400 County Route 518 · P.O. Box 205 Tel: (609) 466-4900
Blawenburg, New Jersey 08504-0205 Fax: (609) 466-1231
Potential Emissions Rule Changes for Sewage
Sludge Incinerators, Multiple Hearth & Fluidized Bed
Revision No. 1 - Feb. 24, 1999
The "503 Rule" [40CFR Part 503] limits sewage sludge
incinerators to 100 ppm THC as propane, dry basis, corrected to 7% oxygen, averaged for 30
days. A well operated multiple hearth incinerator can meet this limit with the original,
1970's vintage equipment.
However, many states have more stringent emission limits. For example, in New Jersey, the
limit is 50 ppm, but as methane. On the surface this looks like half the federal limit.
However, methane has only one carbon atom compared to propane with three. Therefore, the
real ratio is about one sixth. But more stringent is New Jersey's limit of 100 ppm CO dry
basis, corrected to 7% oxygen. Once this low CO limit is met, the THC reading, in either
propane or methane, is virtually zero. Through a petition filed jointly by the sewage
sludge incinerator owners in New Jersey, the 503 Rule was changed to allow substitution of
100 ppm CO dry basis, corrected to 7% oxygen for the THC originally required. This allows
the use of a lower cost, easier to maintain CO monitor in place of the difficult to keep
online THC monitor. Unfortunately, the rule change did not allow for a more reasonable
level for CO emission. For the time being, if you do not have a low CO limit imposed by
your state codes, you are likely better off meeting only the present THC limit.
Initially, the EPA was considering promulgating new rules for sewage sludge incineration under Title I, Section 129 (solid waste combustion). This includes a MACT (Maximum Achievable Control Technologies) standard. In brief, this standard determines the performance of the top 12% of sewage sludge incinerators and that becomes the emission standard for existing installations. The EPA was not certain whether the 12% would be determined on an emission mass basis, a percent control efficiency basis, or some other basis.
The EPA may now be backing off from the demanding pollution
control requirements of Section 129. It is currently evaluating the
cost/benefit of dioxin and furan emission controls concerning sewage sludge incineration
and also the other pollutants listed under Section 129. As part of this evaluation,
the EPA is considering moving the impending rule changes form the all-source encompassing
regulations of CAAA, Section 129 to the more site specific Section 112 c6. Section
112 c6 does not include MACT compliance.
Of concern to existing sewage sludge incinerator owners is the cost to become compliant.
The top 12% of all have high temperature afterburners can easily meet a CO limit of 100
ppm. Afterburner selection, will determine the capital and annual operating costs, [see CBE article Afterburner Options]. Facilities
with fluidized bed sewage sludge incinerators will not require afterburners. About half of
the top 12% will have particulate or controls beyond the ubiquitous venturi-tray scrubber.
For example, a wet electrostatic precipitator or post cooler venturi scrubber.
For Information on Chavond-Barry Engineering and for continuing updates
in the EPA rule changes, visit our web site at http://www.Chavond-Barry.com
or contact Chavond-Barry Engineering Corp., Blawenburg, N.J.