1. SMALL-TOWN GIRL
Born in a small town called Kampar in Perak, she was abandoned at birth and brought up by an illiterate Chinese woman.
In 1977, the gutsy 16-year-old moved to Singapore and later secured a place in Hwa Chong Junior College.
But her young life took a turn for the worse when her grandmother fell ill and was hospitalised for nearly a year.
While sitting her A-level examinations, her grandmother died. Despite the tragedy, she clinched a spot to study chemistry at the National University of Singapore.
2. A NOSE FOR BUSINESS
When she moved here, she covered school fees and paid the rent by giving tuition. She even bought a motorcycle to travel faster to her students' homes.
On weekends, she worked as a promoter in department stores, peddling anything from cosmetics to smoke detectors.
Before entering university, she sold insurance, cosmetics, flower pots and souvenirs, among other things. With the profits, she struck up a partnership to run a canteen at construction sites - first in Katong, and then in Bukit Timah.
3. TAKING THE PLUNGE
After graduation, she joined industry giant Glaxo Pharmaceuticals as a chemist. The job allowed her to buy a condominium in Bayshore within months for just about $210,000 with no down payment.
After three years at Glaxo, she took the plunge. She raised funds by selling her condo unit for a profit, paid off her car loan and moved into a rented HDB flat.
And so at 28, Ms Lum set up her own business, Hydrochem, to sell water treatment products and systems.
She pooled together $20,000 in starting capital, which she used to set up shop in a cramped office in Tampines Industrial Park with one clerk and one technician.
Since firms in Singapore did not want the risk of dealing with someone new and unknown, she turned her attention to Malaysia and Indonesia.
4. FORBES LIST
In January 2001, on her 40th birthday, Hyflux launched its initial public offering on the Singapore Exchange's Sesdaq board. The stock rocketed, climbing 131 per cent.
Her clients included multinational companies such as STMicroelectronics, Hitachi Chemical Asia-Pacific, Sanyo Air-Conditioners Manufacturing, and even Jurong Bird Park.
That same year, her firm also won the tender to supply and install equipment for the country's first Newater plant.
In 2001, she became a Nominated Member of Parliament, and in 2003, she won Her World magazine's Woman Of The Year award.
By 2005, she had a net worth of over US$240 million, which earned her a place as the only woman on Forbes' South-east Asia Rich List. She was also ranked 17th in Forbes magazine's first Singapore rich list in 2006, and Forbes list of Asia's top 50 businesswomen in 2012.