*4.1.4 Landfilling and industrial waste landfills*

Landfilling is the most common, globally practiced solid waste disposal technique that involves storing large metric tons of waste in an excavated space. Landfills can store municipal, industrial, green, or hazardous wastes. According to Ref. [29] in a 2010 study, landfilling is responsible for over 30% of waste disposed of or managed in the European Union. The researchers noted that all the countries of the European Union generated about 550 kg of municipal solid waste per household in 2010 and over 400 kg of such waste was managed per person out of which almost 40% was landfilled and lesser percentage incinerated, recycled, or composted. Landfilling is practiced due to its advantages that include large volume storage, inexpensive operational procedures, and maintenance cost when compared to a disposal method such as incineration [29] but it has also been observed to pose huge environmental risks and endangerment as a result of the formation of biogas produced by the fermentation of organic matter in decomposing solid waste and leachate formed by the percolation of water through waste [3].

It is important to distinguish between an engineering landfill, whose main purpose is to ensure safety by reducing harm from accumulated wastes and allowing safe decomposition [30] and an open dumpsite (**Figure 10**). Landfills are setup and controlled by the municipal, state, or federal governments and as such are built at designated places while dumpsites on the other hand are dug by individuals, households, or communities without special consideration for setup site [30]. Landfills are covered with compact soil on regular basis to prevent offensive odors (due to biogas formation) from polluting the surrounding area; dumpsites are usually not covered with soil and so, cause air pollution [30]. Also, monitoring is an important part of any

**Figure 10.** *A typical open dumpsite in Lagos, Nigeria [3].* landfill operation as the drainage system and the liners are monitored by engineers to ensure no seepage of polluted liquid (leachate) formed within the landfill, and enters underground water; landfills are also designed with gas collection system and treatment plants for the liquid and gas produced; dumpsites, however, do not have liners or require monitoring and they are not setup with the treatment plants [30].

There are four different types of landfills that can be used for waste disposal. They include municipal solid waste, construction and demolition debris (C&DD) waste, hazardous waste (secure landfill), and green waste landfills [31]. The most common of the four types is the municipal solid waste landfill. This landfill is used to dispose of wastes from households and residential areas such as used tissues and waste cardboard. They have strict regulations with regard to disposal and operations, groundwater monitoring, landfill lining, closing practices, etc. [31]. The C&DD landfill is an industrial waste landfill used for disposing of majorly construction or demolition solid waste debris such as concrete and bricks. They may also be used to dispose other types of industrial solid waste such as asphalt, gypsum, metals, lumbers. C&DD landfills are used as material recovery facilities where wastes are sorted according to their usefulness and reusable wastes are separated from nonreusable ones [31]. Hazardous waste landfills are the most structured and regulated of all the landfill types, and this is due to the characteristic of waste disposed here. They may also be regarded as industrial waste landfill as they can be used to dispose industrial hazardous wastes such as pelletized potassium hydroxide, cyanides, oxidizers, sulfides, ethidium bromide. They store hazardous wastes in such a way as to prevent accidental discharge into the environment [31]. Lastly, green waste landfills are storage areas for organic waste materials to decompose naturally into compost. They are used to dispose biodegradable waste such as food, fruits, vegetables, garden, and other agricultural wastes [31]. A global comparison (**Figure 11**) of all the solid waste management techniques discussed above showed that the open dumpsite is readily utilized for disposal of waste. This can be attributed to the fact that dumpsites are setup any and everywhere regarded for proper site selection [16].

#### *4.1.4.1 Industrial waste landfills*

The large volume of wastes generated from manufacturing processes, especially solid wastes, are disposed at an industrial landfill. Although separate industrial landfills can be used to dispose construction, demolition wastes (C&DD landfill), and hazardous wastes, in practice, these landfills are combined in one facility as industrial waste landfill. Because of the nature of industrial wastes, landfills are designed with all the qualities and characteristics of engineering, sanitary landfill with modern design, stricter regulations, and mode of operations. Some of the design requirements of an industrial waste landfill involve provision of a compacter or compressor and plastic covering for top wastes after each operation, using an impervious double liner at landfill bottom [32], gas and leachate collection systems, groundwater quality monitoring system, etc. [33].

#### *4.1.4.2 Industrial waste landfill design structure*

One of the major activities carried out before the design of any engineering landfill is site selection. Important consideration must be given to the location of the facility to reduce operational impact on immediate surrounding and environs. Usually, tests are carried out to determine such factors as surface water vicinity, groundwater

*Perspective Chapter: Industrial Waste Landfills DOI: http://dx.doi.org/10.5772/intechopen.108787*

#### **Figure 11.**

*Global comparison of solid waste management techniques (percent) [16].*

depth, land slope, soil permeability, land elevation, soil stability, stratification and lithology faults, flood susceptibility, type of land use, urbanization and land settlement, cultural and protected site, road, airport and railway proximity, wind direction, pipe- and powerlines proximity [34]. The general layout of the landfill facility according to [9] should be made to comprise the following units as a minimum:


The engineering design involved in the construction of an industrial waste landfill requires constructing layers of different sizes in a known volume of excavated space (**Figure 12**). The smallest layer is usually located at the bottom of the landfill, while the largest layer is at the top: to prevent collapse of the surrounding area and indeed, the landfill [31]. These layers facilitate decomposition of waste materials and

**Figure 12.** *Schematic representation of a typical industrial waste landfill structure [35].*

entrapment of toxic gases released from within the landfill [31]. The different layers of an industrial waste landfill are described below.
