二相厌氧-混凝法处理制浆造纸综合废水的工艺设计及调试

湖南某造纸厂采用二相厌氧 混凝法处理制浆造纸综合废水取得了显著效果 ,CODCr排放总量削减率达 80 % ,水体水质明显改善。本文介绍了该工程的工艺设计及调试。     

城市生活污水厌氧生物处理发展现状

回顾了国内外污水厌氧生物处理工艺的发展情况,着重分析了中国城市污水的特点以及厌氧生物处理工艺在城市生活污水处理中的应用情况。     

Fate of ah receptor agonists during biological treatment of an industrial sludge containing explosives and pharmaceutical residues

GOAL, SCOPE AND BACKGROUND: Sweden is meeting prohibition for deposition of organic waste from 2005. Since 1 million tons of sludge is produced every year in Sweden and the capacity for incineration does not fill the demands, other methods of sludge management have to be introduced to a higher degree. Two biological treatment alternatives are anaerobic digestion and composting. Different oxygen concentrations result in different microbial degradation pathways and, consequently, in a different quality of the digestion or composting residue, It is therefore necessary to study sludge treatment during different oxygen regimes in order to follow both degradation of compounds and change in toxicity. In this study, an industrial sludge containing explosives and pharmaceutical residues was treated with anaerobic digestion or composting, and the change in toxicity was studied. Nitroaromatic compounds, which are the main ingredients of both pharmaceutical and explosives, are well known to cause cytotoxicity and genotoxicity. However, little data are available concerning sludge with nitroaromatics and any associated dioxin-like activity. Therefore, we studied the sludge before and after the treatments in order to detect any changes in levels of Ah receptor (AhR) agonists using two bioassays for dioxin-like compounds. METHODS: An industrial sludge was treated with anaerobic digestion or composting in small reactors in a semi-continuous manner. The same volume as the feeding volume was taken out daily and stored at -20 degrees C. Sample preparation for the bioassays was done by extraction using organic solvents, followed by clean up with silica gel or sulphuric acid, yielding two fractions. The fractions were dissolved in DMSO and tested in the bioassays. The dioxin-like activity was measured using the DR-CALUX assay with transfected H4IIE rat hepatoma pGudluc cells and an EROD induction assay with RTL-W1 rainbow trout liver cells. RESULTS AND DISCUSSION: The bioassays showed that the sludge contained AhR agonists at levels of TCDD equivalents (TEQs) higher than other sludge types in Sweden. In addition, the TEQ values for the acid resistant fractions increased considerably after anaerobic digestion, resulting in an apparent formation of acid resistant TEQs in the anaerobic reactors. Similar results have been reported from studies of fermented household waste. There was a large difference in effects between the two bioassays, with higher TEQ levels in the RTL-W1 EROD assay than in the DR-CALUX assay. This is possibly due to a more rapid metabolism in rat hepatocytes than in trout hepatocytes or to differences in sensitivities for the AhR agonists in the sludge. It was also demonstrated by GC/FID analysis that the sludge contained high concentrations of nitroaromatics. It is suggested that nitroaromatic metabolites, such as aromatic amines and nitroanilines, are possible candidates for the observed bioassay effects. It was also found that the AhR agonists in the sludge samples were volatile. CONCLUSIONS: The sludge contained fairly high concentrations of volatile AhR agonists. The increase of acid resistant AhR agonist after anaerobic digestion warrants further investigations of the chemical and toxic properties of these compounds and of the mechanisms behind this observation. RECOMMENDATION AND OUTLOOK: This study has pointed out the benefits of using different types of mechanism-specific bioassays when evaluating the change in toxicity by sludge treatment, in which measurement of dioxin-like activity can be a valuable tool. In order to study the recalcitrant properties of the compounds in the sludge using the DR-CALUX assay, the exposure time can be varied between 6 and 24 hours. The properties of the acid-resistant AhR agonists formed in the anaerobic treatment have to be investigated in order to choose the most appropriate method for sludge management.     

农业蔬菜废物处理方法研究进展和探讨

目前我国农业蔬菜废物污染问题正日益加重 ,蔬菜废物和其他固体废物相比具有高含水率、高营养成分和基本无毒害的特性 ,适宜于单独收集处理。本文介绍了国内外蔬菜废物处理方法的研究进展 ,包括好氧堆肥法、厌氧消化法、好氧 -厌氧联合处理法 ,并对这些方法的适用条件进行了论述。同时 ,探讨了接种微生物自然堆沤法的初步研究结果     

碳氮磷比例失调城市污水的同步脱氮除磷

为解决现行同步脱氮除磷工艺处理南方地区碳、氮、磷比例失调城市污水中,因C/N、C/P偏低,碳源不足而降低脱氮除磷效率的难题,试验以碳源偏低的广州市城市污水为研究对象,采用厌氧/好氧交替运行的SBR系统,通过对厌氧、好氧时段的合理调控,在无需额外添加碳源的条件下,有机物、氨氮、总氮和总磷的平均去除率分别可达90%、72%、41%和99%,不仅能使有机物和氮的出水指标达到国家排放标准,而且总磷出水浓度能达0.5 mg/L以下。通过进一步分析同步高效脱氮除磷的影响因素和控制条件,得出合理污泥龄的控制是实现同步脱氮除磷的关键,厌氧/好氧交替运行的方式不仅强化了磷的释放和吸收,而且降低了碳源偏低和硝酸盐对同步脱氮除磷影响的结论。     

预处理对城市固体有机垃圾厌氧发酵的影响

对近年来城市固体有机垃圾厌氧消化的各种预处理技术和发展趋势进行了综合分析和评述.研究认为,通过预处理能够改善城市固体有机物的物化性质,提高微生物对难降解有机物的降解,优化垃圾的厌氧消化过程.     

糖蜜酒精废水厌氧可生化性实验研究

采用自制的球形反应器对糖蜜酒精废水进行厌氧可生化性研究.实验持续了40 d,CODcr从38 652 mg·L-1下降到6 094 mg·L-1,总去除率达84.23%.说明糖蜜酒精废水的厌氧可生化性较好;硫酸盐浓度由最初的3 860 mg·L-1下降到470 mg·L-1,去除率为87.82%.同时,有机污染物的去除高峰期比其硫酸盐延迟了2～4 d,说明可以通过控制运行反应条件和参数,对该废水采用两相厌氧处理工艺,在产酸相提前去除大部分的硫酸盐,减弱高浓度硫酸盐对厌氧反应的抑制作用.     

啤酒生产废水处理设计及运行研究

分析了年产15万t啤酒的生产废水情况,介绍了采用IC厌氧反应器-一体化氧化沟处理该生产废水(7 200 m3/d)的工艺路线和主要设计参数,讨论了废水处理系统的运行情况.其中IC厌氧反应器的HRT为8 h,运行温度为35～37 ℃;一体化氧化沟包括氧化沟段和沉淀池段,总尺寸为40 m×24 m×6 m.IC厌氧反应器COD容积负荷在7.78 kg/(m3·d)时,COD去除率为84%左右.整套废水处理系统的COD总去除率为98%左右,出水COD小于80 mg/L.厌氧所产生的沼气可用于废水的升温.     

好氧预处理农业草类废物的BMP分析和动力学研究

农业草类废物既是一种废弃物，也是一种资源，由于其富含有机质，可通过厌氧生物降解产生沼气。本文研究了农业草类废物的好氧预处理对其固含量成分，生物沼气产生潜力（ＢＭＰ），甲烷浓度，产气速率的影响进行了研究；并计算了作为一级反应的反应速率常数，其结果表明模型与实验值一致性较好。     

污泥与高浓度有机废物厌氧消化反应中的产气量

研究了高温／中温两相厌氧消化反应器系用以同时处理污泥与不同高浓度有机废物时产气及产甲烷的变化特性。结果表明，气体及甲烷主要是在第二段的中温消化反应器内产生。当中温消化反应器的有机负荷ＶＳ为１．６５￣３．１０ｋｇ／ｍ＾３ｄ时，稳态条件下的平均产气量为１．９５８￣４．０２０ｍ＾３／ｄ，气体中甲烷的平均组成为６５％￣７３％，甲烷的比产率为０．３９７￣０．５１１ｍ＾３／ｋｇＶＳ。