**5. Anaerobic digestion (AD) power plant: a case study of Rayong municipality**

to convince producers, suppliers and customers to produce and consume environmentallyfriendly products and packaging. Card holders will gain green points whenever they purchase eco-friendly products at participating stores which will be redeemable for special vouchers or other rewards [18]. The PM also promoted strategic planning for alternative materials to substitute for polystyrene packaging with a view to banning this form of packaging which would achieve cost reductions as well as reducing waste and also announced a feasibility study into

The increasing amount of mixed household waste has become a national problem in Thailand and elsewhere, the resolution of which may be to turn a crisis into an opportunity and reap benefits from garbage. The Thai government has instructed provincial authorities to find locations for constructing waste management facilities capable of using garbage to produce renewable energy. It is not only Thailand which lacks proper waste management systems and throughout the world peoples' attitudes to finding suitable sites to dump garbage have led to continuing conflicts and protests based on the "Not in my Backyard" (NIMBY) attitude. Therefore, it would be preferable to solve the problem by employing suitable waste management strategies as alternatives to disposal. The PM has declared that every province should build a WTE facility to convert waste to electricity which will support the country's efforts to reduce its dependence on natural gas and other fossil fuels. However, to-date, Thailand has just

Nowadays, the use of WTE technologies is gaining momentum as a favorable waste management strategy. Unquestionably, WTE seems to be a viable option for diminishing the volume of waste as well as offering the additional benefit of producing alternative energy from waste recovery [21]. Already there has been increased recovery of recyclable materials from MSW rather than continued dependence on sanitary landfilling as the primary conventional method of solid waste disposal [22]. But the benefits of energy recovery from MSW are potentially more valuable, both as an alternative energy source and for the positive environmental implications, mainly relating to the saving of non-renewable energy derived from fossil fuels [23]. WTE or energy from waste refers to any waste treatment that transforms waste resources into electricity, steam, or heat energy. These include, for example, anaerobic digestion (hereafter AD), incineration, pyrolysis, gasification, plasma arc, and RDF. WTE technologies usually reduce the volume of original waste by as much as 90%, depending on the waste composition and the type of energy derived. A waste management hierarchy generally follows the pattern of waste avoidance or reduction, reuse, recycling, recovery treatment, followed by disposal. An integrated approach to WTE that practices waste segregation and pre-treatment of waste does not by-pass the waste hierarchy but precedes or replaces the disposal step which is a more sensible approach to WTE recovery than simply burning or converting raw unsorted waste. Nonetheless, the choice of WTE technology is important and the conversion plant itself may incorporate waste pre-treatment units

the use of biodegradable plastic bags [19].

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3 WTE incinerators [19–21].

to facilitate this approach.

**4. Waste to energy (WTE) technologies**

The advantages of AD systems were set out by Spuhler [24] who noted that biogas and sludge were produced, respectively, for electricity generation and the production of fertilizer. Greenhouse gas emission can be reduced through methane recovery and efficient AD treatment systems reduce excess sludge by separating out heterogeneous organic waste, leachate, and wastewater. However, AD technologies may need to be modified to be appropriate for small and medium-scale facilities in developing countries. The high sensibility of methanogenic microorganisms need to be carefully investigated. Sulphuric compounds generated during methane production can cause erosion of equipment in AD facilities, and in order to protect AD equipment, the biogas produced may need to be significantly purified. The design and construction of AD power plants on a commercial scale needs to be under the supervision of experts, and professional operational and maintenance skills are also required to deal with fluctuations in the AD process.

Bearing in mind that Thailand is located in a tropical area and that the main economic income is derived from agricultural activities, the composition of MSW in Thailand is largely from food waste (40–60%) which has a high moisture content. Therefore, organic waste in Thailand seems to have a high potential as a raw material for producing biogas which can be converted into electricity. The case study which follows is of a biogas power plant located in Rayong municipality and includes some lessons-learned from its installation in 2004 and its operation since then.

Rayong municipality, is located in the coastal industrial zone on the eastern seaboard of Thailand. Rayong province is 179 km from Bangkok, approximately 3552 km<sup>2</sup> in area and is separated into eight districts, 58 sub-districts called Tambons in Thai and 440 villages. The population of Rayong municipality in December 2007 was 56,085: 27,110 males and 28,975 females [25].

Rayong municipality is a largely commercial city and in the late 20th Century generated increasing volumes of MSW due to the growth of the population. Between 1995 and 1997 the volume of waste grew from 57.47 tons to 63 tons per day. In 2000, the MSW contents were noted to be composed mainly of organic waste (67.77%) [26] and the bulk density of the MSW was 220 kg per m3 , as illustrated in **Table 1**.

The WTEF plant constructed in 2004 had the potential to treat 70 tons of organic waste per day. However, during 2004–2005, the organic waste fed to the AD system were separated in 2 main streams of about 12 and 3.3 tons per day of source sorted organic waste (SSOW) and mechanically-sorted organic fraction of MSW (OFMSW), respectively. The solid contents of the organic waste were 18% of total solids (TS) and 36% of volatile solids (VS) [27]. From 2006 to 2008, the organic waste collected and fed into the AD system was between 14.55 and 25.85 tons per day, with an average of 20.5 tons per day. However, this amount of organic waste was far less than the design capacity of the WTEF plant of 70 tons per day and represented only 29.3% of full capacity. A survey of the organic waste resources in Rayong municipality (**Table 2**) showed that marketplaces were the biggest source of organic waste representing 70% of the total. Other sources of organic waste were restaurants, hotels, and department stores. Nowadays, the organic waste treated in the AD plant is less than 20 tons a day.

was separated at its sources: communities, restaurants, hotels, marketplaces, and department stores in the Rayong municipal area. On the environmental aspect, the recovered CH4

the AD process that was used in electricity generation resulted in GHG reduction of about

In order to raise people's awareness of and participation in waste management, various facilities were provided and activities conducted, such as recycling banks, recycling markets, and Tung Khaw Moo which is a process in which food waste is separated and gathered before being used as animal feed. The Rayong Municipality Office approached local residents by setting up public relations teams and providing information to the community about collaborating in separating food waste from schools, households, restaurants, hotels, department stores and marketplaces. These activities need to be conducted continuously and required proper monitoring systems to be successful. However, cooperation from government departments, the administrative organization was not forthcoming and local communication was poor.

There are a number of lessons to be learned from the AD project at Rayong municipality. Firstly, the characteristics of the organic waste intended to be used should be comprehensively identified in terms of its availability, and chemical and physical characteristics. Further, the climate and also the culture, and lifestyle of the people in the area should be established and taken into consideration in assessing how much organic waste will be available. Furthermore, the small amount of organic waste produced was also a significant problem in the AD process. This might be solved by finding other sources of additional substrate such as night soil, manure, and shredded pineapple peel which could be put into the AD process to improve the biogas yield. Secondly, the facilities in the AD process should be properly designed, durable and flexible. Thirdly, AD microbial activity should be increased by means of chemicals and

**Resource The percentage of organic wastes** - Marketplaces **63.45**


Total **100**

**Table 2.** Survey of organic waste resources in Rayong municipality (modified from [28]).

Star market 41.38 Maedaeng market 6.90 Saroch's fresh-food market 4.83 Middle place night market 3.45 Clock tower night market 3.45 Tedsabaan 1 fresh-food market 3.45

Lotus 3.45 Big C 3.45

eq of total GHG emission per year [30].

http://dx.doi.org/10.5772/intechopen.74988

Sustainable Waste Management and Waste to Energy Recovery in Thailand

per year, equivalent to 7.15 Gg CO2

0.34 Gg CH4

from

227

The overall waste treated consisted of two waste streams (SSOW and OFMSW). The MSW collected is firstly processed in the front-end treatment (hereafter FET) unit then fed into the AD facilities to produce electricity and fertilizer [29]. There was a significant effect from the low amount of organic waste input and a lack of operation management which affected the loading capacity which has a maximum capacity of 70 tons of organic waste per day. The AD substrates were mostly, derived from food waste. The food waste treated at the WTE facility


**Table 1.** MSW characteristics of Rayong municipality [26].

was separated at its sources: communities, restaurants, hotels, marketplaces, and department stores in the Rayong municipal area. On the environmental aspect, the recovered CH4 from the AD process that was used in electricity generation resulted in GHG reduction of about 0.34 Gg CH4 per year, equivalent to 7.15 Gg CO2 eq of total GHG emission per year [30].

2 main streams of about 12 and 3.3 tons per day of source sorted organic waste (SSOW) and mechanically-sorted organic fraction of MSW (OFMSW), respectively. The solid contents of the organic waste were 18% of total solids (TS) and 36% of volatile solids (VS) [27]. From 2006 to 2008, the organic waste collected and fed into the AD system was between 14.55 and 25.85 tons per day, with an average of 20.5 tons per day. However, this amount of organic waste was far less than the design capacity of the WTEF plant of 70 tons per day and represented only 29.3% of full capacity. A survey of the organic waste resources in Rayong municipality (**Table 2**) showed that marketplaces were the biggest source of organic waste representing 70% of the total. Other sources of organic waste were restaurants, hotels, and department

stores. Nowadays, the organic waste treated in the AD plant is less than 20 tons a day.

**Parameter Unit, %**

Food waste 42.70 Paper 9.24 Rubber and leather 1.06 Clothes 2.25 Green waste (Wood and Leaves) 12.52 Plastic 17.13 Glass 0.74 Metal 4.26 Miscellaneous 10.1 Total **100**

Moisture content 46.70 Carbon 18.16 Hydrogen 2.18 Nitrogen 1.20 Ash 20.62 Combustible fraction 32.68 C/N ratio 15.13/1

**Composition**

226 Advances in Biofuels and Bioenergy

**Chemical characteristic**

**Table 1.** MSW characteristics of Rayong municipality [26].

The overall waste treated consisted of two waste streams (SSOW and OFMSW). The MSW collected is firstly processed in the front-end treatment (hereafter FET) unit then fed into the AD facilities to produce electricity and fertilizer [29]. There was a significant effect from the low amount of organic waste input and a lack of operation management which affected the loading capacity which has a maximum capacity of 70 tons of organic waste per day. The AD substrates were mostly, derived from food waste. The food waste treated at the WTE facility In order to raise people's awareness of and participation in waste management, various facilities were provided and activities conducted, such as recycling banks, recycling markets, and Tung Khaw Moo which is a process in which food waste is separated and gathered before being used as animal feed. The Rayong Municipality Office approached local residents by setting up public relations teams and providing information to the community about collaborating in separating food waste from schools, households, restaurants, hotels, department stores and marketplaces. These activities need to be conducted continuously and required proper monitoring systems to be successful. However, cooperation from government departments, the administrative organization was not forthcoming and local communication was poor.

There are a number of lessons to be learned from the AD project at Rayong municipality. Firstly, the characteristics of the organic waste intended to be used should be comprehensively identified in terms of its availability, and chemical and physical characteristics. Further, the climate and also the culture, and lifestyle of the people in the area should be established and taken into consideration in assessing how much organic waste will be available. Furthermore, the small amount of organic waste produced was also a significant problem in the AD process. This might be solved by finding other sources of additional substrate such as night soil, manure, and shredded pineapple peel which could be put into the AD process to improve the biogas yield. Secondly, the facilities in the AD process should be properly designed, durable and flexible. Thirdly, AD microbial activity should be increased by means of chemicals and


**Table 2.** Survey of organic waste resources in Rayong municipality (modified from [28]).

adjustment or improvement of the anaerobic microbial activity of enzymes. Finally, the feasibility of investing in this kind of project should be carefully considered taking into consideration social awareness and people's willingness to participate since both are essential for the sustainable development of such projects.
