Piles of garbage may finally be disappearing from Phnom Penh streets after a strike by the city's trash collectors, but Phnom Penh is headed for disaster within five years unless it gets its waste management on track, according to an expert.

As workers for the city’s waste-management company Cintri returned to work on Wednesday after agreeing to wage increases, it emerged that the city’s Dangkor landfill, opened in 2009, could reach capacity in four to six years.

If it were to happen, the result could be crippling for an already drastically underfunded sector dogged by strikes.

A recent study by COMPED and a German engineering firm that analysed Dangkor’s capacity estimates that the cost of a new dump site would rise from $11.9 million this year to $35 million by 2022.

“Basically, there is about 1,500 tonnes a day going into landfill untreated,” said Jon Morales, program manager for the Asia Foundation’s Urban Services Program in Cambodia. “It is filling up very quickly and land is becoming more expensive, and [it’s] further out from the city, meaning driving there is more expensive.”

With the clock ticking, City Hall is searching for investors to help build an incineration plant to ease the pressure on the current site.

Phnom Penh Deputy Governor Aunny Ieng said the municipality had five interested companies, including firms from China, Thailand and Belgium, though he declined to name them.

“We are still looking and need to identity clearly the capacity and ability of investors who could do it,” Ieng said, adding that the future plant would also generate electricity and construction materials.

Phnom Penh Governor Pa Socheatvong also used a recent meeting with a delegation from China’s Tianjin province to appeal for investment in waste management and recycling in Cambodia.

Phnom Penh’s daily waste is set to increase nearly 50 per cent to 2,200 tonnes by 2020, and without a “profound change”, the city could be shelling out tens of millions of dollars every four to six years on new dumpsites, according to the report.

Funded by the Asia Foundation, the study found that using a compactor at the current landfill could extend its capacity to just over six years, while using a compactor and biologically treating the waste would push that to almost 12 years.

However, the report recommends a 15,000-square-metre $1.2 million composting plant, which it estimates will keep Dangkor operational for another 22 years.

Given that about 50 per cent of the city’s waste is organic, Morales said it could also be recycled into natural gas and methane.

He calculated the municipality’s current plan of incineration could extend the landfill’s lifespan by another four to five years, adding if nothing was done, the situation would become “a slow moving disaster”.