INGENIEUR
Table 4: Elemental Analysis of Bottom Ash
from Westfield Power Plant and
Malaysian Power Plant
ELEMENTS
WESTFIELD
PLANT
(µg/mg)
MALAYSIAN
PLANT
(µg/mg)
Chlorine <0.001 <0.001
Sulfite 0.13 <0.5
Total solids 99.9 89.6
Cadmium 1.4 <1.5
Thallium 0.4 <1.5
Mercury 1 <0.1
Antimony 1 <1.5
Arsenic 90 <1.5
Lead 73 <1.5
Chrome 220 <1.5
Cobalt 45 8.1
Copper 146 <1.5
Manganese 200 ND
Nickle 140 <1.5
Vanadium 277 6.9
Tin 10 <1.5
Source: IOP Conf. Ser.: Mater. Sci. Eng. 160
012056
level of the two countries, EQA 1974 for Malaysia
and Environmental Damage Act for Germany. This
physical chemical analysis and data provides
substantial scientific evidence to support the use
of BA as an alternative source in the construction
industry to replace exhausted soil and sand.
GLOBAL PERSPECTIVE AND USAGE OF BA
From a global perspective, the possibilities of using
BA in the construction industry is widely applicable.
This is substantially proven by its physical and
chemical properties. Table 5 lists amount of BA
generated by the top three countries in 2017. In
comparison, Malaysia only generates 622,200 tons
of fly and bottom ash annually which are considered
low. The top countries generating BA have formed
an international network to promote, co-ordinate
Country (2017)
India
China
USA
Table 5: Top three bottom ash producer
in the world
Bottom ash (tonnes) / year
100 million
~ 60 million
10 million
Source: Bottom Ash bench mark study report
and educate the public on the uses of BA and its
environmental impact. Under the patronage of the
World Wide Coal Combustion Products Network
(WWCCPN; http://wwccpn.com/), the network
ensures coal industries work closely to mitigate
the challenges of using BA as an alternative raw
material.
WWCCPN encourages the wide use of BA in
civil engineering, agriculture, manufacturing, soil
rectification and other industries. BA is extensively
used in the US, Australia, China, India, European
countries, Russia, Japan, and South Africa. In
general, the European and developed countries
have not classified BA as a hazardous waste. BA
has been utilised for different applications such
as manufacturing tiles, bricks, roof tiles and
mineral wool. The cement industry uses BA in the
production of clinker to make cement. In Japan
for instance, BA has been used in construction
and road works as a filler and aggregator. Table
6 gives a summary of the applications of BA in
various countries that may serve as supportive
information and resources towards enhancing its
usage in Malaysia.
Apart from engineering applications, BA has
been used in agriculture as fertilizers and soil
conditioners to improve the pH and nutrients in
the soil. For instance, Taisei Kuogyou, a Japanese
company has invented a technology called Taisei
Soil System (TSS). TSS uses BA in soil absorption
fields that enhances upward movement and
siphon flow of wastewater. This system helps to
maintain aerobic conditions and reduce biological
demand (BOD) up to 98%. Treated water from
TSS is evaporated and used by the plant. The
usage of BA in various sectors has reduced the
environmental impact in areas such as mining,
stone quarries and soil excavation work.
66 VOL 82 APRIL-JUNE 2020