Landfil Safety Plan: a methodology to guarantee safe waste management

摘要

Municipal solid waste landfills are frequently identified as sanitary structures from where environmental and public health impacts can arise. In the last decades improvements in landfill design schemes, construction guidelines, and operational monitoring methodologies have been established in order to minimise hazards and hazardous events aiming to high level of confidence for the neighbouring populations.Nonetheless, technological deficiencies, emergent chemicals and microbial pathogens present in municipal (household and industrial) solid waste as well as our scientific understanding in respect to their impact and persistence in the environment recommend special attention to implement effective methodologies for their control.Major concerns in construction and in operation are related to the protection against emissions from landfills, namely leachate and gas. Potential environmental impacts of these emissions greatly depend on the type of waste being landfilled, the hydrogeochemical characteristics of the site and the technology implemented. Frequently referred environmental impacts of a landfill are: methane emissions contributing for greenhouse effects; toxic VOCs and odours in the air of the proximity areas; animals (birds, rodents, insects, etc.) that can represent disease vectors; wind-blown litter and dust; explosion and fire damage; vegetation damage; surface and groundwater pollution.A great variety of landfill concepts and practices from modern landfill technology to unengineered dumps receiving all type of waste can be found worldwide. In this respect, the situation in developing countries is of great concern not only for the environment impacts point of view, but essentially in respect of public health risks for a significant amount of population. Even the most developed countries are increasingly recognising difficulties with surveillance and safety of landfills.Recognising these limitations a more effective approach for safeguarding public health and environmental impacts is proposed in this paper. Recent experiences and approaches in Water Safety Plans, give the opening for a novel concept of landfill safety plan based on effective risk assessment and risk management approaches in landfill design and operation.Landfill performance control has currently been based on detection of pathogens and toxic concentrations of chemicals by means of monitoring programs and compliance with national or international guidelines and standards, relying mainly on indicator bacteria and chemicals maximum concentration levels. However, this methodology is often slow, complex and costly. Even for sophisticated and well-operated systems these monitoring schemes have proved to be inefficient in preventing waterborne diseases and environmental impacts. From this evidence we can conclude that this testing methodology is a reactive rather than preventive way to demonstrate confidence in landfill practice. This justifies the need for the formulation of a new approach in landfill control based on understanding of system vulnerability for contamination and on preventive means and actions necessary to guarantee the safety of these sanitary structures. For that reason landfill safety plan is a new concept for risk assessment and risk management throughout the phases of initial design, monitoring, closure and post-closure of landfills. This approach includes risks identification and priorisation, and the introduction of control points and control measures that serve to eliminate or minimize those risks. This paper describes an overview of a framework for developing a landfill safety plan that can be readily used by technological advanced as well as traditional landfills.