光照强度对丝状藻去除再生水中氮磷的影响

Effect of Light Intensity on Nitrogen and Phosphorus Removal from Reclaimed Water by Filamentous Algae

再生水中的N、P营养盐使再生水在回用过程中存在藻华暴发的风险,通过丝状藻去除再生水中的N、P营养盐,并将其转化为生物资源,可以有效降低再生水回用风险,实现资源化利用.光照强度会影响丝状藻的生长及藻细胞内的物质含量,从而影响藻类对再生水的脱氮除磷效果.为探究不同光照强度对丝状藻生长及其去除再生水中N、P的影响,以水绵、结节鞘藻、丝藻和转板藻4种丝状藻为研究对象,探究了不同光照强度(0、2000、6000、8000、10000 lx)下,4种丝状藻在实验室配制的再生水中的生长情况及再生水中N、P浓度的变化.结果表明:①光照强度为8000 lx时,水绵、结节鞘藻、丝藻和转板藻对TN的去除率最高,分别为48.33%、64.87%、49.74%、79.32%;除水绵、丝藻在低光照强度时TP的去除率较低外,其他试验组均能有效去除再生水中的TP,去除率均在90%以上.②水绵、结节鞘藻、丝藻的饱和光照强度为8000 lx,此时其生物质产量、蛋白质含量和脂质含量均最高,转板藻的饱和光照强度大于8000 lx,低于10000 lx.③再生水中培养的丝状藻,其体内蛋白质含量高于脂质含量.研究显示,转板藻具有更好地去除再生水中N、P营养盐的能力,并且具有更高的饱和光照强度.

In general,nutrients(nitrogen and phosphorus)in reclaimed water may cause harmful algal blooms in the process of reuse.Filamentous algae can convert nutrients in reclaimed water into biological resources such as protein and lipid,which can effectively reduce the incidence of harmful algal blooms in the process of reclaimed water reuse.Light intensity can affect the growth of filamentous algae and the content of the intracellular substances,thus affecting the removal of nitrogen and phosphorus in reclaimed water.To investigate the effects of different light intensity on the growth of filamentous algae and the removal efficiency of nitrogen and phosphorus from reclaimed water,four filamentous algae(Spirogyra sp.,Oedogonium nodulosum,Ulothrix sp.,and Mougeotia sp.)were selected.The filamentous algae were cultured in laboratory-formulated recycled water at different light intensities(0,2,000,6,000,8,000,10,000 lx),and the growth of filamentous algae and the changes of N and P content in the recycled water were monitored at different light intensities.When the light intensity was 8,000 lx,the results showed that the highest TN removal rates of Spirogyra sp.,Oedogonium nodulosum,Ulothrix sp.,and Mougeotia sp.were 48.33%,64.87%,49.74% and 79.32%,respectively.TP removal was low by Spirogyra sp.at light intensity of 2,000,6,000 lx and by Ulothrix sp.at 2,000 lx.The TP removal reached more than 90% under other conditions.The saturated light intensities for Spirogyra sp.,Oedogonium nodulosum,and Ulothrix sp.were all 8,000 lx,the biomass yield,protein content and lipid content were the highest,and the saturated light intensities for Mougeotia sp.were between 8,000 and 10,000 lx.The protein content of filamentous algae cultured in reclaimed water was higher than lipid.The study showed that the Mougeotia sp.was more suitable for the removal of N and P in reclaimed water.