Storage was used as a pretreatment to enhance the methanization performance of mesophilic anaerobic digestion of food waste. Food wastes were separately stored for 0, 1,2, 3, 4, 5, 7, and 12 days, and then fed into a ...Storage was used as a pretreatment to enhance the methanization performance of mesophilic anaerobic digestion of food waste. Food wastes were separately stored for 0, 1,2, 3, 4, 5, 7, and 12 days, and then fed into a methanogenic reactor for a biochemical methane potential（BMP） test lasting up to 60 days. Relative to the methane production of food waste stored for 0–1 day（285–308 m L/g-added volatile solids（VSadded））, that after2–4 days and after 5–12 days of storage increased to 418–530 and 618–696 m L/g-VSadded,respectively. The efficiency of hydrolysis and acidification of pre-stored food waste in the methanization reactors increased with storage time. The characteristics of stored waste suggest that methane production was not correlated with the total hydrolysis efficiency of organics in pre-stored food waste but was positively correlated with the storage time and acidification level of the waste. From the results, we recommend 5–7 days of storage of food waste in anaerobic digestion treatment plants.展开更多
Some rodents gather and store seeds.How many seeds they gather and how they treat those seeds is largely determined by seed traits such as mass,nutrient content,hardness of the seed coat,presence of secondary compound...Some rodents gather and store seeds.How many seeds they gather and how they treat those seeds is largely determined by seed traits such as mass,nutrient content,hardness of the seed coat,presence of secondary compounds,and germination schedule.Through their consumption and dispersal of seeds,rodents act as agents of natural selection on seed traits,and those traits influence how rodents forage.Many seeds that are scatter-hoarded by rodents are pilfered,or stolen,by other rodents,and seed traits also likely influence pilfering rates and seed fates of pilfered seeds.To clarify coevolutionary relationships between rodents and the plants that they disperse,one needs to understand the role of seed traits in rodent foraging decisions.We compared how the seeds of 4 species of plants that are dispersed by scatter-hoarding animals and that differ in value(singleleaf piñon pine,Pinus monophylla;desert peach,Prunus andersonii;antelope bitterbrush,Purshia tridentata;Utah juniper,Juniperus osteosperma)were pilfered and recached by rodents.One hundred artificial caches of the 4 seed species(25 per species)were prepared,and removal by rodents was monitored.Rodents pilfered high-value seeds more rapidly than the other seeds.Desert peach seeds,which contain toxic secondary compounds,were more frequently recached.Relatively low value seeds like Utah juniper and antelope bitterbrush were pil-fered more slowly and were sometimes left at cache sites,and seeds of the latter species were transported shorter distances to new cache sites.The background density of seeds also appeared to influence the relative value of seeds.展开更多
基金supported by the National Basic Research Program (973) of China (No. 2012CB719801)the National Natural Sceince Foundation of China (Nos. 51378375, 51178327+2 种基金 21177096)the Fundamental Research Funds for Central Universities (No. 0400219272)the Collaborative Innovation Center for Regional Environmental Quality
文摘Storage was used as a pretreatment to enhance the methanization performance of mesophilic anaerobic digestion of food waste. Food wastes were separately stored for 0, 1,2, 3, 4, 5, 7, and 12 days, and then fed into a methanogenic reactor for a biochemical methane potential（BMP） test lasting up to 60 days. Relative to the methane production of food waste stored for 0–1 day（285–308 m L/g-added volatile solids（VSadded））, that after2–4 days and after 5–12 days of storage increased to 418–530 and 618–696 m L/g-VSadded,respectively. The efficiency of hydrolysis and acidification of pre-stored food waste in the methanization reactors increased with storage time. The characteristics of stored waste suggest that methane production was not correlated with the total hydrolysis efficiency of organics in pre-stored food waste but was positively correlated with the storage time and acidification level of the waste. From the results, we recommend 5–7 days of storage of food waste in anaerobic digestion treatment plants.
文摘Some rodents gather and store seeds.How many seeds they gather and how they treat those seeds is largely determined by seed traits such as mass,nutrient content,hardness of the seed coat,presence of secondary compounds,and germination schedule.Through their consumption and dispersal of seeds,rodents act as agents of natural selection on seed traits,and those traits influence how rodents forage.Many seeds that are scatter-hoarded by rodents are pilfered,or stolen,by other rodents,and seed traits also likely influence pilfering rates and seed fates of pilfered seeds.To clarify coevolutionary relationships between rodents and the plants that they disperse,one needs to understand the role of seed traits in rodent foraging decisions.We compared how the seeds of 4 species of plants that are dispersed by scatter-hoarding animals and that differ in value(singleleaf piñon pine,Pinus monophylla;desert peach,Prunus andersonii;antelope bitterbrush,Purshia tridentata;Utah juniper,Juniperus osteosperma)were pilfered and recached by rodents.One hundred artificial caches of the 4 seed species(25 per species)were prepared,and removal by rodents was monitored.Rodents pilfered high-value seeds more rapidly than the other seeds.Desert peach seeds,which contain toxic secondary compounds,were more frequently recached.Relatively low value seeds like Utah juniper and antelope bitterbrush were pil-fered more slowly and were sometimes left at cache sites,and seeds of the latter species were transported shorter distances to new cache sites.The background density of seeds also appeared to influence the relative value of seeds.
