Preparation method of iron series additive and method for increasing anaerobically produced methane

An anaerobic methane production and additive technology, applied in waste fuel, fermentation and other directions, can solve the problems affecting the resource utilization of biogas residue and biogas slurry, high treatment and disposal costs, and increased iron dosage, and achieve resource utilization. , the effect of reducing the amount of iron added and operating costs, and promoting the production of methane

Inactive Publication Date: 2018-09-04

NANJING FORESTRY UNIV

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AI-Extracted Technical Summary

Problems solved by technology

However, the added iron easily reacts with anions, organic or inorganic substances in the reactor to form precipitates, which not only increases the dosage of iron and increases the operating cost, but also affects the resource utilization of bioga...

Method used

[0081] In summary, the embodiments of the present invention provide the use of low-frequency ultrasonic generator to extract EPS solution from excess sludge as a chelating agent, and FeCl2 reaction to prepare Fe-EPS additive. In addition, Fe-EPS is added to the anaerobic digestion reactor of kitchen waste to produce methane, which greatly increases the anaerobic biogas production rate and the correspond...

Abstract

The invention relates to a preparation method of an iron series additive and a method for increasing anaerobically produced methane, and belongs to the technical field of organic waste treatment. Themethod comprises the following specific steps: (1) using a low frequency ultrasonic generator to treat excess sludge of a municipal sewage treatment plant; (2) using a centrifugal machine to carry outsolid-liquid separation on the treated sludge, and extracting an extracellular polymeric substance (EPS); (3) slowly dissolving ferrous chloride (FeCl2) into the EPS, and stirring to obtain the ironseries additive Fe-EPS; (4) adding the Fe-PES into an organic waste anaerobic digestion reactor with relatively low iron background value, and carrying out a long-term methanogenesis reaction in an intermediate temperature condition; and (5) collecting and analyzing the yield of biogas and the content of methane, and evaluating the operation stability of the reactor. Iron precipitation can be avoided effectively, the efficiency of methanogenesis is improved, and simultaneously, the resource utilization of excess sludge and organic wastes is realized.

Application Domain

Waste based fuelFermentation

Technology Topic

Municipal sewageChemistry +13

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Examples

Experimental program(3)
Effect test(1)

Example Embodiment

[0055] Example 1

[0056] This embodiment provides a method for preparing an iron-based additive and improving anaerobic methane production, which is implemented in the above-mentioned anaerobic digestion device, and specifically includes the following steps:

[0057] After washing the food waste with tap water, manually pick out the bones, plastic products, paper towels and other sundries in the food waste, and then heat and mash the food waste to <2mm.

[0058] The collected sludge from the secondary settling tank of the municipal sewage treatment plant was filtered through a 1mm sieve, and then allowed to stand for 24 hours at 4°C. After the supernatant was discharged, the sludge was ultrasonically treated with a 20kHz low frequency ultrasonic generator (1.0 W/mL, 5min). The remaining sludge after ultrasonic treatment was centrifuged for 10 min with a centrifuge (8000 rpm) to obtain an EPS solution. 400mg FeCl 2 The solid was slowly added to 1L EPS solution and stirred to prepare Fe-EPS additive.

[0059] In this example, a total of 4 sets of anaerobic digestion devices with a total volume of 10L are set up. In the initial stage of the reaction, 4.5L of food waste and 1.5L of inoculation sludge are respectively loaded into each set of anaerobic digestion devices. Nitrogen gas was passed through the oxygen digestion device for 15 minutes to exhaust air.

[0060] The material in the anaerobic digestion reactor 1 is stirred with an electric stirrer 2, the speed is controlled to 100 rpm by the speed control device 3, and the temperature of the anaerobic digestion reactor 1 is controlled at 35°C by the water bath heating device 6, and At the same time, a drainage gas collecting device (water-sealed bottle 4 and measuring cylinder 5) is used to collect the biogas generated in the anaerobic digestion reactor 1. In addition, it should be emphasized that during the anaerobic digestion reaction process in this embodiment, the dosage rate of food waste is 6%.

[0061] The automatic timer is used to control the switches of the feed pump 9 and the discharge pump 10 to control the feeding and discharging. While feeding, the Fe-EPS added to the fourth set of anaerobic digestion unit is 100mg/gVS (with Fe Calculate), add FeCl equivalent to the fourth set into the second and third sets of anaerobic digestion units respectively 2 And EPS, the first set was used as a control group (without any additives).

Example Embodiment

[0062] Example 2

[0063] This embodiment provides a method for preparing an iron-based additive and improving anaerobic methane production, which is implemented in the above-mentioned anaerobic digestion device, and specifically includes the following steps:

[0064] After washing the food waste with tap water, manually pick out the bones, plastic products, paper towels and other sundries in the food waste, and then heat and mash the food waste to <2mm.

[0065] The collected sludge from the secondary settling tank of the municipal sewage treatment plant was filtered through a 1mm sieve, and then allowed to stand for 24 hours at 4°C. After the supernatant was discharged, the sludge was ultrasonically treated with a 20kHz low frequency ultrasonic generator (1.0 W/mL, 5min). The remaining sludge after ultrasonic treatment was centrifuged for 10 min with a centrifuge (8000 rpm) to obtain an EPS solution. 400mg FeCl 2 The solid was slowly added to 1L EPS solution and stirred to prepare Fe-EPS additive.

[0066] In this embodiment, a total of 4 sets of anaerobic digestion devices with a total volume of 10L are set up. In the initial stage of the reaction, 4.5L of food waste and 1.5L of inoculation sludge are respectively loaded into each set of anaerobic digestion devices, Nitrogen gas was passed through the oxygen digestion device for 10 minutes to discharge air.

[0067] The material in the anaerobic digestion reactor 1 is stirred with an electric stirrer 2, the speed is controlled to 110 rpm by the speed control device 3, and the temperature of the anaerobic digestion reactor 1 is controlled at 35°C by the water bath heating device 6, and At the same time, a drainage gas collecting device (water-sealed bottle 4 and measuring cylinder 5) is used to collect the biogas generated in the anaerobic digestion reactor 1. In addition, it should be emphasized that during the anaerobic digestion reaction in this embodiment, the dosage rate of food waste is 8%.

[0068] The automatic timer is used to control the switches of the feed pump 9 and the discharge pump 10 to control the feeding and discharging. While feeding, the Fe-EPS added to the fourth set of anaerobic digestion unit is 150mg/gVS (with Fe Calculate), add FeCl equivalent to the fourth set into the second and third sets of anaerobic digestion units respectively 2 And EPS, the first set was used as a control group (without any additives).

Example Embodiment

[0069] Example 3

[0070] This embodiment provides a method for preparing an iron-based additive and improving anaerobic methane production, which is implemented in the above-mentioned anaerobic digestion device, and specifically includes the following steps:

[0071] After washing the food waste with tap water, manually pick out the bones, plastic products, paper towels and other sundries in the food waste, and then heat and mash the food waste to <2mm.

[0072] The collected sludge from the secondary settling tank of the municipal sewage treatment plant was filtered through a 1mm sieve, and then allowed to stand for 24 hours at 4°C. After the supernatant was discharged, the sludge was ultrasonically treated with a 20kHz low frequency ultrasonic generator (1.0 W/mL, 5min). The remaining sludge after ultrasonic treatment was centrifuged for 10 min with a centrifuge (8000 rpm) to obtain an EPS solution. 400mg FeCl 2 The solid was slowly added to 1L EPS solution and stirred to prepare Fe-EPS additive.

[0073] In this embodiment, a total of 4 sets of anaerobic digestion devices with a total volume of 10L are set up. In the initial stage of the reaction, 4.5L of food waste and 1.5L of inoculation sludge are respectively loaded into each set of anaerobic digestion devices, Nitrogen gas was passed through the oxygen digestion device for 10 minutes to exhaust air.

[0074] The material in the anaerobic digestion reactor 1 is stirred with an electric stirrer 2, the speed is controlled to 100 rpm by the speed control device 3, and the temperature of the anaerobic digestion reactor 1 is controlled at 35°C by the water bath heating device 6, and At the same time, a drainage gas collecting device (water-sealed bottle 4 and measuring cylinder 5) is used to collect the biogas generated in the anaerobic digestion reactor 1. In addition, it should be emphasized that during the anaerobic digestion reaction process in this embodiment, the dosage rate of food waste is 6%.

[0075] The automatic timer is used to control the switches of the feed pump 9 and the discharge pump 10 to control the feed and discharge. While feeding, the Fe-EPS added to the fourth set of anaerobic digestion unit is 50mg/gVS (with Fe Calculate), add FeCl equivalent to the fourth set into the second and third sets of anaerobic digestion units respectively 2 And EPS, the first set was used as a control group (without any additives).

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Preparation method of iron series additive and method for increasing anaerobically produced methane

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

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Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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