Two different proposals to start dealing with waste

Often the relationship between landfills and limitrophic land becomes unsustainable. The causes for the growing environmental, economic and social challenges and the possibility of transforming these challenges generated by the need to manage ever-growing quantities of waste have been previously described. The type of the power plant that is described integrates planning solutions of low environmental impact with the goals of treating and recovering municipal solid waste (MSW) from mixed collection. The scheme can be summarised in the following steps:

  • I. Refuse assignment
  • II. Mechanical biological treatment with the option of semi-automatic separation
  • III. RDF Preparation
  • IV. Metal cleaning, selling recycled material (glass, plastics, metals)
  • V. FBC, Fluidized Bed Combustor
  • VI. Steam or ORC Turbine with an electric generator
  • VII. Extraction of inert ashes for cementing / foundations for roads/buildings
  • VIII. Selling heat for heating/cooling In the following pictures we represent the process diagram:
waste01 waste02

Mixed waste is collected and disposed of, taken to the appropriate machines that have pincers and are subjected to their first assessment and laceration so as to open their bags and choose cumbersome materials. Next the waste is placed on a conveyor to undergo a semi-automatic biological and mechanical assessment.

The first stage of the assessment involves recovering ferrous materials through a system of magnets. Ferrous and non-ferrous materials are separated on the RDF lines and biodegradable organics are sent to the processing facility to be treated with scraps to eliminate varnish and other impurities from the recovered metals.

The type of processing plant is as per the Ki Energy patent described in paragraph 5.2 and is able to produce high-quality metals suitable for foundry. A semi-automatic assessment system completes the recovery procedure of recoverable and valuable materials. Residue material then undergoes a semi-manual assessment, to recover plastic and glass components. Raw material thus recovered is then prepared to be directed towards specialised recovery centres.

waste03

Waste that leaves this line is an RDF with a calorific value that can vary from 13,000 to 15,000 kJ/KG, depending on the type of MSW and the immediate surroundings. These traits allow for optimal use as a fuel for fluidised bed boilers along with a vapour turbine to produce electrical energy.

After this treatment the biodegradable fraction can be sent to the fluidised bed boiler to produce "clean" electrical energy. The treatment facility that Ki Energy proposes is based on well-established technologies that allow for operational continuity and ample flexible management.

Two different hypotesis that correspond to two different overall approaches will be briefly analysed:

  • Hypothesis A); involves mechanical biological treatment, with semi-automatic assessment of 500 tons / day of waste, thermal treatment ensues of all the fuel derived from the refuse, that has been expressly treated, in a fluidised bed combustor of 12MWe (i.e., treating and using all the refuse products in the fluidised bed combustor ).
  • Hypothesis B); involves mechanical biological treatment, with semi-automatic assessment, of 500 tons / day of waste, with thermal treatment of a quantity of fuel derived from the expressly treated refuse, enough to feed a processing plant of 5MWe in total, of which 2.5MWe for the fluidised bed combustor and 2.5MWe for motors and biogas (i.e.: treating all refuse products but only using a part in the fluidised bed combustor).

The main characteristics, in general terms, that correspond to the treatment facilities mentioned will now be further analysed.

Hypothesis A) - 12MWe PowerPlant

In the following table we present the general characteristics of a typical plant using Ki Energy technology for the refuses disposal. This hypothesis assumes the treatment of refuses for a total amount of 500 ton/day.

Type   Quantity   Unit
 
Refuses treated (1)   500   ton/day
 
Refuses treated (1)   180.000   ton/year
 
Refuses Recycled   14%   percent
 
Glass recycled   15   ton/day
 
Plastic recycled   45   ton/day
 
Metals recycled   10   ton/day
 
RDF for FBC   400   ton/day
 
Total Thermal Energy (2)   46   MWt
 
Electric Energy provided (3)   12   MWe
 
Thermal Energy for cooling   12   MWe
Evaluation based on MSW standard data
(1) Refuses produced by 300000 inhabitants.
(2) Able to cool 5.500 flats.
(3) Able to provide electricity for 6.000 end-user.

The estimed cost for the 12MWe plant its about 40 Milions Euro. A further accurate estimation involves completing specific preliminary investigation, region examination, and feasibility study led by Ki Energy's experts.

Hypothesis B) - 5MWe Power Plant

This second hypothesis assume the biological/mechanical treatment of refuses for an amount of 500 ton/day and the thermal treatment of RDF for a total amount able to feed a 5MWe plant.

Type   Quantity   Unit
 
Refuses treated (1)   500   ton/day
 
Refuses treated (1)   180.000   ton/year
 
Refuses Recycled   14%   percent
 
Glass recycled   15   ton/day
 
Plastic recycled   45   ton/day
 
Metals recycled   10   ton/day
 
RDF for FBC   167   ton/day
 
Total Thermal Energy (2)   19,2   MWt
 
Electric Energy provided (3)   5   MWe
 
Thermal Energy for cooling   12,7   MWe
Evaluation based on MSW standard data
(1) Refuses produced by 300000 inhabitants.
(2) Able to cool 2.300 flats.
(3) Able to provide electricity for 2.500 end-user.

The Ki Energy power plant, optimised due to the production of a total of 5Mwe, uses the integrated use of a 2.5MWe fluidised bed combustor, driven by suitably treated waste products, as well as gas motors for a total of 2.5MWe, driven by landfill biogas. The estimated cost of the plant is around €23 million. A more accurate estimate involves completing specific preliminary investigations, region examination, and feasibility study led by Ki Energy's experts.

Hypotheses A) and B): labour, market and opportunity

In both hypotheses it is possible to stipulate the major occupational effects due to both the direct increase in the demand for workforce and the creation of labour.

To cover all bases, direct occupation produced by the typical Ki Energy power plant equivalent to 5MWe is indicated.

Number   Role   Responsability
 
1   CEO   Whole Plant
 
2   CEO Assistant   Production Area
 
2-3   Electric, Electronic Engineer   Technology
 
3-5   Machine Operators   Elevators, vehicols, hammer grab
 
2-3   Lab personnel   Production control
 
30-35   Screeners   Refuses screening
 
2-3   Administration    
 
30%   Replacement    

Based on market statistics (source: Greenpeace, year 2005) an estimate of market prices for useful raw materials recovered during mechanical biological treatment is provided.

Type   Price   Unit
 
Glass   25   €/ton
 
Plastic   51   €/ton
 
Ferrous Metals   32   €/ton
 
Non Ferrous Metals   500   €/ton

Economic Hypothesis

The IRR from the investment for this kind of project can varies depending on the case that should be studied, but exceeds 30% in most of the situations.