Page 181 - New Trends in Eco efficient and Recycled Concrete

Recycling of waste glass in 6

construction materials

Jian-Xin Lu and Chi Sun Poon
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic
University, Kowloon, Hong Kong

6.1 Waste glass situation in Hong Kong

Due to the excellent characteristics of glass, such as optical transparency, chemical
inertness, high intrinsic strength and low gas permeability, glass containers are the
most commonly used form for packaging beverages. However, waste beverage glass
bottles have become a significant solid waste type in the municipal solid waste
stream in Hong Kong. From the Environmental Protection Department (EPD) report
[Environmental Protection Department (1997 2015)], the waste glass disposal and
recycling statistics in Hong Kong from 1997 to 2015 were collected and listed in
Fig. 6.1. Around 300 t of waste glass is generated daily and the majority of waste
glass are glass bottles. However, due to the lack of a local glass manufacturing
industry, the recycling rate of waste glass is very low (less than 10%).
By contrast, based on the European Container Glass Federation statistics
(European Container Glass Federation), the average recycling rate of container
glass in Europe reached 74% in 2014 and most of these were reused for
manufacturing recycled glass. Yet, due to the low residual commercial value of
waste glass containers, high logistics cost and the limited number of local recovery
outlets, at present, most of the waste glass containers generated in Hong Kong are
disposed of in landfills rather than being reused or recycled. Unlike other forms of
waste such as paper, wood or organic waste materials, waste glass bottles remain
stable after disposal of at landfills.
In order to enhance the recovery rate of waste glass beverage containers in Hong
Kong, the Hong Kong Government has promulgated a legislation to implement a
new mandatory Producer Responsibility Scheme (PRS) on glass beverage contain-
ers [Environmental Protection Department (2015)] to support waste glass recycling.
It has been estimated that about 50 kilotonnes/annum of waste glass beverage bot-
tles can be collected after the scheme is implemented. Nevertheless, efforts need to
be undertaken to explore future potential strategies with a view to broadening appli-
cations of recovered waste glass. The use of recycled glass materials in construction
is among the most attractive option because of the relatively large demand, lower
quality requirements and the wide potential applications in the construction indus-
try. The most common type of beverage glass containers used is soda-lime-silica
glass, which usually contains 10 20 mol% Na 2 O, 5 15 mol% CaO and
New Trends in Eco-efficient and Recycled Concrete. DOI: https://doi.org/10.1016/B978-0-08-102480-5.00006-3
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