CN101007684A - Anerobic ammoxidation and denitrification synergistic denitrification method for garbage leachate - Google Patents

Abstract

The invention discloses a method for synergistic denitrification of landfill leachate by anaerobic ammonium oxidation and denitrification. This method firstly mixes waste water to be treated with water containing nitrate nitrogen, so that the waste water to be treated becomes organic waste water containing COD, NH ₄ ⁺ , NO ₂ ^- and NO ₃ ^- , and then the organic waste water is introduced into activated sludge and landfill infiltration. The anaerobic sludge bed where the filtrate is enriched and domesticated by anammox bacteria and denitrifying bacteria can treat COD, NH ₄ ⁺ , NO ₂ ^- or NO ₃ ^- in organic wastewater through anammox bacteria and denitrifying bacteria The synergistic effect of COD, ammonia nitrogen and nitrate nitrogen is removed simultaneously, and the temperature of the anaerobic sludge bed treated wastewater is controlled at 26-36 °C. In the organic environment, the present invention can successfully realize the anaerobic ammonium oxidation reaction, and also successfully realize the denitrification reaction, so that excess nitrate nitrogen can be turned into nitrogen gas through denitrification, which can not only completely remove nitrogen, but also remove part of COD. It has important engineering application value.

Description

A method for synergistic denitrification of landfill leachate by anaerobic ammonium oxidation and denitrification

technical field

The invention relates to a method for synergistic denitrification of landfill leachate by anaerobic ammonium oxidation and denitrification. Specifically, an improved anaerobic sludge bed reactor is used to domesticate aerobic and anaerobic activated sludge through landfill leachate at the same time. The landfill leachate is passed into the bioreactor, and the synergistic effect of anaerobic ammonium oxidation and denitrification of the microbial system is used to promote the removal of NH ₄ ⁺ and NO ₂ ^- by anaerobic ammonium oxidation in the bioreactor, and through denitrification Function to remove NO ₃ ^- and organic pollutants (COD) produced by anaerobic ammonium oxidation.

Background technique

In 1977, Broda speculated that there may be two kinds of autotrophic microorganisms that can oxidize NH ₄ ⁺ into N ₂ in nature based on the calculation of free energy of thermodynamic reaction. In 1994, Mulder et al. found that NH ₄ ⁺ disappeared in a sewage denitrification fluidized bed reactor at Deflt University in the Netherlands, and N ₂ was generated with the consumption of NH ₄ ⁺ and NO ₃ ^- . Because ammonia nitrogen is oxidized under anaerobic conditions, it is called anaerobic ammonia oxidation (ANAMMOX-Anaerobic AMMoniaOxidation). Subsequent experiments confirmed the redox reaction with NH ₄ ⁺ as electron donor and NO ₃ ^- as electron acceptor through N balance and redox balance, thus confirming Broda's conjecture.

So far, there are dozens of foreign and domestic research documents on the ANAMMOX reaction process. The measurement equation reported was obtained by Van der Heijiden et al. in 1994 by calculating the ANAMMOX test data of nearly 200 days, such as formula (1) Shown:

NH ₄ ⁺ +1.32NO ₂ ^- +0.0066HCO ₃ ^- +0.13H ⁺ →0.0066CH ₂ O _0.5 N _0.15 +1.02N ₂ ↑

+0.26NO ₃ ^- +2.03 H ₂ O (1)

In the formula, CH ₂ O _0.5 N _0.15 is the cell molecular formula (empirical formula) of ANAMMOX bacteria.

The inventor adopts a self-created electronic metrology method, using NH ₄ ⁺ as the electron donor and NO ₂ ^- as the electron acceptor, assuming that the cell molecular formula of ANAMMOX bacteria is C _α H _β O _ε N _δ , and the electron donor Since the component synthesized by cells is f _s and the source of nitrogen synthesized is NO ₂ ^- , the electrometric equation of anaerobic ammonium oxidation reaction is deduced as:

Compared with the traditional nitrification and denitrification process or simultaneous nitrification and denitrification process, anammox has outstanding advantages. The main performances are: (1) No need to add organic matter as electron donor, which can save costs and prevent secondary pollution; (2) Nitrification reaction per oxidizes 1mol NH ₄ ⁺ consumes 2mol of oxygen, while in anaerobic ammonium oxidation reaction , only 0.75mol oxygen is needed for every 1mol NH ₄ ⁺ oxidized, and the oxygen consumption drops by 62.5% (when cell synthesis is not considered), so the oxygen consumption and energy consumption can be greatly reduced; (3) The traditional nitrification reaction can produce 1mol NH ₄ ⁺ 2molH ⁺ , denitrification and reduction of 1molNO ₃ ^- or NO ₃ ^- will produce 1molOH ^- , while the biological acid production of anaerobic ammonium oxidation is greatly reduced, and the production of alkali is reduced to zero, which can save considerable neutralization reagents.

The denitrification reaction is under anaerobic conditions. The denitrifying bacteria use organic matter (nitrogen-containing organic matter C _a H _b O _c N _d , hydrocarbons C _a H _b O _c , organic acids C _a H _b O _c ^- , etc.) Electron donor, using NO ₃ ^- and NO ₂ ^- as electron acceptors, the process of finally converting nitrate nitrogen into N ₂ . The general formula of the electronic metrology response is:

The COD/N ratios required for the reaction are:

$\frac{\mathrm{<span\; class="notranslate">\; COD</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="3"\; label="NO"\; filenames="A20071002641800091.png"\; state="\{\{state\}\}">NO</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 2.86</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1.628</span>}\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

$\frac{\mathrm{<span\; class="notranslate">\; COD</span>}}{\mathrm{<span\; class="notranslate">\; N</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="NO"\; filenames="A20071002641800091.png,A20071002641800101.png"\; state="\{\{state\}\}">NO</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1.714</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1.628</span>}\mathrm{<span\; class="notranslate">\; Y</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

So far, domestic and foreign studies on ANAMMOX biological denitrification mostly use ammonium salt and nitrite artificial water distribution to carry out small-scale experiments, and have achieved success and high treatment efficiency _. ⁺ and NO ₂ ^- in the ANAMMOX process will produce a certain amount of NO ₃ ^- , so, in the organic environment, two main anaerobic denitrification reactions, anaerobic ammonia oxidation and denitrification, may exist at the same time.

The electronic metrology analysis of ANAMMOX reaction and denitrification reaction shows that: ANAMMOX reaction consumes inorganic carbon source CO ₂ and produces a certain amount of NO ₃ ^- ; while denitrification reaction consumes organic carbon source (COD), but produces CO ₂ , It can provide a certain carbon source for ANAMMOX reaction, which is beneficial to the progress of ANAMMOX. Therefore, if the synergistic effect of anammox and denitrification can be realized in the same reactor system, it will be of great significance to the development of new technologies for biological nitrogen removal.

Contents of the invention

The purpose of the present invention is to provide a synergistic denitrification method of anaerobic ammonium oxidation and denitrification of landfill leachate, aiming at the shortcoming that domestic and foreign anammox research is mainly limited to small-scale experiments with artificial water distribution of ammonia salt and nitrite.

In order to achieve the above-mentioned purpose of the invention, the present invention has taken the following technical solutions:

A method for synergistic denitrification of landfill leachate by anaerobic ammonium oxidation and denitrification _: firstly _, the waste water ^to be treated is mixed with water containing nitrate ^nitrogen , so that the ^waste water to be _treated becomes organic wastewater, and then the organic wastewater enters the anaerobic sludge bed that introduces activated sludge and landfill leachate to enrich and domesticate anammox bacteria and denitrifying bacteria, and treat COD, NH ₄ ⁺ , NO ₂ ^- or NO ₃ ^- synergistically removes COD, ammonia nitrogen and nitrate nitrogen through the synergistic effect of anammox bacteria and denitrifying bacteria, and the temperature of wastewater treated by anaerobic sludge bed is controlled at 26-36°C.

First for the advantages of the prior art the present invention has:

The present invention adds the waste water prepared by activated sludge and landfill leachate into the bioreactor, and what is obviously different from the technology that has been reported both at home and abroad so far is: the waste water studied by the prior art does not contain organic matter substantially, and the test water of the present invention Contains a large amount of organic matter-COD (this can better meet the actual requirements of environmental engineering). The invention adopts specially treated sludge domestication, and can realize the synergistic effect of anaerobic ammonium oxidation and denitrification of landfill leachate in an anaerobic sludge bed reactor under an organic environment. In the stable stage of anammox activity (starting from 120d), the average removal rates of ammonia nitrogen and nitrite nitrogen were 94.79% and 98.17% respectively; the highest removal rate of COD could reach 51.68%. The removal rate was 23.51%, and the corresponding average volume removal load was 84.53mg/(L.d). After entering the stable operation stage, from the 19th day to the 57th day, the ratio of nitrite nitrogen removal to ammonia nitrogen removal fluctuated between 2.77 and 7.67, and the average ratio was 4.17, which was much higher than the 1.32 reported in the literature. Strong denitrification reaction. From the 58th day to the 125th day, the ratio of nitrite nitrogen removal to ammonia nitrogen removal fluctuated between 1.17 and 3.28, and the average ratio was 2.03, which was still higher than the 1.32 reported in the literature, indicating that there was a certain denitrification reaction. From the 128th day to the 202nd day, the ratio of nitrite nitrogen removal to ammonia nitrogen removal fluctuated between 1.22 and 1.64, and the average ratio was 1.37, which was quite close to the 1.32 reported in the literature in the inorganic environment. It shows that in an organic environment, the anammox reactor can successfully realize the anammox reaction and denitrification reaction at the same time, so that excess nitrate nitrogen can be turned into nitrogen gas through denitrification, which not only completely removes nitrogen, but also A part of COD can be removed. It solves the international problems in this field and has important engineering application value.

Description of drawings

Fig. 1 is the structural representation and flow process of the anaerobic sludge bed bioreactor used in the present invention;

Fig. 2 is the rapid removal effect of the method used in the present invention to ammonia nitrogen;

Fig. 3 is the NO ₂ ^- -N removal effect of the method used in the present invention;

Fig. 4 is the variation of NO ₂ ^- -N/NH ₄ ⁺ -N ratio of NO ₂ ^- -N by the method used in the present invention;

Figure 5 is the effect of the method used in the present invention on the COD removal of waste water.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings, but the scope of protection claimed by the present invention is not limited to the scope described in the specific embodiments.

The test device that the present invention adopts is as shown in accompanying drawing 1, and anammox reactor comprises cylindrical reactor shell 1, and the bottom in shell 1 is provided with anaerobic sludge bed 2, and shell 1 bottom has The water inlet 7 and the water inlet 7 are connected to the water distribution tank 5 through the pump 6, the upper part of the cylinder is provided with a water outlet 3, and a constant temperature control system 4 is provided around the anaerobic sludge bed 2 outside the anaerobic ammonium oxidation reactor. The device is changed into a circular shape, and the three-phase separator is canceled on the upper part, and a constant temperature control system is set outside the anaerobic sludge bed. The anaerobic sludge bed 2 is obtained by adding activated sludge and landfill leachate into the reactor, anaerobic domestication, and cultivating anammox bacteria and denitrifying bacteria.

The test wastewater was taken from the distribution pool of a landfill in Guangdong. In order to alleviate the impact of immediate water distribution on the activated sludge, the landfill leachate and the effluent of the SBR reaction tank (1500m ³ ) were mixed as anaerobic ammonia before the 18th day. Oxidize the water in the reactor to make it contain NH ₄ ⁺ , COD, NO ₂ ^- and NO ₃ ^- . After the 19th day, dilute the landfill leachate with tap water to the appropriate concentration of ammonia nitrogen in the reactor, and add an appropriate amount of sodium nitrite to Provides the electron acceptor required for anammox. The test adopts low concentration and low load start-up method for domestication. The temperature of the anaerobic sludge bed treated wastewater is controlled at 30°C, and it has been operated for 203 days. The reactor start-up and operation results are shown in Figure 2-5.

The sludge was taken from a landfill in Guangdong while the leachate was treated with aerobic and anaerobic treatment of activated sludge. The sludge is reddish-brown, and ordinary optical microscope examination shows that the sludge structure is finely divided, with bell worms, larvae and rotifers, and few filamentous bacteria. The MLSS is 15.4g/L, and the inoculum size is 1-3L, which is 65% of the effective volume of the reactor.

Implementation Effect:

1. Nitrogen removal effect of anaerobic ammonia oxidation reaction

Accompanying drawing 2, Fig. 3 show: in anaerobic ammonia oxidation activity stable stage (120d start), the average removal rate of ammonia nitrogen and nitrite nitrogen is as high as 94.79% and 98.17% respectively. It shows that obvious anaerobic ammonium oxidation phenomenon appeared in the bioreactor. It can be seen from Figure 4 that after entering the stable operation stage, from the 19th day to the 57th day, the ratio of nitrite nitrogen removal to ammonia nitrogen removal fluctuated between 2.77 and 7.67, and the average ratio was 4.17, which was larger than the 1.32 reported in the literature. For the increase, it shows that there is a strong denitrification reaction. From the 58th day to the 125th day, the ratio of nitrite nitrogen removal to ammonia nitrogen removal fluctuated between 1.17 and 3.28, and the average ratio was 2.03, which was still higher than the 1.32 reported in the literature, indicating that there was a certain denitrification reaction. From the 128th day to the 202nd day, the ratio of nitrite nitrogen removal to ammonia nitrogen removal fluctuated between 1.22 and 1.64, and the average ratio was 1.37, which was quite close to the 1.32 reported in the literature in the inorganic environment.

2. Denitrification and denitrification reaction

Figure 5 shows: During the test, the highest removal rate of COD can reach 51.68%, and the average removal rate of the whole reaction is only 26.28%. , in the stable stage of anammox activity, the average COD removal rate was 23.51%, and the corresponding average volume removal loads were 110.50mg/(L.d) and 84.53mg/(L.d). It shows that in the organic environment, the anammox reactor can successfully realize the anammox reaction and denitrification reaction at the same time, so that the excess nitrate nitrogen can be turned into nitrogen gas through denitrification, which not only completely removes nitrogen, but also A part of COD can be removed. It solves the international problems in this field and has important engineering application value.

Claims (2)

1, the method for a kind of percolate Anammox and denitrification synergistic denitrification is characterized in that earlier pending garbage, waste-water and contains nitre nitrogen water mixing, and pending waste water is become contain COD, NH ₄ ⁺, NO ₂ ^-Or NO ₃ ^-Organic waste water, organic waste water is entered introduce active sludge and percolate carries out the anaerobic mud bed of anaerobic ammonia oxidizing bacteria and denitrifying bacteria enrichment and domestication then, to the COD in the organic waste water, NH ₄ ⁺, NO ₂ ^-Or NO ₃ ^-By the synergy of anaerobic ammonia oxidizing bacteria and denitrifying bacteria, remove to take off COD, ammonia nitrogen and nitrite nitrogen synchronously, the temperature of anaerobic mud bed processing waste water is controlled to be 26～36 ℃.

2, the method for percolate Anammox according to claim 1 and denitrification synergistic denitrification is characterized in that the temperature of anaerobic mud bed processing waste water is controlled to be 30 ℃.

Images