Lightweight aggregate from flyash and sewage sludge

A method of treating flyash and sewage sludge for subsequent use, comprising the steps of:

• mixing flyash and sewage sludge in the proportions of about 35-99% dry weight flyash with about 1-65% dry weight sludge;
• agglomerating the mixture;
• drying the agglomerated mixture to a moisture content of less than about 5% by weight;
• heating the dried agglomerated mixture in a rotary kiln to form a nodular product;
• and
• cooling the product of the kiln.

A method of treating flyash and sewage sludge, comprising:

• mixing flyash with sewage sludge having a high fuel value;
• agglomerating the mixture;
• drying the agglomerated mixture;
• heating the agglomerated mixture to a temperature less than the melting point of the mixture in a rotary kiln using the agglomerated mixture as the principal source of fuel in the kiln to form a porous nodular product;
• and
• recovering the nodular product from the kiln.

A method of producing a lightweight aggregate, comprising the steps of:

• mixing flyash and sewage sludge in the proportions of about 35-99% dry weight flyash with about 1-65% dry weight sludge;
• pelletizing the resulting mixture;
• drying the pellets to a moisture content of less then about 5% by weight;
• passing the dried pellets through a rotary kiln co-current with the flow of hot gases to form a nodular product;
• and
• cooling the product of the kiln.