Mismanagement, faulty design blamed for landfill wall collapse

MANILA, Philippines - Experts and environmentalists yesterday accused the operator of the Rizal provincial sanitary landfill in Rodriguez town of “mismanagement,” as they said the collapse of its perimeter wall last July 29, at the height of typhoon “Kiko,” was not merely due to incessant heavy rains but rather the faulty design of the landfill.

Scientists and members of the Kalikasan-People’s Network for the Environment (Kalikasan-PNE) recently surveyed the landslide site and released an initial assessment yesterday showing the landfill’s faulty engineering design as the foremost cause of the perimeter wall’s collapse.

“Contrary to the explanation of the landfill operator, the steep slope and materials piled on the slope are major factors that caused the landslides and not just the heavy rains,” said geologist Catherine Abon, of the UP National Institute of Geological Science and the AGHAM group of activist-scientists.

The landslide debris, she said, comprised “unconsolidated soil and solid wastes, mainly plastic materials” that were dumped on a steep slope. 

“These materials caused the slope to be more unstable and vulnerable to erosion and landslide,” she added.

Landslide debris

Based on the initial findings, the landslide debris – a mixture of soil and garbage that flowed into the nearby water systems – was estimated to be around 110,000 cubic meters, equivalent to the hauling volume of 9,000 to 10,000 dump trucks.

Abon said the slope was estimated to be more than 50 degrees and had no retaining wall, thus could easily erode.

Clemente Bautista, national coordinator of Kalikasan-PNE, said that when the wall of the 19-hectare sanitary landfill collapsed, landslide debris blocked the Lukutan Munti Creek, creating an artificial dam. 

In effect, a high volume of water was impounded upstream, eventually leading to extensive flooding of some 2.5 to four meters high.

Bautista said the creek drains into Marikina River, which connects to Laguna Lake.

He raised alarm that the landslide has caused contamination in the area and posed serious repercussions on the health and environment of nearby communities.

“Based on the evidence we have, there (were) no sufficient and proper engineering technique and slope protection structures (in the facility) that (could) have prevented the landslide. In the absence of these structures and if another extreme rainfall occurs, there is a likelihood that another landslide could happen in the area,” Abon said.

‘Technically flawed’

Engineer Darrow Lucenario echoed Abon’s assessment, even asserting that the sanitary landfill “is technically flawed and dangerous.”

Lucenario, an environmental safety and sanitary expert, said that apart from the lack of safety engineering structures, the landfill has no leachate treatment facilities and disaster preventive pond that are needed to prevent, control and abate highly toxic garbage fluid, which could pollute surrounding water sources.

Lucenario surmised that another possible reason for the wall’s collapse could be an explosion triggered by massive methane gas buildup in the landfill.

“The Rizal provincial landfill does not have the proper landfill biogas collection and monitoring systems that could prevent an explosion underneath the mountain of garbage. Clearly, the operator of the landfill is violating safety standards and environmental laws,” Lucenario said.

“This is obviously mismanagement on the part of the landfill operator, the International Solid Waste and Integrated Management Specialist (ISWIMS). These amenities and structures should be present before the project approval and at the onset of the landfill operation,” Bautista said. 

“And in the absence of these facilities, the operator should have ceased and the environment department should not have allowed the dumping of garbage in the landfill,” he added.

Bautista said the owners of ISWIMS and the San Mateo Sanitary Landfill Development Corp. (SMSLDC), which is constructing a new landfill in San Mateo, Rizal, are the same.

The Department of Environment and Natural Resources’ Environmental Management Bureau (DENR-EMB), however, said the government could not just hastily order the closure of the Rizal provincial sanitary landfill for the obvious reason that Metro Manila’s garbage needs a dumping ground, otherwise wastes would pile up across the metropolis.

DENR-EMB director Julian Amador told The STAR that while one of the general findings in their investigation was that a large volume of water due to heavy rains caused the soil mixed with garbage to soften, it is nevertheless “indicative of poor structure.”

Notice of violation

However, instead of ordering the landfill to stop operating following the incident, Amador said the government issued a notice of violation against the operator last Aug. 13 and directed it to immediately come up with a rehabilitation plan that would include remedial measures to address the pollution of the river and prevent flash floods in the area.

The DENR-EMB also directed the operator to submit an emergency response plan, including a warning system for the possible occurrence of flood; an action plan to transfer the tipping area to “an appropriate and more stable location”; and the approved project design and actual design it has implemented.

A technical conference was set on Aug. 20 for the cleanup and rehabilitation of the Lukutan Munti Creek and the collapsed/completed cells, among others.