In Quebec, the municipalities must make sure that their rejections of sewer achieve the goals applied to the receiving medium. The Bio-fosseMC, developed by the biological processes division of H2O Innovation, showed its effectiveness during more than one year testing project, which contribute to the obtention of the standard Technology (CF-4) certification allowed by the Quebec Ministry of Environment (MENV) and the Department of Municipal Affairs (MAMM) http://www.menv.gouv.qc.ca/eau/eaux-usees/usees/biofosse.htm
Pilote Projet at Saint-Onésime d’Ixworth
The wastewater treatment station of the municipality of Saint-Onésime d’Ixworth (Quebec) was used as a pilot system for the Bio-fosseMD technology. After more than one year period of operation, the system showed its capacity to meet the requirements of the Quebec Ministry of Environment and the Department of Municipal Affairs, the whole activities being controlled by the Government Certified independent laboratory: Labexcel.
The wastewater organic treatment by Bio-fosseMD technology works according to a biological process treatment in aerobic medium. The process is done by the intermediary of a bacterial colony fixed on a submerged bacterial support and distinctive to the Bio-fosseMD: the aquatextile. The aquatextile used in Bio-fosseMD and Biotex, supports the biomass and contributes to reach high micro-organisms concentration in the aerobic zone. Oxygenation necessary to the microbial activity is provided by an air blower, which feeds the slopes of diffusers of fine air bubbles.
The treatment begins with a septic tank (individual or community according to the project). A two hours aerated equalization basin contributes to send a flow controlled to the Bio-fosseMD. A secondary settling tank, located at the exit of the Bio-fosseMD, allows the clarification of water treated and a recovery of biological muds produced. A aerated storage basin for biological muds completes the treatment. The supernatants of this basin come back to the head of the equalization basin.
Management of the Parameters
The output of the system was followed throughout all the demonstration. The principal parameters analyzed are:
- Biochemical oxygen demand (BOD5)
- Suspended solid (SS)
- Chemical demand for oxygen (COD)
The pilot period proceeded October 1998 to September 1999.
The medium flow during the pilot period was 46.7m³/j, that is lower than the flow design. During the test, observations allow to see that the quality of the supernatant of the muds basin was good. That contribute to note that the future installations must have a mud basin of a 250 day endurance. In addition, the unhookings textiles contributed to improve the fixing of the support of the Biotex.
The average concentrations obtained at the time of the test for the SS and BOD5 with the effluent are respectively 14 and 15 mg/L for the whole samples, that is an effectiveness of removal of 80 and 92%. The winter, the effectiveness was less (68% and 84%) with 20mg SS/L and 21mg BDO5/L. The summer, excellent results were obtained with 6 and 8 mg/L, that is 92% and 97% of removal, this being due to the temperature of the water which varied from 6 to 12 °C during the winter season and between 12 and 20°C during the estival season.
The objectives of rejections were respected. Following the obtantion of these results, the criteria of design were deduced and registered in the chart (CF-4) alloted by the MENV and the MAMM.
Sanction of technology
After analysis of the results, the Bio-fosseMD was classified 'standard' technology by the government of Quebec, what means that the performances of technology were followed by a committee of experts for at least a period of one year. At the end of the project, the committee recognized the effectiveness of the process.