B2 - Build COWS prototype subsystem
B2 - Build COWS prototype subsystem Tendering and contracting for COWS prototype M - Contracts awarded Assembly of COWS prototype subsystem Stand alone test Successful test of stand alone function D4 - Prototype test of reference and acceptance report
Contents
Alert notice[edit]
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{{#if: |}} Note: {{#if: |{{{1}}}Description and methods employed (what, how, where and when)[edit]
What[edit]
Construction of the prototype subsystem for pre-treatment is fundamental for the success of the plant and the demonstration. The strategy of extracting the maximum useful organic content for anaerobic digestion is well consolidated. Also, that of enriching sewage sludge with OFMSW has by now passed all the tests of effectiveness. But the most widespread solutions are based on different application hypotheses from that of COWS, which alter the decisional parameters. In most cases the techniques available on the market start from the idea of building a new installation, generally near a dump.
However:
- this is not the case for Viareggio and for SEARIS and SEAAMB which are proposing COWS; nor is it the case of the observers who have already expressed their interest in the project, such as AAMPS and ASA of Livorno;
- the number of existing sludge treatment plants that can be converted to the COWS process is not even comparable with the number of new plants planned for construction.
How/Methods[edit]
COWS focuses on the efficient reconversion of existing sewage sludge treatment plants.
In the co-digestion of sewage sludge and OFMSW
- the pre-treatment of separation serves to reduce the presence of non-biodegradable materials and contaminants (glass, ceramic, plastic, etc.) or unsuitable materials;
- disintegration serves to improve the contribution to co-digestion (for better participation in the fermenting processes and better mixing with the sludge).
In the preliminary analyses and during the operation of the small experimental plant from 2005 to 2007, SEARIS and SEAAMB were able to compare the technologies available, which – with some simplification – can be grouped under three headings:
- technologies concentrating on the selection of raw materials for grinding and then pulping;
- technologies that grind the materials and separate them during the pulping state (usually using hydro-mechanical pulping units);
- separation done by pressing OFMSW (piston feeding or screw): exerting high pressure in a perforated extrusion chamber results in a fluidization of organic parts expelled from the chamber. Materials remaining inside the chamber are mechanically more resistant and possibly contrary to fermentation.
Since the end of the experimentation in 2007, the COWS partners have continued to observe, with care, the evolution of the performance of these technologies and, for the COWS prototype, they find that the pressure/extrusion separation method is potentially the most promising. They also believe that it is necessary to work toward developing a prototype with good performance based on a project that is relatively generalizable, rather than on individual performances. (E.g. the effectiveness in the disintegration of the OFMSW is not in itself a guarantee of the absence of contaminants. See William F. Brinton, Jr. Characterization of Man-made Foreign Matter And its Presence in Multiple Size Fractions From Mixed Waste Composting. Compost Science & Utilization, (2005), Vol. 13, No. 4, 274-280).
The choice will therefore be made on the basis of the results of the screening performed in action A1 and on the basis of the responses to the invitations to express interest (also in action A1).
The COWS partners are interested in the performance of the machines offered by the vendors, and in their willingness to alter and adapt them to the COWS logic. In most cases, the technologies come from other sectors (paper pulp, plastic extrusion) and, as we have said, have been adapted for use with co-digestion systems to be built from scratch, while here we are talking about modifying, adjusting and balancing a solution that is functional and responds well to a reasonably high variability of input materials.
This action will involve:
- examination of the expressions of interest and interviews with the vendors, if possible also with a vendor panel in which the companies offering the technologies present their solutions in a comparative manner;
- revision of the final terms of reference, on the basis of the project developed during action A1;
- tendering and evaluation of bidders proposals;
- contracting and operational planning;
- construction of the prototype unit;
- assembly and installation;
- off-line stand-alone test and provisional acceptance
- plug into the external system
Where[edit]
This action will mainly take place at plant site in Viareggio, Tuscany (IT) (some visits will be made to vendor facilities).
When[edit]
06/09/2013 - 30/10/2014
Integration of prototype substation into the overall process will be done within Action B1 (starting on 31/10/2014, ending in January 2015)
Constraints and assumptions[edit]
- Constraints
- Execution must be completed on schedule in order to leave significant time to demonstration of running process.
- Assumptions
- Equipment supply and installation does not face unforeseen, blocking issues
- No disrupting organizational change will occur in suppliers organizations
- Turnover of key project resources is low.
- Delays on critical path may be handled by careful monitoring and control by project management. Buffer time allocated in planning is sufficient.
Beneficiary responsible for implementation[edit]
P1 - SEARIS
Expected results[edit]
The principal result of this action is
- COWS prototype OFMSW pre-treatment is installed, tested and ready for test-run on Action B3
- relevant documentation D4 - Prototype terms of reference (specifications) and acceptance report are available
Indicators of progress[edit]
- Schedule and effort variance;
- actual vs. planned start/duration of tasks (if buffer time reserved for contingency is to be used then remediation actions must be triggered);
- actual vs. planned resource use (15% work overload and 5% budget variance are thresholds for triggering remediation actions)
- Performance
- Delivery of compliant outputs:
- tender terms of reference and documents for COWS prototype, contract documents
- Quality of delivered outputs: acceptance test documents for COWS (off-line, standalone tests)
