CN103819235B - A kind of rubbish from cooking aerobic fermentation treatment process based on regulation and control water morphology - Google Patents

Abstract

The invention discloses a kind of rubbish from cooking aerobic fermentation treatment process based on regulation and control water morphology, comprise the steps: that (1) is collected rubbish from cooking and carried out oily water separation, carry out fragmentation after removing impurity, obtain the rubbish from cooking after fragmentation; (2) water ratio regulating the rubbish from cooking after fragmentation is 50 ~ 75%, then mix with aerobic fermentation microbial inoculum, carry out aerobic fermentation, content to 15% ~ 25% of aerobe fermentation system total fiber element is regulated before aerobic fermentation starts, or water-holding agent is added in aerobic fermentation system, realize the regulation and control of water morphology in aerobic fermentation system more than kitchen.The present invention by the regulation and control of water morphology in regulation and control rubbish from cooking aerobic fermentation system, thus improves the efficiency of rubbish from cooking aerobic fermentation.

Description

A kind of aerobic fermentation treatment process of kitchen waste based on regulating moisture form

technical field

The invention relates to the technical field of aerobic fermentation of organic waste, in particular to an aerobic fermentation treatment process of kitchen waste based on regulating water form.

Background technique

Kitchen waste is a kind of organic waste, including leftovers, leftovers, vegetable leaves, fruit peels, eggshells, tea residues, bones, etc.

As a kind of organic waste, kitchen waste is rich in organic matter. In the actual treatment and disposal process, aerobic fermentation technology is often used to recycle kitchen waste. In the process of aerobic fermentation, water content is one of the key controlling factors. Excessively high water content will hinder the mass transfer of gas in the aerobic fermentation system, thus making the aerobic fermentation system tend to be anaerobic; too low water content It will inhibit the activity of microorganisms in the system, which is not conducive to the decomposition and humification of organic matter.

The water content will continue to decrease during the aerobic fermentation process. In order to keep the water content of the system in an appropriate range, it is usually achieved by supplementing water from an external source. However, water content is required during the storage, transportation and use of aerobic fermentation products. The rate is kept at a low level, so this part of the water added by exogenous sources needs to be removed in the later stage of aerobic fermentation, which virtually increases the cost of aerobic fermentation. By regulating the water form of the aerobic fermentation system of kitchen waste, the water content of the aerobic fermentation system can be improved without external water addition, and the stability and maturity of the aerobic fermentation system can be effectively promoted.

There are three forms of water in the aerobic fermentation system of kitchen waste, namely stagnant water, capillary water and bound water. Among them, stagnant water and capillary water can be used by microorganisms. At the same time, the difficulty of losing these three forms of water The sequence is bound water, capillary water and stagnant water.

Under certain conditions, these three forms of water can be transformed into each other and migrate. Therefore, by adjusting the form of water, the proportion of stagnant water that is easily lost can be reduced, thereby slowing down the rate of decline in water content and improving the treatment efficiency of the aerobic fermentation system. At the same time, it does not add dehydration pressure to the aerobic fermentation system of kitchen waste.

Contents of the invention

The invention provides an aerobic fermentation treatment process of kitchen waste based on adjusting the water form, and improves the efficiency of the aerobic fermentation of the kitchen waste by adjusting the water form of the aerobic fermentation system of the kitchen waste.

An aerobic fermentation treatment process for kitchen waste based on regulating water form, comprising the following steps:

(1) Collect kitchen waste for oil-water separation, remove impurities and then crush to obtain crushed kitchen waste;

(2) Adjust the moisture content of the crushed kitchen waste to 50% to 75%, and then mix it with an aerobic fermentation agent for aerobic fermentation. Add a conditioner before the start of aerobic fermentation to adjust the total cellulose in the aerobic fermentation system content to 15% to 25%, or add a water-retaining agent to the aerobic fermentation system.

There are three forms of water in the aerobic fermentation system of kitchen waste, namely stagnant water, capillary water and bound water. Among them, stagnant water and capillary water can be used by microorganisms. At the same time, the difficulty of losing these three forms of water The sequence is bound water, capillary water and stagnant water. Under certain conditions, these three forms of water can be transformed into each other and migrate. Therefore, by adjusting the form of water, the proportion of stagnant water that is easily lost can be reduced, thereby slowing down the rate of decline in water content and improving the treatment efficiency of the aerobic fermentation system. At the same time, it does not add dehydration pressure to the system.

Therefore, the present invention realizes the control of water form in the aerobic fermentation system of kitchen waste by adding water retaining agent and regulating the content of total cellulose in the aerobic fermentation system, thereby improving the efficiency of aerobic fermentation of kitchen waste.

The total cellulose is the sum of hemicellulose, cellulose and lignin.

Preferably, the particle size of the crushed kitchen waste in step (1) is 1 cm to 8 cm. More preferably, it is 5 cm.

Preferably, in step (2), a conditioner is added to the aerobic fermentation system to adjust the total cellulose content to 19.99%-22.69%.

Further preferably, the conditioner has a total cellulose content of 20%-45%; the dry weight ratio of kitchen waste to the conditioner is 1:3-1:1. The conditioner is preferably waste food.

In another preferred mode, in step (2), add a water-retaining agent to the aerobic fermentation system, the amount of the water-retaining agent added is 0.25%-2.00% of the wet weight of the aerobic fermentation system, and the water-absorbing ratio of the water-retaining agent is 150-400.

Further preferably, the water retaining agent is anionic polyacrylamide, water absorbent resin or starch grafted acrylate.

Further preferably, the water retaining agent is added before the aerobic fermentation system enters the high temperature period or at the beginning of the high temperature period. The temperature of the high-temperature fermentation period of the aerobic fermentation is 50-70°C.

Preferably, the fermentation time of the aerobic fermentation is 14-18 days. More preferably 16 days.

As a preference, the oxygenation method in the process of the aerobic fermentation is forced aeration or static turning, the aeration rate is 0.04L/(min.L)～0.1L/(min.L), and the turning frequency is 1 to 4 days.

In the aerobic fermentation system of kitchen waste, adjust the ratio of food waste and conditioner to control the total cellulose content in the aerobic fermentation system of kitchen waste, or add water retaining agent, so as to realize the water form in the aerobic fermentation system of kitchen waste Under the combination of the above-mentioned optimal conditions, during the period of 2 days to 6 days after the start of aerobic fermentation, the proportion of stagnant water to the total water is 55% to 70%, and the proportion of capillary water to the total water is 20% to 20%. 40%, bound water accounted for 2% to 15% of the total water; at the end of aerobic fermentation, stagnant water accounted for 80% to 92% of the total water, capillary water accounted for 5% to 15% of the total water %, bound water accounted for 4% to 7% of the total water.

The aerobic fermentation bacteria agent is isolated from kitchen waste, and is an indigenous bacterium in the kitchen waste system. It is a mixed bacteria system, and commercially used common fermentation bacteria agents (such as EM bacteria agent, Gymboree type I etc.), the addition of bacterial agents can shorten the fermentation period, and the addition amount is between 10 ⁸ and 10 ¹⁵ CFU/kg (wet weight).

The kitchen waste is the organic waste produced after eating and drinking.

The oil-water separation refers to placing the original kitchen waste on the screen to realize the separation between oil-water and kitchen waste.

The aerobic fermentation process is carried out in an aerobic fermentation device. The device is equipped with an aeration device, an online temperature monitoring device and a thermal insulation layer. It implements forced aeration or static turning, and the aeration rate is 0.04L/(min.L )～0.1L/(min.L), the turning frequency is 1～4 days.

Compared with the prior art, the present invention has the following beneficial effects:

By adding water-retaining agent and regulating the content of total cellulose in the aerobic fermentation system, the present invention realizes the regulation of the water form in the aerobic fermentation system of kitchen waste, thereby improving the efficiency of aerobic fermentation of kitchen waste.

Detailed ways

Example 1:

Raw materials for aerobic fermentation of kitchen waste: 12 kg of kitchen waste (moisture content 73.90±0.69%) and 6 kg of air-dried waste food materials (moisture content 12.85±0.22%) were taken from a canteen of a university in Hangzhou.

Take the supernatant after leaching kitchen waste and inoculate it into the inorganic salt medium with one of starch, glucose and protein as the carbon source, and screen out the bacterial groups with the function of degrading starch, glucose and protein respectively. The three types of bacteria were mixed and cultured in LB medium to obtain the desired bacteria solution.

The above-mentioned kitchen waste and air-dried discarded food materials were all crushed into a particle size of 5 cm, and then thoroughly mixed, and 18 ml of bacterial liquid with a concentration of 1×10 ¹⁵ CFU/mL was added, and the moisture content was adjusted to 60%, and finally the mixed material Divide into thirds.

The first part of the material is directly put into the aerobic fermentation device A; the second part of the material is added with a water-retaining agent (anionic polyacrylamide), the water retention rate is 200, and its mass is 0.5% of the wet weight, and then mixed evenly and put into the well in the oxygen fermentation device B; the third material is directly put into the aerobic fermentation device C, when the temperature of the system is stable at about 50°C, all the materials in the device C are taken out and added with water retaining agent (anionic polyacrylamide), Its mass is 0.5% of wet weight, mix well and refill in device C. The aeration rate of all devices is 0.05L/(min.L), and the aerobic fermentation time is 16 days.

During the aerobic fermentation, monitor the temperature in real time, take samples every two days, and measure the water content, stagnant water, capillary water and bound water. The initial sample and the sample at the end of aerobic fermentation also need to measure PHA (humic acid accounts for percentage of phytic acid). During the entire aerobic fermentation process, the temperature of device A reached 50°C at 80 hours, and the highest temperature in the process was 57.8°C; the temperature of device B reached 50°C at 24 hours, and the highest temperature in the process was 57.8°C; the temperature of device C reached 57.8°C at 72 hours. 50°C, and water retaining agent was added at 88h, the highest temperature during the process was 60.2°C. The initial PHA of device A was 8.86%, and the PHA at the end was 21.36%; the initial PHA of device B was 8.86%, and the PHA at the end was 24.07%; the initial PHA of device B was 8.86%, and the PHA at the end was 25.53%.

The water content, stagnant water, capillary water and bound water of devices A, B and C are shown in Table 1

Table 1

The data in Table 1 combined with the changes in temperature and PHA shows that the addition of water-retaining agent in the present invention has realized the regulation and control of water form, and adding water-retaining agent can accelerate the rise of system temperature and promote the system to reach a higher temperature, which is beneficial to the killing of pathogens in the system. and can increase the degree of humification of the system. Example 2

Raw materials for aerobic fermentation of kitchen waste: kitchen waste and discarded ingredients were taken from a canteen of a university in Hangzhou.

Kitchen waste and waste food materials are moderately air-dried, and the moisture content is maintained at about 60% after moderate air-drying. The total cellulose of kitchen waste accounts for 16.84% of the dry weight, and the total cellulose of waste food materials accounts for 25.11% of the dry weight.

Take the supernatant after leaching kitchen waste and inoculate it into the inorganic salt medium with one of starch, glucose and protein as the carbon source, and screen out the bacterial groups with the function of degrading starch, glucose and protein respectively. The three types of bacteria were mixed and cultured in LB medium to obtain the desired bacteria solution.

There are 5 sets of treatments, namely treatment 1 (100% waste food + 0% kitchen waste), treatment 2 (75% waste food + 25% kitchen waste), treatment 3 (50% waste food + 50% kitchen waste Garbage), treatment 4 (25% waste materials + 75% kitchen waste) and treatment 5 (0% waste materials + 100% kitchen waste), the mass of aerobic fermentation raw materials for each treatment is 6kg, and the moisture content is about 60%, the particle size is about 5cm, and 6ml of bacterial liquid with a concentration of 1×10 ¹⁵ CFU/mL is added to all treatments, and all treatments are fermented in an aerobic fermentation device. The aeration rate of all treatments was 0.05L/(min.L), and the aerobic fermentation time was 16 days.

During the aerobic fermentation, the temperature was monitored in real time, and samples were taken every two days to measure the moisture content, stagnant water, capillary water and bound water. Determine C/N.

In the process of aerobic fermentation, the highest temperature of treatment 1 was 52.3°C, and the time when the temperature was higher than 50°C was 8 days; the highest temperature of treatment 2 was 57.4°C, and the time when the temperature was higher than 50°C was 9 days, and there were The temperature was higher than 55°C for 5 days; the highest temperature of treatment 3 was 56.9°C, and the temperature was higher than 50°C for 8.5 days, and the temperature was higher than 55°C on 6 days within these 8.5 days; the highest temperature of treatment 4 was 56.1°C, The time when the temperature was higher than 50°C was 5.5 days; the highest temperature of treatment 5 was 56.9°C, and the time when the temperature was higher than 50°C was 4.5 days.

The percentages of total cellulose in dry weight of treatment 1, treatment 2, treatment 3, treatment 4 and treatment 5 were 25.11%, 22.69%, 19.99%, 17.93% and 16.84%, respectively.

The initial C/N of treatment 1 was 27.07, and the C/N at the end was 18.37; the initial C/N of treatment 2 was 31.00, and the C/N at the end was 15.26; the initial C/N of treatment 3 was 38.32, and the end The C/N of treatment 4 was 14.57; the initial C/N of treatment 4 was 42.71, and the C/N at the end was 18.65; the initial C/N of treatment 5 was 50.70, and the C/N at the end was 22.81.

See Table 2 for the water content, stagnant water, capillary water and bound water of Treatment 1, Treatment 2, Treatment 3, Treatment 4 and Treatment 5:

Table 2

Combining the data in Table 2 with the changes in temperature and C/N, it can be known that the present invention can regulate the water form by regulating the content of total cellulose in the aerobic fermentation system of kitchen waste. In this embodiment, the content of total cellulose is controlled at Between 19.99% and 22.69% can realize the decomposition of the aerobic fermentation system of kitchen waste while regulating the water form.

Claims (6)

1., based on a rubbish from cooking aerobic fermentation treatment process for regulation and control water morphology, it is characterized in that, comprise the steps:

(1) collect rubbish from cooking and carry out oily water separation, carry out fragmentation after removing impurity, obtain the rubbish from cooking after fragmentation;

(2) water ratio regulating the rubbish from cooking after fragmentation is 50% ~ 75%, then mixes with aerobic fermentation microbial inoculum, carries out aerobic fermentation, adds content to 15% ~ 25% that amendment regulates aerobe fermentation system total fiber element before aerobic fermentation starts.

2., according to claim 1 based on the rubbish from cooking aerobic fermentation treatment process of regulation and control water morphology, it is characterized in that, the particle diameter of the rubbish from cooking after fragmentation described in step (1) is 1cm ~ 8cm.

3., according to claim 1 based on the rubbish from cooking aerobic fermentation treatment process of regulation and control water morphology, it is characterized in that, in aerobic fermentation system, add amendment in step (2) to regulate content to 19.99% ~ 22.69% of its total fiber element.

4., according to claim 3 based on the rubbish from cooking aerobic fermentation treatment process of regulation and control water morphology, it is characterized in that, the total fiber cellulose content of described amendment is 20% ~ 45%; The dry weight ratio of rubbish from cooking and amendment is 1:3 ~ 1:1.

5., according to claim 1 based on the rubbish from cooking aerobic fermentation treatment process of regulation and control water morphology, it is characterized in that, the fermentation time of described aerobic fermentation is 14 ~ 18 days.

6. according to claim 1 based on the rubbish from cooking aerobic fermentation treatment process of regulation and control water morphology, it is characterized in that, in the process of described aerobic fermentation, oxygenation mode is forced aeration or standing turning, aeration rate is 0.04L/ (min.L) ~ 0.1L/ (min.L), and turning frequency is 1 ~ 4 day.