CN108706731B - Process for realizing low-ammonia nitrogen shortcut nitrification-anaerobic ammonia oxidation - Google Patents

Abstract

The invention provides a process for realizing low ammonia nitrogen shortcut nitrification-anaerobic ammonia oxidation (PNAnammox). The process adopts the modified ammonium ion sieve as a filler, and is combined with the regulation and control of the operating parameters of the reactor to realize the long-term stable operation of PNAnammox. The invention utilizes the advantage that the modified ammonium ion sieve specifically adsorbs a large amount of ammonia nitrogen, simultaneously inhibits the metabolic activity of Nitrite Oxidizing Bacteria (NOB), continuously modifies the thickness of a microbial membrane by utilizing hydraulic shearing force, and continuously elutes the NOB which is not attached to the biological membrane and anammox and AOB which fall off and die from the biological membrane by utilizing SRT so as to realize the long-term stable and efficient denitrification effect.

Description

Process for realizing low-ammonia nitrogen shortcut nitrification-anaerobic ammonia oxidation

Technical Field

The invention relates to the field of low ammonia nitrogen wastewater treatment, in particular to a process for realizing the stable operation of shortcut nitrification-anaerobic ammonia oxidation by utilizing a functional carrier and controlling the stirring speed of a reactor and the retention time of sludge.

Background

As a representative of low ammonia nitrogen sewage, the production amount of town sewage is increased along with the continuous acceleration of urbanization. Ammonia nitrogen is used as a main inorganic pollutant in urban sewage, and although the concentration of the ammonia nitrogen is far lower than that of industrial wastewater, the ammonia nitrogen is still a great problem in urban sewage treatment. In the treatment process of ammonia nitrogen sewage, a microbial treatment method and a physical adsorption method are two more common technical methods.

Compared with the traditional nitrification and denitrification process, the short-cut nitrification-anaerobic ammonia oxidation (PNAnamox) technology serving as a novel biological denitrification process can save the treatment cost by 90 percent, has the great advantages of energy conservation, high efficiency and environmental friendliness, conforms to the idea of establishing a Chinese concept sewage treatment plant, and has wide application prospect. However, in town wastewater with low ammonia nitrogen concentration, the low free ammonia concentration is difficult to achieve the activity inhibition of Nitrite Oxidizing Bacteria (NOB), so that the establishment of short-cut nitrification is difficult, and the application of the PNAnammox technology in town sewage treatment is severely restricted.

The physical adsorption method realizes the optimization of water quality by adsorbing ammonia nitrogen through the adsorbent, but after the adsorbent reaches an adsorption saturation state, the ammonia nitrogen adsorption capacity of the adsorbent is reduced, so that the effluent water quality is deteriorated. And the continuous replacement of the adsorbent or the physical regeneration of the adsorbent can greatly increase the treatment cost, so that the ammonia nitrogen wastewater is treated by combining the adsorbent with a microbial regeneration method at present.

The ammonia nitrogen adsorbent has the advantage of specifically adsorbing a large amount of ammonia nitrogen, forms a high-free ammonia microenvironment by releasing a large amount of free ammonia, and inhibits the activity and growth of NOB, so that the stable operation of PNAnammox is realized under the condition of low ammonia nitrogen concentration. However, most of the currently used ammonia nitrogen adsorbents are natural materials, such as zeolite, montmorillonite and the like, and have limited adsorption capacity for ammonia nitrogen; when the adsorbents are used, a fixed bed membrane bioreactor is adopted, the mass transfer capacity is reduced due to the tight filling of the filler, the activity of Ammonia Oxidizing Bacteria (AOB) and anaerobic ammonia oxidizing bacteria (anammox) is reduced in the later period of operation, the performance of the reactor is deteriorated, and the long-term stable operation of PNanammox is difficult to realize.

Disclosure of Invention

The invention aims to provide a process for realizing low-ammonia nitrogen shortcut nitrification-anaerobic ammonia oxidation, which specifically comprises the steps of forming a biomembrane layered structure of anaerobic ammonia oxidation (anammox) and Ammonia Oxidizing Bacteria (AOB) by using a modified ammonium ion sieve, and realizing long-term stable operation of the shortcut nitrification-anaerobic ammonia oxidation (PNanammox) by combining regulation and control of the stirring speed of a reactor and the Sludge Retention Time (SRT).

Preferably, the raw material of the ammonium ion sieve is natural kaolin powder.

More preferably, the diameter of the natural kaolin powder is 20-30 μm.

Preferably, the modifier used for the synthetic ammonium ionic sieve is sodium chloride (NaCl).

Preferably, the mass ratio of the modifier NaCl to the kaolin powder is 1: 2-1: 1.

Further preferably, the mass ratio of all the modification systems is NaCl: kaolin: water is 1:2:3 to 1:1: 1.

Preferably, the drying temperature is 90-110 ℃.

Preferably, the pore former used is carbon black.

Further preferably, the mass ratio of the carbon black to the ammonium ion sieve is 1: 4-1: 3.

Further preferably, the roasting temperature is 400-500 ℃.

Preferably, the stirring speed is 80-120 r/min.

Preferably, the SRT is 5-10 days.

Preferably, the ammonia nitrogen concentration of the wastewater is 30-50 mg/L.

Further preferably, the ammonia nitrogen concentration of the wastewater is 45-50 mg/L.

Preferably, the method of the present invention comprises the steps of:

preparing an ammonium ion sieve with uniform pores, and controlling the stirring speed of a reactor and the sludge retention time; the ammonium ion sieve is generated by modifying natural kaolin powder, the diameter of the used kaolin powder is 20-30 mu m, the used modifier is NaCl, and the mass ratio of the used modification system is NaCl: kaolin: water is 1:2: 3-1: 1:1, and the drying temperature is 90-110 ℃; the pore-forming agent is carbon black, the mass ratio of the carbon black to the ammonium ion sieve is 1: 4-1: 3, and the roasting temperature is 400-500 ℃; the stirring speed is 80-120 r/min; the SRT is 7-10 days; the ammonia nitrogen concentration of the wastewater is 45-50 mg/L.

The method has the following beneficial effects:

1) the modified ammonium ion sieve that this application adopted, than other ammonia nitrogen adsorbents, ammonia nitrogen saturation adsorption capacity increases 5 ~ 10 times, and the free ammonia concentration of release is showing and is increasing, not only is enough to supply anammox and AOB's growth metabolism needs, and it is more obvious to NOB's metabolic inhibition simultaneously, very big reduction PNAnamox's the establishing time.

2) The powdery ammonium ion sieve that this application adopted adds to reactor inside back, can form suspension fluidized bed, compares fixed bed technology, has increased the effective area with microorganism contact, uses pore-forming agent to form even hole on the carrier surface simultaneously, has not only obviously increased the fixed microorganism volume on the functional carrier, is favorable to increasing the mass transfer effect of nutrition matrix moreover to promote the layering distribution of anammox and AOB in the biomembrane.

3) The reactor stirring rotational speed that this application adopted can make modified ammonium ionic sieve suspension, makes ammonium ionic sieve and microorganism can fully contact, reaches the effect of even biofilm formation. Meanwhile, the biological membrane formed by taking the ammonium ion sieve as the core can be continuously modified, so that the thickness of the biological membrane can be favorably controlled, the reduction of the bacterial activity of the biological membrane caused by poor mass transfer is prevented, and the thickness ratio of an anaerobic layer inside the biological membrane to an aerobic layer outside the biological membrane can be favorably regulated and controlled, so that the abundance ratio of anammox to AOB is controlled, and the long-term stable operation of PNAnammox is realized.

4) The sludge retention time that this application adopted combines nitrifying mud and anaerobic ammonium oxidation sludge age to set for, not only can constantly elute the NOB who does not adhere to functional carrier to promote the steady operation of short-cut nitrification, can constantly eliminate the dead microbial cell of ageing moreover, keep the high denitrogenation efficiency in the reactor.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

Example 1

The embodiment relates to a process for preparing an ammonium ion sieve by using natural kaolin powder and modifying the ammonium ion sieve, which comprises the following steps:

1) grinding natural kaolin raw soil to reduce the particle size;

2) washing kaolin raw soil by using distilled water, and precipitating to remove impurities;

3) putting the cleaned kaolin into a drying table, and naturally drying;

4) screening by using 500-mesh and 700-mesh sieves in sequence, and screening kaolin with the particle size of 20-30 mu m;

5) according to the weight ratio of sodium chloride: kaolin: preparing a modified system by using water in a mass ratio of 1:2: 3-1: 1:1, and placing the modified system in 5000mL

Measuring cylinder, and stirring to obtain paste;

6) placing the measuring cylinder containing the modified system in a muffle furnace for drying, setting the temperature to be 90-110 ℃,

drying to constant weight;

7) soaking the modified system in excessive distilled water to remove sodium chloride not bonded to kaolin

A crystal;

8) after soaking for 5 hours, placing the mixture on a drying table, and naturally drying the mixture to form an ammonium ion sieve;

9) according to the carbon black: preparing a pore-forming system by using an ammonium ion sieve in a mass ratio of 1: 4-1: 3, placing the pore-forming system in a 5000mL measuring cylinder,

and mixing uniformly;

10) placing the measuring cylinder containing the pore-forming system in a muffle furnace for pore-forming to form the surface of the ammonium ion sieve

Uniform gaps are formed, the setting temperature is 400-500 ℃, and roasting is carried out for 2 hours;

11) soaking the pore-formed system in excessive distilled water, and cleaning the final product for 3 times;

12) and (4) after cleaning, placing the modified ammonium ion sieve on a drying table, and naturally airing for later use.

Example 2

The embodiment relates to a comparison of ammonia nitrogen saturation adsorption capacity of natural kaolin powder and a modified ammonium ion sieve at different temperatures, which comprises the following steps:

respectively adding 1g of natural kaolin powder and a modified ammonium ion sieve into 1L of solution with the ammonia nitrogen concentration of 300mg/L, respectively measuring isothermal adsorption curves of two ammonia nitrogen adsorbents at 20 ℃, 30 ℃ and 40 ℃, and finally calculating to obtain the adsorption saturation amount of the ammonia nitrogen, wherein the table is as follows:

adsorption experiments show that the saturated adsorption capacity of the modified ammonium ion sieve to ammonia nitrogen is remarkably increased and is 5.95-10.87 times of the saturated adsorption capacity of natural kaolin powder as a raw material to ammonia nitrogen, and the ammonia absorption capacity of the modified ammonium ion sieve is fully demonstrated.

Example 3

The embodiment relates to a method for comparing the treatment effects of low ammonia nitrogen wastewater by using natural kaolin powder and a modified ammonium ion sieve as carriers, simultaneously adjusting the stirring time of a reactor and the sludge retention time and utilizing a shortcut nitrification-anaerobic ammonia oxidation process, and the method comprises the following steps:

the natural kaolin powder and the modified ammonium ion sieve prepared in example 1 were respectively put into two 5L sequencing batch reactors, and the anammox sludge and the nitrified sludge were inoculated in this order. Adjusting the stirring speed of the reactor to 80-120 rpm, and adjusting the sludge retention time of the reactor to 5-10 days so as to achieve the effects of modifying the biological membrane and eliminating nitrite nitrogen oxide sludge and aged sludge. The ammonia nitrogen concentration of the inlet water is kept at 50mg/L by using the artificially prepared wastewater, the continuous operation is carried out for 30 days, and the ammonia nitrogen, nitrite nitrogen and nitrate nitrogen concentration of the inlet water and the outlet water of each period of the two reactors are detected. The nitrogen concentrations in the effluent from both reactors at day 30 are as follows:

through reactor experiments, the water quality of reactor effluent is better than that of reactor effluent using natural kaolin powder as a carrier under the condition that a modified ammonium ion sieve is used as the carrier and the stirring speed of the reactor and the sludge retention time are adjusted simultaneously. And the ammonia oxygen removal rate is 96.4 percent, the total nitrogen removal rate is 89.4 percent, and the emission standard meets the first-grade A emission standard of pollutant emission Standard (GB18918-2016) of urban wastewater treatment plants.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims (2)

1. A process for realizing low ammonia nitrogen shortcut nitrification-anaerobic ammonia oxidation is characterized in that a functional carrier is utilized to specifically form a layered biomembrane of anaerobic ammonia oxidation bacteria amammox and ammonia oxidation bacteria AOB, and the long-term stable operation of the shortcut nitrification-anaerobic ammonia oxidation PNanammox under the condition of low ammonia nitrogen concentration is realized by combining the regulation and control of the stirring speed of a reactor and the sludge retention time SRT; the initial content of ammonia nitrogen in the wastewater is 30-50 mg/L; the functional carrier is an ammonium ionic sieve carrier modified by kaolin powder, the ammonium ionic sieve carrier is prepared by preparing an ammonium ionic sieve by using natural kaolin powder and modifying the ammonium ionic sieve, and the method specifically comprises the following steps:

1) grinding natural kaolin raw soil to reduce the particle size;

2) washing kaolin raw soil by using distilled water, and precipitating to remove impurities;

3) putting the cleaned kaolin into a drying table, and naturally drying;

4) screening by using 500-mesh and 700-mesh sieves in sequence, and screening kaolin with the particle size of 20-30 mu m;

5) according to the weight ratio of sodium chloride: kaolin: preparing a modification system by using water in a mass ratio of 1:2: 3-1: 1:1, placing the modification system in a 5000mL measuring cylinder, and uniformly stirring to obtain paste;

6) placing the measuring cylinder containing the modified system in a muffle furnace for drying, setting the temperature to be 90-110 ℃, and drying to constant weight;

7) soaking the modified system in excessive distilled water to remove sodium chloride crystals which are not combined with kaolin;

8) after soaking for 5 hours, placing the mixture on a drying table, and naturally drying the mixture to form an ammonium ion sieve;

9) according to the carbon black: preparing a pore-forming system by using an ammonium ion sieve in a mass ratio of 1: 4-1: 3, placing the pore-forming system in a 5000mL measuring cylinder, and uniformly mixing;

10) placing the measuring cylinder containing the pore-forming system in a muffle furnace for pore forming to enable uniform gaps to be formed on the surface of the ammonium ion sieve, setting the temperature to be 400-500 ℃, and roasting for 2 hours;

11) soaking the pore-formed system in excessive distilled water, and cleaning the final product for 3 times;

12) and (4) after cleaning, placing the modified ammonium ion sieve on a drying table, and naturally airing for later use.

2. The process of claim 1 wherein the pore former is carbon black; the stirring speed is 80-120 rpm; the SRT is 5-10 days.