Anaerobic digestion

Anaerobic Digestion
Presented by PureTerra Ventures

OVERVIEW
Overview History Process Technologies AD Systems O&M Advantages Drawbacks Applications Market Overview DealsRegulations

Anaerobic Digestion: Overview
3Sources: EPA, Geograph
What is AD? AD is a natural process in which microorganisms break down organic materials
What are “organic
materials”?
“Organic” means coming from or made of plants or animals. This may include
animal manures, food scraps, fats, oils & greases, industrial organic residuals
and sewage sludge (“biosolids”)
Where does it take
place?
Anaerobic digestion takes place in closed spaces where there is no air (or
oxygen), hence the name “anaerobic”
What is the result of
the process?
When microorganisms break down or eat the organic materials biogas is
generated. The material that is left after the process is called digestate which is
rich in nutrients and can be used as fertilizers/soil amendments
What is the result of
the process?
When microorganisms break down or eat the organic materials biogas is
generated. The material that is left after the process is called digestate which is
rich in nutrients and can be used as fertilizers/soil additives

HISTORY

History of AD
5Source: PennState Extension
Jan Baptita Van Helmont
determined that flammable
gases could evolve from
decaying organic matter
Principle Discovery
Count Alessandro Volta
concluded that there was a
direct correlation between
the amount of decaying
organic matter and the
amount of flammable gas
produced
Direct Correlation
Established
Sir Humphry Davy
determined that methane
was present in the gases
produced during the AD of
cattle manure
Methane Detected
First digestion plant was
built in Mumbai, India
First Digestion Plant
1600
s
1776
1808
1859

6Source: PennState Extension, Anaerobic Digestion and Bioresources Association
First dual-purpose tank for
both sedimentation and
sludge treatment installed
in Hampton
First Dual-purpose
Tank
The development of
microbiology as a science led to
research by Buswell and others
o identify anaerobic bacteria and
the conditions that promote
methane production
Identification of Anaerobic
Bacteria
China has 6 million small
scale digesters on farms
Traction in China
First in the USA - by Cornell
University
Plug Flow Digester
developed in USA
Biogas was recovered from a
"carefully designed" sewage
treatment facility and used to
fuel street lamps in Exeter
AD Reaches UK1895
1904
1930
s
1970
1978

7Source: Anaerobic Digestion and Bioresources Association
Renewables Obligation
introduced in England,
Scotland & Wales -
electricity suppliers to
increase production of
electricity from renewable
sources
UK Regulations
First legally-binding framework to
cut carbon emission. Sets 80%
cut in greenhouse gas emissions
by 2050
UK Climate Change Act
Feed-in tariffs for
renewable energy
introduced in the UK
UK Regulation Update
Defra’s Waste Review: AD realizes
“greatest environmental benefit”
of any treatment option for
inedible food wastes
Recognition of AD
Benefits
German Renewable Energy
Act passed into law setting a
feed-in tariff for electricity
production
German Regulations2000
2002
2008
2010
2011

PROCESS

Process Illustration
9Sources: Environmental and Energy Study Institute
Livestock
Waste
Crops
Waste-
water
Food
Waste
Anaerobic
Digester
Biogas
Digestate
Heat Electricity
Bio-
methane
Fuel Gas Grid
Fertilizers/Soil
Amendments
Livestock
Bedding

• Broadly, the Anaerobic Digestion process can be broadly segregated as a “two-stage” process as there are two types of bacteria each
relying on each other. These two stages are continuous processes till the second stage results in stabilization.
• In the first phase, organic material is changed by acid forming bacteria to simple organic matter
• In the second phase, methane-forming bacteria use organic acids to produce Carbon Dioxide and Methane. The acid is used in the
rate that it is produced.
• The digestion process results in the following products:
Process Overview
10Sources: Michigan Department of Environmental Quality, The Water Network
Gases which can be
utilized for heating
digester/buildings,
running engines and
for electrical power
Scum which are the
lighter solids floating
from gas entrapment.
If it builds up it can
reduce the capacity
Supernatant which is
the liquid high in
solids, BOD &
ammonia and
typically recycled
through the plant
Digested Sludge
which is the final
“stabilized” product
containing inorganic
solids and not easily
digested organic
solids

1 2 3 4
Detailed Stages in Anaerobic Digestion
11Sources: Anaerobic Digestion and Bioresources Association, Anaerobic Technology in Pulp and Paper by P. Bajpai, Washington State University Extension
Hydrolysis
Acidogenesis Acetogenesis Methanogenesis
Complex organic matter, Carbohydrates, Fats & Proteins are broken
down into glucose molecules, fatty acids and amino acids
This stage is carried out by hydrolytic eco-enzymes (such as cellulase,
amylase, protease and lipase) exerted by fermentative microorganisms
Some products of hydrolysis such as hydrogen and acetate may be
used by methanogens. However, majority of the molecules produced
are relatively large and must be further converted to smaller molecules
for production of methane
Relatively slow step - can limit the rate of the overall process
Carbs, Proteins
& Fats
Sugar, Amino
Acids & Fatty
Acids
Volatile Fatty
Acids
Acetic Acid
H2 and CO2
Methane &
Carbon dioxide

1 3 4
12
Hydrolysis
Acidogenesis
Acetogenesis Methanogenesis
Sources: Anaerobic Digestion and Bioresources Association, Anaerobic Technology in Pulp and Paper by P. Bajpai
2
Bacteria break down glucose molecules, fatty acids & amino acids into
volatile fatty acids & alcohols resulting in byproducts like hydrogen
sulphide, carbon dioxide and ammonia
The organic are converted by acid-forming bacteria to higher organic
acids such as propionic acid, butyric acid and to acetic acid, hydrogen
and carbon dioxide
Carbs, Proteins
& Fats
Sugar, Amino
Acids & Fatty
Acids
Volatile Fatty
Acids
Acetic Acid
H2 and CO2
Methane &
Carbon dioxide

1 4
13
Hydrolysis Acidogenesis
Acetogenesis
Methanogenesis
2 3
Volatile fatty acids & alcohols are converted into hydrogen, carbon
dioxide and ammonia
Higher organic acids produced during acidogenesis are subsequently
transferred to acetic acid and hydrogen by acetogenic bacteria
It is not always possible to draw distinctions between acidogenic and
acetogenic reactions. Acetate and hydrogen are produced during
acidification and acetogenic reactions and both of them are substrates
of methanogenic bacteria
Carbs, Proteins
& Fats
Sugar, Amino
Acids & Fatty
Acids
Volatile Fatty
Acids
Acetic Acid
H2 and CO2
Methane &
Carbon dioxide

1
14
Hydrolysis Acidogenesis Acetogenesis
Methanogenesis
2 3 4
Archaea convert hydrogen and acetic acid into methane and carbon dioxide
Methane is produced by methanogenic bacteria which are capable of
metabolizing formic acid, acetic acid, methanol, carbon monoxide, and
carbon dioxide and hydrogen into methane
The methanogenic bacteria are crucial to anaerobic digestion process since
they are slow growing and extremely sensitive to the changes in the
environment and can assimilate only a narrow array of relatively simple
substrates
Methanogenesis is a critical step in the entire anaerobic digestion process,
and its biochemical reactions are the slowest in comparison to those in other
steps. Methane-producing bacteria are strict anaerobes and are vulnerable
to even small amounts of oxygen
Carbs, Proteins
& Fats
Sugar, Amino
Acids & Fatty
Acids
Volatile Fatty
Acids
Acetic Acid
H2 and CO2
Methane &
Carbon dioxide

TECHNOLOGIES

AD Technologies Used Globally
16
Liquid Anaerobic Digestion
High Solids Anaerobic Digestion
Plug Flow Anaerobic Digestion
Micro Anaerobic Digestion
High Rate Anaerobic Digestion
Co-digestion
Sources: Maple Reinders, Geograph

Liquid Anaerobic Digestion
17Sources: Biogas World, Wales AD Centre
Some companies offering
Liquid Anaerobic Digestion Tech
• Designed to process a dilute organic slurry with typically <15% total
solids
• Successful track record in treating low solid materials such as
sewage sludges and food industry effluents
• Require comparatively larger digesters, more and greater capacity
water pumping and piping/valving, more extensive digestate storage
and / or de-watering, higher capacity wastewater treatment facilities
and more energy required to heat the larger volumes
• Providing that the above points are considered at the design stage,
a wet system can provide an effective and robust means of treating
low solid content waste, or high solid waste that has been adjusted
to <15% total solid content

High Solids Anaerobic Digestion
18Sources: Waste360
High Solids Anaerobic Digestion Systems
• High-solids systems can handle up to 35 percent solids, which could
be some materials other than organics, though at a
minimumSuccessful track record in treating low solid materials such
as sewage sludges and food industry effluents
• More expensive than liquid digestive systems
• Municipalities and waste haulers tend to select this system type
because of a higher solid, higher contaminant mix

Plug Flow Anaerobic Digestion
19Sources: Renewable Energy Institute
Plug Flow Anaerobic Digestion Tech
• Can be considered a type of high solids anaerobic digester - it can
handle greater amounts of solids than both a covered lagoon and a
complete mix digester
• Total solid content of input should be at least 15% to as high as 20%
• The contents within the plug flow digester are thick enough to keep
particles from settling to the bottom of the tank
• Plug flow digesters do not require mechanical mixing as in other
types of digesters
• Hydraulic retention times are generally in the 15 days to 21 day
time-frame

High Rate Anaerobic Digestion
20Sources: Environmental Energy & Engineering Co., Extension.org, American Biogas Council, Environmental Expert, Environmental Resources Center
High Rate Anaerobic Digestion Tech
• System where liquids stay in the digester for a short period of time;
where-as, solids are held longer. This allows for a smaller reactor
size, while maintain high gas production
• Decouples the hydraulic retention time (HRT) from the solids
retention time (SRT)
• Methane-forming microorganisms are trapped in the digester to
increase efficiency
• High rate systems are more commonly used and are characterized
by supplemental heating, auxiliary mixing, uniform feeding rates, and
sludge thickening before digestion

Micro Anaerobic Digestion
21Sources: Decisive2020.eu, Biogas World, Bioenergy Farm
Micro Anaerobic Digestion Tech
• Micro anaerobic digesters can be applied to anywhere where there
is a need and benefit for AD but a full-sized system wouldn’t be
appropriate because of cost and footprint constraints
• It is generally anticipated that micro scale biogas plants are on farm
installations using only own (waste) biomass resources, where
livestock manure is a main source
• Micro-scale digestion involves the production of biogas, but on a
small scale within farms
• The small-scale digestion production units are below 80 kW

Co-digestion
22Sources: IAState.edu
Co-digestion Tech
• Co-digestion is the simultaneous digestion of a homogenous mixture
of two or more substrates. Traditionally, anaerobic digestion was a
single substrate, single purpose treatment
• The most common situation is when a major amount of a main basic
substrate (e.g. manure or sewage sludge) is mixed and digested
together with minor amounts of a single, or a variety of additional
substrate
• The use of co-substrates usually improves the biogas yields from
anaerobic digester due to positive synergisms established in the
digestion medium and the supply of missing nutrients by the co-
substrates

AD SYSTEMS

Types of AD Systems
24Sources: South Dakota State University
There are many types of AD Systems depending on different classification methods as highlighted on this page
Classification
Methods
Loading Schedule
Flow Pattern
Mixing
Temperature Regime
HRT SRT
Batch Continuous
No Mixing
Complete
Mix
Mesophilic
Thermophili
c

Some of the Commonly Used AD Types
25Sources: Washing State University Extension, HoSt Bioenergy
Some of the commonly used AD System Types
Complete Mixed Reactors
Mixed Plug Flow Reactors
Covered Lagoons
Fixed Film Anaerobic Digester
Up-flow Anaerobic Sludge Blanket
Sequential Batch Reactor

Complete Mixed Reactor (CMR)
26Sources: South Dakota State University, Environmental Resources Center
Biogas
Effluent
Feed
Overview:
• Covered tank with mixing
• Heated
• Mesophilic or Thermophilic Range
• 15-20 Day HRT
• 2-10% Solids Input
Advantages:
• Efficient
• Can digest different levels of dry matter content
• May take energy crops
• Good mixing
• Good solids degradation
Disadvantages:
• No guarantee on how much time the material spends in the tank
• Mechanical mixing requirement

Overview
Horizontal plug-flow reactor design incorporates progressive steps of narrow vertical mixing using gas injections throughout the length of the
long rectangular channel
Advantages:
• Inexpensive
• Simple to operate
• Can take energy crops
Disadvantages:
• Hard top difficult to open to remove settled solids
• Membrane top subject to weather (wind and snow)
Mixed Plug Flow Reactors
27
Biogas
Effluent
Feed
Axial Mixing
Sources: Washington State University Extension, Environmental Resources Center

Overview
Anaerobic digester reactor design that is made up of a lined pit and a
flexible plastic cover. This system captures biogas under an
impermeable cover, while taking advantage of the low maintenance
requirement of a lagoon.
Advantages:
• Inexpensive
• Easily adapted to hydraulic flushing
• Simple construction and management
Covered Lagoon
28Sources: Washington State University Extension, Environmental Resources Center
Biogas
Feed
Effluent
Disadvantages:
• Poor mixing
• Poor energy yield
• Large footprint
• Cover maintenance impacts life of the system
• Solids settling reduces useable volume
• Bacteria can wash out if short circuiting occurs
• Limited to warmer weather or warm climates since digestion
depends on temperature

Up-flow Anaerobic Sludge Blanket
29Sources: Hindawi, South Dakota State University
Deflectors
Overview:
Anaerobic digester reactor design that uses an up-flow regime to develop
dense granular sludge, which allows for high volumetric loadings
Advantages:
• Provides high removal efficiency even at high OLR and low temperature
and therefore requires smaller reactor volume
• Simple construction and low operation and maintenance cost due to local
availability of construction material and other parts
• Simple construction and low operation and maintenance cost due to local
availability of construction material and other parts
Disadvantages:
• Needs post-treatment as pathogens are not removed completely
• Long startup time is required due to the slow growth rate of
microorganisms in case activated sludge is not amply available
• Odor, toxicity, and corrosion problem
Feed
Biogas
Sludge Blanket
Deflectors
Effluent

Fixed Film Anaerobic Digester
30Sources: Environmental Resources Center
Biogas
Effluent
Feed
Overview:
• A fixed film digester is essentially a column packed with media, such as
wood chips or small plastic rings
• Methane forming microorganisms grow on the media
• Manure liquids pass through the media
Advantages:
• Efficient
• Low bacteria wash out
• High gas production per volume
Disadvantages:
• Suspended solids must be removed
• Expensive
• Plugging of bacterial growth media
• Lower gas production due to removed solids
Treatment Media
Drain

Sequential Batch Reactor
31Sources: Environmental Resources Center
Storage Tank
Feed
Pump
Filling Tank Aeration
Reactor
Air
Pump
Settling Tank Effluent Tank
Overview
Variation on an intermittently mixed digester. Methane
forming microorganisms are kept in the digester by settling
solids and decanting liquid. It operates in a cycle of four
phases.
Advantages:
• High gas yield per substrate load
• Works well with dilute manure
• Small reactor size
• Can accept high energy liquid co-digestion products
Disadvantages:
• Complex orientation
• Relatively expensive
• Low gas yield per reactor volume
• Works best with low solids substrate

O&M

Factors Affecting Anaerobic Digestion
Sources: Environmental Information System, Michigan Department of Environmental Quality
Bacteria
Must have enough living organisms and the two different types bacteria types required in balance
Waste
Solid concentration and frequency of feeding can impact the process
Contact
Stabilization cannot occur without actual contact of the bacteria with the food. This contact can take place
in several ways but the most effective is mixing. Mixing can be achieved artificially by mechanical mixers or
by natural means.
Time
Two main factor may be considered in this aspect namely hydraulic retention time (HRT) and the solids
retention time (SRT). SRT depends on the degree of sludge retention achieved and HRT. The SRT/HRT
ratio, therefore, directly implies the efficiency of a treatment system. Higher the ratio, more efficient and
economic the system
Temperature
The rate of food stabilization increases and decreases with temperature within certain limits
pH
The pH of the contents of a digester depends on the relationship between the volatile acid, alkalinity and
percentage of carbon dioxide in the digester gas. Many reporters have indicated that the optimum pH for
the digestion of organic waste is in the range 6.8 to 7.2 with the limit of the range for operation without
significant inhibition being 6.5 to 7.6
pH
Toxics
Inhibitory effects of certain materials on digestion if their concentration become too high
33

Key Ops & Control Parameters
34Sources: Michigan Department of Environmental Quality, American Biogas Council, Water Environment Federation
Maintain adequate quantity & plan for restart
Minimize amount of inorganic entering and eliminate toxic material
Amount applied to the treatment process should be according to
system size
Bacteria
Food
Loading
Temperature strongly influences many factors affecting all stages of
microbial activity and especially methane and VFA production
Temperature
Methanogens are sensitive to variations in pH and it is critical to
maintain the correct pH range for efficient operations
pH
Sources of alkalinity like ammonia and bicarbonate are produced
during digestion and help maintain pH. A well-performing digester
should not require alkalinity supplementation
Alkalinity

Maintenance Overview
35Sources: Water Environment Foundation
Minimizing Tank Foaming
Foaming impairs performance by
reducing the active digestion
volume; this may lead to lower
volatile solids reduction and biogas
production, short circuiting of
pathogens, mechanical equipment
damage, and foam overflows or
spills. Foaming may result from the
presence of chemical surfactants,
biological surfactants, or
filamentous organisms. Foaming
may be exacerbated by unstable
operations such as highly variable
loading rates or mixing. Maintaining
constant digester feeding (rather
than loading in batches) helps limit
tank foaming issues
Minimizing Odor
Odorous compounds such as
hydrogen sulfide and ammonia are
produced during digestion. The
installation of digester tank covers
limits the effect of nuisance odors
to the surrounding environment
Tank Cleaning
Digester tanks should be removed
from service periodically for
cleaning and inspection. While
offline, operators can check or
repair any mechanical equipment
installed within the tank and
inspect the tank itself for structural
deterioration. Additionally, grit and
scum, accumulates within digestion
vessels and limits
effective/treatment volume, and
should be removed while the tank
is offline.
Maintaining Safe Workspaces
Biogas is a flammable substance.
The lower explosive limit (LEL) for
methane in the air is 5%.
Furthermore, empty digesters are
classified as confined spaces. The
immediately dangerous to life or
health (IDLH) limit for methane in
the air is 0.5%. To ensure safety
and minimize risk, air monitors
should be installed where
appropriate and operators should
follow all safety precautions when
working around digesters and
related equipment.

Other Maintenance Practices
36Sources:Exploring Energy Efficiency & Alternatives
Maintenance Item Description Frequency
Sludge Removal
An anaerobic digester system must be cleaned and removed of excess sludge. In well-designed systems, this is performed
automatically with very little downtime. Other designs require manual removal of waste
1 to 2 years
Pump Clearing When pumping high solids content waste, it is important to ensure that pumps are cleared of debris regularly
3 to 6
months
Iron Packing Replacement
It is important to remove the corrosive hydrogen sulfide compounds to avoid engine replacement if biogas collected from the
digesters is being refined and used for electricity generation. This can be done by passing the biogas through iron packing
material.
6 to 12
months
General Engine Maintenance The generator producing electricity from the anaerobic digester must be inspected for proper fluid levels Weekly
Preventative Engine Maintenance The electrical, fuel and air intake systems must also be inspected for each of the gen sets Monthly
Valve Leak Checks
To avoid safety hazards, it is recommended that the valves on the digestion system be checked for leaks one to two times a
year. Improperly working valves should be replaced as soon as possible
6 to 12
months
Pipe Leak Checks
Pipes must be checked for leaks at least once per year. It is also important that no open flames are anywhere near inflow or
outflow pipe lines.
6 to 12
months
Fittings Leak Checks Any nonmetal fitting (i.e. ducted vents, plastic valves, rubber fittings) located on the gas or waste pipeline must be inspected
6 to 12
months

ADVANTAGES

Advantages of Anaerobic Digestion
38Sources: Cleantech Loops
Environmental Benefits
• Elimination of malodorous compounds
• Reduction of pathogens
• Deactivation of weed seeds
• Production of sanitized compost
• Decrease in GHGs emission
• Promotion of carbon sequestration
• Beneficial reuse of recycled water
• Protection of ground/surface water
Energy Benefits
• Net energy producing process
• Biogas facility generates high quality
renewable fuel
• Surplus energy as electricity and heat is
produced
• Reduces reliance on energy imports
• Such a facility contributes to decentralized,
distributed power systems
• Biogas is a rich source of electricity, heat,
and transportation fuel
Economic Benefits
• Transforms waste liabilities into new profit
centers
• Time devoted to moving, handling and
processing organic waste is minimized
• Adds value to negative value feedstock
• Income can be obtained from the
processing of waste (tipping fees), sale of
organic fertilizer, carbon credits and sale of
power
• Power tax credits may be obtained from
each kWh of power produced
• Biomass-to-biogass reduces water
consumption
• Reduces dependence on energy imports

DRAWBACKS

Drawbacks of Anaerobic Digestion
40Sources: D Hill Environmental
Slow start up
Close monitoring required
Sensitive to temperature,
load and toxicity
High BOD and P in
supernatant
Cleaning & maintenance
difficult with sealed tanks
Heating, mixing, gas collection
equipment & plumbing adds cost,
complexity
Extreme confined space
hazard
Production of explosive
gas

APPLICATIONS

Some Industrial Applications of AD
42Sources: Anaerobic Digestion: Industrial Applications by D.Nally, S.Smith, F.Hackett, H.Mooney; EPA, Sciencing, Republic Sales, Urban News Digest, LookForDiagnosis
Municipal
Solid Waste
Management
Wastewater
Treatment
Plants
Food &
Dairy
Industries
Pharmaceutical
Industry
Chemical
Industry

Municipal Solid Waste Management
43Sources: Anaerobic Digestion: Industrial Applications by D.Nally, S.Smith, F.Hackett, H.Mooney
• Treatment of municipal solid waste is a major challenge of modern society
• This waste is associated with pollution, bad odors and high expenditure
• Simultaneous digestion of organic fraction of municipal solid waste together with sewage sludge under mesophilic conditions is regularly used in
several countries
• This process is routinely performed, after rough screening, by conveying the solid waste to a WWTP where it is partially treated
• The resulting mixture is then submitted to digestion
• Although the process for this specific application has been available since the mid 1980s, most of the initial commercial application was limited to
Europe driven by higher dependency on foreign oil (and hence greater stress on alternative fuel), higher fossil fuel prices and severe land space
constraints

Wastewater Treatment Plants
44Sources: Dartmouth
• Anaerobic digestion of municipal wastewater sludge has been widely practiced since the early 1900s and is
the most widely used sludge treatment method
• Overall, the process converts about 40% to 60% of the organic solids to methane (CH4) and carbon
dioxide (CO2)
• The residual organic matter is chemically stable, nearly odorless, and contains significantly reduced levels
of pathogens
• The suspended solids are also more easily separated from water relative to the incoming sludge or
aerobically treated sludge (such as in outdoor pond)
• The treatment of wastewater sludge, from both primary and secondary treatment steps, consists of two
main phases
• In the 1st step, all incoming flows of sludge are combined, and the mixture is heated to a mild temperature
(about body temperature) to accelerate biological conversion. The residence time here ranges from 10 to
20 days
• In the 2nd tank, the mixture is allowed to undergo further digestion. There is no longer active mixing in order
to promote separation, and there is no need of heating as the process generates its own heat
• In further processes the settled sludge is dewatered and thickened. The goal is to separate as much water
as possible to decrease the volume of material. Finally, a phase known as sludge stabilization reduces the
level of pathogens in the residual solids, eliminates offensive odors, and reduces the potential for
putrefaction

GREAT LAWRENCE SANITARY DISTRICT
(GLSD), MASSACHUSETTS & NEW HAMPSHIRE
45Sources: Water & Wastes Digest
CASESTUDY
• GLSD serves the following localities: Lawrence, Andover, Methuen, North Andover and Dracut, Mass., and Salem, N.H.
• GLSD’s treatment facility is capable of processing up to 52 million gal per day (mgd) of wastewater, with the average daily flow
typically at 31 mgd
• The treatment system includes primary sedimentation, biological oxidation, secondary clarification and treated effluent chlorination
• Built in 2002, GLSD’s system features three anaerobic digesters for a total capacity of 4.2 million gal
• At GLSD, the biogas is used to maintain digester temperatures, and for onsite sludge drying and pelletizing
• Originally, the excess gas was captured and flared. Today, it is being used productively for building heating and domestic hot water
• The plant added two new boilers with dual-fuel burners capable of burning both biogas and natural gas
• These boilers use less water and produce steam more efficiently, largely replacing older ones that operate on natural gas and fuel oil
• Burning biogas for building heating and hot water makes use of an energy resource produced on site, while also reducing a
dependence on fossil fuels
• Furthermore, the upgrades lead to a decrease in the flaring of biogas, which reduces greenhouse gas emissions
• The GLSD project is proving that wastewater treatment plants can be an untapped source of renewable energy. It also serves as an
example of how being diverse with renewable energy projects can yield tremendous economic and environmental value. In a time of
high energy costs and endless discussions regarding global warming, renewable energy success certainly is most welcome.

Food & Beverage Industry
46Sources:Biocycle
• Because of more stringent processing and sanitation requirements, the volume of food production and processing waste has increased in recent
years
• Disposal can be difficult for food processors due to rising hauling costs, as well as more stringent practices for animal feed and land application
• At the same time, rising wastewater surcharges, utility costs and consumer pressure for products to be “green” are leading food processors to
pursue on-site anaerobic treatment and energy recovery as an option for food waste
• Another trend is forming partnerships with other food producers and/or with local municipalities to provide mutually beneficial codigestion
opportunities, utilizing existing or new anaerobic digester infrastructure
• Applications have been primarily limited to the following: High rate technologies for liquid carbohydrate wastes with low solids; Lagoon type
applications for higher solid wastes where land is available; and medium rate conventional mixed technologies for wastes containing fats, oils,
greases and moderate solids. The high-rate technologies are the most common application of the three listed
• Europe has been practicing high solids digestion for years. The primary driver has been the ban on organic waste disposal to landfill and land
application as well as preferential prices paid for the generated energy
• Since it is not part of most food producers’ core business to own or operate AD facilities, opportunities are mostly being pursued as design-build-
own-operate (DBOO) projects by developers, with the main goal of reducing overall operating costs to produce food
• AD waste to energy projects are a great opportunity for the food and beverage market to recycle food waste to create renewable energy as well
as other beneficial by-products – and to make their impact on the sustainability of the environment

HYDROTHANE + NORTH BRITISH DISTILLERY
47Sources: Anaerobic Digestion and Bioresources Association
CASESTUDY
• The North British Distillery Co Ltd. (NBD) worked with HydroThane UK to work on construction of high rate anaerobic digestion
technology
• The installation was done in the Company’s central Edinburgh distillery site and comprised of 3 x 500 cu. m. ECSB reactors
• The project parameters and considerations were as follows: Feed post distillation liquor, COD Load 27,000Kg/day, Producing
450Nm3/hr biogas, Energy output >3 MW/hr total, 500kW CHP unit producing electricity, FIT’s income, Boiler producing steam at 10
barG, Reduction in gas and electricity imports and Increased spirit production
• Benefits for NBD were as follows:
• Reduced natural gas imports resulting in reduced energy costs
• Reduced carbon dioxide emissions by between 9,000 to 10,000 tonnes per year - reduced carbon footprint
• Reduced load on existing by-products evaporation process - increasing overall production capacity
• Reduced on-going water and effluent charges

Dairy Industry
48Sources:International Journal of Applied Environmental Sciences
• Dairy industries discharge wastewater which is characterized by high chemical oxygen demand, biological oxygen demand, nutrients, and organic
and inorganic contents. Such wastewaters, if discharged without proper treatment, severely pollute receiving water bodies
• For treatment of dairy waste water, several physical, chemical and biological methods are available. However, dairy waste responds best to the
biological treatment
• The dairy wastewater consists of high organic matters, mainly Lactose, fat and protein. A suitable environment for Lactobacillus species is formed
due to fortified nutrients in cheese whey which is useful in converting organic sources into methane via anaerobic process
• Anaerobic treatment process is an appropriate technique for the bioconversion of dairy wastewater into biogas

ANAEROBIC DIGESTER AT SPRING VALLEY
DAIRY
49Sources: CORNELL
CASESTUDY
• Traditionally, manure generated at Spring Valley Dairy was stored in a concrete manure storage pit and spread on crop fields.
However, this manure management practice can potentially cause pollution to water and air, including water quality problems,
dust, smog, greenhouse gases (methane), and odors
• Faced with the potential of increasing federal and state regulations on animal waste, Spring Valley Dairy looked for alternative
practices. The search quickly landed on anaerobic digestion technology
• The digester system at Spring Valley Dairy is composed of several subsystem: Manure collection, Activation system, Covered
manure storage, Engine generator set and Flare
• With 236 animals on the farm, the manure production is about 3,400 gallons per day. The manure utilizes gravity to flow from the
barn collection system to the manure pit, from which it is pumped into the activation system
• These consist of two seed digesters with a capacity of 1,000 gallons each. The converted manure storage pit has a capacity of
300,000 gallons. A flexible, impermeable cover added to the top of the pit traps the biogas
• The retention time is 20 days for the activation digesters and 90 days for the manure storage pit
• Based on the cost-benefit analysis, the annual net cost is about $22.93/cow/year for odor control and waste stabilization
• Since the installation of the anaerobic digester system on Spring Valley Dairy, the odor from manure handling and spreading has
been greatly reduced. The nutrients in manure are also controlled and the pathogens are likely also reduced

Pharmaceutical Industry
50Sources:International Journal of Chemical Engineering and Applications, Vol. 2, No. 1
• Effluents from manufacturing operations in the pharmaceutical industry, such as antibiotic formulation, usually contain recalcitrant compounds
• An approach towards appropriate technology for the treatment of pharmaceutical wastewaters has become imperative due to strict water quality
legislation for environmental protection
• Typically, pharmaceutical wastewater is characterized by high chemical oxygen demand (COD) concentration, and some pharmaceutical
wastewaters can have COD as high as 80,000 mg.L-1
• Due to high organic content, anaerobic technology is a promising alternative for pharmaceutical wastewater treatment

ADI SYSTEMS + ABBOTT LABORATORIES
51Sources: Evoqua/ADI Systems
• Abbott Laboratories is an American pharmaceuticals and health care products company headquartered in North Chicago, Illinois,
USA. The company operates in over 130 countries worldwide
• Abbott Laboratories needed to investigate the anaerobic treatability of its plant’s bacillus thuringiensis (BT) and fermentation
wastewater. ADI Systems was commissioned to carry out a pilot study on the wastewater generated at its pharmaceutical operation
• ADI Systems’ pilot study was such a success, it led to the design and construction of a full-scale low-rate anaerobic ADI-BVF® system
for Abbott Laboratories
• Results:
• System is simple to operate, cost-effective, and most importantly, provides reliable pretreatment of this difficult-to-digest
pharmaceutical wastewater
• The anticipated savings in sludge handling and disposal costs was a major driving force in the decision to choose ADI Systems’
technology
• The floating cover on each of the BVF reactors not only collects valuable biogas, but also helps control odors and temperature
• The biogas produced is used in plant boilers, helping to save on heating costs
CASESTUDY

Chemical Industry
52Sources: Awaleh MO, Soubaneh YD (2014) Waste Water Treatment in Chemical Industries: The Concept and Current Technologies
• During the last two decades large scale environmental initiatives have taken place in Europe and the
United States, these have resulted in strict environmental regulations on the industrial emissions for the
chemical industry
• Chemical industrial wastewaters usually contain organic and inorganic matter in varying
concentrations. Many materials in the chemical industry are toxic, mutagenic, carcinogenic or simply
almost non-biodegradable. This means that the production wastewater also contains a wide range
of substances that cannot be easily degraded
• Anaerobic processes have higher capital and operating expenses than aerobic processes because the
anaerobic systems must be closed and heated. Thus, anaerobic bioprocesses for treatment of
hazardous wastewater streams are typically limited to treatment of low-flow-rate streams such as
industrial effluent
• Anaerobic organisms have recently been shown to be responsible for a number of reductive reaction
processes that could have a significant impact on the treatment of certain classes of hazardous
compounds. In particular, anaerobic organism have been shown to be capable of reductively
dehalogenating a number of toxic compounds, such as chlorinated aromatics, that are very recalcitrant
to aerobic degradation
• Both aerobic and anaerobic treatment systems are feasible to treat wastewater from all types of
industrial effluents. However, a combination using an anaerobic process followed by an aerobic
treatment system is a better option, as it can make use of the advantages of both the treatment
processes. Those hybrid systems produce a high removal of toxic pollutants

ADI SYSTEMS + TAE KWANG POLYESTER
PLANT IN KOREA
53Sources: Evoqua/ADI
CASESTUDY
• The Tae Kwang plant had an activated sludge system which was not meeting performance expectations due to overloading
• To overcome this, Tae Kwang investigated separating out the high-strength ethylene glycol waste stream and pretreating it
anaerobically to reduce the load on the activated sludge system
• A successful in-house pilot study confirmed the anaerobic treatability of the ethylene glycol waste stream
• ADI was selected for the project
• Results:
• The compact design of the ADI® hybrid reactor allowed it to fit into the small space available at the waste treatment site in Ulsan
City
• The higher solids inventory in the hybrid reactor results in longer sludge retention times (SRTs). Longer SRTs improve the reactor’s
ability to handle higher levels of toxic substances, shock loadings, and influent suspended solids
• The COD removal rate is estimated at 80%

REGULATIONS

The following section reproduces relevant content from the Global Methane
Initiative’s Report titled “A Global Perspective of Anaerobic Digestion Policies and
Incentives” published in November, 2014.
The full report can be found on Global Methane Initiative’s website and gives
deep insight into the subject matter.
Please note that some of the regulations mentioned here may have undergone
amendments since the original report was published.

Comprehensive Agriculture Policies And
Regulations
56Sources: A Global Perspective of Anaerobic Digestion Policies and Incentives - Global Methane Initiative
“Most environmental and agricultural agencies have
established a suite of agriculture and livestock
production policies and regulations that include
provisions for air emissions, water discharge and
nutrient management. Anaerobic digestion projects
are associated with several of these agricultural waste
streams.
Effective management of wastes generated from an
AD project can eliminate direct waste discharges to
the environment. Additionally, direct discharge of
waste to the land, a water body or to the atmosphere
usually requires the facility to meet permitting
requirements and obtain permission from a regulatory
agency”

Policies and Regulations Globally
“Regulatory frameworks for agriculture and renewable energy are important factors that influence the adoption and implementation of anaerobic digesters as well as the availability of
specific feedstock materials. Well-developed regulatory and policy frameworks encourage owners and developers to implement renewable energy systems and, in the context of this
report, anaerobic digester systems in the agricultural sector. Interest in AD has increased globally as governments work to reduce greenhouse gas emissions and identify alternative
energy sources for growing populations.” - Global Methane Initiative

Air Emissions From Farms
“Anaerobic digesters are not emissions-free. Digesters can generate air contaminants either directly via the digestion process, or indirectly via combustion of the gas generated
from the anaerobic digester. Air emissions can be discharged from flares, boilers or from cogeneration equipment, but these discharges can be managed with pollution control
devices. ”

Water Emissions
“Agricultural operations; in particular, the
animal wastes from livestock operations,
are one of the leading contributors to water
pollution. AD systems offer an effective
means to manage animal wastes and the
digestion process produces a digestate
(liquid effluent) that can be used
beneficially as fertilizer. However, the AD
process also produces water emissions
and if improperly managed, water
discharge from a digester can impair
groundwater and surface water quality ”

Manure Storage
“More than half of the countries examined for
this report have instituted manure management
policies that outline the collection, storage and
processing of livestock manure to prevent
surface and groundwater contamination as well
as reduce nuisance odors. Typically, manure is
stored in various holding facilities on farms for
several months and then used as fertilizer. By
instituting policies on manure storage, countries
encourage use of AD systems to mitigate odor
while providing storage”

Nutrient Management
“Nutrient management policies, in place in 16
out of 30 of the countries reviewed, encourage
AD system implementation because the use of
digestate as a fertilizer provides farmers with
greater flexibility in regards to time and areas of
application. Additionally, AD is effective at
pathogen reduction, and applying digestate
instead of untreated manure to agricultural fields
reduces the likelihood of surface water
pathogen contamination from the application of
manure”

Renewable Energy-Related Policies And
Regulations
“Countries typically regulate energy production through a collection of statues, regulations, polices and common law. Many countries have developed or are starting to develop national
policies or laws that specifically address renewable energy sources. Most renewable energy regulations focus on solar power, wind power, hydropower and power from biomass (which
includes AD).”

Country Level Energy Planning
“Comprehensive and holistic ways of
planning and implementing energy actions at
the national level have been developed for
many countries. Action plans in several
countries include a commitment to increase
energy output from livestock manure
processed at AD facilities, while other
countries discuss energy planning in terms of
biogas.”

Countries That Use Incentive to Encourage AD

MARKET OVERVIEW

Market Overview
66Sources: bcc research
$6.10bn
$10.10bn
0
2.75
5.5
8.25
11
2017 2022
Global Market for AD Equipment
The growth in the global AD disinfection market is anticipated to be driven primarily by the regulatory environment
95%
of the 2022 market size will be
attributable to landfill gas,
agriculture, food and municipal
wastes
11.4%
CAGR through 2022 will make
wastewater/sludge and industrial
applications the highest growth
sub-segment in the global AD
markets

Some Key Players in the Global AD + Biogas
Ecosystem
67

DEALS
Overview History Process Technologies AD Systems O&M Advantages Drawbacks Applications Market Overview Deals

M&A Deals: 2018
69Sources: Company Website, Press Release, Biofuels Digest, RenewablesNow, Bureau van Dijk
Acquiring Company Target Deal Year Acquired Company Info Deal Value
3i Infrastructure Attero 2018 Owns and operates waste-to-energy plants €201 million
Eggersmann Farmatic GmbH 2018 Biogas tank manufacturer Undisclosed
Altri EDP Bioelectrica 2018 Electric power production using forest biomass €55 million
JLEN Egmere Energy/Grange Farm Energy 2018 Biogas plant $48 million
Clearfleau EnviroChemie 2018 On site waste-to-energy plants Undisclosed
Singleton Birch PlanET-Biogas 2018 Biogas plant manufacturer Undisclosed
M&A Deals: 2017
Evoqua ADI Systems 2017 AD systems design & manufacturing Undisclosed
Wärtsilä Corporation Puregas Solutions AB 2017 Turnkey biogas upgrading solutions €29 million
Convergen Energy 4 Biogas Plants from EuroEnergy 2017 Biogas plant Undisclosed
Gardner Denver LeROI Compressors 2017 Manufacturer of gas compression equipment and solutions for vapor recovery, biogas, etc $20 million
Premier Tech Aqua Brisanzia Technologies 2017 Water Management products & services Undisclosed
Republic Services ReCommunity Holdings 2017 Recycle processing Company Undisclosed
Gasum Swedish Biogas International 2017 Biogas producer and supplier Undisclosed
Suez GE Water 2017 Water technologies & solutions €3.2 billion
Direct Energie SA Quadran SAS 2017 Biogas Production $484 million

M&A Deals: 2016 & Earlier
70
Asia Biogas Thai Biogas Energy Co 2016 Biogas company Undisclosed
Hitachi Zosen Inova Etogas 2016 Power-to-gas plants and systems Undisclosed
Hitachi Zosen Inova BioMethan 2016 Gas upgrading technology Undisclosed
Blue Sphere Agrilandia Societa Agricola a r.l. 2016 1MW Biogas Plant $4.5 million
Harvest Power Smithers Enterprises 2016 Waste recycling - wood Undisclosed
Stantec Inc. MWH Global 2016 Water and Wastewater Management, Construction, Engineering $793 million
Gasum Biovakka Suomi Oy 2016 Biogas plants Undisclosed
Suez Prodeval 2016 Biogas technology Undisclosed
Ebara Thebe Bombas Hidráulicas 2015 Pumps manufacturer Undisclosed
Hitachi Zosen Inova Kompogas 2014 Waste to energy plant Undisclosed
GE Monsal 2014 Water, waste, advanced anaerobic digestion and integrated biogas-to-energy business Undisclosed
Gasum Skangass 2014 LNG Distribution Undisclosed
EDF Renewables Heartland Biogas Project 2013 Biogas plant Undisclosed
Sources: Company Website, Press Release, Biofuels Digest, RenewablesNow, Bureau van Dijk

REFERENCES
Overview History Process Technologies AD Systems O&M Advantages Drawbacks Applications Market Overview Deals

REFERENCES & SOURCES
72
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• “Anaerobic Digestion Fundamentals Fact Sheet.” Water Environment Federation, 2017.
• “Anaerobic Sludge Digestion Process.” Michigan Department Of Environmental Quality.
• Awaleh MO, Soubaneh YD (2014) Waste Water Treatment in Chemical Industries: The Concept and Current Technologies. Hydrol Current Res 5: 164. doi:10.4172/2157-
7587.1000164
• Bajpai, P. Anaerobic Technology In Pulp And Paper Industry. Springer Singapore, 2017.
• “Basic Information About Anaerobic Digestion (Ad).” United States Environmental Protection Agency, Epa, Www.Epa.Gov/Anaerobic-Digestion/Basic-Information-About-Anaerobic-
Digestion-Ad#Howadworks.
• “Case Study: Hydrothane - North British Distillery.” Adba | Anaerobic Digestion & Bioresources Association, Adbioresources.Org/Library/Case-Studies/Case-Study-Hydrothane-
North-British-Distillery.
• Chelliapan, S., Et Al. “Anaerobic Pre-Treatment Of Pharmaceutical Wastewater Using Packed Bed Reactor .” International Journal Of Chemical Engineering And Applications, Vol.
2, No. 1, Feb. 2011, Pp. 32–37., Doi:Issn: 2010-0221.
• Costa, Allison, Et Al. “Anaerobic Digestion And Its Applications.” United States Epa, Oct. 2015.
• “A Global Perspective Of Anaerobic Digestion Policies And Incentives.” Global Methane Initiative - Agriculture Subcommittee, Nov. 2014.
• Hamilton, Douglas W. “Andig3: Types Of Anaerobic Digesters.” Environmental Resources Center.
• “History Of Ad.” Anaerobic Digestion And Bioresources Association, Anaerobic Digestion And Bioresources Association, Adbioresources.Org/About-Ad/History-Of-Ad/.
• Karidis, Arlene. “Comparing High-Solids And Low-Solids Anaerobic Digestion.” Waste360, 26 Dec. 2017, Www.Waste360.Com/Anaerobic-Digestion/Comparing-High-Solids-And-
Low-Solids-Anaerobic-Digestion.
• Kurt Hjort-Gregersen, Market overview micro scale digesters, BioEnergy Farm II publication, AgroTech A/S, Denmark, 2015
• “Liquid Digestion Systems.” Biogasworld, Www.Biogasworld.Com/Product-Category/Anaerobic-Digestion/Liquid-Digestion-System/.
• M. K. Daud, Hina Rizvi, Muhammad Farhan Akram, et al., “Review of Upflow Anaerobic Sludge Blanket Reactor Technology: Effect of Different Parameters and Developments for
Domestic Wastewater Treatment,” Journal of Chemistry, vol. 2018, Article ID 1596319, 13 pages, 2018. https://doi.org/10.1155/2018/1596319.
• Marjolaine. “What Is The Future Of Small-Scale Anaerobic Digestion? • Biogasworld.” Biogasworld, 4 Oct. 2017, Www.Biogasworld.Com/News/Future-Small-Scale-Anaerobic-
Digestion/.

REFERENCES & SOURCES
73
• Martin, Sarah. “High Solids Digestion In The Food And Beverage Industry.” Biocycle, May 2010, Www.Biocycle.Net/2010/05/17/High-Solids-Digestion-In-The-Food-And-Beverage-
Industry/.
• “Micro-Scale Anaerobic Digestion.” Decisive2020, Www.Decisive2020.Eu/The-Project/Micro-Scale-Anaerobic-Digestion/.
• Mitchell, Shannon M., Et Al. “Anaerobic Digestion Effluents And Processes: The Basics.” Fs171E, 2015.
• Nally, D., Et Al. “Anaerobic Digestion: Industrial Applications.” Institute Of Technonology Sligo.
• Nazaroff, And Alvarez-Cohen. “Anaerobic Digestion Of Wastewater Sludge.” Dartmouth.
• “Plug Flow Digester.” Plug Flow Digester | Anaerobic Digester | Anaerobic Digestion | Plugflowdigester.Com, Www.Plugflowdigester.Com/.
• Shete, Bharati Sunil, And N.P. Shinkar. “Anaerobic Digestion Of Dairy Industry Waste Water - Biogas Evolution-A Review .” International Journal Of Applied Environmental
Sciences , Vol. 12, No. 6, 2017, Pp. 1117–1130., Doi:Issn 0973-6077.
• “A Short History Of Anaerobic Digestion.” The Pennsylvania State University, The Pennsylvania State University, Extension.Psu.Edu/A-Short-History-Of-Anaerobic-Digestion.
• “Types Of Anaerobic Digesters.” Extension, Articles.Extension.Org/Pages/30307/Types-Of-Anaerobic-Digesters.
• Wei, Wu. “Anaerobic Co-Digestion Of Biomass For Methane Production: Recent Research Achievements.” Ia State.
• “Wet And Dry Anaerobic Digestion Systems.” The Wales Centre Of Excellence For Anaerobic Digestion | Single & Multistage Systems, Www.Walesadcentre.Org.Uk/Ad-
Information/Technologies/Wet-Dry-Systems/.
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