TM 5-814-8
sure that their facilities are designed, constructed,
(3) Secondary treatment. Secondary biological
managed, operated and maintained to conform
treatment will convert most of the soluble and
with Federal, State, interstate and local water
nonsettleable organic material into biological cell
quality standards and effluent limitations. These
mass. In the process, much of the organic nitro-
standards are or will be established in accordance
gen will be converted to ammonia. A small
with the Federal Water Pollution Control Act, as
fraction of the nitrogen, as well as a portion of
amended. All the U.S. EPA wastewater treatment
the phosphorus, will be tied up in the biological
requirements in furtherance of the Act have not
cell mass. The degree of bio-flocculation of the cell
yet been established. Treatment requirements for
mass will determine the efficiency of suspended
some industrial categories have been delayed due
solids removal in the final sedimentation step.
The activated sludge system achieves better bio-
to lack of developed technology; however, perti-
nent U.S. EPA regulations should be investigated
flocculation than the trickling filter process;
for specific details at a particular location. The
therefore, suspended solids in the final effluent
U.S. EPA has set effluent limitations for publicly-
from an activated sludge system are generally
lower than a trickling filter system.
owned and industrial wastewater treatment facili-
(4) Advanced treatment.
ties. Interpretation of these requirements as they
apply to military installations is as follows:
(a) Filtration. Filtration of a secondary ef-
fluent will reduce suspended solids considerably.
(a) Military installations which provide
wastewater treatment for principally domestic
The BOD is also lowered by the amount due to
sources will be required to meet criteria as set
the suspended solids in the secondary effluent.
forth for publicly-owned facilities.
Usually the soluble BOD in a secondary effluent
(b) Military installations which generate in-
is below 10 mg/L, so the majority of the BOD is
dustrial or process wastewaters will be required
exerted by the suspended organic material.
Again, trickling filter system effluents are not as
to meet either limitations set forth by that
well flocculated as activated sludge system ef-
specific industrial classification or limitations for-
fluents; therefore, multi-media filtered effluents
m u l a t e d by the U.S. EPA for that class of
from trickling filters will contain higher sus-
Federal facility.
pended solids than filtered effluents from an
b. System performance.
activated sludge system.
(1) Introduction. For the flow schemes pre-
(b) Vitrification. Little vitrification takes
sented in table 8-2, typical concentrations of
place in either the high rate trickling filter or
important wastewater constituents are given fol-
activated sludge process at normal design load-
lowing various stages of treatment. These concen-
ings. To assure good vitrification, a second stage
trations shall serve only as a general guide for
trickling filter system or suspended growth nitri-
preliminary planning purposes. It is emphasized
fication system should be employed. These sys-
that wastewater concentrations, both raw and
tems can reduce ammonia to about 2 to 4 mg/l,
treated at various stages, may vary widely from
a n d will also result in a reduction in the
those shown for a specific military installation. In
carbonaceous BOD.
many cases, bench or pilot studies will be neces-
(c) Phosphorus removal. Phosphorus re-
sary to predict the unit process loadings and
moval may be accomplished by mineral or lime
removal efficiencies that would be used in final
addition to the primary sedimentation tank, lime
design. The wastewater treatment alternatives
clarification of the secondary effluent, or addition
shown in table 8-2 include treatment processes
of lime or minerals to the final clarifier of
designed to convert or remove various forms of
trickling filter systems. Side benefits of these
the following constituents:
processes are suspended solids removal along
Carbonaceous BOD.
with removal of nitrogen and carbonaceous BOD
Suspended solids.
associated with the suspended solids. Mineral
Nitrogen.
addition to the primary sedimentation tank is the
least expensive process where phosphorus remov-
Phosphorus.
(2) Preliminary and primary treatment. Pri-
als of less than 90 percent are required. Bench or
mary sedimentation will remove a significant
pilot studies are necessary to determine the best
fraction of the suspended solids in the raw
chemicals to use as well as the required chemical
wastewater. It also removes the insoluble BOD,
dosage. Lime clarification of the secondary efflu-
nitrogen (primarily organic nitrogen), and phos-
ent is the process to use if high degrees of
phorus associated with the removed suspended
phosphorus removal are required. With low alka-
solids.
linity wastewaters, a two-stage lime clarification
8-3
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