阅读说明：本技术 一种实现含氮废水低温短程硝化的方法 (Method for realizing low-temperature short-cut nitrification of nitrogen-containing wastewater ) 是由 于莉芳 莫鹏程 李韧 惠晓飞 张兴秀 汪宇 彭党聪 于 2019-09-09 设计创作，主要内容包括：本发明公开了一种实现含氮废水低温短程硝化的方法,包括：在8～15℃下,采用活性污泥法处理含氮废水,当出水氨氮去除率达到90％以上、且亚硝酸盐积累率低于80％时,将浓缩活性污泥在35℃下加热处理后再用于废水处理。本方法利用AOB和NOB对不同环境温度的响应差异,仅对废水处理系统沉淀或者浓缩后的活性污泥进行短期加热处理,再回至废水处理系统,即可立即实现短程硝化；本方法仅对经沉淀或浓缩后的污泥进行加热处理,处理的污泥体积小,能耗相对较低。(The invention discloses a method for realizing low-temperature short-cut nitrification of nitrogenous wastewater, which comprises the following steps: treating the nitrogenous wastewater by an activated sludge method at 8-15 ℃, and heating the concentrated activated sludge at 35 ℃ for wastewater treatment when the removal rate of ammonia nitrogen in effluent reaches more than 90% and the accumulation rate of nitrite is lower than 80%. According to the method, the response difference of AOB and NOB to different environmental temperatures is utilized, only short-term heating treatment is carried out on the activated sludge precipitated or concentrated by the wastewater treatment system, and then the activated sludge is returned to the wastewater treatment system, so that short-range nitrification can be immediately realized; the method only carries out heating treatment on the precipitated or concentrated sludge, and the treated sludge has small volume and relatively low energy consumption.)

1. A method for realizing low-temperature short-cut nitrification of nitrogen-containing wastewater is characterized by comprising the following steps: treating the nitrogenous wastewater by an activated sludge method at 8-15 ℃, and heating the concentrated activated sludge at 35 ℃ for wastewater treatment when the removal rate of ammonia nitrogen in effluent reaches more than 90% and the accumulation rate of nitrite is lower than 80%.

2. The method for realizing the low-temperature short-cut nitrification of the nitrogen-containing wastewater as claimed in claim 1, which is characterized by comprising the following steps:

step 1, operating an activated sludge system;

sequentially carrying out five stages of water inlet, aeration, sedimentation, water outlet and standing on an activated sludge system at the temperature of 8-15 ℃, wherein each five stages form a period, the activated sludge system runs for 6 periods every day, and each period is 4 hours; controlling the sludge age to be 25-30 days, measuring the effluent quality every day, and performing the step 2 when the ammonia nitrogen removal rate of the effluent reaches more than 90% and the nitrite accumulation rate is lower than 80%;

step 2, heating and concentrating the activated sludge;

concentrating and cleaning sludge, removing a matrix, adjusting the heat treatment environment of the sludge to be 35 ℃ and the dissolved oxygen concentration to be 2-3 mg/L, maintaining the state for 2 days, centrifugally cleaning the heated sludge, and then performing the step 1; the above process is repeated.

3. The method for realizing the low-temperature short-cut nitrification of nitrogen-containing wastewater according to claim 2, wherein in the step 2, the activated sludge is subjected to a concentration treatment before being heated.

4. The method for realizing the low-temperature short-cut nitrification of nitrogen-containing wastewater as claimed in claim 2, wherein in each period, the water inlet time is 5min, the aeration time is 180min, the precipitation time is 40min, the water outlet time is 5min, and the standing time is 10 min.

Technical Field

The invention belongs to the technical field of sewage treatment, and particularly relates to a method for quickly realizing low-temperature short-cut nitrification of nitrogenous wastewater in a mode of intermittently heating and concentrating activated sludge.

Background

Nitrogen is one of important indexes for evaluating water quality, and excessive nitrogen in water body can deteriorate water quality and influence growth and propagation of aquatic organisms. At present, the biological denitrification of wastewater mainly adopts a traditional nitrification and denitrification process, the energy consumption required by aeration of the process is high, and the C/N of most of nitrogen-containing wastewater is low, so that the requirement of denitrification on a carbon source cannot be met, and the total nitrogen concentration of effluent exceeds the standard. In order to solve the problem, researchers develop novel biological denitrification processes such as short-cut nitrification and denitrification, Anammox and the like in sequence so as to save aeration cost and carbon source consumption.

However, the new biological denitrification process requires a large amount of NO₂ ^-Participate in the reaction as an electron acceptor. Short-cut nitrification is generally considered economically viable NO₂ ^-Provides a way. The short-cut nitrification technology controls the biological nitrification process at the ammonia oxidation stage, namely NH₄ ⁺Oxidation to NO₂ ^-Thereby providing an electron acceptor for the subsequent denitrification process, and the key point is that AOB (ammonia oxidizing bacteria) is enriched and NOB (nitrite oxidizing bacteria) is inhibited or eliminated simultaneously, and NO is prevented₂ ^-Continued oxidation to NO₃ ^-。

The current method for inhibiting or eliminating NOB is mainly based on the difference of the physiological characteristics of AOB and NOB, such as dissolved oxygen affinity (DO concentration control and aeration time control); tolerance of FA and FNA (FA and FNA inhibition), proliferation rate difference (high temperature and short sludge age), and the like. However, the methods for realizing short-cut nitrification create an environment for inhibiting the growth of NOB in a wastewater treatment system, and require a certain time to gradually eliminate the NOB, but the elimination processes may simultaneously inhibit AOB to a certain extent, and the NOB has strong physiological adaptability and population structure optimization adaptability to the environment, and after long-time operation, the NOB activity is restored again, so the elimination processes of the methods for NOB are unstable, especially under the condition of low water temperature in winter, the growth rate of the NOB is higher than that of the AOB, and short-cut nitrification failure is more easily caused, thereby limiting the application of the novel biological denitrification process under the low temperature condition.

Disclosure of Invention

Aiming at the defects and shortcomings of the prior art, the invention provides a method for realizing low-temperature short-cut nitrification of nitrogen-containing wastewater by utilizing the difference of inactivation critical temperatures of AOB and NOB enzymes, namely, the activity of NOB suitable for low-temperature growth is attenuated or inactivated by intermittently heating and concentrating activated sludge, while the activity of AOB is not influenced or even increased, so that the activity difference between AOB and NOB is enlarged, the low-temperature short-cut nitrification of nitrogen-containing wastewater is quickly realized, and the problem that the elimination process of NOB in the prior art is unstable is solved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for realizing low-temperature short-cut nitrification of nitrogen-containing wastewater comprises the following steps: treating the nitrogenous wastewater by an activated sludge method at 8-15 ℃, and heating the concentrated activated sludge at 35 ℃ for wastewater treatment when the removal rate of ammonia nitrogen in effluent reaches more than 90% and the accumulation rate of nitrite is lower than 80%.

Specifically, the method comprises the following steps:

step 1, operating an activated sludge system;

sequentially carrying out five stages of water inlet, aeration, sedimentation, water outlet and standing on an activated sludge system at the temperature of 8-15 ℃, wherein each five stages form a period, the activated sludge system runs for 6 periods every day, and each period is 4 hours; controlling the sludge age to be 25-30 days, measuring the effluent quality every day, and performing the step 2 when the ammonia nitrogen removal rate of the effluent reaches more than 90% and the nitrite accumulation rate is lower than 80%;

step 2, heating and concentrating the activated sludge;

concentrating and cleaning sludge, removing a matrix, adjusting the heat treatment environment of the sludge to be 35 ℃ and the dissolved oxygen concentration to be 2-3 mg/L, maintaining the state for 2 days, centrifugally cleaning the heated sludge, and then performing the step 1; the above process is repeated.

Specifically, in each period, the water inlet time is 5min, the aeration time is 180min, the precipitation time is 40min, the water outlet time is 5min, and the standing time is 10 min.

Compared with the prior art, the invention has the beneficial effects that:

(1) the processing method is simple, and the realization time is short: according to the method, the difference of AOB and NOB in response to different environmental temperatures is utilized, only short-term heating treatment is carried out on sludge precipitated or concentrated by a wastewater treatment system, and then the sludge is refluxed to the wastewater treatment system, so that short-range nitrification can be immediately realized.

(2) The economic cost is low: the method only carries out heating treatment on the sludge after precipitation or concentration, the treated sludge has small volume and relatively low energy consumption; any inhibiting substance is not required to be added in the treatment process, the original device and equipment are not required to be changed, only the sludge heating device is required to be added, and the installation and the disassembly are convenient.

(3) NOB inhibitory effect was stable: in the method, the activated sludge is alternately in two stages of high-temperature inhibition (activated sludge heating and concentrating stage) and low-temperature operation, the NOB activity of the activated sludge after heating treatment is obviously reduced at low temperature, and the AOB activity is not influenced or even increased, so that the activity difference between the AOB and the NOB is enlarged, and the low-temperature short-cut nitrification of the nitrogenous wastewater is quickly realized.

Drawings

FIG. 1 is a flow chart of the method of the present invention.

FIG. 2 is a test apparatus used in an embodiment of the present invention.

FIG. 3 shows the change of nitrification performance and nitrite accumulation rate before and after heating of activated sludge in the example of the present invention.

The meaning of the various reference numbers in the drawings: 1-SBR reactor, 2-constant temperature water bath system, 3-online pH and DO detection equipment, 4-stirring device, 5-aeration sand tray, 6-water inlet system, 7-water outlet system and 8-constant temperature water bath layer;

11-a water inlet system preformed hole, 12-a water outlet system preformed hole, 13-a DO probe preformed hole, 14-a pH probe preformed hole and 15-a sampling port;

21-a water bath water inlet pipe and 22-a water bath water outlet pipe;

31-DO probe, 32-pH probe, 33-host, 34-data line;

41-stirring motor, 42-stirring blade.

The invention is described in detail below with reference to the drawings and the detailed description.

Detailed Description

The activated sludge in the invention is taken from a sewage treatment plant.

The nitrite accumulation rate of less than 80% in the invention means that the ratio of nitrite concentration in the sum of nitrate and nitrite concentration is less than 20%.

The invention realizes stable short-cut nitrification by intermittently heating the concentrated activated sludge at low temperature. After the heating treatment, the NOB activity in the activated sludge is reduced, so that nitrite accumulation is caused, and short-cut nitrification is realized. However, the NOB gradually recovers activity due to the adaptability of the microorganisms to the environment, so that when the NOB activity recovers to a certain degree and the nitrite accumulation rate drops to a certain value (the nitrite accumulation rate is set to be lower than 80% by the method of the invention), the sludge is heated again (namely, the sludge is in a pause state), thereby realizing a stable shortcut nitrification effect.

The method for realizing the low-temperature short-cut nitrification of the nitrogenous wastewater specifically comprises the following steps:

step 1, operating an activated sludge system;

putting activated sludge into an SBR reactor, adjusting the water temperature inside the SBR reactor to be 8-15 ℃, sequentially carrying out five stages of water inlet, aeration, sedimentation, water outlet and standing, wherein each five stages form a period, the operation is carried out for 6 periods every day, and each period is 4 hours; controlling the sludge age to be 25-30 days, measuring the effluent quality (including ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and pH) every day, and performing the step 2 when the ammonia nitrogen removal rate of the effluent reaches more than 90% and the nitrite accumulation rate is lower than 80%;

in the present invention, sludge age can be controlled by removing activated sludge from the reactor every day.

Step 2, heating and concentrating the activated sludge;

concentrating and cleaning the sludge, removing a substrate, wherein the substrate generally refers to nitrogen, phosphorus, a carbon source and the like remained in the sludge, adjusting the heat treatment environment of the sludge to be 35 ℃ and the dissolved oxygen concentration to be 2-3 mg/L, maintaining the state for 2 days, centrifugally cleaning the heated sludge, and then performing the step 1. The above process is repeated.

In the method of the present invention, the activated sludge may be subjected to a thickening treatment before heating the activated sludge. Specifically, activated sludge is precipitated for a period of time, supernatant is discarded, the volume of sludge at the bottom is the volume of the concentrated sludge, the volume of the activated sludge is reduced after concentration, and energy consumption required by heating is reduced.

The following embodiments of the present invention are provided, and it should be noted that the present invention is not limited to the following embodiments, and all equivalent changes based on the technical solutions of the present invention are within the protection scope of the present invention.