Universidad del Valle, Cali, Colombia.
Water Sci Technol. 2012;66(9):1930-40. doi: 10.2166/wst.2012.396.
Greenhouse gas (GHG) emissions (CO(2), CH(4)) from pilot-scale algal and duckweed-based ponds (ABP and DBP) were measured using the static chamber methodology. Daylight and nocturnal variations of GHG and wastewater characteristics (e.g. chemical oxygen demand (COD), pH) were determined via sampling campaigns during midday (12:30-15:30) and midnight (00:30-03:30) periods. The results showed that under daylight conditions in ABP median emissions were -232 mg CO(2) m(-2) d(-1) and 9.9 mg CH(4) m(-2) d(-1), and in DBP median emissions were -1,654.5 mg CO(2) m(-2) d(-1) and 71.4 mg CH(4) m(-2) d(-1), respectively. During nocturnal conditions ABP median emissions were 3,949.9 mg CO(2) m(-2) d(-1), 12.7 mg CH(4) m(-2) d(-1), and DBP median emissions were 5,116 mg CO(2) m(-2) d(-1), 195.2 mg CH(4) m(-2) d(-1), respectively. Once data measured during daylight were averaged together with nocturnal data the median emissions for ABP were 1,566.8 mg CO(2) m(-2) d(-1) and 72.1 mg CH(4) m(-2) d(-1), whilst for DBP they were 3,016.9 mg CO(2) m(-2) d(-) and 178.9 mg CH(4) m(-2) d(-1), respectively. These figures suggest that there were significant differences between CO(2) emissions measured during daylight and nocturnal periods (p < 0.05). This shows a sink-like behaviour for both ABP and DBP in the presence of solar light, which indicates the influence of photosynthesis in CO(2) emissions. On the other hand, the fluxes of CH(4) indicated that DBP and ABP behave as net sources of CH(4) during day and night, although higher emissions were observed from DBP. Overall, according to the compound average (daylight and nocturnal emissions) both ABP and DBP systems might be considered as net sources of GHG.
采用静态箱法测定了中试规模藻类和浮萍池塘（ABP 和 DBP）的温室气体（GHG）排放（CO2、CH4）。通过在中午（12:30-15:30）和午夜（00:30-03:30）期间进行采样活动，确定了 GHG 和废水特性（例如化学需氧量（COD）、pH 值）的日变化和夜变化。结果表明，在 ABP 白天条件下，中值排放量为-232 mg CO2 m(-2) d(-1)和 9.9 mg CH4 m(-2) d(-1)，在 DBP 中值排放量为-1654.5 mg CO2 m(-2) d(-1)和 71.4 mg CH4 m(-2) d(-1)。在夜间条件下，ABP 中值排放量为 3949.9 mg CO2 m(-2) d(-1)、12.7 mg CH4 m(-2) d(-1)，DBP 中值排放量为 5116 mg CO2 m(-2) d(-1)、195.2 mg CH4 m(-2) d(-1)。将白天测量的数据与夜间数据平均后，ABP 的中值排放量为 1566.8 mg CO2 m(-2) d(-1)和 72.1 mg CH4 m(-2) d(-1)，而 DBP 的中值排放量为 3016.9 mg CO2 m(-2) d(-1)和 178.9 mg CH4 m(-2) d(-1)。这些数字表明，白天和夜间测量的 CO2 排放量之间存在显著差异（p < 0.05）。这表明 ABP 和 DBP 在存在太阳光的情况下表现出汇的行为，这表明光合作用对 CO2 排放的影响。另一方面，CH4 的通量表明，DBP 和 ABP 在白天和黑夜都是 CH4 的净源，尽管 DBP 的排放量更高。总体而言，根据化合物平均值（白天和夜间的排放量），ABP 和 DBP 系统都可能被视为 GHG 的净源。
