Secondary Protein Nutrients (SPN) are the DAF skimmings that result from the poultry wastewater treatment process. These skimmings are high in valuable fats, oils and grease from poultry processing. Like other processing by-products (such as trimmings, blood, bones and feathers), SPN can be recycled by rendering plants, and used for animal feed, biofuels, lubricants and other products. When processing plants sell DAF skimmings as SPN to renderers, not only do they realize some revenue, but they avoid the alternative very expensive disposal cost. DAF sludge that cannot be rendered is usually disposed of through land application or, increasingly, landfill disposal. As with other biosolids and sewage waste, sludge disposal is very costly and suitable land for application is becoming more scarce. Consequently, poultry processors are much better off selling SPN to renderers rather than paying for disposal through land application.
However, plants that use FeCl or other metal salts in their wastewater treatment often are unable to sell DAF skimmings to renderers as SPN. This is due to potential toxicity and the increased risk of combustion in the heat processing in the rendering operation. Plants using FeCl thus are forced to use land application for disposal of DAF sludge. Often multiple DAFs are used so that some skimmings can be generated and sold as SPN prior to the application of FeCl in a secondary DAF.
Nclear partnered with Fieldale Farms to extensively test TPXTM at its poultry kill plant in Cornelia, Georgia in a series of 72-hour sidestream tests. Nclear’s mobile pilot system included a custom-built 10 gallon per minute (gpm) DAF with multiple chemical injection points and floc tubes, polymer and coagulant feed tanks, acidulation system, equalization (EQ) tanks and the TPXTM slurry system.
The pilot system allows Nclear to effectively simulate the plant’s entire wastewater processing plant. EQ tanks are sized to simulate the retention time and aeration characteristics of the plant’s flow equalization basin(s), as well as any equalization tanks or ponds at the effluent end of the wastewater process.
Pilot Evaluations were conducted around the clock for 72-96 hours, with daily composite testing of both direct DAF effluent and aerated EQ tank effluent. Nclear’s portable lab provided real-time analysis of pH, TP, Ortho P (OP), and COD. Composite samples were also sent to both Fieldale’s corporate lab as well as a third-party lab for independent verification of results and additional analyses of BOD, TKN and TSS. Results were compared with Fieldale’s own wastewater effluent and were used to evaluate full scale treatment costs.
The data above shows that while there is a significant increase in chemical costs, as TPXTM (an engineered synthetic mineral) is substituted for commodity chemicals (FeCl and quicklime), this cost is more than offset by the savings in land application, the SPN revenue increase, and the total reduction in transport costs due to less total DAF solids. But the significant savings is only part of the benefit. TPXTM is more environmentally friendly than metal salts, as it maximizes the plant’s ability to recycle biproducts and eliminate land application practices (or even landfill disposal). It also provides operating benefits by eliminating the need to operate multiple DAF’s in sequence, reducing total solids production, and eliminating manual tasks such as lime mixing.
Fieldale Farms is moving forward with full scale implementation of Nclear’s TPXTM solution in conjunction with other wastewater plant upgrades. The substantial cost savings, operational benefits and, most importantly, the advancement of sustainability objectives make this an ideal solution for Fieldale Farms’ wastewater processing.
“The displacement of FeCl with Nclear’s non-toxic TPXTM nanocrystal will enable all of our processing facilities to achieve our corporate sustainability goals while also improving our fiscal bottom line. This truly is a win-win for Fieldale Farms and we are excited to be moving forward with such cutting-edge technology.” Charles Hardeman, Environmental Manager, Fieldale Farms