固定化微绿球藻去除NH_4^+-N、PO_4^(3-)-P效果的研究

STUDY ON REMOVAL RATE OF NH_4^+-N AND PO_4^(3-)-P BY IMMOBILIZED NANNOCHLOROPSIS OCULATA

为了探究固定化微绿球藻(Nannochloropsis oculata)去除污水中NH_4^+-N、PO_4^(3-)-P的效果,采用海藻酸钠固定化包埋技术进行实验。开展了固定化藻球大小、藻细胞包埋密度、藻球投放质量及充气培养条件对NH_4^+-N、PO_4^(3-)-P去除效果的单因子试验研究。结果表明,固定化藻球大小、藻细胞包埋密度、藻球投放质量和充气培养条件对NH_4^+-N、PO_4^(3-)-P的去除效果影响显著(P<0.05)。藻球直径3.5 mm时生长速率(K)值最大(0.332±0.002),同时NH_4^+-N、PO_4^(3-)-P去除率效果最佳,分别为(75.08±3.83)%和(80.80±3.81)%;藻细胞包埋密度100×10~4 cells/ball时K值最大(0.330±0.033),而NH_4^+-N、PO_4^(3-)-P去除率则以藻细胞包埋密度300×10~4 cells/ball组为佳,分别达(87.20±0.43)%和(82.58±1.72)%,但考虑单位藻细胞去除率,包埋密度以100×10~4 cells/ball为宜;随着藻球用量的增加K值下降,10g/L组K值最大(0.301±0.02)、50 g/L组K值最小(0.193±0.01),投放量30和50 g/L时NH_4^+-N去除率较高分别为(84.12±0.78)%和(84.63±0.45)%,30 g/L组PO_4^(3-)-P去除率最高达(77.13±1.43)%。综合考虑,藻球投放量选用30g/L为宜;充气条件培养K值、NH_4^+-N和PO_4^(3-)-P去除率显著(P<0.05)高于不充气,K值分别为(0.306±0.006)和(0.177±0.010);NH_4^+-N去除率分别为(85.93±0.45)%和(49.32±0.45)%;PO_4^(3-)-P去除率分别为(66.66±5.00)%和(46.29±2.12)%。研究优化了微绿球藻固定化条件:固定化微绿球藻应进行充气培养,藻球规格3.5 mm、藻细胞包埋密度100×10~4 cells/ball、藻球投放量30g/L。

Microalgae Nannochloropsis oculata, immobilized with sodium alginate, was used to explore its removal efficiency of NH4^＋-N and PO3-^4-P from artificial sewage water. Algae ball size, cell densities, dosages of algae balls, and aeration cultured were applied in the single-factor. The results showed that all these conditions significant impact the removal of of NH4^＋-N and PO3-^4-P. The growth rate of K value achieved the highest value （0.332±0.002） when the diameter was 3.5 mm; the removal rate of NH4^＋-N and PO3-^4-P were the highest one at the diameter was 3.5 mm, which were （75.08±3.83）% and （80.80±3.81）%, respectively. The maximum of the growth K values was （0.330±0.033） with the density of 100×104 cells/ball. The highest NH4^＋-N and PO3-^4-P removal rate were （87.20±0.43）% and （82.58±1.72）%, respectively, at the group of 300×104 cells/ball; however, 100×104 cells/ball was the optimal algal cell density based on unit algal cells removal ratio of NH4^＋-N and PO3-^4-P. The increased algae balls dosages decreased the growth rate of K values. 10 g/L group had the maximum K values （0.301±0.02） and 50 g/L had the minimum K values （0.193±0.01）. The removal rates of NH4^＋-N were （84.12±0.78）% and （84.63±0.45）% when the dosage was 30 g/L and 50 g/L, respectively. 30 g/L group had the highest PO3-^4-P removal rate （77.13±1.43）%. Combined analyses revealed that 30 g/L was optimum for the dosages of algae balls. The K value, the removal of NH4^＋-N and PO3-^4-P were significantly （P〈0.05） higher with aeration than non-aerated; K values were （0.306±0.006） and （0.177±0.010）, respectively; NH4^＋-N removal rates were （85.93±0.45）% and （49.32±0.45）%, respectively; PO3-^4-P removal rates were （66.66±5.00）% and （46.29±2.12）%, respectively. This study optimized the conditions of immobilized microalgae Nannochloropsis oculata：immobilized Nannochloropsis oculata should be aerated cultures; algae ball size was 3.5 mm; the algal cell density was 100×104 cells/ball; and the dosage of algae balls was 30 g/L.