Sanitation and wastewater treatment scenarios and effects on global water quality and SDG 6

Based on a database with 200 countries, historical trends show an overall improvement of sanitation and wastewater treatment between 2000 and 2015. This improvement is, however, unequal between countries. Due to population growth, the number of persons without sanitation increased. Most countries without wastewater treatment in 2000 did not improve their wastewater treatment until 2015.

Future outlook showed an improvement of sanitation and wastewater treatment

A future outlook was based on the relationship between economic growth, population growth, and storylines of the scenarios. Future analysis for sanitation and wastewater treatment showed an increase in sewerage connection and wastewater treatment. The effects of sanitation and wastewater treatment were calculated as emissions of waterborne pathogens and nutrients. Local pathogen emissions decrease as a result of less unimproved sanitation, but downstream pathogen emissions rise with an increase of sewer systems. Nutrient emissions to surface water increase overall as a result of an increase of sewer systems without sufficient wastewater treatment.

SDG 6 will not be met by 2030

The Sustainable Development Goal (SDG) 6, clean water and sanitation, has two main targets: SDG 6.2, to achieve universal and equitable access to improved sanitation and to phase out unimproved sanitation, and SDG 6.3, to halve the proportion of untreated wastewater. Both SDG targets will not be met in 2030 but much later depending on the investments in sewer systems and wastewater treatment.