Philippine Journal of Science
150 (4): 611-623, August 2021
ISSN 0031 - 7683
Date Received: 18 Jan 2021
Waste Profile and Waste-to-Energy Conversion
Potential of Medical, Hazardous Industrial,
and Electronic Residual Wastes
in Metro Manila, Philippines
Ferdinand Manegdeg1,4,5, Analiza Rollon2,4,5, Eduardo Magdaluyo Jr.3,
Florencio Ballesteros Jr.2,5, Louernie de Sales-Papa5, Eligia Clemente3,5,
Emma Macapinlac2, Roderaid Ibanez1, and Rinlee Butch Cervera3,4,5*
1Department of Mechanical Engineering
2Department of Chemical Engineering
3Department
of Mining, Metallurgical, and Materials Engineering
4Energy Engineering Program
5Environmental Engineering Program
College of Engineering, University of the Philippines Diliman
Quezon City 1101 Philippines
Waste disposal is an important issue that needs to be addressed, not only for health and
environmental reasons but also for its social and economic impacts. Three important waste
streams that contribute to the growing amount of wastes generated come from medical,
industrial, and electronic residual wastes. These residual wastes are usually just being dumped
or disposed of in sanitary landfills. Apart from finding solutions to these environmental
waste problems, these wastes can be a possible source of energy that can support our energy
sustainability. In this study, three different waste streams, medical, industrial, and electronic
wastes in Metro Manila – the capital region in the Philippines – were profiled and investigated
for their potential as waste-to-energy (WTE) feeds. The daily generation, types of wastes, and
heating values were studied. The total generated daily waste for medical wastes, hazardous
industrial wastes, and residual electronic wastes that have a potential for WTE was about
143,834 kg/d or about 52,500 tons/yr. Its total energy potential was about 4,727 GJ/d. These
large amounts of residual WTE feeds can potentially support daily energy needs, as well as
mitigate problems associated with the typical disposal of these hazardous and residual wastes.
Keywords: electronic waste, industrial waste, medical waste, waste disposal, waste-to-energy
INTRODUCTION
Environmental problems and socio-economic impacts
due to mismanaged wastes are some of the big issues
and concerns, especially in developing countries. As a
consequence, littered and illegally dumped solid wastes
*Corresponding Author: rmcervera@up.edu.ph
become increasingly visible in streets, private and public
lands, rivers, lakes, beaches, coastal areas, and even
offshores. Mismanaged solid wastes may have been
causing declining health, contamination of soil and water
due to degradation of illegally dumped solid waste, and
declining tourism due to visible littered wastes (Rushton
2003). One of the reasons for mismanaged solid wastes
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is the lack of solid waste disposal facilities. Apart from
environmental concerns, in the Philippines – for example
– the increasing demand for energy and energy security
is also one of the important issues that the Philippine
government needs to address. Hence, there is a crucial
need to manage and build facilities that can reduce wastes
volume and at the same time taking advantage to utilizing
the energy from waste to generate electricity that can
support the energy supply.
WTE is considered as one of the sustainable means of
waste management and promising technologies for future
renewable energy sources (Kothari et al. 2010; Kumar and
Samadder 2017; Eddine and Sallah 2012). Common WTE
technologies such as incineration, pyrolysis, and gasification
typically utilize municipal solid wastes as raw material feed
(Kumar and Samadder 2017; Tan et al. 2015; Agaton et al.
2020). Moreover, wastes feed such as agricultural or biomass
wastes are also considered as potential renewable energy feed
sources (Kothari et al. 2010). However, in order to realize
and sustain further this WTE as a future renewable energy
source, other potential wastes are needed.
Apart from municipal solid wastes, other major wastes that
have potential as WTE feed sources are those coming from
medical facilities, hazardous wastes from industries, and
different residual electronic wastes. Most of the residual
wastes from these waste streams, after segregation and
treatment, usually just end up in storage facilities – or
worst – in landfills. For medical wastes, for example, the
global wastes generated surge and increase manifolds
during the COVID-19 pandemic, which adds up to our
waste problems (Sarkodie and Owusu 2020; Klemes et
al. 2020). Hazardous industrial wastes, on the other hand,
such as paints and used oils and grease after treatment just
end up also in storage facilities or in landfills. Moreover,
for electronic wastes – after segregating and recovering the
recyclable materials – the residual electronic wastes also
are just being disposed of in landfills. These three different
wastes streams – instead of adding to environmental waste
problems – may have potential benefits as a WTE feed,
which can help not only in managing these wastes but also
to provide alternative source and energy supply support.
There are various reports on the waste management,
treatment, or disposal technologies for medical wastes
(Zhao et al. 2009; Cai and Du 2020; Caniato et al. 2016;
Khan et al. 2019; Hong et al. 2018; Jang et al. 2006; Nema
and Ganeshprasad 2002); however, only very limited
reports were published on the potential of medical waste
for WTE so far (Bujak 2009; Singh and Khosla 2017;
Manegdeg et al. 2020). Bujak (2009) reported the energy
efficiency of an incinerator for medical waste; however,
no detailed profiling and elementary composition of
medical wastes were provided, and the study was focus
mainly on the experimental analysis of useful energy flux
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and coefficient of energy efficiency of an incinerator for
medical waste combustion from a certain hospital facility.
Similarly, Singh and Khosla (2017) reported and focus
their study on the comparative performance of materials of
medical waste incinerators. The profile of medical waste
and compositional study were also not reported. Manegdeg
et al. (2020) reported medical waste characterization
and electricity generation using pyrolyzer-rankine cycle;
however, the scope of the study was only limited to specialty
hospitals in one particular city. On the other hand, there
are also very limited reports for the WTE potential of
hazardous industrial wastes (Eddine and Sallah 2012; Lupa
et al. 2011). Eddine and Sallah (2012) reported the use of
commercial and industrial waste in energy recovery systems
in the UK; however, no waste profiling was done and only
reported the energy generation potential taken from waste
samples at waste management sites. And for residual
electronic wastes as potential feed for WTE, there are none
published yet up to date to the best of our knowledge.
In this study, waste profiling and characterization of
medical, hazardous industrial, and electronic wastes were
conducted in Metropolitan Manila, Philippines. The waste
generation and profile for each of these waste streams were
investigated and its potential as feed for WTE.
MATERIALS AND METHODS
Medical Wastes Analysis and Characterization
In this study, guided by the categories from the Department
of Health (DOH) Memorandum No. 2012-0012 and the
2019 National Health Facility Registry listing in the
Philippines, the total number per medical facility category
was first obtained. There are five major medical facility
categories – namely, general hospitals, specialty hospitals,
stand-alone facilities, rural health centers, and barangay
health centers. Within the database of the category, the
selection of the sampling sites had been randomized,
with certain consideration that the samples had been
dispersed throughout the metropolis. This was to ensure
that representation of a wide distribution of populations
and various districts will be presented in the study. In this
report, only general hospitals and those specialty hospitals
were considered. Rural health centers and barangay health
centers were also investigated; however, initial studies
from these facilities showed varying and very minimal
daily wastes. Stand-alone facilities such as dialysis centers
and dental clinics were also excluded.
For the sampling sites, different hospitals were first classified
in accordance to DOH Memorandum No. 2012-0012,
which classifies medical facilities under various categories
– each based on their general function, bed capacity, service
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capabilities, and training hospitals. According to functional
capacity, general hospitals may be classified based on their
bed capacities, which are ranked from Level 1 to Level 4
hospitals. These levels account for their capacity to treat
patients based on their needs – from simple to complex
treatments. Specialty hospitals are sub-categories also
considered in the functional capacity category.
Waste profiling from the randomized different hospital
sites was conducted during the pre-COVID-19 pandemic
between November 2019 up to February 2020. Three
hospitals for Levels 1 and 2, three hospitals for Levels 3
and 4, and four specialty hospitals were considered as the
sampling sites wherein the last three specialty hospitals
were taken with reference to our previous study (Manegdeg
et al. 2020). These hospitals account for about 6% of
the total general and specialty hospitals in Metropolitan
Manila. The data collection involved sending a request to
a particular hospital and meeting with a pollution control
officer to discuss pertinent data and outcomes for the data
collection in their facility. Appropriate health protocols
were observed during the collection of waste materials
by wearing proper personal protective equipment. Daily
gathering of data on the general and infectious wastes
was done and lasted for eight days. On both waste types,
all bags of the same waste type generated within the day
were weighed to obtain the total weight. Total generated
waste per day in a facility was obtained from the hospital
waste data weighed every day after collection, and then
the daily average was taken for the eight-day generation.
To identify the individual weights per waste material, three
bags of the total bag number per day of the general waste
types from all the hospitals were segregated and weighed
according to the waste material. This method was applied
due to the constraints and protocol of the hospitals involved.
On the other hand, for infectious waste – due to health
hazards – only the estimation was done on the types and
quantity via visual inspection of the waste bag. The weight
of the waste bag was determined using a weighing balance.
Further verification on the reliability of this approach was
done through laboratory weighing of clean samples and
multiplied by the respective number of the samples during
the inspection, including some correction factor to account
for other matters such as dirt, moisture, and among others
that added up to the actual weight. Heating values of
general medical waste were compared from literature values
(Sharuddin 2016; Erdincler and Visilind 1993) and those
medical wastes that were infectious were obtained using
a bomb calorimeter by using a representative clean waste
material sample since literature values are not available.
Industrial Wastes Analysis and Characterization
For hazardous wastes, only the collection of secondary
data was conducted due to legal and safety restrictions
in handling these kinds of wastes. The hazardous
waste types were based on Chapter 2 (Classification of
Hazardous Waste) of the Department of Environment
and Natural Resources (DENR) Administrative Order
(DAO) No. 2010-22. This list classifies hazardous wastes
into 56 types based on a combination of industry source,
main constituents, and the kind of medium the waste is
contained in. The final list of waste types, as shown in
Table 1, was selected using the inclusion and exclusion
Table 1. Hazardous waste types for WTE (DENR–EMB DAO 2013-22).
Class
Description
Waste number
F. Inks/ Dyes/ Pigments/ Paint/ Resins/ Latex/ Adhesives/ Organic sludge
Solvent-based
Includes all solvent-based wastes that also meet one or more of
the subcategories
F601
Inorganic pigments
Includes all wastewater treatment sludge from the production of
inorganic pigments
F602
Includes all grease wastes generated from establishments such
as industrial, commercial, and institutional facilities
H802
Used industrial oil, including sludge
I101
Vegetable oil, including sludge
I102
Tallow
I103
Oil-contaminated materials
I104
Expired pharmaceuticals and drugs stocked at producers’
and retailers’ facilities that contain hazardous constituents
harmful to the environment such as antibiotics, veterinary and
phytopharmaceuticals, among others
M503
H. Organic wastes
Grease wastes
I. Oil
Used or waste oil
M. Miscellaneous wastes
Pharmaceuticals and drugs
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criteria. Inclusion criteria for hazardous waste types are
those hazardous wastes that have prior literature to support
their use in waste to energy technologies while those
excluded are hazardous waste types such as medical and
hospital wastes, electronic wastes, hazardous wastes that
do not have clearly defined constituents, hazardous wastes
that have known chlorinated components, and hazardous
wastes that have constituents belonging to the DENR
Priority Chemicals List.
Based in DAO 2013-22, also known as the Revised
Procedures and Standards for the Management of
Hazardous Waste (Revising DAO 2004-36) – which
provided a procedural manual for the technical
requirements and standards for generators of, transporters
of, and TSD (treatment, storage, and disposal) facilities
for hazardous waste under Section 2 on the classification
of all hazardous wastes – the following types viable for
waste to energy conversion were considered.
Due to the dangers that hazardous wastes pose to human
health, actual waste accounting in industrial settings was
not done. Instead, self-monitoring report (SMR) data –
which contain the quarterly generation of hazardous waste
in Metro Manila from the 1st quarter of 2017 to the 4th
quarter of 2019 – were obtained from the Environmental
Management Bureau (EMB). The average yearly generation
was used in subsequent analyses. Hazardous waste types
that have not been used in WTE applications based on
prior literature were not included. The calorific value of
the selected waste types was taken from known literature
values for a specific industrial waste material (Muniz 2003;
Trabelsi 2018; El-Mekkawi 2020; Balcik-Canbolat 2017;
Barişçi and Salim Öncel 2014; Filippis 2012).
Electronic Wastes Analysis and Characterization
For electronic wastes (e-wastes), there are basically two
facilities that handled these wastes: 1) TSD facilities and
2) junk shops. According to Metro Manila Solid Waste
Management Report, a lot of junk shops are not registered
with the local government unit (LGU) (Varey et al. 2003).
Given this amount of undocumented junk shops, the profiled
junk shops in the metropolis were only limited to those which
are registered with their respective LGUs. On the other hand,
for TSD facilities, the DENR lists a total of 24 TSD facilities
in Metro Manila as of January 2020. Of these 24, only two
are facilities that handle both classifications of hazardous
wastes that are from electronics wastes.
To sample the junk shops in Metropolitan Manila, the
metropolis was first divided into quadrants – namely,
north, east, west, and south quadrants – which was based on
the Oplan Metro Yakal Plus of the Metro Manila Disaster
Risk Reduction and Management Council (Varey et al.
2003). In this study, a combination of sampling techniques
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was used in the selection of junk shops. Proportionate
stratified sampling was initially done with a sampling
percentage of about 3%. Then, to finally determine the
respondents, convenience sampling was employed on the
junk shops within the quadrants or the strata. Proportionate
stratified sampling was chosen to proportionate the size of
the number of junk shops in the quadrants when viewed
against the total number of junk shops. It also provides
better precision than a simple random sample of the same
size. Convenience sampling was then chosen due to the
concealing of information by some LGUs on the junk
shops in their cities or municipalities, thus restricting the
use of proportionate stratified random sampling.
The data gathering of this research started with the
application of the sampling procedures to the profiled
e-waste handling facilities to determine which of the
facilities will be considered sampling sites. The chosen
facilities were then contacted or visited on-site to request
the facility to take part in the study. The communication
between the researchers and the sampling sites included
the rationale (purpose, objectives, significance of the study,
scope, and limitations) and the general methodology of
the research. Once the facility agreed on taking part in the
study, the people who are in charge or are knowledgeable
with the facilities’ electronic waste management were
first interviewed about the specifics of the facilities’
e-waste flow. The involved personnel was asked about the
processes involved in the facilities’ daily operations, from
the reception of the electronics up to its waste disposal,
which involved the residual wastes. The facilities then
accomplished the eight-day residual waste data collection
forms. Data gathering was facilitated by using two data
collection forms that allowed the researchers to evaluate
the performance of the facilities in gathering e-waste
materials from sources through their waste collection
schemes prior to and during the eight-day data gathering
period. The first form allows the researchers to obtain
information pertaining to the operation of the sample
facilities. This includes the usual waste stream flow of
e-waste materials, as well as cash flow from buying and
selling of dismantled products. The second form focuses
on obtaining relevant information related to the inflow
and outflow of pertinent materials or appliances, as well
as the outflow of residual waste materials being collected
by waste collectors for dumping to landfills. Similar to
medical waste, the daily generated waste was averaged
from the eight-day data collection. The characterization of
the electronic residual wastes started with the segregation
by material or component type and the identification of
the specific e-waste it was originally from. The residual
samples were also weighed to determine their weight
relative to that of their e-waste source. The material type
of the residuals was then identified, and heating values
were taken using a bomb calorimeter.
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RESULTS AND DISCUSSION
Medical Waste Generation and Waste Profile
Medical waste is defined as any waste material in solid or
liquid form generated or produced by diagnosis, treatment,
or immunization of human beings or animals, medical
research, pathological testing, and waste from minor or
scattered sources (DOH 2012). The waste management
manuals given by the DOH discussed types of healthcare
wastes (HCWs) produced by the medical facilities and
guidelines to proceed with its handling, treatment, and
storage. There are several categories or types of HCWs
such as: 1) non-hazardous or general, 2) infectious, 3)
sharps, 4) pathological and anatomical, 5) pharmaceutical,
6) chemical, and 7) radioactive wastes. Among these types
of medical wastes, the focus was on the medical waste
generation for general and infectious wastes.
General wastes are comparable to domestic wastes. This
type of waste does not pose a special handling problem
or hazard to human health or to the environment. General
wastes can include both recyclable and non-recyclable
materials. Such materials for recyclables involve paper
and plastic products while non-recyclable wastes include
wastes such as polystyrene (PS) based materials.
Manegdeg et al.: Profile and Energy Conversion Potential
of Wastes in Metro Manila, Philippines
Materials are considered infectious wastes if they have
pathogens and have enough to cause diseases. These
may include but are not limited to the following: clinical
laboratory instruments and materials containing bodily
fluids or those in contact during clinical procedures such
as catheters and tubing.
Figure 1a shows an example of the HCW handling for
infectious waste and non-biodegradable general waste,
as stated in the DOH Healthcare Waste Management
Manual (DOH 2012). For infectious medical wastes, the
flowchart shows that treatment of these waste can either
be done on-site or off-site; however, these wastes still
ends up and disposed of after treatment. On the other
hand, for non-biodegradable and non-recyclable general
waste, these wastes are directly collected, transported, and
disposed of in landfills.
The waste profiles of general and infectious wastes
before the COVID-19 pandemic are shown in Figures
1b and c. Figure 1b shows that there were ten general
waste material types found on medical facilities –
namely, the low-density polyethylene (LDPE) plastics,
textiles, plastic cups, cans, PS, glass, polyethylene
terephthalate (PET) plastics, high-density polyethylene
(HDPE) plastics, papers, and rubber. Based on the chart,
Figure 1. Medical waste stream and waste profile: a) flowchart of infectious and general (non-biodegradable and
non-recyclable) wastes; b) daily general waste; c) daily infectious waste.
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the top four types of general waste generated from
medical facilities are the PETs (34.9%), papers (22.5%),
cans (12.2%), and LDPE plastics (10.4%). Other waste
materials gathered from these facilities were commonly
used materials such as rubber, glass, PS, and textiles.
On the other hand, for infectious medical wastes, only
an estimation of infectious waste material composition
was done in the study as infectious waste materials
are dangerous even when exercising caution. For
this study, estimation was done by peeking through
the waste container. Figure 1c shows the waste
composition generated for infectious wastes. From
these estimations, diaper, gloves, and masks comprised
the highest contribution in the amount of infectious
wastes generated. For the WTE feed, only combustible
waste materials were included in the calculation for the
total generated daily waste for energy potential, thus
excluding non-combustible wastes such as glasses and
cans. The total generated daily combustible medical
wastes in Metropolitan Manila were about 41,174
kg/d and about 33,732 kg/d for general and infectious
medical wastes, respectively, with a total of about
74,906 kg/d. This total medical wastes generated per
day was obtained based on the average gathered data
from the hospitals.
In general, the total medical waste characterization was
based on all waste sources gathered from the hospitals to
get the total composition of the waste stream. Although
hospitals differ in function and capacity, the majority of the
Manegdeg et al.: Profile and Energy Conversion Potential
of Wastes in Metro Manila, Philippines
general wastes or material types generated were similar,
but the amount of the wastes generated varied depending
on how large the hospital was. Moreover, the production of
infectious wastes can vary between general and specialty
hospitals due to function.
Hazardous Industrial Waste Generation and Waste
Profile
Metropolitan Manila has the highest number of
manufacturing industries in the Philippines. At 19,291
facilities, the capital region hosts 17% of the country’s
total number of factories and manufacturing plants (PSA
2018). The government categorizes establishments based
on the number of employees. There are currently four
categories – namely, micro, small, medium, and large
enterprises – which correspond to establishments having
1–9, 10–99, 100–199, and more than 200 employees,
respectively. These industries are the main source of
hazardous industrial wastes.
Figure 2 shows the flowchart of the collection, transport,
treatment, and disposal of hazardous wastes based on
the TSD facility category. Category A covers facilities
that perform onsite treatment and disposal of hazardous
wastes. These facilities also employ treatment methods
from Categories B–E and G. Category B covers facilities
that utilize thermal methods transforming the physical
and chemical characteristics of the hazardous wastes
prior to disposal. Category C covers facilities that collect
hazardous waste for final disposal to sanitary landfill
Figure 2. Collection, transport, treatment, and disposal of hazardous wastes based on the TSD facility category.
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or surface impoundments. Category D covers facilities
that employ the recycling and reprocessing of hazardous
wastes. It includes recovery of materials such as used
oil, solvents, metals, etc. It also reprocesses materials for
fuel to energy. Category E covers facilities that conduct
chemical treatment methods such as encapsulation and
immobilization transforming the physical and chemical
characteristics of hazardous wastes prior to disposal.
Category F covers facilities that store hazardous wastes
prior to thermal or chemical treatment, disposal, or export.
Category G covers facilities that conduct the draining of
PCB oil and dismantling of PCB-containing equipment
prior to treatment and disposal (DAO 2013-22).
For the hazardous industrial wastes, eight types were
considered from the 56 hazardous waste types excluding
the medical and electronic wastes and based on the
following screening criteria: hazardous wastes that do
not have clearly defined constituents, those that have
known chlorinated components, and those that have
constituents belonging to the DENR Priority Chemicals
List. The hazardous industrial wastes profile is shown
in Figure 3. The data from this figure were gathered and
analyzed based on the SMRs submitted to DENR by
Manegdeg et al.: Profile and Energy Conversion Potential
of Wastes in Metro Manila, Philippines
the industrial plants and from the Philippine Statistics
Authority (PSA). The bulk of the average daily generated
waste from the studied industrial wastes was attributed to
I101 (61.6%), which are wastes coming from petroleum
refining operations and manufacturing plant wastes such
as used industrial diesel and lubricants. The total industrial
hazardous wastes generated from these types of wastes
were about 59,300 kg/d.
Electronic Wastes Generation and Waste Profile
E-wastes or waste electrical and electronic equipment is
defined as any end-of-life equipment that is dependent
on electrical currents or electromagnetic fields in order to
work properly (Grant et al. 2013). There are basically three
domestic sources of e-wastes: households, institutions, and
industries (Yoshida et al. 2016) that are handled by the
two major sectors of e-waste handling facilities: the TSD
facilities and junk shops. The general e-waste management
and disposal flow is shown in Figure 4.
TSD facilities typically cater to private individuals,
businesses, and companies. They usually handle industrial
e-waste as well as e-waste coming from institutions. These
Figure 3. Hazardous industrial wastes profile. The total generated hazardous industrial waste that has potential
as energy feed is about 59,342 kg/d.
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Figure 4. General E-waste disposal management.
entities contract TSD facilities to collect, treat, and dispose
of their waste safely. Since they do not entertain walk-in
waste collection and trading like other facilities such as
junk shops, e-waste inflow is not regular but rather on a
job-order basis. After dismantling electronic equipment,
salvaged metal and plastic components are shipped off to
private melting companies. TSD facilities dispose of their
residual waste in the general waste collection care of the
local government.
Junk shops, on the other hand, mainly handle household
e-wastes coming from local residential areas. Junk shops
with higher buying capital may participate in auctions
done by companies, which puts them in competition
with TSDs. E-waste may be sourced by members of the
community, also known as dismantlers, that collect waste
door-to-door. However, due to the relatively small volume
of e-wastes brought by dismantlers daily, the junk shops
accumulate scraps and e-wastes prior to selling to the
consolidators. Metal and plastic components, on the other
hand, are taken by private melting companies; electronic
parts are auctioned off to private buyers while residual
waste is transported to landfills. This, of course, may not
always be the case since some e-waste still directly makes
it to landfills, which calls for more stringent policymaking.
Illustrated in Figure 4 is the general waste flow for both
facilities. The figure indicates the sources of e-waste
(blue), the handling facilities (red), actions done (yellow),
and products.
From the flowchart, TSD facilities and junk shops are
the facilities that process e-waste. Essentially, TSDs are
the facilities where hazardous wastes are transported,
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stored, treated, recycled, reprocessed, or disposed of
(DAO 92-29), while junk shops are defined as the
buyers of the scraps coming from dismantlers (Yoshida
et al. 2016). Electronics in e-waste handling facilities
are dismantled and different components are sorted. In
this study, e-waste components are classified as either
recyclable or residual. Recyclable components are those
plastic and metal components that are sold to recycling
and smelting companies. These also include electronic
components that are typically repaired and reused by
private buyers. Anything that could not be repurposed or
recycled is considered a residual component of e-waste.
For the purpose of waste to energy conversion, only the
residual components of e-waste are considered.
TSDs and junk shops reported an average amount of
103.06 kg of e-waste per day per facility, which composed
of recyclable and residual components weighing 81.62 kg
and 21.60 kg, respectively, as shown in Figure 5a. Daily
e-waste collection was estimated at 120,168 kg – made
of 95,052.86 kg of recyclable components and 25,115.10
kg of residual components. This amounts to at least a
total of about 43,880 metric tons of e-wastes – made of
34,709 metric tons of recyclable components and 9,171
metric tons of residual components – each year in Metro
Manila alone.
Since TSDs mainly handle e-waste from institutions and
industries while junk shops handle those coming from
households, it is expected that the type of e-waste they
collect would differ. However, due to recent developments
where a private recycling group having similar practices
to junk shops has just been established as a TSD facility
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in Metro Manila, the waste types are not so different.
Illustrated in Figure 5c are the different types of e-waste
in kg in a typical e-waste handling facility in a day. It
can be seen that refrigerators, air conditioning units, and
old box-type television sets make up the most of e-waste
collected based on weight with each being collected at
about 21.95, 13.51, and 13.47 kg/d, respectively. Each
e-waste type was dismantled and the residual components
were determined. From the dismantled e-waste, as shown
in Figure 5a, 79.1% are recyclable while 20.9% are those
residual e-wastes that will be disposed of and end up in
landfills. On the other hand, the residual components of
the different e-waste types can be classified according to
material type, which was found to be materials made up
mostly of polyurethane, ABS, PVC, and non-combustibles.
From the 21.6 kg of residual e-waste collected every day
in each facility, 58.2% are not combustible as these are
main components made from glass. The remaining 9.0 kg
that is combustible may be valuable for energy conversion
Manegdeg et al.: Profile and Energy Conversion Potential
of Wastes in Metro Manila, Philippines
purposes. Taking out the non-combustible components,
the composition of a possible feedstock coming from
a daily influx of e-waste for a single waste to energy
conversion facility is composed of 79.5% of polyurethane,
11.5% ABS, and 9.0% of PVC, as seen in Figure 5b.
Heat Maps and Energy Potential of Medical,
Industrial, and Electronic Wastes
Figure 6 shows the daily waste generation heat maps in
Metro Manila for medical, hazardous industrial waste, and
residual e-wastes. Quezon City, which is the largest city in
Metropolitan Manila, showed the highest amount of daily
generated wastes among the other cities. Based on these
heat maps, a possible potential WTE facility can be built.
Table 2 revealed the daily generated wastes for the three
waste streams, potential combustible waste compositions,
and their energy potential. The total energy potential for
each waste stream was calculated by multiplying the
Figure 5. E-waste profiles: a) average weight (kg) of residual and recyclable components of each e-waste handling
facility per day; b) composition of the daily average residual wastes; c) average total weight (kg) of different
types of e-waste per day per facility.
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Manegdeg et al.: Profile and Energy Conversion Potential
of Wastes in Metro Manila, Philippines
Philippine Journal of Science
Vol. 150 No. 4, August 2021
Figure 6. Heat maps of daily generated wastes in Metropolitan Manila, which have the potential for WTE: a) medical, b) hazardous
industrial, and c) residual e-wastes.
Table 2. Daily generated wastes profile and energy potential of medical, hazardous industrial, and residual electronic wastes.
Waste stream
Total waste generated in
Metro Manila (kg/d)
Component
composition/ material
type (weight %)
Average calorific value,
HHV (MJ/kg)
Total energy potential,
GJ/d (Metro Manila)
General medical waste
41,174
LDPE (12.2%);
PP (11.6%);
PS (9.2%);
PET (40.3%);
HDPE (0.1%);
paper (26.6%)
29.3
1,208
Infectious medical waste
33,732
Diaper (46.4%);
syringe (1.9%);
storage aids (7.1%);
mask (10.9%);
gloves (18.3%);
dressing (15.4%);
23.6
788
Residual electronic waste
9,585
Polyurethane (87.4%);
UBS (12.6%)
25.5
244
Hazardous industrial
waste
59,342
F601 (3.6%);
F602 (4.2%);
H802 (11.5%);
I101 (61.6%);
I102 (5.9%);
I103 (0.01%);
I104 (3.8%);
M503 (9.2%);
41.9
2,487
Total
143,834
–
–
4,727
average calorific value with the total waste generated.
The generated daily wastes in Metropolitan Manila for
medical, industrial, and residual electronic wastes that
have a potential for WTE were about 143,834 kg/d (143
tons), which has an energy potential of about 4,727 GJ/d.
This is approximately comparable to about 127 m3 of fuel
620
gasoline or 160,000 kg of charcoal for such daily energy
potential (i.e. gasoline with 46.4 MJ/kg HHV, charcoal
with about 29.6 MJ/kg HHV). From this energy-fromwaste potential, an estimation of its electricity generation
potential by conventional pyrolysis is about 45 MW/d.
With this electricity generation potential, if modular WTE
Philippine Journal of Science
Vol. 150 No. 4, August 2021
Manegdeg et al.: Profile and Energy Conversion Potential
of Wastes in Metro Manila, Philippines
can be built, this can already help and support some of
the electricity needs in the metropolis. The appropriate
and viable type of WTE technologies that can utilize
these waste feeds – considering as well potential hazards
and mitigation measures, and the details of the electricity
generation potential (e.g. pyrolysis) – will be reported
elsewhere. In addition, financial and economic feasibility
and socio-economic impacts for a WTE technology will
be reported and discussed in a different paper. Thus, with
the efforts and push for non-coal energy generation, such
potential energy-from-waste can be viable support to
existing renewable energy sources in addition to helping
solve the lack of disposal facilities – as well as problems
associated with the generated wastes coming from medical,
hazardous industrial, and residual electronic wastes. Since
waste streams from medical wastes, hazardous industrial
wastes, and residual electronic waste – will be almost
similar to other cities. Except for the generated amount
of these wastes depending on the number of facilities or
industries in a particular city, the waste profiling and the
feasibility of utilizing these wastes into useful energy
can be a source of reference information and other cities
may consider the WTE technology as a means for waste
disposal and energy source.
in sanitary landfills, can already add to about 52,500 tons
annually. The total daily energy potential of the three waste
streams was about 4,727 GJ/d. Future study may include
the formulation of enabling policies and the environment
in order to realize WTE as alternative waste disposal and
potential of medical, hazardous industrial, and residual
electronic wastes for WTE.
In this study, the following are recommended for waste
profiling and future studies of the three investigated waste
streams: 1) inclusion of smaller health facilities, such
as barangay and rural health centers, and other standalone facilities such as dental clinics can be investigated
since the scope in this study was limited to the hospital
facilities as they produce the most significant amount of
wastes; 2) for e-waste, due to informal economy nature
of junkshop facilities, only registered junkshops were
considered as unregistered junkshops may increase the
daily residual e-waste generated and subject for further
investigation; and 3) direct investigation can be pursued
for waste generation by industrial facilities that produce
hazardous wastes. The analysis may be able to further
characterize their residual output to accurately check what
waste materials are being produced in certain industries
and their potential for WTE.
AGATON CB, GUNO CS, VILLANUEVA RO,
VILLANUEVA RO. 2020. Economic analysis of
waste-to-energy investment in the Philippines: a real
options approach. Applied Energy 275: 115265.
CONCLUSION
The waste profiles and WTE potentials of medical,
hazardous industrial, and residual electronic wastes
in Metro Manila, Philippines were investigated. The
generated daily residual wastes for medical wastes
composed of general and infectious wastes were about
74,906 kg, hazardous industrial wastes were about 59,342
kg, and residual electronic wastes were about 9,585 kg.
These residual wastes, if just being dumped or disposed of
ACKNOWLEDGMENTS
This project is financially supported by the Philippine
Senate Committee on Energy and the Energy Research
Fund of the Office of the Vice-President for Academic
Affairs, University of the Philippines Diliman. The authors
also would like to acknowledge the research assistance
of Jan Carlo Palomares, Christine Mae Macalisang, Jessa
Hablado, Pearl Diamansil, Ricardo Sirot Jr., Vince Carlo
Garcia, Vince Roi Alvarez, Steven Peabody, Anjanette
Canales, Nivard Elijah Daliva, and Gin Mig Gallardo.
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