Minutes note for the Biochain study tour
Date: 23 – 24 January 2014
Name: Quan Van Nguyen, PhD student
Department of Plant and Environmental Sciences,
University of Copenhagen
nguyen@plen.ku.dk
1. Fredericia Central Wastewater Treatment Plant
Administration
Boilling systems
Biogas reactors
Organic matters
Pumping
systems
Loading stage
Electricity Generator
station (DONG energy)
Figure 1: Fredericia Biogas plant (Source: Annemarie Gotfredsen´s presentation, Director)
General information:
Fredericia Central Wastewater Treatment Plant or Fredericia biogas plant, which is located in Fredericia
region about 200 km west of Copenhagen, is second biggest biogas plant in Denmark. It is owned by
the Municipality of Frederica. The biogas plant has around 40 employees divided into 3 different
functional sections and management department (Figure 2).
Vision
 Become 1 of 10 most effective Danish company (best performing company) measured by
Supply Secretariat benchmark in 2014
 Become energy neutral by 2019
 Become a processing plant
 Increase the production of biogas (30%) by 2019 (?!)
Quan Van Nguyen
nguyen@plen.ku.dk
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Board of Directors
Manager
Administration
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Wastewater
Transport
Pipes Operation
treatment
15 (16)
Figure 2: Organisation of Fredericia Biogas plant (Source: Annemarie
Gotfredsen's presentation, Director)
Production
Annually, this biogas plant treats around 4,000 tones dry matter of wastes (65% of industrial wastes
including dairy industry and others industrial sectors, 35% of household waste of Fredericia region),
produced 6,900 tons of dewatered sludge, 25% TS. In 2013, the bio-plant treats approximately 9,3
million m3 waters, produced 1,7 million m 3 of biogas and 500,000 kwh electricity. In which, 0.7 million m 3
is used for heating water, the rest is used to produce electricity (?!).
The annual cash turnover approximately 100 million DKK. The fixed assets are about 2.5 billion DKK. In
2013, Wastewater Rate per. m 3 is around 18.80 DKK.
Fredericia biogas plant has 140 pumping stations spread around the city/town. Sewage and household
wastes are transported to the biogas plant by pipes and pumping systems. The current pumping rate is 5
m3 per hour.
The current end productions of this biogas plant are mainly biogas, and electricity (sell to DONG
energy), treated/ clean water. The overall cycle production of this biogas plant is represented in Fig 3.
Figure 3: Production cycle of Fredericia biogas plant (Source: Annemarie Gotfredsen's presentation, Director)
2. Foulum research center, Arhus University
Research interests and trend
Quan Van Nguyen
nguyen@plen.ku.dk
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Søren O. P represented his research group presented some researches outcomes that can be
considered as references for research activities in WP4. Most of the presented research are
related to N2O emission and mitigation of methane production related crop production.
Future research will focus on N2O emission from animal wastes, digestates slurry after field
application. Also, examining effects of treatment methods (untreated, digestated and
separated) on N2O emission.
Foulum Biogas plant
Feeding system:
 Feedstock input for biogas includes pig manure/slurry and dairy cattle wastes (prime
substrate), and maize/grass silage and straw (co-substrate).
 Feedstocks are prepared (break down or mill) and loaded/pumped into a 600 m3 digester 9
times per day.
 A big biogas reactor is set up out-door at approximately 52oC, with the retention time are
approximately 14 days.
Digestate
Normally, all digestates are storaged in two 5,000 m3 tanks for 30 days. Biogas production from these
storage tanks are low.
3. Maabjerg Biogas plant
General information
Maabjerg Biogas plant or Maabjerg BioeEnergy is one of the biggest Biogas plant in the world. The
BioEnergy facility is built to receive manure, energy crops (potato pulp), biowaste, and sludge from the
local sewage treatment plant around 20 km. This biogas plant is a complex Bioenergy manufactory
which produces electricity, gas, and fertilizes, also ethanol (in planned). This Biogas plant is facilitated
in 2011 and start working from 2012.
Figure 4: Maabjerg BioEnergy site
Production
Inputs (feedstock supply)
Quan Van Nguyen
nguyen@plen.ku.dk
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Feedstock for the plant is supplied by livestock farms, crop productions residues, sewage
sludge in the region. Feedstock from livestock farms often is storaged in storage tank at farm
before transported to the Biogas plant by special truck.
In average, slurry as feedstock supply has around 30% water (liquid fraction).
According to Alan Lunde (2013)1, feedstock supply for the biogas plant containing 550.000 tons
(fresh weight?!) from livestock farms (30% from dairy cattle farms, and the rest from pig
farms), 120,000 tons biological industrial waste (come mainly from slaughterhouses industry,
and food processing manufactories), sewage sludge which contain 35% solid fraction
contributes to 120,000 tons, and 2,000 tons of crops residues.
Straw is used as co-substrate in the biogas plant, which contributes about 150,000 to 155,000
tons straw per year.
Total organic nitrogen input is estimated approximately 780 tons per year.
Biogas systems
 After being delivered to the biogas plant feedstock (slurry) is pumped into a large 2.000 m3
tank. Then the slurry is pumped through pipelines to sanitation in batches of 60 tons,
remaining for an hour at 73oC for sanitation purpose. Afterward, the slurry is pumped into one
of 8 reactor tanks (8.000 m3 volume).
 The heat from the slurry is exchanged between sanitation batches and 8.000 m3 reactor tanks.
Therefore, the system can minimize the heat needed for heating up cold slurry (normally at
20oC from farms) to save energy using to heat up the reactors.
 The slurry is retained in the reactors for 23 days after be returned to farms (liquid fraction or
digestate) and provide solid fraction to DONG energy for burning.
 Gas production is produced from biogas plant is storaged at two storage tanks (10,000 m3
volume each) for maximum 3 days (?!).
 The biofilters are facilitated at the square building in the central (middle) of the site which will
clean the air inside the complex building, and reduce odor from possible wastes leached. The
capacity of pumping systems are 60,000 m3 air per hour.
Outputs
 All biomasses input will be treated and digested by biogas systems and produce biogas.
 The end products of this biogas plant, however, can be recognized at three main forms:
electricity, gas and heat. The solid fraction after digested in biogas digesters is the residue.
 Ethanol, however, may be one of the most important products of this bioenergy in the future
when the plant has permission to product the 2rd generation ethanol from straw. In 2013, 80
tons of ethanol was produced from 300,000 tons over 400,000 tons straw in total.
 The plant produces in total 2,000- 2,300 m3 of biogas per hour or 80 million m3 per year.
 Reducing CO2 emission by 50,000 tons per year.
 Saving N and P emission into water course is reduced by 109 and 311 tons per year,
respectively.
1
Alan Lunde, 2013, Maabjerg BioEnergy prentation, Biochain Study tour, Maabjerg BioEnergy office, 24th Januar 2014
Quan Van Nguyen
nguyen@plen.ku.dk
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