A Chinese national accused of running a brothel out of a Brighton apartment was ordered held on $1 million bail yesterday after his defense attorney claimed the more than $55,000 in cash investigators found at his home was money his mother accumulated in part by redeeming bottles and cans.

Zhao Liu, 47, of Brighton, pleaded not guilty in Brighton Municipal Court to charges including trafficking a person for sexual servitude, deriving support from prostitution, maintaining a house of prostitution and keeping a house of prostitution.

Liu’s arrest Wednesday was the result of an 11-month investigation into the Highgate Street apartment where the brothel allegedly operated that involved cameras, a confidential informant and statements from customers, according to Suffolk District Attorney Daniel F. Conley’s office.

Assistant District Attorney Alyssa Tochka said members of the Boston Police Department’s Human Trafficking Unit observed as many as 10 men a day going into the apartment, where three women inside would charge between $140 and $160 to perform sexual acts.

Tochka said each of the women had a room with two beds — one for sleeping and one for work. A fourth bedroom in the apartment, she said, belonged to Liu.

Tochka said new women were brought in every three weeks. The three women who were there Wednesday when cops broke down the door were all in their 30s, she said, and were taken to the Family Justice Center to be interviewed by detectives.

Liu was arrested after officers spotted him trying to run out the back of the apartment, she said.

During a search of Liu’s apartment on Hopedale Street, investigators said they found Liu’s mother and $55,902 in cash. Liu’s defense lawyer, Kristin Wheeler, said the money they found belonged to his mother, who collects cans and bottles and redeems them.

“This was her life savings,” she told the court. “She doesn’t use banks. This is how she keeps her money … She’s very frugal.”

Wheeler said Liu came to the U.S. from China when he was 15 and he has worked in restaurants nearly his entire life.

Tochka said the case was being heard before a grand jury and was likely to end up in Suffolk Superior Court.