人工湿地联合塘内设施调控生产性虾塘水环境的效果与技术

The effect and application of treatment for wastewater of productive shrimp aquaculture by constructed wetlands combined with pond facilities

研究了由表面流与水平潜流组成的复合人工湿地联合使用塘内曝气增氧机与人工净化网调控生产性淡水对虾养殖塘水环境的效果与技术。养殖中后期(约60 d后),湿地以1.65 m/d水力负荷,3次循环处理虾塘废水,有效调控虾塘水质,确保养殖成功。结果表明湿地对废水中有害物质均可程度不等地去除,蓝绿藻得以控制,出口水NO2-N与BOD5分别为极显著(P<0.01)与显著(P<0.05)去除,去除率与去除速率分别为72.6%,0.467 g/(m2.d)与29.7%,2.651 g/(m2 d),3PO 4-P为41.7%,0.022 g/(m2 d),TN为26.1%,2.619 g/(m2 d),CODMn为15.9%,3.738 g/(m2 d),NO3-N去除率仅3.6%,但去除速率较高[0.462 g/(m2 d)]。湿地静止4 d期间,废水中NO2-N与NO3-N去除率达96.8%与93.3%,均极显著去除(P<0.01)。养殖周期试验塘水化学指标均维持在虾安全生长范围内,收获虾8.81 g,9.36 cm;对照塘因爆发蓝绿藻仅养殖60 d,收获虾3.06 g,6.54 cm。试验表明,在不用药、不换水条件下,联合塘内设施,人工湿地以较高水力负荷与低频率运转可有效调控虾塘水质,确保养殖成功。

Wastewater treatment technologies with constructed wetlands and pond facilities for freshwater Litopenaeus vannamei culture were conducted and the effects were measured.The wetlands consist of free water surface（FWS） and subsurface horizontal flow（SF） wetlands.Ponds facilities contain aerators and artificial water purifying nets.During the middle and late culture period（about 60 d later）,shrimp ponds’ wastewater was recirculated three times through the wetlands under hydraulic loading rate（HLR） of 1.65 m/d which effectively improved water quality in shrimp ponds and ensured a good harvest.At the same time,the outbreak of blue-green algae was controlled.2 NO-N and BOD 5 at outlet were significantly removed at different levels（P〈0.01 and P〈0.05）.The removal percentage and removal rates were 72.6%,0.467 g/m 2.d and 29.7%,2.651 g/（m2·d）.The removal percentage and removal rates of 3 4 PO-P,TN and COD Mn were 41.7%,0.022 g/（m2·d）,26.1%,2.619 g/（m 2 d） and 15.9%,3.738 g/（m2·d） respectively.The removal percentage of 3 NO-N was only 3.6% but the removal rate was as high as 0.462 g/（m2·d）.2 NO-N and 3 NO-N were both significantly（P〈0.01） reduced by 96.8% and 93.3% when effluents remained in the macrophytes unit for 4 d.The water chemical parameters were all maintained within a safe range during the culture period.The harvested shrimp in experimental pond had the mean body weight of 8.81 g and length of 9.36 cm.While the culture in control group had to terminate on the 60th day due to an outbreak of shrimp disease caused by microcystin and the harvested shrimp was only 3.06 g and 6.54 cm each.The results indicated that low frequency operation of the constructed wetlands under a higher HLR combined with pond facilities could effectively control water quality in shrimp pond under the conditions of no water exchange and no medicine use and then ensured a good harvest.