Resources, Conservation and Recycling 39 (2003) 223 /237
www.elsevier.com/locate/resconrec
The environmental impact of municipal waste
management: the case of Guadalajara metro area
Gerardo Bernache
Centro de Investigaciones y Estudios Superiores de Antropologı́a Social (Anthropology Research Center),
Guadalajara, Mexico
Received 1 June 2002; accepted 1 September 2002
Abstract
This paper discusses municipal waste generation and the municipal management system in a
Mexican city and identifies the main pollution vectors. There is a scarcity of relevant
information on waste generation at the municipal level, as well as the types and characteristics
of the waste generators. Only recently has the management of municipal waste, in Mexico,
improved via better data collection and the introduction of new teams of professionals in
charge of sanitation departments. However, the growth of waste arisings in Mexican urban
settings during the past decade has overwhelmed the staff in charge of municipal waste
management in large cities (i.e. those urban areas with more than 500 000 people). Part of the
growth in waste generation corresponds to the population growth within the city partly via
rural to urban migration. Increased consumption as well as the presence of more packaging
material in processed goods has also been a contributing factor. Waste collection has tried to
keep pace with the growth of municipal waste generation but has rarely succeeded. The most
problematic issue of all in waste management in large cities, like the metro area of
Guadalajara, is the disposal of the wastes. This paper reviews the scale of the waste problem,
the corresponding municipal collection and transport as well as the final disposal of wastes in
local ‘dumps’ and the resulting environmental pollution vectors that pose a number of risks to
local populations.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Municipal waste; Waste management; Waste data; Environmental impact
E-mail address: [email protected] (G. Bernache).
0921-3449/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0921-3449(03)00029-6
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G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
1. Introduction
With a population of 3.4 million people, the metropolitan area of Guadalajara
ranks as the second largest city in Mexico (INEGI, 1984, 1996, 2001). The city is
composed of four municipalities, while another three are already in the process of
being incorporated into the metropolitan area. Table 1 shows the distribution of
population among the four main municipalities within Guadalajara.
Guadalajara is the central municipality and the one with the largest part of the
metro population, most of its territory is already occupied by residential tracts,
commerce and industrial sectors, it is the center of state government with several
public and private universities.
Zapopan is the largest area and offers opportunities for land development. In the
past, this municipality had the largest corn production in Mexico. Now, Zapopan
provides the better residential developments in the metro area.
Tlaquepaque and Tonala are old Mexican towns that were engulfed by urban
growth. The two municipalities are mostly residential, with some craft and local
artisan production, as well as commercial and tourist-related activities. In terms of
residential dwelling, most of it is middle and low income groups. Some of the poorest
neighborhoods in the metropolitan area are located in Tlaquepaque and Tonala.
2. The solid waste problem
The research method used in this Guadalajara study follows the research strategy
proposed by Rathje (1984), Hughes (1984) and Restrepo and Phillips (1985). The
focus is on household production of solid waste, given the assumption that in
Mexican urban settings the main component of municipal solid wastes is residential
wastes (Castillo, 1990; Phillips et al., 1984; Rathje et al., 1985; Restrepo et al., 1991;
Ramı́rez and Chávez, 1998; Arias et al., 2001; Buenrostro, 2001).
The primary aim of the research was to assess the daily household production of
waste. In addition, it was planned to estimate the total amount of residential waste in
the four municipalities through analysis of the daily records of all municipal waste
entering the local dumps and landfills.
Table 1
Population in the four main municipalities studied
Municipality
Population
Percent
Guadalajara
Zapopan
Tlaquepaque
Tonala
Metro area
1 612 697
1 009 817
491 061
311 309
3 424 883
47
30
14
9
100
G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
225
First, a sample group of 300 households were selected from the metropolitan area
(using Census data). Second, the families were contacted by the research team and
agreement for their participation in the study was obtained. Third, all their
production of solid waste during a 7-day period was collected during three pickup visits. Fourth, a brief questionnaire was administered in order to obtain basic
information on the household composition, income and other factors. Fifth, all the
household waste obtained was sorted by material composition categories, weighed
and recorded.
The total waste generation in the metro area was obtained from our field work,
where the research team recorded all municipal waste entering the three sites located
in Tonala and Zapopan for a 12-week period.
A number of interviews were also conducted with the public officials responsible
for municipal waste management. This was the basis for planning further studies,
which reviewed records to get information on waste collection in the four
municipalities.
For waste disposal and recycling, the research team made direct observations at
the relevant sites, and took records of weight and types of sorted materials that were
destined for recycling.
Finally, five case studies of large municipal dumps were produced to illustrate
some of the problems that exist for waste management in urban Mexico.
3. Waste generation: residential and municipal solid wastes
3.1. Characterization of household solid waste
The average generation of household waste per person amounts to 0.509 kg/day, a
typical family of five members would produce over 2.5 kg of waste. Most of it comes
from the kitchen in the form of peelings, bones, seeds and other by-products of food
preparation processes starting from fresh produces and raw ingredients (Bernache et
al., 2001). About 41.6% of the waste coming out of households is kitchen organic
wastes, another 12.2% comes from garden and plants maintenance (grass clippings,
small branches, dry leaves, and the like). In terms of the contribution of other
categories to the profile of household waste, paper and cardboard was 10.6%,
plastics 9.6%, glass 4% and metals 1.5%.
A more detailed breakdown of contribution by material categories is presented in
Table 2.
Table 2 shows that the five most important categories are kitchen refuse, garden
clippings, paper, ‘other miscellaneous items’ and disposable diapers. Four other
categories are also important, although they contribute less than 5% each: rigid
plastic containers, plastic film and bags, transparent glass, and cardboard.
An alternative way to classify residential waste is to divide it into three general
categories: kitchen and garden organic, packaging, and other items. Details on
packaging content is shown in Table 3.
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Table 2
Profile of household waste
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
Material categories
Grams person per day
Percent
Cotton
Cardboard
Leather
Fine residue
Waxed cardboard packaging
Vegetal fibers
Synthetic fibers
Bones
Rubber
Tin
Ceramic and china
Wood
Demolition debris
Ferrous metal
Non-ferrous metal
Paper
Disposable diapers
Plastic film and bags
Rigid plastic
Polyurethane
Expanded polystyrene
Garden and plants
Kitchen organic
Textile
Color glass
Transparent glass
Other miscellaneous items
Total
0.10
12.59
2.25
5.90
2.15
2.19
1.43
4.03
1.85
2.74
2.84
3.29
5.92
4.10
0.71
39.12
32.29
21.33
22.56
0.19
1.38
62.02
211.69
8.63
3.13
17.20
37.22
508.85
0.02
2.47
0.44
1.16
0.42
0.43
0.28
0.79
0.36
0.54
0.56
0.65
1.16
0.81
0.14
7.69
6.35
4.19
4.43
0.04
0.27
12.19
41.60
1.70
0.61
3.38
7.31
100.00
Table 3
Packaging content of residential wastes
Residential waste categories
Percent contribution (of total weight)
Organic (kitchen and garden)
Packaging
Other wastes
53.8
17.5
28.6
Source: Bernache et al. (2001).
In Table 3, organic is composed of kitchen and garden residues, while packaging is
composed of all kinds of wrappings, boxes, bottles, containers, tetrapaks, egg
cartons etc. Packaging come in a variety of materials, mainly: plastic, paper and
cardboard, glass and metals (tin and aluminum). In this case, the ‘other wastes’
G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
227
category includes a variety of materials like discarded textiles and shoes, disposable
diapers, broken ceramic, sanitary wastes, wood and ceramics.
A study of the role of packaging in Mexico City conducted by Rathje et al. (1985)
reported that packaging was 20% of the total household wastes, compared with 40%
in US households. The authors concluded that ‘almost half of the sample refuse from
Mexico City was food debris; in USA household refuse, food debris was only 20% of
weight’ (Rathje et al., 1985; Phillips et al., 1984; Restrepo and Phillips, 1985;
Castillo, 1990; Restrepo et al., 1991). If we set other differences aside, packaging has
varied little as a percentage of household waste in Mexican urban settings.
3.2. Municipal solid wastes
Household waste is an important part of the municipal solid waste stream
(Buenrostro et al., 2001; Bernache et al., 1998). Our results indicate that 56% of the
municipal waste comes from homes. The other 44% comes from a variety of sources:
public parks, markets and streets; governmental institutions, schools and universities; commercial centers etc. Industrial, non-hazardous wastes are only a minor
part of the total, since most are materials suitable for recycling (e.g. cardboard,
wood, and plastic), they are presently recovered and handled, mostly, by small
recycling firms. Most industrial, non-hazardous wastes that enter the municipal
waste stream come mostly from dinning facilities, office activities and the like.
Although the research was mostly directed to household waste production,
additional time was given to monitoring all municipal disposal sites and recorded the
amount of waste deposited each working day for 12 weeks. The four municipalities
of the metropolitan area produced a total of 3119 metric tonnes of solid waste per
day. The daily average per capita production of municipal solid wastes in the
metropolitan area is 0.911 kg. Table 4 presents the detailed figures for household
waste as a part of the total municipal.
Guadalajara and Zapopan are the two main municipalities in the metropolitan
area, therefore, they have a larger number of industries and business with more
commercial activity. The composition of the municipal waste, in terms of the
contribution of household, shows the differentiation of areas of the city by economic
activity.
Table 4
Residential component of total Municipal Solid Waste (1997)
Municipality
Residential wastes (tonnes)
Municipal solid waste (tonnes)
Percent
Guadalajara
Zapopan
Tlaquepaque
Tonala
Total
805
583
244
110
1743
1506
1093
367
153
3119
53.4
53.3
66.5
71.9
55.9
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The per capita generation of municipal wastes is 0.492 kg/day for Tonala and
0.748 for Tlaquepaque, while Guadalajara and Zapopan produce 0.934 and 1.082 kg
per capita, respectively. The differences are related to the types and scale of
economic activities in each area (Bernache et al., 1998, 2001).
4. Municipal waste management in Guadalajara metro area
4.1. Collection and transport
Collection practice varies greatly throughout the metropolitan area. The urban
areas of Zapopan and the municipality of Guadalajara have the best collection
system, with daily pick ups in most neighborhoods (90 /95%). However, as the
neighborhoods get further away from the central areas, they tend to receive a service,
which is less regular. Such is the case of marginal neighborhoods in Tlaquepaque and
Tonala. The marginal zones towards the outskirts of the urban center do not get a
regular public services; waste collection occurs once a week or even longer. Tonala
and Tlaquepaque provide regular collection for some 80% of the local residents.
The collection of municipal solid waste is the responsibility of the four
municipalities and the concessionaire CAABSA. Table 5 contains data on the total
number of units working on municipal solid waste collection.
Collection and transportation of municipal solid waste is not as efficient as it
could be. Some 77% of the collection trucks operating in the metropolitan area,
travel long distances to take their load directly to the municipal landfills, because
only two transfer stations are in actual operation. One serves the concessionaire
CAABSA, located to serve the trucks working on the south side of Guadalajara, and
the other is towards the northwest of the metropolitan area and serves the
municipality of Zapopan. Only two, out of the five service providers, have a transfer
station that allows them operational efficiency in collection and transport of
municipal wastes (Ramı́rez and Chávez, 1998; Bernache et al., 1998; Arias et al.,
2001).
Table 5
Collection equipment and personnel
Municipality
Collection trucks
Personnel
Guadalajara Sanitation Department
Guadalajara Concessionaire CAABSA
Zapopan Sanitation Department
Tlaquepaque Sanitation Department
Tonala Sanitation Department
Total
46
158
120
48
38
410
184
602
500
275
180
1691
Source: Arias et al. (2001).
G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
229
4.2. Separation and recycling
Studies indicate that only 2% of the total municipal solid waste is separated and
sold to commercial and industrial agents that recycle it. Separation of materials in
the municipal solid waste stream is performed mostly through unregulated means.
The most important agents are the scavengers working at the site of Coyula (600
registered, although not all of them work at the same time in a given week day), and
the sanitation workers assigned to collection trucks. On a lesser scale, there is also
the materials processed by a small group of scavengers (40 of them) working at the
Belenes Transfer Station in Zapopan, and in addition the occasional work of the
separation bands at the processing plant located at Los Laureles Landfill (Ramı́rez
and Chávez, 1998; Bernache et al., 1998; Long, 1999; Arias et al., 2001). The
amounts of materials separated and commercialized by scavengers and sanitation
workers is in the order of the 69.6 metric tonnes/day (2.2% of the municipal solid
waste of the metropolitan area).
The profile composition of the 69.6 daily tonnes of separated materials sold to
recyclers is the following: glass contributes 35%, plastics 30%, paper and cardboard
10% and metals 10% (Bernache et al., 2001). The profile changes according to
variations in market prices, seasonality and other factors.
In early 2002, the municipality of Guadalajara and the concessionaire CAABSA
launched a small-scale curb separation program. The program functions only in four
neighborhoods. Although, the results might be modest in terms of total tonnage
separated and recycled (less than 1% of the total municipal waste generated), the
program is the first serious project that has used environmental education for
residents and allied this to a new approach to curb-side separation and collection.
This program will expand to cover other areas of the city after a 6-month pilot.
4.3. Waste disposal
The strategy for waste management in the four municipalities of the metro area is
simply based upon burying 98% of the municipal waste. This is considered the
simplest and cheapest way to dispose municipal solid waste, especially if the
municipal sites are operating like dumps without the necessary pollution-control
infrastructure.
There are reasons for the lack of sustainable practice. These include:
. municipal authorities do not consider that economic investment in municipal
solid waste management has political value;
. environmental and sanitation department authorities have limited experience and
little specialized knowledge on environmental issues;
. workers with no motivation or incentive for change; and
. little knowledge of possible technological innovations.
The problem with burial of wastes is that most sites do not have the necessary
design and construction quality that are central for a sanitary landfill (Castillo, 1984;
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Bernache et al., 1997; INEGI, 1998; Israde et al., 1999; Ojeda et al., 2002). For
example, all sites in the metro area were so positioned because authorities found the
opportunity to buy or use a tract of available, cheap land close to the city.
Geological and hydrological considerations were not taken into account. Nowadays,
entrances to the sites, are controlled, but that was not always the case and illegal
loads were admitted onto the site after bribing the site manager. Moreover, the sites
do not have any pollution control structures built in (such as San Gaspar), or the
pollution control systems were added after years of site operation (such is the case of
Coyula, Los Laureles and El Taray) and often do not function to a high enough
standard. Gas venting tubes are often clogged and leachate capture systems often
overflow.
Open and controlled dumps (quasi landfills) generate a number of pollution
problems in, and around, these sites. San Gaspar was an open municipal dump with
no attempt whatsoever to reduce environmental impact or pollution control. Coyula
started as a sand extraction site, for construction, and was only later turned into a
dump. After 10 years of operation, the first pollution control devices were installed.
Both Los Laureles and El Taray were given authorization to operate as ‘Recycling
Plants’, here open space was needed to produce organic compost and to bury small
amounts of non-recyclable materials. After 1 year, both plants started to function
more like an open dump than a recycling plant. Nowadays, the plants are mostly
non-operational (except for one band at Los Laureles). Finally, Picachos is the first
sanitary landfill site in the metro area, it is located in Zapopan and receives mostly
solid waste from this municipality, even though there is an open option for the other
municipalities to use this landfill. However, even in this case the location of the site
was decided because the opportunity arose to purchase low cost land and not
because of geological and hydrological considerations.
The metro area of Guadalajara is now experiencing another problem related to old
landfills; since a growing population is settling and building their homes near to
closed-down dumps. Some nine closed sites in Guadalajara metro area have a
residential settlement next to their perimeter. This means a heightened risk for those
residents because of a number of public health issues.
5. Disposal sites
Guadalajara has depleted its areas of urban reserve and, therefore, has no
available land to locate a disposal site. The municipality now owns two land tracts
located in the territory of Tonala, where two large ‘controlled dumps’ operate.
However, Guadalajara does not run the collection and disposal; a private company
has the concession and operates the service. Tonala and Tlaquepaque have their own
departments for solid waste collection, but resort to the sites owned by Guadalajara
to dispose of their daily municipal waste. Both San Gaspar and Los Laureles have
been used by three municipalities (Guadalajara, Tonala and Tlaquepaque) on a
regular basis.
G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
231
5.1. San Gaspar
Guadalajara and Tonala have been involved in a kind of partnership since the mid
1980s, because Guadalajara lacked suitable tracts of land to locate and operate a
waste disposal site. Guadalajara began talks with a neighboring community of San
Gaspar by the year 1985. Even though this community is located within the territory
of Tonala, this municipality was not taken into account in this negotiation. This was
supposedly a contract between two private parties. By 1988, Guadalajara bought
another large tract of land in Coyula, and a few years later Los Laureles */also
located within the territory of Tonala.
During the first years of operation at San Gaspar, the municipality of Tonala was
not recognized as a legitimate authority to oversee the operations at the site.
Therefore, the site did not have the clearance to get a municipal license to operate.
Guadalajara paid the municipality of Tonala*/for their tacit acceptance of the
disposal sites */by providing them with an ‘exchange’; patrol cars, ambulances or by
paving so many kilometers of main avenues connecting the two central areas. This in
turn allowed Guadalajara to run the daily operations with little constraint.
From 1984 until 1988, communal areas of San Gaspar were used as dumps. By
1980 and 1981, the community leaders of San Gaspar had given right of sand
exploitation to several private parties. After they took all the available constructionsand, they left a number (13 different sites) of large excavated rectangular beds. Each
bed measured from 3 to 6 m deep; the surface area of some them were 100 m / 250
m. By 1984, Guadalajara had negotiated with local community leaders for use of the
site and paid them for the right to dispose of its municipal waste in these beds.
During those 4 years of operation, the municipality of Guadalajara took control
of the area and managed the disposal of municipal wastes at San Gaspar, at the same
time a large group of people from the local community started to work there as
scavengers.
By the mid 1990s, some 7 years after the site was closed down, a group of
authorities and community leaders started to sell parcels of land for residential
building construction. The prices of those lots were cheap, compared with other
locations nearby, therefore, all the available land was sold promptly to people that
were not familiar with the site history. Since the excavated beds were distributed
along a large tract of land, not all the terrain was landfilled. Many soon discovered
that the ‘trash fill’ would not support the brick structure of the new homes and they
had to abandon their plots. However, there are presently more than 100 homes on
this very polluted environment; the open spaces are used for grazing (cows and
goats), as well as for growing crops such as corn and other vegetables which are sold
locally.
The main problem here is the leachate that has polluted five drinking water wells
that can no longer be used. Leachate also migrates and pollutes the water in nearby
residential underground tanks.
The leachate has a high conductivity and a high presence of total coliforms
(160 000/100 ml). Although, toxic pollutants and heavy metals are present, their
range is within established limits (Bernache et al., 1997).
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5.2. Los Laureles
This site started as an open dump during the early 1990s. First, it was used by the
municipalities of Tonala and Guadalajara. Then, concessionaire CAABSA took over
in 1995 and built a waste separation facility to select and remove all recyclable
material out of the waste stream. According to the concession contract, the adjacent
land was to be used as an area for organic compost production and for the
disposition of ‘rejected’, non-recyclable materials. Nowadays, the separation plant
functions at minimum capacity and only a small amount of compost is produced.
Los Laureles operated as a municipal dump for 5 years, up to the year 2000.
During the years 2000 and 2001, most available land in this 90 acre site was
converted into a controlled dump and for the first time, adequate perimeter control
was established. Plastic membranes were fitted to prevent movement of leachate; two
large leachate collection pools were built and a long trench was dug around the
perimeter to collect leachate run off. Leachate collection and treatment is around
85% efficiency. The rest simply escapes from the site towards downhill slopes. This is
what CAABSA and environmental authorities call ‘a controlled dump’, a concept
that implies that the operation of the site almost complies with the standards set for a
modern sanitary landfill.
The location of Los Laureles is problematic because it is located upstream of two
small ravines situated on the perimeter. Leachate from the site runs down a hill and
crosses a small irrigation channel that serves many agricultural and urban users. A
kilometer ahead of the site is Tololotlán, the community that makes use of this water
before the stream meets the Santiago river.
Leachate samples indicated the presence of lead (20 mg/l, three times greater than
the established limit of 5.0 mg/l). Biological contamination is also high as shown by
the presence of total coliforms. There is a high conductivity (up to 40 000 mV/cm),
with appreciable amounts of oils and greases ((330 mg/l, way above the B/100 mg/l
upper limits set by local regulations). Hexavalent chromium has also detected, with
an upper range of 40.41 mg/l, way above the B/1 mg/l limit (Bernache et al., 1997).
5.3. El Taray
Zapopan is the only municipality that has complete independence or autonomy in
the process of waste management. By mid 1995, the municipality of Zapopan gave
the concession of final disposition and treatment of all municipal solid waste to the
concessionaire ARROW. A 40 acre site (El Taray), owned by Zapopan, was lent to
the company to build a separation plant and all their facilities needed for full
operation.
ARROW, the concessionaire, operated the site for 1 year and then their contract
was cancelled by the municipal authorities and the Sanitation Department took over
the operation of the site. The municipality claimed that the concessionaire ARROW
had committed fraud and did not comply with the conditions established in the
contract.
G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
233
El Taray was originally planned to locate a couple of large separation plants that
would generate more than 200 daily tonnes of separated materials ready for
recycling. The task indeed proved to be too difficult for the company managers; they
had no previous experience in operating a separation plant. Many other problems
developed during the first year of operation. At the end of the year the site managers
were burying most of the 1000 tonnes of waste that they received per day.
As soon as Zapopan Sanitation Department took over the site in 1996, the only
strategy for waste management was burial. The plant was set aside and the terrain
was prepared to receive the daily tonnage produced in Zapopan. By 1997, the
municipality produced an average of 1097 tonnes/day. A more recent study indicates
that an average of 1300 tonnes of waste were buried at El Taray during 2001 (Arias
et al., 2001). This was the last year of operation; by the fall of 2001 the operation was
moved to a new site some 4 km to the west-Picachos landfill.
Environmental concerns at El Taray are the leachate run off that is collected in
two large pools at the base of the two main pyramidal landfill. Recirculation is
practiced, but not on a daily basis, maybe twice a week.
El Taray is far from the city limits, 15 km away from the outskirts of Zapopan,
therefore, there is no a problem of urban encroachment onto the site. The main
commercial activity in the locality is agricultural plus a growing number of weekend
homes for families living in the city. However, El Taray is located in a terrain of hills
and rocky elevations, a concern leachate which may, during the monsoon season,
reach streams and underground water.
Leachate analysis suggests: hexavalent chromium at 13.72 mg/l, lead at 2 mg/l
(also a red flag, although is within the 5 mg/l acceptable limit), and biological
problems with the presence of certain micro-organisms (Bernache et al., 1997).
5.4. Picachos
Picachos began to operate in 2001, this site complies with the requirements of a
sanitary landfill and will have an operating life of some 20 years. The site was built
under a metropolitan agreement and other municipalities also contributed financially for the construction of the landfill. Picachos has the best facilities in the
metropolitan area. However, the fact that it is located some 17.5 km outside the city
makes the transportation expensive, compared with the other two sites. Nowadays, it
receives over 1300 metric tonnes of municipal solid waste per day.
Zapopan uses the Picachos landfill to dispose off its solid waste, the site was built
with great effort and care to comply with environmental regulations. However, two
problems are still evident with this site. The first is that the location was not defined
in terms of the topography and hydrological characteristics of the land, rather
because it was an available parcel of land, large enough and at a low price. It is
located on the top of a hill, mostly surrounded with steep terrain, some garbage
trucks have difficulty in climbing the access road. The second problem is that
Picachos uses the recirculation method for leachate treatment. Runoff is directed
toward a huge concrete pool, which evaporates some of the water, and receive some
kind of low-grade chemical treatment. The leachate is then pumped back to the top
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G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
of the landfill to irrigate the top layer. There has been no laboratory testing of
leachate from this site and it is yet to be confirmed that the site infrastructure is able
to contain all leachate runoff during the rainy season.
5.5. Coyula
Coyula is a 14-year-old municipal dump and is the second of the three sites, which
have been operated by Guadalajara. This is a large site with a history that reflects
most of the common problems that faces waste management at municipal level in
Mexico. According to previous management plans, this site was going to be closed
during the late 1990s. But the concessionaire CAABSA has extended the operating
life of this by landraising the overall structure. The urban location of this site is the
best in terms of transportation cost, since it is located within the metro area, close to
the central area of Tonalá and with easy access from Guadalajara and Tlaquepaque.
Archaeologists have provided accounts of the destruction of pre-Hispanic remains
at the site (Weigand, 1996; López, 1998). The destruction of the ruins began with the
excavation to obtain sand for the construction industry. The second part began with
the massive burial of municipal waste at the site. Eventually, a small fence was built
around the main pyramid to try to protect it, but it was too little too late. Decision
makers should have ensured the protection of the archaeological remains at Coyula.
The site nowadays extends over 100 acres, it reaches a height of 25 /30 m. The site
was receiving about 37% of all municipal solid waste produced in the metro area of
Guadalajara, a total of 1142 tonnes/day. The production of leachate at Coyula is at a
minimum of 50 000 l/day of runoff.
Studies on leachate from this site have found high conductivity, high oils and
grease and a significant amount of cyanide (Bernache et al., 1997).
5.5.1. Scavengers
Scavengers have been an integral part of the traditional Mexican approach to
waste management. Héctor Castillo has given us an ample review of the work of
pepenadores, their organization, and their kinship networks that spread beyond the
dumps into the formal organization of the Sanitation Departments in Mexico City
(Castillo, 1984, 1990). By the mid 1980s, Camarena had commented on the situation
of the cooperative society of scavengers in the border town of Ciudad Juárez, in
northern Mexico (Camarena et al., 1986).
The largest group of pepenadores in the metro area of Guadalajara work at the
site of Coyula, where some 600 of them are registered to work. On any given day,
only 150 pepenadores would be actually working on the solid waste just deposited by
sanitation trucks. Scavenging is a family business, therefore, the father and oldest
children would be at the ‘field’ searching for materials and placing them in a large
sack. Once the sack is full, they will go to a temporary ‘camp’ where the wife would
receive the load. She will proceed to classify residues by material composition and
make final separations placing materials in piles or medium-sized containers. Often,
a buyer will come with a truck and buy the materials on the spot. The scavengers
G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
235
have the option of selling their products outside to get better prices for the materials,
but only if they can manage to get transportation for their load.
By any standards, quality of life for those families of pepenadores is in the low.
Often, small children, infants and toddlers are playing around the ‘camp’ at the top
of the dump. Health issues are the central concerns here, not many of the authorities
seems to be aware of this.
6. Conclusions
This paper deals with the generation of solid waste and the problems associated
with waste management (collection, transport and disposal) in a Mexican city.
Citizens produce an average of 0.509 kg of residues in their homes, and an average
per capita production of municipal solid waste of 0.911 kg/day.
The total production of solid waste in the metro area of Guadalajara is around
3119 metric tonnes/day. A recent study made by Arias et al. (2001) suggests some
4106 tonnes/day. Given the difficulty in obtaining precise data it is not possible to
arrive to an exact figure. The figures reported by Arias et al. (2001) may suffer from
some distortion due to verbal reports (interviews) with municipal authorities. It is
considered that by 2002, the daily production of solid waste could well be within a
range of 3500 daily tonnes.
Collection of solid waste, residential and other sources, has been improving during
the past decade, but still there is work to be done, especially in poor neighborhoods.
The traditional system of collection still permeates the operation of the sanitation
departments in the metro area, where the best service, with daily curbside pickup, is
provided to central areas, business and the better residential areas. Poor neighborhoods, slums and marginal areas have collection service perhaps once a week, mostly
every 2 weeks or may be receive no collection service at all.
The city’s image also suffers from the lack of any pro-environment behavior by
citizens; litter in the main streets and avenues is very common. It seems that the ideal
for many citizens living in Guadalajara is to have an army of municipal workers
sweeping the streets, since most local residents do not seem able to restrain from
discarding every conceivable item right on the public areas and streets.
However, the main problem in Mexican cities is the lack of a real waste
management plan (Bernache et al., 1998; Ojeda et al., 2002). Public authorities in
charge of waste management have reduced the idea of management to the collecting
of residential and business/commercial residues, and burying all municipal wastes in
local so-called ‘controlled’ dumps. So far, environmental education has not played a
role in promoting awareness of this problem, nor in motivating local residents to
reduce waste and participate in residential waste separation programs. This is a
consequence of having municipal authorities with little interest in providing
appropriate human and economic resources to develop a sustainable strategy for
waste management; there is no unified strategy for the metropolitan waste problem.
A pressing concern is the environmental degradation that results from the poor
practices of final disposition of solid waste. Leachate loaded with pollutants either
236
G. Bernache / Resources, Conservation and Recycling 39 (2003) 223 /237
escapes from the perimeter of a site or is collected in large pools in order to pump it
back to the top of the dump; adhering to a recirculation model of leachate
‘treatment’.
The lack of a sound professional knowledge base as well as the absence of
environmental supervision of the activities of the municipalities and the concessionaire, results in a waste management strategy that generates a number of new and
complex problems. The metro area of Guadalajara, still has a long way to go to
develop a comprehensive, efficient and environmentally-sound strategy for sustainable municipal waste management.
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