Main Page > Green Projects > Incense Smoke Reduction System
Endless streams of pilgrims make their way into Wong Tai Sin Temple every day and the air is thick with smoke and fume that triggered the temple looking into its environmental, health and safety (EHS) issues. Funding from the Environment and Conservation Fund in 2014 gave us the opportunity in the development of the “Incense Smoke & Odour Collect and Filtering System” and “Incense Burners”. Thus making us the first temple in Hong Kong equipped with such air pollution control system, commissioned system to January 2017.

Part 1: Incense Smoke & Odour Collection & Filtering System

Three arch-shaped “Incense Smoke & Odour Collection & Filtering System” with the Electrostatic Precipitator capable of removing over 80% of PM10 and PM2.5 particulates in the exhaust, are installed outside the Main Altar. Zeolite and activated carbon are used to remove VOCs by adsorption that eliminates over 60% of the PAHs and formaldehyde and in achieving zero black smoke release.

[The arch-shaped design while providing a full view of the area is also convenient for gathering incense sticks.]

Incense Burners
A total of four Dry Type Eco-Burners and one Wet Type Eco-Burner are installed in areas of the Main Altar, Three Saints Hall and Yue Heung Shrine. The Dry Type Eco-Burners use high temperature (over 300 degrees) to incinerate incense sticks. Ash and particulates in the hot flue gas are captured by the hot gas filter elements, and the hot gas being cooled down by the radiator, passes through the exhaust fan linked to an Electrostatic Precipitator for the removal of over 70% PM10 and PM2.5 particulates while eliminating over 60% of PAHs and formaldehyde, achieving zero black smoke release.

Addition to the two Electrostatic Precipitators is the Wet Type Eco-Burner equipped with a venturi scrubber and a recycle water tank, capable of processing large volume of incense sticks with an overall, more than 70% removal in fume and dust.

[The Wet Type Eco-Burner can handle 40kg of incense sticks per hour]


Part 2: Incense Ash Regeneration System

In Part I, it is mentioned that Absorption Filter is used for removing VOC. The filter material is transformed from the ashes generated by incense burning. The porous structure of this material is found to be an effective catalyst/absorbent for air purification as it provides a large surface area to trap and to degrade the pollutants with further oxidative degradation.
After chemical treatment, such as combing alkali, compressing and heating, incense ashes are transformed into suitable types of zeolites, which are then filtered, washed and dried to become malodour removal powders for air purification.
Zeolite produced can be moulded into different shapes. It can be used as filter materials, agriculture conditioners, construction mixture or other usages. The Yuen will use zeolite as the filter material in the Absorption Filter. In other words, the Yuen will convert the ash waste from incense into zeolite for absorbing the malodour and pollutants of incense.