (OLR), and dissolved oxygen (DO), and chemical additions (sulfur, iron, readily bioavailable carbon).
  • a control system to control the output in the anaerobic digestion tanks 2a, 2b, the sequential batch reactor 3, the gas collection tank 4, the solids collection tank 6 and/or the filtering tank 7 by constantly measuring and controlling a temperature, pH, solid retention time (SRT), organic loading rate (OLR), and dissolved oxygen (DO), and chemical additions (sulfur, iron, readily bioavailable carbon).
  • the main features of the system and method include:
  • o A liquid fertilizerfor facilities connected to a controlled environment agriculture system
  • o A stabilization of downstream hydroponic communities through the dissemination of microorganisms adapted to nutrient remineralization when the liquid stream is used for fertilization
  • o A nitrogen-enriched biochar for facilities targeting a low-nutrient, neutralized effluent that is safe to discharge into adjacent water bodies
  • o A granular microbial biomass fertilizer precipitate produced in both of the above situations. This granular precipitate has a low water content.
  • the 3-stage reactors have a pathogen suppression effect: o
  • the three microbial reactors (first and second anaerobic digestion tank, 2a, 2b, sequential batch reactor 3) each provide a strong selection pressure for their unique communities. This creates the effect of suppressing the transfer of any pathogens from the waste stream to downstream outputs.
  • the STREM control system has the ability to steer the system (constantly) towards efficient operating conditions.
  • user data is fed into a decision-making tree to optimize performance and stability.
  • These parameters reflect the nutritional state as well as the physicochemical state.
  • Further parameters may be added to summarize the production of outputs.
  • the graphics interface can display further information regarding the rate of biogas or electricity production, production over time, and data about the discharge quantities involved in the system. It furthermore serves as an alert system in case there is a perturbation to the system, for example the pH dropping (figure 12).
  • the medium severity levels for solids retention time and anaerobic digestion (AD) nutrient loading may suggest that the feeding rate is too high.
  • the program will decrease the feeding rate into the anaerobic digestion tank 2, then wait to see if this corrects the pH at the next sampling point.
  • STREM both manages and corrects for perturbations to the solids treatments system and can be prioritized for electricity production and hydroponic nutrient solution (low carbon, high nitrogen and phosphorus effluent) or general discharge (low carbon, low nitrogen and phosphorus effluent).
  • the system and method of the invention (STREM) is inserted in the facility at the point of solids capture. In a recirculating aquaculture system this is at the drum filter 9. The majority of water passing through the drum filter returns to the main loop [1], The captured solids are collected in a settling tank 1 [2].
  • a coagulant distribution system provides a coagulant c to the settling tank 1 and facilitates the concentration of the solids [3], Either ferric chloride (Fe 3 Cl3) or magnetite may be used as coagulant.
  • the supernatant of the settling tank 1 can be returned to the drum filter 9 to increase water re-use [4].
  • the concentrated solids are transferred to the anaerobic digestion tank 2 using pumps (P).
  • the tank 2 produces biogas, which is collected on site .
  • the digestate is transferred to a sequential batch reactor 3 for a finishing step (FS).
  • the FS is optimized to create a low- nitrogen effluent (neutralization pathway) or a high-nitrogen effluent (remineralization pathway, depending on the facility demands.
  • the FS requires an air supply device 8 (air compressor).
  • the high-nitrogen effluent can be used as a liquid fertilizer and may be released directly into a downstream hydroponics system.
  • the low-nitrogen effluent is passed through a biochar filtration step in the filtration tank 7, which removes any remaining particles and turbidity as well as sequesters the remaining nitrogen. This creates an effluent suitable for direct discharge into any water body.
  • the biochar may be sold as a soil amendment or regenerated for reuse once it has become enriched with nitrogen.
  • the entire system is regulated by the control system to optimize the production of outputs.
  • the system and method of the invention (STREM) is inserted in the facility at the point of solids capture. In a recirculating aquaculture system this is at the drum filter 9. The majority of water passingthrough the drum filter returns to the main loop [1], The captured solids are collected in a settling tank 1 [2],
  • the supernatant of the settling tank 1 can be returned to the drum filter 9 to increase water re-use.
  • the concentrated solids are transferred to the first anaerobic digestion tank 2a using pumps (P).
  • the first anaerobic digestion tank 2a produces biogas, which is collected on site.
  • the digestate is transferred to a second anaerobic digestion tank 2b.
  • sulfur in the form of sulfate or elemental sulfur may be added, and either ferric chloride or magnetite may provide a source of iron.
  • the digestate is then transferred to a sequential batch reactor 3, which is used to complete the remineralization process and create either the liquid or solid fertilizer, depending on whether the aim is for hydroponics cultivation or discharge into the environment.
  • the system can alternatively create a low nutrient effluent (neutralization pathway) or a high nutrient effluent (remineralization pathway), depending on the facility demands.
  • the SBR requires an air supply device 8 (air compressor).
  • the high- nitrogen effluent can be used as a liquid fertilizer and may be released directly into a downstream hydroponics system.
  • the low-nitrogen effluent is passed through a biochar filtration step in the filtration tank 7, which removes any remaining particles and turbidity as well as sequesters the remaining nitrogen. This creates an effluent suitable for direct discharge into any water body.
  • the biochar may be sold as a soil amendment or regenerated for reuse once it has become enriched with nitrogen.
  • the entire system is regulated by the control system to optimize the production of outputs.
  • the sequential batch reactor When the goal is to use the system in a hydroponics system, the sequential batch reactor is more aerated and less solid biomass (granules) are created. So, the main outputs are the biogas from the anaerobic digestion tank and a liquid fertilizer. When the goal is to produce a neutralized effluent, the sequential batch reactor is less aerated and the outputs are biogas, a solid fertilizer (granules from the sequential batch reactor) and a biochar-based N fertilizer.
  • GUI graphical user interface
  • the data may be implemented manually through a spreadsheet. Later, the data are preferably monitored automatically wherever possible.
  • the GUI will prompt the user whether they are relying on suspended solids or chemical oxygen demand (COD). If the user specifies suspended solids, they will be further prompted depending on the drying method. This may for example be a drying rack with an ability to a dry sample at 100°C as required fortotal solids measurement, or a muffler oven with an ability to a dry sample at 400°C as required for volatile solids measurement. If the user does not have the muffler oven, they will be notified that measurement data may be estimated from the amount of total solids (TS), however the accuracy of the measurement may be lower. If they do not have either option, they will be prompted to send samples to a laboratory for regular analysis.
  • COD chemical oxygen demand
  • wO, wl, w2 correspond to the weighted samples manually measured
  • DF is the di ution factor applied
  • TS and volatile solids (VS) are calculated from those values.
  • the entry "measured value for COD” and DF are manually inputted, TCOD is then calculated from these values.
  • the GUI will prompt the user if they have kits for measuring a total nitrogen, total nitrogen, or total ammonia. Once the user selects one, the parameter control system will adjust calculations to fit the input method. If the user does not have the ability to measure nitrogen, they will be prompted to send samples to the laboratory. A warning message at the bottom may inform the user "Nitrate and ammonia measurement probes are not suitable for solids nitrogen calculations as they measure only dissolved species.”
  • DO represents the dissolved oxygen concentration continuously measured by a DO monitor.
  • the carbon and nitrogen data are used to adjust the nutrient loading rate.
  • the C:N ratio is calculated.
  • a typically C:N ratios may be at least 8 or at least 6 or from 4 to 9, or 4.5 to 8, or 4.5 to 6. The ratio is preferably above 4 or 4.5.
  • the system will adjust the solids retention time and organic loading rate.
  • the solids retention time represents the residency time of a given particle in a tank.
  • the SRT is preferably not higher than 80 days (red zone).
  • the SRT is preferably around from 20 to 25 days (green zone).
  • the period of 25 to 80 days can serve as a fallback period (yellow zone).
  • a change in SRT may be necessary to effectuate due to other parameters, e.g. too high C or N, temperature too low, etc. This is a parameter that the control system will set based on other monitoring information.
  • the C:N ratio is related to a COD:VS ratio. If low-nitrogen organic matter (e.g., leaves, agricultural waste) is added to the anaerobic digestion tank 2 to improve the C:N ratio (increase biogas efficiency), the COD:VS ratio will be changed. This process is called codigestion. A higher COD:VS means there is more organic matter compared to the microbial biomass. The COD:VS ratio may serve as another way to monitor digestion efficiency.
  • low-nitrogen organic matter e.g., leaves, agricultural waste
  • the COD:VS ratio may serve as another way to monitor digestion efficiency.
  • the first anaerobic digestion tank is most critical for temperature control. Depending on the starting temperature of the sludge, some heating may be necessary.
  • the temperature in the first anaerobic digestion tank 2 should preferably not drop below 20°C and is preferably at 28°C or 35°C. Despite insulation, some heating may be required.
  • the control system may show a yellow indicator for a temperature range from 20 to 35°C, and a red indicator if below 20°C. Green indicator may be for a temperature from 1 to 40°C, or > 28°C. Subsequent stages (anaerobic digestion tank2,2a,2b, sequential batch reactor 3) will also have temperature monitoring and regulation, depending on facility needs.
  • the pH is preferably around from 6 to 8.5 or 6.8 to 7.5. Methanogenesis can still be active outside of this range, so yellow indicator zones may include a pH from 6.5 to 6.79, and from 7.5 to 8.5. A red indicator may be shown for zones outside the yellow zones (a pH ⁇ 6.5 and > 8.5).
  • the pH will not be actively controlled and instead only monitored as issues with pH are indicative of other system failures. Subsequent stages (anaerobic digestion tank 2, sequential batch reactor 3) will also have pH monitoring, depending on facility needs.
  • the solids retention time indicates the flow rate into the anaerobic digestion tank 2.
  • the SRT is preferably not higher than 80 days (red zone).
  • the SRT is preferably around from 20 to 25 days (green zone). From 25 to 80 days can serve as a fallback period (yellow zone).
  • a change in SRT may be due to other parameters, e.g. too high C or N, temperature too low, etc. When the SRT is in the yellow zone, the SRT may be decreased.
  • Biogas volume 1 liter biogas per liter of reactor tank 2 volume can be expected (> 1 1 is in the green zone).
  • the yellow zone is from 0.5 to 1 l/l tank2 volume, and the red zone is below 0.5 l/l tank 2 volume (figure 7).
  • CH4 and CO2 are the values provided by the gas analyzer and % CH4 and % CO2 are the calculated percentages of each gas present. In some instances, CH4 and CO2 are the values provided by the gas analyzer and % CH4 and % CO2 are the calculated percentages of each gas present.
  • biogas volume data looks like:
  • Reactor volume is the volume of the anaerobic digestion tank 2
  • Measured volume is the volume of gas produced
  • Days between sampling is the number of days since last measured
  • Adjusted biogas volume is a corrected volume per liter of tank 2
  • CH4 volume present is the rate production of methane produced per liter of tank 2
  • Total CH4 volume produced since last sampling is the total amount of methane produced since the last sampling point. See figures 9, 10, 11, 13 to 16.
  • CH4 and CO2 may be measured by an on-site gas analyzer 4a, which automatically determines the percentages in-line. In this case, the control system will interpret the data and adjust other parameters to prioritize CH4 production.
  • Effluent quality is a parameter summarizing the efficiency of the solids removal system. The exact parameters monitored will depend on the output target (liquid fertilizer or neutralized effluent).
  • a version of an in-line system may rely on measuring the electric conductivity, which is calibrated within the system to relate to a certain nutrient concentration. Otherwise, a hybrid approach is possible whereby facility users will input data on effluent quality into the control system (total solids, nitrogen concentration (total nitrogen or ammonia, nitrate, nitrite)). These measurements are standard in aquaculture facilities and thus do not require additional infrastructure. For the neutralized effluent, phosphorus may additionally be measured to ensure the discharged liquid meets environmental safety requirements.
  • wO, wl, and DF are used to calculate the total solids (TS) as done for the anaerobic digestion tank 2.
  • Nitrate and ammonia are typically monitored in aquaculture systems and may be input manually.
  • Orthophosphate may additionally be monitored to evaluate the remineralization efficiency.
  • the following diagram is an overview of STREM integrated into a RAS.
  • a settling tank 1 From the drum filter, solids are collected in a settling tank 1. The solids are allowed to settle, potentially facilitated by a coagulant dispersal system (optional). If used, a liquid solution containing FeCh may be added daily. A horizontal pipe with holes on the bottom side can be used to remove excess water back into the RAS (returning the water to the drum filter).
  • thermometer and pH sensor monitors temperature and pH, with the heating element adjusted automatically.
  • the temperature is preferably kept around 28 ⁇ 2°C.
  • Biogas is removed from the headspace by internal pressure accumulation; a gas analyzer 4a benefits direct estimation of the methanization efficiency.
  • Pumps P transfer the solids from the settling tank 1 to the anaerobic digestion tank 2 and from the anaerobic digestion tank 2 to the finishing step in the sequential batch reactor 3.
  • the tubing entering the anaerobic digestion tank 2 may add solids into the bottom of the tank, while the tubing removes material from the anaerobic digestion tank 2 preferably from the upper half to prioritize removal of the supernatant.
  • the material is again added to the bottom of the sequential batch reactor 3.
  • Another pump P transfers supernatant from the settling tank 1, preferably near the drainage point at the top to the finishing step, preferably inserted at the bottom of tank 3.
  • a final pump P removes the effluent from the sequential batch reactor 3, preferably from the upper half of the sequential batch reactor tank 3 (figure 8).
  • Aeration is turned on based on the schedule.
  • a valve such as a solenoid valve opens to allow the air to flow into the sequential batch reactor 3, for example via an air stone.
  • the valve closes at the end of the aeration time and the air compressor 8 can be turned off.
  • the wasting/removal tubes are operated by a different pump and may be turned on at a lower frequency independently of the main schedule.
  • Schedule forthe sequential batch reactor may be as described below:
  • an equal volume from the sequential batch reactor 3 may be removed as is added to the start of the system in settling tank 1.
  • Starting on a decantation step may prevent accidental overflows if the schedule is interrupted.
  • the duration will depend on the AD: diluent ratio. If the ratio is 1:1, the decantation time is 2x the feeding time.
  • Stage 2 is the transfer from the anaerobic digestion tank 2 to the aerating tank 3. It may occur before feeding to prevent overflow of the anaerobic digestion tank 2. Feeding the finishing step may occur simultaneously using two pumps.
  • the duration is dependent on the defined SRT, controlling the feeding rate from the settling tank 1 to the anaerobic digestion tank 2. For example, if it takes 15 minutes for the pump to add 100 ml of feed (corresponding to an SRT of 20 days) to a 2 I reactor/tank 2, then the duration of phase 1 is 15 minutes.
  • Stage 4 is an aeration step 5) whereby air may be supplied for 25 minutes, then turned off for 25 minutes - repeated fourtimes. This provides both mixing and provides a minor amount of oxygen to stimulate nitrification. Afterthe final 25-minute pause (final settling step), the cycle may be repeated at stage 1.
  • Biogas collection is the most dependent on system scale.
  • a combined heat and power (CHP) system may be used.
  • Methane pressurizer may be collected from the headspace of anaerobic digestion tank 2.
  • the methane passively collects in a large cylindrical container, which is itself placed inside of a slightly smaller container.
  • the two containers fit snugly enough so that no gas may escape.
  • Vaseline, mineral oil, or a similar viscous gel may help prevent gas leakage.
  • the two containers are located within a cage attached firmly to the ground/ below the containers. As the inner container rises, it pushes against the cage - pressurizing the methane within. The methane then leaves through an exit valve attached to the top of the smaller container.
  • CO2 is 3x heavier than methane, so a higher methane purity will be present at the top of the container and a greater CO2 fraction would be present at the bottom.
  • Methane collection may be done independently of STREM. For smaller facilities it may power a generator inside a greenhouse (to catch CO2 emissions) at a regular schedule.
  • the method comprises the following:
  • an equal volume from the sequential batch reactor 3 may be removed as is added to the start of the system in settling tank 1.
  • Starting on a decantation step may prevent accidental overflows if the schedule is interrupted.
  • Stage 2 is the transfer of sludge from the second anaerobic digestion tank 2b to the sequential batch reactor tank 3 and then the transfer of sludge from the first anaerobic digestion tank 2a to the second anaerobic digestion tank 2b in that order to prevent overflow of the anaerobic digestion tank 2.
  • the duration is dependent on the control system's chosen SRT and OLR, controlling the feeding rate from the settling tank 1 to the first anaerobic digestion tank 2a. For example, if it takes 15 minutes for the pump to add 100 ml of feed (corresponding to an SRT of 20 days) to a 2 L tank 2a, then the duration of phase 1 is 15 minutes.
  • Stage 4 is an aeration step 5) whereby air may be supplied for 25 minutes, then turned off for 25 minutes - repeated fourtimes. This provides both mixing and provides a minor amount of oxygen to stimulate nitrification. Afterthe final 25-minute pause (final settling step), the cycle may be repeated at stage 1.
  • Biogas collection is the most dependent on system scale.
  • a combined heat and power (CHP) system may be used.
  • CHP heat and power
  • methane pressurizer it may be possible to use a methane pressurizer. Methane is collected from the headspace of tank 2a.
  • Biogas collection is the most dependent on system scale.
  • a combined heat and power (CHP) system may be used.
  • Methane may be collected from the headspace of tank 2a.
  • Fig. 14 and 15 showthe electricity and energy production as estimated which could be derived per liter reactor in the anaerobic digestion tank size), in the situation that a combined heat and power system is used for energy generation.

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  • Life Sciences & Earth Sciences (AREA)
  • Microbiology (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Biodiversity & Conservation Biology (AREA)
  • Treatment Of Sludge (AREA)

Abstract

La présente invention propose un système et un procédé complets de traitement et de reminéralisation de déchets biologiques solides et liquides issus des activités d'élevage, incluant l'aquaculture et le bétail. Les principaux composants comprennent un décanteur avec ajout optionnel de coagulant, deux cuves de digestion anaérobie, un réservoir de collecte des gaz, un réacteur séquentiel discontinu doté d'un système d'aération pour l'ajout d'oxygène, une cuve de collecte des solides et une cuve de filtration pour l'élimination et la filtration du surnageant. L'innovation aborde le problème technique de la gestion efficace des déchets biologiques en proposant une solution holistique qui optimise la digestion, la revalorisation des déchets par la production de biogaz et les processus de filtration pour optimiser deux types de production d'engrais avec l'option d'alterner entre un engrais solide et un effluent liquide neutralisé sans danger pour le rejet dans l'environnement, ou un engrais solide et un effluent d'engrais liquide combinés. L'utilisation principale de cette invention réside dans sa capacité à convertir des déchets biologiques en ressources de valeur tout en réduisant à un minimum l'impact environnemental.
PCT/IB2024/055336 2023-06-14 2024-05-31 Système et procédé de traitement des déchets biologiques solides et liquides Pending WO2024256906A1 (fr)

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KR102900774B1 (ko) * 2025-09-24 2025-12-16 주식회사 대종 가축 분뇨를 포함하는 유기성 폐기물 처리 시스템

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