Abstract:

A wood-chip-framework soil infiltrator (WFSI) with slow-release of carbon source was constructed and used to treat an anaerobically digested swine wastewater characterized with high NH₄⁺-N and low C/N ratio. Pollutant removal efficiency of the WFSI was investigated under various influent concentration and varying surface hydraulic load (SHL). Under SHL of 0.2 m³·m^-2·d^-1, influent averaged COD and NH₄⁺-N increased from 152 and 175.5 mg·L^-1 to 421 and 788.7 mg·L^-1, respectively. The resultant COD, NH₄⁺-N and TN removal by the system was 52.3% to 61.2%, 84.2% to 61.5% and 28.6% to 33.5%, respectively. Meanwhile, NH₄⁺-N and TN removal loading reached 75.5 and 41.7 g·m^-3·d^-1, respectively. Though SHL was as high as 0.32 m³·m^-2·d^-1, the system still performed but its efficiency was remarkably influenced. When influent COD and NH₄⁺-N was around 265 and 465 mg·L^-1, COD, NH₄⁺-N and TN removal was about 56.5%, 53.3% and 20.9%, respectively. The wood carrier observably worked as a slow-release carbon source, and protected the ammonia oxidizing bacteria from free ammonia toxicity due to the concentration gradient of NH₄⁺-N in the adhesive layers.

Key words: swine wastewater, anaerobically digested liquor, waste treatment, packed bed, permeation, nitrogen removal

摘要：

为处理高氨氮、低C/N比的养猪废水厌氧消化液, 构建了具有缓释碳源特性的木质框架土壤渗滤系统(WFSI), 并通过运行测试了进水浓度和表面水力负荷(SHL)对系统处理效能的影响。在SHL为0.2 m³·m^-2·d^-1条件下, 当进水COD和NH₄⁺-N平均浓度分别从152和175.5 mg·L^-1提高到421和788.7 mg·L^-1时, 系统对COD的去除率从52.3%提高到61.2%, NH₄⁺-N去除率从84.2%下降到61.5%, TN去除率从28.6%提高到了33.5%, NH₄⁺-N和TN去除负荷分别达到了75.5和41.7 g·m^-3·d^-1。当SHL提高为0.32 m³·m^-2·d^-1时, 系统仍能维持运行, 但处理效能受到显著影响。在进水COD 和NH₄⁺-N分别为265和465 mg·L^-1左右时, COD、NH₄⁺-N及TN的去除率分别平均为56.5%、53.3%和20.9%。木质填料及其附着层形成的NH₄⁺-N浓度梯度, 可使系统承受较高的SHL的同时获得缓释碳源, 并保护氨氧化细菌免受自由氨毒性。

关键词: 养猪废水, 厌氧消化液, 废物处理, 填充床, 渗透, 脱氮