The success of the UASB reactor depends largely on the settling properties and stability of the sludge bed which comprises the anaerobic active biomass. The solid-liquid separation behaviour of the sludge bed in 2 UASB reactors (R1 at 35 o C and R2 at 20 o C) fed with primary sewage sludge and sulphate was investigated because this appeared to be a retention timedefining feature of the system. Consequently, the settling rate of the various solids fractions in the sludge was measured in a settleometer to determine if bed expansion or sludge settleability was the capacity-limiting process. It was found that both sludges settled well and at an upflow velocity of up to 1.16 m/h 99% of the total sludge mass was retained. This upflow velocity was 9.1 and 13.7 times higher than the maximum operating upflow velocity of UASB reactors R1 (0.127 m/h) and R2 (0.085 m/h) respectively that caused system failure. Tests were also done to demonstrate the effect of upflow velocity (V up ) on the sludge bed expansion. Relative to the settled sludge volume at zero upflow, the R1 sludge expanded 1.8 times at a V up of 0.127 m/h while R2 sludge expanded 2.0 times at a V up 0.085 m/h. From the tests, R1 (35 o C) sludge had a better settleability and expanded less compared to R2 (20 o C) sludge for the same applied upflow velocity. Because in operating R1 and R2, the bed volume was kept constant, the mass of sludge removed from the system correspondingly increased as upflow increased and the bed expanded, causing a reduced sludge age and sludge bed mass to mediate the bioprocesses. It was concluded that the system failure was caused by bed expansion rather than by the sludge settleability.

Fourteen juvenile scalloped hammerhead sharks ( Sphyrna lewini ; SHS) were captured between November and December 2014 in the Rewa Delta in Fiji, and assessed for intestinal microflora characterisation using 16S rRNA amplicon sequencing by Illumina Miseq. The microbial population revealed a fluctuating dominance between the Enterobacteriaceae and Vibrionaceae families, namely Citrobacter and Photobacterium spp. Other related marine operational taxonomic units were closely related to Afipia felis , Chloroflexus aggregans , Psychrobacter oceani , Pontibacter actiniarum and Shigella sonnei . Two sharks had distinctive profiles that were dominated by known pathogens, namely Aeromonas salmonicida and Klebsiella pneumonia . The presence of a Methanosaeta species, and of Shigella and Psychrobacter , would suggest sewage contamination because of a spill that occurred on the 6 th of December 2014. This study successfully establishes a baseline for future research.

This paper describes a novel system for the biological sulphate reduction (BSR) of acid mine drainage (AMD) using primary sewage sludge (PSS) as carbon source in an upflow anaerobic sludge bed (UASB) reactor configuration. A UASB reactor was operated at a temperature of 35 o C and it received PSS (1 875 mgCOD/ℓ) augmented with sulphate (1 500 mgSO 4 2-/ℓ). The experimental results indicate that high treatment efficiency was achieved at more than 90% sulphate reduction at a liquid hydraulic retention time (HRT) of 13.5 h. In this study, the effects of various operational parameters were also investigated. The effect of a biomass recycle stream from the top to the bottom of the sludge bed was found to initiate rapid BSR from the bottom of the bed. Profile tests showed that effective and immediate sulphate reduction was achieved as soon as the influent entered the reactor. From these results, it can be concluded that the UASB configuration using PSS as energy source would be a viable method for the BSR of AMD.

The use of the conventional COD method to measure sulphide proved to be problematic due to the loss of hydrogen sulphide (H 2 S) during sample handling. For calibration of models based on mass balances, and operation of full-scale systems, it was imperative to develop simple wet chemistry analytical procedures for the accurate measurement of parameters like sulphide, COD, alkalinities and VFA in order to monitor BSR systems and achieve 100% COD and S mass balances. Three different analytical methods were investigated to minimise the loss of un-dissociated H 2 S. Method 1, which is the recommended Standard Methods COD test method, resulted in poor S mass balance (64-75%) due to loss of H 2 S during sample handling, mainly vacuum filtration. Method 2, in which 3 drops of 10 M NaOH are added immediately upon effluent sample collection to raise the pH to > 10 and converting un-dissociated H 2 S species into the HSspecies resulted in minimal sulphide loss during sample vacuum filtration, dilution, mixing and standing. Method 3, in which a polyelectrolyte is added to the effluent sample to coagulate the organic particles with centrifugation for solid-liquid separation instead of vacuum filtration. Results from Method 3 showed an improvement in the S mass balance with respect to Method 1-91% against 75% without a long sample standing period and 88% against 65% with a long sample standing period. However, S mass balance with Method 3 was still relatively low when compared with Method 2 (86 to 91% against 92 to 95%). Therefore, Method 2 was the best simple wet chemistry analytical procedure to accurately measure S T (= H 2 S + HS-) and achieve close to 100% COD and S mass balances. The effects of S T loss were also investigated on the total and subsystem alkalinities as determined with the 5-pH point titration method. By testing standard solutions with known carbonate, acetate and sulphide species and upflow anaerobic sludge bed (UASB) reactor effluent samples, it was found that the total alkalinity concentration is not affected by H 2 S (and CO 2) loss as the subsystem alkalinities re-speciate due to a change in pH; and to obtain accurate H 2 CO 3 * alk and volatile fatty acid (VFA) concentrations, accurate sulphide concentrations are required, i.e. those obtained from Method 2.

Coal seam gas (CSG) is a new major export for Australia. The production of CSG releases a significant amount of brackish water to the surface, known as associated water. Queensland’s Department of Environment and Heritage Protection (DEHP) has predicted that the peak yearly flow of the associated water could range between 100-280 gigalitres (GL) per year. This presents a major challenge to the CSG industry in water and its by-product (brine) management. CSG water quality varies across regions, but is typically high in total dissolved solids, bicarbonate, hardness, and silica. Consequently, CSG water without treatment is unsuitable for beneficial uses. To date, reverse osmosis (RO) desalination processes with suitable pre-treatment steps have been employed to remove elevated salts and other compounds before CSG water can be used beneficially. One type of beneficial reuse of the treated water that has gained acceptance and prominence in recent times is the irrigation of agricultural crops and forestry. RO brine, a highly saline stream, requires a managed response to ensure a socially, environmentally and financially sound outcome. Conventional evaporation in brine ponds is not considered favourably under existing government directions and, consequently, alternative solutions are sought. Thermal processes, such as brine concentrators, have been used in the treatment of CSG RO brine. The resulting high-quality distillate produced by thermal processes can be used in a number of applications along with a greater proportion of water recovered from such processes. This peer-reviewed paper concludes that a thermal process in conjunction with a high-recovery RO membrane plant, configured as a hybrid membrane/thermal configuration, is probably a suitable solution to meet policy direction by improving system recovery as a precursor to advance associated water treatment and brine management. The discussion is generated out of MWH’s experience with CSG water treatment and management processes, which totals a number of significant projects in the CSG industry.