KR100316298B1 - Fiber Membrane Separation and Activated Sludge Process with Electrolytic Treatement Process of Animal WasteWater - Google Patents

Abstract

The present invention relates to an advanced treatment method for livestock wastewater for proper treatment of high concentration malignant livestock wastewater generated in livestock facilities such as pig farms, by developing a livestock wastewater treatment method combining membrane separation activated sludge method and electrolysis method. It is aimed at perfecting the treatment and contributing to environmental protection. In general, livestock wastewater has a very high BOD load rate and is difficult to treat because of increased COD load rate, SS concentration, and color due to overuse of antibiotics and disinfectants. Since the chemical treatment method is not able to obtain a stable and complete treatment efficiency, the present invention has developed a method for treating livestock wastewater combining membrane separation type activated sludge method and electrolysis method.

The method for treating livestock wastewater combining membrane separation type activated sludge method and electrolysis method of the present invention is to raise the concentration of BOD, COD, nitrogen and phosphorus in livestock wastewater to a concentration that can maximize the efficiency of electrolysis using biological treatment and hollow fiber membrane principle. It is an advanced treatment method that removes lead decomposable substances and suspended solids, and Urobirin, which causes color, by primary treatment and electrolysis, and is inexpensive compared with conventional biological and physicochemical treatment methods. The treated water quality is stable, bacteria can be removed, it can be operated at high MLSS concentration, and it is not affected by sludge settling and sludge bulking phenomenon.

Description

Fiber Membrane Separation and Activated Sludge Process with Electrolytic Treatement Process of Animal WasteWater

The present invention relates to a method for treating livestock wastewater combining membrane separation type activated sludge method and electrolysis method, and by raising fundamentally improving water pollution of groundwater or intake source caused by high concentration malignant wastewater generated in various livestock farms including pig farms. The present invention relates to a method of treating livestock wastewater, which contributes to environmental protection by perfecting wastewater treatment.

Due to the high concentration of malignant livestock wastewater generated from industrial wastewater, especially livestock facilities such as pig farms scattered within the water supply protection area, the water quality of groundwater and intake sources is extremely polluted and deteriorated. Livestock wastewater contains a large amount of nutrients such as nitrogen and phosphorus, resulting in red tide in rivers and lakes due to eutrophication. However, livestock wastewater from pig farms, etc. Even without proper treatment, the situation is stepless discharge. In order to solve such a problem, a method of treating livestock wastewater was developed by combining membrane separation type activated sludge method and electrolysis method.

Livestock wastewater has a very high BOD load rate, increases COD load due to overuse of antibiotics and disinfectants, and is difficult to treat because of high SS concentration and color. Biological treatments and physicochemical treatments such as fenton oxidation, UV AOP, and sawdust fermentation are processed in parallel, but in this case, microorganisms are sensitive to temperature and are affected by seasonal effects, making it difficult to process stable sludge such as bulking. In addition, it is not easy to cope with the change of influent concentration. Especially in the case of wastewater with high nitrogen concentration such as livestock wastewater, treatment efficiency is reduced by the appearance of toxic microorganisms, so it is highly resistant to malignant wastewater such as livestock wastewater from pig farms. Altitude of livestock wastewater due to insufficient treatment The re-development of technology has been keenly desired.

In addition, when the physicochemical method is used, the treatment cost is high, the treatment efficiency is lowered, and the chemical sludge is used, so the sludge produced is the cause of the secondary pollution. Many.

In order to solve the above problems, the present invention combines the membrane separation type activated sludge method and the electrolysis method, and has developed a technology for treating livestock wastewater.

The method for treating livestock wastewater combining membrane separation type activated sludge method and electrolysis method of the present invention is electrolysis of high concentrations of BOD, COD and organic nitrogen contained in livestock wastewater by membrane separation type activated sludge method using biological treatment and hollow fiber membrane principle. After the first treatment to a low concentration to maximize the action, the electrolytic method is used to remove hardly decomposable substances, suspended solids, and the color of the urobirin (Urobirin). In other words, the hollow fiber membrane, a high-precision high-tech material filter that completely filters impurities in the water, is directly installed to remove BOD, COD load and ammonia, and then it is put into an electrolysis tank to remove it from the membrane separation type activated sludge method. By removing insoluble hardly decomposable substances, COD, heavy metals, nitrogen and phosphorus, it is possible to obtain stable and perfect processing efficiency.

1 is a wastewater treatment process diagram of the present invention

<Explanation of symbols for main parts of drawing>

1: collection tank 2: pressurization tank 3: aeration tank 4: electrolytic tank 5; sedimentation tank

6: A / C adsorption tank 7: Concentration tank 8: Dehydrator

The present invention is the first treatment of livestock wastewater containing high concentrations of BOD, COD and organic nitrogen to a low concentration so as to maximize the electrolysis by the conventional biological treatment and membrane separation activated sludge method using a hollow fiber membrane The decomposition method removes urobirin (UROBIRIN), which is a cause of hardly decomposable substances, suspended solids and chromaticity.

The membrane-separated activated sludge method according to the present invention uses biological treatment and the principle of hollow fiber membrane, and directly immerses the activated sludge treatment device, which is a filter module in which an ultra-precision hollow fiber membrane is fixed in the form of a screen, in an aeration tank to remove organic substances that are aerobic microorganisms in wastewater. It is a system that separates MLSS (float of mixed liquid in aeration tank) and treated water generated by activated sludge method, which is decomposed and treated by pump suction from outside of hollow fiber membrane (pore diameter: 0.1 µm) to the inside. The membrane is installed in the pressure pipe to form a filtration module, and because the pressure source used as a dry finger hose is used, if the SS (float) concentration is high, the blockage on the membrane surface and membrane surface due to the sediment rapidly progresses to solid-liquid separation. Solid liquid separation of activated sludge and river water, high turbidity of raw water because it cannot be stably performed for a long time However, the hollow fiber membrane for solid-liquid separation membrane is a membrane in which the hollow fiber membrane is fixed in the screen state, and since the pressure-resistant tube is not required, the membrane is supplemented with the disadvantages of the existing membrane. More than 99% of the particles can be removed. In the membrane separation type activated sludge method of the present invention, a separation section capable of forming turbulent flow in the aeration tank is prevented from attaching the activated sludge to the membrane surface or the module by aeration in the separation section. There is no outflow, so organic matter treatment efficiency is good, and intermittent nitrification and denitrification occur simultaneously, so it is excellent in total nitrogen removal efficiency. In addition, by aeration of excess sludge without organic material for a long time, the cells are endogenous respiration and self-oxidation, the sludge is decomposed to reduce the sludge amount.

In addition, there is no recirculation of sludge, so hydraulic retention time (HRT) and microorganism stay in aeration tank (SRT) are the same.

The reaction scheme by the electrolytic oxidation of the electrolytic treatment method of the present invention is as follows.

At the anode, organic matter is forcibly oxidized by oxygen generated by the reaction schemes 1 and 2, and the COD and BOD of the wastewater are reduced.

_{2H 2 0 → 0 2 + 4e} - + 4H +

_{^{40H - → 2H 2 O + 02}} ↑ + 4e -

In addition, the electrolysis method of the present invention is a method of purifying the waste water by causing an electrolysis reaction by supplying electrical energy to the waste water mixed with an inorganic or organic electrolyte from the outside, the oxidation and reduction (10 ^-l3 / second) occurs continuously Oxidation, reduction, decomposition, and precipitation occur, and at the interface between the electrode and the wastewater, the electrode reaction and the electrode reaction product interact with the constituents in the wastewater, causing the secondary reaction to occur, and the organic matter is forcibly oxidized by oxygen generated at the anode. Due to electrooxidation, COD and BOD decrease, and due to the precipitation or precipitation of hydroxides such as metal ions (Fe ³⁺ ) eluted from soluble anodes such as iron or aluminum In the waste water by the action of electrocoagulation such as flocculation sedimentation of suspended solids, decomposition of organic matter by OH and radical generated from cathode The SS and the contaminants is removed.

The reaction scheme by the electrolytic coagulation of the electrolytic treatment method of the present invention is as follows.

In the case of using a soluble anode such as iron or aluminum, as the metal ions eluted from the anode combine with OH ^- groups in water to form metal hydroxides, not only flocculates suspended matter in water, but also precipitates or floats together. SS and contaminants in the drainage are removed by adsorbing dissolved organics to the resulting floc.

Electrolytic coagulation at the electrode of iron or aluminum is as follows.

Anode Reaction:

Fe → Fe ²⁺ + 2e ^-

Al → Al ³⁺ + 3e ^-

Precipitation reaction:

^{Fe 2+ + 20H - → Fe (} OH) 2 ↓

^{Al 3+ + 30H - → Al (} OH) 3 ↓ (B)

At this time, the metal hydroxide produced is stronger than the chemically produced metal hydroxide and has a low zeta potential, so the flocculation, adsorption, and sedimentation are very good.

Hydrous metal oxide also combines with various compounds on the surface and simultaneously bears positive and negative charges on the surface, so that the soluble components contained in the wastewater can be removed by the attraction of the opposite charge.

The membrane separation activated sludge method of the present invention and the method of treating livestock wastewater in connection with electrolysis will be described in more detail as follows.

The present invention primarily treats the concentrations of high BOD, COD, nitrogen and phosphorus in livestock wastewater to a concentration that can maximize the efficiency of electrolysis using biological treatment and hollow fiber membrane principle, and lead-degradable materials using electrolysis; Advanced treatment of wastewater to remove urovirin, which is a source of suspended solids, nitrogen, phosphorus and color. In other words, immersion of the hollow fiber membrane, a high-precision high-tech material filter that completely filters MLSS, in the aeration tank to remove BOD, COD load and ammonia components first, and then it is not possible to remove them by membrane separation type activated sludge method by introducing wastewater into the electrolysis tank. By removing decomposable substances, COD, heavy metals, nitrogen and phosphorus, stable and perfect processing efficiency can be obtained.

In addition, the principle of treating and removing contaminants such as BOD, COD, SS, and chromaticity, which are the sources of livestock wastewater, by the electrolysis method of the present invention is as follows.

1) electrode reaction

When iron or aluminum is used, the reaction occurs at the anode and cathode as shown in the following reaction formula.

anode:

_{2H 2 0 → 0 2 + 4e} - + 4H +

Scheme 2

_{^{40H - → 2H 2 O + O}} 2 ↑ + 4e -

^{_{Fe (S) → Fe 2+ +}} 2e -

^{_{Fe (S) → Fe 3+ +}} 2e -

^{_{Al (S) → Al 3+ +}} 3e -

cathode:

2H ^{+ +} 2e ^- → H ₂

_{↑ + 20H 2H 2 O → H} 2 -

Iron ions eluted by Schemes 8 and 9 react with OH ⁻ generated at the cathode by Scheme 8 to form iron hydroxide precipitates, as shown in Schemes 13 and 14.

^{Fe 2+ + 20H - → Fe (} OH) 2 ↓

^{Fe 3+ + 30H - → Fe (} OH) 2 ↓

Even when an aluminum electrode is used as the anode, aluminum hydroxide precipitates are produced by the same principle.

^{Al 3+ + 30H - → Al (} OH) 3 ↓

2) COD and BOD Removal

COD and BOD removal of waste water by electrolysis is by electrolytic oxidation and the process is as follows.

Oxygen is generated at the anode as in Equation 2, and the oxygen generated at this time is very small in size so that the oxygen delivery speed to the wastewater is fast, so oxygen supply is good and the oxygen absorbed in the wastewater treats COD and BOD causative agents.

Scheme 2

_{^{40H - → 2H 2 O + O}} 2 ↑ + 4e -

Since OH radicals generated at the cathode also have the ability to oxidize and decompose organic matters, polymer organic matters are decomposed into low-molecular organic matters that can be effectively treated, and decomposed polymer organic matters are oxidized by oxygen, which effectively removes BOD and COD from wastewater. . In addition, BOD and COD are also reduced because iron or aluminum ions eluted at the anode co-precipitate the view oily materials when precipitated with hydroxides.

3) SS removal

SS by electrolysis is caused by electrolytic coagulation and the process is as follows.

Iron or aluminum ions eluted at the anode react with OH ⁻ generated at the cathode by Scheme 12 to form hydroxide precipitates as shown in Schemes 13, 14 and 15.

Scheme 13

^{Fe 2+ + 20H - → Fe (} OH) 2 ↓

Scheme 14

^{Fe 3+ + 30H - → Fe (} OH) 2 ↓

Scheme 15

^{Al 3+ + 30H - → Al (} OH) 3 ↓

At this time, the metal hydroxide produced is precipitated because the solubility product is very small. In particular, it is known that precipitation occurs most favorably in the neutral region, and the metal hydroxide produced by electrocoagulation is more active than the chemically produced metal hydroxide. Due to the strong and low zeta potentia, the flocculation, adsorption, and sedimentation characteristics are very good.

4) Nitrogen and Phosphorus Removal

The livestock wastewater contains a large amount of nitrogen and phosphorus. In the case of biological treatment, the ratio of BOD: N: P must be adjusted for efficient treatment. Therefore, phosphorus and nitrogen may be added from the outside, so the concentration of nitrogen and phosphorus in the treated water In some cases, the concentration of raw wastewater may be higher than that, which would lead to eutrophication of streams and lakes and red tides in the Inland Sea if phosphorus and nitrogen are not treated efficiently.

The process of nitrogen and phosphorus removal using electrolysis is as follows.

1) Removal of phosphorus

In the electrochemical treatment, the iron and aluminum ions produced at the anode react with phosphate ions in the wastewater at high speed to form phosphate precipitates, which are precipitated and removed.

3Fe ²⁺ + 2PO ₄ ^3- → Fe (PO ₄ ) ₂ ↓

Fe ³⁺ + PO ₄ ^3- → FePO ₄ ↓

Al ³⁺ + PO ₄ ^3- → AlPO ₄ ↓ (K ^SP = 10 ^-21 )

At this time, since the metal ion-phosphate precipitate formed has a very low solubility, precipitation is easily formed, and the solid-liquid separation completely removes the phosphate ion.

The physical effect is that the phosphate ions are adsorbed and removed by the positive charge carried out when the iron or aluminum ions eluted from the anode are precipitated with a complex hydroxide.

2) removal of nitrogen

Nitrogen compounds present in SS or colloidal state are removed by electrolytic coagulation, and soluble organic nitrogen compounds are oxidized to nitrogen compound form by electrolytic oxidation and then reduced and removed by electrolysis as shown in the following reaction formula.

_{^{NO 3 - + 6H + + 5e}} - → 3H 2 O + N2 ↑

Referring to the accompanying drawings, the operation of the membrane separation type activated sludge method of the present invention and the method for treating livestock wastewater in connection with electrolysis are as follows.

Raw water introduced into the sump (1) is introduced into the aeration tank (3) after the solid-liquid separation through the pressure flotation tank (2). Inflowed wastewater is aerobic microorganisms in the wastewater in the aeration tank (3) to decompose organic matter and BOD, COD and nitrate are treated. At this time, the return sludge process of the settling tank, which is essential for the existing standard activated sludge process, is eliminated, and the organic matter treatment efficiency is increased by increasing the MLSS concentration in the aeration tank. Wastewater whose concentration is adjusted to maximize the efficiency of electrolysis through primary treatment through aeration tank (3) is hardly decomposable material, COD, heavy metals and nitrogen that were not removed by membrane separation type activated sludge method, which is a pretreatment process. , Phosphorus is removed. In the electrolyzer 4, oxidation, reduction, decomposition, precipitation, and the like occur, and at the interface between the electrode and the wastewater, the electrode reaction and the electrode reaction product react with the components in the wastewater, so that the secondary reaction occurs, and the electrolytic oxidation reaction causes the COD of the wastewater. And BOD, nitrogen and phosphorus are reduced and SS in the wastewater is removed by the electrocoagulation reaction. In addition, phosphorus and nitrogen contained in the waste water are formed by iron or aluminum ions produced at the anode during electrolysis as phosphate compounds and precipitated at a high rate with phosphate ions in the waste water, and iron or aluminum ions eluted at the anode during the secondary reaction. Phosphate ions are adsorbed and removed by the positive charges present when precipitated with complex hydroxides. Nitrogen compounds present in SS or colloidal state are removed by electrolytic coagulation, and soluble organic nitrogen compounds are oxidized to nitrogen compound form by electrolytic oxidation and then reduced and removed by electrolysis. The treated water treated in the electrolytic cell 4 is introduced into the settling tank 5, and the sludge is settled, and when the separated water is finally processed through the AC adsorption tank, it is reused as cleaning water. On the other hand, the slurry separated in the pressure flotation tank (2) is concentrated in the concentration tank (7), dehydrated in the dehydrator (8) and the dewatered sludge CAKE is composted.

The following is an example using the treatment method of livestock wastewater combining membrane separation type activated sludge method and electrolysis method of the present invention.

Example 1

end. Efficiency comparison before and after treatment

* Treatment standards are based on water quality by the Water Act.

I. Operating cost comparison (sawdust fermentation and the invention)

All. Treatment Efficiency (Korea Testing and Research Institute)

Therefore, when comparing the embodiment using the sawdust fermentation formula and the method of treating livestock wastewater combined with the membrane separation activated sludge method of the present invention and electrolysis method, it can be seen that the efficiency and operating cost before and after the wastewater treatment.

The present invention combines membrane separation activated sludge method and electrolysis method to treat livestock wastewater, and then firstly treats high concentrations of BOD, COD, nitrogen and phosphorus in livestock wastewater to the extent that the efficiency of electrolysis can be maximized. By removing highly degradable substances, urovirin (Urobirin), which is the cause of suspended solids, nitrogen, phosphorus and chromaticity, it is possible to completely treat livestock wastewater generated in animal husbandry facilities such as pig farms. When wastewater is treated, the area of equipment is reduced, operation costs are reduced, and it is safely and completely treated without being affected by climate change, and color, heavy metals, E. coli are completely removed, and bacteria can be removed, and even at high MLSS concentrations. Operation is possible and is not affected by sludge settling and sludge bulking phenomenon.

In addition, in the general wastewater treatment, a large amount of flocculant must be administered to remove SS. However, in the wastewater treatment method using the electrolysis method, the coagulant is not required because the metal ion (iron or aluminum) eluted from the anode serves as a flocculant. In the case of administering flocculant by the general method, PH adjustment is required, but electrolytic coagulation by electrolysis occurs best in the neutral region of iron or aluminum hydroxide, so the initial pH and electrolysis time are adjusted to neutralize the water quality. It is a very economical and excellent treatment method for livestock wastewater because it can be precipitated without PH adjustment and PH consumption of treated water can be reduced because it is reduced.

Claims (1)

Livestock wastewater containing high concentrations of BOD, COD, nitrogen, and phosphorus is pretreated at low concentrations to maximize electrolysis by biochemical treatment and membrane-separated activated sludge method using hollow fiber membranes. In the advanced treatment of wastewater and wastewater, which removes UROBIRIN, which is a cause of hardly decomposable substances, suspended solids and chromaticity, the membrane-separated activated sludge method fixes a solid-fiber membrane for solid-liquid separation in an aeration tank to form a turbulent flow. Livestock combined with membrane separation activated sludge method and electrolysis method, characterized by pretreatment of high concentration of wastewater by separating the sludge and treated water by filtration by suction by intermittently in the separation section with a separation section capable of forming Treatment of waste water.