Abstract: Universities are important parts of society. For implementing a resource-conserving and environmental friendly campus of university, the basic important standards are classification and recycling of campus garbage. Beihang University is the first university cooperating with government to implement ecofriendly green campus, and the leading university for classification and processing of campus garbage in Beijing. This research was mainly focused on investigation of working situation of garbage classification and recycling station, analyzation of problems existing in garbage classification system of Beihang University and distribution of propagable experiences obtained from investigation and analysis of campus garbage disposal system. This study was done by examining in the following aspects; classification method of campus garbage, relevant policy, construction of infrastructure, processing technology and public awareness. The campus garbage treatment station had been upgraded twice, and utilization rate of campus garbage was greatly increased, 59% of the campus waste reached to resourceful treatment. 53% of the total garbage processing was perishable materials which were sent to regeneration center and converted into renewable resources, such as methane and biological organic fertilizer, while 6% recycled waste were sent to the garbage recycling market after processing. However, many problems were still existing in the new garbage classification processing system for implementing green campus of Beihang University, such as low accuracy rate of residential garbage classification of community, incomplete campus garbage sorting equipment, lack of poisonous and hazardous waste bin, and incomplete publicity and less education to guide the effective mechanism for campus garbage classification process. Therefore, the following countermeasures should be adopted in order to become a perfect garbage classification and processing system in Beihang University: scientific formulation of convenient garbage classification system for residents, configuration of reasonable garbage classification equipments, establishment of perfect garbage processing and recycling system, strengthening of publicity and education of garbage classification to improve awareness of residents in the campus, referencing foreign garbage classification and processing methods. Perfect Beihang green campus garbage classification and processing system and mode modified with countermeasures could be popularized and become applicable not only in Beijing but also around the country.
Keywords: The garbage of Beihang University campus, garbage classification system, garbage treatment
Introduction
The rapid development of urban economic construction and unceasing improvement of people`s living standards had been bringing a lot of garbage. And so, classification of garbage is necessary to protect living environment and ecological environment of urban areas. The 18th National Congress of Communist Party proposed "Promote the construction of ecological civilization vigorously". Along with the further development of economy in China, classification and processing of municipal and residential garbage, and making them as recyclable resources are important standards to achieve ecological civilization.
School is an important part of society. Campus garbage has been increasing along with the expansion of school size, increasing in number of students and the improvement in living standards of teachers and students. Recycling and processing of the campus garbage is an important initiatives to build a resource conserving and environmental friendly green campus. The campus garbage in China mainly includes household waste, garbage from student apartments, rubbish from teaching and office area and kitchen waste. It has distinct characteristics of complicated different sources, large production and high difficulty in processing, unlike with other waste processing of countries. Therefore, the government of Beijing city, Haidian District, and universities promoted classification and processing of garbage to accelerate the construction of a harmonious and livable environment. Many studies reported that about 40% to 50% amount of waste can be reduced by classification and recycling of garbage and thereby reducing resource extraction, production and processing, and energy, manpower, materials, and other resources consumption in final disposal of waste. In addition, most of the campus garbage in university can be recycled, and the recycled value is relatively high.
Beihang University is the first university that has cooperation with government to implement green campus, and has been taking the lead in the campus garbage classification and processing in Beijing. The aim for implementation of green campus is to achieve a beautiful ecological environment, resource conserving, recyclable and environmental-friendly campus. Beihang University, an area of 1,800 acres, is located in Zhongguancun High-tech Park in Beijing, and is contiguous to the National Olympic Sports Center. At present, the total population of resident in Beihang University is 36776, including 4115 staff, 27811 full-time students, and the rest are the faculty families. Besides, there are about 2,000 floating people, the population density per unit area is relatively large and the production of garbage is also high. There are several main campus zones including residential area, dormitory area, staff quarters, office area, teaching area and logistics service area.
In order to make better and closer use of the campus resources, a 4-hour laboratory course was designed on the resource treatment process of the Beihang waste resource treatment station. Through field sampling, monitoring and investigation of the work of the Beihang campus domestic waste separation and recycling pilot project, this lab class analyzed the process of domestic waste resource utilization on Beihang campus in terms of campus waste separation methods, removal and transportation methods, facility construction, treatment technology process, waste generation and waste treatment rate. The experiment enables students to further understand the content of classroom teaching and apply it to practice, and systematically master the general steps and process flow of waste resource treatment process. To analyze the problems of the campus waste separation system and to derive a replicable experience through the investigation and analysis of the campus waste treatment system.
1. Experiment content
1.1 Monitoring of domestic waste sorting and collection system on Beihang campus
Garbage classification
(1) Monitoring the type of garbage cans and the way of sorting. (2) Monitoring whether garbage separation is implemented at the source on the College Road campus. (3) Survey the distribution of garbage cans on the College Road campus; (required to conduct a region-wide survey, first download a map of College Road and divide the work among each person to survey different areas). (4) Sampling according to the simple random sampling method.
Garbage collection and transportation system monitoring: (1) Monitor whether garbage is transported separately. (2) Monitor the frequency of garbage removal. (3) Monitor whether the garbage is transported by towed container system or fixed container system.
1.2 Waste separation system for domestic waste on Beihang campus
Food waste treatment system: (1) Monitoring of food waste pre-treatment system. (2) Estimation of the treatment rate of the facility for food waste composting treatment. (3) Drawing of food waste treatment process flow chart.
Garden waste treatment system for plants and trees: (1) Monitoring of yard waste pre-treatment. (2) Estimation of the treatment rate of yard waste treatment facilities. (3) Drawing of yard waste treatment process flow diagram.
Recyclable waste treatment system: (1) Monitoring of recyclable waste pre-processing. (2) Estimation of the treatment capacity of recyclable waste compaction and packaging facilities.
Non-recyclable waste treatment system: (1) Monitoring of non-recyclable waste pre-processing. (2) Estimation of the amount of non-recyclable waste disposed in landfills.
2.3 Data processing
The current total population in the Xueyuan Road campus is 36,776 (not including the mobile population).
Table1 Waste production per capita of different area in campus
|
Category |
Number of people (person) |
|
On-campus students living in student housing |
10918 |
|
Students living in the Student Residence of the Universiade Village |
9679 |
|
On-campus living staff and faculty |
404 |
|
Off-campus resident staff and faculty |
3355 |
|
Community Residents |
12420 |
The garbage output of students living in student apartments on campus and students living in the student apartments in the University Village is calculated at 0.5kg/d per person, the garbage output of working staff and community residents living on campus is calculated at 0.8kg/d per person, and the garbage output of working staff living off campus is calculated at 0.25kg/d per person.
Based on the total daily production of waste per capita, the treatment rate is calculated from the daily treatment capacity of the four types of waste tested
2. Main experimental results
2.1 Campus garbage and its classification
2.1.1 Campus garbage
Campus garbage can be defined as solid waste that are produced by daily activities providing service for daily life of residences in campus, and also includes the solid waste regarded as residential garbage according to laws and administrative rules. Therefore, the residential garbage produced by daily life activities of individuals and all units of area in the campus as well as the garbage from goods and service of life, waste produced from cleaning of public places and campus, and all kinds of solid wastes belong to the scope of campus garbage[2].
2.1.2 Classification of campus garbage of Beihang University
Campus garbage of Beihang University can be categorized depending on different sources including garbage from teaching area and dormitory, waste from office and canteen, residential rubbish, and trash of campus roads and landscape areas.
The garbage of teaching area mainly includes recyclable paper, other recyclable packing and wrapping plastic or paper, and waste bags and package boxes for foods. The dormitory garbage has more different types and larger quantities, including recyclable waste paper, non-recyclable toilet paper, waste plastics, such as plastic bags, plastic bottles and disposable plastic tableware and so on. The waste form office area is less in amount than others, in which recyclable paper is the main waste, such as text paper, package paper and other paper products. Food scraps and discarded vegetables are the main components of canteen waste. Residential rubbish includes kitchen waste, toilet paper, waste plastic and fluorescent tubes. The trash of campus roads and landscape areas mainly includes leaves, broken branches and discarded garbage.
2.2. Working situation of garbage classification pilot in Beihang green campus
At present, collection, transportation, and treatment system for garbage adopted by most of campus, community in Beijing are still unreasonable, and they have been using traditional mode "mixed collection - centralized transport – centralized processing" till now. To some extent of this, some recyclable, reusable components of household waste can become waste. On the other hand, this traditional mode will add some difficulties for dealing with garbage and achieving the expected treatment effect. In recent years, Beijing had improved its garbage disposal facilities with the development of city management level and many garbage pilots for classification, collection and transportation were set up. In 2013, Beihang University and its campus communities had become pilot for garbage collection and transportation. This pilot can achieve certain effect in various forms of publicity, guidance, and implementation in waste classification.
2.2.1 Policy and regulation for garbage classification
On May 1, 2020, the newly revised "Beijing Municipal Regulations on Domestic Waste Management" came into effect. Beihang University had been doing classification and recycling process for the campus garbage, and guided the classification work of campus garbage for whole university.
2.2.2 Garbage classification and processing mode in pilot
Depending on classification of different sources of garbage, campus garbage can be classified as the following four categories: kitchen waste, hazardous waste, recyclable waste, and non-recyclable waste. The kitchen waste includes the campus community garbage and canteen food waste, and the treatment process for that waste is composting and making organic fertilizer. Laboratory waste and hazardous waste should be separately collected, transported, and processed because chemicals and broken glassware are contained. Leaves and twigs and other plant garbage will be classified and processed separately, they can be used to make fuel rods by means of pyrolysis to provide energy and power for companies.
2.2.3 Activities for public awareness in garbage classification pilot
Haoye Property Management Company and logistic departments of Beihang University performed activities for public awareness to campus and community residents and students, and these activities included distribution of posters, advertisements, flyers, press reports etc. Haoye Property Management Company planned to launch “Barter - an equal exchange”: The Company will use organic fertilizer, made by composting kitchen wastes, to plant vegetables and will allow the residents to get these vegetables for their own needs by exchanging with recyclable waste collected by themselves from their residence. The logistic departments of Beihang University published some garbage classification pamphlets to help residents for classification of residential garbage. At the same time, garbage classification and recycling methods and their benefits were also publicized at Beihang High School and Elementary School, and thus students can get knowledge and become vanguard of garbage classification and recycling by sharing this knowledge to their parents. The school may initiate “the microcheiria to pull the dexterity”: leads the guardian through the student, and by using this model, the awareness and knowledge for garbage classification and recycling can radiate the entire society.
2.2.4 Introduction of garbage classification and processing system of pilot
The schematic diagram for garbage classification and processing system of pilot in Beihang University was shown in Figure 2.
2.2.4.1 Garbage classification at source
2.2.4.2 Garbage transportation
Two types of transit vehicles, one is electric vehicle with four garbage bins (Fig.6) and one with trash can with special number (Fig.7), were used for transportation of campus garbage. The vehicle with four bins is mainly responsible for transportation of residential garbage and these four bins will be filled with kitchen waste, recyclable waste, and other garbage respectively. Staff will do a simple classification to correct the wrong classification from each garbage bin printed with a mark named by logistic departments of Beihang. The other one is mainly responsible for the wastes from office area, teaching area and campus roads and landscape area, and cafeteria and laboratory waste will be transported separately by the vehicles with special numbers printed on it.
2.2.4.3 Processing of garbage recycling station in green campus of Beihang University
In order to implement green campus in Beihang University, garbage recycling station must have the following features: less occupied area, fully enclosed, no undesirable odor, and little impact on the surrounding environment, advanced waste classification and processing facilities.
As shown in Figure 2, garbage is transported to Beihang garbage recycling station where the first step is to weigh garbage and then the transported garbage are mixed to do first manual screening for selection of recyclable waste, such as plastic bottles, paper and white plastic bags. After the first screening, the garbage will be screened again by wind machine. The rest garbage can be categorized mainly into the followings: light weighed rubbish, compostable waste and garbage required to undergo secondary screening. Light weighed rubbish is screened in the conveyor by blowing with wind from above to continue the secondary manual selection, compostable garbage will be processed in pulverizer to become compostable material, while the rest garbage will be continued for secondary screening along the original conveyor, and finally, garbage will be compressed and packaged to finish completely the secondary screening.
Leachate generated during waste processing will be transferred to the sewer treatment through plash pumps of garbage recycling and processing station, and then it will be treated along with the sewage.
Garbage recycling and processing station also has a suction outlet that relates to biological deodorization reactor by piping. While the processing of garbage is running, workshop and all internal devices are all in the vacuum state to ensure that the undesirable odor cannot leak. The undesirable odor is collected to be deodorized by biological deodorization reactor. For deodorization process of undesirable odor of garbage, the smell generated in vacuum state will be inhaled by suction outlet to transport to biological deodorization reactor, and then deodorizing filter layer will "capture" and "fixed" the undesirable odor. Microbes in the filter will decompose and synthesize these undesirable odors to become carbon dioxide, water, and a trace amount smell. Finally, the odor will be discharged from air-vent after passing through gas processing in biological deodorization reactor.
In the garbage recycling and processing station, kitchen waste is not allowed to be mixed with other garbage; the kitchen waste from canteen will go directly into hogwash machine for being composted in order to make organic fertilizer. For this treatment process of kitchen waste, degreasing step must be done to remove the oil from food waste and this removed oil are not suitable as edible for no longer and so these oils will be transported to factory for making biodiesel fuel in order to provide energy.
According to statistics Table 1 The total daily waste production from per capita waste production is 21.4 tons. By monitoring result the daily disposal rate of the four types of waste as shown in Figure 2. The perishable amount reached to 53% of total amount of garbage processing can be accounted as the largest. All types of waste proportion for the total amount of garbage processing were shown in Table 2.
Table.2 Proportions of various waste from garbage processing
|
Various waste |
Perishables |
Recyclable waste |
Combustible material |
Other waste |
|
Proportion of total garbage processing |
53% |
6% |
21.5% |
19.5% |
Currently, the perishables are transported to recycling center for organic resources in Sijiqing where these wastes collectively with feces and landfill leachate, will be transformed into biogas, bio-organic fertilizer, and other renewable resources. The recyclable materials will be transported to the recycling market. And thus, two parts of garbage material can be eventually converted into renewable resources. It has proved that 59 percent of campus living garbage achieved resourceful treatment in Beihang green campus processing station. The utilization of campus garbage as "resources" can be greatly improved by doing this practice.
3. According to the experimental results, the students summed up the problems needed to counteract for improvement of garbage classification system
3.1 Less knowledge and accuracy rate of garbage classification
Residents are lack of professional knowledge in garbage classification. The residential garbage has many categories and their components are complex. Only few categories of garbage can be roughly classified. As an example, some residents do not know that battery, thermometer etc. are toxic and harmful, and so they will discard these toxic and hazardous waste with recyclable waste together into the trash bin. Because of this, these hazardous wastes will contaminate the recyclable waste and thus the campus waste resource utilization ratio will decline significantly. Therefore, it’s important to define various types of garbage. To define these wastes, the first thing to consider is the cost of garbage follow-up process [3], and the second thing is the value of recovered recyclable waste. For example, a clean newspaper and a clean plastic bag can be classified as recyclable garbage, but oil-soaked newspapers and plastic bags full of food should be assumed as other waste to deal with. If the cost of recycling is more than its recovered value, waste classification would change with it.
3.2 Bad garbage classification
For residents in the campus, there are only two kinds of garbage classifications bins for kitchen waste and other garbage, and for campus area, garbage bins are only three categories including kitchen waste, recyclable waste, and other garbage. Hazardous waste classification is not included in these categories. If residents have hazardous waste, such as batteries, thermometers, and lamps, they will put these hazardous wastes to recyclable waste bins, and so, it can cause these recyclable wastes to be contaminated and can no longer to be recycled. This can cause not only a waste of resources but also a certain risk for people`s health and the surrounding environment.
3.3 Incomplete facilities for garbage classification
3.3.1 Indoor garbage bins did not match with outdoor garbage bins
According to garbage bins shown in Fig 3 and Fig 4, for residents, the garbage bins inside buildings did not match with the garbage bins outside buildings; there are three trash classification bins outside the buildings compared to trash bins inside lack of trash bin for "recyclable waste". Because of this, it is easy to become residents confused about classification of residential garbage and so, they cannot make accurately classification of garbage. On the other side, the recyclable garbage from indoor garbage bins of household cannot be recycled very well resulting in a waste of resources.
3.3.2 Lack of necessary facilities conducing garbage classification
Inside the dormitory of Beihang University, there is no garbage classification bins and so students put the mixed garbage into a trash can. Then, this mixed garbage will be classified by the staff. This can cause not only greatly increase in workload for garbage classification but also reduce the resources for utilization of recyclable waste.
3.4 Imperfection of garbage collection, transportation, and processing systems
After treating the campus garbage in garbage treatment station of Beihang green campus, the treated garbage has only two possible ways, landfilling and composting, in the end of the process. There is no garbage that can be sent to garbage incineration plant for incineration process. It has indicated that garbage is not classified very well, processing system is imperfect, and this will result in wasting of some recyclable garbage and imperfect recycling of garbage.
3.5 Lack of publicity and public awareness in garbage classification
Publicity for garbage classification pilot generally stays in traditional ways and simple forms of garbage processing. Before performing activities for public awareness of garbage classification, it is very important to consider the limited scope of residential areas. As an example, while giving trash bins and plastic bags to residents, simply explanations of how to classify garbage to residents cannot play the role of publicity for introduction of garbage classification. And if there is no publicity of garbage classification in dormitory and other places, it could fail to guide public to understand the meaning of garbage classification. If the time for activities of public awareness is short, this can result in less effectiveness on classification of campus garbage, and so a certain effect of publicity cannot be achieved.
4. According to the experimental results, the students summed up the countermeasures for garbage classification and processing system
4.1 Scientific formulation of garbage classification
Garbage classification method should have strong inclusiveness, easy defining characteristics and good adaptability, which should relate to regional and social conditions, treatment facilities, public awareness, waste composition and so on. According to the status of Beihang campus garbage classification pilot, the garbage should be divided into the following categories.
(1) Recyclable waste: it refers to the garbage that can be recycled, used again, and must have low cost for recycling. It usually refers to the goods that can be recycled as long-term renewable resource in recycling site. It includes: (1) non-severely tarnished paper, such as newspapers, magazines, packaging cartons, paper plates, etc., (2) non-severely tarnished plastic, such as various clean plastic bottles, plastic foam packaging, and rigid plastics and so on, (3) metal, such as cans, tin cans, etc. and (4) glass: such as bottles and so on.
(2) Kitchen waste: food residues, leaves, offal from meat, pericarp and kernel of foods, waste food, etc. which are mainly consisted in school canteen garbage. These kitchen wastes can be processed to make organic fertilizers by microbial fermentation.
(3) Toxic and hazardous waste: they are hazardous substances that can be harmful to human health and natural environment directly or potentially, including abandoned household electronic products, such as batteries, fluorescent tubes, mercury thermometers, and abandoned paint barrels and buckets, expired cosmetics, expired medicine and so on. The recycled batteries including button batteries and lead-acid batteries that are used in watches and hearing aids for elder people, the abandoned and usual lithium batteries are not dangerous and they don’t need to be recycled.
(4) Other garbage: this includes food bags, storage bags, waste paper towels, discarded bottles and other cans with sticky foods.
4.2 Rational allocation of garbage classification facilities
In Beihang campus, the garbage classification barrels should be configured in accordance with uniform standards and technical requirements. Firstly, the color of trash bin must be unified: the color of bins for kitchen waste or compostable trash should be green, the color of bins for recyclable trash should be blue, and the color of bins for other trash should be gray. Secondly, the trash bin for toxic and hazardous garbage must be improved and added, and its color should be red. The volume of hazardous garbage bins can be smaller than others, and the classification frequency may be reduced depending on the amount of waste. Configuring garbage collection bucket must also be reasonable layout in order to be convenient for residents and school staff to do refuse delivery.
Garbage bins should be placed also in dormitory. If the space for garbage bin is limited in dormitory corridor, it will not be easy to put larger volume of garbage pails and the volume of garbage pails should be reduced. However, dormitory cleaners would require increasing the frequency of garbage collection and classification because of small volume of garbage pails, thereby it can prevent from incursion of mosquitoes and pollutions for corridor environment resulting from overflow of excessive garbage.
4.3 Establishment of impeccable garbage transport and treatment system
(1) For residential garbage transport process, the color of garbage transport vehicle should be consistent with the color of corresponding bins, which can be convenient for staff to do the garbage classification and transportation.
(2) Campus garbage treatment stations and Beihang logistics department can generalize the model for booking to recycle or going to the residents’ house to recycle garbage. This will save time, improve work efficiency, and can greatly improve resource utilization and garbage recyclable effectiveness.
(3) Using information technology to build video monitoring platform and realize visual management. Establishing digital monitoring in the school area with larger flow of people and places with garbage bin distribution to monitor the surrounding environment, and promptly correct the wrong garbage classification behavior. At the same time, installing video monitoring to realize the garbage disposal terminal orientation supervision and improve garbage treatment rate.
4.4 Creation of good awareness for garbage classification in public
Implementation of garbage classification, transportation and processing requires participation of all crew in campus of Beihang University. In additions, the Haidian district government departments should play a leading role in the activities for society and public awareness by performing with various media forms, such as newspaper column, campus education, theme activities, special movie, welfare animation, and volunteer activities. Taking advantages of newspapers, television, mobile media and network, knowledge concerning with garbage classification, transportation and processing can publish broadly, deeply, and persistently by printing and distribution of the popular science books to become popularize garbage classification knowledge and create incentives for public participation, mobilize public participation enthusiasm.
Recruiting some volunteers of campus through the Communist Youth League, various ways of different publicity for garbage classification can be carried out occasionally, and garbage classification awareness of the residents, teachers and students can be improved continuously.
Beihang University and Haoye Property Management Company will response the status of campus garbage classification and processing back to the campus community residents and students at regular intervals. Through the feedback of information, residents, teachers, and students will know the importance of classifying and recycling garbage for protection of campus environment and this will enhance the awareness of residents and teachers to protect campus environment [4].
In Western countries, environmental education started from the garbage at first. Garbage is the object that is closely related to our life. Accordingly, Beihang green campus waste recycling stations may become environmental education base for Beihang Elementary School, High School and College.
5. Conclusion
Garbage recycling and disposal is a major trend to help China become a "Beautiful China". In addition, it is also an important manifestation of green campus culture. The green campus waste treatment station established by Beihang University is used as the experimental base for solid waste treatment and disposal engineering course, which greatly improves students` ability to further understand the content of classroom teaching and apply it to practice. The experiment was designed to systematically grasp the general steps and process flow of waste resource treatment process and analyze the problems of campus waste classification system. Although there are still some problems in the campus waste separation, transportation and treatment system of Beihang University, these problems can be recognized and can be solved by proposing countermeasures. The relevant countermeasures derived from the results of this experiment can solve the problems in the waste disposal system, make up for its shortcomings, and maintain the eco-friendliness of the green campus. The further improved waste separation and disposal model of Beihang campus will be promoted and applied in Beijing and even in the campus of whole country.
References
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