Today the second scheduled industrial visit took place. The participants went to SembCorp Industries Ltd (Pre-Disposal Treatment Plant) and the Singapore Mint (the same visit as yesterday’s). Here is what happened for the first part of the trip.
SembCorp Industries – Pre-Disposal (of Waste) Treatment Plant
We were introduced to the Treatment Plant. Before the waste you created (i.e., rubbish) is being sent to the incineration plant or the landfill, the waste is being treated at this Pre-Disposal Treatment Plant.
This is a chart illustrating the process of the waste pre-disposal treatment:
Pre-Disposal Treatment Process of Waste
Weighing
At first, the rubbish truck comes here and passes through a special part of the road, which weighs the total weight of the truck together with the rubbish. Then the truck goes to the reception hall, where the waste is being deposited into the start of the treatment process. Then the truck goes out of the reception hall, and it is being weighed again, this time to check the remaining weight of the truck after all the waste is being deposited. A system at the back of the treatment plant then calculates the weight of the waste deposited and charges the trucks respectively.
Conveyor Belts
Now let us focus on the waste. The waste generally moves from place to place by a series of conveyor belts.
Conveyor Belt
Pressure Cookers – Why?
First the waste moves from the reception hall to pressure cookers. The waste is being “cooked” under a pressure of 300 kPa (considered very high pressure). The reason for doing this is to get rid of most of the germs to be ready for further treatment later.
The Turning Turbine-Sifter
Then the waste moves to the turbine – a place where the waste is being sorted out by the turbine into two groups – the bigger-sized waste and the smaller-sized waste. The smaller-sized waste consists of waste of around or less than 40 cubic centimeters (since the holes at the side of the turbine only allow things of that size to go through) – mostly food waste.
Turbine-Sifter
Sorting – Many Recyclables are found
Next, the waste is being transported by conveyor belts to a series of mechanical separators. Some of these are magnetic to separate the metals (magnetic ones only), which can be recycled instead of being thrown away. Other separators are of the same concept – to separate the recyclables.
Magnetic Separator for magnetic metals
The sorter part is not a mechanical machine – it is a group of workers (hired at a rate of SGD 6.00 per hour, we are told) who manually sift through the waste to find the other recyclables – those that machines cannot separate. The other recyclables include: cloth material (in other countries), plastic bottles and plastic bags, glass bottles, etc.
Conveyor Belt & Sorters hired
These recyclables are collected and sold to companies which recycle these materials. They actually cost a lot of money and most of the profit comes from these recyclables.
Finally, the rest of the waste reaches the end of the process. They are packaged and would be sent to incinerators and landfills.
The Pressure Cooker – How?
There are boilers around the place that provide the steam needed to “cook” the waste. Water is boiled – but how do you start the fire? The treatment plant actually collects woodchips to boil the water. Woodchips are collected through the waste – unwanted furniture provided by the population as well as unwanted wood from construction sites. They cost no money – the larger pieces of wood are broken down into smaller pieces using a hopper in the treatment plant.
posted @ 2:25 PM |
