Classifications

• • 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
  • C02F3/02—Aerobic processes
  • C02F3/12—Activated sludge processes
  • C02F3/1205—Particular type of activated sludge processes
  • C02F3/1215—Combinations of activated sludge treatment with precipitation, flocculation, coagulation and separation of phosphates
• • 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
  • C02F3/22—Activated sludge processes using circulation pipes
  • C02F3/226—"Deep shaft" processes
• • 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
  • C02F3/30—Aerobic and anaerobic processes
  • C02F3/308—Biological phosphorus removal
• • 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
  • C02F2209/005—Processes using a programmable logic controller [PLC]
• • 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
  • C02F2209/44—Time
• • 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
  • C02F3/30—Aerobic and anaerobic processes
  • C02F3/302—Nitrification and denitrification treatment
  • C02F3/305—Nitrification and denitrification treatment characterised by the denitrification
• • 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
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W10/00—Technologies for wastewater treatment
  • Y02W10/10—Biological treatment of water, waste water, or sewage

Definitions

• the invention relates to a method for biologic purification, the method being based on purification of a fluid to be processed, such as waste water, by means of an activated sludge process that operates at least partly on batch principle, in which aeration of the liquid to be processed, separation of clean liquid and removal of purified liquid take place in successive phases in a same processing space.
• Liquid to be processed is fed into a process space containing a mass of activated sludge, whereby the mass of activated sludge therein is aerated at least from below by aeration air, being led thereto via a flow assembly by means of an air distribution assembly, existing essentially in connection with a bottom of the process space, in order to purify the liquid to be processed by oxidizing microorganisms in the mass of activated sludge, the organisms using impurities in the liquid to be processed as nutriment thereof.
• the method described above has been applied for e.g. in HKN-waste water purification plants developed and marketed by engineering office Ekora Oy.
• waste waters are being purified mechanically, chemically, biologically or by combinations of the above depending on the quality of the waste waters.
• different kinds of membrane techniques are being used.
• Waste waters of exceptionally difficult nature can also be treated on evaporation principle.
• major part of purification demand is, however, aimed at treatment of domestic sewage.
• waste waters are of biologic origin, which is why it is also profitable to purify the same biologically.
• waste waters in food industry are being purified on the same principle, which is the case also with the waste waters e.g. in wood industry.
• activated sludge method means simply aeration of waste water or in other words feeding oxygen to microorganism, which for their part use impurities (nutrients) in the waste water as nutriment thereof.
• a purification plant operating on activated sludge method can be carried out techically e.g. in two ways.
• the first alternative is based on a continuous aeration taking place in an aeration tank, from which a mixture of waste water and activated sludge flows into a secondary settling tank. Activated sludge gets pumped from the secondary settling tank in a sedimented state back to the aeration tank and clarified water flows out in purified state from the upper part of the secondary settling tank.
• the second alternative is based on the idea that the whole mass of activated sludge is simultaneously in an aeration tank, in which waste waters are being fed. In this case there doesn't exist, however, any separate secondary settling tank, but instead the aeration tank in question acts also as a settling tank after the aeration therein has been stopped. When an adequate amount of activated sludge has settled, a clarified upper layer or in other words purified waste water can be led out from the plant
• a batch process being based on a normal activated sludge method, has, however, a number of disadvantages, which have retarded its complete breakthrough e.g. with a view to different kinds of waste water flow circumstances, malfunctioning phases, narrow installation sites, but also partly due to investment costs thereof.
• a batch process can first of all normally receive only an amount of waste water for which it is programmed and dimensioned. E.g. a sudden peak consumption leads to overflow, which means letting out only partly purified waste water from the purification plant. Avoiding overflow requires extra balancing tanks and auxilliary apparatuses causing thus additional costs.
• the method according to the invention is mainly characterized by that separation of liquid that has been purified in the process from the activated sludge and removal of the liquid from the process space is being carried out by leading the liquid from below, at least when the aeration taking place from below is interrupted, through the mass of activated sludge and a filter assembly existing in connection therewith.
• the volume of the actual process space can be dimensioned in a fractional part, e.g. approximately 1/5 - 1/10 of present tanks that are based on a clarification taking place from above. Because removal of water takes place through the filter assembly, on a discharge line there are never bigger particles to be found than fine particles.
• advantageous embodiment of the method also denitrification and biologic reduction of phosphorus are possible in a way that e.g. not any chemical coagulants are needed.
• Functioning of a process operating on the method according to the invention takes places in an extremely simple manner and efficiently as an advantageous embodiment by monitoring height of the fluid surface in the process tank, which offers a number of advantages with a view to controlling of the process and its functioning in practice.
• the method it is possible to follow even high alterations in the hydraulic load in a fluent manner by switching on the phases of internal recycling and removal of purified waste water in a surface guided manner with optimum periods.
• there may not occur any overflow as is the case in a traditional batch purification plant, when a process tank thereof is already fulfilled.
• Also possible malfunctioning situations of the process do not worsen the quality of discharged water as easily as in present arrangements, either.
• the invention enables furthermore device techniques as simple as possible, whereby among other things a usual discharge pump may not necessarily be needed.
• An apparatus operating on the method according to the invention has a good mechanical operating reliability minimizing thus the need for service and maintenance, in addition to which those smaller total dimensions enabled by the invention bring about economical savings.
• the invention relates to a method for biologic purification, the method being based on purification of a fluid to be processed, such as waste water, by means of an activated sludge process that operates at least partly on batch principle, in which aeration of the liquid to be processed, separation of clean liquid and removal of purified liquid take place in successive phases in a same processing space.
• Liquid to be processed is fed into a process space 1 containing a mass of activated sludge M, whereby the mass of activated sludge therein is aerated at least from below by aeration air, being led thereto via a flow assembly 2 by means of an air distribution assembly 3, existing essentially in connection with a bottom of the process space, in order to purify the liquid to be processed by oxidizing microorganisms in the mass of activated sludge, the organisms using impurities in the liquid to be processed as nutriment thereof.
• Separation of liquid that has been purified in the process from the activated sludge and removal of the liquid from the process space 1 is being carried out by leading the liquid from below, at least when the aeration taking place from below is interrupted, through the mass of activated sludge M and a filter assembly 4 existing in connection therewith.
• the method comprises a balancing and recirculation phase I, II, whereby liquid surface in the process space 1 is first of all allowed to get balanced by gravity on the principle of communicating vessels by means of a flow v taking place through the filter assembly 4 and the air distribution assembly 3 into a balancing space 5 acting as the flow assembly 2 or a part thereof, whereafter recirculation w of the liquid that has been filtered in the balancing space into the process space 1 is initiated in order to increase solid matter quantity (MLSS) of . the mass of activated sludge M by relayering the same.
• MMS solid matter quantity
• aeration of the mass of activated sludge M is being maintained while the liquid to be processed is fed into the process space 1, that the aeration is being interrupted before initiating of the balancing phase I and, that the aeration is restarted before initiating of the recirculation phase II.
• height of the liquid surface in the process space 1 is being monitored by monitoring means 15, such as by a float controlled 15b control unit 15a as shown e.g. in figure Ia, in order to initiate the balancing phase I when the liquid surface in the process space has reached an upper limit, being set for the same.
• monitoring means 15 such as by a float controlled 15b control unit 15a as shown e.g. in figure Ia
• an exhaustion phase of the purified liquid is being initiated in a preferably adjustable time after the recirculation phase II has ended, and stopped when the liquid surface in the process space 1 reaches a lower limit, being set for the same.
• the liquid when feeding of the liquid to be treated into the process space 1 is interrupted, the liquid is being stored on the principle shown e.g. in figure 2a temporarily in a buffer space x existing in connection with the process space 1.
• the recirculation w of the recirculation phase II is being carried out on Mammut-principle, by bringing aeration air by means of the flow assembly 2, such as a flow channel 2; 2a or 2; 2b, according to figure Ia being external to the balancing space 5 or being according to figure Ib placed internally therein, or in a corresponding manner to a lower part of the balancing space 5, at a distance e from the bottom of the process space 1, and/or by a separate circulation pump 6, being coupled with the flow assembly 2.
• the method according to the invention advantageously further, it comprises a denitrification phase and/or a phase for biologic reduction of phosphorus, during which the liquid to be processed is being brought to the process space 1 while the aeration is interrupted, in order to carry out in an anaerobic state reduction of nitrogen, which is followed by a shutdown phase, the length of which is preferably adjustable, or alternatively performed phase/phases for recirculation of the liquid to be processed and aeration, in order to carry out in an anoxic state biologic reduction of phosphorus, whereafter when needed a shutdown phase is to follow, the length of which is preferably adjustable.
• oxygen and/or nitrogen content of the liquid to be processed is monitored particularly in order to control the process during the denitrification phase and/or the phase for biologic reduction of phosphorus .
• MLSS may be significantly higher than in a traditional clarification-sedimentation process. This leads to a high space load and by virtue thereof to a "not seen before” decreasing of the volume of the aeration tank:
• waste water flows freely or gets pumped z into an aeration tank 1, in which aeration is running.
• a compressor C feeds air e.g. in the implementation shown in figure Ib at the lower part of the center pipe 2; 2b, but not totally at the bottom.
• Electrically controlled valves V2 and V3 in the upper part of the center pipe are closed.
• Aeration air is distributed through hole pipes 3 e.g. of drain pipe-type evenly on the whole bottom, whereby e.g. in larger scale use a filter gravel layer, such as e.g. an underdrain filtration sand layer is used as the filter assembly 4, or in smaller implementations e.g. removable tray filtration discs.
• the load of activated sludge SL may be according to experience e.g. 0,08 [kg BHK 7 / kg MLSS x d) , which means the biologic need for oxygen of the entering waste water in relation to the total amount of activated sludge.
• the volume of the aeration tank can be reduced significantly, if the consistency of the activated sludge (MLSS) is allowed to grow. In the method this situation is thus being taken advantage of.
• a surface height relay stops the aeration compressor C.
• the waste water liquid rises v slowly through the bottom filter 4 into the center pipe, while the main part of solid substance remains in the filter 4 (which acted in the previous phase as an aerator) .
• the logic center opens the recycling valve V2 and the compressor C starts to run simultaneously.
• the center pipe 2b along with its air feed operation changes into an air pump (so called Mammut-pump) , thus starting to pump aerated waste water through the recycling valve V2 as a recycling flow w taking place from above into the aeration tank 1.
• Suction flow through the bottom filter 4 follows the flow equation
• the activated sludge getting settled and sedimented forms continuously additional layers, which is why the solid matter content of the waste water discharged from the aeration tank decreases.
• the logic relay opens furthermore the actual discharge valve V3, in which connection the recirculation water valve V2 gets closed.
• the exhaustion phase of the purified liquid is thus taking place, which lasts till the surface height relay notices the lower limit and closes the discharge valve V3.
• the compressor C is running all the time, in which case the direction of the air flow is changed at the same time to take place through the bottom filter 4, which acted in the previous phase as a filter, the air flow giving thus aeration air to the aeration tank 1.
• This aeration air also refreshes and flushes the bottom filter 4, which operates in this phase thus alternatively as an aerator.
• the aeration taking place from above occurs by feeding the recirculation flow w advantageously by one or several elongated hole or nozzle pipes JP at a wider area on the liquid surface in the process space or above the same.
• an auxilliary aerator such as e.g. a so called turbine aerator D, which is being used on the filter surface in order to bring about additional aeration efficiency when needed by its own rotating motor aided by a compressor air feed or either without the compressor air feed.
• a separate circulation pump 6 being exploited therewith, there has been exploited extra valves V4 and V5 in order to carry out desired flow operations in cooperation with the main actuator valves V2, V3.
• Valve arrangements of corresponding type can naturally be exploited also in those implementations e.g. according to figures Ia-Ic when a separate recirculation pump is being exploited.
• the process operations are complemented by a pump tank X, thanks to which the waste water feed pump has storing and waiting capacity for the whole time that the internal balancing I, recirculation II and discharge pumping phases described above are running.
• the operating periods or in other words e.g. a difference of the surface level relay can be adjusted suitably.
• the number of periods e.g. per day is thus defined.
• a process being carried out according to the invention belongs in a way into the circle of SBR-techniques, being an intermediate form of the batch techniques and the continuously operating system.
• an extra time period can also be applied by a logic relay, in which case with a special timing, denitrification (complete removal of nitrogen) and biologic removal of phosphorus are possible. Computing of the amount of waste water is also possible by pulse computing.
• controlling of the process is not necessarily bound to time, but instead the controlling takes place on grounds of the height of the surface in the aeration tank, this has to be taken into account in the operation logic.
• the aeration can be interrupted. The length of the interruption period depends on the conformities of law of the bio process.
• the surface rises which means that new waste water is flowing in, the aeration starts immediately.
• the described situation is advantageous particularly for the denitrification phenomenon and also for the biologic removal of phosphorus.
• the requirements for denitrification exist with a correct load for the activated sludge SL and dimensioning for the aeration.
• the oxygen content in the exhaust suction phase must be brought down to 0-level. This is carried out so that the compressor C is stopped when the waste water is getting pumped in and the length of the shutdown time will be adjusted suitably as learnt by experience.
• the biologic reduction of phosphorus is based on the ability of certain bacteria, such as those belonging to Acinetobacter-family, to bind with themselves under aerobic circumstances a large amount of phosphorus and to release the same under anaerobic circumstances.
• the biologic reduction of phosphorus requires a treatment period for waste water, in which water does not contain soluble oxygen nor nitrogen oxide (anoxic state) . There has to be an adequate amount of nutrients available also.
• the invention is not limited to the embodiments presented or described above, but instead it can be varied within the basic idea of the invention in very many ways. It is thus clear that the method according to the invention can be varied by very many parts thereof by using filtration and flow arrangements, the types of which differ structurally from each other. It is furthermore possible to complement the method according to the invention by complementive control probes, measuring logics and activators, such as control valves, back-pressure valves etc with a view to fine adjustment of the process control. Furthermore in connection with the method, it is possible to exploit shutdown or waiting periods to be adjusted as needed also between its separate process phases, in order to stabilize the process in the process space. Furthermore it is possible to exploit a technique known as such for chemical reduction of phosphorus e.g.

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• Life Sciences & Earth Sciences (AREA)
• Biodiversity & Conservation Biology (AREA)
• Chemical & Material Sciences (AREA)
• Water Supply & Treatment (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Hydrology & Water Resources (AREA)
• Microbiology (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Molecular Biology (AREA)
• Analytical Chemistry (AREA)
• Purification Treatments By Anaerobic Or Anaerobic And Aerobic Bacteria Or Animals (AREA)
• Activated Sludge Processes (AREA)

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• 2009
  • 2009-07-17 FI FI20095795A patent/FI121506B/fi not_active IP Right Cessation
• 2010
  • 2010-06-15 WO PCT/FI2010/050501 patent/WO2011007045A1/en active Application Filing
  • 2010-06-15 RU RU2012103445/04A patent/RU2565063C2/ru not_active IP Right Cessation
  • 2010-06-15 EP EP10799478.2A patent/EP2454202A4/en not_active Withdrawn

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