劉莎

Chinas deadly construction waste woes

深圳滑坡事故是一場人禍，發(fā)展余泥渣土回收利用技術或許可以避免悲劇再次發(fā)生

Everything He Weiming knew disappeared on December 20， 2015， when a landslide hit the Guangming New District of Shenzhen. His parents， sister， wife， and son took their last breaths under a thick pile of red mud.

The landslide destroyed 33 buildings in the Guangming New District and claimed at least 58 lives. He Weimings family， who had migrated from Henan Province， was running a small industrial waste company. On December 20 they were preparing for a Spring Festival reunion and had invited their relatives in Henan to join them.

But the tragedy meant that only he， his younger brother， and his mother-in-law attended， with grief as an unwelcome guest. As of February they were still waiting for compensation that had yet to be confirmed by the government.

These kinds of landslides can， unfortunately， be a problem throughout China， as rapid construction means there simply arent enough places to store gargantuan quantities of dirt.

In Hes case， the landslide occurred around 11： 30 am and He was not at home that morning. On his way back home around noon ， he was shocked to see nothing but red mud covering the buildings he passed by every day.

Liu Qingsheng， the vice mayor of Shenzhen， said the landslide covered 380，000 square meters， about the area of 60 football fields. AFP quoted another official as saying the mud was up to ten meters thick.

Beijing soon sent a group of officials and geological experts to the southern city and the investigation results indicated that this was a work safety incident rather than a geological disaster. What collapsed was not mountain soil or rock， but a huge pile of construction waste， mostly dirt， which had grown into a 100-meter- high hill over the last two years.

He recalled that， in the past two years， his truck full of industrial waste would often encounter larger trucks of soil heading to the dirt hill.

The investigation results helped many people to understand why a landslide， which can often happen in rainy seasons and mountainous areas， could happen to an ordinary， relatively flat city like Shenzhen.

The fast-growing and populated city， with an estimated 20 million people， has been troubled by excessive amounts of dirt and debris generated during construction and a severe lack of dumpsites to store the dirt.

The deadly debris hill grew out from a dumpsite near the Hengtaiyu industrial park in the Guangming New District. The dumpsite， located on top of a disused quarry， was put into operation in 2013. The site operator submitted an environmental impact report to the local district government， saying it was necessary to operate a dumpsite because the district was developing so fast—with many new developments being built and loads of debris and waste being generated.

This is true not only for the district but the whole city. In the following two years， the demand for dumpsites grew fiercely with subway line expansions. In 2014 alone， the volume of construction debris and dirt in Shenzhen was 30 million cubic meters. But in 2015， there were only 12 construction dumpsites in Shenzhen and the collapsed one was among them. And as the Shenzhen Special Zone Daily reported， five of them were saturated in 2013.

The existing dumpsites are overwhelmed， but theres also the fact that excavated soil and dirt are dumped randomly in suburban areas and illegal dumpsites that charge lower prices than legal ones， damaging the environment and creating extremely dangerous dirt piles untouched by regulation.

Experts from the Ministry of Land Resources pointed out that such accumulation was loose and steep—prime territory for a collapse. Unlike a rockslide or natural mudslide which show signs of danger， such as during heavy rainstorms， such piles of soil are notoriously difficult to predict. They could collapse at any time.

Its obviously a problem for other cities in China. In 2014， Beijing generated over 40 million cubic meters of dirt and according to a rough calculation by the Beijing News， Hangzhou， capital of Zhejiang Province， accumulated enough construction dirt to fill up West Lake， Hangzhous most famous scenic spot， three times over. It was an impressive quantity given the fact that West Lake is 6.39 square kilometers and has an average depth of 1.97 meters.

All over China， more than 1.5 billion tons of construction waste were generated in 2014， accounting for 40 percent of total waste， and with the rapid urbanization process and more second-tier cities developing subway lines， the number will continue to rise and reach a peak in 2020， according to a report by the China Strategic Alliance of Technological Innovation for the Construction Waste Recycling Industry.

Influenced by the Shenzhen incident， the Guangdong provincial government launched a campaign to regulate excess soil dumping.

Over 100 cities have their own regulations on dumping construction waste and excess soil， but most of the punishments are just warnings and fines. Since a lot of the construction waste is dumped in suburban areas， it is difficult to trace them.

In Jinan， capital of Shandong Province， over 53 million cubic meters of excavated dirt have not been dealt with， and it is scattered over 1，000 different locations， the Jinan News reported last December. Local police caught truck drivers who were transporting soil at night but could only punish them for overloading.

Chinese cities have not yet developed recycling techniques to turn this soil into a resource. In Zhengzhou， capital of Henan Province， for example， a China National Radio reporter discovered that plenty of excess soil was simply dumped beside the road and construction workers lived nearby.

Only five percent of construction waste is utilized in China， while in Japan， Germany， and the US， the utilization rate stands at 90 percent， says Xing Feng， a professor with the College of Civil Engineering at Shenzhen University.

An official with the Jinan Urban Management Bureau concluded that there are basically three ways dirt and soil are dealt with during construction： one third goes to legal dumpsites， one third goes toward a recycling process to be used as construction material， and the remaining third is dumped near the construction sites， the South China Morning Post reported.

Landfills are also an option. Shenzhen used to transport the soil in Baoan and Nanshan districts to land reclamation sites in Zhuhai， a city constantly in need of soil for shoreline expansion projects.

Pan Weibin， professor with School of Environment and Energy at South China University of Technology in Guangzhou， suggests that the government should ask construction companies to record the volume of construction waste and have them report how they deal with the waste.

This is the method currently used to regulate hazardous waste and it could also be applied to tracking construction soil to regulate construction companies， Pan told theYangcheng Evening News.

In July 2015， four kilns in the Jiangning District of Nanjing， capital of Jiangsu Province， started to receive excavated soil to turn into hollow bricks. This is the first time Nanjing has attempted to recycle construction soil. Admittedly， these bricks arent that hard and cant be used as construction material， but it is an effective way to deal with a growing problem—one that will improve with time and technology.