CN108033555A - A kind of method of the quick anaerobic biological treatment for starting garbage burning factory Leachate site - Google Patents

Abstract

The present invention proposes a method for quick start-up treatment of the leachate anaerobic biological treatment system of waste incineration plant containing extremely high COD concentration (50,000-70,000mg/L), the specific steps are: (1) inoculation of upflow anaerobic For anaerobic sludge with a volume ratio of 40% in the sludge bed reactor (UASB), 75g/L of conductive functional material (specially modified granular activated carbon) is added to the system, and the leachate raw solution directly enters the UASB reactor; (2) By adjusting the hydraulic retention time (HRT) and controlling the organic load of the treatment system, the rapid start-up and stable operation of the leachate biological treatment system can be realized. The conductive functional material added in the present invention promotes the efficient degradation of organic matter by strengthening the electron transfer process between microorganisms in the system, and reduces the impact load and high-concentration intermediate metabolites (such as propionic acid) on the treatment system during startup. The direct treatment of the leachate raw liquid is realized, and the start-up time of the UASB reactor is greatly shortened, the stability and treatment efficiency of the reaction system are improved, the methane production is increased, and the energy recovery rate is improved.

Description

A method for quickly starting an anaerobic biological treatment system for leachate in a waste incineration plant

technical field

The invention provides a method for rapidly starting and efficiently degrading an anaerobic biological treatment system for leachate (with a COD concentration as high as 50,000-70,000 mg/L) of a waste incineration plant. Mainly through the conductive functional materials, the electron transfer process between microorganisms in the system is strengthened, the degradation of organic matter is accelerated, and the purpose of directly and rapidly starting the anaerobic biological treatment system from the leachate raw solution is realized. The method is mainly applicable to the field of biological treatment of high-concentration organic wastewater.

Background technique

With the rapid development of cities and the improvement of people's living standards, a large amount of urban domestic waste is produced. As an effective means of waste reduction, harmlessness and resource utilization, waste incineration has been more and more widely used in recent years. Kitchen waste accounts for a large proportion of urban domestic waste in my country and has a high water content. It generally needs to be stored in pits for 3-7 days before incineration. This process will generate a large amount of leachate, which needs to be treated intensively. Compared with landfill leachate, fresh leachate produced by incineration plant has extremely high COD concentration (50,000-70,000mg/L), good biodegradability (BOD/COD>0.4), easy biodegradable volatile high fatty acid content.

Patent CN102153233A reports a leachate treatment method and system of a waste incineration plant. The method combines coagulation sedimentation, UASB+A/O process, MBR process, electrochemical reactor process and reverse osmosis membrane treatment process, and the treatment system that realizes the above method can discharge the treated landfill leachate up to the standard.

Patent CN105417843A reports a treatment method for zero discharge of leachate from municipal solid waste incineration plants. The method includes a combination process of grille-hydrolytic acidification tank-anaerobic reactor-anaerobic sedimentation tank-anoxic tank-aerobic tank-ultrafiltration membrane-nanofiltration-reverse osmosis, and the effluent reaches the national reuse water standard.

Patent CN106145351A reports a treatment equipment for leachate in a waste incineration power plant. The treatment equipment makes leachate homogeneous and equal, anaerobic digestion, primary biochemical treatment, nitrification precipitation, denitrification adjustment, secondary biochemical treatment and denitrification precipitation, and efficient removal of organic matter in leachate to achieve high efficiency. denitrification.

The leachate treatment methods of waste incineration plants described in the above three publicly reported patents all adopt a combined process method such as "physical chemistry + anaerobic digestion + aerobic denitrification + membrane formation advanced treatment". Anaerobic digestion, as the main process for greatly reducing the concentration of organic matter, has the advantages of small process investment, low consumption, and low operating costs, and has been widely used. However, in the actual treatment process, in order to achieve the treatment of extremely high concentration leachate raw solution, it usually takes a long time for sludge acclimatization. During the start-up process of the anaerobic bioreactor, the degradation of high-concentration organic matter by microorganisms can easily lead to a large accumulation of intermediate metabolites such as propionic acid, making the treatment system unstable or even acidified and collapsed. At the same time, in actual engineering, the anaerobic treatment unit of waste incineration leachate requires a large amount of backflow water to dilute the influent water, which greatly increases the treatment cost.

Patent CN102910732A reports a method for quickly starting an anaerobic reactor with high-concentration organic wastewater. By pretreating the inoculated sludge, the concentration of organic matter in the influent is gradually increased from 20% of the design value to the designed influent concentration value, and the sludge is inoculated again, and the hydraulic retention time is gradually reduced to the design value in stages, and the reactor is successfully started. Currently, the application For organic wastewater with a COD concentration of around 10,000mg/L. In this method, the concentration of organic matter is low at the beginning of the start-up process. For the leachate of waste incineration plants with extremely high COD concentration, the influent water needs to be diluted with a large amount of reflux water, which greatly increases the start-up cost. At the same time, inoculation of sludge twice increases the difficulty of actual engineering operation.

Patent CN105731640A reports a magnetite-enhanced bio-electrode coupled UASB device and its operating method. The method accelerates the start-up of the reactor by adding nano-magnetite into the bioelectrochemical anaerobic reactor, and is applied to simulated wastewater with a COD concentration of about 5000 mg/L. It is not reported whether this method can treat complex wastewater with extremely high COD concentration. If this method is used to treat leachate raw liquid of waste incineration plant with extremely high COD concentration, the operation difficulty and cost will be greatly increased due to the high energy consumption of the bioelectrode.

Patent CN107043160A reports a two-phase anaerobic treatment device and process based on magnetite and activated carbon reinforcement, which can be applied to the upgrade of the existing two-phase anaerobic process to resist the impact of high organic load wastewater. Although this method can improve the efficiency of hydrolysis and acidification under high organic loading, the COD concentration of the influent is only about 6000-10,000mg/L, which is not suitable for the leachate of waste incineration plants with extremely high COD concentration.

Patent CN106830308A introduces a method of using ethanol and biochar to accelerate the decomposition of anaerobic propionic acid and butyric acid, which is applied to wastewater containing propionic acid or butyric acid with a COD concentration of about 5,000mg/L, and is not suitable for extremely high COD concentrations Leachate from waste incineration plants.

At present, there is no patent report on the rapid start-up method for the anaerobic biological treatment system of waste incineration leachate with extremely high COD concentration and containing various complex components in China. Therefore, the present invention proposes a method for quickly starting an anaerobic bioreactor by directly leaching stock solution by adding modified granular activated carbon as a conductive functional material. Conductive functional materials can enrich a variety of bacteria with extracellular electron transfer function. These bacteria can conduct electron transfer through conductive materials, and transfer electrons to methanogens that can directly accept electrons to reduce carbon dioxide to produce methane, thereby accelerating the degradation of organic matter. , strengthen the methane yield, realize the purpose of directly starting the anaerobic reactor with the leachate raw liquid of the waste incineration plant, and greatly shorten the start-up time.

Contents of the invention

The purpose of the present invention is to provide an anaerobic bioreactor which realizes rapid start-up of direct waste incineration leachate stock solution by adding conductive functional materials. The method can greatly shorten the start-up time, improve the treatment effect, save a large amount of reflux dilution water, and reduce the start-up cost of the anaerobic biological treatment system.

In the method, the anaerobic bioreactor that adopts comprises: waste incineration leachate stoste water tank (1), water pump (2), anaerobic reactor water inlet (3), anaerobic reactor mud discharge hole (4 ), anaerobic reactor heating belt (5), temperature probe (6), three-phase separator (7), anaerobic reactor air outlet (8), anaerobic reactor water outlet (9), temperature control (10 )

In the method, the conductive functional material is added to the anaerobic sludge and fully mixed.

In the method, the conductive functional material is subjected to ultrasonic pretreatment to remove impurities on the surface.

In the method, the concentration of the conductive functional material added into the anaerobic bioreactor is 75-100g/L.

In the method, the processed waste incineration leachate stock solution has the obvious characteristics of extremely high COD concentration (50,000-70,000 mg/L) and high ammonia nitrogen concentration, and belongs to the category of high-concentration organic wastewater;

The purpose of the present invention is specifically achieved through the following technical solutions:

Sludge pretreatment: Take anaerobic sludge with a volume ratio of 30-50% and a conductive functional material with a concentration of 75-100g/L, fully mix and add to the anaerobic bioreactor.

The waste incineration leachate raw liquid is used as influent water (COD concentration 50,000-70,000mg/L), which is introduced into the anaerobic bioreactor through a water pump, and the operating temperature in the reactor is controlled at 30-35°C.

Adjust the initial HRT at 8-12d (the organic load is around 6kgCOD/(m ³ ·d)), measure the indicators such as COD removal rate, methane production rate and effluent VFAs concentration, and gradually shorten the HRT to the project after the reactor runs stably Required organic load.

Technical principle: The conductive functional material added to the anaerobic sludge can enrich the functional bacteria with extracellular electron transfer and archaea that can directly accept electrons to reduce carbon dioxide to produce methane on its surface, thereby strengthening the direct electron exchange between microorganisms Transfer ability, so as to increase the rate of methane production, promote the efficient degradation of organic matter, reduce the impact of the shock load and the extremely high organic concentration on the system during the start-up process, achieve the purpose of direct stock solution start-up, and greatly shorten the start-up time of anaerobic bioreactors.

Description of drawings

Fig. 1 is a schematic diagram of anaerobic biological treatment reactor of the present invention

Fig. 2 is the processing effect diagram adopting the present invention to start anaerobic bioreactor

Detailed ways

In the specific implementation, the influent water comes from the leachate stock solution produced by a waste incineration treatment plant in Beijing, and its water quality indicators are as follows: COD about 55,000mg/L, BOD about 20,000mg/L, NH ₄ ⁺ -N about 820mg/L, TN 1100mg/L or so. Simultaneously start two sets of UASB reactors.

Take unacclimated anaerobic sludge whose inoculum volume accounts for 40% of the volume ratio of the reactor, add 75g/L conductive functional material to the experimental group, mix well, and add it to the anaerobic bioreactor, and directly add any material to the blank group In the anaerobic bioreactor, the sludge concentration of both groups was 0.66VSS/L. Directly use undiluted waste incineration leachate stock solution as influent, HRT is set to 9.3 days, organic load is 5.9kgCOD/(m ³ ·d), and temperature is 33°C. Under this condition, the COD removal rate of the blank group continued to drop below 50%, and the anaerobic reactor failed to start (as shown in Figure 2). While the experimental group has been running for 60 days, the COD removal rate has gradually increased from 75% to 95%, and it can run stably. Further shorten the HRT to 4.6 days, increase the organic load to 12.0kgCOD/(m ³ ·d), operate under this condition for 15 days, the COD removal rate gradually rises from 74% to 95%, and can run stably. At this time, the anaerobic The reactor start-up is complete.

In order to further improve the treatment efficiency of the anaerobic bioreactor, the HRT was gradually shortened to 2.2 days, and the organic load was increased to 25kgCOD/(m ³ ·d). Under these conditions, the COD removal rate was always stable at about 90%.

Claims (6)

1. the present invention proposes one kind by adding conducting function material, the quick anaerobic organism for starting garbage burning factory Leachate site The method of processing system, the anaerobic reactor include：Garbage burning factory Leachate site water tank inlet (1), water pump (2), anaerobism Reactor water inlet (3), anaerobic reactor take mud hole (4), anaerobic reactor heating tape (5), temp probe (6), three separation Device (7), anaerobic reactor venthole (8), anaerobic reactor water outlet (9), temperature control (10).

A kind of 2. side of quick anaerobic biological treatment for starting garbage burning factory Leachate site according to claim 1 Method, it is characterised in that conducting function material is added in anaerobic sludge.

A kind of 3. side of quick anaerobic biological treatment for starting garbage burning factory Leachate site according to claim 1 Method, it is characterised in that handled Leachate site has the obvious water quality characteristics of high COD and ammonia nitrogen concentration, and it is organic to belong to high concentration Waste water category.

A kind of 4. side of quick anaerobic biological treatment for starting garbage burning factory Leachate site according to claim 1 Method, it is characterised in that be directly realized by and ooze drip stoste startup anaerobic biological treatment, greatly save reflux dilution water, reduce Start-up cost.

A kind of 5. side of quick anaerobic biological treatment for starting garbage burning factory Leachate site according to claim 1 Method, mainly includes the following steps that：

1) before reactor seed sludge, conducting function material is added into anaerobic sludge, is stirred and evenly mixed；The conducting function material Expect for modified granular activated carbon, in black, particle diameter be 20-30 mesh, specific surface area be about 1000m³/ g, electrical conductivity are about 26 μ S/cm, the dosage in reactor are 75g/L；

2) inoculation step 1 in anaerobic biological reactor) obtained mixing sludge, reactor volume is accounted for than 40%, oozes drip stoste It is directly entered reactor；

3) initial HRT is set at 10 days or so, organic loading 6kgCOD/ (m³D) left and right.Gradient shortens HRT, is lifted organic negative Lotus is to setting value.Temperature control is at 35 DEG C or so.

A kind of 6. side of quick anaerobic biological treatment for starting garbage burning factory Leachate site according to claim 1 Method, by adding conducting function material, the electron transfer process in fortification system between microorganism, improves efficiently using for electronics Rate, promotes the efficient degradation of organic matter, reduces system is subject in start-up course impact load and high concentration mesostate The influence of (such as propionic acid), achievees the purpose that shortening anaerobic biological reactor starts the time, meanwhile, this method can increase the production of methane Raw amount, improves anaerobic bio-treated efficiency, cost-effective.