Water Infrastructure for Sustainable Communities

A new model for water management is emerging worldwide in response to water shortages, polluted waterways, climate change, and loss of biodiversity. Cities and towns are questioning the ecological and financial sustainability of big-pipe water, stormwater, and sewer systems and are searching for “lighter footprint” more sustainable solutions. Pilot projects are being built that use, treat, store, and reuse water locally and that build distributed designs into restorative hydrology.

Content Table

Challenges and Visions for the Future Sustainable Cities and Villages

Cities and villages across the globe are confronting growing challenges of supplying safe clean water and sanitation services to residents and industry. Urban populations are expanding, climate change is beginning to create more erratic patterns of droughts and storms, and per capita consumption is on the rise. The water and wastewater profession is beginning to understand traditional linear infrastructure that transports clean water into and wastewater out of urban neighborhoods wastes water, uses too much energy, disrupts waterways and ecosystems, and is very expensive to build and maintain.

The Beijing conference was a follow-up of two international events that took place in the USA: (1) The Wingspread (Racine, WI) workshop, “Cities of the Future - Bringing Blue Water to Green Cities”  in July 2006 and (2) the Baltimore (Maryland) conference, “Water for All Life: A Decentralized Infrastructure for a Sustainable Future” in March 2007.

The Wingspread workshop and Baltimore conference forged a coalition of experts in urban water and drainage infrastructure, landscape, economy, environmental law, NGOs, sewerage utilities, academia, practice and foreign partners. At these two events a new (fifth) paradigm of ecocity urbanism was formulated, emerging from the past successes and failures of efforts to control pollution and reduce floods, offering adequate amounts of clean water for all beneficial uses, water and energy reclamation, and reduction of the carbon footprint. Next-generation designs come from a different engineering model: use, treat, store, and reuse water efficiently on a smaller scale, and blend these designs into restorative water hydrology. This paradigm of sustainable urban waters and watersheds is based on the premise that urban waters are the lifeline of cities and focus of the movement towards more sustainable and emerging “smart and green” cities. The concepts include reuse of highly treated effluents and urban stormwater for various purposes including landscape irrigation and aquifer replenishment; nutrients and energy recoveries from wastewater; environmental flow enhancement of effluent-dominated and flow-deprived streams; and ultimately a source for safe water supply. The new paradigm treats reclaimed water, nutrients and energy as a resource. Experts at both events proposed that this new paradigm of water/stormwater/wastewater infrastructure is based on decentralization and de-regionalization of the infrastructure systems and its management.

The new water management will make a switch from strictly engineered systems (sewers) to ecologic systems (rain gardens, surface wetlands, ponds, restored and daylighted water bodies) and ecosanitation. Municipal stormwater and sewage management is expected to be decentralized into city clusters rather than regionalized.  This book is another step forward in the development of a new paradigm for sustainably managing urban water in the future. Water management will shift in interlocking ways: water will not be used once and then thrown away, but rather treated and reused over and over; nutrients in wastewater will be captured and reused in fertilizer; biogas digesters will recover energy from wastewater and other solid waste and, in the near future, convert directly to hydrogen and electricity by fuel cells, rainwater will be captured for local use; green roofs and trees will capture stormwater, cool down buildings, improve air quality, and beautify cities; water will be returned to urban rivers and safe downstream uses; and the private sector will step forward to build and manage water in green buildings and integrated neighborhood infrastructure. The communities built or retrofitted according to the new paradigm will use less fossil fuel-based energy and emit far less green house gases. 

Objectives and General Outcome of the Conference

Specific objectives of the Beijing Conference were:

  • Update and expand upon the insights and lessons of the Wingspread Workshop and Baltimore Conference
  • Present case studies and identify lessons from sustainable water demonstration projects in China and other countries
  • Consider and make recommendations for how new water systems can be integrated into Chinese and other national policies and initiatives for urban and village development

With urban waters as a focal point, this conference explored the links between urban water quality and hydrology, landscape, and the broader concepts of green cities and smart growth. The conference focused on decentralized concepts of potable water/stormwater/ used water management that would provide clean water to multiple uses and result in sustainable water management systems.

The 2009 Beijing conference included leading experts who presented and summarized the ongoing efforts and movement towards the “Cities and Villages of the Future – the Ecocities” that are now emerging from the laboratories and design studios into  reality in some countries, including Australia, Belgium, Canada, China, Germany, Singapore, Sweden, United Kingdom and the US. The purpose of the Beijing Conference in 2009 was to further the learning process begun at the Wingspread Workshop and the Baltimore Conference and to advance the commitments made by signatories to the Baltimore Charter.

The subtitle of this book “China and the World” highlights the role of China and emphasizes collaboration between China and the United States and other countries. China is building new cities and new neighborhoods in older cities and has the opportunity to design sustainable infrastructure from the start.  The Chinese Ministry of Environmental Protection issued “Guidelines on building ecological provinces, ecological cities and ecological country” in May 2003 (revised in 2007). This has been followed by an upsurge in building sustainable cities. China is looking for urban housing for up to 300 million people in the next 30 years because of intensification of agriculture (loss of jobs of indigenous population) and a large increase of GNP being derived by industries in the cities. Essentially, it is a planned attempt to manage migration from rural to urban areas and to accommodate population growth that has been so devastating in several other fast developing countries, including Brazil, Mexico, India, etc.

The design of the area of Dongtan at the Yangtze River’s mouth to the sea near Shanghai included for the first time the ecocity concepts and outlined the difference between the now traditional Low Impacts Developments (LID) popular in the US and the concepts of water centric ecocities. In November 2007, governments of China and Singapore signed an agreement under which Singapore will export its ecocity know-how and technologies and will build an ecocity in Tianjin, 100 km southeast of Beijing. The University of California in Berkeley has teamed up with Siemens industry giant to provide know how to the Chinese planners in building the cities. Sweden is providing assistance to China on developing the new ecocity urbanism concepts in constructing a new site of the Capital Iron & Steel Co. at Caofeidian near Tangshan, 150 km east of Beijing. Now more and more Chinese cities from the north to the south are planning construction of ecocities, including Harbin, Shenyang, Beijing, Chengdu, cities cluster in the Pearl River Delta, etc. An ecological agriculture demonstration project has been almost completed near Xiaotangshan, 35 km north of Beijing, which combines the traditionally cultivating habits of Chinese farmers with ecological sanitation (Ecosan).

Other planned ecocities are emerging in Sweden, Canada (Victoria, Vancouver), Holland, Germany, Australia, and Japan. Components of the “Cities of the Future” have been implemented in Singapore, Masdar in Abu Dhabi (UAE) and Israel. Australia, South Africa and Israel have made tremendous advances in the field of water conservation. Singapore is a relatively small island city/state (4.5 million inhabitants, 626  km2) in South Asia that has minimal natural water resources. Until recently it imported most water for its potable needs from Malaysia. It is being converted into an ecocity that will derive much of its drinking water by collecting and reusing stormwater. Today, Singapore is a pioneer of water conservation, reclamation and reuse. These endeavours and many that will follow will create  more than a trillion dollar market throughout the world.

In the United States, urban water challenges are different. Water lines, sewer mains, and treatment plants, many built over a hundred years ago, are leaking, collapsing, and overflowing. Furthermore, they are incapable to handle extreme events that are expected to be magnified by global warming.  Because much of the water and wastewater infrastructure is well on its way to breaking, there is a golden opportunity to leapfrog into the future—as developing countries like China and India are beginning to do. Calling the US essential infrastructure failure an “opportunity” may seem counter-intuitive, but if these systems had been kept in good shape, there would actually be fewer openings to shift to something new. The worldwide economic potential of building new or retrofitting old cities to switch to the new paradigm of sustainable water/stormwater/wastewater management, to build the ecocities, is enormous and it is expected to reach several trillion dollars over the next 25 years.

European countries, Australia, and Canada have been ahead of the US in exploring radical shifts in water management. Since the Australian efforts in the early 1990s to implement water conservation, reclamation and reuse efforts based on the total hydrologic water cycle, the “green” city initiatives have been sprouting throughout the world. Notable examples already being realized include Hammarby Sjöstad, a waterfront district of Stockholm (Sweden) built on a former brownfield, where integrated  water/stormwater/wastewater management and reclamation as well as solid waste recycle, biogas and heat/cooling energy recovery and use of other renewable energy (e.g., solar) are implemented. In addition, Hammarby Sjöstad is a “green” city in many other aspects such as reliance on bicycles and public transportation, solar energy, use of ecotones as parks and buffers and others. Other notable developments are being realized in Malmő and Gőteborg (Sweden), in Holland, Denmark and Germany which are also leaders in the implementation of energy from renewable sources with zero GHG emissions.

The concept of “ecocity” cannot be limited to large urban areas. Many of the same concepts can also be applied to smaller communities. Rural ecovillages also need water conservation and reclamation, energy recovery from waste and manure, and provide protection to regional water resources and the ecology of the area. Family size solar energy heated water tanks or biogas production units are being implemented in China along with small household or community wastewater treatment and reclamation units. Effluent reuse for irrigation in small rural communities has been practiced for decades.   

Resources

This issues in this article are addresses in the book, Water Infrastructure for Sustainable Communities：China and the World, edited by Professor Xiaodi Hao, Professor Vladimir Novotn and Dr. Valerie I. Nelson .

This book compiles the presentations at the Conference on Sustainable Water Infrastructure for Villages and Cities of the Future (SWIF2009) held on Novemeber 8- 12, 2009 in Beijing, China.  Over 200 delegates from 15 countries attended the conference. 20 international scientists and experts were invited to present keynote lectures. Speakers from China included chief planners and university and national academy researchers working on the new ecocities, leaders in eco-sanitation, urban eco-development, energy and nutrient recovery, climate change impacts, and other emerging topics. After peer review, 50 peresentations were selected for inclusion into this book.

The book is divided into sections covering the following topics:

Sustainability of Urban Water Systems and Infrastructure; Water:Energy Nexus

This section covers the concepts of sustainable urban development, the driving forces for change, limitation of resources as impacted also by population increase and future outlook. It also focuses on the connection between water use, transport and treatment and its effect on the use of energy and GHG emissions. Some planned or already being built eco-cities and eco-villages are thriving for the net zero GHG emissions and promote water conservation, energy savings and production of energy from renewable sources.  Natural landscape and ecologic engineering are emphasized. Finally, in some developing countries that do not have safe infrastructure for providing potable water, a preliminary system of water distribution by public utilities has to be developed as a first step.

Precipitation, Stormwater Drainage and Hydrologic Cycle

Climate changes, rainwater harvesting, stormwater management using low impact development (LID) concepts in several Chinese communities, solids in storm sewers and innovative highway stormwater management are the topics covered in chapters of this section.

Used Water Source Separation and Decentralized Management

Considering used urban water, currently still called wastewater, as a resource may require decentralization and source water separation into black water (water containing mostly fecal matter), yellow water (urine) and gray water (cleaner but still polluted used water without black water and urine). Black water contains most of the organic matter while a small volume of urine flow (about 1 % of the total used water flow) contains most of nitrogen and about 50% of phosphorus. The chapters discuss the options for source separation, treatment technologies and reuse. 

Ecological/Small Community Sanitation

Hundreds of millions of people in China, Japan and other countries are still living in small communities. Therefore, it is natural that the book includes chapters on “ecosanitation” that is pertinent to smaller communities or urban clusters. Ecosanitation minimizes underground pipe infrastructure and eliminates the need for centralized western style treatment plants. It includes also a chapter on innovative small systems that treat and biodegrade organics based on natural principles and also on used water source separation. Examples and case studies of ecosanitation systems in China and Japan are presented in this section. 

Nutrient Management and Recovery

Nutrients (nitrogen and phosphorus) are pollutants causing excessive algal developments in receiving waters, especially in impounded bodies, including lakes and reservoirs providing potable water. Noxious algal blooms by green and blue green algae diminish beneficial uses of inland and coastal water bodies such as recreation and fishing and render impoundments unfit for water supply. The nutrient section of the book contains chapters on the concepts of nutrient recovery from used water, a case study on recovering phosphorus in the form of struvite, nitrogen removal by nitrification, and converting biomass to a mineral fertilizer struvite.

Treatment of Separated and Combined Used Water and Solids

The section includes a variety of chapters describing design of composting toilets, separate treatment of brown water, and nitrification processes in used water treatment and processes of particle separation. Topics also include measurements of endocrine disruptors, wetland construction with recycled materials and sludge treatment.

The book concludes with the future outlook and the current and planned programs by the International Water Association which is now in the forefront of the worldwide “Cities of the Future” efforts.    

In overall, this book provides a wealth of vision and implementation both for the international communities interested in Cities of the Future and specialists interested in the new development in China and other countries.   

References

Xiaodi Hao,Vladimir Novotny, Valerie Nelson, Sustainable Water Infrastructure for Villages and Cities of the Future: China and the World, IWA Publishing, 2010,  ISBN: 9781843393283

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