Strategies to Suppress Hydrogen-Consuming Microorganisms Affect Macro and Micro Scale Structure and Microbiology of Granular Sludge

Treatment of anaerobic granules with heat and two chemical treatments, contacting with 2-bromoethanesulfonate (BES) and with BESþChloroform, were applied to suppress hydrogen-consuming microorganisms. Three mesophilic expanded granular sludge bed (EGSB) reactors— RHeat, RBES, and RBESþChlo—were inoculated with the treated sludges and fed with synthetic sugar-based wastewater (5 gCOD L 1, HRT 20–12 h). Morphological integrity of granules and bacterial communities were assessed by quantitative image analysis and 16S rRNA gene based techniques, respectively. Hydrogen production in RHeat was under 300mLH2 L 1 day 1, with a transient peak of 1,000 mLH2 L 1 day 1 after decreasing HRT. In RBESþChlo hydrogen production rate did not exceed 300mLH2 L 1 day 1 and there was granule fragmentation, release of free filaments from aggregates, and decrease of granule density. In RBES, there was an initial period with unstable hydrogen production, but a pulse of BES triggered its production rate to 700 200mLH2 L 1 day 1. This strategy did not affect granules structure significantly. Bacteria branching within Clostridiaceae and Ruminococcaceae were present in this sludge. This work demonstrates that, methods applied to suppress H2-consuming microorganisms can cause changes in the macro- and microstructure of granular sludge, which can be incompatible with the operation of high-rate reactors.European Community fund FEDER Contract grant number: FCOMP-01-0124-FEDER-007087; PTDC/BIO/69745/2006; SFRH/ BD/29823/2006; SFRH/BD/48965/2008Fundação para a Ciência e a Tecnologia (FCT

Pollutant footprint analysis for wastewater management in textile dye houses processing different fabrics

BACKGROUND: This study investigated the water and pollution footprints of a dye house, which processed cotton knits, polyester (PES) knits and PES-viscose woven fabrics. Experimental evaluation was carried out for each processing sequence. Variations in wastewater flow and quality were established as a function of the production program in the plant. A model evaluation of wastewater dynamics was performed and defined specifications of an appropriate treatment scheme. RESULTS: The plant was operated with a capacity of 4300 t year−1 of fabric, which generated a wastewater flow of 403 500m3 year−1 and a COD load of 675 t year−1. The overall wastewater footprint of the plant was computed as 91m3 t−1 and the COD footprint as 160 kg t−1 of fabric. Depending on the fabric type, results indicated expected changes in wastewater flow between 600 and 1750m3 day−1 in COD load between 1470 and 2260 kg day−1 and in COD concentration between 1290 and 3400mgL−1. CONCLUSION: A model simulation structured upon COD fractionation and related process kinetics revealed partial removal of slowly biodegradable COD, coupled with high residual COD, which would by-pass treatment. Resulting biodegradation characteristics necessitated an extended aeration system, which could also enable partial breakdown of residual COD. Effluent COD could be reduced to 220–320mgL−1 with this wastewater management strategy. © 2018 Society of Chemical Industr

Recent invasion by a non-native cyprinid (common bream Abramis brama) is followed by major changes in the ecological quality of a shallow lake in southern Europe

We present an example of how an invasion by a non-native cyprinid (common bream, Abramis brama (Pisces: Cyprinidae), hereafter bream) in a natural shallow lake in southern Europe (Lake Montorfano, northern Italy) may have adversely affected the state of the lake’s ecosystem. In less than two decades, bream became the most abundant species and characterized by a stunted population with asymptotic length 33.5 cm, an estimated mean length at first maturity of 19.6 cm, a total mortality rate of 0.64 year−1 and a diet overwhelmingly dominated by microcrustaceans. Following bream establishment, nutrients and phytoplankton biomass rose, the proportion of Cyanobacteria by numbers increased markedly and water transparency decreased. Total zooplankton abundance increased with a marked increase in small cladocerans and copepods, whereas the abundance of large herbivorous cladocerans did not change. The coverage of submerged macrophytes declined, as did the abundance of native pelagic zooplanktivorous fish. The composition of the fish community shifted towards a higher proportion of zoobenthivorous species, such as bream and pumpkinseed (Lepomis gibbosus). Our results indicate that bream affected water quality through bottom-up mechanisms, while top-down effects were comparatively weak. Selective removal of bream and perhaps stocking of native piscivores might improve the ecological status of the lake