She went on to study at Hwa Chong Junior College and graduated in 1986 with an Honours degree in chemistry from the Faculty of Science of the National University of Singapore.
After working for three years at Glaxo, she left in 1989 at the age of 28 to start up Hydrochem,[5] the precursor to Hyflux, with just SG$20,000 of capital, which she raised by selling her condominium and car.
[14] In May 2018, Hyflux applied to the Singapore High Court for a 30-day protection against creditor claims to allow the company time to reorganize its liabilities.
[17] In December 2022, it was reported that Hyflux was claiming damages exceeding S$690.6 million from Lum in a civil lawsuit alleging negligence and breach of fiduciary duty.
[18] On 17 November 2022, Lum, ex-CFO Cho Wee Peng and four other former board members were charged with violations of Singapore's Securities and Futures Act.
[19] On 5 May 2023, Singapore's State Court added three additional charges against Lum, citing violations of the Companies Act related to an allegation that she failed to exercise diligence in the discharge of her duties as a director.