Reuse of reclaimed water coming from a centralized treatment plant for domestic septic tanks wastewater
4 June, 2050
Waste water source
The wastewater treatment plant receives water with some sludge from individual septic tanks and from a small collective wastewater treatment installation.
Water input quality is :
- COD : 5 to 25 g/l
- Suspended Solids : 5 to 50 g/l
- NTK : 400 to 800 mg/l,
- Pt: 70 to 300mg/l
Distribution System
The reclaimed water is stored in a 140 m³ storage tank before primary treatment. Then water is distributed via a pressurized piping system that is around 2 km long to the plots. Irrigation is then performed using nozzles and micro-sprinklers delivering one feeding point for each tree.
Farming system
Forestry plantation (poplar and eucalyptus).
Waste water treatment description
Nutrient removal : Treatment on reeds beds with a total surface area of 2,600 m².
Pesticide removal : none
Disinfection : none
Suspended solids removal : Primary treatment with a central grooved disc filter.
Other :
Capacity
The system produces 6,300 m³ of reclaimed water each year.
Extent of the agricultural beneficiaries
The area irrigated with reclaimed water is about 3.2 ha.
Costs
The investments cost is 1.72 million euros, while the maintenance cost comes at 31,000 euros/year. The energy expenses add up to 14,000 euros.
Type of agreement
Not applicable as the fields belong to the community which is as well the owner of the WWTP. The fields supply firewood to the communal heat production plant.
Scientific results
Additional information
This project has several environmental benefits such as reducing sludge transport (100 to 120 km per day), avoiding direct discharge and reducing surface water withdrawals.
