Environmental Engineering Reference
In-Depth Information
9.3.3
Tool: Integrated Phosphorus Cycle Input Output Table
9.3.3.1
Construction of the IPCIO
Based on the phosphorus flow data estimated so far, we established an Integrated
Phosphorus Cycle Input Output (IPCIO) database and its analytical model with the
following setups:
• IPCIO database with phosphorus contained goods flow.
• Phosphorus yield loss coefficient considering the difference between phosphorus
input as intermediate goods and output as produced commodities.
• Phosphorus recovery technology matrix as scenario parameters.
We defined phosphate ore, coal, iron ore, and limestone as R and yellow phosphorus,
dry phosphoric acid, and wet phosphoric acid as M. However, since many phospho-
rus-related commodities, such as phosphorus ore and phosphoric acid, do not exist
as independent sectors in the conventional input-output table, it is not possible to
examine the recycling of phosphorus through analyses employing the conventional
input-output table. For example, phosphorus ore is aggregated in the sector called
“other nonmetallic minerals,” which excludes items such as limestone and ceramic
mineral raw materials, and phosphorus compounds such as phosphoric acid and cal-
cium phosphate are aggregated in the sector called “other inorganic industrial prod-
ucts.” Therefore, while constructing the IPCIO model, the sector classification of
the conventional input-output table was revised to include items such as phosphorus
ore and phosphoric acid, which had been aggregated under the conventional sector,
as independent sectors. Furthermore, for waste material such as iron and steel slag
and sewage sludge, which are considered secondary resources of phosphorus, new
sectors were created, since they are not present in the sector classification of the
conventional input-output table.
While disaggregating and creating sectors, the method of classification differed
depending on whether the row or the column of the input-output table was consid-
ered. For example, since phosphorus ore can only be 'raw material' for phosphorus
products, it is not necessary to add 'phosphorus ore' as a sector in the column that
represents supply destinations. On the other hand, since phosphoric acid is the sup-
ply destination for phosphorus ore (wet and dry phosphoric acid are produced from
phosphorus ore) and raw material for various phosphorus products, it functions as
both a supply source and a destination, and a disaggregation of sectors in both the
row and column are required. By considering the above points, we extended the
conventional input-output table as in Table
9.2
and created an accounting matrix
that explicitly accounts for the flow of phosphorus-related commodities.
The allocation of the quantity of phosphorus required for each phosphorus-relat-
ed commodity to each of the supply destinations can be done in the following ways:
1. The value of the quantity of phosphorus supplied to each sector is determined on
the basis of the material flow estimated from industry statistics and data through
interview.
