Pig farming generates highly polluted wastewater that requires effective treatment to minimize environmental damage. Microalgae can recover nutrients from piggery wastewater (PWW), but excessive nutrient and turbidity levels inhibit their growth. Solar photo-Fenton (PF) offer a sustainable and cost-effective pretreatment to allow microalgal growth for further PWW treatment. This study optimized the concentrations of PF reagents to minimise water and nutrient inputs while maintaining microalgae-based treatment efficiency. PF trials were conducted in pilot-scale raceway ponds under solar radiation, testing different concentrations of FeSO4 (4.48 and 8.95 mM) and H2O2 (77, 154, and 309 mM). Following PF, Tetradesmus obliquus was used in a biological treatment of PWW to recover the remaining nutrients. PF achieved high removal efficiencies for turbidity (97.6–99.5 %), total organic carbon (59.2–77.1 %), and chemical oxygen demand (83.8–94.7 %), but ammonium was not significantly removed. Phosphorus was almost completely removed through iron precipitation during neutralisation. Lowering the H2O2 concentration from 309 to 77 mM did not compromise removal efficiency but reducing FeSO4 below 8.95 mM negatively affected the process. Consequently, 8.95 mM FeSO4 and 77 mM H2O2 were selected for microalgae production. The pretreated PWW could be recycled at least once for microalgal production, without nutrient supplementation, improving biomass productivity and PWW treatment, especially targeting ammonium. Phosphorus supplementation, however, did not significantly boost biomass productivity or treatment efficiency. Moreover, the iron sludge generated from PF pretreatment contained enough NPK to be repurposed as an organic fertilizer boosting sustainable agricultural practices. These findings encourage further investigation of this emerging combined technology towards wastewater treatment at large-scale.

中文翻译：

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通过太阳能光芬顿结合微藻生产处理猪场废水


养猪业会产生高度污染的废水，需要有效处理以尽量减少对环境的破坏。微藻可以从猪舍废水 （PWW） 中回收营养物质，但过高的营养物质和浊度水平会抑制它们的生长。太阳能光芬顿 （PF） 提供可持续且具有成本效益的预处理，以允许微藻生长以进行进一步的 PWW 处理。本研究优化了 PF 试剂的浓度，以最大限度地减少水和营养物质的输入，同时保持基于微藻的处理效率。PF 试验在太阳辐射下的中试规模水道池塘中进行，测试了不同浓度的 FeSO4 （4.48 和 8.95 mM） 和 H2O2 （77、154 和 309 mM）。在 PF 之后，Tetradesmus obliquus 用于 PWW 的生物处理以回收剩余的营养物质。PF 对浊度 （97.6-99.5 %）、总有机碳 （59.2-77.1 %） 和化学需氧量 （83.8-94.7 %） 实现了很高的去除效率，但铵没有被显著去除。在中和过程中，磷几乎通过铁沉淀完全去除。将 H 2 O 2 浓度从 309 降低到 77 mM 不会影响去除效率，但将 FeSO4 降低到 8.95 mM 以下会对该过程产生负面影响。因此，选择 8.95 mM FeSO4 和 77 mM H2O2 用于微藻生产预处理的 PWW 可以至少回收一次用于微藻生产，无需补充营养，提高生物质生产力和 PWW 处理，尤其是针对铵。然而，磷的补充并没有显著提高生物质的生产力或处理效率。此外，PF 预处理产生的铁污泥含有足够的 NPK，可以重新用作有机肥料，促进可持续农业实践。 这些发现鼓励进一步研究这种新兴的联合技术，以实现大规模废水处理。