[Adaptive optimized technologies for ecological sanitation and their complex ecological benefits].

Aiming at the ecological characters of the cities in central and west China, several ecological sanitary (ecosan) technologies with different adaptability were integrated, and five adaptive optimized technologies were established. The environmental effects, resources recyclable potential, economic benefits, management difficulties, and public acceptance of each of the technologies were studied, with the possible complex eco-benefits of the technical improvement assessed. The results showed that decentralized ecosan technologies had the advantages of conserving water, recycling nutrients and saving cost, but also had the problems in management and public acceptance. Centralized ecosan technologies had the advantages in management and public acceptance, but were short in high cost and low recycling potential. If the sanitary system was improved through applying ecosan technologies, the greenhouse gases emission (CO2 equivalent) and water pollution (calculated as BOD5) could be reduced by 70% and 30%, respectively, while recycled nutrients (the sum of N, P, K) could be increased by 15 times. The optimized system could supply 3% of domestic energy, 10% of domestic water, and 15% of food demand, and the total cost could be reduced by 56% when the resource-recycling benefits were taken into account.