First, calculate the pounds of P 2 O 5 in the fertilizer: 2, lb fertilizer x 0. What is the cost per pound of P in the superphosphate from example B? Notice in example B that there were lb of P 2 O 5 in one ton of superphosphate. Converting P 2 O 5 to P allows for the cost per pound of P to be found.
Mixed fertilizers contain more than one nutrient. An example is granulated diammonium phosphate Although mixed fertilizers supply more than one nutrient, fertilizers should be mixed to meet the specific needs of the crop in question based on sound soil sampling and analysis. Example D. Calculate the cost of the P 2 O 5 in this fertilizer. What is the cost of the P 2 O 5 in using the value of N from urea see example A?
First, calculate the pounds of N and P 2 O 5 in a ton of fertilizer: 2, lb fertilizer x 0. The cost for P 2 O 5 can then be compared to other P 2 O 5 sources.
Notice that the cost of P 2 O 5 in was substantially less than the cost of P 2 O 5 in from example B. Example F. Care must be taken when approaching fertilizer value this way. Each element must be expressed on an elemental basis before its value can be calculated. What is the cost of total plant food in ? In one ton of , there are lb of elemental N 2, x 0. Table 3. When determining the cost per pound of nutrients in liquid-based fertilizers that are priced by the gallon, the density of the material must be known.
Process name. Cost data based on. Technical description. P recovery from the resulting sludge liquor by pH increase and Mg dosing, simultaneous precipitation of metals with Na 2 S. P recovery from the resulting sludge liquor by pH increase and Mg dosing, metal complexation with citric acid. Recovery of P as slag and metals in a metal phase.
Pilot with ash. Concentration of H 3 PO 4. Addition of dried sewage sludge as reducing agent to remove metals via off-gas and Na salts to improve plant availability. R1 Mono-incineration — Commercial operation Mono-incineration and landfill. Landfill of slag or ash. R3 Conventional recycling in agriculture — Commercial operation Valorization of digested sludge in agriculture.
MSWI, municipal solid waste incineration plant.. View Large. Depending on the input material used sludge, sludge liquor or sludge ash , the recovery processes intervene in different parts of the wastewater—sludge treatment—sludge disposal train.
Figure 1 shows the system evaluated for scenarios 1 to 5, which are based on sludge or sludge liquor. Figure 2 shows the system evaluated for scenarios 6 to 9, which are based on dry sludge or ash. Figure 1. View large Download slide. Figure 2. Sludge precipi-tation 1. Liquor precipi-tation 1. Liquor precipi-tation 2.
Sludge leaching 1. Sludge leaching 2. Metallurgic, integrated. Ash leaching 1. Ash leaching 2. Ash thermo-chem, integrated.
Less demand for polymers in dewatering. Sludge precipitation 1. Liquor precipitation 1. Liquor precipitation 2. Sludge metallurgic, int. Ash thermo-chem, int. Reference comparison.
Standard plant size Mio. Figure 3 compares how different recovery processes influence the cost of the wastewater and sludge treatment train, also showing the amount of phosphorus recovered.
The cost influence of phosphorus recovery is just as dependent on the existing sludge disposal route mono-incineration, co-incineration or use in agriculture as the choice of the recovery process. An even smaller amount of phosphorus is recovered by sludge leaching plants, which also have the highest specific costs per kg P. The precipitation plants recover only small amounts of phosphorus compared with the ash-based plants up to 36 times less , but their cost influence is low and sometimes they are even profitable.
Figure 3. The overall influence on wastewater and sludge treatment between processes is made up of cost types, which are shown per kg P recovered in Figure 4. The capex and the related maintenance cost are highest for Metallurgic sludge treatment and Ash leaching 1. Sludge precipitation and Liquor precipitation 1 also have high specific capex. The latter processes require several unit operations, and the specific capex and maintenance costs become substantial due to their low overall P yield.
Specific material costs are the highest for sludge leaching, which can be explained by the high acid consumption to dissolve phosphorus from a comparatively dilute matrix and subsequently the need for caustic to precipitate phosphorus again.
Sale of phosphoric material is counted only for Sludge precipitation 1 and Ash leaching 2, where a product price is guaranteed by the supplier. Operational benefits for the WWTP can compensate for other costs; the sludge precipitation process even becomes profitable overall. As mentioned, the processes based on dried sludge and ash scenarios 6 to 9 have an influence on the sludge disposal cost.
In Figure 4 the influence in a reference scenario with existing mono-incineration is shown. In this reference scenario, the cost for metallurgic treatment is partly compensated by savings, since incineration capacity is no longer needed. The ash-based processes also have slight savings compared with the reference as the landfill of the mono-incineration reference scenario is no longer needed. Existing mono-incineration is the most favourable reference scenario.
The cost influence of these processes on the co-incineration and agricultural use reference scenarios is higher Table 3. Figure 4. The sale of recovered phosphoric material could cover part of the recovery costs.
Liquor precipitation 1 and Ash leaching 2 already include revenue from phosphorus material sales in the specific net cost. Figure 5. Cost influence on the wastewater—sludge treatment train. Precipitation processes. Phosphorus recovery from municipal wastewater: an integrated comparative technological, environmental and economic assessment of P recovery technologies.
Search ADS. European Commission. Consultative Communication on the Sustainable Use of Phosphorus. Comparative Review of Ash Processes. European Commission no. Review of promising methods for phosphorus recovery and recycling from wastewater. These regions are dominated by highly weathered, phosphorus-poor soils that require substantial chemical amendment to increase crop productivity 8.
Many tropical soils are phosphorus-fixing, and added fertilizer phosphorus binds to iron and aluminium oxides, making it less available to crops 4 , 5 , 8 — Here we use farm-, state-, and national-level data from Brazil to understand how much inorganic phosphorus fertilizer, derived from finite resources of phosphate rock, has been needed to intensify agriculture on Brazil's phosphorus-fixing soils.
The phosphorus-fixing soil types that underlie cropland in Brazil represent three quarters of the phosphorus-fixing soils currently being used for crop production globally.
Thus data from Brazil can inform an estimate of the phosphorus consumption required globally if Brazilian-style intensification were to spread to phosphorus-fixing soils across the tropics.
Tilman, D. Global food demand and the sustainable intensification of agriculture. Natl Acad. USA , — Alexandratos, N. The revision. Google Scholar. Phalan, B. Reconciling food production and biodiversity conservation: land sharing and land sparing compared.
Science , — Sanchez, P. Fertility capability soil classification: a tool to help assess soil quality in the tropics. Geoderma , — Batjes, N. Global distribution of soil phosphorus retention potential. Bouwman, A. Human alteration of the global nitrogen and phosphorus soil balances for the period — Global Biogeochem. Article Google Scholar. Kuyper, T. Epilogue: global food security, rhetoric, and the sustainable intensification debate.
Palm, C. Soils: a contemporary perspective. Syers, J. Efficiency of soil and fertilizer phosphorus use: reconciling changing concepts of soil phosphorus behavior with agronomic information.
Riskin, S. The fate of phosphorus fertilizer in Amazon soya bean fields. B , Fritz, S. Mapping global cropland and field size. Change Biol. Goedert, W. Management of the Cerrado soils of Brazil: a review. The NSFP study was conducted statewide from to on irrigated corn sites over a range of soils and climatic conditions.
However, the Bray-P1 soil test values for phosphorus ranged from below 10 to over 80 ppm. Clearly there was no benefit to phosphorus fertilization at these soil test levels, as was the case when soil test phosphorus was above 25 ppm.
The price of DAP does not include delivery and dealer mark-up so in reality, future costs will be higher.
0コメント