Zur Bestimmung des gesamten anorganischen Kohlenstoffes in natürlichen Gewässern durch Titration mit Salzsäure

The knowledge of total inorganic carbon concentration (c) is important for characterizing natural waters. It is usually measured by the titration alkalinity (“m-value”) and pH which depend on temperature and ionic strength. This paper demonstrates that Ca (and Mg) can influence the calculation of from titration alkalinity, too. Errors result from neglecting this influence. In such cases the share of ion pair CaCO amounts to more than 50 % of . General relationships among the influencing factors are given by tables calculated with the help of a BASIC computer programme for calculation from titration alkalinity, pH and Ca concentration.     

Untersuchungen zur Phosphataufnahme durch Unterwasserpflanzen

The uptake of phosphorus by Potamogeton pectinatus, P. lucens, Ranunculus fluitans, Elodea canadensis, Myriophyllum spicatum and Ceratophyllum demersum is investigated in batch tests at 0.02, 0.04, 0.4 and 4.0 mg/l PO in the medium for 4, 28 and 52 h. Uptake is strictly dependent on concentration, a saturation function being discernible already after 52 h. At rising concentration the mechanism of uptake is determined by a decreasing rate of incorporation. The rates of uptake are dependent also on the actual and maximum cell nutrient contents. Species with a low phosphorus content of <5 mg PO/g dry weight as Elodea canadensis, Potamogeton pectinatus and Myriophyllum spicatum show their maximum phosphorus incorporation at low substrate concentrations. At phosphorus contents >5 mg PO/g dry weight the phosphorus incorporation is increased only at substrate concentrations of 0.04… 0.4 mg/l PO.     

Species Composition and Seasonal Variations of the Gastropoda in Upper Sakarya River System (Turkey) in Relation to Water Quality

Species composition, abundance, and seasonal distribution of the Gastropoda fauna and the physical and chemical variables of Upper Sakarya River System have been investigated between October 1998 and August 1999. Gastropod fauna in the Upper Sakarya River System was represented by 9 species of Prosobranchia and 7 species of Pulmonata. Diversity, dominance, and abundance of the Gastropoda species were recorded seasonally. The abundance of some of the 16 species was correlated positively with temperature, dissolved oxygen and negatively or positively with pH and nitrate. It was observed that Gyraulus albus (Müller, 1774), Physa acuta Draparnaud, 1805, Valvata pulchella Studer, 1820, and Oxyloma elegans (Risso, 1826) can tolerate a high level of NO‐N while V. piscinalis (Müller, 1774) spread out in unpolluted water. Although the species and their numbers change at the stations, the maximum numbers were found during autumn, while minimums were identified during the winter sampling. Gyraulus albus was the most widespread species in our research area. Only 5 species (Gyraulus albus, Physa acuta, Valvata cristata (Muller, 1774), Valvata pulchella, Melanopsis praemorsa costata (Olivier, 1804)) were determined each season. However, no Gastropoda were found at the station 3 that has high BOD, NO‐N, NO‐N, and NH₃ levels.     

A Contribution to the Mechanism of Elimination of Dimethylformamide and Dimethylamine by a Heterogenous Culture of Microorganisms

In a batch experiment with activated sludge from a large-scale plant the hydrolytical and biochemical degradation of dimethylformamide (DMF) and its reaction product dimethylamine (DMA) and the conversion connected with this under aerobic and anaerobic conditions is investigated. Parallel to the hydrolysis of DMF the biochemical degradation of DMA occurs. The extensive conversion of these substrates is followed by the nitrification of the ammoniumions formed, and under subsequent anaerobic conditions with methanol as the carbon source also denitrification can be achieved. If the oxygen supply of the activated sludge is insufficient, however, also DMA can be used as a carbon source for denitrification, ammonium-ions being released from DMA in addition. In the batch experiment the elimination rates referred to nitrogen were 7 … 14 mg/g · h for DMF, 0.8 … 1.7 mg/g · h for DMA, 0.3 … 0.6 mg/g · h for NH and 0.4 to 1.3 mg/g · h for nitrate in the presence of methanol. DMF and DMA are obviously not suitable as the only carbon source for denitrification.     

Zur ökonomischen Bedeutung der biologischen Selbstreinigung

In twelve flowing water (Q 1.04… 30.4 m³/s, 0.5… 1.2 m/s) the self-purification efficiency in 110 river sections (L 1.3… 26.4 km) is determined as the load difference in kg · d^?1 COD-Mn as well as in g · m^?3 referred to the daily passage. In the economical comparison, the self-purification efficiency is valued as substitution for wastewater treatment plants of the same capacity. At a mean specific capacity of 8.6 g · m^?3, the self-purification efficiency of the investigated waters is equivalent to economical values of 124 · 10³… 534 · 10³ M km^?1 investment costs, 11 · 10³… 80 · 10³ M · a^?1km^?1 operating costs and 5… 81 MWh · a^?1 km^?1 expenditure of energy. The specific capacity in g · m^?3 COD-Mn shows an exponential regression to the degree of saprobity (L = 0.015 · exp (1.7358 · S)). From this empirical model the limits of the self-purification capacity of aerobic waters by oxygen input can be detected: in respective examples more than 50% of the required oxygen input are due to weirs.     

Nitrat im Trinkwasser — hygienische und aufbereitungstechnische Probleme

The increasing nitrate concentrations in the ground water and drinking water which are caused by intensified fertilizing lead to the risk of methaemoglobinaemia of babies and increase the cancerogenic, teratogenic and mutagenic risk for the total population. In the drinking water conditioning the nitrate concentration can be reduced by different techniques. By ion exchange first the SO₄-ions and then the nitrate-ions are removed. Very favourable is the exchange for HCO and the regeneration by means of carbon dioxide and CaCO₃, for which a mass balance of substances is given. With 0.55 DM/m³ also the reverse osmosis in a mixture with raw water is practicable and also electrodialysis can be applied, whereas the biological techniques of the heterotrophic or autotrophic denitrification still include unsolved technological problems due to the necessity of an organic substrate or of H₂. The special features of each of these techniques and the hygienic and also the corrosion-chemical consequences are indicated.     

Impact of Urban Surroundings on Some Limnological Characteristics of a Tropical Aquatic Ecosystem

The water quality of an urban pond in the thickly populated area of Varanasi city (5 km apart) was studied and compared with a rural pond in the Banaras Hindu University campus for transparency, conductivity and nutrient richness (Cl^?, SO, PO? P, NO? N, organic carbon, Ca²⁺, Mg²⁺, K⁺, Na⁺) at three depths (surface, 1.5 m, 3 m) at monthly intervals between February 1982 and February 1983. This was done to assess the effects of urban surroundings of a very ancient city sector on pond water quality in reference to that of a rural pond. The rural pond had a lush growth of 12 macrophytic species, whereas the urban one had only such a growth with many phytoplanktonic species. Transparency was maximum in the winter season and the rural pond water was more transparent, while the electrolytical conductance was maximum in the rainy season, being higher in the urban pond. Electrolytical conductivity was negatively correlated to transparency: urban: EC = 1081.612–6.575 T, r² = 0.897, F_1,11 = 96, P <0.005; rural: EC = 728.981–4.328 T, r₂ = 0.892, F_1,11 = 91, P <0.005. Chloride and sulphate concentrations were highest in summer months, but the former was much higher in the urban pond while the latter in the rural pond. NO₃–N was highest in the rainy season in the rural pond and in early winter in the urban one and showed a definite trend with change in depth. PO₄–P also varied with depth and time and it was higher in late summer and the early rainy season in the rural pond and in early winter in the urban pond. But both these nutrients were much higher in the urban pond. The maximum organic carbon concentration was found in the rainy season in the rural pond and in summer months in the urban pond. The variation of organic carbon with depth was distinct. Both summer and winter seasons showed almost similar values of calcium concentration in the rural pond, but in the urban pond it was maximum in summer. Organic carbon and calcium were higher in the urban pond. The magnesium concentration was highest in rainy months in both the ponds, but the periodicity of the minimum differed. The distribution of calcium with depth was not well defined. The highest concentration of potassium was found in the winter season in both the ponds. The sodium concentration in the rural pond was observed maximum in summer and minimum in the rainy season, but in the urban pond the trend was different. The variation of potassium and sodium with depth was not well defined. Magnesium and sodium were also higher in the urban pond but potassium was almost at the same concentration in both the ponds. The effect of urbanisation may be one of the factors which might be responsible to the shift of the species composition towards phytoplanktonic flora.     

Simulation des Nitratabbaus im Grundwasser

Ten reaction vessels containing 1 m³ were used as the experimental arrangement. They were filled with coarse sand or fine gravel and installed 60 cm below the floor. The pore volume (water saturation) was 227… 260 l. Anaerobic conditions were established by the addition of 6 g glucose at storage. The reactors were given tap water with 50 and 200 mg/l NO from KNO₃ in such a way that a volumetric rate of flow of 0.2, 0.4 and 0.8 l/d was created. The volumetric rates of flow corresponded to the natural recharge of groundwater, the recharge of groundwater under the conditions of irrigation and the conditions of an intensive wastewater ground treatment. In the effluent from the reaction vessels the nitrate concentration was determined every month. It was stationary from the 7th to the 55th month after the beginning of the experiment. The experiments are evaluated by means of a model which takes into account the diffusion, convection and kinetics of the nitrate degradation according to Michaelis-Menten. A simple method for solving homogeneous non-linear differential equations of the second order is proposed. The experimental and model results show a good agreement and prove the very slow nitrate degradation in the groundwater with k_M = 210 mg/l, v_max = 1.5 mg/l · d or k₁ = 0.005 d^?1.     

H2S Emissions from a Submerged Pilot‐Scale Fixed Bed Biofilm Reactor

A study was performed in two submerged, pilot‐scale biofilm bioreactors operated under different conditions to determine the relationship between the operating parameters and H₂S emission. H₂S was always detected in the exhaust air at concentrations varying from 1 to 353 ppm_v. The specific aeration rate was the most influencing parameter, with As < 30 kg COD (dissolved oxygen concentrations <4 mg L^?1) increasing noticeably the H₂S production. The periodical removal of the accumulated sludge reduced H₂S emissions by ～14%.     

Chemical dynamics of N-containing ionic species in a boreal forest snowcover during the spring melt period

A study of the changes in the ionic loads of NO, NH, SO and H⁺ in a boreal forest snowpack at Lake Laflamme, Québec was carried out using hydrological and chemical data from field lysimeters. The results showed that depletion of the N-containing species occurs periodically in the snowpack during meltwater discharge. Rain-on-snow events led to in-pack losses of NO and NH at a rate of 130 μeq m^?2 day^?1 and 101·3 μeq m^?2day^?1 respectively. On dry days, however, dry deposition and deposition of organic debris from the canopy resulted in increases of 183·3 μeq m^?2day^?1 for NO and 4·5 μeq m^?2day^?1 for NH in the pack. In contrast, SO₄^2? showed continual in-pack increases due to deposition of 5·0 μeq m^?2day^?1 for wet days and 92·6 μeq m^?2day^?1 for dry days. The depletion of NO and NH is due to microbiological uptake of these nutrients during periods when the free water content of the pack is high. Controlled melts in a laboratory snowmelt simulator containing snow and organic matter from the forest canopy at Lake Laflamme showed losses of NO and NH similar to those observed in the field. As the microbiological uptake proceeds at a rate comparable to that of ionic load increases in the pack by dry deposition, models of the chemical dynamics of snowmelt should take the former into account in any system where organic content of the snowpack is appreciable.     

Regulating Environmental Factors of Nutrients Release from Wheat Straw Biochar for Sustainable Agriculture

One mechanism by which biochar application enhances soil nutrient availability is through direct nutrients release from biochar. However, factors controlling the release processes are poorly understood. In this study, the effects of pH, biochar to water ratio, temperature, ionic strength, and equilibration time on the release of PO, NO, NH, K⁺, Na⁺, Ca²⁺, and Mg²⁺ from biochar were evaluated in simulated experiments. The release of PO, K⁺, Ca²⁺, and Mg²⁺ was significantly affected by extraction pH, suggesting that their release from biochar was pH dependent or an H⁺‐consuming process. Correlation analysis indicated that PO and Ca²⁺, PO and Mg²⁺, and Ca²⁺ and Mg²⁺ were co‐solubilized with increasing soil acidity. To a lesser extent, the recovery of the nutrients was also affected by the ratio of biochar to water: more nutrients were soluble with more water supply. In contrast, the release of Na was not affected by pH while the concentration increased with decreasing biochar to water ratio. Meanwhile, other factors (temperature, ionic strength, and equilibration time) had less effect on nutrient release from biochar. Under the influence of pH, the patterns of NO and PO release from biochar were different: extractable NO concentration was not affected by the pH but more PO was released in strongly acidic conditions. Our data suggested that P was mainly retained in inorganic forms while N was in organic forms in biochar. We conclude that environmental factors have marked influences on nutrients release from biochar.     

Removal of Bromate from Water Using De‐Acidite FF‐IP Resin and Determination by Ultra‐Performance Liquid Chromatography‐Tandem Mass Spectrometry

Contamination of water due to bromate is a severe health hazard. The aim of the present study was to remove bromate from water using a crosslinked polystyrene based strongly basic anion exchange resin De‐Acidite FF‐IP. Batch experiments were performed to study the influence of various experimental parameters such as effect of pH, contact time, temperature, and effect of competing anions on bromate removal by De‐Acidite FF‐IP resin. At optimum parameters, the removal rate of bromate was very fast and 90% removal took place in 5 min and equilibrium was established within 10 min. The presence of competitive anions reduced the bromate adsorption in the order of Cl^? > F^? > CO > SO > NO > PO. The practical utility of this resin has been demonstrated by removing bromate in some of the commercial bottled water from Saudi Arabia. The level of bromate was determined using a very sensitive, precise and rapid method based on ultra‐performance liquid chromatography‐tendem mass spectrometry (UPLC‐MS/MS).     

Temporal trends of bulk precipitation and stream water chemistry (1977–1997) in a small forested area,Krusné hory,northern Bohemia,Czech Republic

The Krusné hory (Erzgebirge or Ore Mountains) has been heavily affected by high atmospheric pollutant deposition caused by fossil fuel combustion in an adjacent Tertiary coal basin. Long‐term routine sampling of bulk precipitation (1977–1996) and stream water (1977–1998) in a forested area on the south‐eastern slope of the mountains were used to evaluate trends and patterns in solute concentration and flux with respect to controlling processes. From 1977 to 1996, the annual volume‐weighted Ca²⁺ and SOconcentrations decreased in bulk precipitation. However, after 1989, when a pronounced and continuous decrease occurred in coal production, annual volume‐weighted concentrations decreased for most solutes, except H⁺. The concentration decreases were marked, with 1996 levels at or below 50% of those in 1989. The lack of a trend in H⁺ is attributed to similar decreases in both acid anions and neutralizing base cations. Stream water concentrations of most solutes, i.e. H⁺, Ca²⁺, Mg²⁺, SONOwere highest at the onset of sampling in 1977, decreased markedly from 1977 to 1983 and decreased more gradually from 1983 to 1998. The spruce forest die‐back and removal reduced dry deposition of these solutes by reducing the filtering action, which was provided by the forest canopy. A notable decrease in stream water Ca²⁺ concentrations occurred after 1995 and may be due to the depletion of Ca²⁺, which was provided by catchment liming in 1986, 1988 and 1989. Solute flux trends in bulk atmospheric deposition and stream water generally were not significant and the lack of trend is attributed to the large interannual variability in precipitation quantity and runoff, respectively. All solutes except Na⁺ varied seasonally. The average seasonal concentrations varied between the solutes, but for most solutes were highest in winter and spring and lowest in summer, correlating with the seasonal trend in runoff. For Ca²⁺, Mg²⁺ and SOthe concentration minimum occurs in September and the maximum occurs in February or March, correlating with the seasonal baseflow. These solutes are primarily controlled by the contribution of soil water and groundwater to stream flow. During snowmelt, the meltwater generally causes concentrations to decrease as soil water and groundwater are diluted. For NO₃ , average minimum concentrations occur in August at the end of the growing season concurrent with the lowest stream flow, and the maximum occurs in February and March with high stream flow during snowmelt. Seasonal stream water NOconcentration variations are large compared with the long‐term decrease. Copyright © 1999 John Wiley & Sons, Ltd.     

Monitoring of Impact of Ferti‐irrigation by Post‐methanated Distillery Effluent on Groundwater Quality

The impact assessment of molasses‐based distillery‐effluent irrigation on groundwater quality around village Gajraula in the district of Jyotiba Phule Nagar, Uttar Pradesh, India was studied by sampling groundwater on monthly intervals consecutively for summer, winter and monsoon seasons during 2006–2007 and water quality parameters, viz. pH, electrical conductivity (EC), chloride (Cl^?), sulphate (SO), nitrate (NO), chemical oxygen demand (COD), total solids (TS), total dissolved solids (TDS), sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), magnesium (Mg²⁺), zinc (Zn²⁺), iron (Fe³⁺), and total coliforms (TC) were monitored. Results depicted that the values of all parameters decreased with increasing depth of water table. Sulphate, nitrate and potassium contents were maximal in agricultural site during monsoon while EC, Cl^?, TS, TDS, Na⁺, Ca²⁺, Mg²⁺, Zn, and Fe were maximal in industrial sites during summer. Groundwater samples of residential site harboured maximum coliforms especially during monsoon, highlighting threat to groundwater. Significant positive correlation matrix between coliforms with nitrate, sulphate and potassium ions explained their survival on these nutrients. To overcome this, important measures emphasizing improvement in effluent treatment technology matching site‐specific characteristics are recommended for eco‐friendly ferti‐irrigation.     

Atmospheric and Surface Water Pollution Interpretation in the Gdańsk Beltway Impact Range by the Use of Multivariate Analysis

The present study deals with the application of the hierarchical cluster analysis and non‐parametric tests in order to interpret the Gdańsk Beltway impact range. The data set represents concentration values for major inorganic ions (Na⁺, NH, K⁺, Mg²⁺, Ca²⁺, F⁻, Cl⁻, NO, and SO) as well as electrolytic conductivity and pH measured in various water samples [precipitation, throughfall water, road runoff, and surface water (drainage ditches, surface water reservoirs, and spring water)] collected in the vicinity of the beltway. Several similarity groups were discovered both in the objects and in the variables modes according to the water sample. In the majority of cases clear anthropogenic (fertilizers usage and transport, road salting in winter) and semi‐natural (sea salt aerosols, erosion of construction materials) impacts were discovered. Spatial variation was discovered for road runoff samples and samples collected from surface water reservoirs and springs. Surprisingly no clear seasonal variability was discovered for precipitation chemistry, while some evidences for existing of summer and winter specific chemical profile was discovered for road runoff samples. In general, limited range of the Gdańsk Beltway impact was proven.     

Solutes in overland flow following fire in eucalyptus and pine forests,northern Portugal

Small bounded plots were used to investigate dissolved nutrient losses in overland flow in eucalyptus and pine forests in northern Portugal following understorey fires. Losses of NON, POCa²⁺, Mg²⁺ and K⁺ were measured over 19 months during the first 2–3 years after fire. Solute losses in overland flow increased after fire in eucalyptus and pine terrain due to the mineralization of litter and vegetation and increased overland flow. The data suggest that (i) elevated losses persist for at least 2 and 3 years at the pine and eucalyptus sites respectively and (ii) soluble losses of POK⁺ in a post‐fire cycle may exceed those adsorbed to eroded material. Losses of POalthough relatively small, are potentially the most detrimental to soil fertility and forest productivity because of the limited opportunity for P replenishment and correspondingly high P losses adsorbed to eroded sediment. Copyright © 2000 John Wiley & Sons, Ltd.     

Photocatalytic Degradation of 17α‐Ethinylestradiol and Inactivation of Escherichia coli Using Ag‐Modified TiO2 Nanotube Arrays

Ag‐modified TiO₂ nanotube arrays (Ag/TiO₂ NAs) were prepared and employed as a photocatalyst for degradation of 17α‐ethinylestradiol (EE2) and inactivation of Escherichia coli. The as‐synthesized Ag/TiO₂ NAs were characterized by field‐emission scanning electron microscope (FESEM), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). It was found that metallic Ag nanoparticles were firmly deposited on the TiO₂ NAs with the pore diameter of 100 nm and the length of 550 nm. Photocatalytic degradation of EE2 and inactivation of E. coli were enhanced effectively in an analogical trend using Ag/TiO₂ NAs. In particular, Ag/TiO₂ NAs exhibited the antimicrobial activity even in the absence of light. The Ag acted as a disinfection agent as well as the dopant of the modified TiO₂ NAs photocatalysis by forming a Schottky barrier on the surface of TiO₂ NAs. Inorganic ions suppressed the rates of photocatalytic degradation of EE2, with HCO having a more pronounced effect than NO or SO. Humic acid (HA) was found to increase the rate of EE2 degradation.     

Nitrifying and Denitrifying Bacteria in Epiphytic Communities of Submerged Macrophytes in a Treated Sewage Channel

A quantification of nitrifying and denitrifying bacteria present in different compartments (water, sediments, submerged macrophytes) of a treated sewage channel was made to estimate their influence on the nitrogen balance and to assess the significance of macrophytes for nitrification and nitrogen conversions in general. Considerable numbers of autotrophic and heterotrophic nitrifying and denitrifiying bacteria were found to be present in the epiphytic communities of different species of submerged macrophytes of a treated sewage channel. Comparing the influence of the different compartments on total stream nitrification and denitrification it could be concluded that dense beds of submerged macrophytes particularly positively influence nitrification. Epiphytic nitrifiers were estimated to be as important for the total nitrification as nitrifiers in the sediment. Denitrification was mainly taking place in the sediment. The influence of the suspended nitrifiers and denitrifiers on the nitrogen balance was assumed to be negligible.     

Catalytic Reduction of Hexaminecobalt(III) by Pitch‐based Spherical Activated Carbon (PBSAC)

The wet ammonia (NH₃) desulfurization process can be retrofitted to remove nitric oxide (NO) and sulfur dioxide (SO₂) simultaneously by adding soluble cobalt(II) salt into the aqueous ammonia solution. Activated carbon is used as a catalyst to regenerate hexaminecobalt(II), Co(NH₃), so that NO removal efficiency can be maintained at a high level for a long time. In this study, the catalytic performance of pitch‐based spherical activated carbon (PBSAC) in the simultaneous removal of NO and SO₂ with this wet ammonia scrubbing process has been studied systematically. Experiments have been performed in a batch stirred cell to test the catalytic characteristics of PBSAC in the catalytic reduction of hexaminecobalt(III), Co(NH₃). The experimental results show that PBSAC is a much better catalyst in the catalytic reduction of Co(NH₃) than palm shell activated carbon (PSAC). The Co(NH₃) reduction reaction rate increases with PBSAC when the PBSAC dose is below 7.5 g/L. The Co(NH₃) reduction rate increases with its initial concentration. Best Co(NH₃) conversion is gained at a pH range of 2.0–6.0. A high temperature is favorable to such reaction. The intrinsic activation energy of 51.00 kJ/mol for the Co(NH₃) reduction catalyzed by PBSAC has been obtained. The experiments manifest that the simultaneous elimination of NO and SO₂ by the hexaminecobalt solution coupled with catalytic regeneration of hexaminecobalt(II) can maintain a NO removal efficiency of 90% for a long time.     

Accuracy of kinematic wave and diffusion wave approximations for time-independent flows

Errors in the kinematic wave and diffusion wave approximations for time-independent (or steady-state) cases of channel flow were derived for three types of boundary conditions: zero flow at the upstream end, and critical flow depth and zero depth gradient at the downstream end. The diffusion wave approximation was found to be in excellent agreement with the dynamic wave approximation, with errors in the range 1–2% for values of KF (? 7.5), where K is the kinematic wave number and F₀ is the Froude number. Even for small values of KF (e.g. KF²₀ = 0.75), the errors were typically less than 15%. The accuracy of the diffusion wave approximation was greatly influenced by the downstream boundary condition. The error of the kinematic wave approximation was found to be less than 13% in the region 0.1 ? x ? 0.95 for KF = 7.5 and was greater than 30% for smaller values of KF (? 0.75). This error increased with strong downstream boundary control.