**1. Introduction**

 The traditional consideration of waste as a pollution has progressively shifted toward a new perspective, in which waste is regarded as a resource that could support societies to become more sustainable [1].

LCA as a tool to analyze waste management systems appeared in the early 1990s.

 A number of models for LCA of waste management have been developed, and some of these models are commercially available, while others are affordable only to researchers [2]. All models are developed within the framework of LCA of waste management, and most models also include some kind of economic accounting [2]. Moreover, in [2], a summary of key features of waste management LCA models is presented. Among them are:

• *Integrated waste management-2 (IWM-2)*, updated version of the IWM-1, released by Procter and Gamble in 1995. The IWM-2 and IWM-1 have been used in many case studies in Europe, North and South America and Australia.


*Life Cycle Inventory (LCI) Modeling of Municipal Solid Waste (MSW) Management Systems… DOI: http://dx.doi.org/10.5772/intechopen.84347* 

**Figure 1.**  *Components of a life cycle assessment (LCA) according to International Organization for Standardization (Source: [9]).* 

Life cycle assessment (LCA) is one of the environmental management techniques, which aims to assess potential hazards to the environment of products, processes or entire systems. LCA as a tool to analyze waste management systems appeared in the early 1990s. It is worth noting that among researchers and decision makers, the use of LCA to analyze and develop waste management strategies has increased considerably over the last few years [2]. Moreover, LCA is a useful framework for assessing environmental performances [3]. The role of LCA has been increasing as it was proposed in many EU and Polish official documents [4]. Currently the LCA methodology is more and more frequently used as a tool for evaluating the environmental performance of products or services [5].

The LCA description is based on the ISO standard series 14040-14044 (2006) [6] and the guidelines provided by Guinée [7]. According to ISO, LCA is used for hot spot analysis, product or process improvement, comparative assertion, marketing and environmental policy.

In accordance with the ISO 14040 (2006) [7] standard, describing the principles and framework, LCA consists of the four phases [8] as illustrated in **Figure 1** [9]. Life cycle inventory (LCI), the second valuable step of LCA, is the most effective quantitative environmental assessment tool [10].
