REVISION 2.0 - MAY 2016

FAT RECOVERY, TYPE i-FATTurn fatty flotation sludge into biofuel

BIOFUEL

FLOTATION SLUDGE IN THE FOOD MARKETIndustrial 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.

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

FAT RECOVERYTurn fatty flotation sludge into biofuel

CUSTOMER BENEFITSA 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.

HOW TO SEPARATE FLOTATION SLUDGE?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.

HOW TO USE THE SEPARATED WATER, SOLIDS AND 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 Industries I www.nijhuisindustries.com

“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.”

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 solutionAfter 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

[m3/d] 30

Capacity fat recovery

[m3/d] 6

Fat to steam boiler

[m3/d] 3

Biofuel production

[m3/d] 3

Nijhuis Industries I www.nijhuisindustries.com

AN EXAMPLE OF THE NIJHUIS i-FAT

CONTACT

Contact us to evaluate your business case

E: info@nijhuisindustries.comT: +31 (0)314 74 90 00

Doetinchem I The Netherlands

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