BIOTEC has developed throughout the years a wastewater system with low investment costs (30 to 60 US$ per inhabitant). Likewise operation and maintenance costs are also very low (1 to 2 US$ per inhabitant per year). However the system only operates for wastewater temperatures above 15°C (all year long). This technology is typically “tropical region” orientated and its main applications are to be found in Latin America and India.
Treatment system consists in anaerobic reactors (UASB type), followed by (if required by local standards) trickling filters, SBR, submerged filters or stabilization ponds.
BIOTEC has been a pioneer of its like in Latin America developing UASB reactors for urban wastewater treatment under several climatic conditions (from high Andean plateau to Mediterranean areas). For more detailed information, please check the UASB publications.
Nowadays, BIOTEC UASB treatment plants are running in several countries such as Colombia, Venezuela, Nicaragua, El Salvador and Guatemala.
BIOTEC builds its plants in countries where the company is located. On the other hand it also give support to third parties or other companies (constructors, specialized water actors) so they can incorporate an UASB reactor in their own treatment plants. This leads to lower the sludge production as well as lower O&M costs.
A standard BIOTEC treatment plant is made of:
- Preliminary treatment (sieves, sand or oil removal equipments)
- UASB reactors with abatement levels of 80% of the COD and BOD
- As an option: trickling filters and secondary sedimentation tanks for removal of 50% of the remaining contamination (attain concentration of SS lower than 25ppm at the discharge point)
If an aerobic post treatment system is implemented downstream, the treatment plant delivers a transparent and odourless effluent. BOD levels being reduced down to 90% of their initial concentration. This exiting effluent usually holds more than 1 mg/L of dissolved oxygen. In addition this system is really compact requiring only 0,1m² per inhabitant.
In this kind of treatment system, sludge production is reduced to 0,5m³ per 1000m³ of wastewater. It is a fermented biological sludge easily dried out on simple “drying areas” (using solar radiation).
The system developed by BIOTEC is, as such, a “tropical revolution” due to its low investment costs. It makes urban wastewater treatment affordable for most of Latin America’s settlements.
BIOTEC has built plants for villages of only 440 houses to cities of 250.000 inhabitants.
BIOTEC vision also encompasses the use of the biological sludge generated in the treatment plant for agricultural purposes (organic fertilizer). Treated water can also be used as a crop enriching agent via ferti-irrigation systems.
The biogas generated can serve several purposes: electricity generation, cooking gas connections or using the gas for public lightening. Treatment plant sub-products used in agricultural activities can be seen as a direct benefit for neighboring stakeholders involved in the project. Moreover they enable the municipality (o the private operator) to generate additional incomes and developing local economy.
References
Colombia: El Vivero, Cali, Colombia, 45 L/s (20.000 inhabitant)
Guatemala: San Bartolo, Sololá, 22 L/s (10.000 inhabitant)
El Salvador: Ciudad Corinto, 14 L/s (7.800 inhabitant)
Nicaragua: Bosques de Capistrano, 4 L/s (2.000 inhabitant)
Venezuela: Punta Gorda, 6 L/s (3.000 inhabitant)
For more info see publications # 24, 26 & 29
