KR20210069366A - Method for preparing sewage treatment material used for removing po4-p and nh3-n, sewage treatment material prepared thereby, and sewage treatment system comprising the same - Google Patents

Abstract

The present invention relates to a method for preparing a sewage treatment material for PO4-P and NH3-N removal, a sewage treatment material prepared thereby, and a sewage treatment system including the same. The method includes the steps of: (A) grinding an oyster shell; and (B) calcining the oyster shell and then attaching microalgae to the oyster shell to prepare a sewage treatment material. According to the present invention, the sewage treatment material is prepared using oyster shells, it is possible to recycle oyster shells that have caused problems such as odor and coastal ecosystem pollution, and thus environmental pollution can be reduced. In addition, it is possible to produce a sewage treatment material of excellent performance capable of simultaneously treating phosphorus (PO4-P) and nitrogen (NH3-N) in sewage at a high removal rate.

Description

A method for manufacturing a sewage treatment material for removing PO4-P and NH3-N, a sewage treatment material manufactured thereby, and a sewage treatment system comprising the same MATERIAL PREPARED THEREBY, AND SEWAGE TREATMENT SYSTEM COMPRISING THE SAME}

The present invention relates to a method for manufacturing a sewage treatment material for removing contaminants contained in sewage, a sewage treatment material manufactured thereby, and a sewage treatment system including the sewage treatment material.

Recently, as the standards for nutrient discharge from sewage treatment plants have been strengthened, research to reduce the concentration of nutrients in sewage is being conducted. In fact, various sewage treatment methods are being applied, and in particular, the standard activated sludge method capable of treating phosphorus and nitrogen is widely applied at home and abroad. Compared to other methods, the standard activated sludge method does not use chemicals, so the maintenance cost is low, and research and development on various transformation processes are in progress. However, depending on the type of filler used in the aeration tank, there is a disadvantage in that it consumes a lot of money, and since the treatment efficiency of TN is 20 to 30% and that of TP is only 10 to 25%, additional Therefore, advanced treatment facilities are required. As fillers for the aeration tank, natural materials such as elvan stone and zeolite, processing materials such as ceramics, porous polyurethane, industrial byproducts of magnetite powder, and waste tires have been proposed. Such fillers exhibit relatively low cost and high efficiency compared to conventional materials, but may act as a cause of secondary environmental pollution such as heavy metal contamination due to the material properties of the filler.

On the other hand, as of 2016, oysters are being farmed around the world with a production scale of about 43.8 billion tons. About 70% of the total weight of oysters is composed of shells, and about 96% of oyster shells are in the form of calcium carbonate, so it is also used as a cement coagulant and calcium supplement. However, only 30% of the generated oyster shells are recycled, and most of the rest are landfilled or stored illegally, causing secondary environmental pollution such as odors, pests, and water pollution due to leachate. Therefore, it is urgent to find a recycling method.

Korea Patent Publication No. 10-1998-076547 (published on: November 16, 1998) Korean Patent Application Laid-Open No. 10-2002-0043024 (published on June 8, 2002)

The technical problem to be solved by the present invention is a novel sewage treatment that can simultaneously remove _{phosphorus phosphate (PO 4} -P) and ammonia nitrogen (NH _{3 -N) in sewage using oyster shells as a method for recycling oyster shells} An object of the present invention is to provide a method for manufacturing ashes, a sewage treatment material manufactured thereby, and a sewage treatment system including the sewage treatment material.

In order to achieve the above technical object, the present invention comprises the steps of (A) grinding oyster shells; And (B) after calcining the oyster shell, attaching microalgae to the oyster shell to prepare a sewage treatment material, PO ₄ -P and NH ₃ -N suggesting a method of manufacturing a sewage treatment material for removal.

In the step (B) is a microalgae microalgae capable of removing the NH ₃ -N, e.g., Chlorella vulgaris (Chlorella vulgaris), are used to Spira platen sheath (Arthrospira platensis), des mousse as not keystore Gracilis ( Ankistrodesmus gracilis ), Senedesmus accuminatus ( Scenedesmus accuminatus ) and Senedesmus quadricauda ( Scenedesmus quadricauda ) At least one selected from the group may be used, but it is not necessarily limited to the microalgae. .

In addition, the method of attaching microalgae to the calcined oyster shells in step (B) is not particularly limited. For example, when microalgae are inoculated with the calcined oyster shells in a water tank filled with water, the microalgae adhere to the surface of the oyster shells. After a certain period of time, it acts as a substrate to obtain oyster shells with microalgae attached to the surface.

On the other hand, the _{sewage treatment material for removing PO 4} -P and NH ₃ -N according to the present invention may be manufactured using only oyster shells fired at one specific temperature or temperature range, as well as at two or more different specific temperatures or temperature ranges. It can also be prepared by attaching algae to each calcined oyster shell and then mixing them.

For example, a method of preparing a sewage treatment material by attaching microalgae to oyster shells calcined at different temperatures and mixing them, comprising the steps of: (a) grinding oyster shells; (b) calcining the oyster shells at 100° C. and attaching microalgae to the oyster shells to prepare a first sewage treatment material; (c) calcining the oyster shells at 600 to 800° C. and then attaching microalgae to the oyster shells to prepare a second sewage treatment material; and (d) mixing the first sewage treatment material and the second sewage treatment material (see FIG. 1 ).

At this time, it is preferable to mix the first sewage treatment material and the second sewage treatment material in the step (d) in a weight ratio of more than 0: 10 and less than 10: 0, more preferably, the first sewage treatment material and the second sewage treatment material The treatment material may be mixed in a weight ratio of 3: 7 to 5: 5.

And, the present invention proposes a sewage treatment material for removing _{PO 4} -P and NH ₃ -N obtained by the manufacturing method in another aspect of the present invention.

Furthermore, in another aspect of the present invention, the present invention proposes a sewage treatment system having an aeration tank or a sample filling layer filled with the sewage treatment material for removing _{the PO 4} -P and NH _{3 -N.}

As an example of the sewage treatment system, when describing a sewage treatment system to which the standard activated sludge process, which is currently most widely applied to sewage treatment, is applied, a pretreatment unit for removing coarse particles such as sand contained in the sewage; a primary treatment process unit for sedimenting and/or removing suspended solids in sewage using natural sedimentation; a secondary treatment unit for processing the upper layer water that has passed through the primary treatment unit into the aeration tank; a disinfection unit that disinfects the effluent that has passed through the secondary treatment process unit before discharging; and a sludge treatment unit for dewatering and finally disposing of sludge generated according to the processes in the primary treatment unit and the secondary treatment unit, and the aeration tank included in the secondary treatment unit is provided according to the present invention. A sewage treatment system is formed by filling the sewage treatment material for removing _{PO 4} -P and NH _{3 -N.}

Environmental pollution by recycling oyster shells that have caused problems such as odor and coastal ecosystem pollution in the past by manufacturing sewage treatment materials using oyster shells through the method of manufacturing a sewage treatment material for removing _{PO 4} -P and NH ₃ -N according to the present invention At the same time, it is possible to produce a sewage treatment material with excellent performance that can simultaneously treat _{phosphorus (PO 4} -P) and nitrogen (NH _{3 -N) in sewage at a high removal rate.}

1 is a process flow diagram showing each step of the method of manufacturing a sewage treatment material for removing _{PO 4} -P and NH ₃ -N according to the present invention.
2 is an XRD analysis result of calcined oyster shells in Examples of the present application.
3 is a schematic diagram of an upflow permeable outflow device used to evaluate the pollutant removal performance of the sewage treatment material in the present embodiment.
_{Figure 4 is a change in the concentration of PO 4} -P of artificial sewage in the inflow (Con) and outflow (POS) of the upflow permeable outflow device (FIG. 4 (a)) and the filling weight of POS100, POS600, POS800 (g) According to PO ₄ -P removal amount (mg) (Fig. 4 (b)) is a measurement result.
5 is a result of measuring the NH ₃ -N removal performance of microalgae ( Chlorella vulgaris ) in the present Example.

In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

Since the embodiment according to the concept of the present invention may have various changes and may have various forms, specific embodiments will be illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiment according to the concept of the present invention with respect to a specific disclosed form, and should be understood to include all changes, equivalents or substitutes included in the spirit and scope of the present invention.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that the described feature, number, step, operation, component, part, or combination thereof exists, and includes one or more other features or numbers. , it is to be understood that it does not preclude the possibility of the presence or addition of steps, operations, components, parts, or combinations thereof.

Hereinafter, the present invention will be described in more detail by way of examples.

Embodiments according to the present specification may be modified in various other forms, and the scope of the present specification is not to be construed as being limited to the embodiments described below. The embodiments of the present specification are provided to more completely explain the present specification to those of ordinary skill in the art.

<Example>

The present embodiment, oyster shell Chlorella vulgaris (Chlorella vulgaris) at a firing were attached Chlorella vulgaris (Chlorella vulgaris) after crushed oyster shell calcination at 100 ℃ a first wastewater treatment material in the production, and after grinding 600 ℃ or 800 ℃ After attaching to prepare a second sewage treatment material, the first sewage treatment material and the second sewage treatment material are mixed in a weight ratio of 3: 7 or 5: 5 to remove _{PO 4} -P and NH _{3 -N according to the present invention} To prepare a sewage treatment material for use as a filler in a sewage treatment facility, an indoor experiment simulating a sewage treatment system was performed, and the removal performance of _{PO 4} -P and NH _{3 -N was evaluated.}

The oyster shells used in this example were collected from Parksinjang, Geoje-si, located on the southern coast of Gyeongsangnam-do. The collected oyster shells were cleaned and foreign substances were removed and calcined for 6 hours at different temperatures of 100°C (POS100), 600°C (POS600), and 800°C (POS800) for the experiment. The calcined oyster shells were pulverized and sieved to a particle size of 0.5 mm to 10 mm (Fig. 1).

The calcined oyster shells were analyzed for chemical composition using X-Ray Fluorescence Spectrometer (SHIMADZU, XRF-1800, Japan) equipment. The chemical composition of calcined oyster shells is shown in Table 1 below.

<Table 1> Result of component analysis of pyrolysis oyster shell

The Ca content of POS100 was about 96.25%, and POS600 and POS800 were about 99.64% and 99.63%. POS100 detects 11 types (Ca, Na, Mg, Cl, S, Si, Sr, FE, Al, P, K), whereas POS600 and POS800 detects only 3 types (Ca, S, P) became

As the calcination temperature increases, _{inorganic compound components such as calcium carbonate (CaCO 3} ) are decomposed into carbonate, resulting in a higher Ca content ratio, and trace elements are judged to be less than the detection limit. In addition, crystallinity analysis of calcined oyster shells was performed using X-Ray Diffractometer (XRD, Philips, X'Pert-MPD System, Netherlands) equipment.

2 shows the results of XRD analysis of calcined oyster shells. Calcium carbonate (CaCO ₃ ) was confirmed to be the main component, and the difference in intensity was seen according to the firing temperature (Hellen et al., 2019). Intensity of CaCO ₃ appeared in the order of POS600, POS800, and POS100. In addition, the response of CaMg(CO ₃ ) ₂ Intensity was also shown in POS100, POS600, and POS800. CaMg(CO ₃ ) _{2 As} a kind of carbonate mineral, it is known that it is difficult to synthesize inorganically at a low temperature, and its crystallinity is stabilized at about 700° C. (Bertram et al., 1991; Tong et al. , 2019). In addition, CaMg(CO ₃ ) _{2 The} higher the pH, and the lower Eq. It is known to decompose into _{CaCO 3} through the chemical reaction of 1.

CaMg(CO ₃ ) ₂ + 2MOH → M ₂ CO ₃ + Mg(OH) ₂ + CaCO ₃ (Eq. 1)

* M = Na, K, or Li.

In order to evaluate the removal performance of PO ₄ -P and NH ₃ -N of calcined oyster shells and microalgae ( Chlorella vulgaris ), the “waste process” presented by the Ministry of Environment using an upflow permeable outflow device shown in the schematic diagram in FIG. An upflow permeable runoff test was performed in "Test Standards" (MOE, 2016).

In this experiment, a 20 L storage container, a metering tube pump (BT600-2J, LONGER PUMP), and a 13 L container were used for the sample filling layer. 「9. Ventilation pipe” and “10. The stopper of the collection container was removed, and “12. When the effluent flows into the collection container, it was immediately collected and analyzed.

In the upflow permeable outflow device, refer to 「1. The storage container” was filled with artificial sewage water. Artificial sewage is obtained _{by mixing NH 4} Cl (Ammonium chloride, Sigma-Aldrich, Spain) and KH ₂ PO ₄ (Potassium phosphate monobasic, Sigma-Aldrich, Japan) with _{tertiary distilled water to obtain PO 4} -P and NH ₃ -N concentrations. Each was prepared to be 25 mg/L.

Table 2 below shows the amounts of POS100, POS600, and POS800 used in the experiment and the inflow of artificial sewage. About 866 g ~ 982 g of calcined oyster shells were used, and the inflow of artificial sewage was found to be in the range of 650 mL to 900 mL. After filling the calcined oyster shells in the sample filling layer, the artificial sewage inflow was set to flow as much as the remaining voids in the sample filling layer. The difference in the calcined oyster shells and the capacity of the introduced artificial sewage is due to the difference in the average particle diameter of the different oyster shells for each experimental case and the voids due to consolidation that occurred while the oyster shells were filled in the sample filling layer. Artificial sewage was set to flow out after staying in the sample-filled bed for 6 hours with reference to the sewage design standards announced by the Ministry of Environment (MOE, 2017). In addition, it was set so that new artificial sewage flows in while the artificial sewage flows out from the sample filling layer. Experiments up to 33 times of POS100, 52 times of POS600, and 56 times of POS800 were repeatedly performed.

PO ₄ -P and NH ₃ -N were analyzed using an automatic analyzer (DR 3900, Hach), and each analysis item was analyzed three times.

<Table 2> Amount of oyster shells and artificial sewage inflow used in upflow permeable runoff test

Removing amount (mg) of PO ₄ -P accordance with the concentration of the artificial sewage PO ₄ -P (FIG. 4 (a)) and a fill weight (g) of POS100, POS600, POS800 in oil, out in Figure 4 (FIG. 4(b)) is shown. _{The PO 4} -P concentration of the initial effluent decreased by about 53% for POS100, 62% for POS600, and 100% for POS800 compared to the influent. Ca eluted from calcined oyster shells was the cause of the decrease in Eq. It is considered that _{PO 4} -P was immobilized through a chemical reaction such as 3 to 6.

Ca ²⁺ + HPO ₄ ^2- → CaHPO ₄ ↓ (Eq. 3)

Ca2+ + 2PO ₄ ^3- → Ca(PO ₄ ) ₂ ↓ (Eq. 4)

Ca2+ + 2H ₂ PO ₄ ^- → Ca(H ₂ PO ₄ ) ₂ ↓ (Eq. 5)

Ca2+ + 3HPO ₄ ^2- + 4OH ^- → Ca ₅ (OH)(PO ₄ ) ₃ ↓ + 3H ₂ O (Eq. 6)

According to previous studies, CaMg(CO ₃ ) ₂ has a property of having low pores and a homogeneous surface, but it is known that it has a property of adsorbing _{PO 4 -P, so CaMg(CO 3} ) ₂ Adsorption of PO _{4 -P by CaMg(CO 3 ) 2} It is also considered to be contributing to the reduction of the _{PO 4 -P concentration.}

_{The PO 4} -P concentration in the POS100 effluent was in the range of 11.5 to 2 mg/L, and it continued to decrease as the number of repetitions increased. Unlike POS600 and POS800, POS100 had a low calcination temperature and thus a small amount of Ca generated in the calcination process, so that the phosphate removal rate was initially low. _{The PO 4} -P concentration in the POS800 effluent was found to maintain a removal amount of about 0.015 mg/g. According to previous studies, when oyster shells are heated to 100℃, the weight decreases gently due to evaporation of moisture remaining in oyster shells and decomposition of organic matter, but at 761.5℃, it is known that about 47.5% weight reduction occurs and high purity CaO is produced. Considering that, POS800 has a higher CaO content than POS100 and POS600, so the phosphate removal efficiency is the highest.

On the other hand, the POS600 effluent PO ₄ -P concentration was initially about 9.5 mg/L, which was lower than that of POS100, but at the 28th time, the concentration increased and reached 25 mg/L, indicating that there was no difference with the inflow artificial sewage.

Compared to POS100 and POS800, POS600 uses 1.12 to 1.38 times more influent and 0.88 to 0.96 times more oyster shells, so it is judged that the amount of PO ₄ -P removed is relatively low. In Fig. 4(b), POS100 shows a higher removal amount than POS600 and POS800. In the results of previous studies, it has been reported that when oyster shells are calcined, Na ⁺ trapped in oyster shells agglomerate particles and reduce the specific surface area. That is, the PO ₄ -P removal amount in the order of POS100, POS800, and POS600 is considered to be due to the complex effects of the difference in specific surface area, purity of Ca produced, and the difference in the amount of influent and oyster shells.

From the above results, it was possible to confirm the effect of removing _{PO 4 -P using calcined oyster shells.}

Figure 5 is a result of measuring the NH ₃ -N removal performance of microalgae ( Chlorella vulgaris ) in the present Example. Referring to FIG. 5 , as a result of the experiment using microalgae, the removal rate of ammonium showed a high tendency compared to the control. From 3 days after the start of the experiment, it was confirmed that the removal efficiency of the ammonium concentration was 90% or more, and the removal rate was about 2 times higher than that of the control group. These results are judged to be the result of oxidation of ammonium due to oxygen produced through absorption of ammonium by microalgae and photosynthesis of microalgae.

The present invention is not limited to the above embodiments, but can be manufactured in a variety of different forms, and those of ordinary skill in the art to which the present invention pertains can take other specific forms without changing the technical spirit or essential features of the present invention. It will be understood that it can be implemented as Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (6)

(A) crushing the oyster shell; and
(B) after calcining the oyster shell, attaching microalgae to the oyster shell to prepare a sewage treatment material,
A method of manufacturing a sewage treatment material for removing _{PO 4} -P and NH _{3 -N.} According to claim 1,
The microalgae are Chlorella vulgaris ( Chlorella vulgaris ), Arthrospira platensis ( Arthrospira platensis ), Ankistrodesmus gracilis ( Ankistrodesmus gracilis ), Senedesmus Accuinatus ( Scenedesmus accuminatus ) and Senedesmus Quadricauda ( Scenedesmus quadricauda ) A method of manufacturing a sewage treatment material for removing _{PO 4} -P and NH ₃ -N, characterized in that at least one selected from the group consisting of. According to claim 1,
(a) crushing the oyster shell;
(b) calcining the oyster shells at 100° C. and then attaching microalgae to the oyster shells to prepare a first sewage treatment material;
(c) calcining the oyster shells at 600 to 800° C. and then attaching microalgae to the oyster shells to prepare a second sewage treatment material; and
(d) mixing the first sewage treatment material and the second sewage treatment material;
A method of manufacturing a sewage treatment material for removing _{PO 4} -P and NH _{3 -N.} 4. The method of claim 3,
In the step (d), the first sewage treatment material and the second sewage treatment material are mixed in a weight ratio of more than 0: 10 and less than 10: 0, PO ₄ -P and NH ₃ -N of a sewage treatment material for removal manufacturing method. A sewage treatment material for removing _{PO 4} -P and NH ₃ -N manufactured by the method according to any one of claims 1 to 4. A sewage treatment system comprising an aeration tank or a sample-filled bed filled with a sewage treatment material for removing _{PO 4} -P and NH ₃ -N according to claim 5.

Images