RU2802194C2 - Method for purifying water from excess of phosphates in aquarium of oceanarium for keeping marine hydrobionts - Google Patents

Abstract

FIELD: water processing.

SUBSTANCE: invention is related to water purification and regeneration in systems with a closed water supply cycle with maintenance of hydrobionts and can be used in artificial cultivation of various living objects that require high quality circulating water. To reduce the concentration of phosphates, a contact chamber is used to ensure the binding and precipitation of phosphates by lanthanum chloride. The amount of lanthanum chloride supplied to the contact chamber is calculated by the formula: C=A×N×2.54, where C is the amount of lanthanum chloride supplied per unit of time in terms of anhydrous, g, A is the amount of phosphates in the incoming water, g/L, N is the number of liters of water entering the contact chamber per unit of time, 2.54 is the coefficient. The supply of purified water to the contact chamber is carried out continuously and is calculated by the formula: X=V×A/100×24, where X is the rate of supply of purified water to the installation L/h, V is the volume of the system, A is the percentage of purified water per day. A solution of lanthanum chloride is supplied with a dosing pump at intervals of 2 to 10 times per hour to the inlet of the circulation pump of the contact chamber, which has a volume of 0.05% to 1% of the volume of the aquarium, while the contact chamber is installed above and next to the mechanical filtration tank, in which the bound insoluble precipitate settles on a mechanical filter. Then the purified water passes through the load to the drain pipe, enters the filter from a finely porous sponge for additional purification and is fed into the aquarium collector.

EFFECT: invention makes it possible to reduce the consumption of clean water and increase the stocking density of aquatic organisms.

1 cl, 2 tbl, 2 dwg

Description

Solving the problems of protecting the health of aquatic organisms, marine and freshwater artificial and natural ecosystems is now becoming increasingly important, as is the improvement of modern technologies in general and sanitary hydrobiology, aquaristics and oceanology (Pronina G.I., 2008; Glyzina O.Yu. and et al., 2011; Loger T., 2012; Zhigin A.V., Dementiev D.V., 2016; Sadykova G.G., 2018; Ruzhitskaya O.A., Mendesa S., 2019; Afanas'eva A.A. , 2021; Gubernat S. et al., 2020; Nakarmi A. et al., 2022; Shyam S. et al., 2022).

Eutrophication (eutrophication, hypertrophication) in sea tanks and aquariums has led to the widespread development of the industrial creation of special methods, substances and apparatus for "eutrophication management") and, in particular, the use of lanthanum chloride (lanthanum chloride) "phosphoras management lanthanum" (Pitruk D. L., 2012; Kaplya M.V., Snyadovsky Yu.A., 2016; Pronina G., Koryagina N., 2017; Klochkov D.G., Abrosimova N.A., Kokhanov Yu.B., 2020; Holmes -Farley R., 2005; Shraddha K., Dipika J., Arti M., 2018; Bouzas A. et al., 2019; AdinN., Nuha H.H., 2020: Gao G. et al., 2020; Zhao D. et al., 2021; Elkhlifi Z. et al., 2022; Zhang M. et al., 2022).

In oceanariums, methods for removing excess phosphates and other eutrophicants, using developments in domestic and international hydroecology, can reduce pollution and improve the composition of the water used with a fairly high accuracy (Zhitenev B.N., Novoseltseva A.G., 2013; Kotov A.E. ., 2015; Zhugdurova S.V., Baldanova A.N., Tarnuev D.V., 2020; Sedlak R., 2018; Royer S.J. et al., 2021; Kawase M., Miura K.; Wu D. et al., 2022; Yin Y. et al., 2022).

While certain technologies and apparatuses can achieve very low phosphorus concentrations, each has its own limitations. This may be a high dependence on physico-chemical conditions, the need for membranes that can potentially lead to pollution problems, the formation of chemical deposits that may be irreplaceable, the need for large areas, etc. Therefore, there is a need for methods that can consistently reduce phosphate to low levels, rely less on ideal operating conditions, have high throughput without contamination problems, small footprint, and minimal waste generation. As a rule, inorganic phosphorus is removed from a conventional hobby aquarium using a skimmer. However, the effectiveness of skimmers in removing inorganic orthophosphorus ions is insufficient. Therefore, special reactors with lanthanum chloride are one of the most popular, promising and effective tools for the correction of phosphates in marine aquatic ecosystems, especially for professional use. As a rare earth metal, lanthanum has a significant cost, so it is also the most practical in the largest volumes of aquariums (Makshanova K.A., 2015; Lebedeva A.P., Nikiforov A.I., 2020; Carlson V.A. et al. , 2008; Zhang Y., Wong K.S., 2017; Jia Z. et al., 2020; Gubernat S. et al., 2020; Liu M. et al., 2021).

In sea water, organic phosphorus is represented by a much greater variety of forms than inorganic phosphorus. At pH8.1, sea water contains H ₂ RO ₄ , 79% HRO ₄₂ and 20% RO ₄₃ . At higher pH values, the equilibrium shifts in favor of PO ₄₃ and HPO ₄₂ becomes smaller. Under natural conditions, orthophosphate is readily taken up by algae, so lowering phosphate levels limits excess algae growth in the aquarium. Although some species of microalgae grow better at lower levels of phosphate, they can also significantly regulate their own consumption of inorganic phosphate, depending on the level of concentration of the latter. Many aquatic organisms can also break down organic phosphate to inorganic orthophosphate with the help of enzymes, and then consume it later. Thus, to limit the growth of unwanted algae, it is necessary to maintain the concentration of both types of phosphate at low values, including reactors with lanthanum chloride (Gribovskoy N.N., Selivanov S.N., Sharipov M.P., 2009; Zhigin A.V. ., 2016; Vasiliev A.A., Poddubnaya I.V., 2016; Zhang Y. et al., 2021; Koh KY, Zhang S., Chen JP, 2021).

For the needs of the aquarium, only the method of removing phosphates from water using lanthanum chloride is considered, because:

- the use of aerotanks with activated sludge requires a larger area to accommodate the sump. In all aquariums, equipment is selected and installed in such a way as to use a minimum of space. All architectural solutions are aimed at increasing the demonstration spaces.

- when using adsorbents based on iron and aluminum, the adsorbent capacity is much lower than that of lanthanum, which implies a large reactor capacity and large volumes of substrate to be replaced, which occupies a usable area. The cost of this method is also high due to the need to replace large volumes of aluminum and iron compounds at a high concentration of phosphate in water.

The prototype of the method are the methods described in the article Zhang Y., Wong KS "Lanthanum chloride or lanthanum carboxylate for orthophosphate removal in seawater aquarium-a feasibility study". (https://web.archive.org/web/20170830102611/http://www.beananimal.com/media/10090/zhangwongorthophosphateremovalpaper_1_pdf) describing a study designed to evaluate the removal efficiency of PO ₄₃ (high levels of orthophosphate, from 2 up to 5 mg/l) with LaCl ₃ , "Starver" from LoChlor in Ocean Park Hong Kong marine aquariums and pools. In situ addition of 5.49 mg/m ³ lanthanum to the screens before the sand filters in a 51 m ³ pool reduced the PO ₄₃ concentration to 3.0 mg/m ³ from 4.3 mg/m 3 immediately after dosing. Both results showed that the efficiency of La for removing phosphates also depends on the efficiency of the filtration itself. The lanthanum compound could pass through the filters into the pool depending on the increase in turbidity after treatment. Therefore, the introduction of the lanthanum compound into the aquarium must be done very carefully, and it is best done in a side loop equipped with high efficiency filters to avoid any potential harmful effects on aquatic organisms due to leakage of the lanthanum compound into the pool.

The disadvantages of this solution, designed for large volumes, is mechanical cleaning, which is less effective and therefore residual lanthanum is detected in the water, coming from the filter back to the pool or aquarium system.

A similar technology is known that almost also purifies water "Accelerate phosphate removal with the new lanthanum reactor from Acrylique Fm" (publication of recommendations on the website https://web.archive.org/web/20201112030933/https://reefbuilders.com/ 2017/03/14/lanthanmn-chloride-reactor-from-acrylique-fm/) where lanthanum chloride is also used as one of the effective ways to remove phosphates from reef aquarium water. Many liquid PO4 removers are available to aquarists under various brand names, but the way they are added to reef tanks is ineffective for complete phosphate removal and only works best at moderately high levels of phosphate. However, in this new design from Acrylique FM of France, it can be seen that there is a venturi valve for supplying lanthanum chloride. The slow flow of water through the reactor through the filter medium helps to slow down the flow of the solution so that lanthanum phosphate precipitates can form and enter the filter media.

The disadvantages of this method are the increased consumption of components, tk. in it, filtration is carried out through a synthetic winterizer, which needs to be changed often. The proposed method is more efficient, since the primary sediment is removed by settling and draining from the tank. It is also more economical, since draining the sediment before it enters the mechanical filter reduces the consumption and frequency of washing the mechanical filter load. The concentration of lanthanum chloride in this solution is low, designed to remove low amounts of phosphate in aquariums less than 5 tons. And in this configuration, the method and the dephosphorator (DF) take up a lot of space, which is scarce in urban conditions, and the synthetic winterizer will not retain all the sediment of lanthanum phosphates, which enters the dephosphorator and reacts.

There is a similar patent RU64019U1 "LIFE SUPPORT SYSTEM OF THE MAIN TANK OF THE OCEANARIUM" (Patent holders: "Davydov Vladimir Nikolaevich, Selivanov Nikolai Pavlovich"), which includes life support systems of the main tank of the oceanarium, intended mainly for marine hydrobionts, characterized by the fact that they contain equipped with pumping equipment and water treatment systems connected to the main tank, sea water preparation, as well as connected to the main tank, mainly through a distributing manifold and / or through a balance chamber with the possibility of recirculation and water admixture, containing at least one main filter, a combined system of mechanical and biological water purification, containing at least a water ozonation apparatus - a contact tower and a degassing chamber, a water sterilization system containing at least one protein skimmer, a protein purification system, as well as sewage systems, measuring and regulating the pH and redox potential of water, which are switched with the possibility of regulating at least fractional water sterilization by ozonation depending on the required correction of the redox potential of the water in the tank, and at least most of the mentioned purification systems are connected to the main tank, mainly with the possibility of separating the recirculating water flows with the formation of non less than three loop-shaped branches with different throughput, including a branch containing at least one of the aforementioned main filter of combined mechanical and biological water purification and supplementing it with a flotation branch containing at least one of the above-mentioned protein skimmer and a branch of water sterilization containing at least one water ozonation apparatus, moreover, the main of the mentioned - the most loaded branch, including at least one of the above-mentioned main filter, is designed to pass more than half of the total recirculation flow in the mechanical and biological treatment mode. The life support system of this main tank of the aquarium is equipped with at least two main filters with a filter body, preferably including sequential or alternating layers of gravel and sand, at least partially populated, preferably, nitrifying bacteria. It is also equipped with at least one backwash tank and a system for backwashing the filtering body of each of these filters, which communicates with each of the main filters; predominantly sand filters. It is equipped with dispensers of purified recirculating water and mixed water distributed, mainly along the perimeter of its bottom part, as well as at least one located in the central zone of the bottom part. The life support system of the main tank of the oceanarium according to claim 1, characterized in that the main tank is equipped with at least one sand trap connected to the backwash tank and / or sewage system, while the sand trap is located mainly on the outside of the tank and is equipped with at least two vacuum pumps introduced into the tank, at least one flexible pipeline equipped with at least one vacuum sander head. Also, the sea water preparation system is equipped with a device, for example, a baffle or an equipped place for storing a replenished supply of sea salt, and the tank is filled with sea water prepared from the said sea salt, or filled with natural sea water or a mixture prepared from natural sea salt, to ensure normal operation during operation. sea water and chemically optimal impurities for hydrobionts living in the tank.

The disadvantage of this utility model is the lack of a specific description of the node itself and the method of using this dephosphation system.

Also close is the analogue described in the brochure Haghseresht F. (A revolution in phosphorous removal // Phoslock Water Solutions Ltd. In. - 2005. - P. 21), which describes a bentonite modified with lanthanum, known as Phoslock, which reduces the amount of orthophosphates, forming insoluble precipitate. Since the rare earth element is in the clay structure, it can react with the phosphate anion in the water body or remain in the clay structure under a wide range of physicochemical conditions. Granulated Phoslock is mixed with water on site using specially designed applicators. As a result of mixing, the granulated Phoslock is then dispersed into fine particles that can be removed.

The disadvantage of this method is a labor-intensive technique, as well as the lack of data on the technology of use in closed systems with a very high level of phosphate intake - for keeping fish and aquatic organisms with the highest stocking density. Also in the analog there is a high consumption of the substance, because. lanthanum is used in a mixture with clay, which significantly increases the cost of the mixture itself and increases its consumption.

The existing analogue from the study of Koh K.Y., Zhang S., Chen J.P. (Incorporation of lanthanum particles to polyethersulfone ultrafiltration membrane for specific phosphorus uptake: Method comparison and performance assessment // Journal of Colloid and Interface Science. - 2021. - T. 601. - C. 242-253) also uses lanthanum-containing components in the form of a membrane from polyethersulfone and sulfonated polyphenylene sulfone for phosphorus removal. This membrane showed high adsorption capacity (48.0 mg/g), fast kinetics (equilibrium after 6 hours) and high water permeability. A study of several filtration cycles showed that the membrane was successfully reused to treat water with a low phosphate content, meeting the 0.15 mg/L phosphate limit. Phosphate removal by membranes occurs by ion exchange and electrostatic attraction or complexation, removing phosphates in a process of periodic adsorption or membrane filtration.

The disadvantages of this method is the increased complexity - not only lanthanum is used, but also a special membrane and there is no possibility of its reuse due to leakage of lanthanum.

Close analogue from the technique described in TKERacer619's article "Masterflex Lanthanum Chloride Reactor" (website at https://web.archive.org/web/20211229172509/http://www.reefcentral.com/forums/showthread.php ?t=2667999), which describes the continuous mixing of LaCl with water from a tank using a system capable of creating significant pressure to avoid clogging the filter. This is achieved with a Masterflex continuous peristaltic pump with two heads. One head uses a large tube to push waste water through the reactor, while the second head uses a small tube to inject a dilute lantine chloride mixture. The introduction of LaCl into the wastewater stream results in the precipitation of phosphates from the wastewater. This precipitate is fed into the bottom of the mixing chamber filled with bioballs to obtain complete mixing and reaction of LaCl before it reaches the filtration stage. Part of the sediment will settle to the bottom of the mixing chamber. The rest of the sediment moves into the side 20 Big Blue filter housing, which contains a 5 micron pleated sediment filter. Most of the solid particles will settle to the bottom of this chamber, but fine particles will be filtered out by the filter. Eventually, this filter will become clogged and will need to be cleaned by soaking in vinegar, after soaking for 24 hours and rinsing, the filter will be as good as new. It can be used many times. Thanks to the pressure generated by the Masterflex peristalsis, this filter can last up to 3 months without cleaning. The tubing used provides a continuous pressure of 10 psi, so a 10 psi pressure switch is used in front of the filter. This will shut down the pump if the filter becomes clogged until regular maintenance is performed. Without a pressure switch, there is a risk of bursting the pipe, resulting in a spill if the filter becomes clogged. In a calcium reactor, it is common to let wastewater flow through the reactor, but in this situation, we need to push through because of the 2nd LaCl pressure pump. If there was a blockage, and wastewater was drawn through the 2nd head, they would return back to the sump. The final step is to feed the wastewater through a 1 micron filter sock as a precautionary measure.

The disadvantages of this method are the lack of data on the technology of using dephosphation in closed systems with a very high level of phosphate intake - for keeping hydrobionts with the highest possible stocking density, and there is also no assessment of the efficiency of the mechanical filter and data on the efficiency of the system.

A similar application has a technique from the article Ruzhitskaya O., Gogina E. (Methods for removing of phosphates from wastewater // MATEC Web of Conferences. - EDP Sciences, 2017. - T. 106. - C. 07006), which shows the technology for removing phosphates from wastewater, which is about 60-70% at a concentration of phosphates of about 14 mg/l in the incoming wastewater. The phosphate removal efficiency initially increased to 99%, but decreased to about 60% after 15 days. Interacting with phosphates in this method, ferric ions form basic iron phosphate and iron orthophosphate octahydrate. At the same time, a reaction occurs to form iron hydroxide, which adsorbs phosphates and other solid particles of various origins; in addition, it acts as an adsorbent for other phosphorus-containing compounds. In turn, the activated sludge, which remains in suspension, adsorbs hard-to-set iron hydroxide particles and thus makes the sludge flakes heavier and larger. Subsequently, a biological film forms on the feed material, and a film of iron oxide and iron phosphate forms on the surface, so the concentration of dissolved iron drops to almost zero.

The disadvantages of this method are the use of aluminum and iron, which have a much lower adsorption capacity than lanthanum chloride, and therefore require a larger area for the reactor and a larger amount of filler, which, in the presence of high concentrations of phosphate in water, makes this method much more complicated and more expensive than the use of lanthanum chloride.

The invention relates to aquarium technology, in particular to methods for ensuring the vital activity of marine hydrobionts and can be used to create conditions for the life support of animals and plants living in a salty aquatic environment. The addition of LaCl ₃ to aquarium water causes phosphate to precipitate out of solution, but to increase the efficiency of the reaction, it is best to concentrate LaCl ₃ in a smaller volume, for example, in the proposed reactor design.

In any marine artificial ecosystems, many biochemical components contain phosphorus - in almost every cell of aquatic organisms, this element is present in a wide variety of complexes. Molecules of DNA, ATP, phospholipids (lecithin), many proteins contain phosphorus groups. That is why it is necessary to develop an effective method for removing excess of this metabolic product and chemical element from various aquariums.

The invention works as follows.

The method for purifying water from excess phosphates in an aquarium containing marine hydrobionts operates on the chemical mechanism of binding and precipitation of PO ₄ molecules with lanthanum chloride (LaCl ₃ ). One LaCl ₃ molecule binds three PO ₄ molecules and, based on this ratio, the required amount of LaCl ₃ is calculated to neutralize the excess amount of PO ₄ .

This calculation is performed correctly and without errors, because an excess amount of LaCl ₃ can affect the stability of the hydrochemical parameters of water in the system, the life and health of its inhabitants, which is also achieved by guaranteeing that LaCl ₃ does not enter the aquarium directly.

The calculations in the method require control of the dynamics of the increase and decrease of PO ₄ in the aquarium system. And, in the case of an increase in the level of phosphate concentration, a multi-stage cleaning is launched in the dephosphorator.

In the proposed method, to reduce the concentration of phosphates, a contact chamber is used that provides binding and precipitation of phosphates by lanthanum chloride, while the amount of lanthanum chloride supplied to the contact chamber is calculated by the formula:

C=A×N×2.54

Where C is the amount of lanthanum chloride supplied per unit of time in terms of anhydrous, g,

A - the amount of phosphates in the incoming water, g / l,

N is the number of liters of water entering the contact chamber per unit of time,

2.54 - coefficient

The supply of purified water to the contact chamber is carried out continuously and is calculated by the formula:

X=V×A/100×24

Where: X - the rate of supply of treated water to the installation l / h.

V is the volume of the system.

A is the percentage of purified water per day.

Next, the lanthanum chloride solution is fed with a dosing pump at intervals of 2 to 10 times per hour to the inlet of the circulation pump of the contact chamber, which has a volume of 0.05% to 1% of the volume of the aquarium.

In this case, the contact chamber is installed above and next to the mechanical filtration tank, in which the bound insoluble precipitate settles on the mechanical filter.

Then the purified water passes through the load to the drain pipe, then it enters the filter from a finely porous sponge for additional purification, after which the purified water is supplied to the aquarium collector to ensure the vital activity and maintain the health of marine hydrobionts.

The invention is illustrated by drawings in Fig. 1 showing:

1. Taps for adjusting the water supply from the aquarium

2. Contact chamber solution 50 l

3. Water mixing pipe with lanthanum chloride solution

4. Circulation pump

5. Mixing compartment

6. Mesh sump

7. Perforated plate with fine sponge filter

8. Water supply pipe to the mechanical filter

9. Flow filter

10. Mechanical filter capacity with sump 500 l

11. Water supply pipe to the aftertreatment tank

12. Drain plug

13. Sump taps

14. Finely porous sponge filter

15. Water supply from the aquarium

16. Supply of lanthanum chloride solution

17. Sludge drain

The general scheme of the method is shown in Fig. 2, where are indicated:

1. Circulation pumps

2. UV sterilizers

3. Pressure sand filters

4. Denitrifier

5. Protein skimmer

6. Dephosphor

7. Degassing chamber

8. Aquarium

9. Biofilter

10. Collector

As an example of the possibility of implementing the stated purpose and achieving the specified technical result, we present the following data.

Water enters one opening of the reactor and exits the other, reacting with a large perforated plate to homogenize the flow of water through it. The contact chamber has a conical shape. At the bottom of the tank there is a valve for draining the sediment. The contact chamber is installed on the frame above and next to the mechanical filtration tank.

Mechanical filtration is carried out in a contact chamber with a sediment drain valve installed at the bottom of this tank. The flow filter itself is a container without a bottom, divided horizontally into cells by perforated partitions filled with bioload for recirculating water supply installations.

After contact of the treated water with a solution of lanthanum chloride in the contact chamber, the mixture from the first contact chamber passes into the second chamber and is fed to the mechanical filter. In the second chamber, an insoluble precipitate of lanthanum phosphate formed during the chemical reaction LnCl ₃ ×nH ₂ O+PO4 ₃ =LnPO ₄ +C1 settles on a mechanical filter.

A solution of lanthanum chloride is fed to the inlet of the circulation pump of the contact chamber. The dimensions of the contact chamber of the installation make it possible to ensure the reaction between all the phosphate entering the system and the lanthanum solution, as well as to carry out the precipitation of the entire amount of the resulting precipitate of lanthanum phosphate. Delivery is carried out using a dosing pump.

The action of this method for water purification is achieved by contact and chemical reaction of a solution of lanthanum chloride with the water of the aquarium system. In the work of the DF, water is used, which is prepared by dissolving specialized aquarium salt in water that has been purified through a reverse osmosis unit. Salt has such a composition that after dissolution, the resulting water is as close as possible in its characteristics to the ocean water of the habitat of the exhibited species of hydrobionts. Obtained characteristics (Ph - 8.1-8.3, dKHO 7-9, calcium - 380-420 mg/l, magnesium - 1150 - 1250 mg/l, nitrates, phosphates, silicates - 0 mg/l and potassium - 380 -400 mg/l) allow it to be included in the life cycle of an aquarium at any stage.

The technical result of the developed invention is the stabilization of the hydrochemical parameters of the aquatic habitat of marine hydrobionts, increasing the efficiency of their life support, creating conditions as close as possible to natural conditions for each group of hydrobionts, compatible in terms of habitat and lifestyle, which makes it possible to provide the best conditions for long-term maintenance in marine tanks, as well as the economical use of water resources by reducing operating energy costs, which is achieved by using a recirculation scheme for water purification and renewal in the separation and combination method by adding a certain percentage of sea water.

Thus, the proposed invention for water purification and regeneration in systems with a closed water supply cycle with the content of aquatic organisms makes it possible to reduce the consumption of clean water per circulating water by up to 75%, and it is possible to clean sea tanks up to 1,200,000 liters in this way. The method allows to increase the productivity of the closed system in the stocking density of fish from 80% to 120%.

Claims (1)

A method for purifying water from excess phosphates in an aquarium containing marine hydrobionts, characterized in that to reduce the concentration of phosphates, a contact chamber is used to ensure the binding and precipitation of phosphates by lanthanum chloride, while the amount of lanthanum chloride supplied to the contact chamber is calculated by the formula C=A×N ×2.54, where C is the amount of lanthanum chloride supplied per unit of time in terms of anhydrous, g, A is the amount of phosphates in the incoming water, g/l, N is the number of liters of water entering the contact chamber per unit of time, 2 ,54 - coefficient, the supply of purified water to the contact chamber is carried out continuously and is calculated by the formula X = V × A / 100 × 24, where X is the rate of supply of purified water to the installation l / h, V is the volume of the system, A is the percentage of purified water per day; a solution of lanthanum chloride using a dosing pump is fed at intervals of 2 to 10 times per hour to the inlet of the circulation pump of the contact chamber, having a volume of 0.05% to 1% of the volume of the aquarium, while the contact chamber is installed above and next to the mechanical filtration tank , in which the associated insoluble sediment settles on a mechanical filter, then the purified water passes through the load to the drain pipe, then it enters the filter from a finely porous sponge for further purification, after which the purified water is supplied to the aquarium manifold.

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