Investigations of biological processes in Austrian MBT plants

Mechanical biological treatment (MBT) of municipal solid waste (MSW) has become an important technology in waste management during the last decade. The paper compiles investigations of mechanical biological processes in Austrian MBT plants. Samples from all plants representing different stages of degradation were included in this study. The range of the relevant parameters characterizing the materials and their behavior, e.g. total organic carbon, total nitrogen, respiration activity and gas generation sum, was determined. The evolution of total carbon and nitrogen containing compounds was compared and related to process operation. The respiration activity decreases in most of the plants by about 90% of the initial values whereas the ammonium release is still ongoing at the end of the biological treatment. If the biogenic waste fraction is not separated, it favors humification in MBT materials that is not observed to such extent in MSW. The amount of organic carbon is about 15% dry matter at the end of the biological treatment.     

Effects of environmental parameters on the oxygen consumption of four marine invertebrates: a comparative factorial study

The oxygen consumption curves of two decapod crustaceans (Palaemon serratus, Penaeus monodon) and two prosobranch molluscs (Trunculariopsis trunculus, Nassarius mutabilis) have been detected in the entire pO₂ interval from 0 to 160 mmHg, under different conditions of temperature and salinity. From the experimental curves, physiological parameters such as the initial oxygen consumption velocity, the Q ₁₀ values and the oxygen independence indices have been measured. The latter parameters have been obtained using normalised plots which allow their better evaluation. The effects of temperature, salinity and oxygen partial pressure on the oxygen-consumption features have been studied using a factorial experimental plan which allows measurement of the effects of each experimental variable as well as the effects of synergistic interactions between different variables. Received: 27 March 2000 / Accepted: 13 November 2000     

Trail and recruitment pheromones in Camponotus socius (Hymenoptera: Formicidae)

Summary. Worker ants of Camponotus socius employ multicomponent signals during group recruitment to food sources and nest emigrations. The chemical signals consist of trail orientation pheromones that originate from the hindgut. Two components that elicit trail orientation behavior were identified: (2S,4R,5S)-2,4-dimethyl-5-hexanolide and 2,3-dihydro-3,5-dihydroxy-6-methylpyran-4-one. Although both compounds release trail following behavior, in choice tests the former compound is preferred significantly. The major recruitment signal appears to be formic acid discharged from the poison gland. Compounds identified in the Dufour gland secretions do not seem to be involved in the recruitment process.     

Spray mechanism of crepidogastrine bombardier beetles (Carabidae; Crepidogastrini)

Summary.   The defensive glandular apparatus of primitive bombardier beetles of the tribe Crepidogastrini (Carabidae) is described for the first time. As exemplified by two African species (Crepidogaster ambreana and C. atrata), the apparatus conforms to the basic bombardier plan, in that the glands are bicompartmented and the secretion is quinonoid (it contains 1,4-benzoquinones and hydrocarbons), hot, and discharged audibly. In a number of morphological respects the crepidogastrine apparatus resembles that of the classical bombardiers of the tribe Brachinini (rather than that of bombardiers of the paussoid lineage), reinforcing the view, already held on taxonomic grounds, that the Crepidogastrini and Brachinini are closely related. That the Crepidogastrini may be primitive relative to Brachinini is underscored by the finding that, unlike brachinines, crepidogastrines do not pulse their secretory emissions. Moreover, they discharge their secretion as a mist, rather than forcibly in the form of jets. Received 22 May 2001; accepted 29 May 2001.     

Trace-metal detoxification in the ventral caeca of Orchestia gammarellus (Crustacea: Amphipoda)

The talitrid amphipod crustacean Orchestia gammarellus (Pallas) was collected from metal-contaminated (Dulas Bay, Gironde) and control (Millport) sites in the UK and France. Irrespective of site of origin, the amphipods showed the same physiological mechanism of trace-metal detoxification, involving the ventral caeca. Copper was always present in lysosomal residual bodies in the ventral caeca. Following laboratory exposure to zinc and cadmium, the lysosomes usually contained both copper and zinc but cadmium was not detectable. The lysosomal copper concentration is positively correlated to that of sulphur, while the concentration of lysosomal zinc is related to that of phosphorus. Results are interpreted in terms of the differential rates of turnover of metallothioneins chelating copper, zinc or cadmium. Received: 9 February 1999 / Accepted: 2 December 1999     

Response of foodborne Salmonella spp. marker strains inoculated on egg shell surfaces to disinfectants in a commercial egg washer.

The objective of this study was to determine the effectiveness of an iodine based disinfectant (IBD, Iocide, Biomedical Development Corporation, San Antonio, TX) on Salmonella enteritidis and S. typhimurium inoculated on egg shell surfaces under simulated industry egg processing conditions with a commercial egg washer used as the sanitizer delivery system. Re-circulated egg washer water containing 1.40-2.85 g/l total dissolved solids was obtained from a commercial egg processing. Sanitizing treatments consisted of distilled deionized water (DDW), IBD, and chlorine (CL; 200 ppm). All treatments (DDW, IBD and CL) significantly (p < 0.05) decreased Salmonella spp. populations on the shell compared to dry (no spray) egg controls. However, efficacy of egg sanitizers appeared to be dependent on the level of total dissolved solids in the egg wash water.     

Composition and management of rechargeable electric torch wastes in Ibadan,Nigeria

The consumption, disposal, material and chemical compositions of rechargeable electric torch wastes (RETWs) were investigated in Ibadan, Nigeria. Twenty-five RETWs of ten models were collected and disassembled. Their battery electrodes (BEs) and printed circuit boards (PCBs) were acid digested and leached using United States Environmental Protection Agency (USEPA) method 3050B and USEPA Method 1311, respectively. The digests and extracts were analysed for total and extractable Pb, Cd, Cr and Ni using atomic absorption spectrophotometer. The US Test method (CPSC-CH-E 1002-08) was used for digestion of the plastic components. Two hundred questionnaires were distributed to users in Ibadan to determine their usage of RETs and their management when spent. The results indicated that BEs contributed the highest percentage (44 %) component, followed by plastic (38 %). Other components include metal, PCBs, glass and wire. Of the respondents, 61.9 % dispose their spent torches in dumpsites. The mean ± SD concentrations of Pb, Cd, Cr and Ni in the BEs were 500 ± 109 g/kg, 3.94 ± 6.84 mg/kg, 0.33 ± 0.88 mg/kg, 1.68 ± 0.74 mg/kg respectively; in the PCBs, they were 684 ± 42 g/kg, 13.7 ± 17.8 mg/kg, 13.5 ± 10.2 mg/kg and 193 ± 437 mg/kg; and in the plastics, they were 14.1 g/kg, 5.33 mg/kg, 17 mg/kg, and 4.67 mg/kg respectively. The extractable Pb in BE (2670 mg/L) and PCBs (235 mg/L) exceeded the Toxicity Characteristics Leaching Procedure (TCLP) limit of 5 mg/L. RETWs present potential environmental problems in the absence of effective recycling.