Investigation of appropriate initial composition and aeration method for co-composting of yard waste and market wastes

The purpose of this research was to shorten the composting period by speeding up the composting process and to obtain good quality compost that can be used in agriculture. In order to accomplish the acceleration of the process, different mixtures of feedstock were loaded to the composting containers to observe the effect of initial composition on the quality of the compost and the rate of composting. The first feedstock prepared was composed of grass, leaves and market waste whereas the second feedstock composed only of leaves and market wastes. Composting process was accomplished by applying different composting methods such as composting without manual stirring, with manual stirring, with aeration by air, with aeration by oxygen, with manual stirring and aeration by air and finally by with manual stirring and aeration by oxygen to achieve the purpose of the research. Aeration was found as a primary requirement for the acceleration of composting because it was observed that when the aeration was not applied the conversion of nutrients was very low. The high conversion efficiency of the nutrients in the feedstock with market and yard wastes-without grass-resulted in higher quality end product. The organic content of the composted yard and market wastes were monitored and the best operational parameters and methods were identified. Parameters such as temperature, moisture, pH and end-product metal contents were also monitored in the study. and the experiments were run in duplicates. Corrected C/N, (C/N)t/(C/N)initial, were used in the calculations which provided objectivity in comparison of the compost quality with respect to nutritional components. The C/N change was found to be higher in the container that was manually stirred and aerated with oxygen but with regard to the economic feasibility of the system aeration with air was preferred. Compost quality that was achieved in the study was compared to the standards of different countries with respect to the amount of metal contents in the end-product. The applicability of the end-product in agriculture depends on the level of contaminants in the compost, especially metals that have to be present only in trace amounts.     

Methane oxidation in two Swedish landfill covers measured with carbon-13 to carbon-12 isotope ratios

The release of methane (CH4) from landfills to the atmosphere and the oxidation of CH4 in the cover soils were quantified with static chambers and a 13C-isotope technique on two landfills in Sweden. One of the landfills had been closed and covered 17 years before this investigation while the other was recently covered. On both landfills, the tops of the landfills were compared with the sloping parts in the summer and winter. Emitted CH4, captured in chambers, was significantly enriched in 13C during summer compared with winter (P < 0.0001), and was enriched relative to anaerobic-zone methane. The difference between emitted and anaerobic zone delta 13C-CH4 was used to estimate soil methane oxidation. In summer, these differences ranged from 9 to 26@1000, and CH4 oxidation was estimated to be between 41 and 50% of the produced CH4 in the new landfill, and between 60 and 94% in the old landfill. In winter, when soil temperature was below 0 degree C, no difference in delta 13C was observed between emitted and anaerobic-zone CH4, suggesting that there was no soil oxidation. The temperature effect shown in this experiment suggests that there may be both seasonal and latitudinal differences in the importance of landfill CH4 oxidation. Finally the isotopic fractionation factor (alpha) varied from 1.023 to 1.038 and was temperature dependent, increasing at colder temperatures. Methanotrophic bacteria appeared to have high growth efficiencies and the majority of the methane consumed in incubations did not result in immediate CO2 production.     

Sorption of polycyclic aromatic compounds to humic and fulvic acid HPLC column materials

Two different humic acids (HA) and a fulvic acid (FA) were chemically immobilized to a high performance liquid chromatography (HPLC) silica column material. The immobilization was performed by binding amino groups in HA/FA to the free aldehyde group in glutardialdehyde attached to the silica gel. The HPLC column materials were compared with a blank column material made by applying the same procedure but without immobilizing HA or FA. Also, a column was made by binding carbonyl groups in HA to amino groups attached to the silica gel. The humic substances were selected to secure appropriate variation of their structural features. The retention factors of 45 polycyclic aromatic compounds (PAC) to the four columns were determined by HPLC. The advantage of the technique is a large number of compounds can easily be studied. The binding procedure does not appear to cause a drastic selection between the HA molecules. The k' values obtained for the two Aldrich HA columns agree in general reasonably. The retention or sorption of the compounds increased with the size of the PAC and the number of lipophilic substituents, but decreased when polar substituents were present. The PAC retention was much stronger to the two HA columns than to the FA and blank column, both for hydrophobic polycyclic aromatic hydrocarbons (PAH) and the polar PAC. Other factors impacting the PAC binding may be specific interactions with HA and the ionic strength of the aqueous phase. The technique has been applied to do direct determinations of Koc.     

Bioremediation of residual fertilizer nitrate: II. Soil redox potential and soluble iron as indicators of soil health during treatment

The prospect of using wastewater containing high loads of soluble organic matter (OM) for removing residual agricultural chemicals (fertilizer, pesticide, or herbicide) in farm soil, although promising, could have adverse effects on soil agricultural quality as a result of development of redoximorphic features in the soil profile. In this study, the effect of organic carbon supplement for bioremediation of residual fertilizer nitrate on soil properties, redox potential (Eh), pH, and metal ion mobilization was studied using sandy soils packed in columns. The study was included in a general project, described elsewhere (Ugwuegbu et al., 2000), undertaken to evaluate use of controlled water table management (WTM) systems to supply organic carbon for creating a reduced environment conducive to denitrification of residual fertilizer nitrate leaching from the farm to subsurface water. The columns were subjected to subirrigation with water containing soluble organic carbon in the form of glucose. The work was carried out in two experimental setups and the long-term effect of a range of glucose concentrations on the Eh, pH, and soluble levels of Fe and Mn was investigated. From the results obtained, it could be concluded that excessive organic carbon supplement to soil can have adverse effects on soil quality and that Eh and soluble Fe are the two most practical parameters for monitoring soil health during treatment of farm chemicals.     

The consequences of tourism for sustainable water use on a tropical island: Zanzibar, Tanzania

Many developing countries in the tropics have focused on tourism to generate additional income sources and to diversity the economy. Coastlines in particular have been on the forefront of tourist infrastructure development. Here, the presence of a large number of tourists has often had negative consequences for the sustainable use of the available resources, which in turn has had an effect on the integrity of the ecosystems. In this paper, the situation is described for the use of freshwater resources on the east coast of Zanzibar, Tanzania. This region is water poor, relying on freshwater derived from seasonal rains and stored in less efficient aquifers, which consist of freshwater lenses floating on the underlying seawater. Tourism in the area has grown rapidly in recent years and is expected to further increase in the future. This development is expected to put additional pressure on the freshwater resources of the east coast, which show already signs of over-use. The consequences of overexploitation can include the lowering of the groundwater table, land subsidence, deteriorating groundwater quality, and saltwater intrusion. These, in turn, determine the living conditions in coastal areas and the effects will be felt both by the local populations and the tourist industry. An investigation is made into the causes and consequences of water abstraction by the tourist industry. The results show that present levels of withdrawal are not sustainable, and parts of the local populations are already experiencing water deficits on a daily basis. In the future, if the expected increase in tourist numbers occurs, the pressure on the aquifers will correspondingly increase. The results could be that the tourism in the area becomes unsustainable, which could have an adverse effect on the national economy and also on the local population and environment. Therefore, a precautionary water-management approach is suggested.     

Contamination of Austrian soil with caesium-137

Austria ranks among the countries that have been most strongly affected by the Chernobyl fallout. The mean contamination with 137Cs is 21.0 kBq/m2, of which 18.7 kBq/m2 is due to the Chernobyl accident, whereas global fallout contributes 2.3 kBq/m2. Maximum values of total 137Cs contamination are nearly 200 kBq/m2. Total deposition of Chernobyl 137Cs on Austrian territory is 1.6 PBq or a fraction of around 2% of the 137Cs released from the reactor. 2115 measurements were used to draw the Austrian "caesium map". The geographical pattern of fallout distribution shows regional differences of contamination as high as 1:100.     

Monitoring, modelling and environmental exposure assessment of industrial chemicals in the aquatic environment

Monitoring and laboratory data play integral roles alongside fate and exposure models in comprehensive risk assessments. The principle in the European Union Technical Guidance Documents for risk assessment is that measured data may take precedence over model results but only after they are judged to be of adequate reliability and to be representative of the particular environmental compartments to which they are applied. In practice, laboratory and field data are used to provide parameters for the models, while monitoring data are used to validate the models' predictions. Thus, comprehensive risk assessments require the integration of laboratory and monitoring data with the model predictions. However, this interplay is often overlooked. Discrepancies between the results of models and monitoring should be investigated in terms of the representativeness of both. Certainly, in the context of the EU risk assessment of existing chemicals, the specific requirements for monitoring data have not been adequately addressed. The resources required for environmental monitoring, both in terms of manpower and equipment, can be very significant. The design of monitoring programmes to optimise the use of resources and the use of models as a cost-effective alternative are increasing in importance. Generic considerations and criteria for the design of new monitoring programmes to generate representative quality data for the aquatic compartment are outlined and the criteria for the use of existing data are discussed. In particular, there is a need to improve the accessibility to data sets, to standardise the data sets, to promote communication and harmonisation of programmes and to incorporate the flexibility to change monitoring protocols to amend the chemicals under investigation in line with changing needs and priorities.     

WATER QUALITY SIMULATION AND PUBLIC LAW 92–500 Case Study: Southwestern Illinois1

ABSTRACT: Section 208 of the Federal Water Pollution Control Act Amendments of 1972 has provided the Southwestern Illinois Metropolitan and Regional Planning Commission (SIMAPC) with a unique opportunity for comprehensive planning of the region's water quality. SIMAPC initiated the 208 study by researching available technology for the analysis of point and nonpoint sources of pollution and establishing criteria by which to judge the various technniques. This led to SIMAPC'S choice of continuous simulation of stream and reservoir water quality as the most appropriate analytical tool for their needs. A continuous simulation model was calibrated and verified on three basins in the SIMPAC region. It was then used to produce load source analysis, pollution event frequency analysis, and pollution event duration analysis for ten pollutants under existing stream conditions and then under alternative future conditions. These results enabled the weighting of pollutant sources, analysis of the effectiveness of control measures, and quantitative analysis of the marginal benefit of each alternative.     

CADMIUM ACCUMULATION AND TOXICITY IN SUBMERGED PLANT HYDRILLA VERTICILLATA (l.f.) ROYLE

Cadmium accumulation and its toxicity in relation tochlorophyll, protein, cysteine contents and in vivo nitrate reductaseactivity were studied under controlled conditions in Hydrillaverticillata, a submerged commonly occurring macrophyte. Plants weresubjected to six different concentrations of Cd ranging from 1.0 to 25.0 µM for 24, 48, 72 and 168 h. Tissue Cd concentration was maximum (13.71 µmoles/g dw) at 25 µM background concentration. At this concentration, a decrease of approximately 79 and 72% was found in chlorophyll and protein content. In vivo nitrate reductase activity was stimulated at 1.0 µM; however, the activity gradually declined beyond this concentration. Exposure to various cadmium concentrations resulted in an increase in cysteine content of the plant.     

Mass Spectrometric Detection and Identification of Polar Pesticides and their Degradation Products - A Comparison of Different Ionization Methods

Due to increasing use of polar pesticides, they are found together with their degradation products in ground- and surface waters serving for drinking water treatment. The triazine derivatives acetamido-atrazine, ametryne, atrazine, cyanazine, deethylatrazine, deethyldeisopropyl-hydroxyatrazine, deethyl-hydroxyatrazine, deisopropyl-atrazin, deisopropyl-hydroxyatrazine, desmetryn, hydroxyatrazine, prometryne, propazine, simazine, terbumeton, terbutryne and terbutylazine, and the pesticides 2,4-D, dichlorprop, isoproturon, diuron, metolachlor, glyphosate, metsulfuronmethyl and dalapon, all of them belonging to this type of pesticides, have been studied. For determination of triazine derivatives UV detection by means of diode array detector (DAD) as well as mass spectrometric (MS) detection coupled by thermospray interface (TSP) have been used successfully after liquid chromatoraphic (LC) separation. Interfaces like thermospray (TSP), electrospray (ESP) and atmospheric pressure chemical ionisation (APCI) were examined with regard to their suitability for substance-specific detection of polar pesticides by flow injection analysis (FIA) with MS- and tandem mass spectroscopic detection (MS/MS) without preceding LC separation. Optimised detection conditions for these pesticides using FIA are presented, and solutions for occurring problems are offered.