Experimental analysis of a nitrogen removal process simulation of wastewater land treatment under three different wheat planting densities

Nitrogen contaminant transport, transformation and uptake simulation experiments were conducted in green house under three different planting density of winter wheat. They were Group A, planting density of 0.0208 plants/cm 2, Group B, 0.1042 plants /cm 2, and Group C, 0.1415 plants/cm 2. The capacity and ratio of nitrogen removal were different on three kinds of conditions of wastewater land treatment. From analysis of wastewater treatment capacity, wastewater concentration and irrigation intensity for Group C were suitable and nitrogen quantity added was 2 times of that for Group B, 2.6 times for Group A while nitrogen residue was only 7.06%. Hence, wastewater irrigation and treatment design with purpose of waste water treatment should select the design with maximum capacity, optimal removal ratio and least residue in soil, which was closely related to crop planting density, crop growth status and also background nitrogen quantity in soil.

ABR/CASS法处理屠宰废水

介绍了采用折板厌氧反应器(ABR)/循环活性污泥系统(CASS)处理屠宰废水的工程实例。实际运行结果表明:工艺可行、管理方便,投资、运行费用低,处理效果稳定,出水水质可达到《肉类加工工业水污染排放标准》(GB 13457—1992)一级标准。

CASS法在湖州市碧浪污水处理厂的应用

湖州市碧浪污水处理厂采用了CASS处理工艺 ,它的主要特点是高效、稳定、工艺流程简单 ,在有效去除污水中有机污染物的同时 ,具有脱氮除磷的良好性能 ,同时污水处理厂的高度自动化控制水平可以大大降低污水厂的运行成本。本研究介绍了污水处理厂的主要处理工艺。

Inorganic nitrogen removal of toilet wastewater with an airlift external circulation membrane bioreactor

Removal of inorganic nitrogen （inorganic-N） from toilet wastewater, using a pilot-scale airlift external circulation membrane bioreactor （AEC-MBR） was studied. The results showed that the use of AEC-MBR with limited addition of alkaline reagents and volumetric loading rates of inorganic-N of 0.19-0.40 kg inorganic-N/（m^3·d） helped achieve the desired nitrification and denitrification. Furthermore, the effects of pH and dissolved oxygen （DO） on inorganic-N removal were examined. Under the condition of MLSS at 1.56-2.35 g/L, BODs/ammonia nitrogen （NH4＋-N） at 1.0, pH at 7.0-7.5, and DO at 1.0-2.0 mg/L, the removal efficiencies of NH4^＋-N and inorganic-N were 91.5% and 70.0%, respectively, in the AEC-MBR. The cost of addition of alkaline reagent was approximately 0.5-1.5 RMB yuan/m^3, and the energy consumption was approximately 0.72 kWh/m^3 at the flux of 8 L/（m^2-h）.

Occurrence and Roles of Comammox Bacteria in Water and Wastewater Treatment Systems:A Critical Review

Nitrogen removal is a critical process in water treatment plants(WIPs)and wastewater treatment plants(WWTPs).The recent discovery of a novel bacterial process,complete ammonia oxidation(comammox,CMX),has refuted a century-long perception of the two-step conversion of NH3to NO3-.Compared with canonical nitrifiers,CMX bacteria offer undeniable advantages,such as a high growth yield propensity and adaptability to nutrient-and growth-limiting conditions,which collectively draw attention to validate the aptness of CMX bacteria to wastewater treatment.As there has been no comprehensive review on the relevance of CMX bacteria for sustainable water and wastewater treatment,this review is intended to discuss the roles and applications of CMX in the removal of nitrogen and pollutants from water and wastewater.We took into account insights into the metabolic versatilities of CMX bacteria at the clade and subclade levels.We focused on the distribution of CMX bacteria in engineered systems,niche differentiation,co-occurrence and interactions with cano nical nitrifiers for a better understanding of CMX bacteria in terms of their ecophysiology.Conceptualized details on the reactor adaptability and stress response of CMX bacteria are provided.The potential of CMX bacteria to degrade micropollutants either directly or co-metabolically was evaluated,and these insights would be an indispensable advantage in opening the doors for wider applications of CMX bacteria in WWTPs.Finally,we summarized future directions of research that are imperative in improving the understanding of CMX biology.

Research Development and Application of Nitrogen and Phosphorus Removal in Sequencing Batch Biofilm Reactor

Frequent variations of the wastewater quality and quantity and other uncertain factors are the challenges faced by many wastewater treatment plants during the operation. Sequencing batch biofilm reactor（ SBBR） process provides a new idea for an effective solution to this problem. This paper introduces the basic processes and characteristics of the sequencing batch biofilm reactor（ SBBR） process,and summarizes the research status of this process in wastewater treatment. Factors affecting the nitrogen and phosphorus removal effect of the SBBR process are also analyzed.

High nitrogen removal from wastewater with several new aerobic bacteria isolated from diverse ecosystems

Three new bacteria HS-03, HS-043 and HS-047 isolated from different ecosystems were found capable of aerobic denitrification. The potential application of these strains in wastewater treatment under aerobic conditions was investigated, These three bacteria all presented high nitrogen removal from wastewater that more than 98% of 10 mmol/L nitrate could be removed in 12--24 h by adding cheap external carbon source and low concentration of iron as well as molybdate. The mechanism at molecular level was analyzed. The success of this aerobic denitrification applied to wastewater treatment may serve as an alternative to enhance the practical nitrogen removal from wastewater. Main biochemical and physiological features of these strains were characterized. The 16S rDNA sequences were compared with the published data in GenBank by using BLAST. The results of phenotype and genotype proved that strain HS-03 and HS-047 belonged to Pseudomonas stutzeri and Pseudomonas pseudoalcaligenes respectively. Strain HS-043 was identified as Delftia clcidovorans of which denitrifying activity has not previously been explored.

Treatment of Wastewater with Modified Sequencing Batch Biofilm Reactor Technology

This paper describes the removal of COD and nitrogen from wastewater with modified sequencing batch biofilm reactor. The strategy of simultaneous feeding and draining was explored.The results show that introduction of a new batch of wastewater and withdrawal of the purified water can be conducted simultaneously with the maximum volumetric exchange rate of about 70%.Application of this feeding and draining mode leads to the reduction of the cycle time, the increase of the utilization of the reactor volume and the simplification of the reactor structure. The treatment of a synthetic wastewater containing COD and nitrogen was investigated. The operation mode of F(D) O ( i.e ., simultaneous feeding and draining followed by the aerobic condition) was adopted. It was found that COD was degraded very fast in the initial reaction period of time, then reduced slowly and the ammonia nitrogen and nitrate nitrogen concentrations decreased and increased with time respectively, while the nitrite nitrogen level increased first and then reduced. The relationship between the COD or ammonia nitrogen loading and its removal rate was examined, and the removal of COD, ammonia nitrogen and total nitrogen could exceed 95%, 90% and 80% respectively. The fact that nitrogen could be removed more completely under constant aeration (aerobic condition) of the SBBR operation mode is very interesting and could be explained in several respects.

Characterization of the start-up period of single-step autotrophic nitrogen removal in a sequencing batch reactor

The characteristics of the start-up period of single-step autotrophic nitrogen removal process were investigated. The autotrophic nitrogen removal process used a sequencing batch reactor to treat wastewater of medium to low ammonia-nitrogen concentration, with dissolved oxygen (DO), hydraulic retention time (HRT) and temperature controlled. The experimental conditions were temperature at (30±2) °C, ammonia concentration of (60 to 120) mg/L, DO of (0.8 to 1.0) mg/L, pH from 7.8 to 8.5 and HRT of 24 h. The rates of nitrification and nitrogen removal turn out to be 77% and 40%, respectively, after a start up period going through three stages divided according to nitrite accumulation: sludge domestication, nitrifying bacteria selection and sludge adaptation. It is demonstrated that dissolved oxygen is critical to nitrite accumulation and elastic YJZH soft compound packing is superior to polyhedral hollow balls in helping the bacteria adhere to the membrane.

Research Progress on Energy Plants in Piggery Wastewater Treatment

Large-scale pig-raising can discharge a great deal of wastewater,which contains high content of organic matter,ammonia nitrogen and suspended solids.The improper treatment of the piggery wastewater can lead to serious environmental problems. As a liquid fertilizer,piggery wastewater is relatively low in fertilizer efficiency and high in transportation cost,so it is very necessary to treat it in situ. Energy plants have the advantages of rapid growth,large biomass,strong tillering ability and developed root system. Therefore,energy plants can be used to absorb and transform the pollutants( like nitrogen and phosphorus) in piggery wastewater into the components of plants,as well as form the rhizosphere environment which is conducive to microbial growth,so as to enhance the effects of nitrogen and phosphorus removal. The obtained energy plants can be recycled as the raw materials for biogas to increase the production of biogas,which brings economic benefits while solving the environmental problems caused by piggery wastewater.

Effects of Aeration Rates and Patterns on Shortcut Nitrification and Denitrification

The effects of aeration rates and aeration patterns on the oxidation of ammonia-nitrogen into nitrite were investigated. The influent high ammonia-nitrogen synthetic wastewater resembled to those of the catalytic process of the petrochemical refinery. The method involved the biological shortcut nitrification and denitrification lab-scale’s sequencing batch reactor (SBR) process based on intermittent aerations and aeration patterns. All the operations were carried out in a 20 L working volume SBR bioreactor, and the influent synthetic wastewater’s concentration was always 1000 mg/L ammonia-nitrogen NH4-N concentration at a C/N (carbon/nitrogen) ratio of 2.5:1. Effective shortcut nitrification to nitrite was registered at 1.1 mg-O2/L (i.e. 9 L-air/min) with 99.1% nitrification efficiency, 99.0% nitritation rate and 2.6 mg-NO3--N/L nitrate concentration. The best results with 99.3% nitrification efficiency were recorded when operating at 1.4 mg-O2/L (i.e. 12 L-air/min). According to these experiments, it results that the nitrite accumulation rate was related to aeration rate and cycle’s duration. However, at 1.7 mg-O2/L (i.e. 15 L-air/min), the system was limited by an increase in nitrate concentration with more than 5 mg/L which could be a point of reverse to conventional nitrification. The best total nitrogen (TN) removal was about 71.5%.

固定化异养硝化-好氧反硝化菌在污水生物强化中的研究进展

异养硝化-好氧反硝化(Heterotrophic nitrification-aerobic denitrification,HN-AD)菌可以在有机碳存在的好氧条件下实现同时硝化和反硝化,广泛应用于各类污水处理过程中。综述了HN-AD菌株的脱氮特性和代谢途径,总结了其在污水处理中的应用和研究现状,比较了不同载体材料的优缺点,重点讨论了固定HN-AD菌株提高反应器处理效果和稳定性的作用机理。最后,展望了固定化HN-AD菌株在污水处理中面临的挑战和未来的研究方向。

A-O模式MBBR工艺对村镇社区污水的脱氮效果

采用快速排泥法对硝化型和反硝化型MBBR反应器进行启动,并形成A-O模式工艺处理村镇生活污水。结果显示,通过快速排泥法,可以分别在20 d和10 d内完成硝化生物膜和反硝化生物膜的培养;在填充率为40%时,(20.0±0.5)℃水温条件下填料的平均硝化速率和反硝化速率分别为0.48 kgN/(m^(3)·d)和0.55 kgN/(m^(3)·d);当水温为(16.2±2.4)℃时,不投加外碳源,A-O模式的MBBR工艺出水氨氮和总氮可达到一级A标准;反硝化作用主要发生在缺氧池前端,硝化作用主要发生在好氧池后端。高通量测序结果显示,缺氧池前端反硝化菌主要为异养反硝化菌(相对丰度为19.14%),好氧池从前端到后端,硝化细菌菌属逐渐增加(相对丰度从3.09%增加到11.88%),好氧区填料存在一定比例的反硝化菌属(相对丰度为1.35%~4.11%)。A-O模式纯膜MBBR工艺启动迅速,脱氮效率高,系统简单、易于维护,适用于村镇污水处理。

移动床生物膜反应器-生物滤池脱氮除磷中试研究

采用移动床生物膜反应器-生物滤池(MBBR-BF)一体化污水处理设备进行实际污水中试试验,考察曝气量对一体化设备挂膜启动阶段污染物去除效果的影响,探究低温环境下一体化设备适应性及污染物处理能力。结果表明:曝气量降低对COD和TN去除率影响较小,而NH_(3)-N与TP的去除率随之下降,NH_(3)-N平均去除率由87.46%降至48.64%,TP平均去除率由72.41%降至54.66%;常温环境下COD、NH_(3)-N、TN、TP平均去除率分别为92.48%、94.41%、49.39%和61.63%,低温环境运行对污染物去除效果有明显影响。中试应用试验状况良好,一体化设备在冬季低温环境下运行状况正常,可为农村生活污水的有效处理提供重要参考。

Insights into a novel nitrogen removal process based on simultaneous anammox and denitrification(SAD) following nitritation with in-situ NOB elimination

Simultaneous anammox and denitrification(SAD) is an efficient approach to treat wastewater having a low C/N ratio;however, few studies have investigated a combination of SAD and partial nitritation(PN). In this study, a lab-scale up-flow blanket filter(UBF) and zeolite sequence batch reactor(ZSBR) were continuously operated to implement SAD and PN advantages, respectively. The UBF achieved a high total nitrogen(TN) removal efficiency of over 70% during the start-up stage(days 1–50), and reached a TN removal efficiency of 96%in the following 90 days(days 51–140) at COD/NH_(4)^(+)-N ratio of 2.5. The absolute abundance of anammox bateria increased to the highest value of 1.58 × 107copies/μL DNA;Comamonadaceae was predominant in the UBF at the optimal ratio. Meanwhile, ZSBR was initiated on day 115 as fast nitritation process to satisfy the influent requirement for the UBF. The combined process was started on day 140 and then lasted for 30 days, during the combined process, between the two reactors, the UBF was the main contributor for TN(66.5% ± 4.5%)and COD(71.8% ± 4.9%) removal. These results demonstrated that strong SAD occurred in the UBF when following a ZSBR with in-situ NOB elimination. This research presents insights into a novel biological nitrogen removal process for low C/N ratio wastewater treatment.

郑州某大型污水处理厂运行经验及工艺调控分析

污水厂超负荷下稳定运行一直是研究者关注的热点,高效脱氮除磷是稳定运行过程中的难点。郑州某污水处理厂采用前置预缺氧改良A^(2)/O工艺,处理水量是设计值的1.2~1.8倍,进水BOD_(5)/COD、BOD_(5)/TN、BOD_(5)/TP范围分别为0.19~0.88、1.38~7.21、13.12~89.17,采用多点进水、提高内回流比、精确曝气等运行方式,分析了污水全流程中氮磷的变化。结果表明,当进水均匀分配在预缺氧、厌氧、缺氧工段,内回流比为400%,好氧池DO质量浓度为0.5 mg/L以下时,COD、TN、TP去除率达到90.4%、83%、98.55%,优于《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A排放标准,部分指标达到《地表水质量标准》(GB 3838—2002)Ⅲ类标准。

厌氧铁氨氧化脱氮除磷效能及稳定性研究

为探究厌氧铁氨氧化(Feammox)污水处理效能及稳定性,考察了铁氧化物类型、硫限制和低温(4℃)对Feammox脱氮除磷的影响,并分析了污泥与微生物特性。结果表明,添加硫酸盐和水铁矿的实验组具有较好的脱氮除磷效果,氨氮和总磷去除率分别超过84%和98%,各实验组氨氧化产物均以硝态氮/亚硝态氮为主,并通过反硝化去除。微生物分析表明,添加硫酸盐和水铁矿、硫酸盐和磁铁矿的实验组中具有较高丰度的氨氧化细菌,硫限制和低温条件下则具有较高丰度的异养反硝化细菌。综上,Feammox具有较稳定的脱氮除磷效果,硫限制和磁铁矿作为铁源不影响其氨氧化效率,但低温明显降低氨氧化效率。

Microbiome analysis and-omics studies of microbial denitrification processes in wastewater treatment: recent advances

Nitrogen pollution is an increasingly severe worldwide problem because of drainage of nitrogen-containing wastewater and intensive application of nitrogen-containing fertilizers. Denitrification, a key process in nitrogen cycles, is commonly employed for nitrogen removal in engineered wastewater treatment systems. Biological denitrification is performed by denitrifying microbes(bacteria) that use nitrate as terminal electron acceptor. Better understanding the functions of diverse microbial populations in denitrification-based wastewater treatment systems, and the interactions of these populations with operating environments, is essential for improving both treatment performance and system stability. Recent advances in "meta-omics"(e.g., genomics, transcriptomics, proteomics, metabolomics), other molecular biology tools, and microbiome analysis have greatly enhanced such understanding. This minireview summarizes recent findings regarding microbial community structure and composition, key functional microbes and their physiology, functional genes involved in nitrogen cycle, and responses of microbes and their genes to changes of environmental factors or operating parameters, in denitrification processes in wastewater treatment systems. Of particular interest are heterotrophic denitrification systems(which require alternative organic carbon sources) and the autotrophic denitrification systems(which do not require an external carbon source). Integrated microbiome and-omics approaches have great future potential for determination of optimal environmental and biotechnological parameters,novel process development, and improvement of nitrogen removal efficiency and system stability.

城市污水处理厂前置反硝化BIOFOR工艺的设计与运行

结合厦门市筼筜污水处理厂的工程设计,介绍了前置反硝化BIOFOR工艺的特点、设计参数、技术经济指标、试运行情况等。该工艺具有占地面积小、除污效率高、脱氮除磷效果好等特点,宜于推广。

化工废水的蒸氨环保处理技术研究

传统技术在实际应用中对化工废水处理效果不佳,废水氨氮去除率较低,且废水处理用时较长,处理效率较低,因此提出化工废水的蒸氨环保处理技术研究。根据实际情况准备化学试剂、仪器设备,对蒸氨环保处理装置功能校验,并对化工废水过滤、沉淀等预处理;导入蒸氨环保处理装置,对废水pH值调节、氨氮吹脱处理,利用沸石对化工废水吸附处理,并经过过滤除掉析出的废弃物,以此完成化工废水的蒸氨环保处理。经实验证明,设计技术氨氮去除率较高,且废水处理用时较短,处理效率较高,在化工废水净化处理方面具有良好的应用前景。