Laboratory Research On Ectopic Stabilization Pretreatment Technology Of Aged-refuse Solid Waste

There are more than 7 billion tons of domestic garbage in my country,covering more than 500 million square meters.It has serious environmental pollution problems,huge resource potential but very low conversion rate,and it has urgent demand for storage capacity and land release.This topic comes from the 2018 “Solid Waste Recycling” key special project “Non-hazardous disposal and secondary pollution prevention technology and equipment of age-refused solid waste”（2018YFC1901400）.It is part of the research content of Topic 4 “Technical equipment and demonstration of ectopic pretreatment,intelligent combined sorting and quality resource recycling of age-refused solid waste”（2018YFC1901404）.This topic studies the ectopic aerobic stabilization pretreatment technology of the age-refused solid waste.Researching on the aerobic stabilization evaluation method and the optimization of stabilization treatment process of age-refused solid waste in order to achieve the purpose of rapid and economic stabilization of age-refused solid waste.It is of great significance to improve the production efficiency and operating environment of the subsequent combined sorting process.In order to complete the research on aerobic stabilization evaluation method at small scale level,the TOC and AT₄ detection methods were optimized.A group of fixedbed aerobic stabilization experimental device operated on the conditions of appropriate temperature,moisture content and enough ventilation were designed to study the variations and the correlation between the two trends of total organic carbon（TOC）and4-day breathing intensity（AT₄）of the aged-refuse solid waste samples MW、GW、XW、WW、ZW、LW、FW、TW、HW obtained from Dongguan,Xiamen.In order to complete the research on aerobic stabilization evaluation method at large scale level,the ectopic stabilization plexiglass reactor was designed.Use the initial temperature change law to evaluate the heat per dry weight per unit time of the aged-refuse solid waste,indirectly reflect the law of the content of degradable components in aged-refuse solid waste.Evaluating the stabilization degree of the aged-refuse solid waste through these.Establishing the connection between the large-scale evaluation method and the small-scale evaluation method.The systematic and effective evaluation method for the degree of stabilization of the aged-refuse solid waste was obtained.Using the ectopic stabilization reactor to optimize the process of stabilizing the aged-refuse solid waste.Oxygen concentration was regulated which is the main factor affecting the aerobic stable operation.The lower limit of oxygen concentration of agedrefuse solid waste is optimized,and the optimal oxygen concentration range of each aged-refuse solid waste is set.The waste stabilization process is monitored through the TOC change trend and AT4 value,and nine kinds of aged-refuse solid waste stabilization cycles are obtained.By recording the number of opening times and single opening time of the fan during the stabilization process of nine types of aged-refuse solid waste,the total opening time of fan is obtained.Coordinating the stabilization operation efficiency and economic cost,and comparing the stabilization cycle and total opening time of fan before and after the optimization of oxygen concentration.The main conclusions are as follows:It proved that TOC measured by instrument was more reasonable.Relating that AT4 measures,sampling by the quartile method and calculating since the end of the lag period,have got more acceptable values than random sampling and since the commencement of microbial cultivation.It has the good correlations between TOC and AT4 evolution with time have been observed as well as their derivatives of aged-refuse solid waste MW、DW、XW、WW、ZW、LW、FW、TW、HW.The correlation coefficients obtained above are greater than 0.99（R₂>0.99）.It proved that the synchronization response law between TOC trend and AT4 trend.So we can use TOC trend that can be measured quickly to reflect AT₄ trend that cannot be detected quickly.Therefore,a new small scale method was conclued to comprehensively evaluate the aerobic stabilization degree of the age-refused solid waste based on the variation trend of TOC and the value of AT₄.Through the heat evaluation formula established on the large scale,the heat release of aged-refuse solid waste MW,DW,XW,WW,ZW,LW,FW,TW,and HW were 1.31C、0.91C、0.35C、0.77C、0.97C、1.88C、1.42C、2.46C、0.98 C at the initial stage,the results show that there is a significant primary correlation between the large-scale heat release Q0 and the small-scale AT4.Therefore,the large-scale stabilization standard can be deduced through the existing small-scale stabilization standard(AT₄<5mgO₂.g^-1DW).When Q₀ is less than 0.10 C,it can be considered that the solid waste has reached a stable state.The time required for the large-scale stabilization evaluation of the agedrefuse solid waste is 11.2min,14.6min,15 min,13.6min,13.4min,7.6min,13.8min,7.8min,13.2min,indicating that the large-scale level can quickly evaluate the stability of solid waste.The optimized oxygen concentration lower limit of aged-refuse solid waste MW,GW,XW,WW,ZW,LW,FW,TW,HW are 7.0%,6.0%,5.0%,6.0%,6.5%,7.5%,7.0%,8.0%,6.5%.Therefore,the optimal oxygen concentration ranges are 7.0%²1.0%,6.0%²1.0%,5.0%²1.0%,6.0%²1.0%,6.5%²1.0%,7.5%²1.0%,7.0%²1.0%,8.0%²1.0%,6.5%²1.0%.Operating under optimized oxygen concentration,the solid waste stabilization cycles are 6.5d,5.0d,2.5d,4.5d,5.0d,7.0d,6.5d,8.0d,5.5d,and the total opening time of fan are 169 min,112min,40 min,98.5min,129.5min,206.5min,192 min,252.5min,152 min.Operating under the empirical oxygen concentration conditions before optimization,the solid waste stabilization cycle is basically unchanged,and the total opening time of fan are 173.5min,121 min,45min,107 min,139.5min,214 min,197min,263 min,157min.It means that the running time of the fan after optimization is only slightly shorter than the running time of the fan before optimization.Compared with the inconvenience of operation caused by the inconsistency of the oxygen concentration lower limit of different aged-refuse solid waste,it is easier to operate in the empirical oxygen concentration range.