Pneumatic underground
waste collection.
Sahana Iva Raghavan (siraghavan.2013@business.smu.edu.sg),
Bachelor Of Business Management, Singapore Management University.
Executive Summary
Waste has had an increasing effect on mankind over
centuries. Right from contaminating our resources, to breeding diseases to
destroying our environment, it has done no good. Now with the rising
population, the total amount of waste produced is increasing at an exponential
rate.
This report considers the application of an
effective and sustainable alternative. Pneumatic waste systems are a developing
technology that can be used for efficient and clean waste management. Given
below are a detailed history of waste collection systems and the origin and
revolution of underground systems. This is then followed by the current
position of waste collection systems and whether there is scope for this system
in the future. This report is concluded by an evaluation of the system and its
applications.
Introduction
Last year alone, i.e. as of 2012, the total waste collected
was 7.27-million tonnes/ year. Every year we accumulate on all types of waste-
domestic and industrial, solid and non-solid, hazardous and non-hazardous, etc.
The largest form of waste however definitely comes from domestic waste systems
such as households, offices and restaurants. Domestic waste is the single
largest cause for a variety of problems ranging from lack of disposable area to
generation of harmful diseases.
Waste has many threats to pose. Waste may include any type
of garbage or rubbish, which may be from leftover food, to scrap paper to old
items, etc. However, what we humans fail to understand is that there is a
direct relationship between increasing quantity of waste and increase in
diseases and environmental damage. Waste produced, accumulates a lot of space.
In order to dispose the waste in any method possible, large areas are going to
be needed to store the waste until it can be disposed. Till an extent, waste
management techniques like landfill sites also take up large amount of a space.
With an ever-growing population, there already exists a critical pressure on
land resources. With increased amounts of garbage, there may not be place to
accommodate the expanding population.
Apart from that, waste collection and disposal includes a
lot of time and effort. Transportation of waste includes resources like money,
fuel and manpower. Also it must be noted that waste collection is a huge and tedious
process, starting from door- to- door collection, collecting from the public
places, segregating the waste and finally transporting it to the main sites
where it is to be disposed. In the process of collection, segregation and
disposal, it is very likely that a lot of waste will be “loosely” disposed,
meaning that lots of waste is left untouched and untreated. This is the most
dangerous consequence of waste, as these act as breeding grounds for diseases
such as dengue. Also waste, which is disposed into the water to flow down and
reach the landfill sites, is another major problem as it contaminates the
water. Contaminated water can cause serious health risks such as cholera and
spread of other infectious diseases. Solid domestic waste can become smelly and
then attract pests and rodents. Also there is the biggest threat, which is the
release of the greenhouse gas, methane. Methane captures heat 21 more times
than carbon dioxide, and hence poses a huge threat to increased global warming.
From the above discussion, we can conclude that garbage is
an increasing worry for people, and if not treated properly can cause
irreversible and serious damage to health, environment and resources. This
clearly implies that there is a need for a fast, effective and sustainable method
for dealing with waste collection and disposal. That’s where the pneumatic
waste collection system comes in.
Historical Perspectives
In order to fully understand the process of waste
management, it is important we consider its past implications and how it all
began. Right from 6500 BC, archaeological studies prove that Native Americans produced 5.3 pounds of
waste everyday. However around this period, man was known majorly to produce
biodegradable waste, which had close to a negligible impact on the environment.
It was known to be that the Mayans had “dumps”, which
occasionally exploded. This was the first ever known form of what we would come
to call “incineration”.
The first
ever known municipal dump in the Western world was found in Athens, Greece in 500 BC. Around the
late 14th century the English
Parliament banned waste disposal in waterways. This is known to be the first
step that was taken in a mass form of waste management, run by the government.
Yet, waste was still in control and posed no threat to humanity.
Around the 18th century,
however, events took a turn for the worst. With the advent of industrial
revolution, we saw the mass production of new materials such as “Steel. Copper,
Aluminum, etc. which began to be the largest composition of domestic waste at
the time. This new form of waste played a colossal impact on history. As these
wastes increased, it led to the spread of infectious diseases such as the
Bubonic Plague, cholera and typhoid fever, which altered the populations of
Europe.
Resulting
from this came the awareness among people about the danger of waste. In 1885,
the United States of America built
the first waste incinerator. In the late 19th century, recycling
plants were constructed as well. However, it wasn’t until the late 90’s that
different countries implemented laws about waste management.
As far as underground waste management
goes, the earliest form of this system was found in ancient Rome between 800 and 735 BC in the form
of sewers. It was a used to drain out the city’s dirt and regulate the water
supply. The Romans built a complex system, which included the water being drained
through central channels into
the main sewage and finally into the
rivers. This system is based on the same principals as our current pneumatic
waste collection systems. The Roman sanitation was considered the best-known
artifacts for its innovation, complexity in design and effectiveness.
The first pneumatic waste collection system originated in Sweden, with the first installation in Sollefteå
Hospital in 1961. It was the first time that the vacuum system was used in
order to transport waste in the multi-story hospital. With the great success of
the system, a 1100-unit system was built for a multi-story housing complex in Sundbyberg (Stockholm, Sweden), which
was active by 1967.
Current Situation
Currently, there are numerous ways in which we chose to
dispose off our waste. Some of these systems, which have been around for
centuries now are beginning to fail as they pose an irreversible threat to our
environment. People are currently more aware about the ill effects of waste and
the need for a solid waste disposal system in all countries, as to ensure the
overall sanity and hygiene of the population. Some of the most common methods
of waste disposal include landfills, incinerators, composting and recycling.
Landfills: This system includes the waste being
transported to large open areas where it is then buried in landfill “sites”.
Typically, all forms of waste can be buried in these sites, which are then left
many layers underneath the surface of the ground. It is one of the oldest and
most commonly known methods implemented till date.
However, landfills pose many harmful effects on the
environment. The largest problem is that landfills occupy too much space. Also
they contaminate the groundwater and leave the land barren, henceforth making
in worthless to be re-used again.
Incinerators: As discussed earlier, the earliest
known form of incineration came from the Mayans. Waste is loaded into huge
containers, which burn at high temperatures. This clears the waste fast, but
adds to air pollution and also is dangerous to operate.
Composting: This includes re-using organic,
degradable waste to add nutrition to the soils and act as natural manure.
Though this method poses no environmental damage, its shortcoming is that it
can be used only for biodegradable waste and not anything else.
Recycling: This is the re-use of all the solid
non-biodegradable waste, which can be used to serve other purposes. Main waste
in this category includes paper, bottles, plastics, etc. However, recycling is
a relatively new process and requires some form of basic knowledge to
understand the difference in the waste, which makes it hard to implement in
rural areas.
All the above waste techniques seem to have some flaws in
them, causing our waste to become harmful and are not being disposed off
properly. Hence the pneumatic waste collection system should be considered.
What
is a pneumatic waste collection system?
The pneumatic waste collection system, also known as
Automated Vacuum Waste Collection (AVAC), is a high-speed, underground waste
transporting system.
This is a system based on a network of fixed collection
stations through indoor/ or outdoor collection points. With the help of
connected pipes, the waste deposited at the drop-offs can be transported to the
collection units. Exhausters create air pressure in the ducts, and hence the
air stream transports the waste through the main line to the collection center.
The above diagram is a simple diagram depicting how the
entire process works, starting from the collection to the disposal.
Drop off points
These are the substitutes to dustbins. They are the start
point to the AVAC, and are very vital, as it must be ensured that these drop
off points are of the right size and are well sealed to offer best efficiency
and no wastage. These drop off points cant be found inside or outside. They can
be separated based on the following grounds:
- Size
- Wet
and Dry
- Recyclable
and Non-Recyclable
It is important that these drop off points are sealed as to
ensure that the garbage is not smelly and hence ensures clean surroundings as
compared to the original style of collecting garbage (through dumpsters and
drainages)
Vacuum
Air ducts
These are the ducts that help in the
transportation of the waste from the garbage drop off points till the refuse
containers. Vacuum systems first originated in the United States to collect
hospital laundry during the 1950’s. They are made up of lateral and vertical
metal sheets chutes, where the air intake is at the top of these chutes. Since these are gravity-type chutes, as soon
as the waste is dropped in, it automatically falls down to the bottom of the
pit where a collection valve is open. This collection valve then Figure 3. Vacuum ducts in the pneumatic system
connects to the mainline where there is a high intensity airflow, which draws
the garbage through the main line. For the vacuum air ducts to be effective,
certain criteria must be fulfilled. For example, the number of ducts in a
system, the total capacity of waste the system can hold, the distance along
which the system is spread, etc.
Large Refuse Containers and Final Transportation
The large refuse containers can be found at the end point of
all pneumatic systems. It is the collection point of all the refuse. Usually
large in size and kept in locations where they can be loaded and unloaded
easily, and large space for them to be stored. The cross section of these
refuse containers are square in shape to provide maximum surface area to store
the waste. The waste can then be transferred to the vehicles, through bypass
pipes, or the trucks can transport the entire container to
the final disposal site. In the case of
recyclable waste, these containers can be present at the sites where the waste
is recycled within the city. All the waste can be channeled to these locations.
However, when it comes to disposing other solid wastes, transportation of the
containers will be needed to the disposal sites, as they present outside the
cities in large open land areas. Figure 4.
Transporting trucks used
Currently, the pneumatic waste collection systems are being
implemented in over 30 countries, but only in urban areas and not on a large
scale.
Future considerations
There is an increasing awareness about the importance of
effective waste management, and hence many companies and countries are moving
towards implementing the pneumatic waste collection systems. As development
projects are rising in Europe and Asia, countries like Japan, Taiwan and Hong
Kong are leading the way for implementation. The city of Helsinki, Finland is planning to include this system in its latest
development project- the construction of Jätkäsaari residential area.
This system is not only being implemented in new upcoming
urban areas, but also in historical and cultural areas such as the famous city
of Leon, in Castilla y Leon (Spain).
Due to the solid waste being a huge problem, which is interfering with the
preservation of this historical site, the government of Spain is now looking to
install this system.
As far of the design of the system goes, the new Movac
system is said to contain two new compartments, third generation mobile vacuum vehicle, the
VL-5, and the patented screw tank concept. This allows the emptying time to be
cut in half and the collection capacity doubled. This increases the scope for
liquid and wet waste and well. With this type of system, we would be able to
segregate the liquid waste, only enlarging the horizon of this system. All
these innovations in the technology will definitely help the AVAC become more
sustainable, eco-friendly and not to forget, efficient.
The leading
companies that are into this technology are TransVac Solutions, USA (inventor
of the system), Envac, Sweden and Ecosir, Finland. Apart form these, there do
exist many more companies that are investing their time and money into research
and implementation of this technology.
Figure
5. The new Movac system
Conclusion
The pneumatic
waste collection system has a bright future laid out in front of it. This
entire paper has clearly outlined the scope this system has in bringing about a
revolutionary change in our waste management techniques. Some of the major
advantages of this system would be that we would be dealing with a fully
automated and mechanized system, including hardly any manpower in the entire
process. This increases the efficiency and ensures full-time functioning. The
limited manpower that would be necessary will be deployed only at a supervising
stage, and no less. This machine offers high safety standards and poses no
direct threat as an incinerator would. The complete sealing of the system
ensures no smell and ad odor to attract rats and other pests. Not only does
this improve the aesthetics of the our surrounding environment, it eradicates
all possible infectious diseases increasing the health standards and sanitation
among the population.
This system would wipe out the need
to throw solid or wet waste into water bodies, thereby improving water quality
and ensuring safe drinking water for everyone. With everything being automated,
there would be no need for the daily garbage trucks, thereby reducing sound
pollution in the cities. This would overall ensure quiet, clean and hygienic
neighborhoods, with more free space to concentrate more on social and cultural
activities. The amount of land resources this system can help save is enormous.
The largest impacts however, will be the benefits this system has to offer to
our environment. Lesser noise pollution, contamination, air pollution and
destruction. Cleaner and healthier environments will promote social, cultural
and economic growth among countries.
However, every
coin has two faces. With the numerous benefits that this system does offer, we
must understand that there are certain drawbacks as well. For starters, it has
large start up costs, making it an expensive investments which most less
economically countries would not be looking to adopt. Also in countries, which
are densely populated like China and India, it will be extremely hard to
implement these underground systems, as it would include lots of construction,
effort, time and money.
Most
importantly, this system does require some amount of expertise and knowledge as
far as research goes. Many developing countries may not have access to these
types of resources in the immediate future.
However, this is
an investment has greater pros than cons. It is an investment to a brighter,
healthier environment. It is one step closer to saving our natural resources
and preserving our Earth.
In reference to
sustainability,
"We do
not inherit the Earth from our Ancestors, we borrow it from our Children"
-Ancient
Indian Proverb
The
AVAC system could be the possible solution to a large number of our problems.
Though it will require thorough research and heavy investments, it is best if
governments around the world begin to consider this method as being the best
technique in effective waste management.
References
