ES2325349B2 - PROCEDURE AND SYSTEM FOR THE TREATMENT OF WATER CONTAMINATED WITH HEAVY METALS. - Google Patents

Abstract

Procedure and system for the treatment of waters contaminated with heavy metals.

The procedure includes the extraction of heavy metals in contaminated water, usually from of industrial processes, through the trapping activity biological that develops the mycelium of the fungus. This mycelium of fungus is present in the substrate used in the cultivation of Mushrooms or other edible mushrooms. The invention is also refers to a system for carrying out said procedure.

Description

Procedure and system for the treatment of waters contaminated with heavy metals.

The present invention includes a method for the treatment of water contaminated with heavy metals, since be these coming from industrial or communal discharges, water contaminated drinking water, infiltration water or aqueous waste special. This refers to a metal extraction system heavy in water, usually from processes industrial, through the activity of biological entrapment that develops the mycelium of the fungus present in the substrate used in the cultivation of mushrooms or other fungi.

       \ vskip1.000000 \ baselineskip
    

Prior art

Hazardous pollutants contribute to there is a growing number of chronic ailments, such as cancers and heart disease. Chemical contaminants they can also play a role in infectious diseases, perhaps leaving the body more vulnerable to infections.

Among those types of hazardous pollutants are that include heavy metals, and more specifically the waters contaminated with dissolved heavy metals. The toxicity of these metals has been documented throughout history: doctors, both Greek and Roman, diagnosed symptoms of acute lead poisonings long before toxicology It became science. Currently much more is known about effects of heavy metals, whose exposure is related to developmental delays, various types of cancer, damage to the kidney, and even with cases of death when exposure has been excessive

For ecological and economic reasons, the general environmental situation requires the availability of substances economic filters for industrial water purification dirty or special aqueous waste.

The high quality activated carbon that used in filters for water purification with metals heavy is too expensive, besides it can only be regenerate partially, as harmful organic substances they are linked by absorption and therefore cannot be unclog completely. In addition, carbon filter fillings activated are decompacted as a result of mechanical loads destroying its porous structure, so in part they lose their defined effect of absorption, adsorption and chemisorption. In in this case harmful substances can be released so after their saturation generally require thermal removal.

On the other hand, compositions have been described for the treatment of contaminated water in which the mushroom depleted compost (SMS) is found together with other active components such as bacteria (cf. EP983970) for the elimination of organic components or in admixture with carbonate calcium and hydrated fly ash (cf. " Mine drainage treatment wetland substrate analysis ", Athay D. Nairm RW and Strevett KA, Wetlands Abstracts; Billings Land Reclamation Symposium, 2003) being its field of application the treatment of swampy land, and so that the precipitation of metals is based on the increase in the pH of contaminated water.

       \ vskip1.000000 \ baselineskip
    

Explanation of the invention.

The authors of the present invention include a procedure for the treatment of water contaminated with metals heavy and at any pH. This procedure is based on employment, as the only debugger element of the compost containing mycelium of fungus, and more particularly of compost depleted of the cultivation of mushroom, from the cultivation of other fungi or any compost mixture depleted of different crops.

This compost can be the residue directly obtained from the mushroom or other mushroom growing plant, it is say, no need for any type of treatment for your use in the treatment of water contaminated with metals heavy

The objective of the present invention is to ensure a low cost process, both execution and maintenance, that allows to transform the load of heavy metals into cargo organic much easier to treat, being valid interchangeably for contaminated water with a very high pH (pH> 12) as with a pH very low (pH <2), so that the residual material of the mushroom production also becomes a factor in recovery of that residue.

To do this, and as mentioned above, the procedure consists in taking advantage of the residues from the cultivation of mushrooms or other edible fungi, specifically through the activity of biological entrapment developed by the mycelium of the fungus present in the substrate used in said crops of Agaricus bisporus or mushrooms, usually called "Spent Mushroom Substrate" or SMS, or the cultivation of other fungi.

This substrate that is used for said purpose, it is used once the planned product floats, that is, when considered sold out or "used".

The present invention includes a method for the treatment of water contaminated with heavy metals (in hereinafter method of the invention) comprising passing the water for at least one bioreactor containing compost with mycelium of fungus.

By "heavy metals" is meant a group of chemical elements that have a relatively density high and certain toxicity to humans. Like for example, but without being limited to the group comprising metals such as aluminum, arsenic, barium, beryllium, cadmium, cobalt, copper, chromium, tin, iron, manganese, mercury, molybdenum, nickel, silver, lead, Selenium, thallium, vanadium or zinc.

In a preferred embodiment of the present invention, the compost is a substrate used in the cultivation of Agaricus bisporus (mushrooms), other edible fungi, such as, for example, Lentinula edodes (Shiitake or Japanese fungus), Ganoderma lucidum (Reishi), species of the genus Pleurotas , such as Pleurotus eryngii (gargoyles), Pleurotus ostreatus (Mushroom Fungus), etc ..., or any mixture of depleted substrates of different crops.

To carry out the procedure described, has planned an installation that is constituted from a series of debug tanks containing congruent cells of depleted compost of mushroom (SMS), or other edible mushrooms, which they can be arranged in series in the direction of the flow of water to treat, and capable of removing heavy metal quantities of broad spectrum through the action of the mycelium of the mushroom or others fungi, which causes the generation of heavy metal sulphides and, therefore, its withdrawal from the flow of water, settling between tank and tank the corresponding pumping system hydraulic.

Similarly, and due to the high content in compost carbon, this provides usable carbon for feed the oxidation of metals in the aerobic zone, forming heavy metal oxides in solid form that are removed from treated water.

Thus, the present invention also includes a system for carrying out the process of the invention, which It comprises at least one depuration tank. Each one of these deposits can contain one or more cells with mycelium compost Mushroom More preferably, these cells contain substrate exhausted from mushroom cultivation (SMS), from other edible mushrooms or of any of its mixtures.

According to one aspect of the invention the system comprises open debug tanks superiorly. Such deposits may include a water inlet in its lower zone and a filtered water outlet also in the area lower but opposite of the depuration tank.

In a preferred embodiment of the system of the present invention, the depuration tanks are connected in series in the direction of the water flow to be treated.

The number of debug tanks is going to depend on the pollutant load and the nature of the metal to remove.

When a debug tank contains two or more cells, an intermediate wall of smaller height is incorporated than the reservoir to separate cells and force a water flow ascending-descending through them, also having the filtered water outlet in the area lower and opposite to the water inlet of the tank.

The system of the invention allows, in case of interest, recirculation or the unique flow of a natural nature or forced, including means of retaining cell contents so that the reverse flow of water prevents buoyancy of the same.

A more preferred embodiment of the system of the The present invention also comprises at least one deposit for the water contaminated with heavy metals, connected to the entrance of the depuration tank, and at least one accumulation deposit of the purified water at the outlet of the purification tank.

In case there is not enough slope between the deposits to allow the circulation of water through gravity along the entire water treatment circuit, the system of the invention can have a pumping system hydraulic.

Consequently, and thanks to the structuring of the installation, the load can be variable according to the number of compost deposits used as well as the size of same.

Also noteworthy is the fact that the cited cells in which the compost is stored may be equipped with an anchor system, which allows cells Shaped can be easily replaced during operation of filtering, for later management.

Another preferred embodiment of the system of the present invention, in the case of natural unevenness in the field in which the installation of the invention is implanted and that it lacks the aforementioned hydraulic pumps, includes the use of these unevenness, optimizing the system of water treatment, as well as its assembly process, with the consequent advantages that this supposes.

Experimentally it has been proven that the procedure of the invention is effective both with waters that have a low pH as water with a high pH, since the pH modification is a consequence of the bioremediation process made by the mycelium of the compost fungus, which presents a pH close to neutral.

In this way a system of treatment of heavily contaminated water with heavy metals simple, low cost and modular, which allows use of waste from the cultivation of Mushrooms or other mushrooms.

Given the modular design of the system, it can function even when one of the cells is not installed or is being replaced It also eliminates the need for recirculation of the fluid with the consequent cost of pumping.

Throughout the description and the claims the word "comprises" and its variants not they intend to exclude other technical characteristics, devices, components or steps. For those skilled in the art, other objects, advantages and features of the invention will be partly detached of the description and in part of the practice of the invention. The following examples and drawings are provided by way of illustration, and are not intended to be limiting of the present invention.

       \ vskip1.000000 \ baselineskip
    

Brief description of the figures

Fig. 1.- Shows a side elevation view of a laboratory bioreactor used to calibrate the functionality of the process of the invention.

Fig. 2- Shows the evolution of the load pollutant in water for different solutions and contaminants in a laboratory experience performed. On the axis vertical indicates the concentration of the dissolved metal in mg / l and in the horizontal axis on the day corresponding to the test program designed.

Fig. 3.- Shows a schematic representation in profile of the water treatment facility contaminated with heavy metals object of the invention.

Fig. 4- Shows a plan view of it installation.

Fig. 5.- Shows an enlarged elevation detail of one of the deposits involved in the installation.

Fig. 6.- Shows, finally, a representation schematic in profile of; a substitution sequence of one of the cells of a warehouse.

       \ vskip1.000000 \ baselineskip
    

Examples

The invention will now be illustrated through tests carried out by the inventors, which puts manifest the specificity and effectiveness of the procedure of treatment of water contaminated with heavy metals.

       \ vskip1.000000 \ baselineskip
    

Example 1

A certain type of waste (SMS) was applied to fix heavy metals by filtration taking advantage of capacities of the fungi present in this compost. In 13 table 1 It shows the standard features of SMS used.

       \ vskip1.000000 \ baselineskip
    

       \ vskip1.000000 \ baselineskip
    

       \ vskip1.000000 \ baselineskip
    

(Table goes to page next)

TABLE 1

100

       \ vskip1.000000 \ baselineskip
    

To be able to calibrate the debugging capacity from that residue a set of controlled experiences was developed in the laboratory with different solutions, which are shown in the table 2:

       \ vskip1.000000 \ baselineskip
    

TABLE 2

101

       \ vskip1.000000 \ baselineskip
    

To perform the analysis of the resulting water in each of the test bioreactors, bioreactors such as the shown in detail in Fig. 1, in which the bioreactor is materializes in a tank (2), cylindrical and methacrylate, equipped of a cover (1) through whose central hole the water is introduced contaminated to be treated, a tank equipped with a guide (3) fixed to the cover (1) to attach to a grid of filter material that prevents the buoyancy of the SMS (5) and which is in turn fixed to the base (6), allowing the extraction of the set, so that the SMS is borders between the side wall (2), the grid (4) and the base (6).

Said base (6) has a series of holes (10) through which filtered water passes into the chamber of filtered water (8) determined between the base (11) of the tank and the base (6) between which support stops are established (7).

The treated water is expelled through a tap of exit (9) established in the bottom (11) of the deposit.

In this example of embodiment they were taken 200 ml samples and were stored in sealed plastic bottles which were later analyzed.

These samples were taken each time He renewed the water. In this case, three samples were taken per week. corresponding to each bioreactor.

Different bioreactors were built, to denominating them the solution they contain and the Flow rate to which they are subjected:

-

BL.1: Reference bioreactor, white, subjected to a daily flow of eleven.

-

N1.1: Bioreactor with S1 solution, with a daily flow of 11.

-

N1.100: Bioreactor with S1 solution, They are a daily flow of 100 ml.

-

N2.1: Bioreactor with S2 solution, with a daily flow of 11.

-

N2.100: Bioreactor with S2 solution, They are a daily flow of 100 ml.

-

N3.1: Bioreactor with S3 solution, with a daily flow of 11.

-

N3.100: Bioreactor with S3 solution, They are a daily flow of 100 ml.

       \ vskip1.000000 \ baselineskip
    

In each case the analysis was performed of the metals included in each prepared solution, S1, S2 and S3, is that is, in the case of bioreactors called N1, the lead and chromium, in the so-called N2, iron was analyzed, the nickel, cobalt and manganese, and in the case of bioreactors called N3, iron, zinc, copper and aluminum. In addition, pH values were taken from each of the samples.

To calculate the amount of SMS to be implemented in each of the bioreactors, two important parameters were taken into account. First, consider an adequate amount of compost that would make the treatment effective on the type of water established a priori . And the second, not generating a large amount of waste that could not be handled efficiently by an authorized manager. In the end, 5 kg of SMS was used in each of the bioreactors.

The results obtained are shown in the graphs of Fig. 2, so that the metal concentration studied in (mg / l) of stock solution is referenced with (12), the concentration of metal studied in (mg / l) flow rate of 1 l / day is referenced with (13) and metal concentration studied in (mg / l) flow rate of 100 ml / day is referenced with (14).

It was determined as the first day of the experiment (day 0) the one in which the mother solutions were prepared. Subsequently these solutions remained stored (37 days) without entering the target bioreactors yet. This operation was performed so that possible precipitation phenomena "natural" (due to chemical interferences between metals) did not subsequently generate "false" phenomena of precipitation, attributed to biological processes of sulfate reduction. As can be seen in Fig. 2, these first days without dissolution flow, nor take concentration readings are not included in the graphs.

It was observed in said graphs of Fig. 2 as the average retention rate of dissolved heavy metals exceeds 95% This value is reached in less than 5 days.

In addition, it was observed that in the cases of metals, Fe (III), Ni and Co, both the solutions of the 100 ml / day flow bioreactors such as 1 liter / day, reach very low spill concentration values, with rates of reduction greater than 98%, within a period of less than 15 days, reaching these values practically after 5 days. This rate of purification was maintained during the 73 days of duration of experiment without having exhausted the potential debugger of the SMS.

Something similar was observed for the treatment of waters with metals Pb, Cr and Mn, both the bioreactors of 100 ml / day as in those of 1 l / day, purification rates were reached greater than 90%.

Finally, in bioreactors with the solution S3 (N3.1 and N3.100) metals Fe (II), Zn, Cu and Al obtained reduction values greater than 95%. With the flow of 100 ml / day these values remained in time, In the case of flow of 1 liter / day in which from the tenth day the filter of SMS lost effectiveness for all metals. This circumstance could be due to the existence of preferential paths within of the compost mass in which the capacity has been exceeded SMS sulfate-reducer for a flow of 1 l / day. This phenomenon does not seem to be due to the death of the mycelium of the fungus, because its activity is maintained in the case of the flow of 100 ml / day

       \ vskip1.000000 \ baselineskip
    

Example 2

In view of the results obtained in the example 1, an installation consisting of using cells was designed formed from compost used in mushroom crops, as successive filters, interposed in the water flow to try.

More specifically, see Figs. 3 and 4, the installation that is recommended part of a container or tank origin of contaminated water (15-17), which can be at a higher level than the rest of the installation or not, so that in this second case you will be assisted by a bomb (16) Hydraulics for the generation of water flow through the deposits (20-22), settling at the entrance of the same an entry key (18).

The aforementioned deposits (20), connected in series, contain cells with SMS (19), in which the water flow contaminated generated through them, allows the retention of dissolved heavy metals. So many will be arranged in series deposits (20-22) as needed based on the initial pollutant load of the water to be treated.

In conduction of connection between deposits (20-22) a stopcock is also established (21) as in its output (23).

In Fig. 5 you can see how in the deposit (20) two cells (28) are established through which it passes the water to be purified, the first one in ascending direction and the second one in descending direction, said cells being supported through their lower base (36), of filtering material, on separators (27) and (35), and separated by a central wall (30) that forces to the water to circulate in the sense described above until arriving to the chamber (34) next to which the output of said Deposit.

These cells can be easily manipulated thanks to deposit configuration (20-22), open superiorly, and to the incorporation in the top cover (29) of the aforementioned hitch media cells (31), which may be easily substituted, as can be seen in the sequence of figure 6. Said top rigid cover (29) will be of material filter, avoiding the SMS output from the cell. The bumpers (32) present in the lateral and central walls (30) of the tanks (20-22) avoid the buoyancy of the cells.

Also noteworthy is the fact that between the bases (36) of the cells (28) and the separators (27-35), respective boards of tightness (33) that prevents contaminated water, that there is no crossed the SMS present in the cells, can not access the collection tanks for purified water (25-26).

In the event that there is no difference between the tank (22) and the collection tank for treated water (25) is establish a hydraulic pump (24) for water conduction refined inwards.

The system allows, in case of interest, the recirculation or the unique flow of natural or forced character.

Given the modular design of the system, it can function even when one of the cells is not installed or is being replaced It also eliminates the need for recirculation of the fluid with the consequent cost of pumping.

The retention capacity is designed by adding more cells in series in the direction of flow, so that you can play with the system based on the pollutant load of origin.

Claims (11)

1. System for the treatment of water contaminated with heavy metals, comprising at least one purification tank (20; 22) provided with at least one cell (28) containing compost with fungus mycelium (19), characterized by the fact that said debug tank is open superiorly. 2. System according to claim 1, characterized in that the purification tank (20; 22) comprises a water inlet in its lower zone and a filtered water outlet in the lower and opposite zone of the purification tank. 3. System according to claim 2, characterized in that the depuration tank (20; 22) comprises an intermediate wall (30) defining two cells separated by said intermediate wall, which is smaller than the storage tank. depuration. 4. System according to any of the preceding claims, characterized in that it comprises means for retaining (32) the contents of the cell (28) within the purification tank (20; 22). System according to claim 4, characterized in that the cell (28) comprises an upper cover (29), and the retention means (32) are stops arranged in the walls of the purification tank (20; 22 ) against those that said cell cover bumps to avoid its buoyancy in the purification tank. System according to claim 5, characterized in that the upper cover (29) of the cell (28) is rigid and of a filtering material, to prevent the compost (19) from leaving the cell. 7. System according to claim 5 or 6, characterized in that the upper cover (29) of the cell (28) comprises hooking means (31) that allow the extraction of the cell through the open upper part of the tank purification (20; 22). System according to any of the preceding claims, characterized in that the cell (28) comprises a lower base (36) of filtering material that is fixed to separators (27, 35) arranged in the walls of the purification tank (20; 22). 9. System according to claim 8, characterized in that the purification tank (20; 22) comprises a filtered water chamber (34) arranged under the lower base (36) of the cell (28). 10. System according to any of the preceding claims, characterized in that the compost with fungus mycelium (19) is the only purifying element present in the system. 11. System according to any of the preceding claims, characterized in that the compost with mycelium fungus (19) is the residue directly obtained from the cultivation of mushrooms or other fungi, without receiving any type of treatment.