Geoscience Reference
In-Depth Information
A biosolids, Class B biosolids require land permits from the EPA for application.
There are several restrictions for use of this type of biosolids. It cannot be given
away in bags and cannot be sold. It is also prohibited to be used at sites that are open
to the public, lawns, and home gardens. However, it can be applied to mine recla-
mation sites, forests, and agricultural sites in bulk quantities if the biosolids meet
criteria for pollutants control, pathogen requirements, vector attraction reduction,
and other applicable requirements of Part 503 (NRC
2002
). Pathogenic microor-
ganisms have been found in Class B biosolids, including harmful coliform bacteria,
Esherichia coli
(
E. coli
), poliomyelitis viruses,
Shigella sonnei
, fecal streptococci,
and others (Lewis et al.
2002
; Brooks et al.
2005a
,
b
;Borjessonetal.
2009
).
Part 503 mandates isolation distances between the Class B applied agricultural
fields and houses, waterways and drinking water supplies (Table
10.2
) to reduce
potential exposure to humans and animals.
In Ohio, biosolids are applied through splash method or direct injection and can
vary in moisture content from 3% solids, a liquid or up to 40% solids, which is often
called cake. Splashing is the most common and least costly method for biosolids
application while the injection method is more costly. Injection is often used to
reduce VAR. Figure
10.1
shows an injection application of Class B biosolids in
Oregon, Ohio. In 2006, in Ohio, approximately 20% of biosolids (in dry tons) were
disposed of in landfills, 36% were incinerated while 46% were applied to agricul-
tural land - 35% was Class A biosolids while the remaining 65% was Class B
biosolids (OEPA
2006
).
Land application of biosolids is considered a beneficial use of the material.
Farmers use it because it is a free source of soil conditioner relative to providing
nutrients (i.e. fertilizer) and it improves soil structure. It is an innovative way to
recycle biosolids derived from municipal WWTPs. Land application supplies nec-
essary nutrients, including all of the phosphorous and part of the nitrogen needed
for crop growth. It also provides trace elements such as copper and zinc among
others. It is reported to increase agricultural productivity by improving soil struc-
ture, mainly due to increased stable organic matter (Eberle et al.
1994
). The stable
Table 10.2
Ohio EPA set isolation distances for surface and injection applications of Class B
biosolids
Isolation distances for surface
applications
Isolation distances for injection
applications
Land use type
Bedrock
3 ft
3 ft
Medical care facility
1000 ft
300 ft
Occupied buildings
300 ft
100 ft
Private potable
water source
300 ft
100 ft
Waters of the state
(excludes ground)
33 ft
33 ft
Sinkhole or UIC
class V drainage
300 ft without grass buffer, 100
ft with grass buffer
300 ft without grass buffer, 100
ft with a grass buffer
Source: Ohio EPA (
2002
)
