Anaerobic co-digestion of table olive debittering & washing effluent, cattle manure and pig manure in batch and high volume laboratory anaerobic digesters: effect of temperature.

The prospective of table olive debittering & washing Effluent (DWE) as feed stock wastewater for anaerobic digestion (AD) systems was investigated in batch and continuous systems together with cattle and pig manures. While DWE considered unsuitable for biological treatment methods due to its unbalanced nature, the co-digestion of the wastewaters resulted in a 50% increase in the methane production/gram volatile solids(added) (CH(4)/gVS(added)), accompanied by 30% phenol reduction and 80% total organic carbon removal (TOC). pH increase during the co-digestion period was not identified as an inhibitory factor and all reactors were able to withstand this operational condition change. Moreover, no volatile fatty acid (VFA) accumulation was observed, indicating that the reactors were not operating under stress-overloading state. Under thermophilic conditions a 7% increase on the TOC removal efficiency was achieved when compared to the mesophilic systems while, under mesophilic conditions phenolic compounds reduction was 10% higher compared to the thermophilic systems.

Molecular characterization of cyanobacterial diversity and yearly fluctuations of Microcystin loads in a suburban Mediterranean Lake (Lake Pamvotis, Greece).

Cyanobacterial blooms are a frequent phenomenon in eutrophic freshwaters worldwide, and are considered as potential hazards to ecosystems and human health, while it has been shown that on average 60% of these cyanobacterial blooms are toxic. Hepatotoxic blooms are more common than neurotoxic ones and microcystins have been found to be the most prevalent cyanobacterial hepatotoxins. Lake Pamvotis is an ancient (having been in continual existence throughout the Plio-Pleistocene period) suburban Mediterranean Lake used for recreation, fishing and irrigation purposes which has suffered eutrophication for the last three decades. We investigated cyanobacterial species composition and microcystin loads in this lake over a 16-month period. The highest microcystin concentrations were recorded in autumn, one to two months after the midsummer severe bloom. With the exception of the winter months, microcystin concentrations exceed the WHO upper limits for drinking water but not for recreational waters. Seasonal changes of microcystin bioaccumulation in edible species were also investigated. Microcystin concentrations never exceed the WHO upper limits in those species with the exception of bivalves. For a detailed characterization of the cyanobacterial species composition of the lake, we used polymerase chain reaction (PCR) amplification of the internal transcribed spacer (ITS) between 16S and 23S rRNA genes, in combination with denaturing gradient gel electrophoresis (DGGE). ITS sequences from Lake Pamvotis revealed that the cyanobacterial community of this lake is made of two major populations. A population well defined both microscopically and molecularly as Microcystis sp. dominated during autumn, and another population of filamentous cyanobacteria microscopically characterized as Anabaena sp./Aphanizomenon sp. dominated during midsummer blooms. Sequences of filamentous cyanobacteria from Lake Pamvotis revealed that this cyanobacterial population is homogeneous, although divergent from other populations worldwide. Finally, by using a combination of general and genus specific primer sets against the mcyE gene, we identified Microcystis as the only genus responsible for microcystin production in Lake Pamvotis.

Quality assessment of composts in the Greek market: the need for standards and quality assurance.

An extensive data survey and study of the Greek market for composts or products marketed as such was carried out in order to acquire a comprehensive image of the local situation, in view of the proposed operation of large municipal solid waste (MSW) composting facilities and EU legislation changes. Physical and chemical parameters (moisture, organic matter, electrical conductivity, pH and heavy metals), stability indicators (self-heating potential, germination index) and biological indicators (microbial population, pathogen indicators and selected pathogens) were analyzed for the assessment of product quality. Results revealed wide variations even within the same group of products, which is particularly significant for parameters directly related to environmental protection and public health. The heavy metal content ranged from levels exceeding the fairly lenient Greek standards to below the stringent limits for A+ class compost in Austria. About 25% of the composts examined met the heavy metal limits for the EU eco-label award. Salmonella spp. was not detected in any of the composts but Staphylococcus aureus and Clostridium perfringens were found in 17 and 96% of the composts respectively. Pathogen indicator microorganisms were present at levels above suggested limits in all the composts. The high variability of such important parameters in composts available on the Greek market suggests an urgent need for establishing quality assurance procedures and mechanisms in the country. Moreover, the wide range of limit values within EU member states suggests the need for developing EU compost quality standards, in order to harmonize the compost markets.

Phase-transfer catalytic determination of phenols as methylated derivatives by gas chromatography with flame ionization and mass-selective detection.

A convenient method for the GC determination of phenols as methylated derivatives is proposed, taking advantage of the beneficial features of phase-transfer catalysis (PTC). The optimal experimental conditions of pH, temperature, organic solvent, time of extraction-derivatization and amounts of the participating reactants and catalysts, were properly established. Several catalysts in soluble or polymer-bound form were tested. Most of them demonstrated appreciably high-performance characteristics but the polymer-bound catalyst is most favourable due to its facile separation from the rest of the reaction system after the extraction-derivatization. Interferences with the extraction and derivatization yield were not noticed. The chromatographic separation of 11 methylated derivatives of phenols was complete within 23 min. The detection limits of the method, which range from 0.005 to 0.120 microg, are inadequate for drinking water analysis. However, the method was successfully applied to the analysis of fortified composite lake water samples using GC-flame ionization detection and GC-MS in the single ion monitoring mode with the most abundant characteristic ions. Spiked recoveries of phenolics were in the range 94-102%, on the basis of distilled water calibration graph, signifying that PTC determination of phenols is not affected by the composition of such matrices.