Characteristics and management of domestic waste in a rural area of the Tibetan Plateau

Abstract

In the rural area of the Tibetan Plateau (RATP), the characteristics of domestic waste, people’s environmental awareness, people’s willingness to pay and their influence factors were firstly studied by questionnaires, field samplings and laboratory tests. The results showed that, in the RATP, the generation of domestic waste was 85 g•d-1 per capita and it was mainly composed of plastics, inert waste, kitchen waste, glass and paper. The waste bulk density, moisture content, ash, combustible and low calorific value were 65 kg•m-3, 19.25%, 44.90%, 35.85% and 10,520 kJ•kg-1 respectively. These characteristics are influenced by income sources and geographical position to some extent. Classified collection should be promoted widely on the household and the village basis. Compost, fermentation, landfill, bioreactor landfill and semi-aerobic landfill have been approved as effective techniques to treat domestic waste, except incineration. The distance of 50–800 m between each collection facility and the disposal fee of around $0.8 per month per household are suggested. For suburbs or large population villages, it’s better to treat domestic waste by the centralized way. But for the remote rural areas, a decentralized way is proposed. Significantly, the educational and economic influence should be considered into an effective domestic waste management program.

Implications: The current situatio n of the environment in the rural areas of the Tibetan Plateau (RATP) was surveyed. There, the generation of organics and moisture of domestic waste were low but ash, recyclables, and combustibles were high. People’s knowledge of domestic waste was absent but their participation in management was strong. Based on the current situation, compost, fermentation, and landfill were effective but incineration was inappropriate. Also, a localized mini landfill for a cluster of villages and or settlements was the best method there.

Introduction

The Tibetan Plateau is a large tectonic geomorphological region in central Asia with an average altitude of 4,000 m and a total area of 2,250,000 km² that contains a population of 10,214,200 (Chen and Shen, 2000). Due to its high altitude, low atmospheric pressure, low oxygen content, and low temperature, the environment is very sensitive and fragile. Moreover, it is lacking in preventative and self-renewal capability (Jiang et al., 2009). The Tibetan Plateau is also the source of the Yellow, Yangtze, and Lantsang rivers, and its water reserves comprise one-third of the total reserves of China. Therefore, the environmental health of the Tibetan Plateau is of significant concern to China and other Southeast Asian nations.

Economic development and changes in lifestyles in the Tibetan Plateau have resulted in increasing consumption of packaged and processed goods, including food and other items, in recent decades, especially since opening of the Qinghai–Tibet railway. Dan and Han (2012) reported that the amount of municipal solid waste (MSW) in Lhasa increased rapidly to 600 t d⁻¹ in 2010. The MSW in this region has characteristics such as a high per-capita discharge, low water content, high ash content, high lower calorific value, and a high percentage of recyclable matter (Dan and Han, 2012). Moreover, it has been predicted that MSW generation in Tibet will reach 4,942 t d⁻¹ in 2020 (Jiang et al., 2009). Therefore, alternative methods of MSW management have been studied (Dang and Ouyang, 2009) and use of semi-aerobic landfilling to treat MSW in Tibet has been investigated (Yang and Zha, 2008). However, no studies of the characteristics or management of domestic waste in rural areas of the Tibetan Plateau (RATP) have been conducted to date, even though the rural population makes up more than 60% of the total population. Notably, solid waste management in the RATP is becoming a major concern. The RATP is also characterized by a shortage of appropriate infrastructure and formally organized solid waste management, which has resulted in increasing problems related to domestic waste, including impacts on human health and decreasing aesthetic values of rural villages and their surroundings. Moreover, pollution has been influencing the quality and security of water in the region (Zhao, 2009). Therefore, it is essential to investigate domestic waste treatment, the characteristics of domestic waste, local residents’ knowledge of domestic waste, their willingness to pay and participate in domestic waste management, the influence factors of the characteristics, and the factors influencing people’s awareness of the RATP.

Materials and Methods

Survey design

This investigation was carried out in five villages located in southern Tibet and northwest Sichuan province (Figure 1). These villages were selected according to their locations, income sources, topography, and distance from the nearest towns or cities (Table 1).

Table 1. Overviews of the investigated villages.

Villages	Location	Income sources	Topography	Distance from city
Dajielin	Zalang, Shannan, Tibet	Handicraft making	In the valley of middle reaches of Yalutsangpo River	2 km
Jina	Gongga, Shannan, Tibet	Crop farming and livestock breeding		19 km
Baidui	Qushui, Lhasa, Tibet			34 km
Yang shan	Jiuzaigou, Aba, Sichuan	Livestock breeding and tourism	At the foot of a mountain	40 km
Baisa	Maerkang, Aba, Sichuan	Migrant or local working	On the hillside of mountains	40 km

Figure 1. Geographical position of the investigated villages.

About 10 rural households were randomly selected in each village to survey by an interview questionnaire. Overall, 51 households were interviewed and investigated in August 2012. Questionnaires were designed to obtain the following information:

1. The socioeconomic characteristics of the households.

2. The present environmental pollution and current situation of the management, collection, transfer, treatment, and disposal of domestic waste.

3. Residents’ knowledge regarding domestic waste pollution, as well as hazardous and recyclable domestic waste.

4. Residents’ mode of domestic waste collection and treatment.

5. Residents’ willingness to pay for domestic waste services and participate in domestic waste management.

Experimental design

A garbage bag was provided for each interviewed household to collect all of the domestic waste discharged over 2 days. The mixed waste of each household was then collected and weighed by researchers, after which all domestic waste discharged by interviewed households within a village was collected and mixed. The bulk density was tested, after which it was sorted, the sorted components were weighed, and the composition of domestic waste in each village was calculated. Finally, 1 kg of domestic waste was sampled as the proportion of wet component in each village and brought back to the laboratory for testing and analysis.

Before testing, the samples were prepared. First, samples of each component of domestic waste collected in every village were dried, after which they were crushed and stored.

The bulk density and the composition of wet mix waste were sampled according to the Sampling and Analysis Methods for Domestic Waste (CJ/T 313-2009) promulgated by the Ministry of Housing and Urban–Rural Development of the People’s Republic of China. The characteristics of each sample, including the moisture content, combustible content, and ash, were tested. Since the kitchen waste, wood, and ash in the Tibetan Plateau are different from other areas due to its specific climate and culture, the calorific values of those fractions were tested with a calorimeter (IKA C 2000), and the calorific values of other components were cited from typical values shown in the aforementioned standard. Finally, the characteristics of the domestic waste were calculated as the proportion of the composition.

The domestic waste generation was analyzed on a household basis, while other characteristics were analyzed on a village basis using eq 1. Analyses were conducted using Microsoft Excel 2007 and SPSS 19.0:

(1)

where y is the data for the Tibetan Plateau; x is the data on a household or village basis; and f is the calculation formula or statistic function.

Results and Discussion

Backgrounds of investigated individuals and households

Table 2 presents the socioeconomic characteristics of the investigated people and households. Most of the interviewees were middle-aged because young people had migrated. As a result, only 29.4% of the interviewees were literate and had a junior education or higher. In addition, the income of investigated households was relatively low compared to the average in China. The primary sources of income were farming, breeding livestock, and migrant or local employment. Overall, 94.1% of investigated households had an income of less than $4,888 per year.

Table 2. Socioeconomic characteristics of the investigated households.

Interviewees’ age (years)	≤30	30–50	50–70	≥70
Proportion (%)	21.6	45.1	27.4	5.9
Interviewees’ educational level	Illiteracy	Primary	Junior	Senior	Higher
Proportion (%)	21.6	49.0	13.7	5.9	9.8
Annual income ($)	≤814.6	814.6–1,629.2	1,629.2–4887.6	4887.6–8,145.0	≥8,145.0
Proportion (%)	33.3	21.6	39.2	5.9	0
Main source of income	Corp farming	Livestock breeding	Both corp farming and livestock breeding	Migrant or local working	Service or others^a
Proportion (%)^c	9.8	7.8	37.3	27.5	23.5
Livestock	Cattle	Pigs	Poultry	Dogs	Others^b
Proportion (%)^c	86.3	66.7	66.7	51.0	29.5
Energy in daily life	Firewood	Coal	Electricity	Biogas or natural gas	Cow dung
Proportion (%)^c	100.0	2.0	100.0	33.3	58.8

Notes: ^aIncluding catering, tourism, retail and handicraft making.

^bIncluding sheep and horse.

^cMultiple choice.

Current situation

In the RATP, a special municipality for managing and controlling the environmental pollution has not been set up below the county level to date. Additionally, areas suffer from a shortage of infrastructure, appropriate legislation, and funds for environmental control, especially in remote areas. As a result, solid waste services including collection, transfer, and disposal are rare. Additionally, when present, the services are commonly reduced to collection and simple disposal, which are mainly organized and conducted by the local village committee or town government. A significant portion of the population does not have access to a waste collection service, and only a fraction of generated waste is actually collected. The final disposal of domestic waste was commonly by burning (70.59%), random dumping into local rivers or open dumpsites (33.33%), collecting in simple landfills (19.61%), and composting for organic fertilizer (11.76%). These simple disposals have led to serious solid waste pollution and water pollution (Figure 2).

Figure 2. Kinds of environmental pollution in the investigated villages.

Characteristics of domestic waste

Generation

The average per-capita generation of domestic waste in the RATP was 85 g d⁻¹, although it fluctuated greatly from 39 to 156 g d⁻¹ among villages. As shown in Table 3, this level is much lower than that of urban areas of the Tibetan Plateau (Dan and Han, 2012), Italian rural areas (1616 g d⁻¹ per capita) (Passarini, et al., 2011), and Iranian rural areas (Abduli, et al., 2008).

Table 3. Comparison on the physical characteristics of domestic waste in the RATP and others.

Physical characteristics		Rural area of the Tibetan Plateau	Urban area of Lhasa^[3]	Rural area of Fiji^[16]	Rural area of Iran^[8]
Generation (g·d^−1 per capita)		85	1370	/	646
Composition (%)	Plastics	21.34	14.84	7.50	13.34
	Inert waste	23.25^a	22.83^a	9.40^b	11.70^c
	Kitchen waste	16.25	20.45	69.90	42.49
	Glass	14.94	4.73	1.00	5.89
	Paper	11.29	23.74	6.40	8.77
	Wood	6.23	2.76	/	6.90
	Textiles and leather	4.71	4.50	1.70	4.83
	Metals	1.38	5.12	4.10	6.08
	Others	0.61^d	1.03^d	/	/

Notes: ^aIncluding ash, dirt, bricks, and ceramic tiles.

^bIncluding ash, dirt, wood, bricks, and hazardous waste.

^cIncluding construction and demolition.

^dIncluding batteries, expired medicine and other indistinguishable waste.

Physical characteristics

The results of the waste composition analysis are shown in Table 3. The prevailing composition of domestic waste (in wet weight percentages) was plastics, inert waste, kitchen waste, glass, and paper, and their total proportion reached 83.95%. The percentage of recyclable waste including plastics, glass, paper, and metals was up to 48.95%; however, the proportion of biodegradable waste was only 22.48%. There was very little “other” waste, which consisted of batteries, expired medicine, and other indistinguishable waste.

There was a similar percentage of inert waste, kitchen waste, textiles, and other waste in rural and urban areas of the Tibetan Plateau. The level of plastics, glass, and wood was much larger but the content of paper and metals was obviously smaller in the RATP. Moreover, when compared to rural areas of other countries, the domestic waste in the RATP has some typical features, including an abundance of recyclable waste and a shortage of kitchen waste. These typical features were due to differences in residents’ habits and customs, recyclable activities, and climate among areas.

Owing to the large portion of plastic and paper, the domestic waste of the RATP was very light. The average bulk density was 65 kg m⁻³, with a range of 41 kg m⁻³ to 112 kg m⁻³. This value is obviously lower than in Lhasa (300 kg m⁻³) (Dan and Han, 2012), which results in a good compressibility.

Chemical characteristics

The chemical characteristics of each component of domestic waste are shown in Table 4. The moisture, ash, and combustible contents of domestic waste were 19.25%, 44.90%, and 35.85%, respectively, which were similar to those of MSW in Lhasa (24%, 38% and 38%) (Dan and Han, 2012). Based on the proportion of each component and its chemical characteristics, the moisture of domestic waste was primarily derived from kitchen waste, the ash was mainly derived from inert waste, glass, and kitchen waste, and the combustible fraction was derived from paper and plastics.

Table 4. Chemical characteristics of each component of domestic waste.

Composition	Moisture content (%)	Ash content (%)	Combustible (%)	Gross calorific value (kJ kg^−1)
Kitchen waste	45.50	31.59	22.91	4,650^a/12,677^c
Paper	22.82	14.62	62.56	16,600^a
Plastics	17.85	12.51	69.64	32,570^a
Textiles and leather	14.22	1.60	84.18	17,450^a
Wood	32.34	31.72	35.94	18,610^a /12,002^c
Inert waste^b	13.68	75.58	10.74	6,980^a /4,344^c
Glass	0.10	98.00^a	1.90	140^a
Metals	0.00	98.00^a	2.00	700^a

Notes: ^aThe typical value from the “Sampling and Analysis Methods for Domestic Waste” (CJ/T 313-2009).

^bIncluding ash, dirt, bricks and ceramic tiles

^cTest value with a calorimeter.

In the RATP, the lower calorific value of domestic waste was very high, reaching 10,520 kJ kg⁻¹. This value was obviously higher than that of the urban area of the Tibetan Plateau (7,877 kJ kg⁻¹) (Dan and Han, 2012) and the rural area of Iran (2,414–8,916 kJ kg⁻¹) (Abduli, et al., 2008). This is due to the high content of combustible material and low content of moisture in the domestic waste of the RATP.

Factors influencing domestic waste characteristics

Based on the statistics of 51 households, Table 5 shows the influence of different factors on characteristics of domestic waste in the RATP, including income sources and geographical position of investigated households. Based on the Kruskal–Wallis test and analysis of variance (ANOVA), the characteristics of domestic waste from Tibet and Sichuan did not differ significantly. Moreover, there was no significant difference among different income sources such as crop farming or livestock breeding, migrant or local working, and service or business.

Table 5. Analysis of influence factors on the characteristics of domestic waste.

		Influence factors
		Income sources			Geographical position
Characteristics		Crop farming or livestock breeding	Migrant or local working	Service or business	Tibet	Sichuan
Generation (g·d^−1 per capita)		58	137	79	89	79
Composition (%)	Kitchen waste	15.85	16.55	21.23	12.77	21.64
	Paper	9.29	11.80	13.76	10.73	12.16
	Plastics	17.93	20.49	26.87	20.77	22.20
	Textiles and leather	1.49	4.75	6.59	5.91	2.84
	Wood and bamboo	8.71	0.00	4.54	10.26	0.00
	Ash and dirt	34.18	0.00	7.83	33.12	0.00
	Bricks and ceramic tiles	0.78	8.01	1.98	2.04	4.78
	Glass	10.79	36.50	14.71	1.83	35.25
	Metals	0.29	1.90	1.83	1.54	1.13
	Others	0.68	0.00	0.66	1.02	0.00
Bulk density (kg·m^−3)		84	75	49	59	74
Moisture (%)		23.57	5.04	23.86	18.75	20.41
Ash (%)		52.32	50.51	37.37	42.28	50.34
Combustible (%)		24.10	44.44	38.76	38.98	29.25
Lower calorific value (kJ·kg^−1)		8256	11490	12240	11228	9418
Mean rank		24.75	23.56	25.19	16.88	16.12
Significance of Kruskal–Wallis test		0.944			0.821
Significance of ANOVA		0.962			0.903

As shown in Table 5, the content of ash, dirt, and wood in the rural portion of Tibet is much higher than in Sichuan. This is mainly due to the difference in the energy resource structure. With the exception of electricity, cow dung and firewood were the most important energy resources in the investigated households in the rural area of Tibet. However, in Sichuan Province, no investigated households used cow dung as an energy resource because of the different climate and people’s different habits and customs. Conversely, the content of glass in rural Tibet is obviously lower than in Sichuan.

The income sources of the investigated households primarily influence the characteristics of domestic waste on the composition because of their different productive and consumptive activities, habits, and customs. Therefore, domestic waste collected from households whose income primarily depends on service or business contains a higher percentage of paper, plastics, kitchen waste, and textiles and leather than that of other households. This typical composition results in the highest lower calorific value. Moreover, the domestic waste collected from households whose income primarily depends on crop farming or livestock breeding has a higher percentage of ash, dirt, and wood because most of them used firewood as an energy resource. As a result, its bulk density was highest.

Based on the mean ranks of different income sources, the characteristics of domestic waste in households whose income primarily depends on migrant or local workers are very different from those of other households. Specifically, in such households, electricity was the dominant energy source and some of the households used biogas or natural gas. Accordingly, little ash, dirt, wood, or bamboo was found in the domestic waste. However, a large amount of glass was discharged in their domestic waste. Both more discharged glass and smaller number of family members lead to the highest generation of domestic waste per capita in those households.

Although there are no significant differences among influence factors, the characteristics of domestic waste were influenced by these factors to a certain extent. The differences in chemical and physical characteristics are mainly due to the energy resource, recycling activity, and residents’ productive and consumptive activities, habits, and customs.

Environmental awareness

Knowledge of domestic waste

Table 6 shows the residents’ knowledge of pollution, toxicity, and recyclable characteristics of domestic waste in the investigated villages.

Table 6. People’s knowledge of domestic waste and the analysis of its influence factors.

		Interviewees’ proportion of awareness (%)
			Influence factors
			Education			Revenue (dollars per year)
People’s knowledge of domestic waste		Tibetan Plateau	Illiteracy	Primary education	Junior school education and above	R < 814.6	814.6 ≤ R < 1,629.2	R ≥ 1,629.2
Pollution	Water pollution	66.67	63.64	64.00	66.67	82.35	81.82	43.48
	Amenity and landscape degradation	25.49	36.36	36.00	33.33	11.76	27.27	56.52
	Air pollution	23.53	9.09	24.00	40.00	17.65	27.27	30.43
	Land occupation and contamination	17.65	36.36	16.00	26.67	11.76	45.45	21.74
	Sanitary deterioration	15.69	18.18	28.00	40.00	17.65	36.36	34.78
Hazardous waste	Pesticide bottles	92.16	100.00	100.00	86.67	100.00	100.00	91.30
	Expired medicine	50.98	54.55	56.00	66.67	70.59	63.64	47.83
	Batteries	27.45	18.18	20.00	53.33	11.76	18.18	47.83
	Chemical packaging in daily life	15.69	9.09	16.00	20.00	0.00	9.09	30.43
	Fluorescent lamp tubes	3.92	9.09	4.00	0.00	0.00	9.09	4.35
Recyclable waste	Metals	88.24	90.91	88.00	73.33	94.12	90.91	82.61
	Plastics	62.75	63.64	60.00	53.33	58.82	63.64	56.52
	Paper	54.90	63.64	36.00	86.67	35.29	45.45	73.91
	Glass	37.25	27.27	44.00	33.33	17.65	18.18	60.87
	Textiles	1.96	0.00	0.00	13.33	0.00	9.09	0.00
Mean rank		/	21.77	21.80	25.43	19.60	23.90	25.50
Significance of Kruskal–Wallis test		/	0.679			0.444
Significance of ANOVA		/	0.779			0.648

Domestic waste impacts human health as well as the environment. Water pollution owing to domestic waste led to the most concern among local villagers, with 66.67% of interviewees thinking domestic waste could cause water pollution. This proportion was about 2.6–4.2 times that for other pollutants caused by discharged domestic waste. However, no residents thought that domestic waste could contribute to groundwater pollution, which was likely because it is difficult to detect and perceive.

More than 90% of interviewees understood that pesticides were toxic, but only half of the interviewees were aware of the toxicity of expired medicine. Residents generally did not know about other hazardous waste generated by their households, such as batteries, chemical packaging, and fluorescent lamp tubes.

Recyclable domestic waste including metals, paper, plastic, and plastic film were well known. However, glass and especially textiles were not commonly known to be recycled, likely because few recyclers were willing to recover them.

Factors influencing people’s knowledge of domestic waste

Based on the results of the KruskalºWallis test and one-way analysis of variance (ANOVA; Table 6), although there was no significant difference in knowledge of pollution or the hazardous and recyclable characteristics of domestic waste among individuals of different educational levels, the mean rank of the Kruskal–Wallis test showed that people with higher levels of education are more environmentally aware than those with lower education. Moreover, the mean rank increases with increasing revenue. These findings indicate that family income level can positively influence knowledge regarding domestic waste because income is generally correlated with higher education.

As expected, members of the more educated group were more likely to sort their waste, had a greater requirement for treating domestic waste, and were more likely to treat domestic waste collectively by village committee (Table 7). Indeed, there was a logarithmic correlation between educational years and the proportion of interviewees who thought it was necessary to treat domestic waste:

Table 7. Influence of education on waste sorting collection and treatment.

	Interviewees’ proportion (%)
	Education			Revenue (dollars per year)
Items	Illiteracy	Primary education	Junior school education and above	R < 814.6	814.6 ≤ R < 1,629.2	R ≥ 1,629.2
People’s willingness to sort domestic waste	63.64	92.00	80.00	88.24	90.91	73.91
People’s agreement on the necessity of domestic waste treatment	54.55	88.00	100.00	82.35	100.00	78.26
People’s agreement on the collective treatment of domestic waste	45.45	64.00	80.00	76.47	81.82	47.83

where y is the proportion of interviewees and x is the educational years.

In general, literacy is low in the RATP, and environmental education is absent from the primary education program. Therefore, an extensive environmental education should be provided to enhance environmental understanding in the RATP.

Willingness to pay for domestic waste services

Willingness to pay

As shown in Table 8, as the price paid to residents for recycling increases, their willingness to sort domestic waste becomes strong. After the recycling price exceeds $0.3 per kilogram, more than two-thirds of interviewees were willing to sort recyclable waste. Additionally, 82.35% of interviewees accepted the disposal fee with less than $0.80 per month per household. If the disposal fee, the collection facility fee, the disposal facility fee, and the price of organic fertilizer are more than $0.80 per month per household, $1.60 per household, $16.3 per household, and $0.08 per kilogram respectively, more than half of people may refuse to pay.

Table 8. People’s willingness to pay and the analysis of its influence factors.

		Interviewees’ proportion of willingness to sort, to pay or to buy (%)
			Influence factors
			Education			Revenue (dollars per year)
Price or fee		Tibetan Plateau	Illiteracy	Primary education	Junior school education and above	R < 814.6	814.6 ≤ R < 1,629.2	R ≥ 1,629.2
Price of recyclable waste (dollars per kilogram)	P < 0.16	27.45	18.18	36.00	20.00	23.53	0.00	43.48
	0.16 ≤ P < 0.32	37.25	27.27	40.00	40.00	23.53	36.36	47.83
	0.32 ≤ P < 0.65	66.66	54.54	72.00	66.67	64.71	81.81	60.87
	P ≥ 0.65	72.54	54.54	84.00	66.67	82.36	81.81	60.87
Disposal fee (dollars per month per household)	0.16 ≤ F < 0.81	82.35	81.82	84.00	80.00	94.12	72.72	78.26
	0.81 ≤ F < 1.63	39.21	27.27	36.00	53.33	29.41	54.54	39.13
	1.63 ≤ F < 2.44	19.60	9.09	24.00	20.00	23.53	18.18	17.39
	2.44 ≤ F < 3.26	9.80	9.09	8.00	13.33	17.65	9.09	4.35
	3.26 ≤ F < 4.89	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Collection facility fee (dollars per household)	F < 1.63	90.19	81.81	88.00	93.34	100.00	100.00	73.91
	1.63 ≤ F < 8.15	39.21	36.36	28.00	53.34	23.53	63.64	34.78
	8.15 ≤ F < 16.29	1.96	0.00	0.00	6.67	0.00	9.09	0.00
	F ≥ 16.29	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Disposal facility fee (dollars per household)	F < 16.29	64.71	81.82	60.00	60.00	70.59	54.54	65.22
	16.29 ≤ F < 48.88	23.53	27.27	16.00	33.33	23.53	18.18	26.09
	F ≥ 48.88	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Organic fertilizer price (dollars per kilogram)	P < 0.08	80.39	81.81	80.00	86.67	88.23	90.90	78.26
	0.08 ≤ P < 1.63	35.29	45.45	24.00	46.67	35.29	63.63	26.09
	1.63 ≤ P < 0.32	5.88	9.09	4.00	6.67	5.88	18.18	4.35
	0.32 ≤ P < 0.65	1.96	0.00	0.00	6.67	0.00	9.09	0.00
	P ≥ 0.65	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Mean rank		/	31.91	33.48	35.11	33.75	35.02	31.71
Significance of Kruskal–Wallis test		/	0.856			0.845
Significance of ANOVA		/	0.851			0.816

Factors influencing willingness to pay

As shown in Table 8, there was no significant difference in willingness to pay for domestic waste services among individuals of different education or economic levels. This was likely because overall income in the region was so low that there were no obvious differences in income. However, the mean rank increases with increasing educational levels, which means that improving educational level can enhance willingness to pay for domestic waste service. It should be noted that there was a significant difference in willingness to pay among different levels of payment (p < .001), with a logarithmic decrease occurring with increasing payment.

As shown in Table 7, the lower income group tended to recycle more waste, which was similar to the results of a previous study (Chung and Poon, 2001). The correlation coefficient between annual income per household and the proportion of interviewees who are willing to sort waste was –0.94. This was likely in response to the monetary reward rather than environmentally friendly behavior (Chung and Poon, 2001). In the last decade, different authors have stated that the implementation and development of waste management programs that ignore social aspects are doomed to fail (Morrissey and Browne, 2004; Henry et al., 2009). Therefore, an economic and educational element should be considered in any organized waste management plan implemented in the region.

Waste management

Collection and transfer

Waste collection strategies represent a major issue in an efficient waste management system since they can significantly affect recycling targets (Passarini et al., 2011; Chowdhury, 2009; De Oliveira Simonetto and Borenstein, 2009). It is notable that there is in the RATP an abundance of recyclable domestic waste, such as beer bottles, soft drink bottles, and cardboard, that can be recycled and reused. Although many people cannot identify the recyclable waste, some recyclers have driven regularly to the villages, where they were able to easily collect high-value items of recyclable waste. Moreover, 84.31% of interviewees were willing to sort waste that could be sold to the recyclers, and the economic driving force of classified collection was very high for local residents (Table 8). Although recycling of waste is a new concept for rural residents, it has been readily adopted by most rural communities without too much need for raising awareness (Chung and Poon, 2001). Moreover, even though there has been some social, economic, and material basis to encourage people to sort domestic waste in the RATP, source separation is not common in the region. Therefore, policymakers should not only focus on whether members of the public know how to separate waste, but also on methods to motivate them to separate waste for individual and social benefit and to maintain an effective market for recyclables. For example, many recyclers or recycling companies should be encouraged to collect recyclable waste in the RATP, especially in remote villages, because the cost of collection and transportation is too high for recyclers or recycling companies to gain any benefit.

The results of the study also indicated that the majority of interviewees (up to 98.04%) were willing to dump their domestic waste into collection facilities. However, infrastructure such as transportation, communications, and environmental protection facilities is still poor in most villages. Especially, environmental protection facilities are so poor that they have restrained the waste from recycling. Several scholars have recently suggested that intermunicipal cooperation should be a viable alternative to local privatization, especially in smaller rural municipalities with a lower number of potential outside contractors (Warner and Hefetz, 2003; Bel and Mur, 2009). Thus, it is very important that the government enhance construction and investment in infrastructure and the intermunicipal cooperation in the RATP. Additionally, distance required to dump domestic waste must be considered when constructing any collection facilities, because the relationship between willingness to use facilities and their distance showed a negative logarithmic correlation (Figure 3). Overall, the results indicated that a distance of 50–800 m is appropriate, with 88.24% of interviewees being willing to dump their domestic waste into collection facilities within this distance.

Figure 3. Relationship between people’s willingness and the dumping distance.

Treatment and disposal

Overall, 62.75% of interviewees reported they would rather collectively treat domestic waste by village committee than by themselves. This means that in rural areas the support and the popularity of centralized treatment for domestic waste are even more prominent than for decentralized treatment.

In some developed countries, marketing activities of centralized treatment of waste have been extremely successful, such as rural waste management in Aragon, Spain (Bel and Mur, 2009). However, in most developing countries, the treatment of domestic waste is still primitive. Similar to Fiji (Padma et al., 2007) and India (Gowda et al., 1995), burning, burying, and dumping of wastes are the most common disposal methods in the RATP. Currently, only 11.76% of investigated households discharged unsorted domestic waste to simple landfills. Additionally, standard landfills are unavailable in the RATP because of their poor economic performance. However, given the extremely dry climate, the very low moisture of domestic waste, and the low content of kitchen waste, it is possible to build a relatively simplified landfill with a liner system, landfill gas venting system, and capping system among some neighboring villages or towns. Notably, leachate recirculation can maintain an optimum moisture condition of at least 31% volumetric moisture content (Yuen et al., 2001). Transfer stations in which waste can be sorted and be transferred to neighboring landfills need to be established in every village. Additionally, special clearances must be obtained from local governments or municipalities if hazardous waste or any contaminated soil is to be disposed of at the landfill.

Although the percentage of organic matter is relatively low and compositing is considered an extra daily chore, it has been practiced in the region for a long time. If a large amount of organic waste could be collected from the villages to compost or ferment, the organic fertilizer made from those processes would have a wide market value in the RATP. Indeed, 84.31% of interviewees were willing to utilize organic fertilizer.

Inert waste such as ash and dirt can be returned to farmland, while bricks and ceramic tiles can stored in a special site or used as paving materials. Both the bioreactor landfill (Li et al., 2011) and the semi-aerobic landfill (Yang and Zha, 2008) have been approved as effective techniques to treat domestic waste in rural areas or on the Tibetan Plateau. However, incineration is not considered a suitable method of treating domestic waste in the RATP because of its expensive cost, difficulty with gas control, and shortage of technologists and supervisors. Accordingly, incineration has the potential to exert negative effects on air quality and people’s health in the RATP.

Management

According to the latest demographics and survey results, it is estimated that rural residents in the Tibetan Plateau would produce more than 190,000 tons of domestic waste per year, which would be discharged freely on the plateau. In rural areas, people primarily perceive pollution based on their senses; hence, the visual impact of such waste will be seen as the main reason for domestic waste management practices in households. Indeed, more than 80% of interviewees thought that the domestic waste needed to be treated. Moreover, they expected that waste services would occur regularly and that domestic waste would be managed appropriately.

Generally, the best waste management practices should be based on the principles of reducing, recycling, and reusing waste. Some activities in keeping with these principles, such as composting household waste, establishment of recycling centers, and engagement of a waste removal company to remove domestic waste from the area, can be promoted at the village or the community level.

Rural waste management options are limited in the RATP because of the small population size, geographical distribution of households or villages, and limited resources. Based on a previous case study (Padma et al., 2007) and the current situation of the RATP, options for rural domestic waste management are as follows:

1. A partially subsidized rural–urban tandem residual waste collection and disposal system.

2. A localized transfer station linked to an existing landfill within the economic transfer distance.

3. A localized mini landfill for a cluster of villages and or settlements.

4. A small bioreactor for a remote village, settlement or a few neighboring households.

Regardless of which system is selected, it is important to ensure financial viability when designing the system. Accordingly, the following practical considerations are important:

1. Collection and transfer of residual wastes and recyclable material into waste bins under the rural–urban tandem system, transfer stations, or mini landfill sites.

2. Local village or settlement-based fee collection and/or payment system (around $0.80 per month per household would be accepted).

3. A reasonable distance (of 50–800 m) to install collection facilities.

4. Local village or settlement-based monitoring and enforcement of waste separation, recycling, disposa, and collection (which are mainly established depending on the local government and environmental education).

Solid waste management, which is a major responsibility of local governments, is a complex task that requires good infrastructure, adequate organizational capacity, and cooperation between numerous stakeholders in the public and private sectors and appropriate technical solutions (Dijkema et al., 2000). However, in the RATP, there are no municipalities, and most villages are not able to provide domestic waste services. Moreover, 17.65% of interviewees were not willing to pay anything. Thus, for such a rural waste management system to run effectively, villages and settlements should collectively negotiate a regular arrangement for waste management, and each village needs to define a central location to keep waste bins, as well as a regular local collection arrangement. Conversely, a demonstration or a mandatory village/settlement-based waste collection and disposal system should be developed.

Fortunately, 88.24% of interviewees were willing to participate in waste management, and their payment for such participation was relatively low. More than half of interviewees were willing to participate when their income reached $130.30–195.50 per month. Therefore, operationally, domestic waste management will be relatively easy in the RATP. In this region, the local village committee can be used to establish and operate the waste collection system and recycling activities. To promote recycling activities, it is suggested that the following factors be considered:

1. A waste management system should be planned and established, and infrastructure including collection, transportation, treatment, and disposal of waste should be enhanced and improved.

2. The public and communities should practice recycling activities.

3. Subsidies or tax privileges should be provided to recyclers or recycling companies.

4. Environmental education should be enhanced so members of the public learn how and why to separate waste.

Conclusion

The RATP is experiencing waste management problems such as shortages in waste disposal and treatment facilities, inadequate management capacity, increasing amounts of recyclables, and increasing per capita waste generation (Dan and Han, 2012). These issues have resulted in a large portion of domestic waste being burned, buried, or dumped freely. Although the environment has not been seriously polluted to date, water pollution and solid waste pollution associated with domestic waste are very common in the RATP.

Domestic waste in the RATP has unique features, including low generation rate, good compressibility and combustibility, a high portion of recyclable materials, low content of organic materials, low moisture content, and high ash content. These characteristics are influenced by the income sources and geographical positions of households to some extent.

Classified collection plays an important role in the management of domestic waste; therefore, it should be promoted widely on a household and village basis. The collection and transfer of recyclable matters are mainly dependent on recyclers or material recycling companies. Mixed domestic waste is suitable for treatment and disposal in relatively simplified landfills or existing landfills, while organic waste can be composted or fermented to produce energy and fertilizer and inert waste can be returned to farmland or landfilled. For villages and settlements close to urban areas, the most logical approach could be connection with existing waste removal and disposal systems operating in nearby urban areas. However, for remote rural areas, the disposal of domestic waste mainly depends on a localized mini landfill for a cluster of villages or settlements.

Moreover, educational level does not have a significant effect on knowledge of domestic waste and the income does not obviously affect willingness to pay. However, a variety of socioeconomic factors, including education and income, can still affect public attitude toward the management, treatment, and disposal of domestic waste. Thus, it is necessary to provide extensive environmental education in the RATP and it is very important to consider the economic elements of an effective domestic waste management program.

Acknowledgments

The authors thank Doctor He Mingxiong for his support during the course of the experiment and Zhao Ze for helping to edit the paper.

Funding

The authors acknowledge the Fundamental Research Funds for the Central Research Institutes of China (number 2012ZL004) and the Cultivating Program of Middle-Aged Key Teachers of Chengdu University of Technology (number KYGG201406) for providing financial support.

Additional information

Funding

The authors acknowledge the Fundamental Research Funds for the Central Research Institutes of China (number 2012ZL004) and the Cultivating Program of Middle-Aged Key Teachers of Chengdu University of Technology (number KYGG201406) for providing financial support.

Notes on contributors

Zhiyong Han

Zhiyong Han, Wenlai Xu, and Yanhua Xie are research associate professors at the College of Environment and Civil Engineering, Chengdu University of Technology, in Chengdu, China.

Zeng Dan

Zeng Dan is research associate professor at the Faculty of Natural Science, Tibet University, in Lhasa, China.

Guozhong Shi

Guozhong Shi is a research professor at the Biogas Institute of the Ministry of Agriculture, in Chengdu, China.

Lukun Shen

Lukun Shen is a researcher at the Biogas Institute of the Ministry of Agriculture, in Chengdu, China.

Wenlai Xu

Zhiyong Han, Wenlai Xu, and Yanhua Xie are research associate professors at the College of Environment and Civil Engineering, Chengdu University of Technology, in Chengdu, China.

Yanhua Xie

Zhiyong Han, Wenlai Xu, and Yanhua Xie are research associate professors at the College of Environment and Civil Engineering, Chengdu University of Technology, in Chengdu, China.