evolution, hydrogeological conditions, existing monitoring wells (distribution,
depth and etc.), regular monitoring and environmental management, as well as
surrounding environment. For example, environmentally sensitive sites in the
surrounding area are investigated to make clear their quantity, category, distribution, impact, protective measures, geographical location, scale, position relative to
landfills, environmental functional area and surrounding land use (Hong et al. 2011;
Wang and Ji 2010; Yang et al. 2010).
The risk factors of uncontrolled landfills are preliminarily identified, including
waste hazard, potential groundwater contamination and the impact on the surrounding environment. Each risk factor is carefully divided into multiple indicators
that together form an environmental risk assessment indicator system for uncontrolled landfills (Liu 2013; Wang 2013).
Risk assessment indicators for waste hazard are listed below:
• Landfill volume: Total amount of waste landfilled (m
3 );
• Landfill period: A longer period of landfill means that the stock waste is more
stable and likely less harmful to the environment;
• Landfill type: Toxic waste, MSW, MSW mixed with construction waste, rural
solid waste, construction waste (in descending order of risk);
• Organic content: <9%, 9–16%, 16–20%, or >20% (in ascending order of risk);
• Seepage control: Two composite anti-seepage layers, single composite
anti-seepage layer, impervious clay, or natural-soil bottom layer (in ascending
order of risk);
• Leachate collection: Collection and treatment system, collection system only, or
no collection system (in ascending order of risk).
3.1.2 Characteristic Factors of HWLFs Hazards
Through data collection, on-site interview and field investigation, it is found that
typical HWLFs waste in various regions of China mainly come from the industrial
sector and are dominated by hazardous wastes containing heavy metals. Typical
hazardous wastes include fly ash, slag, and sludge containing heavy metals. Since
heavy metals are highly stable and do not decompose under the action of
microorganisms, hazardous waste containing typical heavy metals will pose persistent toxicity hazard. Moreover, the leachate generated under the external conditions such as rain or acid rain is also harmful by producing long-term
environmental hazards. Leakage sources formed due to lack of landfill security
techniques will cause new environmental pollution and human health risks. The
leakage source intensity is closely related to factors such as the types and characteristics of hazardous wastes (Liu 2014; Xi 2012).
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3 Rating and Evaluation of Pollution Source Intensity …
depth and etc.), regular monitoring and environmental management, as well as
surrounding environment. For example, environmentally sensitive sites in the
surrounding area are investigated to make clear their quantity, category, distribution, impact, protective measures, geographical location, scale, position relative to
landfills, environmental functional area and surrounding land use (Hong et al. 2011;
Wang and Ji 2010; Yang et al. 2010).
The risk factors of uncontrolled landfills are preliminarily identified, including
waste hazard, potential groundwater contamination and the impact on the surrounding environment. Each risk factor is carefully divided into multiple indicators
that together form an environmental risk assessment indicator system for uncontrolled landfills (Liu 2013; Wang 2013).
Risk assessment indicators for waste hazard are listed below:
• Landfill volume: Total amount of waste landfilled (m
3 );
• Landfill period: A longer period of landfill means that the stock waste is more
stable and likely less harmful to the environment;
• Landfill type: Toxic waste, MSW, MSW mixed with construction waste, rural
solid waste, construction waste (in descending order of risk);
• Organic content: <9%, 9–16%, 16–20%, or >20% (in ascending order of risk);
• Seepage control: Two composite anti-seepage layers, single composite
anti-seepage layer, impervious clay, or natural-soil bottom layer (in ascending
order of risk);
• Leachate collection: Collection and treatment system, collection system only, or
no collection system (in ascending order of risk).
3.1.2 Characteristic Factors of HWLFs Hazards
Through data collection, on-site interview and field investigation, it is found that
typical HWLFs waste in various regions of China mainly come from the industrial
sector and are dominated by hazardous wastes containing heavy metals. Typical
hazardous wastes include fly ash, slag, and sludge containing heavy metals. Since
heavy metals are highly stable and do not decompose under the action of
microorganisms, hazardous waste containing typical heavy metals will pose persistent toxicity hazard. Moreover, the leachate generated under the external conditions such as rain or acid rain is also harmful by producing long-term
environmental hazards. Leakage sources formed due to lack of landfill security
techniques will cause new environmental pollution and human health risks. The
leakage source intensity is closely related to factors such as the types and characteristics of hazardous wastes (Liu 2014; Xi 2012).
34
3 Rating and Evaluation of Pollution Source Intensity …