Process evaluation of energy requirements for feed production using dairy wastewater for algal cultivation: Theoretical approach
Process evaluation of energy requirements for feed production using dairy wastewater for algal cultivation: Theoretical approach
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DOI：
10.1016/j.algal.2016.08.017
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发表时间：
2016-11
影响因子：
5.1
通讯作者：
Shahrzad Badvipour;Everett Eustance;M. Sommerfeld
中科院分区：
文献类型：
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作者：
Shahrzad Badvipour;Everett Eustance;M. Sommerfeld
乳制品生产是一种集约化的农业实践，引发了许多环境问题，包括有毒排放，对附近人类社区的潜在健康风险和水生生态系统的富营养化。这些环境影响可以通过使用排放物和溶解的营养物质（包括乳制品废水中的氮）来减少，以生产藻类生物质，与苜蓿相比，藻类生物质可以回收用于蛋白质含量更高的动物饲料。然而，能量需求是选择藻类生物质培养系统的主要标准。传统上，藻类已经在水道中培养以最小化能量输入，但水道与光生物反应器相比往往具有较低的面积生物质生产力。然而，更高的生产率可以通过利用重力提供减少的培养深度和温度控制策略的创新设计的增长来实现。动物饲料生产的可行性在跑道相比，重力饲料生产系统，以评估生产成本和直接能源需求。农业型重力式生产系统的估计耕作能耗为25 Wh m− 2d− 1，而跑道的能耗为15.4 Wh m− 2d − 1。然而，这些系统可以显着增加面积生物质生产率，将生物质生产所需的能量从2.01 kWh kg-1减少到1.41 kWh kg-1。当沉降与离心结合以实现25%的固体含量时，用于生物质培养和收获的能量的总成本估计在重力进料系统和滚道中分别为每吨176美元和256美元。这可以与仅在重力进料系统和滚道中使用离心处理时的每吨生物质分别为334美元和1407美元相比。
Dairy production is an intensive agricultural practice that elicits many environmental concerns including noxious emissions, potential health risks to nearby human communities and eutrophication of aquatic ecosystems. These environmental impacts can be reduced by using the emissions and dissolved nutrients including nitrogen available in dairy wastewaters to produce algal biomass, which can be recycled for animal feed with higher protein content compared to alfalfa. However, energy demand is a major criterion for selecting an algal biomass cultivation system. Traditionally algae have been cultivated in raceways to minimize energy input, but raceways tend to have lower areal biomass productivity compared to photobioreactors. However, higher productivity may be achievable through growth in innovative designs utilizing gravity to provide reduced cultivation depths and temperature control strategies. The feasibility of animal feed production in raceways is compared to gravity fed production systems for evaluating production cost and direct energy demand. Agricultural style gravity fed production systems have an estimated cultivation energy consumption of 25 Wh m− 2d− 1compared to raceways at 15.4 Wh m− 2d− 1. However, these systems can significantly increase areal biomass productivities reducing the energy required for biomass production from 2.01 kWh kg− 1to 1.41 kWh kg− 1. Total cost of energy for biomass cultivation and harvesting, when sedimentation is combined with centrifugation to achieve 25% solid content, is estimated to be $176 and $256 per mton in gravity fed systems and raceways, respectively. This can be compared to $334 and $1407 per mton of biomass when only using centrifugation for processing in gravity fed systems and raceways, respectively.