A comprehensive study on coagulant performance and floc characterization of natural Cassia obtusifolia seed gum in treatment of raw pulp and paper mill effluent

Pulp and paper industry generates 30–180 m3 of wastewater per ton of manufactured pulp and 20–70 m3 of wastewater per ton of manufactured paper and paperboard. Coagulation process is widely applied as a pre-treatment or primary treatment to remove suspended solids from industrial effluent including pulp and paper mill effluent (PPME). Nevertheless, the excessive use of inorganic coagulants, such as alum, poses deleterious environmental impacts and risks to living organisms include low biodegradability, increase of metal content in discharged effluent and generation of toxic sludge. In view of this, the present study investigated the potential use of natural Cassia obtusifolia seed gum in treatment of raw and undiluted PPME through coagulation process. Recommended conditions (initial pH 5, 0.75 g/L dosage, 10 rpm and 10 min slow-mixing, and 1 min settling time) allowed C. obtusifolia gum removed high total suspended solids and chemical oxygen demand up to 86.9 and 36.2%, respectively. Findings from the present study showed that the coagulation efficiency using C. obtusifolia gum was comparable to alum. Also, characterizations showed that C. obtusifolia gum, alum and their flocs possessed distinctive features. The difference in peak occurrence from Fourier-transform infrared spectroscopy analysis indicated that the mechanism of floc formation using C. obtusifolia gum and alum differed. Besides, dissimilar thermal decomposition stages were observed for C. obtusifolia gum and alum through thermogravimetric analysis. Scanning electron microscope images showed that flocs formed using C. obtusifolia gum was highly fibrous-like and aggregate, whereas irregularly-shaped and aggregate for alum. In conclusion, C. obtusifolia gum could be served as a promising alternative to alum as a natural coagulant in treatment of PPME

Investigation of the Climatic and Environmental Context of Hendra Virus Spillover Events 1994–2010

Hendra virus is a recently emerged bat-borne zoonotic agent with high lethality in horses and humans in Australia. This is a rare disease and the determinants of bat to horse transmission, including the factors that bring these hosts together at critical times, are poorly understood. In this cross-disciplinary study climatic and vegetation primary productivity variables are compared for the dispersed and heterogenic 1994–2010 outbreak sites. The significant occurrence of spillover events within the dry season (p =  0.013, 95% CI (0.57–0.98)) suggests seasonal forcing of transmission across species, or seasonal forcing of virus excretion by the reservoir host. We explore the evidence for both. Preliminary investigations of the spatial determinants of Hendra disease locations are also presented. We find that postal areas in the Australian state of Queensland in which pteropid fruit bat (flying fox) roosts occur are approximately forty times more likely (OR = 40.5, (95% CI (5.16, 317.52)) to be the location of Hendra spillover events. This appears to be independent of density of horses at these locations. We consider issues of scale of host resource use, land use change and limitations of existing data that challenge analysis and limit further conclusive outcomes. This investigation of a broad range of potential climatic and environmental influences provides a good base for future investigations. Further understanding of cross-species Hendra virus transmission requires better understanding of flying fox resource use in the urban-rural landscape

Research highlights: Invasive plant and animals research 2022 - 23 / Department of Agriculture and Fisheries, Queensland

This document summarises the 2022–23 program of the Invasive Plants and Animals research group in Biosecurity Queensland. Our applied research program aims to better manage Queensland’s worst weeds and pest animals, reducing their impacts on agriculture, the environment and the community. Our work is undertaken at four centres across the state: • Ecosciences Precinct, Dutton Park • Pest Animal Research Centre, Toowoomba • Tropical Weeds Research Centre, Charters Towers • Tropical Weeds Research Centre, South Johnstone. We also collaborate with numerous Queensland, interstate and overseas organisations. Higher degree students are supported to work on several research projects in weed and pest animal management. The research projects summarised in this document cover the development of effective control strategies and methods (e.g. biological control and herbicides), as well as improved knowledge of pest species’ biology and assessment of pest impact