BIOFUEL
FAT RECOVERY, TYPE i-FAT
Turn fatty flotation sludge into biofuel
REVISION 2.0 - MAY 2016
FAT RECOVERY
Turn fatty flotation sludge into biofuel
FLOTATION SLUDGE IN THE FOOD MARKET
Industrial wastewaters with a high fat content are often treated by
dissolved air flotation (DAF) to remove fat and solids before secondary
(biological) treatment is applied. Typical wastewaters containing
high concentrations of oil and grease (O&G) include wastewaters of
slaughterhouses, processing plants (like bacon) and confectionary
plants. In general, a reduction of 45-70% total suspended solids
(TSS) and 50-80% O&G can be achieved by DAF. While fat is the
predominant dry matter of the sludge, this valuable resource is
currently not recovered.
However, if recovered, this fat may be applied for:
• Energy production on-site, for biofuel production
• Further processed as medium and long chain fatty acids
serving as building blocks for the chemical industry.
Fat recovery can be obtained by heating the dissolved air
flotation sludge, followed by separation into a liquid fat, a water and
a solids fraction. The wastewater after the fat recovery can be purified
to different standards: suitable for discharge to local sewage systems,
agricultural irrigation purposes, discharge to surface waters like rivers
and lakes or even suitable for re-use in parts of the process and/or
related parts of the integrated system.
CUSTOMER BENEFITS
A ROI based system dependant on the water, solids and fat
concentration in the flotation sludge with several benefits such as:
1. No flotation sludge disposal cost.
2. Use DAF as a smart integrated solution to recover fat.
3. Robust and effective separation of water and sludge.
4. Generate biofuel and steam from wastewater.
5. Valuable fertilizer / feed to digester.
6. Clean wastewater and pay less on trade effluent charges.
WHAT IS FLOTATION SLUDGE?
Prior to entering a secondary treatment-step such as a biological
treatment, wastewaters require primary treatment consisting of filter
and flotation techniques to reduce the solids and fat content in the
water.
Course solids can be filtered from the water by using the Nijhuis
patented NTF rotating filter or Nijhuis Aquarake. Fats passing through
the filter together with the water can be separated by the unique and
reliable Nijhuis flotation-systems which will generate flotation-sludge.
Flotation-sludge is a mixture of water, solids and (animal) fat.
Nijhuis Industries I www.nijhuisindustries.com
HOW TO SEPARATE FLOTATION SLUDGE?
HOW TO USE THE SEPARATED WATER, SOLIDS AND FAT?
Heating is the first step in the process where all the fat is liquefied
and the second and third step are to separate the solids and water
respectively. Separation techniques are required to guarantee a
thorough separation of all three phases and substantially increase
the yield of fat.
The separated water can be sent back to your wastewater treatment
plant, whereas the separated solids-proteins can be utilized as
fertilizer. The separated fat obtained can be used for various
technical purposes such as fuel for steam boilers or biofuel. The fat
is also a trade-commodity with high value.
“Nijhuis is not only providing customers with a solution for their wastewater but also
turning waste into a valuable end-product, creating value out of wastewater.”
Nijhuis Industries I www.nijhuisindustries.com
AN EXAMPLE OF THE NIJHUIS i-FAT
The flotation fat recovery system has been delivered to one of the bacon processing factories in
Ireland to turn their flotation fat into a resource recovery solution. The customer was looking for
a system to recover fat from their sludge. After installing the Nijhuis pre-treatment and biological
system, the customer designed, in close consultation with Nijhuis, a flotation fat recovery system
turning their fat into biofuel.
System configuration and solution
After the coarse solids are separated with a Nijhuis Aquarake filtration step the wastewater enters
a Nijhuis flotation fat recovery unit to separate the sludge from the wastewater, producing maximum of 30 m3/d sludge. The sludge is
heated in a heating tank before entering the solid separation stage. The separated fat and water are treated by a dewatering stage and the
recovered fat is stored in heated tanks.
Results
The installation recovers up to 6 m3 fat per day. Daily, 3 m3 fat is used to feed a steam boiler and supply the entire factory with energy.
The quality of the produced fat was also suitable for biodiesel production and an additional 3 m3 fat per day is sold for the production of
biodiesel. By calculating the CAPEX and OPEX for this full scale fat recovery system, it was determined that the return on investment was
less than 1.5 year.
Results of the Flotation Fat Recovery
System for a bacon company
Flotation sludge
flow
Capacity fat
recovery
Fat to steam
boiler
Biofuel
production
[m3/d]
30
[m3/d]
6
[m3/d]
3
[m3/d]
3
CONTACT
Contact us to evaluate your business case
E: [email protected]
T: +31 (0)314 74 90 00
Doetinchem I The Netherlands
Or contact your local sales & service center:
www.nijhuisindustries.com
Nijhuis Industries I www.nijhuisindustries.com