Sponge iron (SI) is a promising material for nitrogen removal from wastewater. This study reveals the potential functions and mechanisms of SI-mediated multiple metabolic processes in the nitrogen removal of Anammox. The results showed that although the SI application prolonged the start-up time of the reactor, achieved efficient and stable nitrogen removal after a successful start-up. The total nitrogen removal efficiency of the SI-Anammox system (92.62%) was 13.30% higher than that of R0 without SI (79.32%). The increase in nitrogen removal performance was accompanied by an increase in SAA and EPS content. Further microbial analysis showed significant enrichment of functional microorganisms, such as Candidatus_Brocadia, Nitrosomonas, Ellin6067, and Nitrospira. Multi-omics evidence suggests that efficient nitrogen removal is ultimately attributable to the enhancement of the specific key Fe- and N-functional genes in Anammox.

厌氧氨氧化脱氮是目前的热点研究方向,受到广泛关注.然而,厌氧氨氧化菌工艺有自身的局限性,厌氧氨氧化菌的快速富集受到很多因素的制约,影响厌氧氨氧化工艺的应用与推广.对此,根据前人的研究成果,本文针对厌氧氨氧化的局限性,对温度、pH、溶解氧、有机物、底物浓度、盐度等影响因素进行了详细综述,希望对后续研究提供一定的借鉴与帮助.

以经济欠发达黄土高原沟壑区典型县域(秦安县)农村生活污水处理规划为例,结合实际情况提出了农村生活污水治理原则及模式,最后探讨了农村生活污水治理的重点问题.农村生活污水治理应遵循改善环境迫切需要和聚集性大村优先的原则;农村生活污水治理分为集中治理和资源化利用治理,其中集中治理包括城镇污水处理厂集中处理和村级集中污水处理站的处理,资源化利用治理包括水冲式厕所资源化处理和卫生旱厕资源化处理.修建村级集中污水处理站时每户村民平均支管长度约11.35m,支干管长度约3.79m,户均投资要大于修建乡镇污水处理厂;资源化利用模式投资最省.规划结果表明集中处理与资源化利用模式占比分别约为30％和70％,投资总额相比秦安县财政状况,负担很重.

The application of anaerobic ammonium oxidation (Anammox) technology in low-strength wastewater treatment still faces difficult in-situ start-ups and unstable operations. Sponge-iron sludge (R1) was used as a novel inoculum to provide a promising solution. Conventional activated sludge (R0) was used as the control. However, little is known about the feasibility and performance during the start-up and operation of Anammox combined with biological iron and iron bacteria in an iron sludge system. Anammox was successfully started both in R1 (87 days) and R0 (89 days) with a low-strength influent (with a nitrogen loading rate (NLR) of 43.64 +/- 0.41 g N/(m(3).d)). During long-term operation, the R0 nevertheless produced higher nitrates (9.7 +/- 0.1 mg/L) than expected. In contrast, R1 presented no excess nitrate production (2.1 +/- 0.06 mg/L). The total inorganic nitrogen (TIN) removal efficiency increased from 78.2 +/- 7.1% in R0 to 86.1 +/- 4.3% in R1. The iron sludge in R1 was divided equally into three parts and three different nitrogen-feeding methods were used over the 34 days of operation, as follows: first using a mixture of ammonium (27.15 +/- 1.0 mg/L) and nitrite (32.7 +/- 1.7 mg/L), then only ammonium (27.15 +/- 1.0 mg/L) and lastly only nitrite (32.7 +/- 1.7 mg/L) as the influent. R1 was a coupled system composed of Anammox, Feammox, and NOx--dependent Fe(II) oxidation (NDFO). The contribution of Feammox and NDFO to TIN removal was 27.1 +/- 1.2% and 31.9 +/- 0.7%. However, Anammox was the primary nitrogen transformation pathway. X-ray diffraction (XRD) analysis shows that iron hydroxide (Fe(OH)(3)) and iron oxide hydroxide (FeOOH) were generated in R1. The produced Fe(OH)(3) and FeOOH were capable of participating in Feammox and formed a Fe(II)/Fe(III) cycle which further removed nitrogen. Therefore, a highly stable and impressive nitrogen removal performance was demonstrated in the iron sludge Anammox system under the cooperation of biological iron and iron bacteria. The study considered the enrichment of norank_c_OM190, Desulfuromonas, and Thiobacillus and their contribution to the Anammox, Feammox, and NDFO processes, respectively. This study provides a new perspective for the start-up and stable operation of low-strength wastewater Anammox engineering applications.