Search results for "Submerged"
showing 10 items of 47 documents
Diploid Ruppia cirrhosa populations from a southern Mediterranean shallow system
2016
Abstract This paper focuses on the morphology and karyology of representative Ruppia populations from a southern Mediterranean shallow system. The cosmopolitan genus Ruppia L. generally inhabits shallow waters such as coastal lagoons and brackish habitats. Ruppia species are characterised by a simplified morphology and high intraspecific phenotypic plasticity. The chromosome number of Sicilian Ruppia populations is reported here for the first time. The analysed populations showed morphological and reproductive characters of Ruppia cirrhosa (Petagna) Grande but a diploid cytotype (2n = 20). A low fruit production was also observed, suggesting that vegetative reproduction is the main reproduc…
A new strategy to maximize organic matter valorization in municipalities: combination of urban wastewater with kitchen food waste and its treatment w…
2017
[EN] The aim of this study was to evaluate the feasibility of treating the kitchen food waste (FW) jointly with urban wastewater (WW) in a wastewater treatment plant (WWTP) by anaerobic membrane technology (AnMBR). The experience was carried out in six different periods in an AnMBR pilot-plant for a total of 536 days, varying the SRT, HRT and the food waste penetration factor (PF) of food waste disposers. The results showed increased methane production of up to 190% at 70 days SRT, 24 hours HRT and 80% PF, compared with WW treatment only. FW COD and biodegradability were higher than in WW, so that the incorporation of FW into the treatment increases the organic load and the methane producti…
Design methodology for submerged anaerobic membrane bioreactors (AnMBR): A case study
2015
[EN] The main objective of this study is to propose guidelines for designing submerged anaerobic MBR (AnMBR) technology for municipal wastewater treatment. The design methodology was devised on the basis of simulation and experimental results from an AnMBR plant featuring industrial-scale hollow-fibre membranes. The proposed methodology aims to minimise both capital expenditure and operating expenses, and the key parameters considered were: hydraulic retention time, solids retention time, mixed liquor suspended solids concentration in the membrane tank, 20 C-standardised critical flux, specificgas demand per square metre of membrane area, and flow of sludge being recycled from the membrane …
Chara hispida beds as a sink of nitrogen: Evidence from growth, nitrogen uptake and decomposition
2007
8 pages, and tables stadistics, and figures.
Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent
2012
This study investigated the removal of nitrogen and phosphorus from the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) by means of a lab-scale photobioreactor in which algae biomass was cultured in a semi-continuous mode for a period of 42 days. Solids retention time was 2 days and a stable pH value in the system was maintained by adding CO2. Nitrogen and phosphorus concentrations in the SAnMBR effluent fluctuated according to the operating performance of the bioreactor and the properties of its actual wastewater load. Despite these variations, the anaerobic effluent proved to be a suitable growth medium for microalgae (mean biomass productivity was 234 mgl(-1) d(-1)), achie…
Isoëtes sabatina (Isoëtaceae, Lycopodiopsida). Taxonomic distinctness and preliminary ecological insights
2021
1) Isoëtes sabatina is the rarest aquatic quillwort in Europe. Although recently found (2013) in Lake Bracciano (central Italy), the species is just one step away from extinction with an estimated population not exceeding 400 individuals and a spatial range of a few hundred square metres. 2) Lake Bracciano is a deep, oligo-mesotrophic Mediterranean volcanic lake that has been subjected to human activities. From January to October 2017, the lake experienced a dramatic water level decrease (up to −1.50 m), which significantly affected the littoral zone and the habitat of I. sabatina. 3) To improve the chances of survival of I. sabatina, the first eco-taxonomic investigation on this species wa…
Designing an AnMBR-based WWTP for energy recovery from urban wastewater: The role of primary settling and anaerobic digestion
2015
The main objective of this paper is to assess different treatment schemes for designing a submerged anaerobic membrane bioreactor (AnMBR) based WWTP. The economic impact of including a primary settling (PS) stage and further anaerobic digestion (AD) of the wasted sludge has been evaluated. The following operating scenarios were considered: sulphate-rich and low-sulphate urban wastewater (UWW) treatment at 15 and 30 ºC. To this aim, the optimum combination of design/operating parameters that resulted in minimum total cost (CAPEX plus OPEX) for the different schemes and scenarios was determined. The AnMBR design was based on both simulation and experimental results from an AnMBR plant featuri…
Instrumentation, control, and automation for submerged anaerobic membrane bioreactors
2015
A submerged anaerobic membrane bioreactor (AnMBR) demonstration plant with two commercial hollow-fibre ultrafiltration systems (PURON® , Koch Membrane Systems, PUR-PSH31) was designed and operated for urban wastewater treatment. An instrumentation, control, and automation (ICA) system was designed and implemented for proper process performance. Several single-input-single-output (SISO) feedback control loops based on conventional on off and PID algorithms were implemented to control the following operating variables: flow-rates (influent, permeate, sludge recycling and wasting, and recycled biogas through both reactor and membrane tanks), sludge wasting volume, temperature, transmembrane pr…
Global sensitivity analysis of a filtration model for submerged anaerobic membrane bioreactors (AnMBR)
2014
The results of a global sensitivity analysis of a filtration model for submerged anaerobic MBRs (AnMBRs) are assessed in this paper. This study aimed to (1) identify the less- (or non-) influential factors of the model in order to facilitate model calibration and (2) validate the modelling approach (i.e. to determine the need for each of the proposed factors to be included in the model). The sensitivity analysis was conducted using a revised version of the Morris screening method. The dynamic simulations were conducted using long-term data obtained from an AnMBR plant fitted with industrial-scale hollow-fibre membranes. Of the 14 factors in the model, six were identified as influential, i.e…
Mathematical modelling of filtration in submerged anaerobic MBRs (SAnMBRs): long-term validation
2013
The aim of this study was the long-term validation of a model capable of reproducing the filtration process occurring in a submerged anaerobic membrane bioreactor (SAnMBR) system. The proposed model was validated using data obtained horn a SAnMBR demonstration plant fitted with industrial-scale hollow-fibre membranes. The validation was carried out using both lightly and heavily fouled membranes operating at different bulk concentrations, gas sparging intensities and transmembrane fluxes. Across a broad spectrum of operating conditions, the model correctly forecast the respective experimental data in the long term. The simulation results revealed the importance of controlling irreversible f…