化学需氧量测定方法在环境监测站的应用研究

化学需氧量测定必须严格遵守流程,并使用科学的方法开展工作。本文对对环境监测站应用化学需氧量测定方法进行分析,总结测定方法种类,以及使用过程中的注意事项。帮助环境监测站使用科学的方式开展测定工作,保证测量结果精确性。

化学氧化法去除生活垃圾恶臭气体的效果研究

在逆流化学洗涤塔中分别采用芬顿、NaClO、H_(2)O_(2)溶液3种氧化剂作为洗涤液,对生活垃圾恶臭气体进行处理,测量处理前后气体的臭气(无量纲)、氨气和硫化氢浓度。实验表明,采用芬顿、NaClO、H_(2)O_(2)作为洗涤液的3组实验,臭气浓度去除效率分别为57.5%、56.3%、45.2%,氨气去除效率分别为69.4%、61.5%、69.7%,硫化氢去除效率分别为20.0%、37.5%、13.3%。综合考虑成本和操作性,使用NaClO处理生活垃圾恶臭气体最切实可行。

工业废水悬浮固体颗粒物污染下河道生态修复研究

悬浮固体颗粒物会导致水体浑浊度提高,降低水质透明度,阻碍水生生物的光合作用和觅食行为,对生态系统造成严重破坏。为了改善水质和恢复河道生态系统的健康状况,故提出工业废水悬浮固体颗粒物污染下河道生态修复方法。首先,介绍了研究区域、样本采集方法和研究方法;其次,设计了由膜分离设备、水生植物浮岛板、曝气复氧、循环泵四部分组成河道生态修复总线路,并通过对照区与生态修复区河道内悬浮固体颗粒物浓度含量对比,和悬浮固体颗粒物去除率、化学需氧量去除率、溶解氧含量三个指标展开河道生态修复效果分析。结果表明,该方法能够有效实现河道生态的修复。最后,提出了面对工业废水悬浮固体颗粒物污染下的河道生态修复建议。

分光光度法测定COD

分光光度法测定COD不需要四流,反应速度快;不需要滴定,可以直接测定。该方法快速、准确、成本低,在实 战中具有相当的可行性。

可见光/Fenton光催化处理高浓度味精废水的研究

对可见光辅助Fenton试剂处理味精废水的主要影响因素进行了研究。主要考察了光照强度,二价铁离子和双氧水摩尔配比((n(H2O2)/n(Fe2+)),反应时间及初始pH值等因素对废水的CODCr去除率的影响。通过单因素实验确定影响因素最佳范围并据此设计正交实验,确定了最佳反应条件为:在功率为60W的白炽灯照射下,pH值=3.5,n(H2O2)/n(Fe2+)=20 1,反应时间t=60min,此时CODCr去除率可达98.50%,各因素对反应的影响顺序为:pH>n(H2O2)/n(Fe2+)>反应时间。

Study on Piggery Anaerobic Fermentation Slurry Treated by Anoxic/Oxic Process

[Objective] The aim of this study was to provide a fast, stable and efficient piggery wastewater processing technology. [Method] The start-up process was studied through the experiment of piggery anaerobic fermentation slurry treated by Anoxic/Oxic （A/O） reactor. The process was divided into two stages： at the first stage, dominant micro flora were cultivated in Anoxic and Oxic reaction tanks respectively; at the second stage. Anoxic and Oxic reaction tanks were initiated jointly to gradually enhance water load and continued to cultivate and domesticate microorganisms, and finally the start-up process was completed. [ Result] The results showed that return mixture ratio and return sludge ratio was 2 and 1 respectively when the temperature reached 32 ±2 ℃. However. when aeration rate of Oxic reaction amounted to 0.5 m^3/h, the re- moval rate of COD and NH4^＋ -H were 89.87% and 89.31% respectively through practical operation within 50 days, which indicated that the start- up process through A/O reactor was successful. Conclusion This study can provide a scientific basis and reference for innocuous technique of piggery anaerobic fermentation slurry treatment.

Research into Uncertainty in Measurement of Seawater Chemical Oxygen Demand by Potassium Iodide-Alkaline Potassium Permanganate Determination Method

Using the glucose and L-glutamic-acid to prepare the standard substance according to the ratio of 1：1, and the artificial seawater and the standard substance to prepare a series of standard solutions, the distribution pattern of uncertainty in measurement of seawater COD is obtained based on the measured results of the series of standard solutions by the potassium iodide-alkaline potassium permanganate determination method. The distribution pattern is as follows： Uncertainty in measurement is big and not constant at the high end, but small and constant at the low end.

基于LLE-SVR的水质COD紫外光谱检测方法研究

化学需氧量(COD)是反映水体污染程度的重要指标之一。针对紫外可见光谱COD测量法数据波段多,易受干扰的问题,提出以局部线性嵌入法(LLE)结合支持向量机回归法(SVR)建立预测模型,来提高预测精度。首先,通过尝试预处理方法与模型分析方法(SVR和偏最小二乘回归法(PLSR))的不同组合来判断预测模型的效果,结果表明,"小波变换(WT)+SVR"效果较好。为了减少计算复杂度,提高运算效率,分别运用LLE和主成分分析算法(PCA)对数据降维,再分别结合SVR建立COD浓度预测模型。结果表明,利用"LLE+SVR"得到的COD浓度预测模型,其训练样本的均方误差为0.076030,测试样本均方误差为0.061477,分别小于"PCA+SVR"模型的0.216076和0.317303。这种方法使模型预测精度得到提高,为紫外可见光谱法检测水质COD浓度提供了一种可行的分析方法。

宁波市污水处理厂BOD_5/COD比值偏低原因分析

通过对宁波市污水处理厂进水 BOD5/COD比值偏低原因的调查 ,发现污水经过 2 4 h放置后 ,其 BOD5/COD值会有所下降。水样在 37℃条件下存放 2 4 h后 ,BOD5下降了4 1% ,BOD5/COD值平均下降 35 %。水样中混入脱水机滤液能使下降趋势更明显。但水样在 4℃下保存 2 4 h,BOD5平均下降幅度低于 10 % ,建议自动采样仪应具有冷藏功能。

节能减排是硬任务

环境是我们赖依生存的基本条件,是我们追求幸福的基础,我们发展经济的最终目标是为了更美好地生活。但是经济发展与环境保护在现阶段是有矛盾的,有些状况让人痛心担忧,我省有个污染工业非常集中的地方,近年癌症发病率始终保持在38%,80年代初期冒出的企业家,目前60-70%都得了癌症,赚来的钱基本都用在看病上了。有一个村,一下子就冒出5个白血病人。据专家估计,库兹涅茨环境倒U曲线的拐点。

Experimental study on micro-electrolysis technology for pharmaceutical wastewater treatment

Experiments were conducted to study the role of micro-electrolysis in removing chromaticity and COD and improving the biodegradability of pharmaceutical wastewater. The results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH could be advantageous to the removal of chromaticity. A retention time of 30 minutes was recommended for the process design of micro-electrolysis.

COD Removal Efficiencies of Some Aromatic Compounds in Supercritical Water Oxidation

Some aromatic compounds, phenol, aniline and nitrobenzene, were oxidized in supercritical water. It was experimentally found that the chemical oxygen demand (COD) removal efficiency of these organic compounds can achieve a high level more than 90% in a short residence time at temperatures high enough. As temperature, pressure and residence time increase, the COD removal efficiencies of the organic compounds would all increase. It is also found that temperature and residence time offer greater influences on the oxidation process than pressure. The difficulty in oxidizing these three compounds is in the order of nitrobenzene ＞ aniline ＞ Phenol. In addition, it is extremely difficult to oxidize aniline and nitrobenzene to CO2 and H2O at the temperature lower than 873.15 K and 923.15 K, respectively. Only at the temperature higher than 873.15 K and 923.15 K, respectively, the COD removal efficiencies of 90% of aniline and nitrobenzene can be achieved.

Treatment of flotation wastewater using biological activated carbon

A laboratory scale up-flow biological activated carbon(BAC) reactor was constructed for the advanced treatment of synthetic flotation wastewater. Biodegradation of a common collector(i.e., ethyl xanthate) for non-ferrous metallic ore flotation was evaluated. The results show that the two stages of domestication can improve microbial degradation ability. The BAC reactor obtains a chemical oxygen demand(COD) reduction rate of 82.5% for ethyl xanthate and its effluent COD concentration lowers to below 20 mg/L. The kinetics equation of the BAC reactor proves that the activated carbon layers at the height of 0 mm to 70 mm play a key role in the removal of flotation reagents. Ultraviolet spectral analysis indicates that most of the ethyl xanthate are degraded by microorganisms after advanced treatment by the BAC reactor.

Performance evaluation of a modified step-feed anaerobic/anoxic/oxic process for organic and nutrient removal

A pilot scale modified step-feed process was lmproved to increase nutrient/N ano P） ano organic removal operations from municipal wastewater. It combined the step-feed process and a method named ＂University of Cape Town （UCT）＂. The effect of nutrient ratios and inflow distribution ratios were studied. The highest uptake efficiency of 95% for chemical oxygen demand （COD） has been achieved at the inflow distribution ratio of 40/35/25. However, maximum removal efficiency obtained for total nitrogen （TN） and phosphorus at 93% and 78%, respectively. The average mixed liquor suspended solids （MLSS） was 5500 mg·L- 1. In addition, convenient values for dissolved oxygen （DO） concentration, and pH were obtained throughout different stages. The proposed system was identified to be an appropriate enhanced biological nutrient removal process for wastewater treatment plants owing to relatively high nutrient removal, sturdy sludge settle ability and COD removal.

A system combining microbial fuel cell with photobioreactor for continuous domestic wastewater treatment and bioelectricity generation

A coupled system consisting of an upflow membrane-less microbial fuel cell (upflow ML-MFC) and a photobioreactor was developed, and its effectiveness for continuous wastewater treatment and electricity production was evaluated. Wastewater was fed to the upflow ML-MFC to remove chemical oxygen demand (COD), phosphorus and nitrogen with simultaneous electricity generation. The effluent from the cathode compartment of the upflow ML-MFC was then continuously fed to an external photobioreactor for removing the remaining phosphorus and nitrogen using microalgae. Alone, the upflow ML-MFC produces a maximum power density of 481 mW/m 3 , and obtains 77.9% COD, 23.5% total phosphorus (TP) and 97.6% NH4+-N removals. When combined with the photobioreactor, the system achieves 99.3% TP and 99.0% NH4+-N total removal. These results show both the effectiveness and the potential application of the coupled system to continuously treat domestic wastewater and simultaneously generate electricity and biomass.

A New Spectrophotometric Method for Measuring COD of Seawater

This research studied a new spectrophotometric method for measuring the chemical oxygen demand （COD） of seawater. In this method, the COD was measured using a spectrophotometer instead of titrating with sodium thiosuiphate. The measuring wavelength was selected to be 470 nm, and the COD of three standard glucose solutions （COD = 0.5, 1.5 and 2.5 mgL^-1, respectively） and two seawater samples （from the South Yellow Sea and Jiaozhou Bay） were measured using the spectrophotometric method and titrimetric method respectively. The results showed that the spectrophotometric method was somewhat better than the titrimetric method. The relative standard deviation （RSD） of the spectrophotometric method was less than 2.7%, and the recovery of seawater samples ranged from 96.3% to 103.8%. In addition, the spectrophotometric method has other advantages such as expeditiousness, operation simplicity, analysis automatization, etc. Therefore the spectrophotometric method can be used to measure the COD of seawater with satisfactory results.

Environmental capacity of chemical oxygen demand in the Bohai Sea: modeling and calculation

A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the surface in the Bohai Sea in August, 2001 with field observations, shows that the model simulates the dataset reasonably well. The Laizhou Bay, Bohai Bay, and Liaodong Bay were contaminated heavily near shore. Based on the optimal discharge flux method, the Environmental Capacity (EC) and allocated capacities of COD in the Bohai Sea are calculated. For seawater of Grades I to IV of the Chinese National Standard, the ECs of COD in the Bohai Sea were 77×104 t/a, 116×104 t/a, 154×104 t/a and 193×104 t/a, respectively. The Huanghe (Yellow) River pollutant discharge accounted for the largest percentage of COD at 14.3%, followed by that of from the Liugu River (11.5%), and other nine local rivers below 10%. The COD level in 2005 was worse than that of Grade II seawater and was beyond the environmental capacity. In average, 35% COD reduction is called to meet the standard of Grade I seawater.

Water quality and eutrophication in the Guangzhou Sea Zone of the Pearl River estuary

To gain a better understanding of water quality and eutrophication, we investigated the seasonal and spatial distribution of water quality at 17 stations in the Guangzhou Sea Zone （GZSZ）. Nutrients, chlorophyll-a （Chl-a）, salinity, chemical parameters were determined in February, May, oxygen demand, and other physical and chemical August and October from 2005 to 2007. The concentrations showed ranges of 93.2-530.4 μmol/L for dissolved inorganic nitrogen （DIN）, 0.62-3.16 μmol/L for phosphate （PO4-P） and 50-127 μmol/L for silicate （SiO3-Si）, The results indicated that DIN was strongly influenced by domestic sewage coming from Guangzhou City and NO3-N was the main form of DIN in most areas, while concentrations of phosphate and silicate were generally controlled by Pearl River runoff, land-based sources along the land or islands, and algae assimilation. N/P ratios were very high in both dry season and wet season, and varied from 57 to 667, suggesting that P was potentially the most limiting nutrient in the GZSZ. The concentrations of Chl-a were 3-96 μg/L, and were highly correlated with the distribution characteristics of COD, The concentrations of nutrients have increased over the past two decades （1982-2007）. This means it is necessary to control the input of nutrients to the GZSZ, especially that of phosphate.

财政部关于印发《城镇污水处理设施配套管网以奖代补资金管理暂行办法》的通知

2007年11月22日财建[2007]730号有关省、自治区、直辖市财政厅(局),新疆生产建设兵团财务局:为支持中西部地区城镇污水处理设施建设。