Community sewage treatment system
Solution type: Combined greywater and faecal treatment system
- Objectives: Provide a sanitation solution in diffuse areas, which do not have sewerage networks, and at the same time use the treated effluent to irrigate crops that generate income for families.
- Description: The system combines greywater and faecal wastewater treatment with agricultural reuse, contributing to improved environmental quality and food security.
System operation
- Preliminary treatment: retention of grease by siphoning in grease traps – at least one per household – as well as the retention of sand by sedimentation and the retention of solids, both in a sand trap equipped with a grid.
- Secondary treatment: elimination of organic matter by microbial degradation in an anaerobic medium, inside the UASB reactor (upflow anaerobic reactor), equipped with phase separation structures to keep the solids inside the reactor, the expulsion of gases through a sigh and the evacuation of the liquid through a spillway followed by pipes to the polishing ponds.
- Tertiary treatment: elimination of pathogens (disinfection) by solar radiation under exposure for five to seven days. The system described here has the capacity to treat up to 10,000 litres per day, produced by about 100 people.
In addition to the specific dimensioning, the collection network differs for each situation. In addition to the structures already mentioned, which are responsible for the treatment itself, the system has auxiliary structures, such as: pass boxes for the convergence of the collection networks; inspection tanks; equalisation tanks; and reuse tanks.
Cost and resources
- USD 30.000 for 22 families
Advantages
- It allows community wastewater treatment, preventing the accumulation of stagnant water, responsible for (the proliferation of human or non-human diseases), soil contamination and bad odours, allowing the recycling of water and nutrients, and reducing environmental impact.
Sources:
- Summary information from the manual “Wastewater treatment systems and agricultural water reuse, a contribution to rural basic sanitation”, published by Victor Leonam, et al, 2023.