Municipal wastewater treatment by a periodic biofilter with granular biomass.

The paper reports the results obtained during an experimental campaign aimed at transferring aerobic granulation to a demonstrative SBBGR system (i.e., a submerged biofilter that operates in a "fill and draw" mode) for the treatment of municipal wastewater by financial support of the European Commission, within the framework of Life-Environment Programme (PERBIOF Project; www.perbiof-europe.com). The results show that following the generation of granular biomass during the start-up period, the SBBGR was able to remove 80-90% of COD, total suspended solids and ammonia occurring in primary effluent from a municipal wastewater treatment plant even when the minimum hydraulic residence time (i.e., 4 h) was investigated. The process was characterised by a sludge production almost one magnitude order lower than commonly reported for conventional treatment plants. The granular biomass was characterised by a high density (i.e., 150 gTSS/L(biomass)) that allowed a biomass concentration as high as 35 kgTSS/m(3)(bed) to be achieved. Proteobacteria were found as main microbial components of the granular biomass by applying Fluorescence In Situ Hybridization (FISH). No significant changes in microbial composition were observed during reactor operation.

Comparison of different types of landfill leachate treatments by employment of nontarget screening to identify residual refractory organics and principal component analysis.

Three different chemical oxidation processes were investigated in terms of their capability to degrade organic chemical components of real mature landfill-leachate in combination with biological treatment run in a Sequencing Batch Biofilter Granular Reactor (SBBGR). H2O2, H2O2 + UV and O3 were integrated with SBBGR and respective effluents were analyzed and compared with the effluent obtained from biological SBBGR treatment alone. In agreement with their respective oxidative power, conventional bulk parameters (residual COD, TOC, Ntot, TSS) determined from the resulting effluents evidenced the following efficacy ranking for degradation: SBBGR/O3 > SBBGR/UV + H2O2 > SBBGR/H2O2 > SBBGR. A more detailed characterization of the organic compounds was subsequently carried out for the four treated streams. For this, effluents were first subjected to a sample preparation step, allowing for a classification in terms of acidic, basic, strongly acidic and strongly basic compounds, and finally to analysis by liquid chromatography/high resolution mass spectrometry (LC/HR-MS). This classification, combined with further data post-processing (non-target screening, Venn Diagram, tri-dimensional plot and Principal Component Analysis), evidenced that the SBBGR/H2O2 process is comparable to the pure biological oxidation. In contrast, SBBGR/O3 and SBBGR/UV + H2O2 not only resulted in a very different residual composition as compared to SBBGR and SBBGR/H2O2, but also differ significantly from each other. In fact, and despite of the SBBGR/O3 being the most efficient process, this treatment remained chemically more similar to SBBGR/H2O2 than to SBBGR/UV + H2O2. This finding may be attributable to different mechanism of degradation involved with the use of UV radiation. Apart from these treatment differences, a series of recalcitrant compounds was determined in all of the four treatments and partly identified as hetero-poly-aromatic species (humic acids-like species).

Gross parameters prediction of a granular-attached biomass reactor by means of multi-objective genetic-designed artificial neural networks: touristic pressure management case.

The Artificial Neural Networks by Multi-objective Genetic Algorithms (ANN-MOGA) model has been applied to gross parameters data of a Sequencing Batch Biofilter Granular Reactor (SBBGR) with the aim of providing an effective tool for predicting the fluctuations coming from touristic pressure. Six independent multivariate models, which were able to predict the dynamics of raw chemical oxygen demand (COD), soluble chemical oxygen demand (CODsol), total suspended solid (TSS), total nitrogen (TN), ammoniacal nitrogen (N-NH4 (+)) and total phosphorus (Ptot), were developed. The ANN-MOGA software application has shown to be suitable for addressing the SBBGR reactor modelling. The R (2) found are very good, with values equal to 0.94, 0.92, 0.88, 0.88, 0.98 and 0.91 for COD, CODsol, N-NH4 (+), TN, Ptot and TSS, respectively. A comparison was made between SBBGR and traditional activated sludge treatment plant modelling. The results showed the better performance of the ANN-MOGA application with respect to a wide selection of scientific literature cases.

Landfill wall revegetation combined with leachate recirculation: a convenient procedure for management of closed landfills.

There is a need for a reliable sustainable option to effectively manage the landfill leachate generation. This study presents a simple procedure for the revegetation of the walls of closed landfills, employing the leachate as a fertirrigant. The native plants Lepidium sativum, Lactuca sativa, and Atriplex halimus, which suit the local climate, were chosen for this study in Southern Italy. The methodology was structured into three phases (i) early stage toxicity assessment phase (apical root length and germination tests), (ii) adult plant resistance assessment phase, and (iii) soil properties verification phase. The rationale of the proposed approach was first to look at the distinctive qualities and the potential toxicity in landfill leachates for fertigation purposes. Afterwards, through specific tests, the plants used were ranked in terms of resistance to the aqueous solution that contained leachate. Finally, after long-term irrigation, any possible worsening of soil properties was evaluated. The results demonstrated the real possibility of using blended leachate as a fertigant for the revegetation of the walls of closed landfills. In particular, the plants maintained good health when leachate was blended at concentrations of lower than 25 and 5%, respectively for A. halimus and Lepidium sativum. Irrigation tests showed good resistance of the plants, even at dosages of 112 and 133.5 mm m(-2), at maximum concentrations of 25 and 5%, respectively, for A. halimus and Lepidium sativum. The analysis of the total chlorophyll content and of aerial parts dried weight confirmed the results reported above.