Methane Emissions from Aerated Zones in a Full-Scale Nitrifying Activated Sludge Treatment Plant

This study was performed to evaluate the ability of white-rot fungi to decolorize dye effluents. A total of 222 isolates of white-rot fungi were initially investigated to assess their ability to decolorize chemically different synthetic dyes in solid medium, resulting in selection of 25 isolates including four isolates of Berkandera adusta, five isolates of Ceriporia lacerata, three isolates of Irpex lacteus, one isolate of Perenniporia fraxinea, ten isolates of Phanerochaete spp., one isolate of Phlebia radiata, and one isolate of Porostereum spadiceum. Of the 25 isolates, B. adusta KUC9065, C. lacerata KUC8090, P. calotricha KUC8003, and P. spadiceum KUC8602 were finally selected on the basis of their ability to decolorize synthetic dyes in liquid medium, and were used to decolorize industrial effluents. B. adusta KUC9065 increased the transmittance of visible light by 71–92 %. Decolorization of wastewater by B. adusta KUC9065 was probably caused by the lignin-modifying enzymes produced by the fungus. In addition, the acute toxicity to Daphnia magna decreased from 2.5 to 2.1 and from 3.5 to 2.6 toxic units over 24 and 48 h, respectively.     

Microfauna Community as an Indicator of Effluent Quality and Operational Parameters in an Activated Sludge System for Treating Piggery Wastewater

In order to study the potential use of microfauna as an indicator of effluent quality and operational parameters in an activated sludge system for treating piggery wastewater, an experimental sequencing batch reactor was set up and evaluated by biological and physical–chemical analyses for 12 months. Results show that microfauna (and specifically ciliate protozoa) are a good parameter for assessing effluent quality in terms of both chemical oxygen demand (COD) and ammonia and for assessing the organic and nitrogen load of the system. Specifically, the abundance of ciliates decreases from 20,000 individuals·mL^?1 to ca. 2,500 individuals·mL^?1 and from ca. 10,000 individuals mL^?1 to ca. 200 individuals mL^?1 when effluent concentration is between 550 and 750 mg L^?1 and above 100 mg L^?1 to the COD and ammonia concentrations, respectively. Furthermore, microfauna abundance is reduced from ca. 18,000 individuals mL^?1 (organic load between 0.1 and 0.2 mg COD mg total suspended solids (TSS)^?1 day^?1) to ca. 500 individuals mL^?1 (organic load between 0.3 and 04 mg COD mg TSS^?1 day^?1). Microfauna abundance also decreases as nitrogen loading increases. Nitrogen loading in the range of 5–60 mg NH₄–N g TSS^?1 day^?1 does not have any significant effect on microfauna abundance. However, ammonia loading from 60 to 120 mg NH₄–N g TSS^?1 day^?1 reduces microfauna abundance ca. 6-fold. Ciliate protozoa were the largest microfauna group during the whole period of study, representing ca. 75% of the total microfauna abundance. The largest group in the ciliate community was that of the free-swimming ciliates. This was followed by the group of attached and crawling ciliates. Specifically, the dominant ciliate species during the whole study period were Uronema nigricans, Vorticella microstoma-complex, Epistylis coronata, and Acineria uncinata.     

Composting of Yard Waste and Wastewater Treatment Plant Sludge Mixtures

Composting of yard waste and sludge/yard waste mixtures was investigated during laboratory and field testing. A strong correlation between moisture content and windrow peak temperatures was observed. Odors were detected at cocomposting windrows when temperatures exceeded 54°C. The sludge to yard waste mixture ratio was found to affect resulting compost particle size and, consequently, oxygen transport. Compost quality was excellent, with pesticides below detection level and low concentrations of heavy metals.     

Comparison of Activated Sludge Technologies by Particle Size Analysis

This paper analyses the influence of activated sludge technologies on the Particle Size Distribution (PSD) of urban wastewater treatment plants operating under real conditions. The activated sludge treatment systems selected for the analysis are the most widely used in wastewater treatment installations: (a) double step activated sludge, (b) medium load activated sludge, (c) prolonged aeration, and (d) membrane bioreactors The main quality parameters (suspended solids, turbidity, and COD) and PSD in the influent and effluent of each different activated sludge treatment were analyzed during 1?year. The PSD was fitted using the power law ( $ n\left( {{d_{\text{P}}}} \right) = \frac{{\partial {\text{N}}\left( {{d_{\text{p}}}} \right)}}{{\partial {d_{\text{p}}}}} = A \cdot d_{\text{p}}^{{ - b \cdot {\text{Log}}\left( {{d_{\text{p}}}} \right)}} $ ) obtaining coefficients A and b to define the particle distribution. Mathematical correlations between this coefficients and the rest of parameters studied were found $ \left( {\matrix{ {{\text{SS}} = {0}{.0126} \cdot {A^{{{0}{.781}}}},} &{{\text{Turbidity}} = 15.5814 + 1.164 \cdot {{10}^3} \cdot A{,}} &{{\text{COD}} = \frac{{1}}{{{0}{.0133} + \cdot \frac{{{49}{.85}}}{\text{A}}}}} \\ }<!end array> } \right) $ . The relation with the average particle size by mass was also found, ( $ {d_{\text{pma}}} = - 11.6502 + \frac{{50.4265}}{b} $ ). Moreover, a relation between PSD and the particle elimination efficiency of the secondary treatment was study, ( $ \eta = 0.1434 - \frac{{0.5602}}{{{A_{\text{rel}}}}} + \frac{{0.7490}}{{{b_{\text{rel}}}}} $ ). Finally, the particulate matter nature was assessed by SEM-EDX. It can be concluded that membrane bioreactor is the technology that produces the best water quality effluent due to physic process of particle separation by ultrafiltration membrane technology.     

浅谈污水土地处理系统

污水土地处理系统是一种基于土壤-生物作用的污水净化技术,其投资少、建设运营成本低,日益受到全球的关注。本文概述了污水土地处理系统的类型、净化机理、优势,讨论了其存在的问题及改进建议,并对污水土地处理系统在我国的应用前景做出了展望。     

Adsorption of Natural Estrogens and Their Conjugates by Activated Sludge

Adsorption to biomass is a key mechanism which results in the elimination of natural estrogens and their conjugates from sewage. Freundlich model showed that the adsorption capacities of estrone and 17β-estradiol to activated sludge were the highest at neutral pH. The lower capacities at pH 2 and 11.5 could be due to the competition of sludge adsorption sites by cations or electrostatic repulsion from particles of similar charges. The lowest adsorption capacity at pH 11.5 was attributable to electrostatic repulsion, and the highest capacity at pH 2 might be due to the increased sulfate adsorbability. For estrogen conjugates such as estrone-3-sulfate and 17β-estradiol-3-sulfate, adsorption performances were similar at pH 5, 7, and 9. It was observed that mean values of log K _D were 2.78, 2.61, 1.67, and 1.94 l kg TSS^?1; log K _OM were 2.96, 2.79, 1.77, and 2.04 l kg VSS^?1 and those of log K _OC were 3.31, 3.12, 2.21, and 2.46 l kg OC^?1 for estrone, 17β-estradiol, estrone-3-sulfate, and 17β-estradiol-3-sulfate, respectively.     

Influence of Integrated Membrane Treatment on the Phytotoxicity of Wastewater from the Coke Industry

In this paper, coke wastewater that had passed through biological and integrated membrane processes (filtration on sand bed—reverse osmosis) was chosen to assess the phytotoxicity of selected industrial wastewater with regard to the test plant—Vicia faba. An innovative research technique in vitro test was conducted in a large scale phytothrone chamber on two matrices: cotton and Murashige and Skoog Basal Medium (MSBM). The toxicity of wastewater was evaluated for samples: (1) treated in the treatment plant by biological processes, (2) filtrated through a sand bed and filtrated (3) reverse osmosis (RO) membrane. The results showed that there is a noticeable correlation between increasing concentrations of wastewater and seed germination of the test plant. Although the wastewater collected from the coke plant was treated biologically, it showed very high levels of germination inhibition (90–98% for cotton matrix and 92–100% for MSBM matrix) and strong toxic effects. The wastewater collected from the coke plant showed a significantly greater phytotoxic effect compared with those obtained from the effluent treated on a sand bed and in RO. However, wastewater, even after treatment on a sand bed (reduction of COD—39%, TN—46%, TOC—42%, TC—47%, SS—50%, 16PAHs—53%), was still toxic and germination inhibition was in the range of 24–48% for the cotton matrix and 14–54% for the MSBM matrix. The toxicity of wastewater treated in the membrane process was the lowest (reduction of COD—85%, TN—95%, TOC—85%, TC—86%, SS—98%, 16PAHs—67%). The germination inhibition was in the range of 4–10% for the cotton matrix and 2–12% for the MSBM matrix. These samples are classified as non-toxic or slightly toxic to the model plant. The present study highlights the necessity of monitoring not only the basic physical and chemical indicators (including the level of toxic substances as PAHs), but also their effect on the test organisms in wastewater samples.     

腐殖酸与活性污泥对污染土壤联合修复研究

采用正交试验的方法,研究了表面活性剂溶出和微生物降解联合作用对重金属铜、锌、铅和多环芳烃菲、萘、芘人工老化污染土壤的修复效率。选择腐殖酸为表面活性剂,强化微生物对有机污染物的降解性能,将高效降解菌的降解能力有效地发挥出来;用驯化的活性污泥为土壤生物修复剂,强化腐殖酸对重金属的洗提作用,旨在降低重金属和多环芳烃在土壤中的污染作用,提高修复效率。结果表明,接种2.0%活性污泥,温度为35℃,pH值为6.5,腐殖酸加入量为5mg/g的土壤为最佳修复条件,在此条件下菲、萘、芘的总修复率分别为73.4%,80.5%和68.2%;重金属离子Cu2+,Zn2+,Pb3+的总修复率分别为75.5%,64.2%和71.7%。添加腐殖酸和驯化活性污泥可明显提高土壤中重金属和多环芳烃的修复效率,表明化学溶出与生物降解同时作用于复合污染土壤具有较好的协同作用。     

Magnetic Separation of Ferrite Sludge from a Wastewater Purification Process

The purpose of this research was to evaluate the apparent molecular weight distribution of dissolved organic matter (DOM) from pig slurry and the binding ability of its fractions toward copper (Cu²⁺) ions. In addition, the binding ability (maximum complexing capacity – MCC) of the DOM was compared with that of humic (HA) and fulvic (FA) acids from a clay-loam soil. The study was performed using Cu²⁺ ions since this metal is widely used as a supplement in pig diets and, consequently, is present in pig slurry. The techniques adopted were gel filtration chromatography (GFC) and dialysis. GFC showed that the DOM from pig slurry is mainly composed of a fraction with an apparent molecular weight higher than 5000 Da and the copper naturally present in the slurry is completely complexed by this fraction. The dialysis procedure enabled MCC to be determined. The MCC of pig slurry DOM and soil HA, which contained a similar concentration of carboxylic groups, were analogous, while MCC of soil FA, which contained double the concentration of carboxylic groups, was higher.     

Long-Term Effects of Tourmaline on Nitrogen Removal from Wastewater and Bacterial Community Shift in Activated Sludge at Low Temperatures

In this study, the long-term effects of ultrafine tourmaline particles (UTPs) on the removal of nitrogen in wastewater, activated sludge viability and microbial population dynamics at low temperatures were investigated. Although there was no significant effect on the effluent concentrations of nitrogen after long-term exposure to 1 g/L UTPs at low temperatures, the oxidation rate of NH₄⁺-N and the accumulation rate of NO₂^?-N increased and the formation rate of NO₃^?-N decreased during the aerobic phase of sequencing batch reactors. However, long-term exposure to 1 g/L UTPs did not significantly affect the microbial community richness and the community diversity of activated sludge at low temperatures. The mechanism of tourmaline was studied by assessing the dominant functional species involved in biological nitrogen removal from wastewater. It was found that 1 g/L UTPs increased the removal rate of nitrogen by reducing the relative abundance of nitrite oxidizing bacteria and increasing the relative abundance of ammonia oxidizing bacteria after long-term operation at low temperatures.     

Activated Sludge Acclimation for Hydrophobic VOC Removal in a Two-Phase Partitioning Reactor

The effect of activated sludge acclimation on the biodegradation of toluene and dimethyldisulphide (DMDS) in the presence of a non-aqueous phase liquid, polydimethylsiloxane (PDMS), in a two-phase partitioning bioreactor was characterized. The influence of the presence of PDMS, at a ratio of 25% (v/v), and acclimation of activated sludge on two hydrophobic VOC biodegradation was studied. Activated sludge were acclimated to each VOC and in the presence of the non-aqueous phase liquid, namely in the emulsion of PDMS in water. Using acclimated cells, 97.9% and 108.7% improvement of the mean biodegradation rates were recorded for toluene and DMDS, respectively, if compared to the values recorded in the absence of acclimation. While and in agreement with the lower solubility in water of DMDS if compared to toluene, a most significant effect of PDMS addition on the rate of DMDS removal was recorded, 87.0% and 153.6% for toluene and DMDS, respectively. In addition and if both biomass acclimation and PDMS addition were considered, overall improvements of the removal rates were 204% and 338% for toluene and DMDS.     

Design and Modeling of Post-Denitrification Single-Sludge Activated Sludge Processes

A step-by-step design approach for sizing oxic/anoxic single- sludge activated sludge systems is presented. A computer model utilizing a Lotus 1–2–3 spreadsheet was also developed which simulates the post- denitrification single-sludge activated sludge process. The biokinetic equations developed by Lawrence and McCarty are utilized in the model. The model was calibrated using data from a full-scale, modified pure oxygen activated sludge process operating in the oxic/anoxic mode. Two- tailed, paired comparison student ‘t-tests’ performed on effluent BOD₅, SS, TKN, NH₃-N, NO^- ₃-N, and TN indicated there was no significant difference between the actual effluent values and that predicted by the model at a 99 percent confidence level.     

Scale of Small Particle Population in Activated Sludge Flocs

The light scattering method is a valuable tool for accessing particle size and structure mainly due to fast and the nonintrusive nature of the measurement. The method is based on a scattered intensity pattern and depends on particle volume, particle morphology, the light wavelength and the scattering angle. The light scattering model, for particles characterised by a fractal structure, is enabled with the use of the Rayleigh-Gans-Debye theory under constrained assumptions. The range of validity of the Rayleigh-Gans-Debye is limited when primary particles constituting aggregate have a size close to the wavelength. In this work, a range of particle sizes was characterised in order to achieve a better understanding of the relationship between flocs size and its fractal dimension. Hence, the width of the power law regime is discussed. What is more, a specific fractal dimension value of activated sludge flocs was found for each of the analysed wastewater treatment plant, which suggests that the spatial structure of suspensions constituting the activated sludge is an individual characteristic of each treatment facility. It has been shown that activated sludge consists of microflocs from the range of 1–10 μm, which constitute approximately 90% of all the population.     

Effects of Nitrolotriacetic Acid-Copper Complexes on Activated Sludge Process

Effects of nitrilotriacetic acid (NTA), copper ion (Cu2+) and their complexes on the efficiency of activated sludge process were evaluated by determining the changes in physical and chemical parameters in a laboratory-scale unit. Primary effects of these toxicants on microorganisms in the activated sludge process were also evaluated by determining the change of in vivo dehydrogenase activity. The presence of 1 mg L-1 or higher of Cu2+ significantly affected the activated sludge process. Nitrification in the activated sludge process was more sensitive to the inhibition of Cu2+. The presence of NTA, as high as 20 mg L-1, did not significantly affect the activated sludge process. Moreover, in the presence of 20 mg L-1 of NTA, the toxicity of Cu2+ on the activated sludge process was significantly reduced.     

Zirconium-Modified Activated Sludge as a Low-Cost Adsorbent for Phosphate Removal in Aqueous Solution

A highly effective zirconium-modified activated sludge (Zr(IV)-AS) adsorbent was prepared from activated sludge and applied to remove phosphate from aqueous solutions by batch and column experiments. Characterized results revealed that zirconium was successfully loaded onto the activated sludge (AS), and the specific surface area and pore volume were substantially improved after zirconium loading on the AS. Zr(IV)-AS exhibited a high adsorption affinity for phosphate and the maximum adsorption amount was 27.55 mg P·g^?1 at 25 °C. Adsorption isotherms of phosphate could be described by the Langmuir model, and the adsorption kinetics were well described by the pseudo-second-order model. Phosphate adsorption on Zr(IV)-AS increased monotonically with decreasing solution pH. The presence of SO₄^2? in water resulted in slightly decreased phosphate adsorption on the adsorbent even at a high concentration (25 mmol/L), and a greater influence of HCO₃^? on adsorption could be ascribed to the increased solution pH with the addition of the HCO₃^?. Column adsorption experimental results showed that the adsorbent has excellent phosphate adsorption properties and that the effluent can meet the requirement of phosphorus in the national wastewater discharge standard of China. Phosphate-saturated Zr(IV)-AS can be effectively desorbed in 0.1 mol L^?1 NaOH solution, and the regenerated adsorbent still possessed the high capacity. The adsorption between the adsorbent and the phosphate is due to the electrostatic interaction and anionic exchange at the surface of the Zr(IV)-AS. Furthermore, this approach provides a possibility of treating wastewater with waste and has the potential for industrial applications for the removal of phosphate from wastewater.     

Oxygen Transfer and Industrial Wastewater Treatment Efficiency of a Vertically Moving Biofilm System

A vertically moving biofilm system (VMBS) was developed to treat wastewater. In this system, the biofilm grows on a biofilm module consisting of plastic media that is vertically and repeatedly moved up into the air and down into the water. The objectives of this study were to investigate the oxygen transfer efficiency and industrial wastewater treatment performance of the VMBS. The oxygen transfer coefficient (K _L a) depended on the movement frequency (n) of the biofilm module and was proportional to n ^1.67. K _L a values measured were within the range of 0.0001 to 0.0027 s^-1. The VMBS exhibited good carbonaceous removal when treating industrial wastewater produced in a factory manufacturing synthetic fibres. Removal efficiency of filtered chemical oxygen demand (COD) and biological oxygen demand (BOD₅) was up to 93.2 and 97.9%, respectively. The volumetric removal rates of filtered COD and BOD₅ reached 1320 g COD m^-3 day^-1 and 700 g BOD₅ m^-3 day^-1. The areal organic removal rates, based on the surface area of the biofilm substrata, were 16 g BOD₅ m^-2 day^-1 and 39 g COD m^-2 day^-1. No clogging occurred during the experiment. The mean areal biofilm mass increased with increasing the mean areal BOD₅ removal rate. The new biofilm process has such advantages as high carbonaceous oxidation, energy saving, simpleconstruction and easy operation for industrial wastewater treatment.     

互花米草厌氧发酵渣活性炭处理含镉废水的研究

采用静态吸附法,进行磷酸活化法不同剂料质量比（0.5～3.0）及活化温度（400～700℃）条件下制备的互花米草厌氧发酵渣活性炭对镉的吸附性能研究,考察不同初始浓度条件下活性炭对镉的平衡吸附量,旨在以吸附法治理含镉废水,探索吸附机理、影响因素、除镉吸附剂的最佳制备条件以及活性炭物化性质对镉吸附性能的影响。结果表明,镉的吸附性能与活性炭的制备条件有关,随着活化温度的升高,镉的吸附量逐渐增大,主要是因为高温条件下活性炭表面PO34-充当活性位点,促进镉的吸附。当剂料质量比为1.0,活化温度为700℃时,制备出的活性炭对镉的吸附性能最好,其最大吸附量可达38.91mg·g^-1,远远高于商业活性炭。镉的吸附量随着溶液初始浓度的增加而增大,吸附等温线符合Langmuir方程。溶液pH和活性炭表面化学性质是决定镉吸附量大小的决定性因素,当溶液pH在2～4时,各活性炭对镉的吸附能力随pH的增加而增加。本文为含镉废水的处理提供了一种低价高效的方法。     

新型高效反应器组合系统处理奶牛养殖场废水试验研究

选择一种新型高效反应器系统对奶牛养殖场废水进行处理试验研究,这种反应器系统主要包括两级组合生物巢厌氧反应器和砂式沼液处理池。试验结果表明,该系统处理奶牛养殖废水速度快,两级组合生物巢厌氧反应器水力停留时间（HRT）仅为15h,处理效率高,砂式沼液处理池结构简单,对生物巢厌氧反应器出水处理效果好。该新型高效反应器组合系统对化学需氧量（COD）、生化需氧量（BOD）、氨氮（NH3-N）和总固体悬浮物（TSS）的平均去除率分别为97.6%、98.2%、81.3%和98.1%,出水体积质量平均值分别为89.0、27.1、15.7mg·L^-1和64.9mg·L^-1,满足国家二级排放标准。