The development of urban areas raised the problem of the waste processing and utilization but, in the past, the technology of the waste processing was underdeveloped. In the mid-1950s, open dumps were used but this method of waste processing was ineffective. In the course of time, new approaches to the waste processing were developed. In this regard, landfills became particularly prospective but early landfills were also imperfect and needed consistent improvements. Today, landfills are the major way of the waste processing which is still imperfect but has the minimal negative impact on the environment and allows using waste to process energy. Therefore, the ideal method of the waste processing is the full recycling and processing of waste that minimizes the negative impact of solid waste on the environment.
The development of open dumps was the natural response to the accumulation of solid waste in urban areas. However, open dumps were extremely harmful for the environment. First, they covered vast territory and the territory of open dumps had to grow as the volume of waste grew. Second, open dumps covered fertile soil that led to the waste of the farmland and, more important, waste had had a negative impact on the environment. In the course of time, open dumps led to the decay of waste and emission of toxic elements which absorbed in the soil and underground water. In such a way, products of waste decay polluted the soil and potable water. Hence, the ineffectiveness of open dumps became obvious.
As open dumps became dangerous for the environment and their further development was ineffective because open dumps could not grow as fast as the volume of waste, early landfills appeared. In contrast to open dumps, which stored vast volume of waste just on the soil under the open air, landfills used the new technique of trenching, compacting and daily covering of waste with soil. In such a way, landfills could process a larger amount of waste and covered them with the soil that was supposed to minimize the negative impact of waste processing on soil and farming. However, this technology was also imperfect because waste decayed and products of decay were still absorbed in the soil and underground, potable water. Therefore, early landfills decreased the negative impact on the environment but still could not prevent the negative impact of waste and waste decay on the environment, namely on the soil and underground, potable water.
Instead, modern landfills have implemented considerable technological changes which aim at the minimization of their negative impact on the environment. In this regard, the major change refers to the protection of the soil and underground water from the decay and waste materials of landfills. Instead of simple trenching, compacting and covering waste with soil, modern landfills cover the ground of the landfill with the protection layer which prevents the emission of dangerous elements in the soil or underground potable water. Moreover, many contemporary landfills, like Puente Hills, focus on recycling of waste and production of energy. In actuality, Puente Hills landfill in California is the largest landfill in the USA. The landfill uses methane and other emissions of waste to process the waste and to produce energy.
Thus, today, the MSW involves the use of landfills which process waste and produce energy that minimizes their negative impact on the environment.