Hammarby Sjöstad is a 250-hectare residential and mixed-use development on a former industrial site in the southeastern part of Stockholm, Sweden, which in the 1970s was the most polluted industrial port in the city's suburbs. In the early 1990s, in order to relieve the housing pressure in Stockholm and to bid for the right to host the Olympic Games in 2004, the Stockholm City Council planned the Hammarskjöld area as a future Olympic Village and began a series of comprehensive and sustainable urban developments.

Although the Olympic bid was ultimately unsuccessful, the ecological development of the Hammarskjöld area did not stop there, and the city building project team adjusted the master plan in time - creating an ecological concept community - and released the final version of the plan in 2002. We were fortunate to be involved in two technical energy saving projects for the community, water supply and drainage and waste recycling, from 2013-2015.

For water supply and drainage, the community built a separate water purification plant specifically to treat domestic drainage and recycle it back to residents' homes; green roofs and artificial precipitation canals to collect natural precipitation, and settled and filtered rainwater to be fed into Hammam Lake and the canal; and biogas extraction of sediment from the drainage system to use decaying bio-sediment for environmental fertilization.

In terms of waste recycling, a new waste recycling system has been established. Community environmental stations help residents sort their garbage, and garbage bins are connected to each other via underground pipes and transported directly to a central collection station by vacuum suction technology. At the central collection station, organic waste is transformed into bio-residue for fertilizer; hazardous waste is safely destroyed; and recyclable waste is recycled and reused as a new urban resource.

Encouraged by local government policies, the construction of Hammam Lake City takes sustainability as the core vision of the project, based on a complete overall strategic plan and teamwork design by professional project teams from multiple disciplines, to fully complete the construction in 2018 and become an industry benchmark with the successful construction on ecological sustainability.