ES2301370A1 - Equipment for biological purification of wastewater - Google Patents

Abstract

The equipment is configured as a single digester for performing hydrolytic and methane-generating anaerobic digestion and purifying wastewater, which improves habitat compatibility between bacteria, optimizing appropriate ecological niches and creating a new habitat in which nitrogen-reducing bacteria are formed. The equipment is formed by a body with two concentric walls (1) and (2), forming an internal body in which there are ceramic pieces (8) where anaerobic digestion of the water takes place by means of ascent through said ceramic block (8), whilst, at the perimeter, there is a chamber (5) with a lower compartment (6) where methane-generating digestion takes place, all this with conduits (19') and (24) for the recirculation of water towards a new digestion receptacle and conduits for the discharge of gases (29), and also a lower outlet (17) for sludge.

Description

Equipment for biological water purification residual

Object of the invention

The present invention relates to an equipment of Biological wastewater purification, where the purification is based on anaerobic, hydrolytic, fermentative, acid digestion gene and methanogenic, presenting the particularity of be configured as an anaerobic digestion equipment that includes a only digester in which, according to an appropriate design of the same, the corresponding ecological niches are optimized, creating a new habitat in which bacteria reduce the formation of nitrogen.

The team has its application within the industry dedicated to urban wastewater treatment or industries that need to purify water with high contents in organic matter, especially sludge disposal primary from water purification plants with aerobic systems

Background of the invention

In the processes of biological purification of wastewater with high organic load, whether from cities (urban wastewater) or industries agro-food, livestock farms in housing regime in which large quantities of  slurry (bowel movements, livestock feces formed by solids and  liquids), etc., anaerobic digesters or reactors are used, being able to be of a single digester without phase separation, or high speed with phase separation.

In single digester systems, they are accumulation reactors with a hydraulic residence time that It ranges between 15 and 21 days, so that during the process solids larger than 1 millimeter are usually separated contained in the water, before the entry of liquid into the anaerobic digester They are also known as DAC type of core activity

Anaerobic bed reactors are also known fixed or mobile that can be divided into the following systems:

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Up anaerobic sleugde blanker flower (UASB)

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Fluid bed or bed reactor expanded (BIOFLUID system)

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Fixed bed reactor with support plastic or ceramic fixing bacteria.

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Anaerobic filters

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Two phase reactors.

The contact reactor is a unique reactor that It has devices for internal agitation. how are the injection of the gas itself produced to improve the mixture of biomass in the digester and stir the liquid inside itself digester, achieving a reduction of residence times hydraulics.

However, the concentration of different types of bacteria within a single digester destabilizes the process, due to the increase of a colony of bacteria with respect to the other or others, it also destabilizes the pH within the digester, very often the clogging of this type of digesters.

In addition, there is a loss of performance in the purification, as well as low biogas production. By consequently, it is an essential point for the process that the Bacterial balance of biomass for the same organic load be digested at different times by bacteria gene-acids (hydrolytic, fermentative) and methane genetics (acetoplastics e hydrogen-rows). For this reason the increase of a population in the hydrolysis phase entails a decrease in methanogenic bacteria causing destabilization of process, losing efficiency, not being able to eliminate organic components of the residue to be treated in a suitable time, all due to the different reproduction rate of the bacteria

In the same way the activity system central (DAC), although it improves the performance of the contact reactor with an internal decanter that ensures a higher concentration of bacterial biomass inside and facilitates the precipitation of easily settable inert materials, does not solve the problem of cohabitation of bacteria with habits demands counterposed, so your debug times or time of hydraulic residence for the purification of, for example forty cubic meters of water a day, which requires a volume of the digester of approximately 500 cubic meters, it would be twelve and a half days, with 80% purification efficiency for the chemical demand of oxygen, and 95% for the biological oxygen demand.

This system entails building large digesters with high capacity volumes to treat volumes low sewage, etc., so that economic investment It is high to treat low purification flow rates.

The UASB system improves performance, thanks to greater granulation of anaerobic biomass and the use of sludge bed, although the differentiation of bacteria habitats, not looking at the different rates of reproduction or in setting a neutral pH from the phase hydrolytic, so it easily destabilizes with substantial variations of the organic load to be treated, altering substantially system performance.

Fluidized bed or bed reactors expanded, are acceptable in terms of fixing bacteria, especially methanogenic, at include micronized silicate or plastic supports in the process of different densities, highlighting among them the system known as the fluid bed reactor or expanded bed, in where anaerobic digestion performance is increased, improving the adequacy of digester volumes.

It also achieves a reduction in concentration of carbon dioxide in the reactor liquid, simplifying the temperature control in the process by use of easily fluidized supports, reducing electrical consumption and favoring the development and selection of bacteria depending on the wastewater to be treated. This type of Systems is widely used in the beer industry.

Also the anaerobic filters that improve, according to the support used, the fixation of bacteria, creating a film around the spheres or balls, rings, built by plastics of different densities and configured within the tanks randomly or modularly, being able to be fed with flow vertical (up-flow AF or down-flow DSFF). There are also two-phase reactors in which in a single expanded bed reactor join the hydrolytic phase operated by a DSFF reactor and the methane gene, this set constituting a high speed reactor that considerably reduces the time of Hydraulic residence, and bacteria habitat, reaching Good rates of performance and efficiency.

They can also be commented and are significant works of IZA, COLLERAN and others.

In Spain FIESTAS J. A. developed reactors anaerobic for the purification of industrial wastewater and urban, in the year 1996.

In any case, any of the systems commented present the inconvenience of not having resolved the maximum nitrogen removal in the hydrolytic phase and subsequent removal of the remaining nitrogen in the phase methane gene, as well as the good fluidization of the silicates used for fixing bacteria.

However, the applicant has systems protected in corresponding patents in which the habitat for the compatibility of bacteria, solving the pH stabilization from the hydrolytic digester, although based The previously used points remain unresolved commented.

Description of the invention

The equipment for biological water purification Residual object of the invention solves the problems referred to in the previous section, achieving a substantial improvement in the decrease in hydraulic residence times, as well as the debugging capacity for high organic loads, with maximum reduction of ammoniacal nitrogen and a reduction in cost economic, to include a single digester, with the consequent decrease of components, such as pumps, valves, heat exchangers, etc.

More specifically, the team of the invention is configured as a team of multiple anaerobic digestion, for the Biological wastewater purification with anaerobic digestion hydrolytic and methanogenic, solving the incompatibility between bacteria, optimizing the different niches ecological in the same reactor and improving the pH stability in the hydrolytic phase, by means of a new substrate used; how is the calcined atapuljita mixed with clays containing in its sepiolite chemical composition so that they can be kneaded, to then form rectangular pieces in the shape of vaults ceramics that are normally used in construction, so such that the placement of these pieces in the digester correspond to a distribution in square or rectangular form, preventing the clogging of the channels through which water circulates, determining sufficient contact surface for fixing bacteria between 6 and 10 square meters of surface area per cubic meter of inlet water. Preferably, the height of the ascending channels is set to a minimum of two and a half meters up height.

The size of the reactor or digester of the equipment the invention is defined by the sum of retention times hydraulics of the different phases and according to the growth or better lifetime of bacteria than for bacteria Hydrolytic, acid-gene and fermentative is of three days and for the methano-gene is thirty hours.

The feeding of said digester is done by the lower part with a conduit or tube, forming a ring of distribution inside the digester to distribute proportionally the incoming flow through all channels ascending that form the ceramic placed inside, being the effluent driven inwards by a flow pump variable type mono, or rotor and stator.

The water that comes out at the top of the digester, through a tompson channel, falls into a chamber or perimeter or outer compartment of the digester, from which that water is sent by a variable flow pump, through the corresponding conduit, to the bottom of the commented perimeter compartment, whose bottom and externally goes located a distribution ring with some entrances to the compartment, establishing in each of the entrances a venturi nozzle for good silicate expansion in the inside the commented compartment, with the particularity that it is isolated from the inside of the digester and is in communication only with a gas storage hood established superiorly, whose communication between compartment and gas storage hood is made using tubes that communicate the commented top of the compartment or chamber with the repeated gas accumulation bell.

On the other hand, at the top of the commented bell is planned a circular opening that is prolongs upwards according to a cylindrical configuration, concentrically to which and externally there is another cylindrical neck, and between both cylinders a bell is arranged to inverted bowl mode whose side and circular wall is arranged between the two commented cylinders, bowl that presents a hole in which a conduit is connected for the output of gas, establishing a water tight seal between the two commented concentric and superior necks with the bowl inverted housed inside and between them.

The whole digester is also complemented with opening and closing valves, as well as level probes, a ring diffuser in correspondence with the top and externally to ceramic core, and a conical bottom bottom with an outlet of sludge discharge.

Description of the drawings

To complement the description that is being performing and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical realization of it, is accompanied as part member of that description, a set of drawings where with illustrative and non-limiting nature, what has been represented next:

Figure 1.- Shows a simplified view and according to an elevation of the biological water purification equipment Residues with anaerobic digestion, object of the invention.

Figure 2.- Shows a sectional view. corresponding to the A-A cutting line of the previous figure.

Preferred Embodiment of the Invention

As you can see in the referred figures, the equipment of biological purification object of the invention presents the general shape of a cylindrical body configuring a single digester with two concentric walls, one exterior (1) and one interior (2), being shaped superiorly, as an extension of the wall exterior (1), a closing bell (3), and as a lower closure, in correspondence with the inner wall (2), a closing bell bottom (4), both bells (3) and (4) being configured conical

Between the concentric walls (1) and (2) of the digester a chamber (5) prolonged inferiorly is established in a compartment (6), closed by the bottom according to a conical configuration (7).

In the inner body established by the wall (2) a block of ceramic pieces (8) is arranged, presenting these form of vaults, with a quadrangular arrangement or rectangular as shown in figure 2, the assembly being of ceramic pieces (8) supported by joists (9), below which and at a certain distance from them, has provided a distributor ring (10) and in correspondence with the general inlet duct (11), all in a way that by a pump impeller or any other system, the water to try is passed upwards through the whole ceramic (8), to produce the aerobic process correspondent.

Centrally, the top closing bell (3) it has an opening delimited by a cylindrical neck (12), which it is complemented with another exterior and concentric (13), and between both a kind of inverted bowl (14) whose upper base is connected to a gas outlet duct (15), in which it has provided a shut-off valve (16) and the corresponding flange of coupling

Between the cylindrical necks (12) and (13) are establishes an annular channel that is filled with water, leaving the inverted bowl (14) inside and setting in that part upper a tight seal.

That is, by arranging the necks cylindrical and concentric (12) and (13), a channel or annular receptacle that fills with water to cover with the bowl inverted (14), equipped with a single output to which it is connected the conduit (15), determining a perfect hydraulic seal, being able to give the pressure that is required for optimum growth of the bacteria, pressure that is regulated by providing more or less weight on the top of the inverted bowl (14), being able to consider the optimum working pressure to be between 300 and 400 millimeters of water column.

For its part, the lower closing bell (4) it has a central and lower output (17) in functions of decanter, to which a conduit or tube (18) is connected, with a manual valve for sludge discharge, that is, biosolids digested, which are mostly made up of minerals not biodegradable

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As for the height of the ceramic pieces (8), which are arranged in layers as represented in the Figure 2, will be determined by the BOD of the water that has to be debug, taking into account that a square meter of surface area of contact contains at least two to three kilograms of biomass or bacteria adhered to said surface, taking into account that each ceramic piece has a contact surface of two meters and half squares, supporting between five and seven kilograms of biomass or attached bacteria, each kilogram of bacteria that support the ceramic pieces will consume twice their weight in organic matter for normal development and growth, defining in this way the number of ceramic pieces (8) that It forms the contact surface inside the digester.

The ceramics used in its chemical composition it must contain at least 40% atapuljita, and be as porous possible, which will be given by the microscopic laminar structure where hydrolytic bacteria can be introduced and removed easily to eat and not be swept away upward functioning of the digester.

Likewise, say that said type of pottery influences the digester's pH stabilization, so that the power up influences the best performance of the digester, improving the stabilization of the process and diminishing the hydraulic retention time in the phase methane gene

Above all the ceramic pieces (8) a conduit or tube (19 ') provided in correspondence is located with the feed inlet duct (19), in which it has provided a valve, with the particularity that the duct (19 ') goes outside the general body of the digester and connects with the distribution ring (10), so that through a pump (21) is made to recirculate the effluent, which has only passed by the ceramic assembly (8) and decanted by the distance that separate the inlet of that tube (19 ') from the upper water outlet towards the outside of the digester.

Above the block of ceramic pieces (8), a tompson channel (22) of overflow and exit of the water to the inner part of the chamber (5), water that falls from a height determined, whose distance is controlled by a level probe (23), so that when it exceeds a preset level the corresponding PLC associated with the equipment orders the pump to stop corresponding feed, all in a way that distance is necessary to be able to degas the water and that this does not pass the part of the lower compartment (6) with high gas contents

In the commented chamber (5) of the digester, it is where the hydrolytic phases are carried out and acid-gene, having as its only limitation the water fall height, since the other variables (width and height) They will be sized according to the water flow to be treated per day.

From the chamber (5) referred to above, water exits from the bottom of the compartment (6) through the tube or conduit (24), said water being driven by a pump (25), all this in a way that in correspondence with the party Conical bottom (7) of the compartment (6) referred to, are provided nozzles (27) that produce a venturi effect and that are separated equiangularly with each other, that is equidistant in a circular contour corresponding to the outer tube (28) provided e inferiorly through which the water coming from the upper chamber (5) of the hydrolytic digester gene-acid, by impulsion of a pump variable flow feed used to fluidize the silicate and keep it in suspension, so that the silicate that It is used for fixing bacteria in the digester should have a specific grain size and a specific weight something higher than water, while the burned attapuljita also of these two qualities must have a molecular structure fibrous Where methanogenic bacteria are fixed, the colonization of particles, forming clusters and detaching methane gas by synthesizing matter in its diet organic

In the upper part of the compartment (6), in the one that performs the methanogenic digestion and in correspondence with all the circular perimeter, tubes (29) are placed, separated equiangularly to each other, whose function is L to serve as means for the extraction of the gas produced in the compartment (6) and drive it, for storage, to the top (30) determined by the upper bell (3).

In the tubes or ducts (19 ') and (24), in the that the discharge pumps (21) and (25) are interleaved respectively, the corresponding valves are provided manual and pneumatic (31), also shown in Figure 1 temperature probes (32), water level signaling (33) and an outlet (34) for the methanogenic, whose output is provided in the compartment (6), as well as a level probe (35) in it latest.

In the upper part (30) a level of contact that determines the maximum filling volume of the digester, that contact level being connected to the corresponding PLC operating order that closes the corresponding pneumatic valves and therefore the shutdown of the pumps food (21) and (25), both the input to the internal digester as to the outside digester.

As for the wastewater or purified effluent, will lower by gravity to the decanter (17) established in the part bottom of the bell (4), a decanter that is lamellae, with a hydraulic retention time determined by quantity of solids containing the purified effluent and the speed of decanting, so that said solids or sludges produced in the Decanting is incorporated into the input or recirculation circuit sludge (19) from the hydrolytic digester using a type pump mono, connected by the lower part of the decanter, leading them to the feed pipe (19) of the digester to digest them again. These biosolids are organic matter being formed largely by dead bacteria, serving as food to the bacteria fixed in the hydrolyte when introduced by the upper part of the fixing parts, forming a current descending and slow that improves the growth of the biomass jijada, being thus digested and becoming part of the biosolids that they are removed through the duct (17) of the decanter. In the part top of the decanter a connection (20) is provided for clean water outlet.

Regarding the constitution of the digester referred to, the fiberglass can be used as a material, virilester, iron, stainless steel or even concrete, this last properly painted inside with resins epoxy

The equipment is complemented with a deposit (36) with a decanted water outlet (37), a sludge outlet (38) for recirculation through the feed duct (19) and the inlet (39) of water to be decanted and that constitutes the product metallogenic from the exit (34), counting that deposit (36) with baffles (40), as clearly represented in figure 1.

It should be said that the digester as a whole is Heated with thermal blanket or projected polyurethane in all its outer perimeter to achieve the lowest heat loss due to its outside and keep a temperature inside optimal for the growth of bacteria, temperature that can get by using exchangers external market heat.

The whole team will be controlled by the PLC, which receives information on the levels, the probes of temperature, pH and Redox, programmed to stop and put into pump run, valve opening and closing and control of temperature.

Claims (6)

1. Equipment for biological purification of wastewater, which being planned to perform an anaerobic hydrolytic, fermentative, gene-acid and methano-gene anaerobic digestion, constituting itself through a single digester, is characterized in that it comprises a cylindrical general body with an outer wall (1 ) and an inner wall (2), determining an internal part for the arrangement of ceramic pieces (8) through which the water to be treated flows upwards, with an inlet (11) that flows into diffusers (12) provided inferiorly to this block of ceramic pieces (8), with the particularity that between both walls (1) and (2) a chamber (5) with a lower compartment (6) is determined where methanogenic digestion takes place; with the particularity that a duct or tube (19 ') associated with a diffuser ring (10') in communication with the feed inlet (19), through whose tube is provided superior to the block of ceramic pieces (8) or conduit (19 ') the water is recirculated to the diffusers (10) provided under the block of ceramic pieces (8), while between the perimeter chamber (5) and the bottom of the compartment (6) in which said chamber (5), a conduit or tube (24) is provided that communicates with a perimeter, external and inferior conduit (28), with small tubes that are finished off in internal nozzles (27) of the lower part (7) of the compartment (6), it being provided that both pumps (21) and (25) are inserted in both the duct (19 ') and the duct (24) to drive the effluent to the diffusers (10) located under the ceramic block (8), as to the bottom of the compartment (6); with the particularity in addition that in the upper part a water overflow channel (22) is included for the gravity fall towards the outer and perimeter chamber (5), in which gas outlet ducts (29) are provided, the evacuation being established outside through a conduit (15) provided in the top or upper base of an inverted bowl (14) located in an annular channel established between two cylindrical necks (12) and (13) provided in correspondence with an outlet upper and central of an upper closing bell (3). 2. Equipment for biological purification of wastewater, according to claim 1, characterized in that between the concentric necks (12) and (13) established in the upper opening of the chamber (30) determined by the upper closing bell (3), determines a tight seal in combination with the inverted bowl (14), by filling the annular channel with water between said two concentric necks (12) and (13). 3. Equipment for biological purification of wastewater, according to previous claims, characterized in that the ceramic pieces (8) have a chemical composition with an attapulgite content of at least 40%, being their laminar and porous microscopic structure to facilitate the transfer of the hydrolytic bacteria without being dragged by the updraft through such ceramic pieces (8), with the particularity that the block that forms these, in a quadrangular or rectangular arrangement, is supported by a series of beams (9). 4. Equipment for biological purification of wastewater, according to previous claims, characterized in that the lower closure of the body of the digester, and specifically the internal and concentric cylindrical body, is materialized by a bell (4) with an outlet (17) for settling of sludge, for evacuation, through a conduit (18), to the outside. 5. Equipment for biological wastewater purification, according to previous claims, characterized in that the ducts of the set include corresponding valves (31), manual and pneumatic, while the equipment includes level probes (23) and (35) as well as an outlet methane gene (34) and temperature probes (32). 6. Equipment for biological wastewater treatment, according to previous claims, characterized in that the assembly is related to a PLC for control and control of all components and the correct functioning of the equipment.