Phosphorus recovery and recycling - closing the loop.

There is a clear and pressing need to better manage our planet's resources. Phosphorus is a crucial element for life, but the natural phosphorus cycle has been perturbed to such an extent that humanity faces two dovetailing problems: the dwindling supply of phosphate rock as a resource, and the overabundance of phosphate in water systems leading to eutrophication. This Tutorial Review will explore the current routes to industrial phosphorus compounds, and innovative academic routes towards accessing these same products in a more sustainable manner.

Phosphate recycling in the phosphorus industry.

The feasibility of phosphate recycling in the white phosphorus production process is discussed. Several types of materials may be recycled, provided they are dry inorganic materials, low in iron, copper and zinc Sewage sludge ash may be used if no iron is used for phosphate precipitation in the treatment plant; using Ca or Al, or bio-P-removal, increases the recycling potential of the ash, but Cu and Zn are still present in problematic concentrations. Side stream P recovery as Ca- or Al-phosphates is a more attractive option and is discussed in detail.

Financial and administrative considerations.

The following is a discussion of some of the major achievements and problems in the implementation of PL 94-142 nationally. Existing and projected financial and administrative problems are raised, including a discussion of some of the confusion which has evolved in the provision of related services. The paper concludes with a presentation of decision-making guidelines regarding related services which may be useful to local educators in the IEP development process.