生物废水处理系统的细胞自动机模型

建立了活性污泥处理生物废水的细胞自动机模型,对活性污泥生物量与有机物浓度动态进行了研究,提出了计算活性污泥回流循环比的方法.结果表明,在Moore邻居模型下废水达标排放所需时间较Von. Neumann邻居模型少,不同生长阶段的微生物浓度波动具有时滞性.稳定期有机物浓度和生物量不受活性污泥初始浓度的影响.活性污泥处理生物废水的细胞自动机模型有助于为污水处理提供理论依据.     

Formation of nitrifying biofilms on small suspended particles in airlift reactors

For a stable and reliable operation of a BAS-reactor a high, active biomass concentration is required with mainly biofilm-covered carriers. The effect of reactor conditions on the formation of nitrifying biofilms in BAS-reactors was investigated in this article. A start-up strategy to obtain predominantly biofilm-covered carriers, based on the balancing of detachment and a biomass production per carrier surface area, proved tp be very successful. The amount of biomass and the fraction of covered carrier were high and development of nitrification activity was fast, leading to a volumetric conversion of 5 kg(N) . m(-3) . d(-1) at a hydraulic retention time of 1h. A 1-week, continuous inoculation with suspended purely nitrifying microorganisms resulted in a swift start-up compared with batch addition of a small number of biofilms with some nitrification activity. The development of nitrifying biofilms was very similar to the formation of heterotrophic biofilms. In contrast to heterotrophic bio-films, the diameter of nitrifying biofilms increased during start-up. The detachment rate from nitrifying biofilms decreased with lower concentrations of bare carrier, in a fashion comparable with heterotrophic biofilms, but the nitrifying biofilms were much more robust and resistant. Standard diffusion theory combined with reaction kinetics are capable of predicting the activity and conversion of biofilms on small suspended particles. (c) 1995 John Wiley & Sons Inc.     

Co-composting of hair waste from the tanning industry with de-inking and municipal wastewater sludges

Production of waste hair in the leather manufacturing industry is increasing every year due to the adoption of hair-save unhairing techniques, leaving the tanners with the problem of coping with yet another solid by-product. Numerous potential strategies for hair utilisation have been proposed. However, the use of hair waste as agricultural fertiliser is one of its most promising applications due to the high nitrogen content of hair. Agricultural value of hair can be increased by composting. This paper deals with the composting of hair from the unhairing of bovine hide. Results indicated that hair cannot be either composted on its own or co-composted with de-inking sludge, a chemical complementary co-substrate. However, good results were obtained when co-composted with raw sludge from a municipal wastewater treatment plant at hair:raw sludge weight ratios 1:1, 1:2 and, 1:4 in lab scale and pilot plant scale composters. In all cases, a more stable product was achieved at the end of the process. Composting in the pilot plant composter was effectively monitored using Static Respiration Indices determined at process temperature at sampling (SRI _T ) and at 37°C (SRI₃₇). Notably, SRI _T values were more sensitive to changes in the biological activity. In contrast, Respiratory Quotient (RQ) values were not adequate to follow the development of the process.     

Correlation between bacterial indicators and bacteriophages in sewage and sludge

The use of bacteriophages as potential indicators of faecal pollution has recently been studied. The correlation of the number of bacterial indicators and the presence of three groups of bacteriophages, namely somatic coliphages (SOMCPH), F-RNA-specific phages (FRNAPH) and phages of Bacteroides fragilis (BFRPH), in raw and treated wastewater and sludge is presented in this study. Raw and treated wastewater and sewage sludge samples from two wastewater treatment plants in Athens were collected on a monthly basis, over a 2-year period, and analysed for total coliforms, Escherichia coli, intestinal enterococci and the three groups of bacteriophages. A clear correlation between the number of bacterial indicators and the presence of bacteriophages was observed. SOMCPH may be used as additional indicators, because of their high densities and resistance to various treatment steps.     

白曲霉工程菌TR12循环转化酒精废液研究

在含固体残渣8％的酒精废液中,加入尿素2g／L、玉米浆2mL／L,经接种白曲霉基因工程菌TRl2菌株,在32℃摇床培养70h后,可获得含糖化酶246U／mL和耐酸性α-淀粉酶13．42U／mL的转化液。转化液直接循环利用于无蒸煮酒精发酵配料工序,不仅不影响酒精生产的产量和质量,而且能有效地减轻环境污染压力,节约水资源,降低生产成本。     

具超强汞富集能力基因工程菌生长情况的研究

对具超强汞富集能力的基因工程菌在重金属汞离子存在的水体中的生长状况进行了研究。实验所采用的基因工程菌由于外源基因的表达而对Hg^2 产生了一定的耐受力,而且这种耐受力经IPTG诱导后还能得到进一步的增强,耐受能力从Hg^2 浓度5mg／L提高到15mg／L。IPTG加入的时机对菌体的生长和耐受力的有效诱导是重要的。一般在OD600为0．5～0．8时加入,且加入后还应保证2h左右的诱导时间。实验结果还表明菌体在生长过程中对碳源的要求很低。     

High rate anaerobic digestion of a petrochemical wastewater using biomass support particles

Anaerobic digestion of wastewater from a dimethyl terephthalate plant was studied in continuously stirred tank reactors with plastic net biomass support particles (BSP) at a level of 20% (v/v). The experimental results showed that the BSP system could treat the wastewater at a hydraulic retention time as low as 1.5 d, organic loading as high as 20 kg COD/m3/d and at acidic feed pH as low as 4.5 with 95% COD reduction and biogas production of about 8l/l/d, while the control system without support particles could not treat the wastewater above a 5-d hydraulic retention time, 5 kg COD/m3/d organic loading and a feed pH of 6.0. Thus, augmentation of BSP upgraded the performance of the conventional suspended growth system to an equivalent level to advanced reactors.     

Biodegradation of N-Methylmorpholine-N-oxide

N-Methylmorpholine-N-oxide (NMMO) is capable of dissolving cellulose without any further addition of chemicals. The solution can be used to produce cellulosic staple fibres by pressing it through spinning jets into an aqueous spinning bath. Because of results from conventional biodegradation tests using non-adapted activated sludge, the solvent is generally considered being persistent. The object of the described work was to show, whether and how activated sludge can be adapted to N-methylmorpholine-N-oxide and whether it is possible to purify NMMO-containing wastewaters in conventional wastewater treatment plants. The experiments showed that the sludge can be adapted within about 15–20 days. Adapted sludge can degrade the substance itself and its most important metabolites to concentrations below their detection levels and retain this ability even during limited periods without solvent being present in the wastewater. The main requirement for a successful adaptation is a high sludge age. The degradation takes place in several steps. First, NMMO is reduced to N-methylmorpholine. The next step is a demethylation of N-methylmorpholine to morpholine. This step is crucial for the adaptation process. Once morpholine has been formed, the adaptation proceeds very quickly until none of the substances in question can be detected any longer. So the next step must be the cleavage of the morpholine ring structure.     

两种不同根系类型湿地植物的根系生长

实验设计了一个水培系统,利用生活污水培养,对4种“须根型”植物美人蕉、风车草、象草和香根草和4种根茎型植物菖蒲、水鬼蕉、芦苇和水烛的根系生长进行比较研究。该系统由用于盛污水的塑料桶（顶部直径36．5cm,底部直径30．Ocm,高34．5cm）和用于固定植物于水面的泡沫板构成。每桶种植1株植物,每种种5株。水培至10周时,须根型植物的平均根数达到1349条／株,而根茎型植物的平均根数只有549条／株。实验结束（水培第21周）时,须根型植物的平均根生物量为11．3g／株,根茎型植物的平均根生物量为7．4g／株。须根型植物根系中,d〈1mm的细根生物量占根系总生物量的51．9％,而根茎型植物d〈1mm的细根的生物量只占25．1％。根茎型植物的根生物量与地上生物量的比值为0．2,显著高于须根型湿地植物（0．1）。须根型湿地植物的根系表面积（6933cm^2／株）极显著地高于根茎型湿地植物（1897cm^2／株）。根茎型湿地植物根的平均寿命（46．6d）较须根型湿地植物根的平均寿命（34．8d）长。美人蕉的平均根数达1871条／株,根表面积达到22832cm^2／株,远较其他种高。     

Treatment of coal gasification wastewater by a two-continuous UASB system with step-feed for COD and phenols removal

A two-continuous mesophilic (37 ± 2 °C) UASB system with step-feed was investigated as an attractive optimization strategy for enhancing COD and total phenols removal of the system and improving aerobic biodegradability of real coal gasification wastewater. Through the step-feed period, the maximum removal efficiencies of COD and total phenols reached 55-60% and 58-63% respectively in the system, at an influent flow distribution ratio of 0.2 and influent COD concentration of 2500 mg/L; the corresponding efficiencies were at low levels of 45-50% and 43-50% respectively at total HRT of 48 h during the single-feed period. The maximum specific methanogenic activity and substrate utilization rate were 592 ± 16 mg COD-CH₄/(gVSS d) and 89 ± 12 mg phenol/(gVSS d) during the step-feed operation. After the anaerobic digestion with step-feed, the aerobic effluent COD concentration decreased from 270 ± 9 to 215 ± 10 mg/L. The results suggested that step-feed enhanced the degradation of refractory organics in the second reactor.