Page 222 - Wastewater Solids Incineration Systems

188 Wastewater Solids Incineration Systems

process, which produces a soil that handles more easily, allows better drainage
and airflow, and includes some valuable minerals.
• Brick—ash has been used in brick manufacturing by various utilities quite
successfully. The brick manufacturers normally require large quantities of
ash at a time. Such quantities could be obtained from a lagoon that needs to
be emptied.

• Concrete fly ash—ash has been used as a fly ash substitute in concrete mixes.
• Asphalt additive—the ash has been used as a mineral filler and fine aggregate
in asphalt mixes.
• Others—one of the more innovative uses of incinerator ash is in vermiculture
process. The ash is blended with food waste material and worms are then
added. After an adequate period of time, the worms are separated from the
mixture, and the remaining material is used as a soil amendment.

Reuse options for incinerator ash tend to be site-specific. Utilities should pursue
all avenues available for recycling the ash. State departments of transportation
should be contacted to determine requirements for use of incinerator ash as a fly ash
substitute in concrete or as a mineral filler or fine aggregate substitute in asphalt
mixes. If the incinerator ash is approved for use in mix designs by the state depart-
ment of transportation, then a considerable market can be opened for reuse of incin-
erator ash. Table 8.1 contains the results of an ash survey conducted by the Northeast
Ohio Regional Sewer District (Dominak et al., 2005).

6.0 REGULATIONS

Regulations vary from state to state. In some states, ash is not regulated; in others, it
is treated as a waste product. Local, state, and federal regulations need to be checked
before disposal or reuse of incinerator ash. It is recommended that each facility do its
own research regarding local, state, and federal regulations with regard to ash dis-
posal and reuse.
Some landfills will require a toxicity characteristic leaching potential (TCLP) test
prior to accepting ash. The results of a TCLP test on MHF ash are shown in Table 8.2
(Hampton Roads Sanitation District, 2004). The pH of the ash is also a test that may
be required before landfilling.