CN102964044A

CN102964044A - Method for improving performance of methane produced by anaerobic reaction on manure

Info

Publication number: CN102964044A
Application number: CN2012105334599A
Authority: CN
Inventors: 李秀金; 刘茹飞; 邹德勋; 袁海荣; 朱保宁
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2012-12-12
Filing date: 2012-12-12
Publication date: 2013-03-13

Abstract

The invention discloses a method for improving performance of methane produced by anaerobic reaction on manure, and the method comprises the following steps of: mixing manure with sludge after centrifugation or sedimentation in total solid weight ratio of (1-2):(2-1), placing a mixed material into an anaerobic digestion reactor, adding inoculated sludge, and reacting under the low temperature, middle temperature or high temperature condition. The method disclosed by the invention has the advantages that the process is simple, the operability is strong, two or more than two organic solid wastes can be treated at the same time, and the unit volatile solid gas yield is improved by 4.7-6.8 times compared with that of separate manure.

Description

A kind of method that improves human excrement anaerobic methane production gas performance

Technical field

The invention belongs to the organic solid waste process field, concrete is to relate to a kind of method that improves human excrement anaerobic methane production gas performance.

Background technology

China produces the maximum country of organic waste in the world, wherein annual 2141 ten thousand tons human excrement, 2,200 ten thousand tons the mud of producing.These organic waste will cause great harm to human health and ecotope as effectively not processing.At present, the processing of human excrement is mainly take the research of innoxious and Fertilizer Transformed as main, discloses the treatment process that the city human excrement is produced fertilizer such as patent 1850736A, by separation, granulation, sterilization and the drying and other steps of human excrement being realized effective utilization of human excrement.But the method needs Special Equipment, invests greatlyr, and product application is limited.Anaerobic digestion is a kind of technology that organic waste can be carried out harmless treatment and can be translated into clean energy, is one of main development direction of following organic waste processing.Yet, at present less to the research of human excrement anaerobic digestion, studied the impact of temperature on the human excrement anaerobic digestion such as Zhang Cuili etc., show that human excrement its aerogenesis under 25 ℃ of conditions is best, reach 30.2L(" temperature is on the impact of 4 kinds of different ight soil anaerobic digestion gas production efficient and digestion time " [J]. Transactions of the Chinese Society of Agricultural Engineering, 2008,24 (7): 209-212.).But these processing modes are bad to the innoxious effect of human excrement, and its anaerobic digestion gas production amount is lower.

Independent human excrement material ratio is easier to acidifying, causes VFA in the anaerobic System (VFA) accumulation, and pH descends, and then inhibition methanogen physiologically active, thereby cause its gas generation property to reduce, even the anaerobic digestion failure, can not satisfy large-scale biogas production needs fully.Therefore, in order to improve the anaerobic digestion efficient of human excrement material, itself and other organic materials can be united and carry out anaerobic digestion.Mud is the organic waste that a kind of organic content is high, water ratio is high, pH is higher.Therefore, the present invention considers human excrement is mixed adjusting with mud, and suitable pH value and the entry condition of control carried out anaerobic digestion.The method can not only overcome the deficiency of single material anaerobic digestion, can improve the required nutritive element of anaerobion simultaneously, makes various raw materials remedy mutually separately shortcoming, produces and has complementary advantages, and makes its advantage maximization, jointly improves biogas output.

Summary of the invention

The object of the invention is to provide a kind of method that human excrement produces the biogas performance that improves, the method that the human excrement that the present invention proposes and mud mix, can be that mixture reaches suitable pH value and entry condition, and improve the required nutritive element of microorganism existence, the method can solve the problem that single human excrement raw material anaerobic digestion exists, thereby for engineering practice with improve gas production rate foundation is provided.

The invention provides a kind of method that human excrement produces the biogas performance that improves, it is characterized in that:

With human excrement with outwell mud after the supernatant liquor through centrifugal or sedimentation and fully mix in anaerobic digestion reaction vessel with the ratio of total solids mass ratio 1:0.5-2 and carry out anaerobically fermenting, following ratio is as being total solids (TS) mass ratio without explanation; It is 13000-17000 mg/L that institute adds the inoculation sludge quantity, preferable range 14000-16000 mg/L, adding the load that the water constant volume makes material in the reactor is 50gTS/L-80gTS/L, be in the anaerobic digestion optimum range, the sealing anaerobic digestion reaction vessel, under temperature of reaction control low temperature, middle temperature or a certain condition of high temperature, provide in the anaerobic digestion process and continue to stir or artificial the mixing, can produce biogas in 12 hours.

Be further characterized in that human excrement can be fresh human excrement or septic tank ight soil, septic tank ight soil is processed through centrifugal treating or sedimentation.

Be further characterized in that mud can be primary sludge, excess sludge and dewatered sludge, primary sludge and excess sludge are processed through centrifugal treating or sedimentation.

Be further characterized in that centrifugal and purpose sedimentation is to reach the load that reaction requires, the centrifugal and complete feature of sedimentation is that total solids is greater than the load that requires.

Be further characterized in that described fermentation time continued more than 25 days, preferably continue more than 30 days, further preferred lasting more than 40 days.

Measure gas production rate and gas ingredients every day, work as CH ₄Content reaches 50% when above, thinks to enter the methanation stage.Through anaerobic digestion in 25-40 days, when gas production rate obviously descends, when the same day, gas production rate was lower than the 5%-10% of reactor volume, think that anaerobic digestion gas production finishes.

Human excrement material and the high municipal sludge hybrid anaerobic fermentation of basicity with easy acidifying, under the organic loading condition of 50 gTS/L, 65 gTS/L, 80 gTS/L, carry out anaerobic digestion respectively, human excrement and outwell mud after the supernatant liquor through centrifugal or sedimentation and fully mix with the ratio of 1:0.5-2 and carry out anaerobically fermenting, ratio human excrement and the primary sludge recommended mix with 1:1, and institute adds sludge quantity and is; 15000mg/L, this moment, gas generation property was optimum, and VFA (VFA) accumulation does not appear in this moment in the reaction system, and aerogenesis is stable.The ammonia nitrogen value of Digestive system is 71 mg/L-160 mg/L, can not cause inhibition to anaerobic digestion.

Technique of the present invention is simple, and is workable; The mud mixing anaerobic digestion of the method after with human excrement and centrifugal or sedimentation has not only been processed simultaneously two kinds and above organic solid waste, and has been improved the biological transformation ratio of biomass in the various mixing of materials anaerobic digestions, has improved the gas generation property of human excrement.

Description of drawings

Fig. 1: different material odd-numbered day gas production rate;

Fig. 2: different material cumulative gas production;

Fig. 3: the VS of different material unit gas production rate.

Embodiment

The present invention will be further elaborated below by embodiment:

Embodiment 1

The biogas performance is produced in human excrement and the digestion of primary sludge different ratios mixing anaerobic:

Primary sludge after human excrement and centrifugal or the sedimentation is fully mixed in the ratio (wherein 1:0 and 0:1 are respectively pure mud and pure human excrement) of total solids mass ratio 1:0,1:1,2:1,1:2,0:1;

The compounding substances of gained is put into the Erlenmeyer flask anaerobic digestion reaction vessel of 2L, the digested sludge of inoculation sewage work, fully mix, the addition of seed sludge is that the 13000-17000mg/L(quality is in TS), preferred 15000mg/L adds the water constant volume to the 1.5L working volume;

The organic loading of material is respectively 50gTS/L, 65gTS/L, 80gTS/L in the conditioned reaction device, and this moment is totally 3 loads, each 5 kinds of ratio of loading.Close the Erlenmeyer flask anaerobic digestion reaction vessel with rubber plug sealing, the reactor air outlet links to each other by the device of pneumatic tube with draining note gas, temperature of reaction is controlled at (35 ± 2) ℃ by water-bath, provides every day twice abundant stirring by manpower in the anaerobic digestion process, can produce biogas in 12 hours.

Through anaerobic digestion in 30-40 days, gas production rate obviously descended, and when the same day, gas production rate was lower than the 5%-10% of reaction volume, thought that anaerobic digestion gas production finishes.

Measure the biogas output in the bomb every day, daily gas spirogram and cumulative gas production figure see Fig. 1,2; Unit VS gas production rate is seen Fig. 3.Unit VS gas production rate represents the gas production rate of every gram volatile organic matter, generally is used for weighing the product biogas performance of material.The result shows take primary sludge and human excrement dry-matter ratio as the cumulative gas production of 1:1 the highest, and wherein the VS of the unit gas production rate under the 50gTS/L can reach 498.6ml, is the maximum value in all proportions and the load.The ammonia nitrogen value of reactor is 616mg/L-1918mg/L, and within useful scope, basicity value is 2920mg/L-19800mg/L, and good system buffer ability is arranged.

When being understood that; specific embodiments of the invention only are the purposes of property explanation presented for purpose of illustration; it limits the protection domain of patent of the present invention never in any form; those skilled in the art can be improved or conversion according to the above description, and all these improvement and conversion all should belong to the protection domain of patent claims of the present invention.

Claims

1. method that improves the human excrement anaerobic digestion methane production is characterized in that: human excrement is mixed in the ratio of total solids mass ratio 1:0.5-2 with mud after centrifugal and/or sedimentation are processed; Mixed material is put into anaerobic digestion reaction vessel, add seed sludge, used seed sludge is the digested sludge of sewage work and/or methane station, its pH value is 7.0-8.2, total solids TS is 3%-13%, and the ammonia nitrogen value is preferably 100-800mg/L less than 2000mg/L, stirring makes mixing of materials, and the addition of seed sludge is 13000-17000mg/L; Adding the concentration that the water constant volume makes material in the reactor is 50g-80gTS/L, control charging pH is 7.2-7.6, carries out or does not carry out carbon-nitrogen ratio and regulate, the sealing anaerobic digestion reaction vessel, temperature of reaction provides in the anaerobic digestion process and continues to stir or artificial the mixing between 13-57 ℃.

2. the method for product biogas according to claim 1 is characterized in that human excrement can be fresh human excrement or septic tank ight soil, and septic tank ight soil is processed through centrifugal treating or sedimentation.

3. the method for product biogas according to claim 1 is characterized in that it is primary sludge, excess sludge and/or dewatered sludge that mud is selected from, and primary sludge and excess sludge are processed through centrifugal treating or sedimentation.

4. the method for product biogas according to claim 1 is characterized in that described fermentation time continued more than 25 days, preferably continues more than 30 days, and is further preferred lasting more than 40 days.

5. the method for product biogas according to claim 1 is characterized in that the basicity value of mixture greater than 2000mg/L, is preferably 2850mg/L-8690mg/L.

6. the method for product biogas according to claim 1 is characterized in that controlling temperature of reactor and keeps substantially constant, and temperature controlling range is temperature (33-37 ℃) or high temperature (53-57 ℃) in the low temperature (13-17 ℃) preferably, is preferably high temperature.