哈希COD测定仪替代消解液的开发

为了降低COD测定成本、减少试剂污染和缩短测定时间，利用哈希（HACH）仪器开发了测定0～1 000 mg/L COD的消解液。通过计算和对比试验，自配消解液在组成上接近于HACH原装试剂，消解过程的氧化电位与国标重铬酸盐法的氧化电位相当。自配消解液不仅可以替代昂贵的进口试剂，而且样品消解时间由原来的2 h缩短至35 min，特别是在进行突发水体环境污染事件的应急监测时，能够快速提供水体受COD污染的结果。实验证明，采用自配消解液与采用HACH原装试剂及国标重铬酸盐法测定结果相比，数据无显著差异，测定结果     

污水中化学需氧量测试方法条件化与实践

化学需氧量（Chomical Oxygen Demand简称COD）是在一定条件下，用强氧化剂处理水样时所消耗的氧化剂的量，以氧的mg／L表示，它反映了水体受还原性物质污染的程度，是进行水质监测与评价的一个重要指标。水中还原性物质包括有机物、亚硝酸盐、亚铁盐、硫化物等，无论是有机废水、石化废水、燃料废水、印染废水、制药废水、皮革废水，还是生活污水，都必需经过处理，使其COD值达到环境排污标准要求才允许排放。因此是环境监测中的重要必测项目。目前，水样中COD监测一般采用重铬酸钾法（国标法），利用敞开式加热回流装置消解水样中的有机污染物。该法的加热回流装置占用空间大，水样消解时间长，批量测定较困难，硫酸银催化剂用量大，因而分析费用较高，作为掩蔽剂的硫酸汞易造成二次污染，消耗大量电力和冷却水等不足，不能适应日益繁重的环境污染监测需要。因此，寻求一种既简便、节省试剂，又能准确快速测定COD的方法是很必要的。分光光度法测定水样中的COD，即将试样在密闭的反应管内回流消解后，直接置入分光光度计中测定吸光度，计算出COD值。分光光度法操作简便，节省试剂。     

无汞开管法快速测定工业废水中的COD

采用无汞开管法快速测定COD，以硫酸－磷酸为介质、重铬酸钾为氧化剂、硫酸银为催化剂，并采用硝酸银和硫酸铬钾排除氯离子的干扰，在玻璃式管中对样品进行消解（反应温度为160－165℃，加热时间为15min），消解后剩余的重铬酸盐用滴定法或分光光度法测定。试验结果表明，该法的检测限为10．9mg/L，对COD的测定范围为40－800mg/L，当COD值为85mg/L时，容许的氯离子最高含量为1500mg/L。由于该法不使用剧毒的汞盐而避免了对环境的污染。     

HACH微回流法测定水中COD的方法探讨与改进

用哈希微回流法测定水中COD操作简单、方便。但在实际应用中还存在着一些技术问题。本文提出HACH微回流法在检测过程中的注意事项以及改进方法,并根据厂家提供消解液配方自行配制消解液,代替了进口试剂,降低了检测成本,通过改进的HACH微回流法是一种操作筒单、准确、经济、可靠实用的分析方法。     

粉末活性炭去除污水处理厂二沉池出水中难降解COD的试验研究

利用粉末活性炭进行多组烧杯试验,研究粉末活性炭用于污水处理厂去除难降解COD的工艺。通过改变粉末活性炭粒径、投加量,对污水处理厂二沉池出水进行批试验,使用仪器消解法、分光光度计测定COD,分析粉末活性炭去除COD的影响因素。试验表明:粉末活性炭与污水的充分接触对其效用的发挥至关重要。粉末活性炭粒径越小、投加量越多、停留时间越长,去除COD的效果越好。粉末活性炭在污水中的最佳停留时间为30min。在工程应用中,粉末活性炭最佳投加量的确定应当充分考虑原水水质以及经济成本。     

自配消解液应用HACH微回流法测定水中COD的探讨与改进

用哈希微回流法测定水COD操作简单、方便，但在实际应用中还存在着一些技术问题。本文提出HACH微回流法在检测过程中的注意事项以及改进方法，并根据厂家提供消解液配方自行配制消解液，代替了进口试剂，降低了检测成本，通过改进的HACH微回流法是一种操作简单、准确、经济、可靠实用的分析方法。     

COD测定仪用消解液的配制与应用

分析了采用COD仪测定COD所用消解液和反应液的紫外－可见光谱特征及其主要影响因素，从而为自配消解液提供了光谱学依据。试验证明采和自配消解液测定COD能大幅度降低分析成本，而且测定精密度与准确度能符合要求。     

哈希发布20min消解COD预制管试剂

哈希公司发布最新一代20 min消解COD预制管试剂。该产品在保证准确性和可靠性的基础上,缩短了消解时间,简化了分析过程,大大提升了COD测试效率。     

用高压灭菌器快速消解、分光光度法测定COD

本文研究了用高压消毒锅重铬酸钾法消解环境水样，用分光光度计测定COD，本法具有快速、简便、准确度高的特点，有良好的精密度。     

化学需氧量测定改进方法的研究进展

综述了COD测定改进方法的发展和研究现状,在指出国标重铬酸钾法不足的基础上,阐述了现有测定方法的改进,如消解方法的改进、替代银催化剂的研究、氯离子干扰的消除等,同时介绍了几种与国标法完全不同的COD测定的新方法,从而为化学需氧量的测定提供了更准确更先进的方法。     

消解/分光光度法测定废水中CODCr的研究

文章对废水中CODCr测定方法中的快速消解/分光光度法、微波消解/分光光度法和回流消解/滴定法进行了比较.结果显示:快速消解/分光光度法和微波消解/分光光度法两种方法的准确度和精密度都达到质量控制的要求,两种方法分光光度法与回流消解/滴定法测定标准水样的方法相比,CODCr测定结果稍微偏高,但对于废水样品,两种方法的测定结果没有显著差异.快速消解/分光光度法和微波消解/分光光度法值得在环境监测工作中推广应用.     

Silage effluent digestion by an upflow anaerobic filter

Silage effluent is generally regarded as one of the major agricultural pollutants of water courses. Efficient anaerobic digestion of silage effluent was achieved by a 3-day hydraulic retention in an upflow anaerobic filter. The filter was a laboratory scale unit containing a limestone chip support matrix. At loading rates ranging from 7.8 to 14.2 kg COD m⁻³ active volume day⁻¹, the average COD removal obtained ranged from 86 to 89% with a TOA removal of 82–88%. The methane content of the biogas produced ranged from 81 to 88%. The rate of COD conversion to CH₄ was independent of the loading rate under the conditions tested and the observed efficiency averaged 0.357 m¹ CH₄(STP) kg⁻¹ COD introduced to the reactor.The reactor tolerated considerable variation in influent pH without any apparent decrease in digestion efficiency. It is apparent from the results obtained that a reactor which is in routine use for slurry digestion may also be utilised for silage effluent digestion on a seasonal basis.     

The mesophilic and thermophilic anaerobic digestion of coffee waste containing coffee grounds

The anaerobic digestion of waste water containing significant levels of coffee grounds was assessed in mesophilic and thermophilic batch studies and CSTRs fed daily. A 58% reduction in VS was seen in both batch studies. Proximate compositional analysis showed that the waste had a high lipid component (26–33%). Levels of lipid, hemicellulose, α-cellulose and lignin were determined before and after digestion. These components were reduced as follows: lipid by 87% in the mesophilic study and 65% in the thermophilic study, α-cellulose by 51% in both mesophilic and thermophilic batch studies, hemicellulose by 22% in the mesophilic studies and 64% in the thermophilic studies. The lignin component was not reduced in either study. Mesophilic continuous digestion was achieved at a loading rate of 1.3 kg COD m⁻³ day⁻¹ (25 day HRT) for 99 days. Addition of sodium bicarbonate alone was not sufficient for long term anaerobic digestion. Addition of Ca(OH)₂, nitrogen, phosphorus and trace elements, however, gave successful digestion with COD and VS removal of 60% and a gas production rate of 0.34 11⁻¹ day⁻¹ (65–70% methane). Low levels of TVFA and high levels of bicarbonate alkalinity were present. Thermophilic digestion could be established at 1.6 kg COD m⁻³ day⁻¹ (20 day HRT) with the addition of sodium bicarbonate alone, or Ca(OH)₂ with nitrogen, phosphorus and trace elements. However long term digestion could not be established beyond 50 days without a increase in TVFA occurring.     

固定化芽孢杆菌修复油污染地表水的研究

采用改进的聚乙烯醇-硼酸包埋固定化微生物法固定芽孢杆菌，并用于处理油污染地表水。结果表明，固定化芽孢杆菌对地表水中油和COD的去除能力均大于游离茵，作用120h后固定化芽孢杆菌对油的去除率为80．1％，对COD的去除率为79．4％；游离菌对油的去除率为50．4％，对COD的去除率为66．5％。采用改进的聚乙烯醇-硼酸法制得的固定化颗粒机械强度高、传质性能好、水溶膨胀性小，扫描电子显微镜观察表明，改进后的聚乙烯醇凝胶微观结构更适合芽孢杆菌生长。可见，采用微生物固定化技术修复油污染地表水是可行的。     

内电解法处理难降解有机废水试验研究

采用内电解法对081特种难降解特种废水进行试验研究,分析了废水来源及水质情况,对内电解法反应机理进行了介绍,总结了不同pH值、不同碳铁比、不同接触时间、不同进水COD对废水COD去除率的影响,为后续处理创造了条件。     

Anaerobic digestion of tannery soak liquor with an aerobic post-treatment

The leather industry occupies a place of prominence in the Indian economy due to its massive potential for employment, growth and exports. The potential environmental impact of tanning is significant. This study focuses on tannery soak liquor, generated by the soaking of hides and skins, which is characterised by high organic load and high salinity. For these reasons, the soak liquor should be segregated and pre-treated separately before being mixed with the composite wastewater, made of all other streams mixed together. The anaerobic digestion of tannery soak liquor was studied using a UASB. COD removal reached 78% at an OLR of 0.5 kg COD m(-3) d(-1), a HRT of 5 days and a TDS concentration of 71 gl(-1). The combination of the UASB with an aerobic post-treatment enhanced the performance of the overall wastewater treatment process and the COD removal efficiency of the combined anaerobic/aerobic treatment system reached 96%. However, for effective operation, the system had to be operated at very low OLRs, which affects the economic viability of such a process.     

Athermal microwave effects for enhancing digestibility of waste activated sludge

A bench scale industrial microwave (MW) unit equipped with fiber optic temperature and pressure controls within pressure sealed vessels successfully simulated conventional heating (CH, in water bath). By identical temporal heat temperature profiles for waste activated sludge (WAS) samples, evaluation of the athermal effects of MW irradiation on WAS floc disintegration and anaerobic digestion was achieved. In a pretreatment range of 50-96 degrees C, both MW and CH WAS samples resulted in similar particulate chemical oxygen demand (COD) and biopolymer (protein and polysaccharide) solubilization and there was no discernable MW athermal effect on the COD solubilization of WAS. However, biochemical methane potential (BMP) tests showed improved biogas production for MW samples over CH samples indicating that the MW athermal effect had a positive impact on the mesophilic anaerobic biodegradability of WAS. BMP tests also showed that despite mild inhibition in the first 7d, MW acclimated inoculum digesting pretreated (to 96 degrees C) WAS, produced 16+/-4% higher biogas compared to the control after 15 d of mesophilic batch digestion. However, initial acute inhibition was more severe for non-acclimated inoculum requiring recovery time that was two times longer with only 4+/-0% higher biogas production after 17d. Inoculum acclimation not only accelerated the production of biogas, but also increased the extent of the ultimate mesophilic biodegradation of MW irradiated WAS (after 15-27 d).     

应用COD消解装置测定城市污水CODcr

研究型用COD消解装置测定城市污水CODcr，分析了在一定条件下，消解时间对CODc，测定结果的影响，以确定最佳消解时间。     

Biological disc filtration for tropical waste treatment Experimental studies

Experimental biological disc filtration units incorporating anaerobic digestion were very efficient under tropical conditions in treating organic wastes with COD near 1000 mg 1⁻¹. Up to 95 per cent COD removal was achieved at an aerobic volumetric loading of 4 kg COD m⁻³ day, giving 6 h detention. An anaerobic compartment of the same capacity as the aerobic section effected a high degree of digestion of the biological solids sloughing off the discs. Advantages of the process are ability to absorb shock loadings and nutrient-deficient wastes, low land requirements, low capital cost and simplicity of operation.     

Treatment of olive oil mill wastewater by combined process electro-Fenton reaction and anaerobic digestion

In this work, we investigated an integrated technology for the treatment of the recalcitrant contaminants of olive mill wastewaters (OMW), allowing water recovery and reuse for agricultural purposes. The method involves an electrochemical pre-treatment step of the wastewater using the electro-Fenton reaction followed by an anaerobic bio-treatment. The electro-Fenton process removed 65.8% of the total polyphenolic compounds and subsequently decreased the OMW toxicity from 100% to 66.9%, which resulted in improving the performance of the anaerobic digestion. A continuous lab-scale methanogenic reactor was operated at a loading rate of 10 g chemical oxygen demand (COD)l(-1) d(-1) without any apparent toxicity. Furthermore, in the combined process, a high overall reduction in COD, suspended solids, polyphenols and lipid content was achieved by the two successive stages. This result opens promising perspectives since its conception as a fast and cheap pre-treatment prior to conventional anaerobic post-treatment. The use of electro-coagulation as post-treatment technology completely detoxified the anaerobic effluent and removed its toxic compounds.