生物沸石人工湿地处理分散养猪冲洗水性能

以构建的三级生物沸石人工湿地处理分散养猪冲洗水厌氧出水,考察了湿地的运行性能、污染物随时间变化以及生物沸石层ORP分布情况.结果表明,三级生物沸石人工湿地可高效地去除分散养猪冲洗水厌氧出水的COD、N和P,且耐NH_4~+-N冲击负荷.湿地水力负荷为0.047 m~3·(m~2·d)~(-1)时,COD、NH_4~+-N和TN(平均质量浓度分别为477.7、155.3和176.4mg·L~(-1))主要在湿地一区被去除,平均去除率分别为80.6%、55.3%和58.1%.生物沸石强化硝化作用明显,硝化产物主要为硝酸盐,湿地一区、二区和三区的NO_3~--N产生质量浓度分别为85.85、91.06和82.41 mg·L~(-1),一区沸石层产生的硝酸盐可被其下部砖渣层微生物利用水中剩余有机物为底物,通过反硝化途径去除.TP主要靠砖渣吸附去除,微生物的作用相对较小.三级湿地沸石层复氧效果均较好,大部分ORP值都保持在400 m V以上.

Performance of Bio-zeolite Constructed Wetland in Dispersed Swine Wastewater Treatment

The anaerobically digested effluent of the dispersed swine wastewater was treated by a three-stage bio-zeolite constructed wetland, and the performance of the wetland, the variation of pollutants concentration in effluent and ORP distribution in the bio-zeolite layer were studied. The results showed that COD, N and P in the digested effluent could be efficiently removed by the wetland, and the wetland also had resistance to ammonia impact load. When the hydraulic loading rate was 0.047 m³·(m²·d)^-1, COD, NH₄⁺-N and TN (the average mass concentrations in inflow were 477.7, 155.3 and 176.4 mg·L^-1) were mainly removed in the district 1 of the wetland, and the average removal rates were 80.6%, 55.3% and 58.1%, respectively. There was obvious enhancement of nitrification in the bio-zeolite, and the major nitrification product was nitrate. The mass concentrations of NO₃^--N in the district 1, district 2 and district 3 of the wetland were 85.85, 91.06 and 82.41 mg·L^-1, respectively. The nitrate produced in bio-zeolite layer of the district 1 could be denitrified by microorganisms in the slag brick layer using the residual organic substances in water as the substrate. TP was mainly removed by adsorption in the slag brick layer, and the role of microbe assimilation was relatively small. The reaeration of the bio-zeolite layer in the three-stage wetland was good. Most of the ORP values remained over 400 mV in the bio-zeolite layer.