Study On Liquid Fertilization Technology Of Biogas Concentrate Concentrated In Livestock And Poultry

In recent years,livestock and poultry farming continue to intensive and large-scale development of livestock and poultry waste generated by the increasingly serious impact on the environment.According to statistics,the annual output of 10,000pig farms feces production capacity of 2190 tons,urine production capacity of 5200tons.Fecal and urine by biogas harmless treatment of biogas slurry for biogas fertilizer application is the current main sewage treatment and resource utilization,Biogas slurry is rich in N,P,K and organic matter and other nutrients,but the biogas slurry is low,transport and use of high cost,Resulting in some areas of biogas slurry can not be a reasonable use of direct efflux,resulting in more serious environmental pollution,Concentration of biogas slurry to reduce the volume of biogas slurry to improve the nutrient content of biogas slurry,thereby reducing the cost of biogas slurry is the future use of biogas slurry a development direction.This paper combines the characteristics of biogas slurry and how to produce high-value biogas manure,Firstly,the biogas slurry was pretreated by volcanic rocks,quartz sand and anthracite.And then by adding a slaked lime,PAM solution to reduce the biogas slurry and suspended solids,Finally,the biogas slurry was subjected to membrane concentration treatment by ultrafiltration membrane and reverse osmosis membrane device,In the liquid can meet the"comprehensive wastewater discharge standards"under the premise of high concentration of concentrated biogas slurry.The following conclusions are drawn from the experiment:（1）Using the"volcanic rock,quartz sand,anthracite"three filter system for biogas slurry filtration pretreatment,And then through the"hydrated lime+PAM"solution combined treatment of filtrate（Positive test）.With the highest removal rate of salt and suspended solids as the basis of the parameters,The preferred operating parameter values are:The feed rate of the three-stage filter system is 129L/h·m²,The filtration time was 240 min:1%concentration of hydrated lime solution dosage of13ml/100ml material,1‰concentration of PAM solution dosage of 2ml/100ml material,PH 8.9,standing time 30min.Under this preferred parameter,the EC value of the treatment liquid was 4.12 ms/cm,the decrease was 69.48%,Turbidity value of72NTU,a decrease of 97.13%,The concentrations of COD,TN,TP and ammonia in the biogas slurry were 962mg/L,230.74mg/L,11.26mg/L,58.23mg/L,The removal rates were 82.82%,52.72%,75.52%and 54.51%respectively.（2）Through the"slaked lime+PAM"solution combined treatment of biogas slurry,And then through the"volcanic rock,quartz sand,anthracite"three filter system on the treatment solution for filtration（reverse test）.The preferred parameters are:1%concentration of hydrated lime solution dosage of 15ml/100ml biogas slurry,1‰concentration PAM dosage of 4ml/100ml biogas slurry,PH 10,standing time45min;Three-stage filter system feed rate of 226L/h·m²,The filtration time is 150min.The EC value of the treatment liquid under this preferred parameter was 5.22ms/cm,A decrease of 61.33%,Turbidity value of 168NTU,A decrease of 93.30%,The COD,TN,TP and ammonia nitrogen concentrations of the biogas slurry were1105mg/L,237.26mg/L,12.24mg/L,63.89mg/L,The removal rates were 80.27%,51.38%,73.39%and 50.09%respectively.Through the positive test and direction test comparative analysis,The positive test was higher in EC,turbidity reduction and COD,TN,TP,ammonia removal rate than reverse test,And the amount of lime and PAM solution was lower than that of reverse test,Which can be determined by the first"volcanic rock,quartz sand,anthracite"three filter media,And then through the"slaked lime+PAM"solution treatment of the joint process（positive test）for the preferred process.（3）Ultrafiltration membrane equipment on the pre-optimized process after the biogas slurry is concentrated and then take the liquid,Under the conditions of pH 8.9,the preferred parameters are:Operating pressure 0.1MPa,where the operating temperature is 25℃.Concentration to 5 times when the liquid TN,NH₃-N concentrationreachedthehighest,Respectively,263.23mg/L,68.25mg/L.Concentration of TP through the liquid reached a maximum of 12.96mg/L,EC,pH did not change.According to the concentration of 5-6 times the concentration of TP is not much difference（5 times when concentrated liquid permeation TP concentration of 12.56mg/L）and process energy consumption considerations,select the concentration of 5 times.（4）Reverse osmosis membrane equipment for ultrafiltration membrane equipment after the solution through the concentration of treatment,The preferred parameters are:Operating pressure 1MPa,where the operating temperature is 25℃,pH 6.5.The whole process is preferred as"volcanic rock,quartz sand,anthracite three filter→slaked lime+PAM solution flocculation sedimentation→ultrafiltration membrane precision treatment→reverse osmosis membrane concentration treatment."Biogas slurry can reach the"Integrated Wastewater Discharge Standard"level emission standards（Cd,As,Pb can also discharge standards）,the biogas slurry can be concentrated to 4 times;Biogas slurry can meet the"Integrated Wastewater Discharge Standard"secondary emission standards（Cd,As,Pb can also discharge standards）,the biogas slurry can be concentrated to 5 times.Through liquid reaches level standard concentrate COD,TP,TN,NH₃-N concentration compared with the reverse osmosis membrane device feed liquid concentration respectively 3.82 times（966 mg/L）,3.46 times（220.42 mg/L）,3.47 times（43.42 mg/L）,3.9 times（3786mg/L）;Through the liquid reaches the secondary standard concentrate COD,TP,TN,NH3-N concentration compared with the reverse osmosis membrane device feed liquid concentration respectively 4.63 times（1170.03 mg/L）,4.11 times（261.32mg/L）,4.84 times（60.5 mg/L）,4.7 times（4575 mg/L）.