A total of 132 kilogrammes of solid waste was collected from the Chao Phraya River after just one hour of cleaning in an effort initiated by private and government organisations on Saturday.
The clean-up, normally conducted annually, was held on Friday and Saturday as part of an initiative to find strategies to improve the country's waste management system.
Cleaning was conducted along a 6km stretch of the river, from Rama III Bridge to Yodpiman Flower Market.
Among the participants were the Bangkok Metropolitan Administration (BMA), the Eco-Capitals Forum, volunteers from Mahidol University International College (MUIC) and Bangkok University International (BUI) and the Bangkok River Partners (BRP).
The latter is a co-op consisting of various stakeholders in the Chao Phraya River and surrounding areas, including hotels, retail complexes and transport operators.
As part of the cleaning event, volunteers and representatives boarded BMA cleaning boats, where they collected floating solid waste along the river's body and nearby riverbank. Other groups were also assigned to clean nearby roads.
In contrast with previous events, this year's accumulated solid waste was separated into seven different categories, including plastic and styrofoam, according to MUIC lecturer Ditthayanan Punyaratabandhu.
She said the data collected from separating the garbage into different types will assist future discussions with participating hotels to improve waste management, such as encouraging them to stop serving water in plastic bottles.
According to her, in one hour, BMA authorities and volunteers were able to collect more than 2,000 plastic bags, 700 plastic bottles and 600 plastic cups.
More than 1,300 foam pieces were also collected, she added.
"Most people wouldn't throw plastic bottles directly into the river, so when they see styrofoam or bottles in the water they don't think they are responsible for them," Ms Ditthayanan said.
"Even if people are not making the world dirtier today, every single piece of plastic that they throw away will stay in the environment for at least 450 years."
Suwanna Jungrungrueng, director-general of the BMA's Department of Environment, said the administration has been closely coordinating with representatives from MUIC to conduct further research into waste management strategies in the country.
She said the BMA has been steadily discouraging the use of styrofoam as a container for food, citing health risks related to its use.
However, she said it would be difficult for street vendors to immediately switch to biodegradable plates instead of using foam and plastic. She said the public must first take action to become more environmentally-concerned.
"If we ask vendors to switch from foam to tapioca-based containers, for instance, their costs would definitely increase, and they would not accept that burden," Ms Suwanna said.
"But if we start educating the public that eating from foam plates -- especially when the plates are put under heat -- will give them health problems, people will start to accept the extra cost."
BUI lecturer Madeleine Recknagel said Thailand is in dire need of a fully-functioning waste-management system, citing the 61 million foam containers are used in Thailand each day. "Everything that gets thrown into the canals eventually comes to the Chao Phraya River, where it gets washed out into the ocean," she said.
She said several plastic bottles in Thailand also still lack labels that classify the specific type of plastic used in the manufacturing process. "Each kind of plastic can be reused, so long as we know what type of plastic it is," she said. "Without this information, the BMA is unable to recycle the bottles efficiently."
Mrs Madeleine added that in her home country of Germany, retail stores levy extra charges on those who purchase plastic bottles. However, she noted those charges can be redeemed once the containers are returned to vending machines designated to collect used plastic bottles.