Effect of Fe2+ and Fe0 Applied Photo‐Fenton Processes on Sludge Disintegration

The disintegration of waste active sludge was investigated by photo‐Fenton processes. A batch study was conducted to evaluate parameters, such as Fe²⁺ and Fe⁰ ions and H₂O₂, governing the activated sludge integration by the photo‐Fenton process. Under optimum conditions, the concentration of soluble chemical oxygen demand (SCOD) with the classical Fenton process (CFP) increased very rapidly in the first five minutes due to the sufficient presence of reaction components in the medium, and then the rate of increase declined. In the modified Fenton process (FTP), the SCOD concentration increased more slowly as metallic iron powder must first be dissolved. The photo‐Fenton process proved to be a feasible and efficient process for the disintegration of waste sludge.     

PBAT‒PLA膜袋受控需氧堆肥条件下的降解研究

目的 通过对广泛使用的PBAT–PLA生物降解膜袋在受控需氧堆肥条件下的降解机制研究，为生物降解塑料的大规模推广提供重要理论基础。方法 根据GB/T 19277.1—2011，在(58±2)℃需氧条件下，对PBAT–PLA膜袋进行为期160 d的生物降解测试(即工业堆肥)，并以常见的可降解材料微晶纤维素作为参比样品。对降解前后的材料进行红外、扫描电镜、能谱分析，并结合其所在堆肥样本的脂肪酶活性，从多角度探寻降解机制。结果 PBAT–PLA膜袋与微晶纤维素所在的堆肥脂肪酶活性都达到空白堆肥的3倍以上。红外显示由微晶纤维素水分子吸附、糖环打开、基团氧化形成的吸收峰加强，PBAT–PLA膜袋中的酯键峰明显减弱;扫描电镜发现降解的PBAT–PLA膜袋表面覆盖了微生物膜;能谱分析发现，碳元素大幅减少，氧元素增加。结论 微生物在PBAT–PLA膜袋表面生长形成生物膜，分泌大量脂肪酶，水解PBAT–PLA的酯键，使聚合物降解为不同链长的中间体或小分子，同时伴随着氧化，随后被作为碳源，在相关微生物体内被代谢利用，形成最终产物。     

Nymphoides peltatum as a novel feedstock for biomethane production via anaerobic co-digestion with waste sludge

Nymphoides peltatum (NP) is exploited as a novel feedstock for biomethane production via anaerobic co-digestion with waste sludge (WS). Batch experiments are conducted under mesophilic condition at NP/WS of 1/3, 2/2, 3/1, 0/4 and 4/0 based on volatile solids (VS). Prior to anaerobic digestion (AD), NP undergoes only natural drying and grinding. The maximum net cumulative methane yield (265.16 mL CH₄·g VS_added^?1) and the highest gross VS removal rate (56.12%) are obtained at NP/WS of 1/3. The kinetic analysis by the modified Gompertz model fit hinted that 28 days is adequate for methane recovery and co-digestion significantly accelerates the digestion rate. Synergetic effect is corroborated to exist in co-digestion due to amiable conditions in term of total ammonia nitrogen, free ammonia, pH, volatile fatty acids and total alkalinity. High-throughput 16S rRNA pyrosequencing reveals that Bacteroidetes, Firmicutes, Methanosarcina and Methanosaeta are conducive to AD of NP.     

原位固氮剂在污泥堆肥过程中保氮机制

高温好氧堆肥技术虽然可有效处理有机固体废物，但常常会释放大量的氨气和造成氮素损失。本文以硫酸镁、磷酸二氢钾、硫酸镁+磷酸二氢钾（分别记为MgSO₄、KP和KPM处理组）为原位固氮剂，污泥和木屑为原料，进行高温好氧堆肥试验，研究以上原位固氮剂对污泥堆肥过程中的氨气挥发和氮素损失的影响。结果表明，硫酸镁（MgSO₄）对物料pH有显著的降低效应，添加硫酸镁使堆体高温期pH降低至8.17，低于硫酸镁+磷酸二氢钾（KPM）组（8.55）和对照（CK）组（8.90）。与CK相比，MgSO₄和KPM的NH₃累积释放量分别降低了34%和28%，反而KP组增加了35%。对比不同条件下XRD图谱可知，MgSO₄的固氮效应并不是由于MgNH₄PO₄·6H₂O的生成，而是由于其对pH的降低效应造成的。堆肥结束后，除了KP组，各处理条件下的种子发芽率值（germination index，GI）均不会对后续使用带来不利影响。     

城市污水厂剩余污泥对水中F-的吸附性能研究

利用城市污水处理厂的剩余污泥对水中F-进行吸附处理,通过污泥投加量、F-初始质量浓度、时间、pH等反应条件的研究,探讨除氟效果和影响因素。结果表明,室温下,污泥对F-的吸附在60 min后达到平衡;20 g/L的污泥投加量对10 mg/L含氟水的F-去除率可达83.1%;污泥可在3~10的较大pH范围内保持稳定的除氟效果。准二级动力学模型很好地拟合了污泥对F-的吸附行为,Langmuir和Freundlich模型均符合污泥对F-的吸附特性,热力学参数的计算表明该吸附过程是自发的放热反应。     

Study on migration characteristics of heavy metals during oil sludge incineration

Experimental and simulation studies on the migration characteristics of heavy metals during the incineration of OS were conducted with a tube furnace reactor and thermodynamic equilibrium calculation software FactSage, respectively. The results showed that when the incineration temperature increased from 800°C to 1100°C, the release rates of heavy metals such as Cr, Pb, Cu, Zn and Ni increased gradually and reached the maximum at 1000°C. When the excess air ratio increased from 1.0 to 1.4, the release rates of heavy metals such as Cr, Pb, Cu, Zn and Ni first decreased and then became steady. The content of gaseous hydroxide of Cr and gaseous chlorides of Pb and Cu increased while the chemical forms of Zn and Ni did not change obviously with the increase of combustion temperature or excess air ratio.     

Anaerobic co-digestion of food waste and FOG with sewage sludge – realising its potential in Ireland

The severe environmental pollution in many countries is caused by indiscriminate discharge of large quantities of food waste (FW), fat oil and grease (FOG) and sewage sludge (SS) to the environment. There are many possible treatment routes, but anaerobic digestion (AD) is now well accepted for treating several kinds of organic wastes. But AD of FW alone presents some operational challenges because of substrates and variability. Anaerobic co-digestion of two or more substrates is better than single substrate digestion. This can use a plant’s unused capacity, in line with the trend to renewable energy. Co-digestion technology, although well established in many European countries, is still in its infancy in Ireland. There are problems with different regulatory arrangements. They should be resolved. The paper reviews anaerobic co-digestion technology is reviewed, with special focus on possible application in Ireland.     

Hydrothermal Carbonization of Sewage Sludge: Analysis of Process Severity and Solid Content

Hydrothermal carbonization of sewage sludge was carried out with the aim to evaluate the influence of process severity and initial solid content. Response surface methodology was applied to model yield and C yield responses. Enhanced dewaterability performance was recorded under mild processing conditions. The treatment promoted concentration and immobilization of Pb, Cd, Ni, Zn, and Cu. Variation of the solid content showed a stronger influence than severity on average yield and C yield. Higher heating values (HHVs) and energy retention efficiencies (EREs) of hydrochars obtained at the lowest solid content displayed the lowest values. Hence, the energy requirements of a first dewatering step should be compared with the related improvement in terms of HHV and ERE when sludge is used as feedstock.