8 Things To Know About Recycling Water

By Yuanchao Xu 19 October, 2016

Recycling water could help alleviate some of China's water challenges. Check out 8 things to know about recycling

China’s water challenges are vast. The average annual water shortage of China is 50 billion m³. Even with the South-to-North-Water-Transfer project, water-recipient areas like Beijing and other cities in the Hai river basin will still have less water than international recognised water scarcity levels.
To reduce the country’s water challenges, China wants to comprehensively advance the construction of a water conservation society as shown in the 13^th Five Year Plan (13FYP). Water recycling and the use of unconventional water resources are highlighted in the plan.

China’s 13FYP highlights water recycling & the use of unconventional water resources

Unconventional water resources refer to reclaimed water from wastewater treatment plants, desalinated seawater and rainwater harvested in sponge cities. They provide another option for water consumers.
Here are 8 things you should know about recycling water in China:
 

1.    Various policies recently released on water recycling

Together with the 13FYP, a series of policies about water recycling have been issued recently (listed below).

2.    Over 80% of wastewater is treated but only 10% is recycled

Reclaimed water, which refers to the treatment and recycling of wastewater, is the most common unconventional water resource.

China’s total wastewater discharge increased from 61.7bn t to 71.6bn t from 2010 to 2014

China’s rapid urbanisation and industrialisation over the past few decades have led to large increases in wastewater discharge. China’s total wastewater discharge (mainly industrial and domestic wastewater) rose from 61.7 billion tonnes to 71.6 billion tonnes from 2010 to 2014.

The chart below (click on to enlarge) shows that between 2010 and 2014, domestic wastewater discharge increased (38 billion tonnes to 51 billion tonnes) while industrial wastewater discharge slightly decreased from 23.8 billion tonnes to 20.5 billion tonnes. The increase in domestic wastewater is probably caused by rapid urbanization.

Increasing wastewater discharge implies increasing water consumption, wastewater treatment demand, as well as the potential of reclaimed water use. The above right chart  shows that in urban areas, while the wastewater discharge increased, the amount of wastewater treated also increased. Actually, it did so at a faster pace. However, the amount of wastewater recycled and reused remains low at only around 10% of the wastewater treated. Great opportunities exist.

3.    Over 99% of cities in China are equipped with wastewater treatment plants

Currently, the use of reclaimed water is the main form of water recycling. And it depends largely on the wastewater treatment industry.

China began to focus its efforts towards wastewater treatment in 1998, with further efforts followed with the 11FYP and 12FYP, which facilitated the construction of wastewater treatment plants and drainage networks. By 2014, over 99% of cities in China had at least some wastewater treatment plants.

Despite the extensive coverage of treatment, excessive discharge, imperfect drainage networks and profitability concerns remain challenges for some local governments and managers of those plants.

4.    Challenges remain such as low quality reclaimed water, low profitability & more

Reclaimed water needs to fulfil certain requirements in order to be reused. Naturally, low quality reclaimed water hampers its use. An investigation by the Xinhua News Agency in 2014 showed that many treatment plants provide low quality reclaimed water. High retrofitting costs, inappropriate design of treatment plants and poor management may be to blame.

Water treatment fees paid are only about 1/3 of the actual cost

Low profitability is a significant problem. Researchers from Renmin University analysed data of 227 treatment plants. The results revealed that, depending on location, the average cost of treatment plants (operational cost and construction cost) is RMB2.73/m³. This is almost three times higher than the local average wastewater treatment fee paid to treatment plants, which is RMB0.76 (resident) and RMB0.98 (non-resident). This disparity between actual cost and fees received makes profitability very difficult.

5.   China’s seawater use & desalination capability have been increasing over the last 15+ years

The “Special Plan for Seawater Usage” issued in 2005, provided plans and guidance for seawater usage. It contains 10 key projects related to seawater usage, including seawater usage in cooling for different industries, domestic water use, drinking water and cleaning. It also stipulates that China will establish over 6 seawater use demonstration cities or islands for seawater usage by 2020.

There are two main ways of using seawater: direct use & use after desalination.

There are 2 main ways of using seawater: direct use & use after desalination

Direct seawater use usually refers to the use of seawater  in cooling applications of coastal power plants and petrochemical industries. As shown in our report Towards Water Risk Valuation, certain listed power companies generate up to 53% of their power using seawater cooling.

China initiated seawater desalination projects in the 1960s and has made substantial progress in recent years. According to the Seawater Usage Communique, from 2001 to 2015, China’s seawater desalination capability increased from less than 50,000 tonnes/day to 1,000,000 tonnes/day. A 1,000-tonnes/day seawater desalination plant on Yongxing Island was just put into use on 1 October 2016. Nowadays on Yongxing Island, desalinated seawater is able to fully satisfy the water use of its residents. In 2015, the top 3 desalinated seawater users were domestic water use (32.8%), thermal power plants (31%), and petrochemical industries (12.5%).

However, there are also many constraints. These include the relatively high desalination cost and associate energy consumption, the technology gap, incomplete seawater management, problems in including seawater in the water distribution scheme, and public understanding and acceptance of seawater desalination. Promisingly, the State Oceanic Administration (SOA) has started to search for solutions and collaborations for these.

6.    Sponge cities: a way to collect and reuse rainwater

Sponge cites are known to help with flood control though they can also contribute to rainwater reuse. The concept of sponge cities was raised in 2012, then emphasized by President Xi Jingping in the Central Government Conference on Urbanization in December 2013. For more see our article here.

Sponge cities store rainwater and reuse it through different methods. These include:

• Wet ponds – which are mainly used for landscaping purposes;
  
• Cisterns (a waterproof receptacle for holding liquids) and rainwater tanks – store rainwater for afforestation, road spray, flushing water; and
• Constructed wetlands (treatment systems that use natural processes involving wetland vegetation, soils, and their associated microbial assemblages to improve water quality)  – filters & purifies rainwater for further use.

7.    Water consuming industries are also recycling water

Water consuming industries including coal mining and power also recycle water.  Mine water collected from coal mines and coal washing water is usually recycled and reused. The government has standards and requirements for the water recycling rate for the mining industry. In the power sector, wastewater from cooling towers is reused for cleaning and spraying, and some ash water is reused in the cooling system. Some companies have their own wastewater treatment plants on site where wastewater can be treated and recycled directly within the company.

8.    Membrane bioreactor: a promising technology for water recycling

MBR (Membrane Bioreactor) technology is commonly used in water recycling like wastewater treatment and seawater desalination. It is becoming more popular and is increasingly promoted by policies. For instance, the ‘Notice on Accelerating the Development of Energy-saving and Environmental Protection Industry’

With MBRs water can pass through the membrane while pollutants can’t & are instead biologically treated

MBR is a combination of membrane and traditional biological approaches: water molecules can pass through the membrane while pollutants cannot and are treated by biological approaches. Advantage of MBR includes high quality of treated water, little sludge generation and little space occupation, but there is also high cost and high power consumption to consider.

The good news is that costs are reducing with innovations, as pointed out by Frost & Sullivan Environment (Water) Practice. Investment and operation cost (energy cost, labour cost and materials) for MBR will probably be reduced by about 15-20% in the next few years.

China’s water recycling industry is becoming more important as the country looks to grow whilst consuming less resources. However, despite promotion by the government and evironmental experts there are some general obstacles to address including technology, profitability and public awareness on the use of recycled water.

Further reading

• Unconventional Water For Power Generation – The power sector is China’s largest industrial water user & is also exposed to water stress. Unconventional water sources such as mine water & municipal wastewater can help with this. China Water Risk’s Thieriot explores these sources
• Sustainable Cities Water Index 2016: The Asian perspective – Now more than ever, cities & their waterscapes face challenges. Arcadis’ inaugural water index of 50 cities has 9 out of 12 Asian cities ranked in the bottom half. Arcadis’ John Batten expands on the results & more
• Paris Agreement: Food & Water Still At Risk – Even if all pledges made at COP21 are carried out, global staple crops face increased failures and 1.5 billion more people are to face water stress by 2050. Massachusetts Institute of Technology’s Mark Dwortzan shares more findings & solutions from their report
• Environmental Law: 1 Year On – China’s amended Environmental Protection Law has been in effect more than 18 months now. How impactful has it been? Have there been more fines & violations? What about compensation? China Water Risk sat down with Liu Feiqin, from the China University of Political Science & Law, to get her thoughts on this & more

• 8 Facts on China’s Wastewater – Don’t know anything about wastewater in China? Is it on the rise? Is industrial wastewater under-reported? Is it worse for rural areas? Check out our 8 facts from tech, key pollutants to standards
• Desalination: Proceed With Caution! – China is expanding capacity at a furious pace and by end of 2015 daily capacity is expected to be at 2.2mt/day up from 0.9mt/day in 2013, but Tommy Patterson from Kreab Gavin Anderson explains why investors should proceed with caution
• Sponge Cities: An Answer to Floods: Floods have cost China close to RMB2 trn between 2000-2014. Today, with 641 cities prone to flood risk, the Chinese govt has turned to sponge city pilots. Do they work? How much do they cost? CWR reviews
• Hong Kong Water: 5 Challenges: Industry veteran, Daniel Cheng, MD of Dunwell Enviro-Tech and Deputy Chairman of the Federation of Hong Kong Industries talks about HK’s 5 challenges in securing reliable water supply
• The War on Water Pollution – Premier Li has just declared war on pollution. Tan expands on the government’s stratagems & offensives and fundamental changes required to shore up the MEP’s arsenal in order to wage a successful war