A Study On The Disposal Of Two Major Hazardous Waste In Guangzhou

As the frontier of China’s reform and opening up policy,Guangdong province’s industry develops rapidly.However,the hazardous wastes produced in Guangdong are various,multiple and complicated.Besides,the origins of the wastes are extensive and many industries are involved.The province is limited in facilities and capability of dealing with the wastes and some kinds of wastes can’t be disposed,which results in the accumulation of illegal disposition cases and large risks.As the capital city of Guangdong province,Guangzhou ranks first in its industrial development but still has the same problem.It is faced with great pressure of waste disposition.This thesis selects waste paint residue(HW12)and surface treatment sludge(HW17),two frequently seen hazardous wastes in Guangzhou as research objects which respectively account for 12-percent and 24-percent in the total amount of waste.They are mainly generated in the industries including automobile,shipbuilding,surface treatment,metal processing,spraying,printing,etc.At present,the methods of waste paint residue disposal are pyrolysis gasifier burning and rotary kiln incinerator processing while those of surface treatment sludge are drying and incineration and secure landfill.After comparing the technological processes,device functions,advantages and disadvantages and effects of these two disposal modes,it can be found that:(1)The rotary kiln incinerator flue gas cleaning system consists of reactor cooling tower,slaked lime dry absorption,activated carbon injection and bag filter,which can guarantee the up-to-standard discharge of waste gas and avoid secondary pollution.As the industries that generate waste paint residue are multiple,the quantity is large and the states are changeable,rotary kiln incinerator is more suitable.Besides,the rotary kiln incinerator devices in the factories in Guangzhou have operated for years and relevant techniques are quite mature and stable.(2)By contrast,when secure landfill is adopted,different proportions of cement,lime and heavy metal chelating agent can be added to conduct solidification in accordance with the situations and the solidification effect is fine and stable.Secure landfill costs less and can dispose large amounts of surface treatment sludge.In addition,the technique is mature,stable and efficient.(3)If drying and pre-treatment of crushing are implemented before the disposal of waste paint residue,the combustion area can be enlarged and efficiency can be improved.Pre-treatment of drying and solidification before disposal can reduce disposal amount,difficulty and the probability of producing secondary pollution in the process.If cement kiln is used for co-processing,the resource can be reused and operation cost can be saved.Moreover,it can play an important part in realizing “minimization,reclamation and harmlessness” of hazardous waste processing.(4)Guangzhou now for waste paint residue,surface treatment sludge has been used in rotary kiln incinerator disposal,safe landfill disposal.The flue gas purification system of rotary kiln incinerator can ensure the effective control of waste gas,the curing pretreatment technology of surface treatment sludge is mature and stable,and can ensure the effective control of heavy metals.These two disposal methods can be popularized in other cities of the same type.