Description:TECHNICAL FIELD

[0001] The present disclosure relates to system for waste water treatment. Particularly, but not exclusively, the present disclosure is directed towards a low-cost, integrated faecal sludge treatment system that breaks down sludge into water and dry manure.
BACKGROUND
[0002] Fecal sludge is the partially degradable solid or semi-solid material that settles in the tanks of on-site sanitation systems (such as pit latrines, septic tanks, or other dry toilet types). Given global urbanization rates and heavy dependence on on-site sanitation systems in many regions of the world, particularly low or middle- income countries, fecal sludge management (FSM) is emerging as a crucial aspect of public health, environmental sustainability, and urbanization efforts. Nowadays, treating faecal sludge at a fair price is challenging. Sewage sludge is usually poured into rivers, the ocean, and other waterways, contaminating groundwater and harming aquatic life. Outside of large towns, faeces are commonly dumped directly into large pits, where they act as a haven for a variety of organisms that can cause cholera, typhoid, hepatitis, ringworm, and other illnesses. Thus, a more effective, all-inclusive, and cost-effective microbiological-oriented low-cost faecal sludge treatment solution is needed, one that breaks down the sludge into water and eliminates heavy metals and other contaminants. In addition to industrial uses, this water could be utilized for irrigation, landscaping, fisheries and wildlife protection, and more.
[0003] Fecal sludge is distinct from wastewater. It is more concentrated, contains higher levels of organic matter, and typically includes pathogens, nutrients, and solids. Managing fecal sludge effectively presents a variety of challenges. Safely removing sludge from sanitation systems without exposing workers or the environment to contamination is difficult. The lack of proper equipment and vehicles exacerbates this problem. Many urban areas lack adequate facilities to treat sludge, leading to unsafe disposal in water bodies, open land, or other inappropriate locations. Fecal sludge contains high concentrations of disease-causing pathogens such as bacteria, viruses, and helminths. Improper handling can result in outbreaks of diseases like cholera and diarrhea. Further, Untreated sludge can pollute surface water, groundwater, and soil, contributing to eutrophication, the spread of diseases, and contamination of drinking water sources. The collection and handling of fecal sludge are often seen as degrading work, leading to societal resistance and a lack of trained personnel. Developing countries often lack the financial resources to invest in FSM infrastructure, technologies, and workforce training.
[0004] Despite the increasing focus on fecal sludge management (FSM), implementing effective treatment strategies faces several challenges. These issues arise from technical, financial, institutional, and social factors, often creating significant barriers to sustainable sludge treatment. The primary problems associated with fecal sludge treatment strategies are inadequate infrastructure, financial constraints, lack of skilled workforce, inconsistent sludge characteristics, technical limitations of treatment technologies, poor integration with resource recovery, environmental and health risks etc.
[0005] Therefore, in order to avoid problems with the conventional techniques, there is a need for a low-cost, integrated faecal sludge treatment system that can solve problem with environmental pollution, costing, bacterial imbalance, heavy metals and radioactive substances present in purified water. The present disclosure is directed to overcome one or more limitations stated above, and any other limitation associated with the prior arts.
SUMMARY
[0006] One or more shortcomings of the prior art are overcome, and additional advantages are provided through the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
[0007] The present disclosure relates to a system for faecal sludge treatment. The system comprises a grit screening chamber, an anaerobic digestor, an anoxic tank, a collection tank, a collection tank, a first tube settler, a pair of moving bed biofilm reactor (MBBR), a second tube settler, a pressure sand filter, an activated carbon filter, and an effluent storage tank. The grit screening chamber is configured to pass through raw faecal sludge from an influent tank via a raw sewage inlet. The anaerobic digestor is subsequently placed with a raw water collection tank (106) that receives output of the grit screening chamber (104). The anoxic tank (110) is used for removing nitrogen compound from faecal sludge. The first tube settler is connected to the collection tank for separating settleable solids from the sludge, wherein the settleable solids drain to a sludge drying bed. The pair of moving bed biofilm reactor (MBBR) is connected to the first tube settler for decreasing biochemical oxygen demand (BOD) and chemical oxygen demand (COD) the organic matter present in the sludge. The second tube settler is coupled to other end of the pair of MBBR, configured to separate settleable solids from the sludge. The settleable solids of the second tube settler is drained to the sludge drying bed and residual water is drained to a filter feed tank. The pressure sand filter is coupled with the filter feed tank for removing contamination from the water using multi-layer filtration. The activated carbon filter is subsequently positioned to the pressure sand filter and is configured to absorb odours and absorbable pollutants from the residual water. The effluent storage tank is configured to store the treated water.
[0008] In another embodiment, the present disclosure relates to a method for treating faecal sludge. The method comprises the steps of passing raw faecal sludge through a grit screening chamber from an influent tank; digesting solid organic matter of faecal sludge with the help of microbial consortia and separating the solid and liquid part of sludge in an anaerobic digestor. The method includes removing nitrogen by using an anoxic tank arranged subsequently to the anaerobic digestor; and channelizing the residual portion through a first tube settler connected to the anoxic tank for aerobic treatment. The method further comprises passing the sludge through a pair of moving bed biofilm reactor (MBBR) where 50% to 80% of volume of air diffuser to decrease BOD and COD; and removing contaminants, odours and absorbable pollutants from the sludge by running through a pressure sand filter and an activated carbon filter respectively. The method involves ozonizing the processed sludge within a dozing ozonation tank for disinfection and storing the treated water in an effluent storage tank.
[0009] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0010] The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and regarding the accompanying figures, in which:
Figure 1 illustrates a diagrammatic representation of a system for faecal sludge treatment, in accordance with an embodiment of the present disclosure;
Figure 2 illustrates a work flow for faecal sludge treatment, in accordance with an embodiment of the present disclosure; and
Figure 3 illustrates a method for faecal sludge treatment, in accordance with an embodiment of the present disclosure.
[0011] The figure depicts embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0012] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.
[0013] While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the disclosure.
[0014] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non- exclusive inclusion, such that a setup, device or process that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or process. In other words, one or more elements in a system or apparatus proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
[0015] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
[0016] The proposed system for faecal sludge and septage treatment is relatively easy to construct and has greater ecological viability. The system is based on advanced hybrid system of anaerobic digestion and Moving Bed Biofilm Reactor (MBBR) based aerobic treatment. The system produces effluent quality that is significantly lower than the stipulated standard as mentioned by Central Pollution Control Board (CPCB) / Central Public Health and Environmental Engineering Organization CPHEEO). The process flow diagram of proposed technology is presented in Figure 2, wherein the diagrammatic representation of the system is illustrated in Figure 1.
[0017] As illustrated in Figure 1, the system comprises a grit screening chamber (104), an anaerobic digestor (108), an anoxic tank (110), a collection tank (112), a first tube settler (114), a pair of moving bed biofilm reactor (MBBR) (116-1, 116-2), a second tube settler (118), a pressure sand filter (122), an activated carbon filter (124), and an effluent storage tank (126). In one embodiment, the raw sludge passes through the grit screening chamber (104) from an influent tank via a raw sewage inlet (102).
[0018] The grit screening chamber (104) is a crucial component in a faecal sludge treatment system. The grit screening chamber (104) plays an essential role in ensuring the efficiency and longevity of the entire treatment process by removing grit and other coarse materials from faecal sludge. Grit, which typically includes sand, gravel, stones, and other solid particles, can cause significant wear and tear on downstream equipment and processes if not properly managed. The primary purpose of a grit screening chamber (104) is to separate heavy, inorganic materials from faecal sludge. These materials, often carried into the sludge through urban runoff or improper waste disposal, can compromise the performance of pumps, pipes, and treatment tanks by causing blockages and abrasion. By removing grit early in the treatment process, the chamber ensures smooth operations in subsequent stages, such as anaerobic digestion, drying, and composting.
[0019] A typical grit screening chamber is designed to take advantage of the density differences between grit and organic matter. Heavier inorganic materials settle at the bottom of the chamber due to gravity, while lighter organic components remain suspended and are carried further into the treatment system. The chamber consists of an inlet zone, a settling zone, and an outlet zone. By using the inlet zone faecal sludge enters the chamber. The flow is typically slowed down to allow settling. The settling zone is the primary area where grit and other heavy particles settle to the bottom. The outlet zone is the area where the organic-rich sludge exits the chamber for further treatment. Additionally, separating grit prevents environmental contamination. Proper grit removal ensures that the inorganic waste can be disposed of responsibly, minimizing the risk of polluting soil and water bodies.
[0020] The anaerobic digester (108) is a primary component of faecal sludge treatment systems (FSTS), playing a crucial role in the sustainable management of organic waste. The anaerobic digester (108) utilizes the natural process of anaerobic digestion – where microorganisms break down organic matter in the absence of oxygen – to treat faecal sludge. The process not only reduces the volume of waste but also produces valuable by-products like biogas and nutrient-rich sludge, making it an eco-friendly and efficient solution. In one embodiment, the anaerobic digestor (108) is subsequently placed with a raw water collection tank (106) that receives output of the grit screening chamber (104). The anaerobic digester (108) comprises microbial consortia for digesting solid organic matter of septage of the faecal sludge and separating the solid and liquid part of sludge. In one embodiment, the raw faecal sludge is retained within the anaerobic digestor (108) for a period up to 72 hours.
[0021] Anaerobic digestion is a biological process that occurs in a controlled environment within the digester. The process typically involves four stages i.e., hydrolysis, acidogenesis, acetogenesis, and methanogenesis. In hydrolysis, complex organic compounds such as carbohydrates, proteins, and fats are broken down into simpler molecules like sugars, amino acids, and fatty acids. In acidogenesis, microorganisms convert these simpler molecules into organic acids, alcohols, hydrogen, and carbon dioxide. In acetogenesis, the organic acids are further converted into acetate, hydrogen, and carbon dioxide. In methanogenesis, methanogenic microorganisms use acetate and hydrogen to produce methane (CH₄) and carbon dioxide (CO₂), which form the biogas. The anaerobic digester (108) is designed to provide optimal conditions – such as the absence of oxygen, controlled temperature, and sufficient retention time – for these processes to occur efficiently.
[0022] The anaerobic digester (108) for faecal sludge treatment includes an inlet chamber, a digestion tank, a biogas collection unit, and an effluent outlet. By using the inlet chamber, the faecal sludge is loaded into the digester. The digestion tank is a sealed, oxygen-free chamber where the digestion process takes place. The biogas collection unit captures the biogas produced during methanogenesis. The effluent outlet discharges treated sludge for further processing or reuse. Further, the anaerobic digestor (108) may comprise optional equipment to ensure uniform distribution of microorganisms and sludge within the tank.
[0023] One of the most significant outputs of the anaerobic digestor (108) is biogas, a renewable energy source composed primarily of methane. This gas can be used for cooking, electricity generation, or heating, contributing to energy sustainability. Anaerobic digestion significantly reduces the volume of faecal sludge, minimizing the burden on downstream treatment processes and disposal systems. The digested sludge is rich in nutrients like nitrogen, phosphorus, and potassium, making it a valuable fertilizer or soil conditioner for agricultural use. By capturing methane, the anaerobic digester (108) prevent the uncontrolled release of this potent greenhouse gas into the atmosphere, thereby reducing the carbon footprint of faecal sludge management. The digestion process can deactivate many pathogens, improving the safety of treated sludge for reuse or disposal.
[0024] The anoxic tank (110) is configured for removing nitrogen compound from faecal sludge. The anoxic tank is a vital unit in faecal sludge treatment system, particularly in processes that aim to remove nitrogen and other pollutants from sludge. Unlike aerobic digestor, the anoxic tank operates in environments without free dissolved oxygen, creating conditions favorable for specific microbial processes like denitrification. Such process contributes to the stabilization of faecal sludge, reduces its environmental impact, and prepares it for subsequent treatment or safe disposal. The anoxic tank is primarily designed to facilitate biological nitrogen removal through the process of denitrification. In faecal sludge, nitrogen often exists in the form of ammonia, which can lead to water pollution and eutrophication if released untreated. The anoxic environment enables denitrifying bacteria to convert nitrates (NO₃⁻) and nitrites (NO₂⁻) into harmless nitrogen gas (N₂), which is released into the atmosphere. The key process occurring in an anoxic tank is denitrification. Nitrates are typically supplied by recirculating effluent from nitrification tanks or by pre-treating faecal sludge in aerobic units where ammonia is converted to nitrate. Oxygen must be absent for denitrifying bacteria to thrive. Instead of oxygen, these bacteria use nitrate as an electron acceptor during metabolism. Organic matter in faecal sludge serves as the carbon source required for microbial growth and energy. The microbes break down the organic matter while reducing nitrates to nitrogen gas, completing the nitrogen cycle.
[0025] The design of an anoxic tank depends on factors such as the volume of faecal sludge, its composition, and the treatment objectives. Unlike aerobic tanks that use aeration, the anoxic tank relies on mixers to ensure uniform distribution of nitrates and sludge while preventing oxygen entry. Further, adequate hydraulic retention time is essential to allow complete denitrification. This varies depending on sludge characteristics and system capacity. In systems combining nitrification and denitrification, a recirculation mechanism ensures the movement of nitrates from aerobic tanks to the anoxic tank. The anoxic tank is designed to minimize oxygen infiltration to maintain an oxygen-free environment. The output of the anoxic tank (110) is collected at the collection tank (112).
[0026] Thereafter, the sludge of the collection tank (112) is passed through a first tube settler (114) for aerobic treatment. The first tube settler (114) is connected to the collection tank (112) for separating settleable solids from the sludge, wherein the settleable solids drain to a sludge drying bed (128). The first tube settler is an efficient device used in faecal sludge treatment systems to enhance the separation of suspended solids from liquids. Such sedimentation technique is especially valuable in compact systems where space is limited, as it optimizes settling processes without requiring large tanks. The first tube settler operates by providing a series of inclined tubes or channels where solid particles can settle more efficiently, making it a vital component for pre-treatment or secondary clarification in faecal sludge management. The primary function of the first tube settler is to accelerate the sedimentation process by increasing the settling surface area. Traditional sedimentation tanks rely on gravity to allow solids to settle at the bottom of the tank. The first tube settler improves this process by incorporating inclined tubes or lamella plates arranged at an angle (usually 60°). The first tube settler with oil and grease removal chamber where the settleable solids settle down in the bottom of the tube settler.
[0027] The first tube settler is designed to maximize efficiency while minimizing space requirements. Key components of the first tube settler include an inlet zone, a tube module, a settling zone, and an outlet zone. By using the inlet zone the faecal sludge enters the system. Flow distribution mechanisms ensure uniform loading across the tubes. The tube module consists of multiple inclined tubes or lamella plates. Such modules are usually made of lightweight, durable materials like PVC or polypropylene. The settling zone is a chamber below the tubes where settled sludge accumulates and is periodically removed. The outlet zone aids in flowing clarified liquid out of the system for further treatment or discharge. The modular nature of tube settler allows for scalability and easy installation in both small and large treatment plants.
[0028] The pair of moving bed biofilm reactor (MBBR) (116-1, 116-2) connected to the first tube settler (114), are configured for decreasing biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the organic matter present in the sludge. The Moving Bed Biofilm Reactor (MBBR) is an advanced wastewater and sludge treatment technique designed to effectively treat organic pollutants, nitrogen, and other contaminants. In the context of faecal sludge treatment systems, MBBR is increasingly gaining recognition for its ability to provide efficient treatment in a compact and energy-efficient manner. Such technology is especially well-suited for decentralized or urban treatment systems, where space and resources are limited. The MBBR is a type of attached growth biological treatment process where microorganisms grow on specialized carrier media that float freely in a tank. Microorganisms grow on the surface of the carrier media, forming a biofilm. Such biofilm is responsible for breaking down organic matter and removing nutrients like nitrogen and phosphorus. A reactor tank is continuously aerated or mixed (depending on whether it's aerobic or anaerobic), ensuring optimal contact between the biofilm and the faecal sludge. The carrier media provide a large surface area for microbial growth, significantly enhancing the treatment capacity of the reactor without increasing its size. The treated effluent exits the system through a sieve or screen that prevents the carrier media from leaving the reactor. By combining biofilm technology with suspended growth, MBBR provides an efficient, self-regulating process for treating faecal sludge. In one embodiment, the sludge is passed through MBBR tank 1 (116-1) where 50 to 80% of volume of air diffuser to decrease BOD and COD. In the next step the sludge may be passed through MBBR tank 2 (116-2) to decrease BOD and COD where 50 to 80% of volume of air is dosed by air diffuser.
[0029] The reactor tank is the main tank where the biological treatment occurs. The size and capacity of the tank depend on the volume and characteristics of the faecal sludge. Lightweight plastic elements with a high specific surface area are used as carrier media, designed to support biofilm growth. For aerobic MBBRs, an aeration system provides oxygen and keeps the carrier media in motion. In anaerobic MBBRs, mechanical mixing replaces aeration. A screen or sieve prevents carrier media from escaping while allowing treated water to flow out. Excess sludge produced during the process is periodically removed to maintain system efficiency.
[0030] The second tube settler (118) is coupled to other end of the pair of MBBR (116), wherein the second tube settler (118) is configured to separate settleable solids from the sludge. Further, the settleable solids of the second tube settler (118) drain to the sludge drying bed (128) and residual water drains to a filter feed tank (120). Each of the first tube settler (114) and the second tube settler (118) comprises array of inclined tubes (or plates) that provide a large surface area for particles to settle.
[0031] Thereafter, where the residual water drains to a raw water tank and the settleable solids drain to a sludge drawing bed. The treated water is then gathered in the filter feed tank and run through the pressure sand filter (122), which removes contaminants from the water using a multi-layer filtration technique. The purified water passes through the activated carbon filter (124), which absorbs odours and other absorbable pollutants. A pressure sand filter (PSF) is a widely used filtration system designed to remove suspended solids, turbidity, and other particulate impurities from water or wastewater. In the context of faecal sludge treatment system, PSFs are typically employed in the polishing stage of treatment, ensuring that the effluent meets quality standards for discharge or reuse. The pressure sand filter operates on the principle of mechanical filtration, where water or treated sludge is passed through a media bed (usually silica sand) under pressure. As the liquid flows through the filter bed, suspended solids and impurities are trapped within the sand layers, resulting in a clearer effluent.
[0032] Further, in a faecal sludge treatment system, activated carbon filters are typically employed in the final treatment stages to polish effluent, ensuring it meets discharge or reuse standards. Their ability to adsorb a wide range of contaminants makes them an indispensable tool for improving effluent quality. Activated carbon filters operate on the principle of adsorption, where contaminants adhere to the surface of porous activated carbon particles. The material is treated to develop an extensive internal surface area and high porosity, which enhances its capacity to trap pollutants.
[0033] In one embodiment, the system further comprises a dozing ozonation tank for ozonation of the output treated water of the activated carbon filter (124). The dosing ozonation tank is a treatment component in the faecal sludge treatment system that utilizes ozone (O₃) to disinfect, oxidize, and polish treated effluent. Ozone, a powerful oxidizing agent, effectively destroys pathogens, reduces odor, and breaks down organic and inorganic pollutants. The dosing ozonation tank is particularly valuable for achieving high effluent quality in situations where treated water is intended for reuse or discharge into sensitive environments. The dosing ozonation tank operates by injecting ozone gas into the treated effluent or faecal sludge in a controlled manner. Ozone is generated onsite, typically using an ozone generator, and dissolved into the water within the tank for effective treatment.
[0034] In one embodiment, the system (100) further comprises a sludge drying bed (128), wherein excess amount of water from the sludge drying bed (128) is transferred to the raw water collection tank (106) for further treating the excess amount of water so that less sludge is generated, and residual sludge is extracted to be dried for usage as manure. The sludge drying bed (SDB) is configured for dewatering and drying faecal sludge in the faecal sludge treatment system. The SDB is a simple, low-cost, and effective method for reducing the water content of sludge, making it easier to handle, transport, and further process or dispose of sludge. Sludge drying beds rely on natural processes, such as evaporation and drainage, to remove moisture from the sludge. Sludge drying beds operate by spreading sludge in a thin layer over a permeable bed. The water in the sludge is removed through two primary mechanisms i.e., drainage, and evaporation. In drainage free water from the sludge drains through the permeable layers of the drying bed into an underlying drainage system. Further, during evaporation, moisture in the sludge is evaporated into the atmosphere, driven by sunlight and air circulation. Over time, the sludge dries and forms a crusty, solid layer that can be manually or mechanically removed. The drying process depends on factors such as the thickness of the sludge layer, weather conditions, and the design of the drying bed.
[0035] Figure 2 illustrates a work flow for faecal sludge treatment, in accordance with an embodiment of the present disclosure.
[0036] As illustrated in Figure 3, the method 200 comprises one or more blocks for treating the faecal sludge. The order in which the method (200) is described is not intended to be construed as a limitation. Additionally, tertiary treatment units may be deleted from the methods without departing from the spirit and scope of the subject matter described herein according to the reuse requirement.
[0037] However, it is understood by a person skilled in the art that the size and configuration of the required set of machinery for accomplishing the method (200) may be variable in accordance with the requirement of the different types of installation environment. Any such variation/modification shall be construed to be within the scope of the present disclosure.
[0038] At block (202), raw faecal sludge is passed via a grit screening chamber. In one embodiment, the raw sludge passes through the grit screening chamber (104) from an influent tank via a raw sewage inlet (102). The grit screening chamber (104) plays an essential role in ensuring the efficiency and longevity of the entire treatment process by removing grit and other coarse materials from faecal sludge. The primary purpose of a grit screening chamber (104) is to separate heavy, inorganic materials from faecal sludge..
[0039] At block (204), solid organic matter is digested in an anaerobic digestor. In one embodiment, the anaerobic digester (108) utilizes the natural process of anaerobic digestion – where microorganisms break down organic matter in the absence of oxygen – to treat faecal sludge. The process not only reduces the volume of waste but also produces valuable by-products like biogas and nutrient-rich sludge, making it an eco-friendly and efficient solution. In one embodiment, the anaerobic digestor (108) is subsequently placed with a raw water collection tank (106) that receives output of the grit screening chamber (104). The anaerobic digester (108) comprises microbial consortia for digesting solid organic matter of septage of the faecal sludge and separating the solid and liquid part of sludge. In one embodiment, the raw faecal sludge is retained within the anaerobic digestor (108) for a period up to 72 hours.
[0040] At block (206), nitrogen is removed in an anoxic chamber. In one embodiment, the anoxic tank (110) is configured for removing nitrogen compound from faecal sludge. The anoxic tank is a vital unit in faecal sludge treatment system, particularly in processes that aim to remove nitrogen and other pollutants from sludge. Unlike aerobic digestor, the anoxic tank operates in environments without free dissolved oxygen, creating conditions favorable for specific microbial processes like denitrification.
[0041] At block (208), residual portion is channelized through a first tube settler. In one embodiment, the sludge of the collection tank (112) is passed through a first tube settler (114) for aerobic treatment. The first tube settler (114) is connected to the collection tank (112) for separating settleable solids from the sludge, wherein the settleable solids drain to a sludge drying bed (128). The first tube settler is an efficient device used in faecal sludge treatment systems to enhance the separation of suspended solids from liquids. The first tube settler operates by providing a series of inclined tubes or channels where solid particles can settle more efficiently, making it a vital component for pre-treatment or secondary clarification in faecal sludge management. The primary function of the first tube settler is to accelerate the sedimentation process by increasing the settling surface area.
[0042] At block (210), the sludge is passed through a pair of MBBR. In one embodiment, the pair of moving bed biofilm reactor (MBBR) (116-1, 116-2) connected to the first tube settler (114), are configured for decreasing biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the organic matter present in the sludge. The Moving Bed Biofilm Reactor (MBBR) is an advanced wastewater and sludge treatment technique designed to effectively treat organic pollutants, nitrogen, and other contaminants. In the context of faecal sludge treatment systems, MBBR is increasingly gaining recognition for its ability to provide efficient treatment in a compact and energy-efficient manner. In one embodiment, the sludge is passed through MBBR tank 1 (116-1) where 50 to 80% of volume of air diffuser to decrease BOD and COD. In the next step the sludge may be passed through MBBR tank 2 (116-2) to decrease BOD and COD where 50 to 80% of volume of air is dosed by air diffuser.
[0043] At block (212), the sludge is run through a pressure sand filter and an activated carbon filter. In one embodiment, the residual water drains to a raw water tank and the settleable solids drain to a sludge drawing bed. The treated water is then gathered in the filter feed tank and run through the pressure sand filter (122), which removes contaminants from the water using a multi-layer filtration technique. The purified water passes through the activated carbon filter (124), which absorbs odours and other absorbable pollutants. A pressure sand filter (PSF) is a widely used filtration system designed to remove suspended solids, turbidity, and other particulate impurities from water or wastewater. Activated carbon filters are typically employed in the final treatment stages to polish effluent, ensuring it meets discharge or reuse standards. Their ability to adsorb a wide range of contaminants makes them an indispensable tool for improving effluent quality.
[0044] At block (214), the residual is ozonized and stored as treated water. In one embodiment, in one embodiment, the system further comprises a dozing ozonation tank for ozonation of the output treated water of the activated carbon filter (124). The dosing ozonation tank is a treatment component in the faecal sludge treatment system that utilizes ozone (O₃) to disinfect, oxidize, and polish treated effluent.
[0045] The proposed system is much less expensive to operate and maintain than existing technologies, and it requires very little maintenance. Comparing the system to other technologies, it takes up a lot less space. The system is designed to be modular and may be customised based on the site's needs. By robustly maintaining an improved effluent (solid and liquid) quality, the system protects the environment. The sludge handling facility is much reduced because of the extremely low stabilised sludge volume. Digested sludge's quality guarantees that it can be used as high-grade manure. The purified water generated after the treatment may be used in the agriculture, industrial and domestic construction work, animal husbandry etc. Further, the dried sludge will be used as manure. The system can reduce indiscriminate disposal of collected faecal sludge. As the treatment is based on effective microbial consortia, it can turn faecal sludge into a useful product with environmental and economic benefits with a very short duration. The system stabilizes organic matter contained in the sludge. The system aids in disposal of sludge in a safe and aesthetically acceptable manner which in turn prevent harmful diseases.
[0046] The major advantage in the present invention lies in its efficacy, cost effectiveness and less area intensive arrangement. The proposed system overcomes various difficulties in treating the fresh faecal as well as mineralized faecal and supernatant individually to the desired standard. The system is modular and compact. So, it can be scaled up to any extent as well as scaled down depending on the requirement. The system does not create any surrounding environmental nuisance and the treated supernatant is aerated and it can be reused with specific tertiary treatment after the patented module. The system can be attractive to many government and private agencies and also in the research arena as it has a promising future for installation in rural, urban or mega cities.
[0047] In the detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The description is, therefore, not to be taken in a limiting sense.
Equivalents:
[0048] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
[0049] It will be understood by those within the art that, in general, terms used herein, and especially in the 3 claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations.
[0050] In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
[0051] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims. , Claims:We Claim:
1) A system for faecal sludge treatment, the system comprises:
a grit screening chamber (104) configured to pass through raw faecal sludge from an influent tank via a raw sewage inlet (102);
an anaerobic digestor (108) subsequently placed with a raw water collection tank (106) that receives output of the grit screening chamber (104);
an anoxic tank (110) for removing nitrogen compound from faecal sludge;
a collection tank (112);
a first tube settler (114) connected to the collection tank (112) for separating settleable solids from the sludge, wherein the settleable solids drain to a sludge drying bed (128);
a pair of moving bed biofilm reactor (MBBR) (116-1, 116-2) connected to the first tube settler (114), for decreasing biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the organic matter present in the sludge; and
a second tube settler (118) coupled to other end of the pair of MBBR (116), configured to separate settleable solids from the sludge, wherein the settleable solids of the second tube settler (118) drain to the sludge drying bed (128) and residual water drains to a filter feed tank (120);
a pressure sand filter (122) coupled with the filter feed tank (120) removes contamination from the water using multi-layer filtration;
an activated carbon filter (124) subsequently positioned to the pressure sand filter (122) configured to absorb odours and absorbable pollutants from the residual water; and
an effluent storage tank (126) configured to store the treated water.
2) The system (100) as claimed in claim 1, wherein the system further comprises a dozing ozonation tank for ozonisation of the output treated water of the activated carbon filter (124).
3) The system (100) as claimed in claim 1, wherein the raw faecal sludge is retained within the anaerobic digestor (108) for a period up to 72 hours.
4) The system (100) as claimed in claim 1, wherein the anaerobic digester (108) comprises microbial consortia for digesting solid organic matter of septage of the faecal sludge and separating the solid and liquid part of sludge.
5) The system (100) as claimed in claim 1, wherein each of the first tube settler (114) and the second tube settler (118) comprises array of inclined tubes (or plates) that provide a large surface area for particles to settle, wherein the first tube settler (114) comprises oil and grease removal chamber where the settleable solids settle down in the bottom of the first tube settler (114).
6) The system (100) as claimed in claim 1, wherein excess amount of water from the sludge drying bed (128) is transferred to the raw water collection tank (106) for further treating the excess amount of water so that less sludge is generated, and residual sludge is extracted to be dried for usage as manure.
7) A method (200) for treating faecal sludge, the method comprises:
passing (202) raw faecal sludge through a grit screening chamber (104) from an influent tank;
digesting (204) solid organic matter of faecal sludge with the help of microbial consortia and separating the solid and liquid part of sludge in an anaerobic digestor (108);
removing (206) nitrogen by using an anoxic tank (110) arranged subsequently to the anaerobic digestor (108);
channelizing (208) the residual portion through a first tube settler (114) connected to the anoxic tank (110) for aerobic treatment;
passing (210) the sludge through a pair of moving bed biofilm reactor (MBBR) (116-1, 116-2) where 50% to 80% of volume of air diffuser to decrease BOD and COD;
removing (212) contaminants, odours and absorbable pollutants from the sludge by running through a pressure sand filter (122) and an activated carbon filter (124) respectively; and
ozonizing (214) the processed sludge within a dozing ozonation tank for disinfection and storing the treated water in an effluent storage tank.
8) The method (200) as claimed in claim 7, the method further comprises:
transferring excess amount of water from a sludge drying bed (128) is to a raw water collection tank (106) for further treating the excess amount of water so that less sludge is generated, and
extracting residual sludge from the sludge drying bed (128) where the extracted residual sludge is dried for usage as manure.

Dated 29th day of March 2025.