These are my notes, reworked a little, to capture the amazing information that came forward from a vendor at the Westside Innovation Days. Thursday April 30th.
Presenters: Chris Corps, Graeme Bethell, Laura Marcolini, Jack Gardner
Representing: Biowater Technology and Pivotal's Advanced Gasification
Laura is President of Biowater USA. And Jack is a wastewater advisor to Pivotal
Biowater is Norwegian based technology company that has offices in the US and manufactures their technology in Norway, US and Canada.
The presentation started with Pivotal explaining that their mission is to build waste management systems that recycle everything. For example, in the same way that Dockside Green recycles 100% of the treated water.
Pivotal presented a complete sewage treatment and sludge management system for the Region. The treatment process included:
Raw sewage being treated by Salsnes Filters as primary treatment which removes primary sludge, dewaters it and the water is then passed on to a secondary treatment process called Continuous Flow Intermediate Cleaning treatment (CFIC where nitrogen and organics are removed). The secondary treated sewage is then passed through ultra fine Ceramic Membranes (tertiary treatment) to remove all the solids and other contaminants such as drug resistant bacteria, microfibers and micro plastics, etc. The water from the membranes can be fully recycled and reused just like it is at Dockside Green. The secondary sludge is also passed through the Salsnes Filter and dewatered. Both the primary and secondary dewatered sludge is then processed and fed into a gasifier to produce heat and power. All of the components for this treatment system are modular in design and can be implemented just-in-time when needed.
The design for this treatment system was for the primary treatment to be based on 4x ADWF, and the secondary treatment to be based on 2x ADWF. Prior to primary treatment which removes about 50% of the solids from the sewage, grit and trash is removed by coarse screening. The first stage of CFIC removes nitrogen, the second and third stages remove organic material. This CFIC process is the next generation advancement of MBBR (Moving Bed Biofilm Reactor) technology. The tertiary membrane treatment operates similar to the hollow fibre membranes (Zee Weed brand). However there are some advantages including longer lasting and easier to clean, thus lower operating costs.
Very clean effluent that can be reused to flush toilets, irrigate landscaping and discharged to the inner harbour waters as is done by Dockside Green’s sewage treatment plant.
The sludge is then passed onto an Advanced Circle Draft gasification plant which is based on proven technology used in Austria and Italy.. The Advanced Circle Draft Gasifier has some features that make it more suitable for this application compared to Pivotal’s Fluidized Bed Gasifier. The Circle Draft is better suited to the volume of sludge produced, can be installed in modules and produces a cleaner syngas. There are three plants in operation in Europe and California and a new plant can easily be delivered inside of 12 months. The Advanced Gasification plants can be manufactured locally in Sidney BC.
In the proposal the total amount of daily sludge produced could be transported from the treatment plants to the gasifier in 7 trips per day for whole region.
The gasifier has no air emissions. It produces only syngas, heat and biochar and ash. When you use the syngas in a power generator the emissions are comparable to burning natural gas. Commercial plants have been in operation since 2002 in Gussing. In Cherasco Italy since 2007. In last few years five new plants have been built using this technology.
The Circle Draft gasifier has been tested using 50/50 mixtures of sludge and biomass in Cherasco Italy. Each gasifier has a small 3m (10 feet) square footprint and are very inexpensive compared to traditional sewage sludge treatment like anaerobic digesters.
One gasifier would suit a small community of 10,000 people based on the estimated amount of waste generated and due to the low cost of implementation while providing the benefits outlined for resource recovery.
The only moving part of the gasifier is the bucket conveyor to feed the system. Otherwise nothing moves. It operates at atmospheric pressure. The gasification temperature is 1000 degrees Celsius. This technology meets the BC Clean Energy Act so it can participate in the BC Hydro Standing Offer Program for clean renewable energy.
The concept presented can handle all the sludge for the CRD plus 60% of solid waste. Have tested and proven a lot of waste streams. Destroys drug resistant bacteria, micro plastics, etc.
The energy output based on 108 ML/d sewage volume and 29 tonne/day sludge volumes produces 120 M wHrs/day electricity and 190 M wHrs of heat, every day. The process also produces carbon biochar, that is almost pure carbon in nature, that has many uses in industrial filters. The process also produces 45 ML/year distilled water.
The presenters showed a case study listing with about 34 facilities. Many are retro-fit. Some are new. A 25 MLD sized facility needs a 25m x 50m footprint which was roughly the size of the presentation room where we heard the presentation. No need for 2km outfalls. It would not need to be sited on the waterfront. It can be better integrated throughout the region.
One of the outcomes from implementing similar renewable energy systems in Europe has been that they stimulate the local economy: through creation of many new local jobs, the green thermal energy attracts manufacturing and high tech, R&D, training and tourism! People want to see this technology.
The presentation showed that the annual revenues make this proposal $45M better than the CRD/Seaterra Plan for each year of operation.
Biowater/Pivotal can handle all the Westshore sewage flows in one site that is approximately the size of a city lot.
For the whole region Pivotal/Biowater capital costs are about $250M vs CRD Plan costing $782M. This $250M includes land acquisition, trucks, buildings, redundant systems, training, uniforms, etc, etc, etc,. A very detailed analysis.
The proposal uses the existing pipe infrastructure and includes costs for local connections to the new facilities.
In summary, it can be structured to be a profitable business rather than a drain on taxpayers. It can save taxpayers $ billions in operating costs and debt charges over the life of the facilities. The technology is proven and stable in several countries. New plants are coming on-line all the time. They are very small in size and can be put where you want them to maximize use of existing infrastructure and resource recovery. The systems would be future proof because it exceeds all the performance requirements and standards and can be easily expanded when needed.
The I&I in the region is significant problem. Esquimalt has done a lot to solve leaking sewer pipes. Because it uses less budget the region can reallocate money into fixing the pipes first and then you don't need to build a big plant. Pipes are a 100yr investment. This proposal does not need new pipes.
Question from audience: are there any odours in the bucket feed system? Answer: no because there is no moisture left in the sludge which has been pelletized and sterilized so very low odour.
Can the gasifiers be distributed throughout the community? The presenters suggest that the minimal cluster might be 3-4 gasifiers at one site. There would be a one or two processing centres but the gasifiers should be distributed. For siting the processing facility and gasifiers would need about 1.5 acre but distributed gasifiers could be located on a city residential lot.
Regards
Bryan Gilbert
Innovation Days:
Presentation slides:
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