Search results for "sewage"

Electrodialysis for wastewater treatment-part II: Industrial effluents

2020

Abstract Electrodialysis and related processes have huge potential in the treatment of effluents from a variety of industrial processes. They can recover water and other valuable products, including heavy metal ions, acids and bases, nutrients, and organics. In recent years, novel and improved systems have been continuously developed as a result of research in the field, showing that the (near) zero liquid discharge approach can be affordable in several industrial applications. A larger market share is expected in the near future.

Ultrafiltration as a Means to Investigate Copper Resistance Mechanisms in Soil Bacteria

1999

Copper is a trace element of major concern for agricultural soils. It exhibits a high toxicity against microorganisms and is widely introduced into soils as a component of pesticide treatments or urban wastes such as sewage sludges or refuse composts. In most French vineyards, “Bordeaux mixture” (copper sulfate) has been applied for more than a century, sometimes leading to copper concentrations in soils much higher than the threshold values (100 mg kg−1 in France). Microorganisms exposed to high concentrations of copper or other trace elements are known to develop resistance mechanisms and represent a suitable material for the study of such processes, both at a physiological and molecular …

Copper Dynamics and Impact on Microbial Communities in Soils of Variable Organic Status

2008

International audience; The effect of soil organic status on copper impact was investigated by means of a microcosm study carried out on a vineyard soil that had been amended with varying types of organic matter during a previous long-term field experiment. Soil microcosms were contaminated at 250 mg Cu kg−1 and incubated for 35 days. Copper distribution and dynamics were assessed in the solid matrix by a sequential extraction procedure and in the soil solution by measuring total and free exchangeable copper concentrations. Copper bioavailability was also measured with a whole-cell biosensor. Modifications of microbial communities were assessed by means of biomass-C measurements and charact…

Modelling hydrolysis: Simultaneous versus sequential biodegradation of the hydrolysable fractions

2018

Hydrolysis is considered the limiting step during solid waste anaerobic digestion (including co-digestion of sludge and biosolids). Mechanisms of hydrolysis are mechanistically not well understood with detrimental impact on model predictive capability. The common approach to multiple substrates is to consider simultaneous degradation of the substrates. This may not have the capacity to separate the different kinetics. Sequential degradation of substrates is theoretically supported by microbial capacity and the composite nature of substrates (bioaccessibility concept). However, this has not been experimentally assessed. Sequential chemical fractionation has been successfully used to define i…

Soil DNA evidence for altered microbial diversity after long-term application of municipal wastewater

2010

International audience; Water resources constitute a social, agricultural and economic problem in most countries of the southern Mediterranean Basin. Alternative strategies have been developed such as the reuse of municipal wastewater for irrigation in agriculture. Despite numerous advantages for soil fertility and crop productivity, recycling wastewater in soils also has several ecotoxicological and sanitary problems. Few investigations have assessed the risk by evaluating the impact of wastewater irrigation on soil microbes. Here, we report for the first time the short- and long-term effects of treated municipal wastewater irrigation on the density and genetic structure of bacterial and f…

Analysis of Organic-Waste-Based Bioenergy Potential in the Russian Federation : potential of substitution of conventionally produced energy with bioe…

2008

Ultrasound assisted method to increase soluble chemical oxygen demand (SCOD) of sewage sludge for digestion

2004

The aim of this study was to clarify the possibilities to increase the amount of soluble chemical oxygen demand (SCOD) and methane production of sludge using ultrasound technologies with and without oxidising agents. The study was done using multivariate data analyses. The most important factors affected were discovered. Ultrasonically assisted disintegration increased clearly the amount of SCOD of sludge. Also more methane was produced from treated sludge in anaerobic batch assays compared to the sludge with no ultrasonic treatment. Multivariate data analysis showed that ultrasonic power, dry solid content of sludge (DS), sludge temperature and ultrasonic treatment time have the most signi…

Disintegration of Wastewater Activated Sludge (WAS) for Improved Biogas Production

2018

Due to rapid urbanization, the number of wastewater treatment plants (WWTP) has increased, and so has the associated waste generated by them. Sustainable management of this waste can lead to the creation of energy-rich biogas via fermentation processes. This review presents recent advances in the anaerobic digestion processes that have led to greater biogas production. Disintegration techniques for enhancing the fermentation of waste activated sludge can be apportioned into biological, physical and chemical means, which are included in this review; they were mainly compared and contrasted in terms of the ensuing biogas yield. It was found that ultrasonic- and microwave-assisted disintegrati…

Environmental assessment of the Sibiu County, Romania: proposal for sewage sludge and OFMSW management

2017

The aim of the work is to assess current solid waste management (SWM) and wastewater treatment (WWT) in the county of Sibiu, Romania. Sibiu is a region where industrialization and tourism are spreading constantly, while pollution monitoring and the introduction of circular economy (CE) principles are still lacking. The environmental issues are mostly due to the absence of reliable sanitation systems, in particular for what concerns sewage sludge treatment. Moreover, Organic fraction from selective collection of municipal solid waste is still missing, since it is disposed of directly to landfill, increasing environmental pollution and contributing considerably to global warming. As a result,…

Influence of the Oxic-Settling-Anaerobic (OSA) Process on Methane Production by Anaerobic Digestion of Sewage Sludge

2023

The present study evaluated different sludge-reduction mechanisms in the oxic-settling-anaerobic (OSA) process in terms of their effects on methane productivity by anaerobic digestion of sewage sludge. Two different layouts were investigated for the sludge return from an anaerobic side-stream reactor (ASSR) to the anoxic (scheme A) or the aerobic (scheme B) reactor of a pre-denitrification plant. Biochemical methane-potential (BMP) assays performed on the excess sludge revealed that scheme A promoted an overall increase of methane production in the OSA (20 mLCH4 gVSS−1d−1, +19%), although compared with a control CAS plant a significant decrease in the excess sludge production (3…