An Introduction to Solid Wastes in Chongqing Municipality

An Introduction to Solid Wastes Management in Chongqing Municipality

I City Status As an economic, cultural and commercial center in the upstream of the Yangtze River, Chongqing municipality administers 40 districts and counties (boroughs) with an area of 82,000 km 2 and a population of 30.97 million. Topography in Chongqing is dominated by hills and mountains and climate is subtropical moist monsoon with annual average temperature19.4℃. Chongqing city proper, which is composed of YuZhong, Jiang Bei, Nanan and other districts with a population of 5.30million, is located at the confluence of the Yangtze and the Jialing rivers. Chongqing Environmental Protection Bureau (hereinafter CEPB) acts as an administration agency under the jurisdiction of Chongqing Municipal Government and implements a unified supervision management to environmental protection activities in Chongqing. For solid wastes management, CEPB advises and supervises environmental protection measures in resources utilization ， minimization and hazardous-free of domestic wastes taken by local (districts and counties)governments and Chongqing Municipal Administration Commission. CEPB also provide guidance and supervision to the commitment of industrial enterprises to solid waste pollution precautions directly or indirectly through local environmental departments. According to our current law and regulations on industrial solid waste, enterprises follows “Polluter Pays” Principal and develop hazardous-free treatment of industrial solid wastes under the supervision of environmental departments at all levels, alternatively, enterprises can hire a specialized company to do it. Any activities against law and regulations on solid wastes, environmental protection departments are authorized to implement administration sanctions. Currently, urban domestic refuse disposal in Chongqing city proper is charged based on RMB 3 yuan /household.month, which is mainly used for operation of domestic refuse disposal sites. Parts of remote districts/counties charge domestic refuse disposal following the standard in city proper while some parts of districts/ counties have not started charging. At present, local government provides subsidize for insufficient disposal charge of urban domestic refuse. A whole process of production, transportation, integrated utilization and hazardous-free disposal for hazardous solid wastes in Chongqing is forced to follow a transfer receipt system. Any organizations engaged in environmental pollution treatment, especially, in transport and integrated utilization of solid wastes, must be certified. According to the national stipulations, medical solid wastes in China are regarded as hazardous solid wastes and medical solid wastes in Chongqing city proper and its adjacent districts/counties are enforced to be centrally-treated.

II Existing Situation of Solid Wastes Management 7500 t domestic refuse is produced in Chongqing every day with 2.75 million t for the whole year, in which 3000t/d is from the city proper and 4500 t/d is from other districts and counties. Volume of domestic refuse in Chongqing is 410-500kg/m3 with average moisture of 50% and average thermal value of 3500- 4000kJ/kg. Inorganic composition in domestic refuse takes 40% and organics take 35%. There is a lower level of nitrogen, phosphorus and potassium. Components and chemical properties in domestic refuse of Chongqing are shown in Table 1 and Table 2. Table 1 Components of Domestic Refuse Category Organic components Inorganic Recovery Components Animals Plants Wood and Dust Pottery paper Robbery glass Metal bamboo and plastics Percentage 2.42 14.48 17.7 30.0 10.9 7.87 14.5 1.53 0.58 （%）

Table 2 Chemical Composition of Domestic Refuse

Items Nitrogen Total Total Total Total Total dust Others carbon hydrogen oxygen chloride sulfur level（%） 1.3 30.8 4.8 23.1 0.4 0.2 24.4 15.0 Collection rate of domestic garbage in Chongqing averages to 85%, in which urban domestic garbage in the city proper is collected and centrally-disposed by a specialized company under Chongqing Municipal Administration Commission with a collection rate of 98%.；while urban domestic refuse in other districts and counties is handled by local construction management councils or Chongqing Municipal Administration Bureau. Every year 13 million t industrial solid wastes are produced with main components of coal slag, coal breeze and coal stone, a comprehensive utilization rate of 71%, an annual emission of 1.6823 million t industrial solid wastes, an annual production of 448,400 t hazardous solid wastes. The comprehensive utilization quantity amounts to 251,100 t.

III Disposal of Domestic Refuse It is planned to construct 35 domestic garbage disposal sites with 3 of them in the urban area and 32 of them in the town center of district and counties. Chang Sheng Landfill Site is now under construction with a designed capacity of 1500/d,an investment of RMB457.64million yuan and designed service period of 20 Years; construction of Tong Xing incineration plant in the urban area is going to start with a designed capacity of 1000t/d, an investment of RMB350.00million yuan and a designed service period of 20 years; Hei Shi Zi sanitary landfill site in the urban area is designed by a capacity of 1000t/d and requires an investment of RMB380.million yuan （ collection system inclusive ） with 20 years service period. The proposed sanitary landfill sites in 13 districts and counties of Chongqing municipality along the Yangtze river are designed with a total capacity of 3000t/d, a total investment of RMB1153.97 million yuan. Among them, landfill sites in Feng Jie, Wan Zou, Shi Zhu, Hu Ling and Jiang Jin districts/counties have entered construction stage with a total investment of RMB393.83million yuan and other landfill sites have finalized the engineering design and are going to enter construction stage. A technical plan of “Screening-Landfill-Incineration Power Production” is proposed to centrally treat 1700t/d refuse by regions produced in 11 comparatively centralized districts/counties, i.e, small-scaled screening landfill sites are respectively constructed in the above-mentioned districts/counties, hard-to-burn refuse is filled sanitarily in the land after “Decomposing” (Due to a “Decomposing” stage for hard-to-burn before sanitary landfill, no leakage or little leakage is leached to have an easy control of secondary pollution). 2-3 coal-fired will be technically renovated to be chosen as sites for refuse incineration power plant and incineration plant in a comparatively centralized way by regions. Economic transportation distance ranges between 28-94km. Following the principal of “Government Guidance and Market Operation”, a specialized company is accredited to be responsible for the business activities and the technology-related researches in the whole process of collection, screening, landfill and incineration power. Calculated based on 15 years service period, the approach of “Screening-Landfill-Incineration Power Production” can reduce 30-50% landfill volume, save 10-15% of investment. Total capacity of power generators for refuse incineration amounts to 5500kW with annual power production of 43 43 million kWh.

IV Problems to be solved Charge policy for collection and disposal of domestic refuse in Chongqing needs to be improved and it is planned to start charging collection and disposal in the whole municipality and gradually increase charging standard. Meanwhile. It is also required to issue a price for electricity produced by incineration of domestic refuse. Due to the unique topography in Chongqing, the proposed investment of many landfill sites is obviously higher than that of the same scale landfill sites in other parts of China. It is mainly explained by a higher engineering cost. The constructed or proposed landfill sites in districts/counties are decentralized comparatively and cover much land with small daily treatment capacity and higher operation cost.

V Conclusions It is proposed that, due to financial difficulties encountered by the developing counties in constructing refuse treatment facilities, loan borrowed from foreign government or BOT approach be considered. Operation of facilities and loan repayment can be guaranteed by rational disposal charge.