What is BioElectro technology?
BioElectro is a patented process to treat biosolids with the application of a low-voltage gradient combined with a chemical additive that generates exothermic reactions leading to disinfection and stabilization. The process is characterized by a short detention time (less than 1 hour), while the controlled heat (up to 95ºC) stabilizes biosolids. The tests demonstrated log eight reduction of Clostridium perfringens’ spores in biosolids.
The process has the ability to convert existing anaerobic and aerobic digesters to production of Class A biosolids and to increase their existing capacity. The process can be applied in batch and continuous mode at a water resource recovery facility (WRRF) prior to or within existing digesters. A plug flow reactor in line with the existing waste activated sludge (WAS) facilities will allow the minimum reaction time, prior to discharge to an existing aerobic or anaerobic digester. Batch volumes will be varied to access changes in temperature with time and total retention time necessary to achieve full biosolids stabilization. The low voltage needed should require low electrical use. The limited detention time combined with a low chemical dose should limit chemical storage required and facilitate dosing utilizing off-the-shelf chemical metering equipment.
What are the benefits to implementing BioElectro technology?
- Provides a potentially economically viable conversion of aerobic digesters to Class A biosolids that have limited or no other conversion options
- Converts aerobic and anaerobic digesters to Class A biosolid production and increase their existing capacity
- Converting from Class B to Class A biosolids production allows greater flexibility in reuse of the biosolids, greatly reduces permitting and oversight requirements, and ultimately much lower management costs
- Production and reuse of Class A biosolids increases the sustainability of the WRRF operations
Who can benefit from the BioElectro process?
- Everybody who landfarms or landfills Class B biosolids produced from a municipal WRRF
- Everybody who currently aerobically or anaerobically digests their biosolids and has limited viable options to economically convert to Class A biosolid production
- Everybody who has capacity limitations with their existing digesters
- Everybody who is interested in promoting sustainability by creating Class A biosolids for reuse
Has the technology been tested, demonstrated, or implemented anywhere to date?
Technology development is at level one, since the BioElectro process has been successfully implemented at the bench scale. It has been tested at lab scale in one-dimensioned and two-dimensioned reactors. These bench tests have utilized both anaerobically digested sludge and WAS.
What are some of the next steps needed to advance the BioElectro technology?
The next steps are to provide pilot-scale and full-scale tests of the BioElectro technology. Piloting on a full-scale facility will be essential to confirm operational and cost requirements to convert existing digesters to achieve Class A biosolids production. The proposed steps are defined in three phases:
- Phase One (three-month period) – Bench scale refinements, where a series of tests in 1L-reactors will define an optimal technological parameter for phase two. The same sludge will be used in all three phases.
- Phase Two (three-month period) – Pilot scale test, where the system will be scaled up to a 40 liter plug flow reactor. The objective is to achieve no greater contact time than two hours and target disinfection and sludge stablization. Phases one and two will be performed at Concordia University, Montreal, QC.
- Phase Three (six-to-nine month period) – Full scale pilot tests, which will be conducted at an existing WRRF with existing digesters that do not obtain Class A biosolids production.
Upon completion of the full-scale pilot, an assessment of technical viability, operational requirements, and capital and operational costs will be provided.
How can LIFT help?
Since the LIFT program includes a group of municipal and industrial subscribers interested in the development and advancement of new technologies to benefit the wastewater treatment sector, the BioElectro process lies in the limits of LIFT’s interests. The intent of pursuing the LIFT program is to progress the technology through the technology development at level three, or applying the technology on a full-scale basis at multiple operational facilities if possible.
The team proposing on the process already has the commitment of chemical supply and facilities for phase one and two. Also, there are preliminary commitments for sites for implementation of phase three. For completion of phases one and two, the team is seeking a minimum of $115,000 of financial support to complete testing on the basis that the Canadian Government will provide matching funds of $115,000. Initial estimates to perform phase three at an existing facility are approximately $700,000. The $700,000 of support may be requested at the completion of phases one and two, with the benefit to any utility that implements the full-scale pilot to possess the installed equipment for use upon completion of the pilot. The refinement of the process during phases one and two, and associated cost and operational concerns should allow each utility to better assess if implementing phase three is a viable next step.