ANAEROBIC TREATMENT PROCESS - Institut Teknologi ?· ANAEROBIC TREATMENT PROCESS Marisa Handajani. Anaerobic…
Post on 10-Mar-2019
Embed Size (px)
Methane fermentation is a versatile biotechnology capable of converting almost all types of polymeric materials to methane and carbon dioxide under anaerobic conditions.
Tahapan Proses:1. Hidrolisis
3. Metanogenesis3. Metanogenesis
Microorganisms : 1. fermentative microbes (acidogens);
3. acetate-forming microbes (acetogens); and
4. methane-producing microbes (methanogens) harmoniously grow and produce reduced end-products.
Anaerobes play important roles in establishing a stable environment at various stages of methane fermentation.
Reaksi pembentukan Metan:
Anaerobic Wastewater Treatment:
Anaerobic wastewater treatment is the biological treatment of wastewater without the use of air or elemental oxygen. Many applications are directed towards the removal of organic pollution in wastewater, slurries and sludges. The organic pollutants are converted by anaerobic microorganisms to a gas containing methane and carbon dioxide, known as "biogas" (see Figure 1 below). below).
Figure 1. Conversion of Organic Pollutants to Biogas by Anaerobic Microorganisms
COD Balance:In the wastewater engineering field organic pollution is measured by the weight of
oxygen it takes to oxidize it chemically. This weight of oxygen is referred to as the
"chemical oxygen demand" (COD). COD is basically a measure of organic matter
content or concentration. The best way to appreciate anaerobic wastewater treatment
is to compare its COD balance with that of aerobic wastewater treatment.
Anaerobic vs Aerobic Treatment for 1000 kg CODB/d
Parameter Anaerobic Aerobic
Power consumption (kW) 1.5 65
Net biosolids prod. (kg TS/d) 15-100 200-600
Energy produced (kW) 140 Nil
Less nutrients required;
System can be shut down
for extended periods
Anaerobic treatment cannot
achieve surface water
discharge quality without
post-treatment; without serious
Can handle organic shock
Reduced sulfur compounds
are produced, which need
to be properly addressed in
terms of corrosion, odor
and safety; and
Longer start-up period.
systems where the bacteria grow and are suspended
in the reactor liquid 'granular' or 'flocculent
utilize either fixed film or carrier media (which is
suspended in the liquid) for the bacteria to grow on
and attach to.
Application "High Rate"Anaerobic Treatment:
Granular sludges exhibit high settling velocities and activity rates reduce reactor volume
and increase the organic loading rate depend on wastewater characteristics, system
configuration and loading condition
granular sludge is retained in the system by specially designed gas-liquid-solids separation granular sludge is retained in the system by specially designed gas-liquid-solids separation
Low Rate"Anaerobic Treatment:
SRT = HRT
effective when treating wastewaters that do not granulate well or have substances that
effect the retention of granules at high loading rates (i.e., high concentrations of fat, oil or
grease (FOG), total suspended solids (TSS), COD, salts, total dissolved solids, calcium, etc., in
The net effect is that slow growing anaerobes can be
maintained in the reactor at high concentrations, enabling
high volumetric conversion rates, while the wastewater
rapidly passes through the reactor.
The main mechanism of retaining sludge in the reactor is
immobilization onto support material (microorganisms
sticking to surfaces, eg. filter material in the "anaerobic filter")
or self-aggregation into pellets (microorganisms sticking to
each other, eg. sludge granules).
Anaerobic Contact Process This process consists of a
suspended-growth reactor, with
typical loadings in the range of 0.5
to 3 kg COD/m3/d.
The lower volumetric loading rate
allows the reactor to retain non-
granular flocculent biomass and to
treat wastewaters that have higher
COD, TSS and FOG than can be
handled by high-rate processes. handled by high-rate processes.
Effective for treatingwastewaters, such as potato processing, dairy and cheese,
yeast and distillery.
The larger volume of the system means that it occupies more land area;
Retains a large amount of biomass, which gives the process more stability and
robustness than higher rate systems.
The system can operate at lower temperatures than other processes and
generates less waste sludge on a dry weight basis.
Upflow Anaerobic Sludge-Blanket Process
Influent flow is typically equalized,
neutralized and partially acidified in a
separate tank ahead of the reactor.
The influent flow is often mixed with
effluent recycle and then distributed into
the lower part of the reactor below the
The upper portion of the reactor typically
has a gas-liquid-solids separator (GLSS)
that removes biogas and clarifies the
Up flow velocity : 0.6 0.9 m/h
Granules range in size
from 0.5-2.5 mm,
that removes biogas and clarifies the
UASB UASB reactors typically require low influent TSS concentrations (< 15 percent of the influent
COD concentration) and FOG concentrations (< 100 milligram per liter (mg/l)).
Concentration from 50-100 kg VSS/m3 at the bottom, to 5-40 kg VSS/m3 in the upper part of
OLR: 5-15 kg COD/m3/d
Significant parameters in the UASB operation are floe diameter, microbial density, and the
structure of the gas-solid separator which effectively retains the microbial granules within the
The criteria :
(a) selection of a suitable waste water capable of granule self-formation;
(b) operation of the reactor without mechanical agitation;
(c) start up at a relatively low COD load;
(d) use of waste water containing Ca2+ and Ba2+ and
(e) avoidance of bulking caused by filamentous microbial growth. Granule formation in a
UASB system is influenced by the growth of rod-type Methanothrix spp. which produce
Anaerobic Fixed Bed Process Rasio H/d = 1-2
Nozzle umpan : 5 10 m2
Kecepatan fluida 1-2 m/h
Rasio resirkulasi 5-10
Tinggi fixed bed max 7 m; keseluruhan reaktor max 14,5 m
OLR : 5-15 kg COD/m3/d.
used for removal of soluble organics and has similar loading used for removal of soluble organics and has similar loading
limits in terms of FOG (< 100 mg/l) and TSS (< 15 percent of
AnFB Full-scale UAFP systems (waste water can be treated at an HRT of 7.8 days with 74% COD
removal. Application of this UAFP to domestic sewage treatment using Raschig rings (2.5 cm)
as microbial supports, resulted in BOD removal of 50 to 60 % and suspended solids (SS)
removal of 70 to 80%, at an HRT ranging from 5 to 33 hours.
Selection of a medium in which microbial adhesion is greatly influenced both by SS, and the
chemical composition of the waste water, is extremely critical in UAFP systems. The effects of
physical medium characteristics, such as size and shape, on COD removal have been
investigated using modular corrugated blocks (porosity > 95%), pall rings, and perforated
At a COD load of 2 kg/m/day, modular corrugated blocks exhibited superior behavior,
removing 88 % of COD. A comparison of COD removal for cross- and tubular-flow systems,
reveals that COD removal is 20 to 30 % greater in cross-flow systems.
In addition to plastic media, baked clay and a melted slug have also proven useful in
laboratory experiments on methanogenesis from formate, acetate, and methanol. Pumice
was used as a microbial supporter for methanogenesis from methanol-rich waste water of
the evaporate condensate from a pulp mill (COD load: 12 kg/m3/day, COD removal: 96%).
Expanded Bed Process (Fluidized)
Media: Pasir, batu bara, agregat lain
Biomassa tumbuh pada permukaan media
Konsentrasi biomassa 15.000-40.000 mg/l
Rasio H/d = 5 25
Faktor kunci: fluidization zone distribusi Faktor kunci: fluidization zone distribusihomogen dead zone dan high shear force
Tinggi fluidized bed ditentukan oleh flow rate
Untuk mengurangi kehilangan media:
stationary support-biomass separation
device pada tinggi bed maximum (minimum
1,5 m dibawah overflow)
Mengatur kecepatan fluidisasi
OLR :10 - 25 kg COD/m3/d.
AnEB Use of artificial sewage in an AFBR, resulted in COD removal exceeding 80 % at 20C, an