SE2130300A1 - System and method for cleaning macerated scum - Google Patents

Abstract

Disclosed is a system for cleaning a macerated scum, the system comprising a pumpstation reservoir having an inlet for receiving a fluid, and a dividing wall, arranged below the inlet, configured to evenly divide the fluid on either side of the dividing wall, at least one pump comprising a pumpwheel arranged on a rotating shaft powered by a motor, and a stirrer paddle coupled with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex in the fluid in the pumpstation reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir; and a protective pipe that surrounds the at least one pump, wherein the protective pipe is configured to be detachable to access the at least one pump.

Description

SYSTEM AND METHOD FOR CLEANING MACERATED SCUM TECHNICAL FIELD The present disclosure relates generally to a treatment of floating scum in a collecting pumpstation of a sewage treatment plant for example; and more specifically, to systems for cleaning macerated scum. The present disclosure also relates to methods for cleaning macerated scum using the aforementioned systems. BACKG ROUND A challenge generally faced by sewage treatment plants is cleaning scum that forms as a layer on the surface of the sewage (or wastewater). A scum is typically a multi-phase medium containing solid, liquid, gas, as well as grease particles that gathers (or forms a layer) on the surface of a liquid, such as the sewage. Normally, long periods of sewage standing still and the lack of ventilation therein breeds hydrogen sulfide (H25) gas in the container holding the sewage, such as sewage pipes or sewage tanks (also referred to as pumpstation reservoirs). Notably, low density particles (namely, cellulose) of the sewage together with the H25 rise to the surface of the fluid forming a thick layer of scum on the sewage. Notably, the H25 is heavier than air, thus gets trapped inside the cellulose to form thick layer of scum that floats on the surface of the fluid. The thick layer of scum is corrosive on various components, such as pipes, pumps, and so on, of the sewage treatment plants. Therefore, it is important to break down (namely, macerate) such thick layer of scum and remove the macerated scum from the pumpstations of the sewage treatment plants.

Conventionally, to macerate the floating scum, an incoming fluid is delivered allowed to fall from a high drop height in to the sewage tanks, to macerate the thick layer of scum. Subsequently, a vortex is formed through a pumpwheel to suck the macerated scum and pump it onwards. However, conventional pump designs fail to generate a vortex strong enough to macerate the scum effectively. A solution to the low vortex problem with conventional pump design is provided by maintaining a continuous swirling motion of the sewage collected in the sewage tanks. Normally, in this regard, a stirrer is provided inside the sewage tank in addition to the pump. However, the presence of lumpy substances in the fluid continuously affect the operation of the pump and stirrer and also cause corrosion of the pump and stirrer. A solution to protect the pump (and stirrer) from corrosion and challenged operation thereof, a scum-removing device is installed in the sewage tanks along with a stirrer. However, having many components withing the sewage tank makes it difficult to install, replace, or maintain all the components ofthe sewage treatment plant, thus resulting in a decrease in overall efficiency thereof.

Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with conventional scum removing techniques. SUMMARY The present disclosure seeks to provide a system for cleaning a macerated scum. The present disclosure also seeks to provide a method for cleaning a macerated scum. The present disclosure seeks to provide a solution to the existing problem of thick layer of floating scum in a collecting pumpstation. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in prior art, and provides an efficient, reliable, user-friendly, and cost-efficient system.

In an aspect, an embodiment of the present disclosure provides a system for cleaning a macerated scum, the system comprising: - a pumpstation reservoir having: - an inlet for receiving a fluid, and - a dividing wall, arranged below the inlet, configured to evenly divide the fluid on either side of the dividing wall, - at least one pump comprising - a pumpwheel arranged on a rotating shaft powered by a motor, and - a stirrer paddle coupled with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex in the fluid in the pumpstation reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir; and - a protective pipe that surrounds the at least one pump, wherein the protective pipe is configured to be detachable to access the at least one pump.

In another aspect, an embodiment of the present disclosure provides a method for cleaning a macerated scum, the method comprising: - receiving a fluid into a pumpstation reservoir, wherein the pumpstation reservoir comprises an inlet for receiving the fluid and a dividing wall, arranged below the inlet, configured to evenly divide the fluid on either side of the dividing wall; - initiating, when the fluid reaches a high fluid level point inside the reservoir, at least one pump, wherein the at least one pump comprising: - a pumpwheel arranged on a rotating shaft powered by a motor, and - a stirrer paddle coupled with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex at the fluid in the reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir; and - stopping, when the fluid reaches a low fluid level point inside the reservoir, at least one pump.

Embodiments of the present disclosure substantially eliminate or at least partially address the aforementioned problems in the prior art, and enable efficient maceration of the floating scum and cleaning (namely, removal) of the macerated scum from the collecting pumpstation. In this regard, the system comprises a pumpstation reservoir having a dividing wall, arranged below the inlet to evenly divide the incoming fluid (sewage) on either side of the dividing wall to partially macerate the scum. Further maceration of the scum is achieved by a strong vortex generated by a pumpwheel of at least one pump, in particular the one that is energy efficient and cost-efficient. Moreover, the pumpwheel alongwith a stirrer paddle attached thereto generates a vortex in the fluid strong enough to completely macerate the scum. Furthermore, the at least one pump effectively pumps onwards the macerated scum with the fluid from the pumpstation reservoir. Additionally, the system comprises a protective pipe that surrounds the at least one pump to protect the pump from corrosion from the fluid and the scum.

Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments construed in conjunction with the appended claims that follow.

It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those skilled in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein: FIG. 1 is a cross-sectional view of a system for cleaning a macerated scum, in accordance with an embodiment of the present disclosure; FIG. 2 is a schematic illustration of a pump having a stirrer paddle coupled with the pumpwheel, in accordance with an embodiment of the present disclosure; and FIG. 3 is an illustration of steps of a method for cleaning a macerated scum, in accordance with an embodiment of the present disclosure.

In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing. DETAILED DESCRIPTION OF EMBODIMENTS The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.

In an aspect, an embodiment of the present disclosure provides a system for cleaning a macerated scum, the system comprising: - a pumpstation reservoir having: - an in|et for receiving a fluid, and - a dividing wall, arranged below the in|et, configured to evenly divide the fluid on either side of the dividing wall, - at least one pump comprising - a pumpwheel arranged on a rotating shaft powered by a motor, and - a stirrer paddle coupled with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex in the fluid in the pumpstation reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir; and - a protective pipe that surrounds the at least one pump, wherein the protective pipe is configured to be detachable to access the at least one pump.

In another aspect, an embodiment of the present disclosure provides a method for cleaning a macerated scum, the method comprising: - receiving a fluid into a pumpstation reservoir, wherein the pumpstation reservoir comprises an in|et for receiving the fluid and a dividing wall, arranged below the in|et, configured to evenly divide the fluid on either side of the dividing wall; - initiating, when the fluid reaches a high fluid level point inside the reservoir, at least one pump, wherein the at least one pump comprising: - a pumpwheel arranged on a rotating shaft powered by a motor, and - a stirrer paddle coupled with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex at the fluid in the reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir; and - stopping, when the fluid reaches a low fluid level point inside the reservoir, at least one pump.

The present disclosure provides the aforementioned system and the aforementioned method for cleaning the macerated scum from a collecting pumpstation. The system employs various components that are operatively coupled to form an advanced system for cleaning the macerated scum. In this regard, the system comprises a pumpstation reservoir having an inlet for receiving a fluid, and a dividing wall to evenly divide the fluid on either side of the dividing wall. Beneficially, the dividing wall at least partially macerate the scum while receiving it from the inlet. Moreover, the system comprises at least one pump comprising a pumpwheel arranged on a rotating shaft powered by a motor and a stirrer paddle coupled with the pumpwheel. Beneficially, the pumpwheel and the stirrer paddle are configured to generate a vortex in the fluid in the pumpstation reservoir to macerate the scum floating on the surface of the fluid and pump out the macerated scum with the fluid from the pumpstation reservoir. In said arrangement, the stirrer paddlewheel is arranged in a manner that the stirrer paddlewheel is simultaneously powered by the motor that powers the pumpwheel. Thus, the at least one pump is energy efficient and cost effective. The system also comprises a protective pipe that surrounds the at least one pump to protect the pump from corrosion. Furthermore, the protective pipe is configured to be detachable to access the at least one pump for maintenance, repair or replacement thereof. Moreover, the system comprises a high fluid level point and a low fluid level point, at which when the fluid in the reservoir reaches, the at least one pump initiates and stops the pumping of the fluid from the reservoir, thereby saving the overall energy required by the system.

The term "pumpstation reservoir" as used herein refers to a sealed underground storage space or a wet well (also referred to as a pumphouse) that is used to move sewage (or wastewater) from one site to another, such as from lower elevations to higher elevations in order to allow transport by gravity flow via gravity manholes to an end treatment plant. In this regard, the pumping reservoirs are normally designed to handle raw sewage that is fed from an underground pipeline leading from households or industrial complexes for example. It will be appreciated that the pumpstation reservoir is sized to be big enough to prevent rapid pump cycling and small enough to prevent a long detention time and associated gaseous release such as the hydrogen sulphide from building up inside the pumpstation reservoir due to long standing sewage. Additionally, the pumpstation reservoir may be fabricated using concrete or a suitable material (such as less corrosive material, for example stainless steel or polyethylene) to withstand the weight of the components and other chemical and mechanical stress in the system. Optionally, the pumpstation reservoir may have mechanical bar screens or grinders installed therein to minimize clogging problems in the system. The mechanical bar screens may be a coarse screening and a fine screening to maintain longitudinal and a non-turbulent linear flow.

The term "inlet" as used herein refers to a hollow tubular structure through which the fluid enters into the system. It will be appreciated that the inlet may have an appropriate size or a diameter to receive a continuous flow of fluid into the system. It will be appreciated that the incoming pipes carrying the fluid to the inlet of the pumpstation reservoir have varying sizes and cross- section throughout a length thereof based on the exit points (i.e. the households, industries, and so on) of the fluid as well as the size or a diameter of the inlet. In an example, the incoming pipe may be broad at the exit points ofthe fluid but narrow down closer to the in|et in order to fit the cross-sectional diameter of the inlet. Optionally, the incoming pipe has a diameter in a range from 80 mm to 1000 mm. The incoming pipe may typically range in diameter from 80, 90, 100, 150, 200, 400, 600 or 800 mm up to 90, 100, 150, 200, 400, 600, 800 or 1000 mm. The term "fluid" as used herein refers to sewage (namely, domestic Wastewater, municipal Wastewater, or industrial Wastewater) generated by various domestic or industrial activities by a community of people or industries. The fluid may typically include Wastewater discharged from residences, and from commercial, institutional and public facilities that exist in a locality. The sub-types of the fluid may be a greywater and a blackwater. The greywater is the fluid that comes from sinks, bathtubs, showers, dishwashers, clothes washers, and the like. The blackwater is the water used to flush toilets, combined with the human waste. Moreover, the fluid may also include food waste discharged with water released after dishwashing. Additionally, in regions where toilet paper is used rather than bidets, the used toilet paper is also added to the fluid. Yet additionally, the fluid may also include macro-pollutants and micro-pollutants from industrial Wastewater".

Optionally, the in|et is arranged at a pre-defined flow height from a base of the pumpstation reservoir. The term "pre-defined flow height" as used herein refers to a height of the in|et from which the fluid is allowed to fall into the pumpstation reservoir. Notably, the diameter of the in|et and a potential flowrate of the fluid falling from the pre-defined flow height will determine the rate of filling of the pumpstation reservoir and subsequent operations of the pumpstation.

The term "dividing Wall" as used herein refers to a wall subdividing the pumpstation reservoir, below the in|et, into two major portions. In such arrangement, as the fluid enters the pumpstation reservoir through the inlet, the fluid lands first on the diving wall. The dividing wall then roughly equally divides the fluid on both sides of the dividing wall to prevent accumulation of solid substances on only one side of the pumpstation reservoir. It will be appreciated that accumulation of solid substances on only one side of the pumpstation reservoir may lead to blocking the inlet over a period of time, thereby resulting in a potential backflow of the fluid from the sewage pipes into various discharging points. Moreover, the dividing wall enables that a disturbance entering the pumpstation reservoir does not affect the overall operation of the pumpstation. For example, the dividing wall prevents blocking all the pumps arranged inside the pumpstation reservoir. In this regard, the dividing wall enables initiating the pump on the side of the dividing wall that has received enough fluid to save power consumption by other pumps where the fluid has not reached a desired level.

However, it will be appreciated that a long-standing fluid (comprising the liquid phase and the solid phase), on either side of the dividing wall, in the pumpstation reservoir may lead to formation of scum in the pumpstation reservoir. Throughout the present disclosure, the term "scum" as used herein refers to a multi-phase medium containing the solid substances (such as the organic matters), liquid, gas, as well as grease particles that forms a thick layer on the surface of a long-standing (negligibly or low-ventilated) liquid in a pumpstation. Moreover, the solid substances may be digested by bacteria to form a sludge and produce a gas by-product. The gas captures light-weight digested particles and rises to the surface of the long-standing liquid to form the scum. Additionally, besides digestion, the scum may be generated from chemical precipitation, sedimentation, and other such processes occurring in the long-standing liquid.

It will be appreciated that the scum cuts out the air-passage between top sections of the pumpstation reservoir and the liquid therein. Moreover, the scum is very corrosive on all items it is in contact with (such as pumps). Therefore, it is important to break (namely, macerate) the scum to enable air passage and avoiding a potential hazardous explosion inside the pumpstation or a potential back-flow of the sewage (or wastewater) out of the pumpstation reservoir into pipes leading from households.

Throughout the present disclosure the term "macerated scum" as used herein refers to smaller pieces of solid substances that are broken down to reduce the sewage waste to a slurry that is subsequently moved out of the pumpstation reservoir by operations such as pumping. Conventionally, the process of maceration, in sewage treatment plants for example, may use a machine such as a chopper pump that is equipped with a cutting arrangement (such as knives). In this regard, the chopper pump is installed in the sewage lift station or at the wastewater treatment plant. Notably, the cutting arrangement of the chopper pump facilitates chopping or maceration of solid substances that are present in the sewage for example. Thereby preventing clogging ofthe pumps and associated pipe arrangement. It will be appreciated that after maceration of the scum, the macerated scum comprises small insoluble (and often undigested) particles and one or more gases released as a result of various chemical or biological processes occurring during the maceration of the scum.

Optionally, the macerated scum includes at least one of: cellulose and hydrogen sulfide. The term "ce//u/ose" as used herein refers to an organic compound or a long linear polysaccharide polymer consisting of ß-1,4-linked D-glucose units ((C5H8O4)n). The cellulose may be found in natural resources such as plants, fibers, woods, stalks, stems, shells, straw, grasses, algae, bacteria, and so forth. Moreover, the macerated scum includes a significant proportion of the cellulose therein. In an example, the macerated scum may include the cellulose due to the presence of toilet paper in the sewage. In another example, the macerated scum may include the cellulose due to the application of natural and modified types of cellulosic materials as adsorbents, flocculants, and cellulose membranes in order to remove organic and inorganic pollutants from sewage. The said organic and inorganic pollutants may be heavy metals. Moreover, the macerated scum also includes a hydrogen sulfide (H25). The hydrogen sulfide is a colorless chalcogen hydride gas with a characteristic foul odor of rotten eggs. Moreover, the hydrogen sulfide is poisonous, corrosive, and flammable in nature. Typically, the hydrogen sulfide may be produced from microbial breakdown (anaerobic digestion by sulfate- reducing microorganisms) of organic matter in the absence of oxygen, such as in swamps and sewers. Additionally, the amount of the hydrogen sulfide embedded in the macerated scum may depend on the duration of sewage that has been standing still in the system. It will be appreciated that the hydrogen sulfide gas in the macerated scum will rise to the surface of the liquid in the sewage. Moreover, the cellulose particles having the lowest density may also rise to the surface of the liquid in the together with the hydrogen sulfide gas. In other words, the hydrogen sulfide gas will rise and take the cellulose particles to the surface of the liquid. Moreover, the hydrogen sulfide gas is heavier as compared to the other gases (air) inside the pumpstation reservoir, and thus stays at the surface of the sewage embedded in the cellulose.

Optionally, the particle size of the macerated scum is less than 5mm. Optionally the particle size of the macerated scum is in a range of 0.001 to 5mm. For example, the particle size of the macerated scum may be in a range of 0.001, 0.003, 0.006, 0.009, 0.012, 0.015, 0.03, 0.06, 0.12, 0.24, 0.48, 0.6, 0.9, 1.2, 1.5, 3.00 or 4.50 mm up to 0.003, 0.006, 0.009, 0.012, 0.015, 0.03, 0.06, 0.12, 0.24, 0.48, 0.6, 0.9, 1.2, 1.5, 3.00, 4.50 or 5 mm. Moreover, the cellulose and the hydrogen sulfide may combine together to form a thick and dense layer on the surface of the liquid of the sewage. The said layer is corrosive in nature and results in corrosion of components (such as the pumps) in the system.

The term "at /east one pump" as used herein refers to one or more pumping devices, powered by electrical energy, that are configured to move the fluids (or slurries), by mechanical action, typically resulting from conversion of the electrical energy into hydraulic energy, from one site to another, when in operation. Moreover, the at least one pump may operate by mechanisms such as reciprocating mechanism or rotary mechanism. Furthermore, the at least one pump may operate via energy sources such as manual operation, electricity, engines, or wind power. Moreover, the at least one pump can be powered by direct current (DC) sources, such as batteries or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters or electrical generators. Optionally, the at least one pump may come in various sizes based on at least one of: the size of the pumpstation of the fluid that needs to be pumped. Beneficially, the at least one pump may have wide range of applications, besides moving the fluid between sites, such as providing aeration in the system, efficiently mixing the constituents of the fluid to form a smooth slurry, and so on. Typically, the at least one pump is efficient, lightweight, robust, are mechanically simple and cheap to manufacture. Optionally, the pump may be a direct lift pump, a displacement pump, a gravity pump, a centrifugal pump, and so forth. In an embodiment, the pump is a displacement pump. Optionally, the displacement pump is a positive displacement pump. Typically, the positive displacement pump is configured to move a fluid by repeatedly enclosing a fixed volume and moving it onwards mechanically though the system. Beneficially, the positive displacement pump can move higher viscosity fluid onwards and can operate at a high pressure and relatively low flows more efficiently.

The at least one pump comprises a pumpwheel arranged on a rotating shaft powered by a motor, and a stirrer paddle coupled with the pumpwheel. The term "pumpwheel" as used herein refers to a mechanical component present at the bottom of the at least one pump. The pumpwheel is rotationally coupled with the rotating shaft and has a stirrer paddle attatched thereto. The term "stirrer paddle" as used herein refers to a mechanical component such as a stirrer or an agitator, for generating additional vortex by the at least one pump for the purpose of macerating the f|uids. Herein, the stirrer paddle is mounted at an end of the pumpwheel. It will be appreciated that as the at least one pump runs, the vortex is strong enough to pull the macerated scum in to the at least one pump and pump it onwards. In this regard, the pumpwheel and the stirrer paddle are configured to generate a combined, stronger vortex in the fluid in the pumpstation reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir. Furthermore, the stirrer paddle is operatively coupled with the pumpwheel either directly or via a planetary gear-reducer.

The term "vortex" (plural: vortices) as used herein refers to a region in a fluid in which the flow revolves around an axis line, which may be straight or curved. Vortices are a major component of turbulent flow. Moreover, the distribution of velocity, vorticity (the curl of the flow velocity), as well as the concept of circulation may be used to characterize vortices. Typically, in most vortices, the fluid flow velocity is greatest next to its axis and decreases in inverse proportion to the distance from the axis. Furthermore, in the absence of external forces, viscous friction within the fluid tends to organise the flow into a collection of irrotational vortices, possibly superimposed to larger-scale flows, including larger-scale vortices. Additionally, once formed, the vortices may move, stretch, twist, and interact in complex ways. In this regard, the moving vortex may have angular and linear momentum, energy, and mass as the moving vortex may have open particle paths. Optionally, two or more vortices may come close together and merge to form a stronger vortex.

Optionally, the scum is at least partly macerated when the fluid is received into the pumpstation reservoir from a pre-defined flow height of the inlet, and remaining scum floating on the surface is macerated by the vortex generated by the pumpwheel and the stirrer paddle. Notably, the fluid that falls from the pre-defined flow height partially breaks the layer of cellulose and H25 that is formed on the surface of the fluid accumulated in the pumpstation reservoir, and optionally, the scum that is received from the inflowing fluid from the inlet. In this regard, the breaking of the layer of cellulose and H25 partly macerates the scum into the pumpstation reservoir. Moreover, the remaining scum floating on the surface is macerated by the strong enough vortex generated by the pumpwheel and the stirrer paddle.

Optionally, the pumpstation reservoir has a high fluid level point and a low fluid level point at which the at least one pump starts and stops, respectively. The term "high fluid level point" as used herein refers to a maximum height achieved by the accumulated fluid inside the pumpstation reservoir at which the at least one pump is initiated to macerate the scum and pump onwards the macerated scum. Notably, the high fluid level point functions as a starting point at which the at least one pump initiates to generate vortex to macerate the scum and pump onwards the macerated scum from the pumpstation reservoir. Moreover, the high fluid level point may also function as a safety factor built into the pumpstation reservoirs. In this regard, in an event when the actual inflow of the fluid far exceeds the max predicted inflow, or a pump fails, an alarm may be triggered to indicate, to the station operators, that the high fluid level point has been reached and the inflow of the fluid may be reduced or stopped. The term "/ow fluid level point" as used herein refers to a minimum height achieved by the accumulated fluid inside the pumpstation reservoir at which the at least one pump stops cleaning the macerated scum from the pumpstation reservoir. Notably, the low fluid level point enables a minimum submergence of the at least one pump in the fluid to prevent the at least one pump from corrosion by the scum, as well as prevents air from entering inside the at least one pump. Beneficially, the low fluid level point is high enough to have liquid surrounding the at least one pump and floating scum on surface thereof, thereby preventing the at least one pump from corrosion by the floating scum. Therefore, higher the low level fluid point the better it is for the corrosion protection of the pumps. Moreover, it will be appreciated that the higher low fluid level point results in a lower drop height of the incoming fluid, however, the novel design of the disclosed system, having a dividing wall as well as strong vortex generated by the pumpwheel and the stirrer paddle, overcomes the lower drop height of the incoming fluid by effectively macerateing the floating scum. Additionally, beneficially, the high fluid level point and the low fluid level point optimizes the overall energy consumption by the system and allows smooth functioning of the at least one pump.

Optionally, the pumpstation reservoir comprises a level sensor that is configured to detect the high fluid level point and the low fluid level point. The term "/eve/ sensor" as used herein refers to a sensor that detects the levels of fluids inside the pumpstation reservoir. It will be appreciated that the level sensor enables the accurate measurement and control of the level to ensure that the fluid may not get too high or may get too low as the pumps are designed to allow the fluids only and if too much air is injected then damage to the pumps may occur. The level sensor takes measurement that may be either continuous or point values. Moreover, the continuous level sensors measure level within a specified range and determine the exact amount of the fluid in a certain place, while point-level sensors may indicate whether the fluid is above or below the sensing point. Furthermore, the selection of the level sensor may depend on physical variables such as the phase (liquid, solid or slurry) of the fluid, a dielectric constant of the fluid, a density (specific gravity) of the fluid, a temperature inside the pumpstation reservoir, a pressure or vacuum pumpstation reservoir, a chemical composition pumpstation reservoir, mechanical forces inside the pumpstation reservoir, an acoustical or electrical noise inside the pumpstation reservoir, the design of the pumpstation reservoir, and so forth. Additionally, the level sensors may also be selected based on the application constraints such as cost, accuracy, appearance, response rate, ease of calibration or programming, and monitoring or control of continuous or discrete (point) fluid levels. Furthermore, the level sensors may be designed using a variety of sensing principles. In this regard, the level sensors may work in conjunction with the system to save the energy consumption by the at least one pump. Optionally, the level sensor may be an optical level sensor, an ultrasonic level sensor, a float level sensor, a capacitance level sensor, a conductivity or a resistance level sensor, and the like. In an example, the level sensor is the optical level sensor that may be compact, having no moving parts, and works under high pressure and temperature to detect the high level fluid points and the low level fluid points in the pumpstation reservoir of the system. In another example, the level sensor is the conductivity or a resistance level sensor that may be suitable in highly corrosive liquids.

Optionally, a height of the dividing wall from the base of the pumpstation reservoir is lower than the pre-defined flow height of the inlet, and wherein the low fluid level point in the pumpstation reservoir, that partly submerges the at least one pump, is up to 50% of the height of dividing wall. As mentioned before, the dividing wall is provided below the inlet, therefore, the height of the dividing wall is lower than the pre-defined flow height of the inlet. Moreover, the low fluid level point is at most 50% of the height of the dividing wall. In an example, the low fluid level point may be from 20% to 50% of the height of the dividing wall. Notably, the low fluid level point partially submerges the at least one pump. Optionally, the high fluid level point in the pumpstation reservoir is up to 50% of the height of the at least one pump. It will be appreciated that the high fluid level point is at most 50% of the height of the at least one pump. In an example, the high fluid level point may be from 20% to 50% of the height of the dividing wall.

The term "protective pipe" as used herein refers to an elongated ho||ow tubular structure that surrounds the at least one pump. The protective pipe has a cross-section, a shape and a size to accommodate the at least one pump therein. The protective pipe has a cross-section slightly larger than the cross- section of the at least one pump to be able to surround the at least one pump. It will be appreciated that the term "slightly larger cross-section" as used herein refers to a diameter of the protective pipe that is larger than the cross- sectional diameter of the at least one pump in a range of 5-10 cm. A slightly larger cross-section of the protective pipe also allows for smooth conveyance of the fluids from the pumpstation reservoir into the pump for pumping onwards the macerated scum. Optionally, the cross-section of the protective pipe may vary from a circular, a tubular, or a polygonal cross-section, depending on the cross-section of the at least one pump. The ho||ow and slightly larger cross-section of the protective pipe protects the pumps from the corrosive effects of the floating scum while still enabling the pump to be at least partly submerged in the slurry of macerated scum (achieved by the vortex generated by the pumpwheel and the stirrer paddle) However, the protective pipe prevents the larger chunks of macerated scum present in the fluid from entering in the space between the at least one pump and the protective pipe. The outer surface of the protective pipe is continuously in direct contact with the floating scum and the inner surface is in contact with the fluid (or slurry) only. In this regard, the protective pipe prevents the direct contact of the cellulose present in the floating macerated scum with the at least one pump. It will be appreciated that while the at least one pump is waiting for a high fluid level point to be reached by the accumulated fluid to start the next pump cycle, the at least one pump is protected from the macerated scum or floating scum due to the protective pipe. The protective pipe surrounds the at least one pump such that the protective pipe and the at least one pump does not touch the bottom of the pumpstation reservoir and have gap therebetween and only allows the fluid to enter from the hollow portion. It will be appreciated that the protective pipe is not coupled (or bonded) to the at least one pump. The protective pipe is detachable from the at least one pump to allow a potential repair, replacement or maintenance of the at least one pump.

Optionally, the protective pipe is fabricated from a plastics material. It will be appreciated that the protective pipe is fabricated from a non-corrosive material, such as plastics (or alternatively, high-grade stainless steel) to protect the at least one pump from corrosive effects of the surrounding fluid. It will be appreciated that the fabrication of the protective pipe from the plastics reduces the weight of the protective pipe in comparison to traditional steel or iron pipes. The plastic protective pipe may also provide resistance against corrosion and chemicals to the pump as well as to itself. Beneficially, the plastic protective pipes may be installed without heavy equipment in the pumpstation reservoir. Furthermore, the transportation and cutting of the plastic protective pipes into various sizes is much easier. Additionally, the fabrication of the individual parts of the protective pipe from the plastic material enables the protective pipe to have much longer lengths, thereby reducing the required number of fittings. Furthermore, the reduced number of fittings leads to the reduction of time required for connecting the individual parts enormously. Beneficially, the aforementioned feature may also save the cost of the system.

Optionally, the plastic material may be a Polyvinyl chloride (PVC), an Acrylonitrile Butadiene Styrene (ABS) plastic, and the like. Advantageously, the PVC pipe are easy to install, lightweight, strong, durable and easily recyclable, making them cost-efficient and sustainable. Moreover, the smooth surface of PVC pipes encourages faster water flow due to lower amounts of friction than pipes made from other materials such as cast iron or concrete. Furthermore, the PVC pipes may be manufactured to varying lengths, wall thicknesses and diameters, according to international sizing standards. Additionally, the ABS plastic pipes may contain some pigments to make the protective pipe and fittings resistant to degradation. In this regard, the ABS pipe and fittings may withstand the normal temperatures encountered in the pu mpstation reservoi r.

Optionally, the protective pipe when coupled with the pumpwheel and the stirrer paddle results in a strong vortex. Besides protecting the at least one pump from the corrosive effects of the macerated scum and potential operational hindrance by larger chunks of macerated scum, the protective pipe contributes to a stronger vortex. In this regard, the pumpwheel, the stirrer paddle and the protective pipe when operatively couple to generate a stronger vortex around the at least one pump. Optionally, the protective pipe is configured to generate the vortex in the fluid in the pumpstation reservoir to macerate the scum floating on a surface of the fluid. The protective pipe surrounding each pump, together with the pumpwheel and the stirrer paddle, generates vortex strong enough to macerate the scum and convert the macerated scum into a slurry. Moreover, when the at least one pump runs, the strong vortex pulls the slurry (comprising cellulose and dissolved hydrogen sulfide) in to the at least one pump and pumps it onwards.

Optionally, the pumped out fluid flows into at least one outgoing pipe, wherein a diameter of the at least one outgoing pipe ranges from 32 mm to 65mm. The term "outgoing pipe" as used herein refers to the pipe which is usually connected to the outlet of the at least one pump and is configured to transfer the macerated scum slurry from the pumpstation reservoir to the a different site, such as to another pumpstation reservoir or to a water treatment plant. The outgoing pipe may typically range in size from 32, 35, 38, 41, 44, 47, 50, 53, 56, 59 or 62 mm up to 35, 38, 41, 44, 47, 50, 53, 56, 59, 62 or 65 mm.

Typically, the at least one pump macerates the floating scum to the particle size <5mm and pumps onwards to the outgoing pipe. Notably, the outgoing pipe is full of macerated scum and the fluid, without air, and connects to other pumpstation reservoir and/or the water treatment plant. The macerated scum and the fluid in the outgoing pipe can only move forward in the outgoing pipe when at least of the pump connected to it is in operation.

Optionally, the at least one outgoing pipe is selected from a gravity pipe or a pressure pipe. The outgoing pipe have a greater diameter which allows fluid to run downwards to the next pumpstation reservoir or the water treatment plant. Optionally, the at least one outgoing pipe is the gravity pipe. In this regard, the gravity pipe has a 1% slope which moves the fluid due to the force of gravity. Moreover, the gravity pipe is rarely completely full of macerated scum and the fluid as fluid keeps on moving due to gravity and fluid levels have a certain height and have air above it. Moreover, the air in the gravity pipe reduces the amount of H25 in the fluid. Optionally, the at least one outgoing pipe is the pressure pipe. Typically, the pressure pipe usually has a diameter slightly lower than the gravity pipe and transfers the macerated scum and the fluid from the pumpstation reservoir to other the pumpstation reservoir or to the water treatment plant. In an embodiment, the pressure pipe may be implemented as a pressure sewer transport pipe to which no additional pumpstations could be connected. In another embodiment, the pressure pipe may be implemented as a pressure sewer system pipe to which additional pumpstations could be connected.

The present disclosure also relates to the method as described above. Various embodiments and variants disclosed above apply mutatis mutandis to the method.

Optionally, the protective pipe is configured to generate the vortex in the fluid in the pumpstation reservoir to macerate the scum floating on the surface of the fluid.

Optionally, the pumpstation reservoir comprises a level sensor that is configured to detect the high fluid level point and the low fluid level point.

Optionally, the scum is at least partly macerated when the fluid is received into the pumpstation reservoir from a pre-defined flow height of the inlet, and remaining scum floating on the surface is macerated by the vortex generated by the pumpwheel and the stirrer paddle.

Optionally, a height of the dividing wall from the base of the pumpstation reservoir is lower than the pre-defined flow height of the inlet, and wherein the low fluid level point in the pumpstation reservoir, that partly submerges the at least one pump, is up to 50% of the height of dividing wall.

Optionally, the high fluid level point in the pumpstation reservoir is up to 50% of the height of the at least one pump. DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG. 1, there is illustrated a cross-sectional view of a system for cleaning a macerated scum 100, in accordance with an embodiment of the present disclosure. The system 100 comprises a pumpstation reservoir 102 having an inlet 104 for receiving a fluid, and a dividing wall 106, arranged below the inlet 104, configured to evenly divide the fluid on either side of the dividing wall 106, at least one pump, such as the pump 108, comprising a pumpwheel (not shown) arranged on rotating shaft powered by a motor, and a stirrer paddle (not shown) coupled with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex in the fluid in the pumpstation reservoir 102 to macerate the scum floating on a surface of the fluid, and wherein the pump 108 is configured to pump out the macerated scum with the fluid from the pumpstation reservoir 102 and a protective pipe 110 that surrounds the pump 108, wherein the protective pipe 110 is configured to be detachable to access the pump 108. The protective pipe 110 is configured to generate the vortex in the fluid in the pumpstation reservoir 102 to macerate the scum floating on a surface of the fluid The pumpstation reservoir 102 has a high fluid level point A and a low fluid level point B from a base of the pumpstation reservoir 102 at which the pump 108 starts and stops, respectively.

Referring to FIG. 2, there is a schematic illustration of a pump 200 having a stirrer paddle 202 coup|ed with the pumpwheel 204, in accordance with an embodiment of the present disc|osure. The rotation of the pumpwheel 204 and the stirrer paddle 202 provides a stronger vortex to macerate the scum and transfer the macerated scum from the pumpstation reservoir (such as the pumpstation reservoir 102 of FIG. 1) onwards to an outgoing pipe 206. When the pump 202 is turned on, the motor inside the pump 202 starts and rotates a rotating shaft, the rotation of the rotating shaft creates a pressure that pushes fluid into the rotating shaft and further transfers the macerated scum into the outgoing pipe 206.

Referring to FIG. 3, there is shown a flowchart 300 i||ustrating steps of a method for c|eaning a macerated scum, in accordance with an embodiment of the present disc|osure. At step 302, a fluid is received into a pumpstation reservoir. The pumpstation reservoir comprises an in|et to receive the fluid and a dividing wall, arranged below the in|et, configured to evenly divide the fluid on either side of the dividing wall. At step 304, when the fluid reaches a high fluid level point inside the reservoir the at least one pump is initiated. The at least one pump comprises a pumpwheel arranged on a rotating shaft powered by a motor, and a stirrer paddle coup|ed with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex at the fluid in the reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir. At step 306, when the fluid reaches a low fluid level point inside the reservoir at least one pump is stopped.

The steps 302, 304 and 306 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.

Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

Claims (17)

Claims

1. A system for cleaning a macerated scum, the system comprising: - a pumpstation reservoir having: - an inlet for receiving a fluid, and - a dividing wall, arranged below the inlet, configured to evenly divide the fluid on either side of the dividing wall, - at least one pump comprising - a pumpwheel arranged on a rotating shaft powered by a motor, and - a stirrer paddle coupled with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex in the fluid in the pumpstation reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir; and - a protective pipe that surrounds the at least one pump, wherein the protective pipe is configured to be detachable to access the at least one pump.

2. A system according to claim 1, wherein the pumpstation reservoir has a high fluid level point and a low fluid level point at which the at least one pump starts and stops, respectively.

3. A system according to claim 2, wherein the pumpstation reservoir comprises a level sensor that is configured to detect the high fluid level point and the low fluid level point.

4. A system according to any of the preceding claims, wherein the protective pipe is fabricated from a plastics material.

5. A system according to any of the preceding claims, wherein the protective pipe when coupled with the pumpwheel and the stirrer paddle results in a strong vortex.

6. A system according to any of the preceding claims, wherein the macerated scum includes at least one of: cellulose and hydrogen sulfide.

7. A system according to any of the preceding claims, wherein the particle size of the macerated scum is less than 5mm.

8. A system according to any of the preceding claims, wherein the pumped out fluid flows into at least one outgoing pipe, wherein a diameter of the at least one outgoing pipe ranges from 32 mm to 65mm.

9. A system according to any of the preceding claims, wherein the at least one outgoing pipe is selected from a gravity pipe or a pressure pipe.

10. A system according to any of the preceding claims, wherein the inlet is arranged at a pre-defined flow height from a base of the pumpstation reservoir.

11. A system according to any of the preceding claims, wherein the protective pipe is configured to generate the vortex in the fluid in the pumpstation reservoir to macerate the scum floating on a surface of the fluid.

12. A method for cleaning a macerated scum, the method comprising: - receiving a fluid into a pumpstation reservoir, wherein the pumpstation reservoir comprises an inlet for receiving the fluid and a dividing wall, arranged below the inlet, configured to evenly divide the fluid on either side of the dividing wall; - initiating, when the fluid reaches a high fluid level point inside the reservoir, at least one pump, wherein the at least one pump comprising: - a pumpwheel arranged on a rotating shaft powered by a motor, and - a stirrer paddle coupled with the pumpwheel, wherein the pumpwheel and the stirrer paddle are configured to generate a vortex at the fluid in the reservoir to macerate the scum floating on a surface of the fluid, and wherein the at least one pump is configured to pump out the macerated scum with the fluid from the pumpstation reservoir; and - stopping, when the fluid reaches a low fluid level point inside the reservoir, at least one pump.

13. A method according to claim 12, wherein the protective pipe is configured to generate the vortex in the fluid in the pumpstation reservoir to macerate the scum floating on the surface of the fluid.

14. A method according to claim 12, wherein the pumpstation reservoir comprises a level sensor that is configured to detect the high fluid level point and the low fluid level point.

15. A method according to claim 12, wherein the scum is at least partly macerated when the fluid is received into the pumpstation reservoir from a pre-defined flow height of the inlet, and remaining scum floating on the surface is macerated by the vortex generated by the pumpwheel and the stirrer paddle.

16. A method according to claim 12 to 15, wherein a height of the dividing wall from the base of the pumpstation reservoir is lower than the pre-defined flow height of the inlet, and wherein the low fluid level point in the pumpstation reservoir, that partly submerges the at least one pump, is up to 50% of the height of dividing wall.

17. A method according to claim 12 to 16, wherein the high fluid level point in the pumpstation reservoir is up to 50% of the height of the at least one pump.