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The effects of lime mud from papermaking process (LMP) addition as buffer agent and inorganic nutrient on the anaerobic digestion stability of food waste (FW) were investigated under mesophilic conditions with the aim of avoiding volatile fatty acids accumulation, and inorganic elements deficiency. When LMP concentration ranged from 6.0 to 10g/L, the FW anaerobic digestion could maintain efficient and stable state. These advantages are attributed to the existence of Ca, Na, Mg, K, Fe, and alkaline substances that favor the methanogenic process. The highest CH4 yield of 272.8mL/g-VS was obtained at LMP and VS concentrations of 10.0 and 19.8g/L, respectively, with the corresponding lag-phase time of 3.84d and final pH of 8.4. The methanogens from residue digestates mainly consisted of Methanobrevibacter, coccus-type and sarcina-type methanogens with LMP addition compared to Methanobacteria in control. However, higher concentration of LMP inhibited methanogenic activities and methane production., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

In situ experiments and two lamb digestion trials were conducted to evaluate the effects of chemically treating recycled newsprint (NP). Treatment of NP with 2% HCl (percentage of NP DM) followed by autoclaving for 4 h was most efficacious and was used in an in vivo digestion trial with 25 ram and wether lambs in a randomized complete block design (RCB). On a DM basis treatment diets were: 1) control, 95% alfalfa hay (AH); 2) 75% AH, 20% HCl-treated NP (HCl-NP); 3) 55% AH, 40% HCl-NP; 4) 75% AH, 20% untreated NP; and 5) 55% AH, 40% untreated NP on a DM basis. Lambs fed Treatments 2 and 3 had ad libitum DMI (1,043 and 1,036 g/d, respectively) similar to the DMI of those fed the control treatment (1,024 g/d); however, lambs fed Treatments 4 and 5 had lower (P < .05) ad libitum DMI (578 and 426 g/d, respectively) than lambs fed Treatments 1, 2, and 3. Apparent DM digestibilities were lower (P < .05) by lambs consuming Treatments 2, 3, 4, and 5 (52.6, 44.5, 52.0, and 48.2%, respectively) than by those consuming Treatment 1 (60.7%). Apparent OM, CP, NDF, and ADF digestibilities followed trends similar to DM. In the second digestion trial, 15 ram and wether lambs were used in a RCB to compare Treatments 1, 2, and 3. For this second digestion study, NP was treated with 4% HCl (percentage of NP DM), autoclaved for 4 h, and diets were fed at 2% of BW. As in Trial 1, apparent nutrient digestibilities decreased (P < .05) with increasing amounts of HCl-NP. Our results suggest that HCl-NP can be fed to sheep at 40% of the diet without a decrease in DMI; however, apparent nutrient digestibility decreases with increasing levels of HCl-NP.