They are trained using a buddy system, which benefits staff with disabilities as well as able-bodied ones, says Ms Lilian Teoh, a manager for customer service, learning and development at Han's Group.
"Non-disabled staff can look out for staff with disabilities, who may let their buddy, but not other staff, know if they are not feeling well, for instance," she says. "It makes the rest of the team more compassionate. We see team members offering help to our workers with disabilities without being told."
In Singapore, a lot more can be done to change mindsets in corporate companies, say disability support groups.
Movement for the Intellectually Disabled of Singapore (Minds) helps to train and secure employment for PWDs.
Ms Evelyn Leong, director of corporate development and outreach at Minds, says: "Our clients are very good at doing work that is repetitive. They're enthusiastic and enjoy working.
"The biggest hurdle is people thinking that those with special needs cannot fulfil their work tasks."
Minds regularly organises internships in industries as diverse as laundromats, supermarkets, hardware shops and car wash facilities in petrol stations for its clients starting from the age of about 16.
By around age 19, some PWDs can be guided towards working in sheltered workshops that cater to them, doing work such as packing, retail, baking and making crafts.
Others are placed in the general labour market, where they are mentored and supported by job coaches from Minds who ensure that they are not stressed in their new environment or check that they are able to take public transport to work.
The Government also runs schemes to help firms that hire those with disabilities. These include the Open Door Programme, which provides training grants for companies to develop customised programmes for persons with disabilities.
But while funding is available, the low employment rate for PWDs suggests other barriers.
Mr Chua, managing director of Adrenalin, says some PWDs seeking employment need to build their interviewing and other soft skills.
"Some are not able to express themselves. I have received e-mails such as one which read: 'Do you have a job? I am deaf," he says.
He grants interviews to anyone with special needs who approaches Adrenalin for work. On average, he hires one out of every 10 PWDs he interviews, he says.
Having an integrated workforce makes sense when there are labour shortages.
At Holiday Inn Singapore Orchard City Centre hotel in Cavenagh Road, where 12 per cent of the more than 200 staff are PWDs, adjusting to the different ways of communication of some PWD employees, some of whom have intellectual disabilities or autism, is a worthwhile investment.
This includes getting managers to give more regular feedback, supervision and encouragement to PWD staff compared with other staff, or breaking down instructions into simpler components, says Ms Tresille Melson, the hotel's human resources director.
Having PWD employees, who work in departments such as housekeeping, "supports us in our manpower issues", says Ms Fauziah Ali, an executive housekeeper at the hotel, adding that one PWD worker has been there for about 20 years.
Mr Lee Kwang Hee, 42, a cleaner at the hotel who has Down syndrome, enjoys his work.
His younger brother, engineer Lee Kay Sua, 39, says: "My brother is very responsible. He wakes up at about 4.30am and takes a 11/2-hour bus ride at 5.30am to get to work. He is always early."