Search results for "sewage"
showing 10 items of 480 documents
Changes in soil redox potential in response to flood irrigation with waste water in central Mexico
2017
Irrigation with untreated sewage water adds fresh organic matter to the soil. When it is applied by flooding, as in the Mezquital Valley of Mexico, many of the pores in the soil become temporarily waterlogged and depleted of oxygen, and reduction generates nitrous oxide (N2O) and methane (CH4). We monitored the redox potential, Eh, in the soil at two sites in the Mezquital Valley to discover whether the short-term gaseous emissions matched the changes in Eh. One site is irrigated periodically by flooding with waste water and has alfalfa, rye grass and maize grown in succession; the other site grows maize with water from summer rain only. Each electrode buried in the soil for the purpose pro…
Seasonal and spatial heterogeneity in the water chemistry of two sewage-affected saline shallow lakes from central Spain
2003
The seasonal features of the water chemistry in the saline shallow lakes Laguna de Manjavacas and Laguna del Pueblo (Castilla – La Mancha, Central Spain) were studied during 1990–1991 and in 1997. These lakes were both affected by sewage inputs driving them to a high trophic status. However, whereas sewage inputs entered Laguna del Pueblo directly, wastewater reached Laguna de Manjavacas after running for 8 km through a small riverbed, where natural processes caused partial mineralisation of organic matter. Moreover, water quality was further improved before entering the main water body of Laguna de Manjavacas, since water crossed through a wetland and high amounts of organic matter and ino…
Heavy metals in sewage sludges contribute to their adverse effects on the arbuscular mycorrhizal fungusGlomus mosseae
2003
Applying sewage sludges to agricultural land is a widespread practice because of the sludges’ agronomic value as a source of plant nutrients and organic matter. Nevertheless, sludges often contain micropollutants that can constitute a menace for health and the environment. Arbuscular mycorrhizal fungi are sensitive to sewage sludges that have been spiked, or not, with metallic trace elements (MTE). Here we have investigated if MTE in sewage sludges could be responsible for effects on mycorrhizal development betweenGlomus mosseae andMedicago truncatula. The impact of a dehydrated or composted urban sewage sludge spiked or not with MTE, was tested on spore germination and root colonization by…
Wastewater COD characterization: analysis of respirometric and physical-chemical methods for determining biodegradable organic matter fractions
2010
BACKGROUND: In this work, a comprehensive study of the respirometric and physical–chemical methods has been performed to evaluate the information provided by these two methodologies in order to assess the biodegradable organic matter fractions of wastewater. RESULTS: First, an analysis was performed of the influence of the initial substrate on biomass ratio (F0/X0) in the assessment of readily biodegradable organic matter, SS, through respirometric experiments. In order to achieve an adequate assessment of the SS component, similar conditions (given by the initial F0/X0 ratio) must be employed in experiments that are carried to determine SS and YH (heterotrophic yield). Second, a comparativ…
DESASS: A software tool for designing, simulating and optimising WWTPs
2008
This paper presents a very useful software tool to design, simulate and optimise wastewater treatment plants. The program is called DESASS (DEsign and Simulation of Activated Sludge Systems) and has been developed by CALAGUA research group. The mathematical model implemented is the Biological Nutrient Removal Model No.1 (BNRM1) which allows simulating the most important physical, chemical and biological processes taking place in treatment plants. DESASS calculates the performance under steady or transient state of whole treatment schemes including primary settlers, volatile fatty acid generation systems by primary sludge fermentation, activated sludge systems for biological organic matter a…
Screening pretreatment methods to enhance thermophilic anaerobic digestion of pulp and paper mill wastewater treatment secondary sludge
2013
Abstract The effect of hydrothermal (150 °C for 10 min and 70 °C for 40 min), enzymatic (Accelerase 1500, 0.07 g/g volatile solids (VS)), ultrasound (45 kHz for 30 min) and chemical pretreatments (HNO3 at pH 3 and NaOH at pH 12) alone or in combination on the chemical composition and methane yield of the pulp and paper mill secondary sludge was studied in batch assays at 55 °C. In total, 12 different pretreatment combinations were compared. Chemical analyses showed that all pretreatments except for HNO3 and ultrasound pretreatments improved the organic matter solubilization. Among the studied pretreatments, hydrothermal (150 °C, 10 min) pretreatment alone or in combination with enzymatic an…
Wastewater modification processes in a stabilization reservoir: a new mathematical model
2018
The paper presents a mathematical model for the simulation of the ecology of a wastewater stabilization reservoir (WSR). WSRs are hypertrophic aquatic systems devoted to water storage in warm countries where shortage conditions are often encountered. Several factors that affect the stabilization reservoir’s effluent quality were taken into account: hydraulics and hydrology, solar radiation, reaeration, algae, zooplankton, organic matter, pathogens, and sediment-water interactions. The model quantifies the specific influence of each factor on effluent quality, and evaluating the correlation between the different factors. State variables included in the model were: algae, dissolved oxygen, or…
Use of biological and sedimentation models for designing Peñíscola WWTP.
2004
This paper presents Peñíscola wastewater treatment plant design. Peñíscola is a tourist city in Castellón (Spain), whose population changes significantly between summer and the rest of the year. The design of the biological and settling treatment units has been confirmed by computer model simulations and provided for biological organic matter, nitrogen and phosphorus removal. Two different treatment schemes have been proposed in order to optimize the plant performance during both seasonal operations. During low-load season, the plant will be operated under extended aeration conditions, so further sludge stabilization will not be needed. During high-load season, the plant will be operated un…
New processes of the circular economy in water and wastewater treatment : Waterpro project publication
2021
This report presents results of research done in the WaterPro project New processes of the circular economy in water and wastewater treatment. In this project, water treatment solutions based on material streams produced as sidestreams or wastestreams of industrial processes or mining were researched and developed. These materials were modified for use as adsorbents or precipitation chemicals for water treatment solutions aiming to remove nutrients or metals. Materials such as paper mill sludge, slag, fly ash, jarosite, analcime, and brucite were used. Adsorption, chemical precipitation, and electrochemical precipitation were applied as water purification methods. Experiments were performed…
Methylophilaceae and Hyphomicrobium as target taxonomic groups in monitoring the function of methanol-fed denitrification biofilters in municipal was…
2017
Abstract Molecular monitoring of bacterial communities can explain and predict the stability of bioprocesses in varying physicochemical conditions. To study methanol-fed denitrification biofilters of municipal wastewater treatment plants, bacterial communities of two full-scale biofilters were compared through fingerprinting and sequencing of the 16S rRNA genes. Additionally, 16S rRNA gene fingerprinting was used for 10-week temporal monitoring of the bacterial community in one of the biofilters. Combining the data with previous study results, the family Methylophilaceae and genus Hyphomicrobium were determined as suitable target groups for monitoring. An increase in the relative abundance …