Masks, protective suits, cotton swabs, and test kits used in normalized nucleic acid testing for COVID-19 under China's dynamic zero-COVID policy might create an increased environmental burden.

The press conference held on May 24 revealed that since March 1, Shanghai has collected, transported, and disposed of 68,500 tons of medical waste, which means that each Shanghai resident had produced more than 2 kilograms of medical waste, which is six times the usual amount (based on previous years). In the national annual report on solid waste pollution in large and medium cities released by the Ministry of Environment, in 2019, the total amount of medical waste in Shanghai was 55,700 tons, compared with 68,500 tons generated in only 3 months of 2022. In 2019, less than 10,000 tons of medical waste were generated in 1 month.

Since the beginning of the Covid-19 pandemic in 2020, medical waste has come under the spotlight of the environmental protection industry in China. Senior project manager of the Public Environment Research Center Dai Xiaojuan said: "During the pandemic, the medical waste wasn’t generated only by hospitals, fever clinics, centralized quarantines, and NAT points, but also by households - domestic waste is now a medical waste.”

Xiaojuan pointed out that the medical waste generated in Wuhan soared from 40 tons per day before the pandemic to more than 240 tons per day at the pandemic peak. According to a CCTV report, "Before January 16, there was only one medical waste treatment company in Wuhan, Han's Environmental Protection, which could only dispose of 50 tons per day even at full capacity."

Since then, urgent medical waste disposal facilities have been established in almost every hospital, central quarantines, and large-scale NAT points.

According to a report by Ping’An Securities, as of February 8, 2020, when the number of Covid-19 cases in China beat a record of 70,000, there were more than 17,000 tons of medical waste, most of it generated by hospitals and central quarantines. On the Chinese social media platform Weibo, nearby residents complained about the piles of medical waste, that allegedly was a source of infection for some residents of neighboring communities.

According to the data from Zhiyan Consulting, in 2016, the amount of medical waste generated in China was 2.146 million tons, and the treatment amount was only 747,000 tons. The treated medical waste accounted for less than 35% of the total.

So what is China's current medical waste treatment capacity? And what kind of challenges are posed to China’s fragile medical waste ecosystem by the normalization of the “72-hour” nucleic acid tests?

As a special kind of hazardous waste, medical waste ranks first on the "National Hazardous Waste List" as it’s considered a potential source of infection.

The "Regulations on the Management of Medical Waste" issued after SARS in 2003 stipulated that "the country promotes the centralized and harmless treatment of medical waste". This means that the collection and transportation of medical waste require closed-loop management to prevent the spread of diseases.

In March of this year, Li Yichang, deputy director of the Sichuan Provincial Department of Ecology and Environment, introduced at a press conference that to solve the problems of untimely collection of hazardous waste and unstable transfer, as well as the high disposal costs, the province has started the construction of 58 pilot projects for hazardous waste centralized collection.

A person in charge of a medical waste enterprise in Sichuan Province said that the collection and transportation of medical waste in more than 100 hospitals in the city is completed by 10 2-ton transfer vehicles. Most of them are transported to the county-level people's hospital for temporary storage. On the one hand, the original collection and transportation system was weak due to the inconvenience of grassroots transportation, long transportation distance, and a small amount of waste, but the more important reason was that the collection and transportation costs were not calculated separately.

Medical waste in various places is usually charged based on the number of beds/patient visits and the weight of waste. The China Business Industry Research Institute found that the charging standard is roughly between 2500-4000 yuan/ton. Taking Sichuan Province as an example, medical institutions above the “second-level” charge 2 yuan per day for the number of beds, and the medical institutions below the “second-level” charge 2 yuan per kilogram by weight. And since SARS, the increase in medical waste charges has been limited. International experience generally holds that the amount of medical waste generated in the inpatient department is 0.8kg/bed per day. Taking a hospital with 5,000 beds as an example, when the beds are full, 4 tons of medical waste will be generated every day, and a fee of 10,000 yuan will be paid. The disposal company only needs two transfer vehicles and four transfer personnel to complete the task. In some smaller urban areas, the same 2-ton transfer vehicle may need to run to 20 medical institutions to reach its full capacity. Taking into consideration fixed operating costs and medical waste disposal costs, the increase in shipping costs will naturally result in companies delaying the collection time as much as possible, changing from once a day to once every four or five days.

Sun Ning, Director of the Environmental Planning Institute of the Ministry of Ecology and Environment, put forward a suggestion on medical waste management in 2017. According to him, a separate qualification for medical waste collection and transportation should be implemented, as this would gradually reduce costs due to reasonable distribution among enterprises.

Incineration is an easily chosen technical path for the rapid treatment of medical waste. However, whether it is high-temperature incineration or post-disinfection residue incineration, the widely distributed chlorine in medical waste is the culprit of the high levels of dioxin - a highly toxic and persistent substance that is the unintentional by-product of medical waste incineration, with 6 times higher levels than in general hazardous waste.

The stable structure enables dioxins to exist in the environment for a long time, and accumulate and enlarge continuously through the biological chain.

At present, the emission standard of dioxins in the flue gas of medical waste incineration in China is 0.5ng I-TEQ/m^3. However, even if the emissions are all within the standard, the total amount has soared, and many environmentalists have called for attention to dioxin control.

In terms of the chlorine content required to produce dioxins, studies have shown that medical waste accounts for 4.56% to 7.52%, and other hazardous wastes account for 0.03% to 2.5%. This is closely related to the special use of medical waste. Chen Yang, a researcher at the School of Resources and Environment, University of Chinese Academy of Sciences, told “Eight Points Jianwen” that from the chlorine in medical sodium chloride solution to the chlorine in polyvinyl chloride organic macromolecules, these chlorine sources combined with macromolecules with benzene ring may cause the formation of dioxins in the process of pyrolysis and incineration.

Chen Yang said that the terminal control is carried out through the deep purification technology of exhaust gas such as activated carbon injection, deacidification and dust removal, and the process control of rapid heating, ensuring combustion efficiency and rapid cooling in the incinerator, including the source control of chlorine reduction from the source. The unification of all aspects is conducive to controlling the generation and emission of dioxins. But the reality is not so optimistic. The above-mentioned research results of Chen Jia show that only 43.90% of the dioxin emissions in the flue gas of 41 medical waste incineration and disposal facilities meet the standard. In 2017, Li Jiafu of Tianjin University analyzed 12 medical waste incinerators across the country and found that the toxic equivalent concentration of dioxins in the flue gas was 0.031-3.463 ng I-TEQ/m^3.

One of the challenges that dioxin poses to the researchers is that it can hardly be monitored in real-time like particulate matters such as PM2.5 and acidic compounds such as sulfur dioxide. Jiang Feng explained that since dioxins are trace pollutants, it often takes several days from sampling to pretreatment and analysis, and supervised monitoring is performed once or twice a year. In addition to dioxins, incineration will also produce highly toxic substances such as polycyclic aromatic hydrocarbons and polychlorinated biphenyls, acid gases such as sulfur dioxide, and nitrogen oxides, and heavy metals represented by mercury. Non-incineration disposal will produce odor, VOCs (volatile organic compounds), etc.

Sun Ning, director of the Environmental Planning Institute of the Ministry of Ecology and Environment, wrote in an article in 2017 that, compared with other hazardous wastes, the amount of medical waste is fewer, and it has not been the focus of environmental supervision by local environmental protection departments at all levels for a long time, and the country hasn’t implemented the discharge standards yet.

Shenzhen Zero Waste Environmental Protection Public Welfare Center collected the monitoring data of 56 companies from December 13, 2019, to March 13, 2020, and found that the average daily value exceeded the standard by 22.9%. During the period from February 13th to March 13th, 2020, the proportion of enterprises with excessive hourly average values ​​reached 25.7%, and the average level of enterprises with excessive hourly average values ​​was 53 hours.

Behind the frequent violations is the fact that medical waste disposal charges have not increased for many years. Sun Ning once pointed out that some enterprises with a strong sense of social responsibility can still be encouraged to maintain operation services, while some enterprises reduce technical requirements and emission requirements through various means and methods at the expense of the environment.

Chen Yang also said that activated carbon injection is beneficial for the adsorption of dioxins, but the adsorption capacity of activated carbon is limited, and it is affected by factors such as temperature and moisture, resulting in unsatisfactory treatment effects, and it is not easy to supervise. In the future, efforts need to be made in technological substitution and new technology innovations related to dioxin.

Medical waste treatment companies complain about the high operating costs and the slow increase in treatment costs. At the same time, medical waste production companies and hospitals are also complaining about treatment costs. The price has become a problem in medical waste production enterprises and treatment.

Since the outbreak of COVID-19, China’s Ministry of Ecology and Environment and relevant departments have issued several documents and related technical instruments to strengthen the capacity of medical waste disposal.

The disposal capacity and supervision level of medical waste have been actively enhanced. Looking forward, the Ministry will further strengthen the work of environmental supervision, targeting the waste caused by nucleic acid testing.