JP2012509170A - Marine sewage treatment - Google Patents

Abstract

A method and system for sewage treatment. The sewage slurry collected in the tank is carried by a macerator pump. The macerated slurry is conveyed to an electrolytic cell to oxidize and sterilize the slurry. Next, the slurry is conveyed to an electrocoagulation tank. Suspension particles are aggregated in an electrocoagulation tank. The agglomerated slurry is conveyed to a first settling tank for separation into sludge and substantially purified supernatant. The supernatant is transferred to a second purification tank to facilitate further separation of sludge. The sludge is discharged to a sludge collection tank. The turbidity level of the discharged sludge is continuously monitored. When the turbidity level is equal to a predetermined low value, sludge discharge stops. The almost purified supernatant is discharged as dechlorinated waste water.
[Selection] Figure 1

Description

  The present invention relates generally to sewage treatment, and more particularly to on-site marine wastewater treatment and purification.

  On-site sewage treatment is generally done in places where access to municipal water treatment plants and similar facilities is restricted. Examples of such places include ships and offshore drilling stations. In such places, sewage usually flows to the holding tank through the installed biological or fermentation unit. Waste water in the holding tank is sent to the sterilization unit when it reaches a certain level.

  The main problems with on-site sewage treatment are biological oxygen demand (BOD), chemical oxygen demand (COD), and particulate matter suspended in water, ie total suspension (TSS). Reduction. Even if the granular material was macerated and decomposed by biological or fermentation type, such reduction of the granular material was minimal with respect to the limit value considering environmental safety. .

  One or more embodiments of the present invention relate to a method and system for treating sewage performed at a ship and / or an installed marine base. In one embodiment of the present invention, a method for treating sewage includes the step of feeding sewage slurry into a sewage recovery tank. Sewage includes raw sewage, black water, gray water, galley waste, and combinations thereof. The sewage slurry further contains suspended particles, organic and inorganic substances, bacteria and entrained gas. The sewage level sensor attached to the sewage recovery tank monitors the sewage level of the sewage recovery tank. When the sewage slurry reaches a preset upper limit level, the sensor triggers an automatic start of operation. When the sewage level falls below a preset lower limit level, the feeding of the sewage slurry may be stopped. The sewage slurry is fed with a macerator pump that macerates the suspended particles. During maceration, the suspension particles are crushed so that the small size particles occupy a larger surface area. The macerated slurry stream may be diverted and returned to the sewage recovery tank. The remainder of the macerated slurry is conveyed by line to the electrolytic cell. The electrolyzer oxidizes or sterilizes the macerated slurry using a controlled amount of seawater or salt water. Since the macerated fine particles occupy a large surface area, the oxidation and sterilization of the macerated slurry in the electrolytic cell is significantly improved. Antifoam is added to the oxidized and sterilized slurry before being piped to the electrocoagulation cell. The sterilized suspension may be agglomerated or agglomerated in an electrocoagulation tank. The agglomerated slurry is transported to the first settling tank and separated into sludge containing agglomerates and substantially purified supernatant. The substantially purified supernatant is conveyed to the second purification tank by a conduit to facilitate further separation of the sludge and the substantially purified supernatant. Sludge from the sedimentation tank and the purification tank settles at the bottom of the tank and is discharged. The turbidity level of the discharged sludge is continuously monitored. When the turbidity level is equal to a preset low value, the valve on the sludge discharge pipe is automatically closed and sludge discharge stops. Substantially purified supernatant may be discharged as treated wastewater.

  The flow of the macerated slurry branched and returned to the sewage recovery tank may be mixed with the sewage slurry in the sewage recovery tank. Thereby, mixing is uniformly maintained in the sewage recovery tank. In one embodiment, a mixing pump may be positioned adjacent to the macerator pump to continuously mix and recirculate the macerated slurry stream with the sewage slurry in the sewage recovery tank.

  A controlled amount of seawater may be mixed into the macerated slurry as the macerated slurry is placed in the electrolytic cell. The amount of seawater placed in the electrolyzer may depend on the inherent treatment capacity of the sewage treatment system at sea. The macerated slurry may be oxidized and sterilized by an electrochemical reaction that occurs in the electrolytic cell. In one embodiment of the invention, the macerated slurry may be contacted with an oxidant in an electrolytic cell.

  The oxidized and sterilized slurry is conveyed to an electrocoagulation tank where the macerated solids and other suspensions are agglomerated. In the electrocoagulation tank, sterilization of sterilized sewage may be enhanced by using metal particles that act as nucleation sites that form coagulation with organic matter. The electrodes in the electrocoagulation tank can be coated with suspensions and lumps when used continuously. In one embodiment of the present invention, the electrocoagulation vessel may periodically undergo an automated air and water purge. In the purge, the particulate impurities coated on the electrode are washed away. The removed product is transported to the first settling tank.

  The nearly purified supernatant may be treated with one or more chemicals before being discharged to neutralize residual chlorine to less than 0.5 mg / L. In one embodiment of the present invention, a suitable amount of reducing agent is injected into the substantially purified supernatant using a metering pump. The reducing agent may be selected from the group consisting of sodium bisulfite, sodium sulfate, sodium thiosulfate and sulfur dioxide.

  In one or more embodiments of the invention, the discharged wastewater is less than 25 mg / mL biological oxygen demand (BOD), less than 35 mg / mL total suspension (TSS), less than 120 mg / L. Chemical oxygen demand (COD) and less than 100 cfu / 100 ml E. coli may be included.

  In another embodiment of the invention, the agglomerated slurry sent from the electrocoagulation vessel, the sludge, and particulate impurities removed during the automated air and water purge are lined to the deaeration chamber. Carried in. Gases generated during the electrolysis reaction and other residual gases released from the slurry are diluted with ambient air and released into the atmosphere. An electric blower may be used to force ambient air into the vent line.

  In another embodiment of the invention, the agglomerated slurry present in the electrocoagulation tank may be discharged to the polymerization tank. One or more cationic polymers may be introduced into the agglomerated slurry to form a solid cluster that has been polymerized into lumps. The polymerized and agglomerated solid clusters may be filtered using a filtration unit.

  In another embodiment of the present invention, a system for treating sewage includes a sewage recovery tank, a macerator pump capable of finely dividing solids suspended in the sewage, a mixing pump adjacent to the macerator pump, an electrolytic cell including a reaction chamber, a reaction An anode disposed in the chamber, a cathode disposed in the reaction chamber, a means for providing power to the electrolytic cell, an electrocoagulation tank fluidly connected to the electrolyzer, a precipitation tank adjacent to the electrocoagulation tank, and a precipitation tank It includes a connected purification tank, a turbidimeter for detecting the turbidity level of the discharged sludge, a dechlorination unit including a drug injection pump or metering pump, and a wastewater discharge pump. In one embodiment of the invention, the precipitation tank is connected to a degassing chamber. The deaeration chamber includes an electric blower and vent means, and is capable of releasing diluted gas generated during electrolysis. In one embodiment of the present invention, a sludge recovery tank is optionally disposed below the settling tank and the purification tank.

  In one embodiment of the present invention, a sewage treatment system includes a rigid base frame that is constructed and arranged to support the weight of the sewage treatment system. In another embodiment of the present invention, the sewage treatment system comprises an air and water purger connected to the electrocoagulation tank. In yet another embodiment of the present invention, a seawater supply source is connected to the electrolytic cell.

FIG. 1 is a flowchart showing a sewage treatment system according to an embodiment of the present invention.

  Each of the appended claims individually defines the invention and for infringement purposes is deemed to include equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the “invention” may in some cases relate only to specific embodiments. In other cases, references to "invention" will be recognized as referring to subject matter recited in one or more claims, but not necessarily all claims.

  Various terms used herein are shown below. For the scope of terms used in the claims that are not defined below, as indicated in the publications and issued patents published at the time of filing, the relevant technical field to which the terms have been given Should be given the broadest definition.

  Embodiments of the present invention relate to a method and system for sewage treatment mounted on a ship and / or an installed offshore platform. As used herein, the term “onboard” refers to (for example, treating water, etc. away from the source, such as a municipal water treatment facility). Ii) It relates to purification in the same facility where sewage is generated.

  FIG. 1 shows a specific example of a system (10) for wastewater treatment mounted on a ship and / or an installed offshore platform, but is not limited thereto. The system (10) includes a sewage recovery tank (12), a macerator pump (14), a mixing pump (13), an electrolysis tank (16), an electrocoagulation tank (18), and a sedimentation tank (22). And a purification tank (24), a dechlorination unit (28) provided with a chemical injection pump (29), and a sewage discharge pump (30). Sewage is treated and purified in a sewage treatment system (10). The sewage treatment system (10) is supported and arranged on a common rigid base (not shown). After purification, the dechlorinated wastewater may be discharged from the ship into open water. In one or more embodiments of the invention, no more than 100 cfu / 100 ml E. coli, no more than 35 mg / ml total suspension, no more than 25 mg / ml biological oxygen demand (BOD) and less than 120 mg / L of chemistry Sewage from which chlorine has been removed, such as having a dynamic oxygen demand (COD), may be discharged. The sea sewage treatment system 10 may have a treatment capacity of 3.0 to 65.0 cubic meters / day. The installation floor space required for the marine sewage treatment system (10) may be small, or the installation area of the system occupied by the marine sewage treatment system (10) may be small. The offshore sewage system (10) may be capable of performing continuous collection and treatment of collected sewage at 24x7. In one embodiment of the present invention, the offshore sewage treatment system (10) can be operated automatically and operator intervention may be limited.

The flow of sewage at sea generally includes raw sewage, waste water, miscellaneous waste water, and combinations thereof. As used herein, the term “waste water” refers to water contaminated with human excreta, including coliforms and other bacteria. As used herein, the term “miscellaneous wastewater” refers to used water, excluding human waste, such as kitchen and shower water. In general, marine sewage is composed of toxic and non-toxic organic and inorganic pollutants, fine suspended and large suspended pollutants including cellulose, sand, sand grains, human biomass and emulsions, and gases. Including. One of the most commonly measured components of sewage is biochemical oxygen demand, or BOD. The amount of oxygen required by microorganisms to degrade organic pollutants is known as biochemical oxygen demand, or BOD. BOD or BOD ₅ for 5 days is a measurement of oxygen consumption by microorganisms for 5 days, and is the most common measure of the amount of biodegradable organic matter in sewage or the strength of sewage. Sewage with a high BOD can deplete the oxygen in the water it receives, killing fish and changing ecosystems.

  On-site sewage treatment is generally done in places where access to municipal water treatment plants and similar facilities is restricted. Examples of such places include ships and offshore drilling stations.

  Referring to FIG. 1, the sewage slurry is conveyed to the sewage recovery tank (12) by a pipe line (50). The sewage recovery tank (12) incorporates a sewage level sensor (not shown) for measuring the sewage level. When the sewage treatment system (10) is set to automatic mode and reaches a predetermined threshold level, the level sensor may automatically start repeating the start and stop of the sewage treatment system. In other embodiments, sewage treatment may be initiated manually.

  When the level sensor detects that sewage in the sewage recovery tank (12) is at a preset upper limit level, sewage slurry may be sent to the flow path (52b) by the macerator pump (14). The macerator pump (14) pulverizes the suspension in the sewage slurry to reduce their particle size. The flow of the macerated slurry is branched (53) and returned to the sewage recovery tank (12). The flow of the macerated slurry is continuously mixed with the sewage slurry in the sewage recovery tank (12) to make the mixture uniform. The mixing pump (13) continuously performs a recirculation treatment (51) on the sewage slurry and the macerated sewage slurry in the sewage recovery tank (12), thereby maintaining the uniformity of the sewage mixture. The

  The remainder of the macerated slurry is conveyed through the assay orifice plate to the electrolytic cell (16) by line (54), oxidized and sterilized to yield a non-hazardous slurry. Thus, the operator need not be exposed to dangerous bacteria such as E. coli. The electrolytic cell (16) may include a reaction chamber, an anode disposed in the reaction chamber, a cathode disposed in the reaction chamber, and means for flowing a direct current between the anode and the cathode. It is contemplated that any electrolytic cell known by those skilled in the art can be used as the electrolytic cell in the examples described herein.

  The macerated slurry may be contacted with an oxidant source in the electrolyzer (16) to sterilize and neutralize E. coli present in the slurry to reduce BOD. Since the macerated particles occupy a larger surface area in the electrolytic cell (16), the oxidation and sterilization effects are significantly improved. In one embodiment of the present invention, the oxidant is generated with seawater or salt water. The oxidizing agent may be generated by passing seawater through the electrolytic cell (16) where the macerated slurry is present. As the macerated slurry is sent (54) through the calibration orifice plate to the electrolyzer (16), a controlled amount of seawater may be mixed with the macerated slurry, instead. A controlled amount of seawater may be separately introduced into the electrolytic cell (16) via a filter or flow controller (not shown). This flow controller limits the flow of seawater to a predetermined value in accordance with the specific treatment capacity of the sewage treatment system (10).

  Seawater may contact the macerated slurry at a ratio of at least about 1: 1. In another embodiment of the invention, brine containing water with sufficient salt to perform electrolysis and form an oxidant is mixed with the macerated slurry. Upon contact with the macerated slurry, the oxidant provides a reaction mixture having a pH of, for example, from about 6 to about 9, or from about 6.5 to about 8.

  The macerated slurry may be oxidized and sterilized by an electrochemical reaction in the electrolytic cell (16). The electrochemical reaction occurs in the electrolytic cell (16) by applying a DC potential to the specially designed anode and cathode plates (electrodes). The macerated slurry conveyed from the macerator pump (14) through the conduit (54) flows between the charged electrodes. Seawater provides sodium chloride and water and acts as an electrolyte for the DC current that flows between the anode and cathode plates. Seawater chloride salts are broken down by electrolysis to form sodium hypochlorite and trace the amount of mixed oxidant. The electrochemical reaction and the resulting oxidant formation kills harmful E. coli bacteria and oxidizes organic compounds in the macerated slurry. Once passed through the electrolytic cell (16), almost 100% of the remaining bacteria are killed and 90-95% of the organic compounds in the sewage can be oxidized.

  Electric power necessary to operate the electrolytic cell (16) is supplied from a DC power source built in the sewage treatment system (10) at sea. In one or more embodiments of the marine sewage treatment system (10), the current in the electrolytic cell (16) takes a certain constant value. The amount of DC current used in the electrolytic cell (16) determines the amount of sodium hypochlorite produced. During electrolysis, small amounts of hydrogen and other gases may be generated as byproducts. The gas is released from or entrained with the oxidized and sterilized slurry.

  In other embodiments of the invention, the oxidant may continue to contact the macerated slurry in a separate container (eg, a conduit or bath (not shown)). The contact time may be set to about 2 minutes, for example.

  The oxidized and sterilized slurry may contain a minimal amount of residual oxidizing agent. In certain embodiments, the oxidized and sterilized slurry may include from about 1 mg / L to about 250 mg / L residual oxidant and residual chlorine.

  In another embodiment of the present invention, the macerated slurry may be oxidized by any method known to those skilled in the art, such as contacting the macerated slurry with ozone in an oxidation bath. . It should be noted that the oxidation in the oxidation tank utilizes a stronger oxidant than that used in the electrolytic cell (16).

  The oxidized and sterilized slurry is conveyed to the electrocoagulation tank (18) by line (56). The oxidized and sterilized slurry undergoes electrocoagulation where the suspended solid particles are aggregated or agglomerated there. Electrocoagulation tanks are known to those skilled in the art and employ various shapes of anodes and cathodes including electrode plates, balls, fluidized bed spheres, wire mesh, rods, and tubes. This electrocoagulation process is based on scientific principles involving the reaction of sewage material to an electrically strongly induced redox reaction. This process can remove more than 99% of the heavy metal cations and also electrocut the microorganisms in the water. It can also precipitate charged colloids and remove significant amounts of other ions, colloids and emulsions.

  The electrocoagulation tank (18) can be used in series with the electrolysis tank (16). In one embodiment, the electrocoagulation vessel (18) may operate in a vertical configuration. As a result, a gas lift that passes through the electrocoagulation tank (18) can be provided while gas is released, thereby reducing fluctuations in flow rate and reducing operating voltage.

  In one embodiment of the present invention, a direct current is introduced into the oxidized and sterilized slurry in the electrocoagulation tank (18) via the electrode plate. The electrode may be made of iron or aluminum. Metal ions are applied to the oxidized and sterilized slurry away from the electrodes. These metal ions can form metal oxides that electromechanically attract the unstable solid particles. If this occurs, the solid can be separated from the supernatant, forming lumped or agglomerated charged entities. Chlorine remaining in the slurry may be electrolyzed in an electrocoagulation tank (18).

  Some solid particles and contaminants can accumulate in the electrocoagulation tank (18) over time. In one embodiment of the present invention, the electrocoagulation tank (18) may be connected to an air purger (17a) and a water purger (17b). The electrocoagulation tank (18) may be cleaned periodically by an automated air purge (57a), water purge (57b), or a combination of air and water purge (57c), and accumulated in the electrode. The contaminants can be washed away. An automated air and water purge combination (57c) is used during each cycle in which the sewage recovery tank (12) is filled or refilled with sewage slurry (50), or the normal sewage treatment system (10). It can be performed between operations. The cleaned contents are conveyed (58) to a degassing chamber (20).

  Before the oxidized and sterilized slurry enters the electrocoagulation tank (18), a small amount of antifoam is added to the oxidized and sterilized slurry (67) and foamed in the first settling tank (22). Can be minimized or eliminated. The antifoaming agent may facilitate gas removal from the agglomerated slurry present in the electrocoagulation tank (18).

  The agglomerated slurry is conveyed to the deaeration chamber (20) by a conduit (58). The degas chamber (20) facilitates removal of the remaining gas using known falling film technology. In one embodiment of the present invention, ambient air is forced into the vent line of the deaeration chamber using a blower (61). This ambient air dilutes the remaining gas and the gas produced during electrolysis. The diluted air is released into the atmosphere (65). The degassed agglomerated slurry enters the sedimentation tank (22), where sludge containing agglomerates will settle or accumulate at the bottom.

  The sludge or agglomerated solids are heavy, so they separate from the nearly purified supernatant and settle to the bottom of the settling tank, and the almost purified supernatant moves upward. The sludge may be discharged (59a) to an optional sludge collection tank (not shown). The substantially purified supernatant may be conveyed (60) to a purification tank (24) fluidly connected to the precipitation tank (22). The almost purified supernatant is further clarified in the purification tank (24). The remaining sludge may be discharged to an optional sludge collection tank (59b).

  Both the precipitation tank (22) and the purification tank (24) have a pair of inclined or conical side walls (22a) (24a). The heavy sludge slides down the side walls (22a) (24a) and accumulates at the bottom of the tanks (22) (24). Both the precipitation tank (22) and the purification tank (24) are further provided with a base port connected to the discharge pipe. These discharge pipes are joined, and a combined or common discharge pipe discharges or removes (59c) aggregate sludge from the settling tank (22) and the purification tank (24).

  Sludge discharge (59c) may be controlled by one or more valves on a common discharge pipe. When the turbidity level of the discharged sludge is equal to a preset optimum low value, the valve may be automatically closed and the sludge discharge (59c) is stopped.

  Returning to FIG. 1, in one embodiment of the present invention, a turbidimeter (26) is attached to a common discharge pipe. The turbidity meter or turbidimeter measures the transparency or turbidity of water. Turbidity is a characteristic of aggregate water due to suspended particles in water. A high concentration of turbidity is recognized as having no cloudiness, turbidity, or water transparency. Turbidity analysis is an optical measurement of scattered light. As light passes through a sample of water, particles on the light path change the direction of the light and scatter the light. If the turbidity is low, most of the light continues to travel in the first direction. With the light scattered by the particles, the particles in the water can be detected. If the turbidimeter (26) attached to the common discharge pipe detects a preset low reading, the valve of the discharge pipe is automatically closed. This further stops sludge discharge (59c). The sludge from the purification tank (24) is mixed with the sludge from the sedimentation tank (22) to form a sewage stream with a total solid content of 2 to 3 wt%. The sewage stream may be removed from the sewage treatment system by a system operator. The almost purified supernatant is discharged as treated or sterilized waste water.

  In another embodiment of the present invention, sludge may be discharged (59c) and collected in a polymerization tank or vessel (not shown). The cationic polymer may be placed in the polymerization tank manually or mechanically. The cationic polymer promotes the dewaterability of the agglomerated sludge and produces one or more large polymer clusters. These large polymer clusters may contain solids in a large proportion of 8% to 25% or more. The polymerized clusters can be dried and can be reduced in weight compared to agglomerated sludge. Advantageously, the volume of sludge consisting of polymerized clusters can be reduced to 75% to reduce costs associated with wastewater treatment and disposal. The polymerization cluster may be filtered with a filtration unit (not shown).

  The filtration unit may comprise a multiple station filtration drying unit. This filtration drying unit is a small unit that easily and safely handles captured particulate waste and can be used in the present situation where multiple equipment parts are required to provide the same result Different from the sewage treatment system. In one embodiment, the multi-station filter drying unit includes a support grid that is shaped to fit a plurality of industry standard filter bags. The one or more steps including introducing the fluid to be processed in the filter bag, dehydrating the fluid, and compressing and drying the weight of the particles are performed by the operation of the multi-station filter drying unit. Performed in-situ. The multi-station filter drying unit is equipped with a dedicated filter bag removal or discharge station, which contains the mass of compressed particles and is dirty and dry to remove the filter bag without liquid . The use of a clear cover and a safety interlock mechanism that operates the cover at the filter bag discharge station regulates the operator's exposure to biohazards, which is inherent in sewage treatment facilities. Dirty or worn filter bags can be removed and replaced with a clean filter bag during operation of the multi-station filter drying unit.

  In other embodiments of the invention, the sludge may be discharged (59c) to a centrifuge unit (not shown). Solid / liquid separation may be achieved using centrifugation followed by filtration without the addition of a polymer that agglomerates the particles. The sludge stream (59c) sent from the settling tank (22) and the purification tank (24) contains massive solids (2 to 3 wt% solids), which are quite heavy and thus from the water further intervening by centrifugation. Separated, two separate streams may be formed: a fluid stream that is relatively free of solids and a sludge that contains more than 10 wt% solids. Solid emissions can be combined with normal waste / garbage without considering biohazard. A special built-in scriber knife may be used to physically remove the solid from the centrifuge and drop it into the container. The container may be provided with a waterproof cardboard for handling. The centrifuge unit may remove solids in a batch mode and may include a recirculation tank that provides a 2-3 wt% feed stream.

  Returning to FIG. 1, the sewage treatment system (10) further includes a dechlorination unit (28). The dechlorination unit (28) includes a drug injection pump or a metering pump (29). The nearly purified supernatant may be dechlorinated (63) by adding an optimal amount of one or more chemicals. In one embodiment, the chlorine content of the substantially purified wastewater can be ensured at a concentration that can meet the requirements of the International Maritime Organization Regulation MPEP 159 (55) for sludge released into the marine environment without further treatment. At a high concentration, sodium bisulfite, sodium sulfite, sodium thiosulfate or sulfur dioxide is poured into the supernatant which has been nearly purified by the metering pump (29). The dechlorinated wastewater will be environmentally safe and the residual chlorine will be almost removed. The dechlorinated wastewater may be gravity drained into the water via a conduit. As shown in FIG. 1, the system (10) may comprise a stainless steel centrifugal submersible pump (30) that discharges dechlorinated wastewater into the water. The discharged wastewater may be less than 100 cfu / 100 ml E. coli, less than 25 mg / L BOD, less than 120 mg / L COD, and less than 35 mg / L TSS.

<Test results>
On-shore testing was conducted at a sewage treatment plant in Katy, Texas. Katy is in the suburbs of Houston. The plant will process 3.2 million gallons per day with a maximum allowance of 13.3 MGD. The marine sewage treatment system has been approved by the International Maritime Organization (IMO) Marine Environment Protection Committee (MPEC) MPEC. Were run under the test protocol and conditions, applying the guidelines for and the modifications applied in MPEC159 (55) of 13 October 2006. All operations of the system were performed by trained technicians. During the 12-day test, proper operation and measurement of the system was performed by the same technician. System operation, experiments and results were certified by an independent third party (in this case, Bureau Veritas).

  Tests were conducted with specific sewage water quality. The influent (“A”) is sewage containing excrement, urine, toilet paper and wash water, with sludge added to the person and hydraulic loading to qualify the sewage treatment plant Sewage with a suitable minimum total suspension concentration was obtained. The tested sewage treatment system was designed for a hydraulic load of 13.6 cu. M / day. The test period was 12 days and all operating conditions were recorded. Samples and operational data were acquired by a sewage treatment system after achieving steady state conditions.

The required quality of sewage was provided from the sewage plant and continuously supplied to the sewage treatment system. 232 samples were processed at predetermined intervals for 12 days, 94 samples were used to measure fecal E. coli concentration, and 138 samples were TSS, BOD ₅ , COD, pH, and chlorine Was used to measure. Fecal E. coli samples were delivered by courier to North Water Laboratory Services, Inc (NWDLS) twice a day at different times and analyzed within 8 hours of sample collection time . Other analytical samples were delivered to NWDLS by courier once a day. NWDLS is certified by the United States Environmental Protection Agency (EPA) and is certified by the National Environmental Research Institute certification program and the Texas Committee environmental standards.

In all tests, the influent meets the resolution requirements of MPEP.159 (55). As shown in Table 1 below, the geometric mean of TSS was 888.6 mg / L and the minimum value for all 12-day tests was 618.0 mg / L.

After treating sewage according to the method of one or more of the examples described above, demineralized waste water ("B") was tested. The wastewater met the requirements of the resolution of MPEP.159 (55). This drainage means drainage into water in the sewage treatment process. As shown in Table 2 below, the geometric mean value of fecal E. coli was 8.7 colony forming units per 100 ml, which was sufficiently lower than the required geometric mean value of 100. Other analyzes of the drainage system are also shown in Table 2, the geometric mean of TSS is 16.3 mg / L, COD value is 30.3 mg / L, BOD5 value is 7.5 mg / L, pH is 7.0 within the range of 6.1 to 7.7. Chlorine was confirmed to have a range of 0.01 to 0.40. These results meet the criteria of MPEC.159 (55).

  Although not shown herein, the sewage flow may be altered based on system optimization as long as it is modified in accordance with the spirit of the invention as defined in the claims. Devices such as pumps, tubes, or additional electrolytic cells or filtration units may be added through the processes described herein.

  The embodiments described herein are contemplated for use in offshore facilities such as ships, for example, ships and bases. For many commercial applications, it is generally difficult to install a sewage treatment system in a small area such as in an offshore facility, if not impossible. However, the embodiments of the present invention further provide a purification system with a small footprint and overall size, thus mitigating installation problems.

  While the above description of embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The basic scope of the invention is defined in the appended claims. The present invention is not limited to the embodiments, versions, or specific examples described, but is an invention that can be implemented and used by those skilled in the art when the information herein combines the information and techniques available. Is included.

Claims (20)

A method for treating sewage at sea, the method comprising:
Carrying a sewage slurry containing suspended particles, organic and inorganic matter, bacteria and entrained gas to a sewage recovery tank;
In response to a sewage treatment level sensor that detects a preset upper limit level of the slurry in the sewage recovery tank, and automatically starting the conveyance of the slurry using a macerator pump that macerates the slurry; and
Carrying the macerated slurry to an electrolytic cell;
Oxidizing and sterilizing the macerated slurry carried to the electrolytic cell;
Adding an antifoaming agent to the oxidized and sterilized slurry before carrying the slurry to an electrocoagulation vessel;
Promoting aggregation of particles suspended in an oxidized and sterilized slurry in an electrocoagulation vessel;
Transporting the agglomerated slurry to a first settling tank and separating it into agglomerated sludge and a substantially purified supernatant;
Transporting the substantially purified supernatant to a second purification tank to facilitate further separation of the sludge and the substantially purified supernatant;
Removing the sludge through the base port of the precipitation tank and the purification tank;
Continuously measuring the turbidity level of the removed sludge and automatically stopping the removal of the sludge when the state of the removed sludge is equal to a preset value;
A method for treating marine sewage, comprising a step of discharging the substantially purified supernatant from the purification tank as treated wastewater. Further comprising branching the macerated slurry stream to a sewage recovery tank;
The method of claim 1, wherein the macerated slurry stream is continuously mixed with the sewage slurry in the sewage recovery tank to maintain uniform mixing of the sewage.   The method of claim 1, further comprising contacting the remaining macerated slurry with a controlled amount of oxidant in an electrolytic cell.   4. The method of claim 3, wherein the oxidant is generated from seawater or salt water.   The electrocoagulation tank further includes the step of being automated and periodically subjected to a combined air and water purge, the purge comprising particulate contaminants accumulated on one or more electrodes in the electrocoagulation tank. The method according to claim 1, wherein   The method of claim 1, further comprising discharging the treated wastewater out of the ship.   7. The method of claim 6, further comprising injecting one or more chemicals before neutralizing the treated waste water to neutralize residual chlorine to less than 0.5 mg / L.   8. The method of claim 7, wherein the drained effluent has a biological oxygen demand (BOD) of less than 25 mg / L.   8. The method of claim 7, wherein the drained effluent has a total suspension (TSS) of less than 35 mg / L.   8. The method of claim 7, wherein the discharged waste water has a chemical oxygen demand (COD) of 120 mg / L.   The method according to claim 7, wherein the discharged waste water has coliforms of less than 100 cfu / 100 ml.   The method of claim 1, further comprising the step of conveying the agglomerated slurry to a degassing chamber to facilitate degassing of entrained gas.   8. The method of claim 7, further comprising controlling the administration of chemicals injected into the treated waste water.   The method of claim 12, further comprising diluting the entrained gas of the agglomerated slurry with outside air.   13. The method of claim 12, further comprising treating the sludge at sea.   The method according to claim 12, wherein the macerator pump pulverizes solid particles suspended in the sewage slurry to promote sterilization in the electrolytic cell. Marine sewage treatment system
A sewage recovery tank;
A macerator pump connected to the sewage recovery tank;
A mixing pump adjacent to the macerator pump and connected to the sewage recovery tank;
An electrolyzer configured to receive the macerated sewage from the macerator pump;
An electrocoagulation tank adjacent to the electrolytic cell;
A deaeration chamber connected to the electrocoagulation tank by conduit means;
A first settling tank adjacent to the degassing chamber;
A second purification tank fluidly connected to the first precipitation tank;
A turbidity meter installed in a common sludge discharge line connected to both the sedimentation tank and the purification tank;
A dechlorination unit including a drug infusion pump;
A drainage discharge pump,
Each of the sedimentation tank and the purification tank is a marine wastewater treatment system including a pair of conical side walls and at least one base port for removing sludge.   The system of claim 17, further comprising an air and water purger coupled to the electrocoagulation vessel.   The system of claim 18, further comprising a seawater source connected to the electrolyzer.   The system according to claim 19, wherein the deaeration chamber further comprises air blowing and exhausting means for releasing gas generated during electrolysis to the atmosphere.

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