Method for preparing carbon source by using waste rice and application thereof

Abstract

The application discloses a method for preparing carbon source by using waste rice and application thereof, and comprises the following steps: after the waste rice is cleaned and dried, the dried waste rice is added into a fermentation tank, anaerobic sludge is added into the fermentation tank, a mixed solution is obtained, nitrogen is continuously introduced into the fermentation tank, an anaerobic environment is maintained in the fermentation tank, and fermented waste rice is obtained after the process is completed; treated sewage is flowed into a carbon source tank body from a water inlet end, the fermented waste rice in the carbon source tank body is eluted, the fermented waste rice releases carbon source, and the carbon source is flowed out from a water outlet end and then enters a sewage treatment facility. The application solves the problem of resource utilization of the waste rice, has high utilization efficiency of the waste rice, has good economic value, and conforms to the principles of circular economy and sustainable development; the cost of preparation of the carbon source is reduced, and the effect of denitrification and phosphorus removal of the sewage is enhanced. Compared with the currently popular preparation of carbon source by using kitchen waste, the application reduces pretreatment measures such as oil removal and crushing and squeezing, and is more convenient and fast.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing carbon source from waste rice and application thereof, and belongs to the technical field of resource recycling. BACKGROUND

[0002] Activated sludge method and biofilm method are commonly used biological treatment methods, both of which rely on microbial metabolic activity to remove pollutants, but insufficient carbon source will reduce the activity of microorganisms, thereby reducing the removal effect of nitrogen and phosphorus pollutants. In order to improve the biodegradability of wastewater, sodium acetate, methanol and glucose and other additional carbon sources are usually added, which can provide quickly utilized organic matter, improve the metabolic activity of microorganisms, and enhance the effect of wastewater treatment. However, the cost of additional carbon source is high, which limits its wide application. In order to solve the problem of insufficient carbon source, it is particularly important to explore an economic and efficient carbon source supplement method. Waste resource technology converts organic waste into available carbon source through anaerobic fermentation, which becomes a solution with significant environmental and economic benefits. Organic waste such as food waste and waste crops is rich in organic matter, and can produce acetic acid, methanol and other carbon sources that can be easily utilized by microorganisms through anaerobic fermentation. This method not only reduces the operation cost of wastewater treatment, but also realizes the recycling of resources, which has important environmental and economic significance.

[0003] China produces a large amount of waste rice every year, mainly including unqualified rice (pollutants exceeding standard, unqualified moisture content, etc.), expired rice (stored for too long) and processing loss rice (broken rice, inferior rice, etc.). Although the resource utilization of waste rice is various at present, such as feed processing, industrial recycling and organic fertilizer, etc., these recycling methods do not fully realize the potential value of waste rice, and there are problems such as imperfect treatment technology, low utilization efficiency and low economic benefit. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a method for preparing carbon source from waste rice and application thereof, which has high utilization efficiency and good economic benefit.

[0005] In order to achieve the above purpose, the present application adopts a method for preparing carbon source from waste rice, which comprises the following steps:

[0006] S1, pretreatment: after washing and drying the waste rice, the dried waste rice is added to the fermentation tank, anaerobic sludge is added to the fermentation tank, nitrogen gas is continuously introduced into the fermentation tank to maintain anaerobic environment in the fermentation tank, and the fermented waste rice is obtained after the end, which is washed and reserved;

[0007] S2, a carbon source tank is used to prepare the carbon source: the carbon source tank comprises a cylindrical and hollow carbon source tank body, one end of the carbon source tank body is a water inlet end, the other end is a water outlet end, a vertical elution tank is detachably installed in the carbon source tank body, the side wall of the elution tank is mesh-shaped, the bottom of the elution tank is filled with ceramsite, and the anaerobic sludge and the cleaned fermented waste rice obtained in step S1 are placed above the ceramsite; the sewage to be treated flows into the carbon source tank from the water inlet end and elutes the fermented waste rice in the elution tank, so that the fermented waste rice releases the carbon source and flows out from the water outlet end into the sewage treatment facility.

[0008] As an improvement, at least one of unqualified rice, expired rice and processing loss rice is used as the waste rice in step S1.

[0009] The waste rice is cleaned with clean water and then is placed under sunlight to dry the surface.

[0010] As an improvement, the mass ratio of the waste rice to the anaerobic sludge added into the fermentation tank in step S1 is (0.2-0.3):1.

[0011] As an improvement, the fermentation tank in step S1 is provided with a stirring device, the fermentation temperature is 30-50℃, and the fermentation time is 3-5d.

[0012] As an improvement, the filling volume of the ceramsite in step S2 accounts for 1 / 3 of the volume of the elution tank, the bottom area of the elution tank accounts for 1 / 9 of the bottom area of the carbon source tank, the elution tank is made of stainless steel, and a plurality of mesh holes are formed in the side wall of the elution tank.

[0013] As an improvement, a plurality of water inlets are arranged at the water inlet end, and a plurality of water outlets are arranged at the water outlet end, and the water inlets and the water outlets each account for 1 / 16 of the bottom area of the elution tank.

[0014] As an improvement, the mass ratio of the fermented waste rice to the anaerobic sludge in the elution tank in step S2 is (0.2-0.3):1.

[0015] In addition, the application also provides an application of the carbon source prepared by the method in sewage treatment.

[0016] As an improvement, the method comprises the following steps:

[0017] Water quality information of the water inlet and the water outlet of the sewage area to be treated is obtained, and the amount of additional carbon source required for the effluent to stably meet the standard is determined;

[0018] According to the required amount of additional carbon source, the amount of fermented waste rice and anaerobic sludge in the elution tank is adjusted;

[0019] The assembled carbon source tank is placed in sewage, and the carbon source tank is rinsed in situ with sewage. The degradation rate of fermented waste rice is calculated, and the rinsing tank is cleaned and the fermented waste rice is replaced regularly.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This method solves the problem of resource utilization of waste rice, achieving high utilization efficiency and good economic value, and conforms to the principles of circular economy and sustainable development.

[0022] This reduces the cost of carbon source preparation and enhances the nitrogen and phosphorus removal efficiency of wastewater. Furthermore, compared to the currently popular method of using food waste to prepare carbon sources, it reduces pretreatment measures such as grease removal and crushing / pressing, making it more convenient and faster.

[0023] By adopting a rinsing mode and combining it with actual wastewater to prepare carbon sources, the process is simpler and more convenient. On the other hand, it only requires periodic replacement of fermented waste rice, reducing maintenance difficulty. At the same time, the water outlet on the carbon source tank avoids situations such as prolonged soaking of waste rice and excessive release of carbon sources. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the carbon source container of the present invention;

[0025] Figure 2 This is a diagram illustrating the carbon source release effect in an embodiment of the present invention.

[0026] In the diagram: 1. Carbon source tank, 2. Water inlet, 3. Water inlet, 4. Rinse tank, 5. Ceramsite, 6. Water outlet, 7. Water outlet. Detailed Implementation

[0027] The following embodiments are further illustrations of the present invention and serve as explanations of the technical content of the present invention. However, the essence of the present invention is not limited to the embodiments described below. Those skilled in the art can and should know that any simple changes or substitutions based on the spirit of the present invention should fall within the protection scope claimed by the present invention.

[0028] A method for preparing a carbon source using waste rice includes the following steps:

[0029] S1. Pretreatment: After washing and drying the waste rice, add the dried waste rice to a fermentation tank equipped with a stirring device. The fermentation temperature is 30-50℃. Then, add anaerobic sludge to the fermentation tank. The mass ratio of waste rice to anaerobic sludge is (0.2-0.3):1 to obtain a mixed liquid. Continue to introduce nitrogen gas into the fermentation tank to maintain an anaerobic environment. After fermentation for 3-5 days, fermented waste rice is obtained, which is then washed and used for later use.

[0030] Wherein, the waste rice adopts at least one of unqualified rice, expired rice, processing loss rice; the waste rice is washed with clean water, and after washing, is placed under sunlight to dry the surface;

[0031] The anaerobic sludge is used as inoculated sludge to start or optimize the microbial population of the biological reactor in the wastewater treatment process, and by adding the anaerobic sludge into the biological treatment system, an effective microbial ecosystem can be quickly established to help accelerate the purification process of the wastewater; in the sewage treatment plant, the anaerobic sludge contains various microorganisms (such as methanogens, acid-producing bacteria, etc.), which can decompose organic matter in the kitchen waste, and COD (carbon source) will increase with the decomposition of organic matter; the anaerobic sludge is generally obtained in the sewage treatment plant;

[0032] S2, carbon source is prepared by using a carbon source tank; as shown in the figure, Figure 1 The carbon source tank includes a cylindrical and hollow carbon source tank body 1, one end of the carbon source tank body 1 is a water inlet end 2, and the other end is a water outlet end 6, the water inlet end 2 is provided with a plurality of water inlets 3, and the water outlet end 6 is provided with a plurality of water outlets 7, and a vertical placed leaching tank 4 is detachably installed in the carbon source tank body 1, and the water inlet 3 and the water outlet 7 each account for 1 / 16 of the bottom area of the leaching tank 4;

[0033] The leaching tank 4 is made of stainless steel, a plurality of mesh holes (the aperture needs to allow water flow to pass normally, but the ceramic particles and rice particles cannot pass) are opened on the side wall, the bottom area of the leaching tank 4 accounts for 1 / 9 of the bottom area of the carbon source tank, and the bottom of the leaching tank 4 is filled with ceramic particles 5, and the filling volume of the ceramic particles 5 accounts for 1 / 3 of the volume of the leaching tank 4, and anaerobic sludge and the fermented waste rice obtained in step S1 are placed above the ceramic particles 5, and the mass ratio of the fermented waste rice and the anaerobic sludge is (0.2-0.3):1;

[0034] The treated wastewater flows into the carbon source tank body 1 from the water inlet end 2 and leaches the fermented waste rice in the leaching tank 4, so that the fermented waste rice releases carbon source and flows out from the water outlet end 6 and then enters the wastewater treatment facility.

[0035] The present application uses waste rice to prepare carbon source, which realizes the replacement of raw materials, and the main way of waste rice at present is used for feed or fertilizer processing, and the resource reuse efficiency is low, and the waste rice is used to prepare carbon source, which has an advantage in price compared with conventional industrial carbon source;

[0036] Compared with kitchen waste, the preparation of carbon source from discarded rice has two advantages: ① simple processing approach: no additional pre-treatment such as oil removal and crushing is needed (oil has a greater impact on biochemical reactions); ② high stability: the composition of kitchen waste changes greatly every day, resulting in changes in the concentration of the produced carbon source, while discarded rice is controllable and releases carbon source regularly and stably;

[0037] The third aspect is the process. Currently, the preparation of carbon source from kitchen waste is anaerobic fermentation (anaerobic tank is needed to be set, kitchen waste and anaerobic sludge are added, and stirring is performed), and the fermentation liquid is taken after a fixed time to supplement kitchen waste (high COD concentration and small water volume are produced). In the present application, discarded rice is preliminarily fermented, and then washed with water flow (low COD concentration and large water volume can be produced), compared with the anaerobic fermentation for preparing carbon source from kitchen waste, the washing does not need to adjust pH (less N source is brought in); rice degrades slowly and can release carbon source for a long time; there is no need to worry about the problem of long-term soaking of discarded rice due to power failure or blockage at the water outlet, resulting in the release of a large amount of carbon source (the problem is solved by setting the overflow port); the steps are simple, and only the fermented discarded rice needs to be replaced regularly. Example 1

[0038] An application of a carbon source prepared from discarded rice in wastewater treatment, comprising the following steps:

[0039] (1) Sampling in batches and at multiple locations in the wastewater area to be treated, including water inflow, water outflow and daily water inflow, mainly analyzing water quality indicators such as COD and nitrate nitrogen, recording the changes of COD concentration of water inflow and outflow and the changes of nitrate nitrogen of water outflow;

[0040] (2) According to the data obtained above, the COD concentration required to completely remove the nitrate nitrogen of the water outflow of the wastewater area to be treated is calculated, and the daily water inflow and average flow rate data of the treated area are recorded;

[0041] (3) Rice carbon source release experiment is carried out, the actual discarded rice dosage suitable for the wastewater area to be treated is obtained by simulating the actual water inflow flow rate and carrying out leaching experiment in batches;

[0042] (4) Installing a carbon source tank in the wastewater area to be treated, specifically including:

[0043]

[0044] The specific size of the carbon source tank is determined according to the actual situation of the wastewater to be treated. The anaerobic sludge and the fermented waste rice are added to the ceramic layer in the leaching tank 4, and the mass ratio of the fermented waste rice and the anaerobic sludge is 0.25:1. Then the wastewater from the water inlet end 2 enters the leaching tank 4, and the fermented waste rice is leached to release carbon source. The carbon source flows into the wastewater treatment facility from the water outlet end 6 by gravity, providing sufficient carbon source for denitrification of the wastewater treatment facility.

[0045] As the wastewater continuously leaches the fermented waste rice, the rice gradually rots and changes from solid to liquid and is discharged with the water flow. Then according to the foregoing experiments, the specific rotting time of the fermented waste rice is obtained. The leaching tank 4 is taken out regularly for cleaning and re-filling with pretreated fermented waste rice to prepare carbon source. Example 2

[0046] The waste rice is selected as the near-expiration Northeast Pearl Rice. The anaerobic sludge is obtained from the Zhuzhuangjing Wastewater Treatment Plant in Hefei, and the mixed liquid suspended solids (MLSS) concentration is 8.4 g / L, and the mixed liquid volatile suspended solids (MLVSS) is 5.6 g / L.

[0047] Step one, take 100g of near-expiration rice and wash it three times in a 1000ml measuring cup. After draining the water, place it in the sun for 3 hours.

[0048] Step two, add the dried rice to a 500ml serum bottle, add 400ml of anaerobic sludge, and pass nitrogen gas for 10 minutes. Place it in a shaking bed and maintain a temperature of 35°C. Anaerobic fermentation for 2 days.

[0049] Step three, pretreated fermented waste rice is washed, drained, and mixed with anaerobic sludge at a mass ratio of 0.25:1. Then it is added to the leaching tank 4, which has a volume of 1.5L (pre-filled with 0.5L of ceramic particles 5), and 4L of water is added daily.

[0050] Step four, the reaction is run for 13 days, and the cumulative COD production is 25573.33mg, as shown in Table 1.​Figure 2 The rice was soaked for only 13 days in this application example, but the COD releasing ability of the rice still exists.

[0051] The above only describes preferred embodiments of the application and is not intended to limit the application, and any modification, equivalent replacement or improvement made within the spirit and principle of the application should be included in the protection scope of the application.

Claims

1. A method for preparing a carbon source using waste rice, characterized in that, Includes the following steps: S1. Pretreatment: Waste rice is washed, dried, and then added to a fermentation tank. Anaerobic sludge is then added to the fermentation tank to obtain a mixed liquid. Nitrogen gas is continuously introduced into the fermentation tank to maintain an anaerobic environment. After the fermentation is completed, fermented waste rice is obtained, which is then washed and set aside for later use. The waste rice used is at least one of substandard rice, expired rice, or rice lost during processing. The waste rice is washed with clean water and then placed in the sun to dry on the surface. S2. Carbon source preparation using a carbon source tank: The carbon source tank includes a cylindrical, hollow carbon source tank body (1). One end of the carbon source tank body (1) is the water inlet (2), and the other end is the water outlet (6). A vertically placed rinsing tank (4) is detachably installed inside the carbon source tank body (1). The side wall of the rinsing tank (4) is mesh-like. The bottom of the rinsing tank (4) is filled with ceramsite (5). Anaerobic sludge and the washed fermented waste rice obtained in step S1 are placed on top of the ceramsite (5). The wastewater to be treated flows into the carbon source tank body (1) from the water inlet (2) and rinsing the fermented waste rice in the rinsing tank (4) so ​​that the fermented waste rice releases carbon source and flows out from the water outlet (6) into the wastewater treatment facility.

2. The method for preparing a carbon source from waste rice according to claim 1, characterized in that, In step S1, the mass ratio of waste rice to anaerobic sludge added to the fermentation tank is (0.2-0.3):

1.

3. The method for preparing a carbon source from waste rice according to claim 1, characterized in that, The fermentation tank in step S1 is equipped with a stirring device, the fermentation temperature is 30-50℃, and the fermentation time is 3-5 days.

4. The method for preparing a carbon source from waste rice according to claim 1, characterized in that, In step S2, the volume of the ceramsite (5) is 1 / 3 of the volume of the rinsing tank (4), and the bottom area of ​​the rinsing tank (4) is 1 / 9 of the bottom area of ​​the carbon source tank; the rinsing tank (4) is made of stainless steel and has multiple mesh openings on its side wall.

5. The method for preparing a carbon source from waste rice according to claim 1, characterized in that, The water inlet (2) is provided with multiple water inlets (3), and the water outlet (6) is provided with multiple water outlets (7). The water inlets (3) and water outlets (7) each occupy 1 / 16 of the bottom area of ​​the rinsing tank (4).

6. The method for preparing a carbon source from waste rice according to claim 1, characterized in that, In step S2, the mass ratio of fermented waste rice and anaerobic sludge in the rinsing tank (4) is (0.2-0.3):

1.

7. The application of a carbon source prepared by the method according to any one of claims 1-6 in wastewater treatment, characterized in that, Includes the following steps: a) Obtain water quality information of the influent and effluent of the wastewater to be treated area, and determine the amount of additional carbon source required for the effluent to stably meet the standards; b) Adjust the amount of fermented waste rice and anaerobic sludge in the rinsing tank (4) according to the required amount of additional carbon source; c) A vertically placed rinsing tank is detachably installed inside the carbon source tank. The assembled carbon source tank is placed in the sewage. The sewage to be treated flows into the carbon source tank from the inlet and rinses the fermented waste rice in the rinsing tank. The degradation rate of the fermented waste rice is calculated. The rinsing tank is cleaned regularly (4) and the fermented waste rice is replaced.

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