| Popis: |
Concentrated animal feeding operations (CAFO) using water-flush systems creates excessive manure slurriescontaining high solids and phosphorus (P). Using pre-screened slurry (1.0 mm) in Part I, optimum combinationconcentrations for dewatering for two coagulants (AlCl3 and FeCl3) and one flocculant (255G-PAM) were identified. In afollow-up separate experiment in Part II, the identified optimum concentrations were evaluated for their total solids (TS) andtotal P (TP) removal capability using the same type of pre-screened slurry (1.0 mm) in combination with a 0.5-mm staticscreen. In Part I, aluminum (Al) and iron (Fe) alone increased dewatering 70 to 80 times compared to the control, decreasedfiltrate pH as their respective concentrations increased, and decreased filtrate total dissolved P (TDP). Coagulants combinedwith 255G-PAM enhanced the dewatering capabilities 1.5 to 1.7 times at lower coagulant concentrations. Interactionbetween the coagulants and 255G-PAM dewatered the slurry and removed P more efficiently than the control or coagulantsalone. In Part II, the TP removed was directly correlated to the quantity of screened solids removed (R2 = 0.92). Treatments(on screen) removed 3 to 8 times more TS and 6 to 25 times more TP than the control, with mean recoveries of 100% and 76%for TS and TP, respectively. Interaction between the coagulants and 255G-PAM removed TS and TP more efficiently comparedto the control and coagulants alone. Treatments reduced the amount of TDP in the filtrate 87 to 182 times, demonstrating thistechnology has potential for improving manure management provided chemical treatment can be combined with solidseparation on a practical and commercial scale. |
