BR112019009117B1 - WASTEWATER TREATMENT SYSTEM AND METHOD BY MEANS OF IMPROVED ELECTROFLOTATION - Google Patents

Abstract

SYSTEM AND METHOD OF WASTEWATER TREATMENT BY MEANS OF ENHANCED ELECTROFLOTATION A method of wastewater treatment involves the electrolysis of a mixed stream of seawater and wastewater within one or more electrolytic cells mounted outside a batch tank. The electrolytic flow is channeled to a suppression chamber that is mounted above the batch tank. A diluted polymer solution is injected upstream from an in-line mixing pipe into the suppression chamber virtually simultaneously with the electrolytic flow. The polymer solution and electrolyzed stream are dispersed as a fine shower over the residual seawater and wastewater in the batch tank. The polymer solution facilitates the flocculation of suspended solid particles and creates a distinct floating layer of flocculated solid particles linked to microbubbles. A substantially clarified effluent is separated from the flocculated layer and neutralized before discharge. The flocculated layer is pumped from the batch tank to a drying system where the entrained solids are compacted to a desired level. A concentrate generated during the solids/sludge drying stage is recirculated to the tank (...).

Description

TECHNICAL FIELD

[0001] The present invention concerns the treatment of wastewater and, in particular, the oxidation and removal of contaminants from wastewater, including suspended solids, organic matters, heavy metals and bacteria using the mechanically induced electroflotation method.

HISTORIC

[0002] There are some conventional processes used to remove solids/impurities suspended in water. However, each of these processes has associated disadvantages, as described below.

[0003] Dissolved Air Flotation (DAF) is a treatment process that clarifies water by removing suspended matter, such as oils and greases or solids. Removal is accomplished by dissolving air in the wastewater under pressure, using an external compressed air source or an air source from a blower unit, and then releasing the air at atmospheric pressure into a flotation tank basin. The released air forms microbubbles that adhere to the suspended matter in the wastewater, causing the suspended matter to float to the surface of the water, where it can then be removed by a mechanical skimming device. However, it is difficult to produce the ideal fine bubble size (bubble flow) to float suspended matter effectively without the presence of specialized and expensive diffusers and high-pressure air feeders. Additionally, as bubble diffusers mounted on the bottom of a DAF tank cannot provide 100% coverage of the tank surface area, this allows portions of the wastewater to be diverted from the DAF flotation process without being treated. Therefore, as the mass of floating solids remains on the surface of the water, mechanical skimming devices or pumps are required to effectively remove the solids from the tank. Although the DAF is more mechanically intensive, it is not suitable for locations such as offshore drilling rigs, where equipment maintenance is susceptible to neglect.

[0004] Electroflotation (EF), which involves floating by electrically generated bubbles, is another process for removing floating ions or solids, suspended or dissolved in the liquid phase. EF requires a cathode (which can be made from a non-oxidizing material) and an anode (which can be made from iron or aluminum). Electrode plates or packages can be connected to an electrical power source and positioned within a flotation tank beneath the water surface. During electrolysis, the electrode plates or packages generate small bubbles of gas (e.g., O2, H2) that are then bound to pollutants (e.g., suspended solids) in the water before they begin to float on a flotation tank where they can be more easily collected and removed. However, to produce the correct bubble size requires certain control of the electrical power on the submerged electrode plates/packages. The traditional EF process has the disadvantage of requiring continuous maintenance due to the layer of iron or aluminum hydrates and oxides that forms on the surface of the electrodes, without separating from them, so that over time the electric current decreases and therefore also decreases the formation of hydrates. Another disadvantage is that the electrodes are subject to irregular wear, requiring frequent replacement before they are completely worn out. Additionally, maintenance of the electrode plates/packages requires both draining the flotation tank and removing the electrodes from the service water volume. As the electrode plates/packages mounted on the bottom of the tank often do not produce 100% coverage of the tank's water surface, this allows parts of the wastewater to end up bypassing the flotation process, therefore leaving the process unit. no treatment. Therefore, as the mass of floating solids remains at the surface of the water column, similar to the DAF process, mechanical skimming devices or pumps are required to effectively remove the solids from the tank.

[0005] For these reasons, the wastewater treatment industry, especially the marine sewage treatment industry, requires a technically and economically viable system for the efficient separation of solids, organic products and removal of bacteria.

SUMMARY OF THE INVENTION

[0006] According to one or more embodiments, the invention relates to a wastewater treatment system and method. In one embodiment, the invention relates to a method of treating wastewater or marine wastewater.

[0007] According to one embodiment, a wastewater treatment system (or "treatment system") is comprised of a main metering sewage treatment tank with level control system, a locally mounted electrical control panel, one or more highly efficient electrolytic cells, a blower for hydrogen dilution and an automatic polymer agitation/mixing system on a sliding platform. The treatment system also includes a dechlorination unit consisting of a bulk sodium sulfite/bisulfide storage/dechlorination (neutralization) reservoir and a chemical injection pump. The dechlorination unit ensures that chlorine-free effluent compliant with the International Maritime Organization (IMO) is discharged into the sea. The treatment system's treatment capacities range from 4.85 to 49.95 cubic meters per day, using a small physical installation space. In one aspect, the treatment system is used in marine and offshore installations that require permanent or long-term operation for the treatment of marine sewage.

[0008] The treatment system is designed to operate in automatic mode with minimal operator intervention. Based on the sewage treatment demand of the platform or vessel, the treatment system initializes the sewage transfer and begins treatment processing. A manual operating mode is provided for diagnosis and troubleshooting and emergency pumping and/or flushing of the treatment system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The invention will be described in more detail below and with reference to the accompanying drawings, all of which describe or relate to apparatus, systems and methods of the present invention. In figures, not drawn to scale, each similar component illustrated in multiple figures is represented by a similar number. In the figures:

[0010] Figures 1A and 1B illustrate multiple views of an exemplary wastewater treatment system according to one configuration.

[0011] Figure 2A illustrates an electrolytic cell according to one configuration.

[0012] Figure 2B illustrates an electrolytic cell according to another configuration.

[0013] Figures 3A and 3B illustrate multiple views of an exemplary polymer mixing system according to one configuration.

[0014] Figure 4 illustrates a block diagram of an exemplary wastewater treatment system according to one configuration.

[0015] Figure 5 illustrates a block diagram of an exemplary system for drying sludge generated from wastewater treatment for landfill disposal according to one configuration.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Depending on the context, all references below to "invention" may, in some cases, refer only to certain specific configurations. In other cases, it will be recognized that references to the "invention" will refer to the subject matter cited in one or more, but not necessarily all, of the claims.

[0017] In one embodiment, the present invention relates to a system 100 for treating wastewater or marine wastewater containing suspended solids and other impurities (e.g., organic matter, bacteria, etc.). System 100 is a batch treatment system that uses electrolytic cells to generate an efficient oxidant/microbubbles and uses polymers as a flocculating agent to create a "floating layer" of suspended solids that is effectively removed from the system at the end of each cycle. of treatment.

[0018] The term "wastewater" as used herein includes any water to be treated, such as black water and gray water from offshore platforms and marine vessels, or a stream of wastewater from industrial, agricultural and municipal/residential sources, containing pollutants solids of biodegradable material. Marine wastewater streams generally include black water, gray water, and combinations thereof. The term "black water" refers to water contaminated with human waste that includes coliforms and other bacilli. The term "gray water" refers to used water absent of human waste, such as water from kitchens, laundry, sinks and showers. Generally, marine wastewater is composed of toxic and non-toxic organic and inorganic contaminants, micro and macro suspended solid contaminants, including cellulose, sand, granulate, human biomass, emulsions and gases. The pollution potential of black water and gray water combined is indicated by several wastewater parameters, the main ones being: biochemical oxygen demand (BOD), chemical oxygen demand (COD), coliform bacteria and suspended solids (SS). . TSS can be organic in nature and can serve as a safe haven for bacteria and other harmful microorganisms. The terms "wastewater", "sewage" and "marine wastewater" are used interchangeably in this document.

[0019] In another configuration, the invention relates to a method and/or cycle of wastewater treatment. The method involves electrolysis and an enhanced/mechanically induced electroflotation stage to efficiently separate suspended solids and clarify water. In a first step, an electrolytic cell can be used to generate disinfectant (e.g. sodium hypochlorite) that helps to oxidize organic matter and create microbubbles (hydrogen/oxygen). These bubbles are capable of suspending any solid matter in suspension in the water volume of a batch tank. In a second step, a small amount of polymer can be mixed in-situ within a mixing cylinder of the piping in the system. The process flow through the mixing coil ensures good dispersion of the mixed polymer in the wastewater stream. The polymer added together with the microbubbles from the first step creates an electroflotation condition to facilitate solid agglomeration and floating on the liquid surface. The method further involves the treatment of wet polymerized solid waste/sludge generated during the treatment process to obtain a concentrated and compacted sludge for landfill disposal. The center can be used to supplement seawater or reduce the volume of seawater used during a subsequent wastewater treatment cycle.

[0020] FIG. 1A and FIG. 1B illustrate multiple views of a specific, non-limiting configuration, exemplifying a system 100 for treating wastewater. System 100 includes a single batch tank 105 used to receive wastewater to be treated. Batch tank 105 is also designed to contain seawater that must be mixed with wastewater. In an exemplary configuration, the batch 105 tank is made of carbon steel, coated with a corrosion-resistant acrylic polyurethane cover. The batch tank is configured in such a way that it allows the sludge and clarified effluent to be removed from the base of the tank. In conventional tanks, as the clarified effluent is removed from the base, the remaining sludge can clog/obstruct other devices in the tank (e.g. electrolytic cells) causing maintenance problems. Thus, in conventional tanks, solid waste would have to be removed from the top, which would imply another unit operation for the process. This increases the cost of operation by requiring the addition of paddles, skimmers and other mechanical devices.

[0021] The components of the system, including the batch tank 105, the electrolytic cell 110, a polymer mixing device or system 130, etc. are suitably mounted on a sliding platform 125. The sliding platform 125 may include a compact steel base frame. Other components of the system are described with reference to FIG. 4. Additional process equipment such as pumps, pipes, sensors or valves may be used throughout system 100. System 100 is configured to operate in automatic metering mode with minimal operator intervention. The system 100 may initialize sewage transfer and begin treatment based on the sewage treatment demand of the marine vessel.

[0022] Batch tank 105 is in fluid communication with an electrolytic cell 110. As used herein, the term "electrolytic cell" may encompass one, two, or multiple electrolytic cells (e.g., for use on larger marine vessels or storage units). treatment). The electrolytic cell 110 is deliberately positioned outside the batch tank 105. This reduces the components/parts contained in the batch tank 105. Furthermore, it also minimizes corrosion/wear and wear and makes maintenance of the electrolytic cell 110 more practical. (If the cell were placed in the batch tank, the tank would have to be completely drained before carrying out any maintenance work). A defoamer injection pump 442 is provided for injecting a small amount of diluted defoamer into an oxidized wastewater mixture leaving the electrolytic cell 110. The blower 120 can be configured to start upon energizing the electrolytic cell 110. A recirculation pump 140 is configured to recirculate a flow of oxidized wastewater through the in-line mixing coil/tubing 135.

[0023] System 100 includes an electrical control panel 150. Control panel 150 is simple and easy to operate. The control panel 150 uses a switching power supply and intelligent relay controllers as the basis for safe and effective operation of the system 100. All system components can be preconnected to the control panel 150.

[0024] FIGS. 2A and 2B illustrate isometric views of two exemplary configurations of the electrolytic cell 110A, 110B. The electrolytic cell can have a basically flat/book-shaped housing 110A or cylindrical 110B. Regardless of housing geometry (110A, 110B), the electrolytic cell 110 is configured to function as a primary component for eliminating bacteria/pathogens in wastewater by generating sodium hypochlorite and other oxidants from seawater. The electrolytic cell 110 is equipped with one or more pairs of opposing electrodes (not shown) which means, for example, a DC power supply, to apply electrical current between the electrodes (not shown). The electrical polarity of the electrodes in the electrolytic cell 110 may be reversed periodically (i.e., every 24 hours when the treatment system is operated continuously) to minimize maintenance. This action allows automatic cleaning of the electrodes to remove hard scale (calcium and magnesium). The treatment system 100 does not use electrolytic cells that have sacrificial electrodes typically subject to irregular wear, with the need for frequent replacement before they are completely worn out.

[0025] FIGS. 3A and 3B illustrate exemplary views of a polymer mixing system 130. A polymer mixing system 130 is provided for mixing pure polymers with a pre-measured volume of water, typically drinking water or utility water. Potable or non-potable water can be used, with the exception of sea water.

[0026] Now referring to FIG. 3A, the polymer mixing system 130 includes a polymer mixing chamber/column 310. The polymer mixing chamber/column 310 includes an automatic high shear polymer mixer 320 for mixing the pure polymer with non-potable water, with except seawater to produce a dilute polymer solution. Due to the highly viscous nature of most polymers, proper mixing is essential to allow the polymer to disperse into the process stream effectively without polymer clumps and "fish eyes." (Fisheye is a globular or partially hydrated polymer caused by inadequate dispersion during the mixing process). In one aspect, the mixer 320 consists of a square-bore high-shear head. The polymer mixing system 130 is provided with a motor 330 and a junction box for electrical connection to the motor 330. The motor 330 is functionally connected to the 320 mixer through a shaft - typically a transparent part of the tube. The 340 junction box provides the electrical connection for the polymer mixer motor.

[0027] Now referring to FIG. 3B, polymer mixing chamber/column 130 includes two switches, one for high liquid level 350A and one for low liquid level 350B. Switches 350A and 350B are adjusted at different heights to ensure that an optimal and precise amount of diluted polymer is added upstream of the in-line static mixing coil/tubing 135 into the recirculated oxidized wastewater, even when the system 100 is tilted or in an angular position, for example an inclination of 22.5 degrees.

[0028] Referring to FIGs. 1A and 1B, the diluted polymer is sent to the suppression chamber 115 by adding upstream of the in-line static mixing coil/tubing 135 by a diluted polymer injection pump 155.

[0029] An exemplary method of treating wastewater using system 100 is described with reference to FIG. 4. A new batch cycle begins with a filling cycle in which a predetermined volume of seawater 405 is sent to tank 105 by opening an automatic seawater inlet valve 407. seawater is transferred to the tank 105 by an internal seawater sprayer 410. The sprayer 410 may be configured along an upper portion of the tank 105. Seawater is a critical component of the treatment process since the Electrolytic oxidation/disinfection relies on it to generate the necessary amount of sodium hypochlorite to effectively remove organic elements and eliminate fecal coliform. The tank 105 is filled to a predefined tank level based on measurements received from a level sensor 409. It is understood that more than one level sensor can be used to detect the liquid level in the batch tank 105. Once The preset seawater level in batch tank 105 is reached, the seawater supply valve 407 is configured to automatically close/de-energize.

[0030] At the same time as the seawater stream is added to the batch tank 105, a stream of pure polymer is pumped from the pure polymer storage tank 430 to the polymer mixing chamber/column 310 by the injection pump. pure polymer 145. A pre-measured volume of potable or non-potable water, with the exception of seawater 435, can be piped into the polymer mixing chamber/column 310 by opening valve 437. The pure polymer and potable water or Non-potable materials, with the exception of sea water, are mixed well by a high shear mixer (as shown in Figure 3A) in the polymer mixing chamber/column 310 at a pre-adjusted flow rate to establish a usable polymer solution. diluted/mixed for flocculation or agglomeration of suspended solids in wastewater.

[0031] Once the preset seawater level is reached, the level sensor 409 may transmit a signal to a sewage transfer pump to transfer wastewater 415. A flow regulating ball valve (not illustrated), or another mechanism known in the art, may be placed in a wastewater transfer pump to ensure a desired or optimal flow rate to tank 105. Wastewater is topped up in batch tank 105 to a predefined level. Once the preset filling level is reached, the level sensor 409 can transmit a signal to terminate the wastewater transfer. Desired or optimal flow rates of wastewater and seawater may depend on the treatment capacity of the system 100.

[0032] A liquid level gauge/liquid level sight glass 420 may be connected to one side of the batch tank 105. The level gauge 420 is comprised of a transparent tube. The level gauge 420 provides a visual indication of an actual liquid level in the batch tank 105 as the liquid level in the tank changes. This provides a practical mechanism for an operator to monitor and determine actual liquid levels in batch tank 105.

[0033] The crusher/mill pump 425 is then energized. Valve 422 is opened and a stream of wastewater and a seawater mixture from the bottom of batch tank 105 is routed through grinder 425. Crusher 425 is configured to efficiently grind or macerate solids found in the water stream. residues down to a smaller particle size, aiming to provide numerous high surface areas to improve treatment and to help the residue mixture pass through the charged surfaces of the electrolytic cell 110 without the risk of clogging/covering the cell.

[0034] Bypass valve 427 is activated or energized to allow passage of the macerated wastewater mixture to electrolytic cell 110. Valve 427 may be a seal discharge solenoid valve. The electrolytic cell 110 is energized and the macerated wastewater mixture is effectively electrolyzed between opposing electrodes to form mixed oxidants. Oxidants mainly include sodium hypochlorite. Sodium hypochlorite can effectively oxidize the wastewater mixture. Sodium hypochlorite removes a significant amount of organic elements and eliminates fecal coliform. When in operation, the electrolytic cell 110 can generate fine gas bubbles to support particles at the water surface interface level. Recirculation of the wastewater mixture can continue for a predetermined period of time. For example, waste sludge may be recirculated through the electrolytic cell 110 for about 5 to 20 minutes. The oxidized/electrolyzed mixture is channeled from the electrolytic cell to a suppression chamber 115 that is in fluid communication with the batch tank 105. The blower 120 can be configured to start as soon as the electrolytic cell 110 is energized. A regenerative blower 120 is used to force ambient air into the vent line.

[0035] A defoamer storage tank 440 is provided for storing one or more diluted defoaming agents or defoamers. In one aspect, the defoamer is an organic defoamer. The defoamer can be derived from tall oil fatty acids (TOFA) and naturally occurring polyols to form a polyol diester. During the oxidation/electrolysis cycle, a defoamer injection pump 442 is activated to inject a small amount of diluted defoamer from the defoamer storage tank 440 into the oxidized wastewater mixture, leaving the electrolytic cell 110. The defoamer is used to control any excessive foam accumulation that occurs from any gas entrained within the suspended solids and to minimize foam formation in the oxidized stream exiting the electrolytic cell 110. Additionally, normally, the smaller bubbles coalesce into larger bubbles once which often roll across the cathode surface of the electrodes in the electrolytic cell 110. The inventors have discovered that the introduction of defoamer discourages this coalescing action.

[0036] During electrolysis, small bubbles of hydrogen, oxygen and other residual gases are produced as by-products. These gases are entrained in the oxidized flow. Upon exiting the electrolytic cell 110, the oxidized process/stream mixed with sodium hypochlorite and gases is routed to a suppression chamber 115. The suppression chamber 115 is mounted over the batch tank 105. As the process stream mixed with hypochlorite of sodium and gases enters the suppression chamber 115, the entrained gases produced during the electrolysis reaction are diluted with ambient air to less than 25% of the lower explosive level or LEL of hydrogen in air. The diluted gases are positively expelled from the suppression chamber 115 to a safe location via an expulsion line 445. This ensures that at least the largest process gas bubbles are safely discharged to the atmosphere. In this way, the remaining process stream is substantially degassed, with the exception of entrained micro/small gas bubbles.

[0037] The suppression chamber 115 further includes a distribution coalescing package 450. The coalescing package consists of a plurality of integral diffuser or flow diversion plates contained in a box/container. The oxidized flow containing the microbubbles is directed over the coalescing package 450. The flow is distributed through the plates 450 from where it falls/disperses on the surface of the water in the batch tank 105 as fine droplets rather than as a stream or continuous flow. The coalescing package 450 increases the current contact surface area to disperse and remove its flow energy.

[0038] The bottom of the suppression chamber 115, which contains the plates 450, opens into the batch tank 105. The suppression chamber 115 slows the flow of the stream and ensures that solid particles in the stream do not separate. The sensor 409 controls the filling volume and ensures that a predetermined air gap is maintained between the base of the coalescing pack 450 and the surface of the water in the batch tank 105. This predetermined air gap is preset, e.g. to about 2 to 8 inches, and preferably between 3 to 6 inches. This pre-adjusted gap ensures effective separation of solids in batch tank 105.

[0039] The pure/concentrated polymer can be stored in a pure polymer tank/container 430. The pure polymer storage tank 430 can also be mounted on a sliding platform (e.g., 125 shown in Figures 1A and 1B). Alternatively, the polymer may be removed from a container or storage container (not illustrated). The polymer is a flocculant/dehydrant that promotes the aggregation or agglomeration of suspended solids in wastewater. The polymer may be a cationic polymer. In one aspect, the cationic polymer is a cationic polyacrylamide. For example, the polymer is a copolymer of acrylamide and a quaternized cationic monomer (or an inverse polyacrylamide emulsion) of high molecular weight. The cationic polymer is a water-soluble flocculating agent, effective over a wide pH range (4.0 - 9.0).

[0040] As described previously, the polymer mixing chamber/column 310 includes two switches 350A and 350B for detecting a first level or a high level of the polymer solution and a second or a low level of the polymer solution. It is critical to monitor polymer levels in the 310 polymer mixing chamber/column in order to comply with IMO discharge standards. Two switches are essential to ensure that a correct amount of polymer mixture is added to batch tank 105. Through experiments, the inventors discovered that when the treatment system was in an inclined position, having just a single switch was not sufficient to produce a desired amount of polymer mixture in the batch solution. Therefore, the polymer mixing chamber/column 310 was configured with two switches as a safety feature to allow better control over the treatment process.

[0041] The recirculation pump 140 is energized and begins to recirculate the flow of oxidized wastewater through the in-line mixing coil/tubing 135 back to the suppression chamber 115. The diluted polymer injection pump 155 is also energized. This mixed polymer solution is then added and injected upstream of the in-line mixing coil/tubing 135 by the dilute polymer injection pump 155. Similar to the substantially degassed process flow, the polymer solution is dropped from the plates 450 into the mixing tank. batch 105. After the oxidized wastewater flow recirculation and diluted polymer injection cycle is complete, a short, quiet dwell time (e.g., about 5-15 minutes, and preferably about 10 minutes) is observed in the batch tank. The quiet residence time facilitates the concentration of solids in the oxidized stream as a layer of floating mass on the surface of the liquid volume of batch tank 105 and the separation of the clear effluent from the floating layer.

[0042] The plates 450 located in the suppression chamber 115 are configured so that the flow of oxidized wastewater containing diluted polymer is dispersed in an attenuating shower over the liquid surface interface of the tank volume 105. Subsequently, a very buoyant mass of suspended solids is formed on the surface of the water, where microbubbles are attached to the agglomerated masses. The agglomerated particles form a floating layer on the upper surface of the water in batch tank 150. This phenomenon is called "electroflotation". Thus, the solid particles from the original wastewater stream are now suspended by the gas bubbles on the surface of the batch tank water as a floating layer, while below this floating layer there is a substantially clear treated effluent that can be discharged overboard.

[0043] The polymer has two functions. Firstly, it attracts solid impurities suspended in wastewater and neutralizes their surface charge. Charge neutralization is fundamental to the electroflotation process. Secondly, it acts as a flocculant to initiate agglomeration of solid impurities contained in the oxidized wastewater stream. Microbubbles entrained from the electrolysis process are impacted at the water surface interface and promote the buoyancy of agglomerated particles found in the wastewater stream. The density of the agglomerated particles is such that they remain above the surface of a substantially clarified effluent.

[0044] After the residence time, valve 459 is activated by the solenoid to facilitate the passage of the clarified effluent. A recirculation pump 140 is energized to withdraw a clarified effluent through valve 457 and send it overboard or to any designated location. Before discharge overboard, a clarified effluent stream is neutralized by the addition of a sulfate-based chemical. A 485 neutralized treated stream is now substantially free of any residual chlorine. As the clarified effluent is removed, the layer of sticky agglomerated sludge runs down the walls of batch tank 105 and adheres to the sides of the tank. In one aspect, a portion of one or more side walls of the batch tank 105 slopes inward to facilitate the sliding of sludge to the bottom of the tank 105. The solids separator 455 is configured near the bottom of the batch tank 105. .The solids separator 455 consists of a piping accessory equipped with a "mushroom" shaped lid. The 455 solids separator is configured to ensure that there is no cross-contamination of the agglomerated sludge with the clarified effluent during pumping or discharge. In other configurations, the lid may be bell-shaped, convex, or umbrella-shaped. In another aspect, the solids separator 455 may be a "P-trap" piping accessory.

[0045] The solids separator 455 is further configured to avoid pumping the sludge with clarified supernatant/effluent. A "stop level" can be set on the top surface of the solids separator 455. Once the sensor 409 detects that the effluent level has reached the stop level, the recirculation pump 140 is de-energized. This action stops the drainage of the clarified effluent from batch tank 105 so that the agglomerate mass is not discharged along with the clarified effluent. Thus, the solids separator 455 acts as a collector for the agglomerated mass (due to the consistency/density of the agglomeration).

[0046] A small volume of clarified effluent may remain in the batch tank 105. The batch tank 105 further includes a wash sprayer 460. The wash sprayer 460 is within the batch tank 105, below a water sprayer. sea 410 and above a solid waste separator 455. Sprayer 460 performs an internal wash of all solid particles or debris along the inner walls of tank 105 at the beginning of each filling cycle. The wash sprayer 460 can be used to mix the solids remaining in the batch tank 105 with the clarified waste effluent to create a sludge. This "tank washing" step allows for adequate cleaning of the side walls of the tank 105 and facilitates adequate mixing of the sludge to allow removal from the tank 105 during the solids discharge cycle. The sludge includes about 0.8-2.5% solids by weight. Valve 422 is repositioned (or energized) to remove sludge through the bottom of solid waste separator tank 455. Grinder 425 is energized to recirculate the sludge through valves 427 and 462 and back to batch tank 105. This step is called the "Rinse Step" to prepare the remaining wet solids for discharge. After a short period of time, valve 462 is repositioned to allow discharge to the customer's drying/solids handling system or solids storage tank. The grinder pump 425 transfers the wet solids until a low shutdown level measurement is detected by a level sensor 409 in the batch tank 105. Upon reaching the low shutoff level, the grinder pump 425 is de-energized. Dump valve 462 is de-energized and returns to its "normal" position. This essentially completes a complete batch treatment cycle. Batch tank 105 is now empty again, and seawater can begin to fill it for the next treatment cycle. The automatic cycle of dosing operation may continue unless the system 100 is physically removed from the automatic operation mode or unless the system detects a fault or alarm.

[0047] Referring again to the neutralization process, in one aspect, a dechlorination unit 480 is provided. The dechlorination unit 480 includes a chemical injection pump or a metering pump 475. The substantially treated and clarified effluent leaving the tank batch 105 may be dechlorinated by adding optimal amounts of one or more dechlorinating chemicals such as sodium bisulfite, sodium sulfite, sodium thiosulfate or sulfur dioxide prior to discharge overboard. A start signal may be sent to the dechlorination unit 480 to inject a dechlorination chemical into the clarified effluent discharge stream. The dechlorinated effluent is pumped out until a "low level" switch point is detected by the sensor 409 in the batch tank 105. This de-energizes the recirculation pump 140 and the dechlorination signal is removed. The 459 effluent discharge valve is de-energized back to its "normal" position.

[0048] The chlorine content of the discharged effluent (< 0.5 mg/L) is configured to meet the requirements of IMO Resolution MEPC.227(64) for releasing effluents into the marine environment without further processing. Dechlorinated effluent is environmentally safe and substantially free of residual chlorine.

[0049] The dechlorinated effluent 485 can be drained by gravity through the piping. For example, system 100 may include a stainless steel centrifugal pump (not shown) to discharge the dechlorinated effluent to the outside. The discharged effluent consists of fecal coliforms below 100 cfu/100 ml, BOD5 below 17 mg/L, COD below 84 mg/L, TSS below 23 mg/L, pH between 6 and 8.5 and residual chlorine total less than 0.5 mg/L.

[0050] In one aspect, an online turbidity sensor/transmitter 470 monitors turbidity/total suspended solids levels in the treated clear effluent before it is dechlorinated and discharged overboard. The online turbidity sensor 470 can be positioned so that it can detect turbidity (in the Nephelometric Turbidity Unit (NTU)) in the discharge effluent before and/or after injection of the dechlorination chemical.

[0051] In one aspect, the discharge of 0.8 to 2.5% by weight of wet solids/sludge 465 can be collected in a sewage collection/equalization tank without a sliding platform. The sewage collection/equalization tank (not shown) may be provided by a customer/user of system 100.

[0052] In another aspect, the discharge of 0.8 to 2.5% by weight of wet solids/sludge 465 from the batch tank 105 may be subjected to additional treatment, such as drying treatment. FIG. 5 illustrates an exemplary block diagram for a system 500 for drying or compacting sludge generated during the wastewater treatment process described above with reference to FIG. 4. Drying system 500 is a centrifugal sludge drying system. The drying system 500 is configured to effectively dry sludge, which contains 0.8-2.5% wet solids, to a point where the dry sludge contains 10-13% solids by weight. Dried sludge can be classified as a "Class B" type of sanitary waste that can be disposed of in an approved Class B Municipal Landfill without the need for further treatment on land at a municipal treatment site. The operation of this drying system 500 can be automated. The drying system 500 may communicate with the treatment system 100 through a centrifuge system control panel (not shown).

[0053] The drying system 500 is operated in automatic mode. The drying system 500 is configured to transmit a signal, called a "centrifuge ready to receive" signal, when it is ready to begin drying operations on a sludge discharge received from the treatment system 100.

[0054] Referring now to FIG. 4 and FIG. 5, when the sludge from the treatment system 100 is ready to be sent to the drying system 500, the grinder pump 425 sends a signal of 0.8 to 2.5% by weight of wet solids/sludge flow 465 to the sludge collection tank 510 together with a signal, such as, a "sludge transfer" signal to the centrifuge unit 530 until the batch tank 105 is empty. During the sludge drying process, the sludge collection tank 510 is used as a compensation tank.

[0055] In the absence of the drying system 500, the customer would have to deal with the issue of storing a large mass and volume of sludge on board a vessel. For example, a large volume of sludge (containing 0.8 to 2.5% solids by weight) is generated after the first treatment cycle. The customer would need a warehouse with a huge capacity to store this volume of waste sludge depending on the duration of storage. In the process of drying the wet solids to 0.8-2.5% by weight, this is compacted to about 10 to 13% by weight concentrated solids. The centrate obtained from the drying process can be reused by recirculating it back to the batch tank, thus reducing the volume of seawater used. Therefore, the customer would only have to store a small volume of compacted mud on board the vessel. Valve 555 is an actuated ball valve that is opened to allow flow from hub 560 to be directed back to batch tank 105 in the treatment unit.

[0056] After the centrifuge 560 is sent back to the treatment system 100, the volume from the sludge collection tank 510 is transferred to the recirculation tank 520 via gravity flow through the on/off valve 516. This empties the sludge collection tank 510, being ready to receive a next batch of sludge/wet solids waste from the treatment system 100.

[0057] The drying system 500 may then send a signal, such as a "centrifuge ready to receive" signal to the treatment system 100 in preparation for the next batch of sludge transfer from the treatment system 100. drying 500 starts to operate when the recirculation tank 520 is full.

[0058] The recirculation pump 526 removes the sludge from the recirculation tank 520. The pump 526 passes the sludge flow through the centrifuge 530. In the centrifuge 530, centrifugal force, which is generated by high-speed rotations, is used to separate the solids entrained from the fluid. The 530 centrifuge includes an internal centrifugal bowl to receive fluid (not shown). In one aspect, as described in U.S. Patents 6,224,532, 6,461,286, 6,478,724, 6,932,757 and 7,044,904, the contents of which are incorporated by reference herein, the centrifuge 530 may include a master spindle configured to rotate about an axis, wherein the internal centrifugal bowl is connected to the master spindle to rotate with it; a drive shaft; and a scraping blade connected to the transmission shaft to rotate with it, wherein the scraping blade can selectively remove solids accumulated on an inner surface of the centrifugal bowl; and a clutch mechanism. When the sludge enters the rotating centrifuge, it forms a ring near the walls of the centrifuge bowl. Due to centrifugal force, the dehydrated denser solid material moves outward toward the walls of the centrifuge while at the same time liquid overflows from the centrifuge and drains by gravity into recirculation tank 520. The liquid is relatively devoid of solids. . The 10 to 13% solids by weight are retained on the centrifuge walls. This continues for a predefined time interval while the fluid is separated from the solids entrained in the flow. At the end of the predefined period of time, the centrifugation slows down to a stop and the dehydrated solids are scraped from the centrifuge using internal scrapers. As these solids are scraped/displaced from the vat, they can fall by gravity into the dry solids collection container 540. The dry solids collection container 540 can be placed below the centrifuge 530.

[0059] During this complete operation, level detectors 514 and 524 can monitor levels in associated tanks 510 and 520. Tanks 510 and 520 are equipped with atmospheric vents 512 and 522, respectively. Any centric water 550 remaining in the recirculation tank 520 can be discharged through valves 528 and 545 from the drying system 500.

[0060] In one aspect, the drying system can compact the sludge from 0.8-2.5% to 10-13% solids by weight, thereby reducing the mass and volume of sludge that needs to be eliminated. The customer then only needs to worry about discarding 10-13% solids by weight. The drying system 500 operates simultaneously with the batch treatment system 100.

[0061] In one aspect, wastewater treatment can be carried out on board a marine vessel. This onboard treatment is generally utilized in those locations where there is limited access to a municipal water treatment plant or equivalent facility. Examples of such locations are ships and off-shore drilling platforms.

[0062] One or more system configurations have a reduced physical space and, by reducing the number of components and the complexity of separating solids and liquids in wastewater (automatic valves, number of electrolytic cells, steel support structure for maintenance of routine, power supply, control systems), the system is easier to operate. This also reduces material and manufacturing costs.

[0063] Type Approval Certification Tests

[0064] The approval certification tests were carried out on the Applicant's treatment system under the supervision of the certifying body Bureau Veritas (BV). The treatment system was operated in accordance with the "Performance Testing Guidelines for Sewage Treatment Plants against Effluent Standards" adopted by the Marine Environment Protection Committee (MEPC) of the International Maritime Organization (IMO) in the MEPC resolution 2(VI) of December 3, 1976; and changes applied to MEPC 159(55) of October 13, 2006 and MEPC 227(64) of October 5, 2012.

[0065] Raw Sewage Characteristics for Type Testing: The quality of raw sewage during the entire type testing period meets the requirements stipulated in Section 5.2 of resolution MEPC.227(64). Table 1 lists the geometric mean and minimum and maximum values of TSS, BOD5, COD and Turbidity for raw (influent) sewage. Table 1 - Raw Sewage Characteristics during Treatment System Type Test Notes: TSS - Total Suspended Solids, BOD5 - 5-day Biochemical Oxygen Demand, COD - Chemical Oxygen Demand, FC - Fecal Coliform, TRC - Total Residual Chlorine, TN - Total Nitrogen and TP - Total Phosphorus. For geometric calculations, HR values analyzed as >20,000 CFU/100 mL are considered as 20,000 CFU/100 mL.

[0066] Characteristics of the dechlorination effluent in tests Type: This flow represents the released effluent leaving the treatment system. Table 2 lists the geometric mean, minimum, and maximum values of TSS, BOD5, COD and Turbidity of dechlorination effluents. Table 2 - Characteristics of the dechlorination effluent obtained by the Treatment System Notes: TSS - Total Suspended Solids, BOD5 - 5-day Biochemical Oxygen Demand, COD - Chemical Oxygen Demand, FC - Fecal Coliform, TRC - Total Residual Chlorine, TN - Total Nitrogen, TP - Total Phosphorus, NA - Not analyzed . For geometric calculations, TRC values recorded as 0.0 mg/L are considered as 0.001 mg/L, while BOD5 values recorded as <2.0 mg/L are considered as 2.0 mg/L.

[0067] Therefore, the present invention is well adapted to achieve the aforementioned purposes and advantages, as well as those inherent to it. The previous description is not intended to limit the invention, which can be used in different aspects or configurations without departing from its scope of application and whose scope is uniquely defined by the attached claims. Discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the basis of the prior art or were common general knowledge in the relevant field of the present invention prior to the priority date of each claim of the present application.

[0068] Furthermore, the specific illustrative configurations mentioned above may be changed or modified and all such variations are considered within the scope and purpose of the present invention. Although systems and methods are described in terms of "consisting of", "containing" or "including" various devices/components or steps, it is understood that systems and methods may also "consist essentially of" or "consist of" the various components and steps. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any range included within that range is specifically disclosed. In particular, each range of values (of the form "from approximately a to about b" or, equivalently, "from approximately a to b") disclosed herein should be understood as indicating all numbers and intervals falling within the broader range of values . Furthermore, the terms of the claims have their clear and common meaning, unless explicitly and clearly defined otherwise by the patent holder. Furthermore, the indefinite articles "one" or "ones", as used in the claims, are herein defined to mean one or more of the elements it presents. If there is any conflict in the uses of a word or term in this specification and one or more patents or other documents that may be incorporated herein by reference, definitions that are consistent with this specification shall be adopted.

Claims (18)

1. Batch method for wastewater treatment characterized by: filling a dosing tank (105) with seawater (405) until reaching a first predetermined level; transferring the waste water (415) to the metering tank (105) until a mixture of seawater and waste water in the metering tank (105) reaches a second predetermined level, wherein the waste water comprises suspended solid particles; subjecting a flow of mixture of seawater (405) and wastewater (415) to electrolysis within an electrolytic cell (110), wherein the electrolytic cell is mounted outside the dosing tank (105); channel the electrolyzed/oxidized current to a suppression degassing chamber (115), wherein the suppression degassing chamber (115) is mounted above the metering tank (105), wherein the degassing chamber (115) comprises a plurality of full-flow diffuser plates (450) and wherein the electrolyzed stream comprises entrained micro/fine gas bubbles generated during electrolysis, and wherein the entrained gas bubbles are configured to be dispersed (445) through the diffuser plates (450 ) flowing on a surface of seawater (405) and wastewater (415) in the metering tank (105) as fine droplets; injecting a diluted antifoam solution via a chemical injection pump (442) from an antifoam storage chamber (440) into the outlet of the electrolytic cell (110); injecting a diluted cationic polymer solution upstream of a mixing pipeline (135) in-line of the mixer (130), wherein the polymer solution is channeled into the suppression degassing chamber (115) substantially simultaneously with the electrolyzed current; allowing dispersion of the electrolyzed current mixed with the cationic polymer solution and the electrolyzed current through the diffuser plates (450) flowing like a fine shower over the seawater (405) and wastewater (415) in the dosing tank (105) , wherein the polymer solution facilitates the flocculation separation of solid particles suspended in the wastewater by electroflotation; creating a distinct floating layer of the flocculated solid particles fixed with the microbubbles is formed; and separating a substantially clarified effluent (485) from the flocculated layer; discharge the clarified effluent (485) from the dosing tank (105); the discharge of the clarified effluent (485) is terminated when a predetermined third level of clarified effluent in the tank (105) reaches a stop level (409), wherein the stop level is located above a solid trap (455); spraying the metering tank (105) with a clarified waste effluent (485) of mixed slurry remaining in the tank (105) to remove residual solid particles residing along an inner wall of the metering tank (105) which creates a slurry of wet solids / mud (465); capture of the flocculated layer in the dosing tank (105) using a solids trap (455) of the device so that it is prevented from being discharged with the clarified effluent (485), wherein the solids trap (455) comprises a piping accessory configured with a lid and wherein the lid is configured to prevent cross-contamination of the flocculated layer and the clarified effluent (485); pumping the flocculated layer of discharged wet solids/sludge (465) to a dewatering system (500), wherein the dewatering system (500) comprises a centrifuge unit (530) for dewatering the wet solids/sludge (465) into that the entrained solids are compacted to a desired level; and recirculating a concentrate (560) generated during the solids/sludge dewatering step to the batch tank for use during a subsequent treatment cycle. 2. Method, according to claim 1, characterized by the fact that it further comprises macerating (425) the suspended solid particles before the electrolysis step (110). 3. Method according to claim 1, further characterized by injecting a diluted antifoam solution by means of a chemical injection pump (442) from an antifoam storage chamber (440) into the outlet of the electrolytic cell (110) , in which the antifoam solution manages to reduce the accumulation of excess foam in the electrolyzed stream before being channeled to the suppression degassing chamber (115). 4. Method according to claim 1, characterized by the fact that it further comprises mixing, in an in situ polymer mixing system (130), a pure concentrated cationic polymer with a predetermined volume of service water (435 ) to produce the diluted polymer solution, wherein the polymer mixing system comprises a polymer mixing chamber/column (310). 5. Method according to claim 4, characterized by the fact that, simultaneously with transferring the seawater (405) to the dosing tank (105), pumping the pure concentrated cationic polymer (435) into the chamber / column of polymer mixture (310) for the mixing step. 6. The method of claim 4, further comprising providing the polymer mixing chamber/column (130) with a first upper level switch (350A) and a second lower level switch (350B) for detecting the levels of polymer solution in the polymer mixing chamber/column (130) and thus where switches are set at different heights to ensure that an optimal amount of the polymer solution is added to the metering tank (105). 7. Method, according to claim 1, characterized by the fact that it further comprises facilitating a sedimentation time cycle to allow separation of the substantially clarified effluent (485) from the flocculated layer (465). 8. Method, according to claim 1, characterized by the fact that it further comprises neutralizing the residual chlorine (480) in the clarified effluent (485) with one or more chemicals (475) before the discharge step. 9. Method, according to claim 8, characterized by the fact that it further comprises measuring the turbidity (470) of the clarified effluent (485) before and/or after the neutralization step. 10. Method, according to claim 1, characterized by the fact that it further comprises pumping the discharge of the flocculated layer of wet solids / sludge (465) from the dosing tank (105) to a sludge tank (510) until a closing level (409) is detected in the metering tank (105), wherein the closing level corresponds to a substantially empty metering tank. 11. Method, according to claim 10, characterized by the fact that it further comprises refilling the dosing tank (105) with seawater (405) to start a subsequent wastewater treatment cycle (415). 12. Method according to claim 1, characterized in that the concentrate (560) is added back to the dosing tank (105) before the addition of seawater (405) during the subsequent treatment cycle, and in that the concentrate (560) supplements seawater (405). 13. Batch system for treating wastewater, according to the method described in claim 1, characterized in that it comprises: a dosing tank (105) for receiving wastewater (415) and seawater (405), wherein the wastewater comprises suspended solid particles; an electrolytic cell (110) in operable communication with the water metering tank (105), wherein the electrolytic cell (110) is mounted outside the metering tank (105) and wherein the electrolytic cell (110) is configured to electrolyze a stream consisting of seawater (405) and wastewater mixture (415) is subjected to electrolysis within an electrolytic cell (110), wherein the electrolyzed stream comprises entrained micro/fine gas bubbles (445) generated during electrolysis; a suppression degassing chamber (115), wherein the suppression degassing chamber (115) is mounted above the metering tank (105) and is in fluid communication with the metering tank (105), wherein the degassing chamber (105) 115) comprises a plurality of integral flow diffuser plates (450) and wherein entrained gas bubbles (445) are configured to be dispersed through the flow diffuser plates onto a surface of seawater (405) and wastewater ( 415) in the dosing tank (105) as fine droplets; and an in situ polymer mixing system (130), wherein the polymer mixing system is configured to inject a diluted cationic polymer solution into the electrolyzed stream into an in-line mixing pipeline (135) that is connected to the degassing (115), in which the current electrolyzed with the cationic polymer solution is configured to be dispersed through the flow diffuser plates (450) as a fine shower over the seawater (405) and wastewater (415) in the tank doser (15), wherein the cationic polymer solution is configured to separate solid particles suspended in the wastewater (415) by electroflotation to form a distinct floating layer of flocculated solid particles above a clarified effluent (485); for mixing a pure polymer (430) with a stream of service water (435) to produce a polymer solution, wherein the polymer solution facilitates flocculation of the suspended solid particles in which the polymer mixing system (130) comprises a polymer mixing chamber (310), wherein the polymer mixing chamber has a first level switch (350A) and a second level switch (350B), wherein the switches are configured at different heights to ensure that a optimal and precise amount of the diluted cationic polymer is added upstream of an in-line mixing pipeline (135); wherein the metering tank (105) comprises a solids trap (455), the solids trap (455) comprising a piping accessory configured with a lid, wherein the lid is configured to prevent cross-contamination of the flocculated layer and the clarified effluent; wherein the metering tank (105) comprises one or more level sensors (409), wherein the one or more level sensors are configured to detect: a first predetermined fill level, wherein the first predetermined fill level corresponds to a predetermined seawater filling level (405) in the dosing tank (105); a second predetermined fill level, wherein the second predetermined fill level corresponds to a predetermined fill level of waste water (415) in the metering tank (105); and wherein the suppression chamber (115) comprises a coalescing package with integral flow diffuser plates (450) to disperse the polymer solution and electrolyzed stream as a fine shower over seawater (405) and wastewater (415 ) in the metering tank (105) to create a distinct floating layer of microbubble-fixed flocculated solid particles with substantially clarified effluent (485) below the flocculated layer. A predetermined stop level (409), wherein the stop level is located above the solids trap (455), and wherein the stop level (409) corresponds to a predetermined clarified effluent level achieved during draining the clarified effluent (485) from the dosing tank (105). 14. System, according to claim 13, characterized by the fact that the system (100) is mounted on skates (125). 15. System, according to claim 19, characterized by the fact that it further comprises an antifoam injector (442), wherein the antifoam injector (442) is located outside the dosing tank (105) and close to the electrolytic cell (110) . 16. System according to claim 13, characterized by the fact that it further comprises a dechlorination injector (480) for neutralizing the clarified effluent (485), wherein the dechlorination injector (480) is located in the vicinity of a port to discharge the clarified effluent (485). 17. System, according to claim 13, characterized by the fact that it further comprises a dehydration system (500) that receives the flocculated solid particles (465) in a form of wet sludge, wherein the dehydration system (500) comprises a centrifuge (530) to receive the flocculated solid particles (465) in a wet sludge form, separating the wet sludge into dehydrated solids (540) and centralize. 18. System, according to claim 17, characterized by the fact that the dehydration system (500) further comprises piping for the circulation (526) of a concentrate (520) generated from the centrifugation / dehydration (530) of the particles flocculated solids / wet slurry to the dosing tank (105).