How to integrate the informal recycling system into municipal solid waste management in developing countries: Based on a China’s case in Suzhou urban area

China and lots of other developing countries have been facing an increase in population and immense economic development that lead to an enormous growth in solid waste generation, and many developing countries aspire to achieve modern waste management systems. Domestic recyclable resources (DRR) are the recyclable part of the household waste, and are recycled mainly by informal systems in many developing countries. The recycling system in China is a typical example which exist in formal and informal recycling systems simultaneously. Based on filed research, questionnaire survey and interview, this paper carefully studies the recycling paths, material flows and cash flows in the informal recycling system in Suzhou urban area, and aims to give targeted policy suggestions in the framework of Pressure–State–Response (PSR) model. Based on the result, the recycling rate in Suzhou urban area was about 22% in 2013. It is suggested for the government to integrate the informal recycling system into municipal solid waste management by (1) giving professional training of the recycling practitioners and improving their recycling facilities, (2) giving the formal recycling channels a price advantage, (3) setting up information platforms, and (4) optimizing the layouts of recycling systems. These quantitate results and policy suggestions could be helpful to integrate the informal recycling system into municipal solid waste management of the formal recycling system