添加造纸白泥对猪场废水厌氧消化液中氮磷回收的影响

以造纸废弃物白泥作为pH调节剂,利用MAP沉淀法回收厌氧消化液中的氮磷,并采用曝气的方式提高消化液pH值和造纸白泥的溶解性,研究了造纸白泥的添加量和曝气时间对厌氧消化液中氮、磷回收效果的影响,并考察了曝气过程中pH、COD、PO34--P、NH3-N、Mg2＋、Ca2＋的变化规律。结果表明造纸白泥的添加量为8g.L-1,曝气时间为120min时,PO34--P和NH3-N的回收率分别达到98和59,出水的PO34--P和NH3-N浓度分别为0.98mg.L-1和60.66mg.L-1,均达到了《畜禽养殖业污染物排放标准》（GB18596—2001）的要求,同时,COD的去除率为45;如果仅用曝气方式处理,120min后PO34--P和NH3-N的回收率仅分别为66和41,均未达到排放标准要求。可见,与仅用曝气方式处理相比,添加造纸白泥协同曝气对厌氧消化液中氮磷的回收有明显的效果。     

猪场废水厌氧消化液后处理技术研究及工程应用

猪场废水经过厌氧消化后，可生化性变差，BOD₅/COD仅为0.19，并且碳、氮倒置，比例严重失调，给后续好氧处理带来很大困难。采用序批式活性污泥法(SBR)工艺直接处理厌氧消化液，污染物的去除效果很差，COD仅去除8.31%，NH₃-N去除78.7％。通过改善厌氧消化液的可生化性和培养高效脱氮菌种等措施，COD、NH₃-N去除率改善显著，COD、BOD₅与SS的去除分别达到89.6%～93.4%、97.9%，95.6%，特别是对NH₃-N，达到了99%以上去除效率。将实验室结果应用于实际工程，也取得了好的效果，工程上SBR系统对猪场废水厌氧消化液的COD去除90%左右，出水COD基本上在300 mg/L以下。NH₃-N去除率大于99%，出水NH₃-N小于10 mg/L。BOD₅去除率大于98%，出水BOD₅小于20 mg/L。TN去除率大于90%。     

Waste Activated Sludge as an Additive for Increment of Lime Sorption Capacity

Lime was physically blended with Waste Activated Sludge (W.A.S) in various proportions. These blends were hydrated, dried, ground, and sieved to size of utmost 200 μm. The sorbents were then used in fixed-bed reactor for dry desulfurization tests. It was found that the blends had higher sorption capacities than lime alone which means that W.A.S augmented lime's sorption capacity. Higher surface area and porosity of the blended sorbents compared to lime was the main cause of the improved sorption capacity, a conclusion supported by Brunauer–Emmett–Teller surface area analysis (surface area increment with sorption capacity) and scanning electron microscopy imaging (rough morphology being formed). This higher surface area and porosity was caused by pozzolanic reaction between lime and the alumina silicate constituents of W.A.S. The products of this reaction are high surface area, complex calcium alumina silicates.     

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.     

Quantification of Odours from Piggery Effluent Ponds using an Electronic Nose and an Artificial Neural Network

An Artificial Neural Network (ANN) and an electronic nose, AromaScan, were used to predict the piggery odour concentrations emanating from an effluent pond and to develop a confident, rapid, and cost-effective technique for odour measurement. Odour samples from five different piggery effluent ponds were analysed using the AromaScan and dynamic dilution olfactometry. The resulting sensor data were used to train the artificial neural network to correlate the responses to the odour concentrations measured by olfactometry. Effectiveness was evaluated through simulation with various pre-processing techniques and network architectures. The simulation results have shown that a two-layer back-propagation neural network, which has a tan-sigmoid transfer function in the hidden layer and a linear transfer function in the output layer, could be trained to predict piggery odour concentrations with high value of the correlation coefficient R of 0·984 under the best network performance. The results from the application of scaling and principal component analysis suggest that these techniques are necessary not only to avoid the failure of the network caused by saturation but also to enhance performance. An early stopping technique was shown to provide benefits to the network performance in terms of a decrease in computation time and overfitting. It was found that the optimal number of hidden neurons for the network was 20. Odour concentration of unknown samples were able to be predicted with significant accuracy.     

Impact of Water Quality Parameters on the Clogging of Vertical-Flow Constructed Wetlands Treating Urban Wastewater

Water, Air, &; Soil Pollution - In theory, biological and physical clogging, induced as a result of potentially excessive formation of biomass from degradation of pollutants and retention of...     

Chemical Evaluation of Sewage Sludge Composting as a Mature Indicator for Composting Process

Several chemical parameters were studied during a 100 daysperiod in order to identify parameters that can be used asindicators of compost maturity. One treatment was a mixture ofsewage sludge and sawdust (TS); another was a mixture of sewagesludge, pig manure and sawdust (TS-PM). The pH of water extractsincreased during the thermophilic phase and then decreased in twotreatments. While the electrical conductivity (EC) decreasedthroughout the composting time. The 4.99% in the change ofvolatile matter of TS-PM was higher than 1.73% in that of TS,at the same time, the change of organic carbon were 5.04% inTS-PM more than 3.82% of TS. Total nitrogen content in TS andTS-PM had a markedly increase tendence during composting, andthe change in TS-PM was very more obvious than in TS, soreduction of C/N ratio in TS-PM was higher than in TS, C/Nratio of TS-PM and TS was 14.39 and 18.57 in mature production,respectively. Carbon content in HA plus FA and HA in twocomposts decreased from 0 to 100 day, but carbon content of FAdecreased, so HA-C/FA-C ratio, HR, HI has a markedly increase inTS and TS-PM, and the parameters in TS-PM were higher than inTS. The points expressing maturity degree in TS-PM was more inTS. The nitrogen content of HA plus and HA showed a increasedtendence in TS and TS-PM, the change of nitrogen of thesefractions in TS-PM was higher than in TS, so C/N ratio of allfractions including HA plus FA, HA and FA, indicated a reductiontendence, and the refuction in FA was larger than in HA. E4/E6ratio of HA plus FA and HA decreased during composting, and one FA was increase. E4/E6 ratio of HA plus FA and HA in TS-PM wasvery smaller than in TS, HA in TS-PM was a larger molecular sizethan HA in TS. The changes of organic matter compositions incomposting: the crude fat and carbohydrates had a markedlyreduction and cellulose plus hemicellulose had a slight decrease;crude protein and lignin content in TS and TS-PM had an increasetendence.     

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.     

猪场废水生化处理工艺研究

针对猪场废水有机物、氮、磷含量高的特征，应用上流式厌氧污泥床(UASB)和序批处理反应器(SBR)相结合废水处理工艺，研究了不同水力负荷条件下对COD、BOD、氨氮去除率的影响。研究结果表明，在COD 2～8 kg/(m³·d)条件下，COD的去除率在60%～73%之间，效果较稳定；SBR在去除氨氮中效果十分明显，去除率达80%～95%。     

Leaf Chlorophyll Readings as an Indicator for Spinach Yield and Nutritional Quality with Different Nitrogen Fertilizer Applications

The objective of this study was to investigate the possibility of predicting the concentrations of total nitrogen (N), nitrate-nitrogen, and ascorbic acid in spinach (Spinacia oleracea) leaves using the pocket chlorophyll meter SPAD-502 (Minolta, Japan) in a pot experiment in a greenhouse. Spinach plants were grown in plastic pots filled with 0.5 kg of brown soil per pot with urea as N fertilizer at 0, 30, 60, 120, and 240 mg N/kg soil. SPAD readings of the two uppermost fully expanded leaves were recorded 18, 25, and 32 d after sowing and at harvesting (34 d). Dry-matter biomass and total N concentrations in leaves and roots, and NO₃-N, and ascorbic acid concentrations in leaves, were measured after harvesting. SPAD readings showed continuous reduction with increasing growth period irrespective of N applications. SPAD readings at harvest were significantly correlated with total N, leaf dry weight (DW), and NO₃-N concentration. However, this correlation did not exist between SPAD readings and ascorbic acid concentrations in leaves. The above results suggest that it is possible to apply SPAD readings to estimate NO₃-N concentrations in spinach plants, and that they may be applied for field assessments in decision-making and operational nutrient-management programs for the plant. Furthermore, the SPAD method may also be useful for ascertaining the harvest time. The results suggest that treatment with 120 mg N/kg significantly improved both leaf yields and leaf quality (i.e., leaf nitrate-N concentration and ascorbic acid). Too little and too much N fertilizer was not good for yield or spinach quality.     

How Soil Pore Distribution Could Help in Soil Quality Studies as an Appropriate Indicator

Eurasian Soil Science - The present study is aimed at examining the impacts of land use and slope gradient on pore space distribution as well as some soil physicochemical properties. Three land...     

Precipitation Chemistry as an Indicator of Urban Air Quality in Mersin, North-Eastern Mediterranean Region

The chemical composition of precipitation in the city of Mersin on the Mediterranean coast of Turkey has been studied. Spatial and temporal variability of rainwater constituents have been determined from samples collected at two central and two suburban stations for the December 2003–May 2005 period. A total of 246 samples covering all precipitation events were analyzed to determine pH, conductivity, as well as major anion (Cl^?, ${\text{NO}}_3^ - $ , ${\text{SO}}_4^{2 - } $ ); major cation (H⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, ${\text{NH}}_4^ + $ ) and formaldehyde (HCHO) concentrations. The pH varied within a range of 4.8–8.5, with only 8 out of 246 samples being acidic (pH?<?5.6), and the remaining highly alkaline samples being neutralized by either ${\text{NH}}_4^ + $ in rainwater, or by CaCO₃ resulting from wet deposition of atmospheric dust. The volume weighted mean ΣAnion/ΣCation ratio was 0.49. The equivalent concentration of major ionic species followed the order: ${\text{Ca}}^{2 + } > {\text{HCO}}_3^ - > {\text{SO}}_4^{2 - } > {\text{Cl}}^ - > {\text{NH}}_4^ + > {\text{Na}}^ + > {\text{Mg}}^{2 + } > {\text{NO}}_3^ - > {\text{K}}^ + > {\text{H}}^ + $ . Formaldehyde concentrations varied in the range of 0.01–17.9 μM, and was found to be dependent on precipitation volume. Relatively higher ${\text{NH}}_4^ + $ , ${\text{SO}}_4^{2 - } $ , ${\text{NO}}_3^ - $ and HCHO concentrations, mainly of anthropogenic origin, measured near the city center suggest increased pollution from local anthropogenic sources, e.g., residential heating, industrial and/or traffic emissions. In general, the results of this study suggest local precipitation chemistry is more strongly influenced by natural (mineral dust and marine) sources compared to anthropogenic ones.     

Enhanced Microalgal Growth and Effluent Quality in Tertiary Treatment of Livestock Wastewater Using a Sequencing Batch Reactor

Water, Air, & Soil Pollution - The Pantanal is an extensive flooded plain, rich in biodiversity and considered a Biosphere Reserve and World Heritage Site. It has great complexity and can be...     

Changes in the Metagenome of Prokaryotic Community as an Indicator of Fertility of Arable Soddy-Podzolic Soils upon Fertilizer Application

The influence of different systems of fertilization and liming on the changes in the taxonomic structure of prokaryotic community in arable soddy-podzolic soil (Albic Retisol (Loamic, Aric, Cutanic, Differentic, Ochric)) was studied in a stationary field experiment of Vologda State Dairy Farming Academy with the use of high-performance sequencing method of gene 16S rRNA. The 25-year-old fallow plot, in which the intensity of microbiological processes was close to that in the virgin soddy-podzolic soils, was used as a control. At the first stage, dominant phyla were identified: Proteobacteria (45.3–56.2%), Actinobacteria (13.6–20.4%), Bacteroidetes (7.2–19.3%), Acidobacteria (7.1–11.5%), and Verrucomicrobia (4.3–10.3%). Several groups of microorganisms-indicators, whose portion changes in the arable soil under the influence of liming, fertilizer application, and soil treatment in comparison with the control, were determined. The applied approach made it possible to relate the taxonomic structure of the soil microbial cenosis with external factors for assessing changes in the structure of soil microbial complex under the impact of different uses of the arable soil.     

土壤微生物量作为土壤肥力指标的探讨

对不同利用方式19个黑土样品的微生物量和养分进行了分析,结果表明林地的微生物量明显高于玉米地和大豆地,但玉米地和大豆地之间未表现出显著差异,土壤微生物量和土壤养分含量大体上都呈现出林地>大豆地>玉米地的一致的趋势;同时土壤微生物量与土壤有机质、全氮、全磷、速效钾和碱解氮呈现出显著或极显著正相关关系,分析结果还表明土壤微生物量碳作为评价土壤肥力指标比土壤微生物量氮更为灵敏。因此,土壤微生物量可以作为评价不同利用方式的黑土肥力水平的一个生物指标。     

土壤微生物量碳氮作为土壤肥力指标的探讨

通过对不同肥力水平黑土、棕壤、黄棕壤、红壤土壤微生物量碳氮的比较,研究和探讨土壤微生物量碳氮与土壤肥力的关系。结果表明:有机肥或无机肥施入土壤均能增加土壤微生物量C、N的含量,且有机肥与无机肥配合有显著的正交互作用。土壤微生物量C、N从北到南的地带性变化规律不强。BC/BN及TC/TN从北到南逐渐减小,BC/TC及BN/TN从北到南逐渐增加。相关分析结果表明:土壤微生物量C、N与全C、全N均呈极显著相关,可以作为指示土壤肥力的重要指标。     

Activated Biochar as an Effective Sorbent for Organic and Inorganic Contaminants in Water

Adsorption is acknowledged as effective for the removal of pollutants from drinking water and wastewater. Biochar, as a widely available material, holds promises for pollutant adsorption. So far, biochar has been found to be effective for multiple purposes, including carbon sequestration, nutrient storage, and water-holding capacity. However, its limited porosity restricts its use in water treatment. Activation of biochars, when performed at a high temperature (i.e., 900 °C) and in the presence of certain chemicals (H₃PO₄, KOH) and/or gases (CO₂, steam), improves the development of porosity through the selective gasification of carbon atoms. Physicochemical activation process is appropriate for the production of highly porous materials. As well, the morphological and chemical structure of feedstock together with pyro-gasification operating conditions for the biochar production can greatly impact the porosity of the final materials. The effectiveness of activated biochar as adsorbent depends on porosity and on some functional groups connected to its structure, both of these are developed during activation. This study provides a comprehensive synthesis of the effect of several activated biochars when applied to the treatment of organic and inorganic contaminants in water. Results show that high aromaticity and porosity are essential for the sorption of organic contaminants, while the presence of oxygen-containing functional groups and optimum pH are crucial for the sorption of inorganic contaminants, especially metals. Finally, although activated biochar is a promising option for the treatment of contaminants in water, further research is required to evaluate its performance with real effluents containing contaminants of emerging concern.

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Ecogeochemical Investigation: Stream Water Quality as an Indicator of Pollution in the Border Areas of Finland, Norway and Russia

The Geological Surveys of Finland and Norway, and the Central Kola Expedition, Russia, carried out an environmental geochemical mapping project, including investigation of stream water quality. The project was carried out in 1992–1993 in the border areas of Finland, Norway and Russia, covering an area of 12 000 km², to determine the impacts of smelting industries at Nikel and Zapoljarnij. Stream water was one of eight different indicators providing an estimation of the degree and distribution of contamination in the study area. Contamination of surface water was assessed by analyses of 44 samples, 41 variables were measured on each sample. Indicators of human activities in surface waters are NO₃, K, electrical conductivity (EC), SO₄, Na, Cl and acidification indicated by alkalinity and pH. On the coast Na and Cl contents are also affected by marine salts. The results show considerably higher contents of K, Ca, Mg, SO₄, Na, heavy metals and EC in the samples close to Nikel and Zapoljarnij smelters than those sites more distant from the polluting sources. Especially chemical effects of high emissions of Ni, Cu and SO₂ on stream water quality from Nikel and Zapoljarnij smelters are clearly seen near the sources of emissions.     

Chemical and Ecotoxicological Assessment of Selected Biologically Activated Sorbents for Treating Wastewater Polluted with Petroleum Products with Special Emphasis on Polycyclic Aromatic Hydrocarbons

A chemical and ecotoxicological assessment of treatment of wastewater that had been polluted with petroleum products using only Activated Sludge (AS) and four biologically activated sorbents (BASs), consisting of activated sludge plus: coal-based activated carbon (-C1), coconut shell-based activated carbon (-C2), zeolite (-Z), and anthracite (-A) were conducted. The efficiency and robustness of the four wastewater treatment systems were evaluated by calculating the reduced total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) contents and the acute ecotoxicity of the effluents. The chemical analysis showed that the combined treatment systems were very effective for reducing the total petroleum hydrocarbon and readily bioavailable PAH contents. The most efficient systems were the BAS-C1 and -C2, which removed 60–88% and 99.5–99.6% of TPH and PAH, respectively. The activated sludge-only treatment was the least effective for purifying the wastewater. Chemical oxygen demand was reduced by >90% by all carbon-based BASs (BAS-C1, BAS-C2 and BAS-A). Shifts in the relative composition of the individual PAHs were identified in samples taken before and after treatment. Algal and bacterial bioassays showed that the toxicities of effluents following treatment by all four systems (except AS for algae) were reduced by more than 80% and 90%, respectively. However, crustacean tests indicated that the carbon-based BASs reduced the toxicity [V _tox(50)] only by 19–67%. Our results indicated that the combination of sorption and biodegradation processes have great potential in the treatment of petroleum products polluted wastewater and is less sensitive for inhibitors of the biological process than treatments in which activated sludge alone is used. The assessment of chemical and ecotoxicological endpoints provided valuable information, but contrasting results for one of the assays indicates that further analysis on the capacity of the different treatment systems is warranted.