Effects Of Passivators On Heavy Metals Cd,Ni,Cu Content And Speciation In Anaerobic Fermentation Of Cattle Manure

With the rapid development and application of feed breeding method of livestock husbandry in our country,heavy metal residues in livestock and poultry manure has become a serious problem.The anaero-bic fermentation is an effective way for the treatment of livestock manure,and the temperature effect on heavy metal passivator in anaerobic fermentation of dairy manure,there is less research,so through this research for heavy metal pollution control and safe utilization of biogas fertilizer to provide a scientific ba?sis.This paper tests to heavy metals as the research object,the anaerobic fermentation of cow dung as raw material,anaerobic fermentation passivation add 3 different types and the proportion of added agents,by the method of orthogonal experiment,3 factors were selected in the experiment,each factor 3 levels;3 fac-tors are temperature(selected from 3 levels respectively,22 C,28 C,35 C),passivation agent(selected from 3 levels respectively,zeolite,sepiolite,calcium magnesium phosphate),passivation agent proportion(select 3 water Don't split for the dry weight of 5%,2.5%,7.5%),using BCR extraction method for specia-tion analysis of heavy metals,explore three different passivation agent(zeolite,sepiolite,calcium magne-sium phosphate)on gas production in anaerobic fermentation of dairy manure,content and chemical forms of heavy metals of methane,through this study,to provide scientific basis for reasonable use biogas slurry safety.In the inoculum amount 30%,TS 10%,pH 7,temperature 22 C,28 C,35 C 60d cattle manure anaero-bic fermentation conditions,according to L9(34)to arrange the test,the test of different treatments on cat-tle manure anaerobic fermentation of heavy metals Cd,Ni,fermentation test,influence of Cu content and form,research to explore the different treatment on anaerobic fermentation of cattle manure biogas produc-tion,the average methane content,effect of anaerobic fermentation of cattle manure on heavy metal pas-sivation ability and the proportions of available.The main conclusions are as follows:(1)The test results showed that adding passivator delayed the gas production peak;adding passivator is conducive to the increase of cattle manure anaerobic fermentation gas production;temperature and pas-sivation agent proportion had significant effects on the cumulative gas production,and passivation agents on the biogas production effect is not significant,through the analysis of volumetric gas production the highest rate of treatment,the temperature is 35?,adding 5%cow dung anaerobic fermentation processing of sepiolite,volumetric gas production rate of 0.285m3/m3·d.the test results showed that adding passivation agent to increase the average methane content under the same temperature conditions,the higher the tem-perature the higher the temperature,the content of methane;passivation agent and passivation agent addi-tion on biogas production were significantly affected,processing through the analysis of the methane con-tent is higher,the temperature of 35?,add 5%sepiolite cow dung anaerobic fermentation process,the av-erage methane content reached 54.87%.(2)By comparing the addition of passivator,treatment without passivation agent(i.e.blank treatment)and Cd before fermentation the total,passivation agents had significant effect on heavy metal Cd pas-sivation ability,passivation agent dosage has significant effect on metal Cd passivation ability,through the analysis of the heavy metal Cd passivation treatment is the highest,at a temperature of 28?,adding 7.5%cow dung anaerobic fermentation processing of sepiolite on heavy metal Cd passivation ability to reach the temperature of the 63.27%.passivation agent had significant effect on the effective state of heavy metal Cd proportion,passivation agent dosage has a significant impact on the proportions of available metal Cd,through the analysis of the treatment of cattle manure anaerobic fermentation of available heavy metals Cd the lowest proportion is 35?,cattle manure anaerobic fermentation process adding 2.5%calcium magne-sium phosphate,heavy metals Cd State the ratio of 42.20%.in general,which is propitious to the anaerobic fermentation of cattle manure harmless tend to heavy metal Cd passivating agent added,Cd heavy metals mainly enriched in biogas,biogas residue in the proportion of Cd in 52.04%-75.64%.(3)By comparing the addition of passivator,treatment without passivation agent(i.e.blank treatment)and Ni before fermentation the total,passivation agents had significant effect on the passivation ability of heavy metal Ni,and the passivation effect of the adding quantity of metal Ni the passivation ability is not significant,through the analysis of the heavy metal Ni passivation treatment is the highest,the temperature of 35 ?,adding 5%cow dung anaerobic fermentation processing of sepiolite on heavy metal Ni passivation ability to reach the temperature of the 45.76%.passivation agent dosage on the effective state of heavy metal Ni proportion has a significant effect,and the passivation agents on the metal Ni available the pro-portion is not significantly affected,through the analysis of the treatment of cattle manure anaerobic fer-mentation of available heavy metals Ni the lowest proportion is 35 ?,adding 5%cow dung anaerobic fer-mentation processing of sepiolite,heavy metal availability ratio is 4 Ni 5.76%.in general,which is propi-tious to the anaerobic fermentation of cattle manure harmless tend to heavy metal Ni passivating agent added,Ni heavy metals mainly enriched in biogas,biogas residue in the proportion of Ni in 58.59%-70.16%.(4)By comparing the addition of passivator,treatment without passivation agent(i.e.blank treatment)and Cu before fermentation the total,temperature,passivation agent addition had significant effect on heavy metal Cu passivation ability,passivation agent has significant effect on metal Cu passivation ability,through the analysis of the heavy metal Cu passivation treatment is the highest,the temperature of 28?,cow dung anaerobic fermentation process with 2.5%zeolite,heavy metals Cu passivation ability to reach the temperature of the 60.19%.passivation agent available for heavy metal species proportion of Cu has significant effect,and the influence of the amount of metal passivation agent Cu the proportion of state was obtained by analyzing the treatment of cattle manure anaerobic fermentation of available heavy metals Cu the lowest proportion is 35?,cattle manure anaerobic fermentation process adding 2.5%calcium magne-sium phosphate,heavy metal availability ratio of Cu 25.78%.in general,which is propitious to the anaero-bic fermentation of cattle manure harmless tend to heavy metal Cu passivating agent added,Cu heavy met-als mainly enriched in biogas,biogas residue in the proportion of Cu in 50.68%-62.92%.(5)22? the treatment of heavy metals Cd,Ni,Cu effective passivation effect were 3.15%-23.22%,11.94%-25.11%,14.01%-80.99%.for the best,adding 5%zeolite on the bioavailability of heavy metal passivation effect order:Cu>Ni>Cd.35 C,all of the heavy metals of Cd,Ni,Cu effective passivation the effects were 4.44%-20.16%,23.54%,75.15%-77.51%.is the best,adding 7.5%zeolite treatment and add-ing 2.5%calcium magnesium phosphate processing,order of passivation effect on heavy metals are:Cu>Ni,Cd.28 C,the treatment of heavy metals Cd,Ni,Cu effective passivation effect were 28.51%-30.73%,37.97%-76.89%,treatment the optimal order for 1.9%-76.45%.,adding 2.5%passivation effect of zeolite on heavy metals was:Ni>Cu>Cd.