Showing papers on "Wastewater published in 2007"
TL;DR: The processes that affect removal and retention of nitrogen during wastewater treatment in constructed wetlands (CWs) are manifold and include NH(3) volatilization, nitrification, denitrification, nitrogen fixation, plant and microbial uptake, mineralization, mineralification, nitrate reduction to ammonium, anaerobic ammonia oxidation, fragmentation, sorption, desorption, burial, and leaching.
2,313 citations
TL;DR: This study illustrates the usefulness of multivariate statistical techniques for analysis and interpretation of complex data sets, and in water quality assessment, identification of pollution sources/factors and understanding temporal/spatial variations in waterquality for effective river water quality management.
Abstract: Multivariate statistical techniques, such as cluster analysis (CA), principal component analysis (PCA), factor analysis (FA) and discriminant analysis (DA), were applied for the evaluation of temporal/spatial variations and the interpretation of a large complex water quality data set of the Fuji river basin, generated during 8 years (1995–2002) monitoring of 12 parameters at 13 different sites (14 976 observations). Hierarchical cluster analysis grouped 13 sampling sites into three clusters, i.e., relatively less polluted (LP), medium polluted (MP) and highly polluted (HP) sites, based on the similarity of water quality characteristics. Factor analysis/principal component analysis, applied to the data sets of the three different groups obtained from cluster analysis, resulted in five, five and three latent factors explaining 73.18, 77.61 and 65.39% of the total variance in water quality data sets of LP, MP and HP areas, respectively. The varifactors obtained from factor analysis indicate that the parameters responsible for water quality variations are mainly related to discharge and temperature (natural), organic pollution (point source: domestic wastewater) in relatively less polluted areas; organic pollution (point source: domestic wastewater) and nutrients (non-point sources: agriculture and orchard plantations) in medium polluted areas; and organic pollution and nutrients (point sources: domestic wastewater, wastewater treatment plants and industries) in highly polluted areas in the basin. Discriminant analysis gave the best results for both spatial and temporal analysis. It provided an important data reduction as it uses only six parameters (discharge, temperature, dissolved oxygen, biochemical oxygen demand, electrical conductivity and nitrate nitrogen), affording more than 85% correct assignations in temporal analysis, and seven parameters (discharge, temperature, biochemical oxygen demand, pH, electrical conductivity, nitrate nitrogen and ammonical nitrogen), affording more than 81% correct assignations in spatial analysis, of three different sampling sites of the basin. Therefore, DA allowed a reduction in the dimensionality of the large data set, delineating a few indicator parameters responsible for large variations in water quality. Thus, this study illustrates the usefulness of multivariate statistical techniques for analysis and interpretation of complex data sets, and in water quality assessment, identification of pollution sources/factors and understanding temporal/spatial variations in water quality for effective river water quality management.
1,481 citations
TL;DR: Conventional drinking water treatment methods were relatively inefficient for contaminant removal, while efficient removal was achieved by granular activated carbon (GAC).In wastewater treatment processes, membrane bioreactors showed limited target compound removal, but were effective at eliminating hormones and some pharmaceuticals.
1,288 citations
TL;DR: In this paper, over 160 publications related to fermentative hydrogen production from wastewater and solid wastes by mixed cultures are compiled and analyzed, including pre-treatment conditions for screening hydrogen-producing bacteria from anaerobic sludge or soil, and the process and performance parameters for (2) single substrates in synthetic wastewaters, (3) actual wastewater, and (4) solid wastes.
Abstract: Over 160 publications related to fermentative hydrogen production from wastewater and solid wastes by mixed cultures are compiled and analyzed. Of the 98 reported cases, 57 used single substrates (mainly carbohydrates), 8 used actual wastewater, and 33 used solid wastes for hydrogen conversion. The key information is compiled in four tables: (1) pretreatment conditions for screening hydrogen-producing bacteria from anaerobic sludge or soil, and the process and performance parameters for (2) single substrates in synthetic wastewaters, (3) actual wastewaters, and (4) solid wastes. Process parameters discussed include pH, temperature, hydraulic retention time, seed sludge, nutrients, inhibitors, reactor design, and the means used for lowering hydrogen partial pressure. Performance parameters discussed include hydrogen yield, maximum volumetric production rate, maximum specific production rate, and conversion efficiency. The outlook for this new technology is discussed at the end.
758 citations
TL;DR: Forward osmosis (FO) is a membrane treatment process that was investigated at bench scale to determine its feasibility to concentrate centrate under both batch and continuous operating conditions, and results demonstrated that high water flux and high nutrient rejection could be achieved.
559 citations
TL;DR: Based on these four full-scale WWTPs evaluated, the apparent removal of organic micropollutants in wastewater is dependent on a combination of biological and physico-chemical treatment processes and operating conditions of the treatment system.
495 citations
TL;DR: A review presents an account of the problem and the description of colour causing components in distillery wastewater and a detailed review of existing biological approaches.
493 citations
TL;DR: No differences in PPCP pollution of the groundwater were found due to irrigation of STP effluent with and without addition of digested sludge, because many polar compounds do not sorb to sludge and lipophilic compounds are not mobile in the soil-aquifer.
419 citations
TL;DR: In this article, sites irrigated with wastewater for 10, 5, and 2 years and sites not irrigated were sampled for soil and plant chemical analysis to evaluate its long term effect.
408 citations
TL;DR: In this paper, the authors reviewed the current status of wastewater irrigation by providing an overview of the extent of the practice throughout the world and synthesizing the current understanding of factors influencing sustainable wastewater irrigation.
Abstract: As demand for fresh water intensifies, wastewater is frequently being seen as a valuable resource. Furthermore, wise reuse of wastewater alleviates concerns attendant with its discharge to the environment. Globally, around 20 million ha of land are irrigated with wastewater, and this is likely to increase markedly during the next few decades as water stress intensifies. In 1995, around 2.3 billion people lived in water-stressed river basins and this could increase to 3.5 billion by 2025. We review the current status of wastewater irrigation by providing an overview of the extent of the practice throughout the world and through synthesizing the current understanding of factors influencing sustainable wastewater irrigation. A theme that emerges is that wastewater irrigation is not only more common in water-stressed regions such as the Near East, but the rationale for the practice also tends to differ between the developing and developed worlds. In developing nations, the prime drivers are livelihood dependence and food security, whereas environmental agendas appear to hold greater sway in the developed world. The following were identified as areas requiring greater understanding for the long-term sustainability of wastewater irrigation: (i) accumulation of bioavailable forms of heavy metals in soils, (ii) environmental fate of organics in wastewater-irrigated soils, (iii) influence of reuse schemes on catchment hydrology, including transport of salt loads, (iv) risk models for helminth infections (pertinent to developing nations), (v) microbiological contamination risks for aquifers and surface waters, (vi) transfer efficiencies of chemical contaminants from soil to plants, (vii) health effects of chronic exposure to chemical contaminants, and (viii) strategies for engaging the public.
363 citations
TL;DR: The occurrence of four anti-inflammatory drugs (diclofenac, ibuprofen, ketoprofen and naproxen), an antiepileptic drug (carbamazepine) and a nervous stimulant (caffeine) in influent and effluent samples from four wastewater treatment plants in Seville was evaluated.
TL;DR: This study verifies the possibility of using inactivated marine green alga U. lactuca and its activated carbon as valuable material for the removal of chromium from aqueous solutions, saline water or wastewater.
TL;DR: In this article, the twin-layer system was used to remove nitrogen and phosphorus from wastewater by two green microalgae (Chlorella vulgaris and Scenedesmus rubescens) using a novel method of algal cell immobilization.
Abstract: Removal of nitrogen and phosphorus from wastewater by two green microalgae (Chlorella vulgaris and Scenedesmus rubescens) was investigated using a novel method of algal cell immobilization, the twin-layer system. In the twin-layer system, microalgae are immobilized by self-adhesion on a wet, microporous, ultrathin substrate (the substrate layer). Subtending the substrate layer, a second layer, consisting of a macroporous fibrous tissue (the source layer), provides the growth medium. Twin-layers effectively separate microalgae from the bulk of their growth medium, yet allow diffusion of nutrients. In the twin-layer system, algae remain 100% immobilized, which compares favourably with gel entrapment methods for cell immobilization. Both microalgae removed nitrate efficiently from municipal wastewater. Using secondary, synthetic wastewater, the two algae also removed phosphate, ammonium and nitrate to less than 10% of their initial concentration within 9 days. It is concluded that immobilization of C. vulgaris and S. rubescens on twin-layers is an effective means to reduce nitrogen and phosphorus levels in wastewater.
TL;DR: Despite the high removal of organic content from the influent wastewater, during 17 months of operation, no significant differences in performance were observed between units.
TL;DR: The results indicate that the electrochemical method is a feasible technique for treatment of textile wastewater and electrochemically treated wastewater can be effectively reused for dyeing application.
TL;DR: In this paper, a plain carbon electrode or graphite-granule packed-bed bioelectrochemically assisted microbial reactors (BEAMRs) capable of continuous or intermittent hydrogen release was examined using domestic wastewater, and the results demonstrate that a wastewater treatment based on a BEAMR was feasible, but improvements are needed in hydrogen recoveries and Coulombic efficiencies to increase the overall hydrogen yield.
TL;DR: Conventional sewage treatment was demonstrated to be much less effective in destroying the antimicrobial agent triclosan than the aqueous-phase removal efficiency of the plant would make believe.
TL;DR: Performance of mediator-less and membrane-less microbial fuel cell (ML-MFC) was evaluated to treat synthetic wastewater and actual sewage, and effect of distance between the electrodes and total surface area of anode on electricity production was evaluated under variable external resistance.
TL;DR: It can be concluded from this study that coagulation/flocculation may be a useful pre-treatment process for beverage industrial wastewater prior to biological treatment.
TL;DR: The obtained results showed that high nitrogen removal efficiency with effluent total nitrogen below 3 mg/L could be achieved and that the nitrifying microbial communities were optimized.
Abstract: Although many studies regarding nitrogen removal via nitrite have been carried out, very limited research has been undertaken on nitrogen removal via nitrite at low temperatures. In this study, to improve the nitrogen removal efficiency from municipal wastewater, a pilot-plant of sequencing batch reactor with a working volume of 54 m3 was used to investigate nitrogen removal via nitrite from municipal wastewater at normal and low water temperature. The obtained results showed that high nitrogen removal efficiency with effluent total nitrogen below 3 mg/L could be achieved. Using real-time control with temperature ranging from 11.9 to 26.5 degrees C under normal dissolved oxygen condition (> or =2.5 mg/L), nitrogen removal via nitrite was successfully and stably achieved for a long period (180 days) with average nitrite accumulation rate above 95%. Fluorescence in situ hybridization was carried out to investigate the quantitative changes of nitrifying microbial community in the activated sludge. Fluorescence in situ hybridization results approved that the nitrifying microbial communities were optimized; ammonia oxidizing bacteria became the dominant nitrifying bacteria and nitrite oxidizing bacteria had been washed out of the activated sludge.
TL;DR: Experimental results have indicated that chemical or electrocoagulation treatment followed by ion-exchange methods were very effective and were capable of elevating quality of the treated wastewater effluent to the reuse standard of the textile industry.
TL;DR: In this article, the effects of thermal treatment on the semi-continuous anaerobic digestion of the main sludge compounds (proteins, carbohydrates and lipids) were studied.
TL;DR: In this article, an updated review on EDCs and their removal by photocatalysis (PC) and ultrasound oxidation (US) from aqueous spiked solutions and wastewater is presented.
TL;DR: Poplar wood sawdust was examined for adsorption as a replacement for current, more expensive methods of removing copper, zinc and cadmium from electroplating wastewater and suggests that the presence of other ions in wastewater hindered Adsorption of cadmiam ions.
TL;DR: In this paper, the authors presented the comparative results with respect to electrode configurations on the economic performance of treatment of textile wastewaters by electrocoagulation (EC) process.
TL;DR: O(3) provided superior disinfection compared to O(3)/H(2)O( 2) while minimizing DBP concentrations, important considerations for water reuse, aquifer storage and recovery, and advanced wastewater treatment applications.
TL;DR: A constructed wetland for the treatment of agricultural wastewater from a 150-cow dairy operation in this watershed was monitored in its eighth operating season to evaluate the proportion of total nitrogen (TN) (approximated by total Kjeldahl nitrogen (TKN) due to low NO 3 − ) and total phosphorus (TP) removal that could be attributed to storage in Typha latifolia L. as mentioned in this paper.
TL;DR: TaqMan(R) real-time quantitative PCR method was effective for the detection of pathogens in wastewater and confirmed that the risk of exposure to pathogens in the wastewater discharge was well within the Environment Canada guidelines.
01 Jan 2007
TL;DR: Waste Related to the Food Industry: A Challenge in Material Loops and to Food Waste Treament: The 14001 Standards as mentioned in this paper, Basic Unit Operations in Wastewater Treatment and Anaerobic Digestion of Organic Residues and Wastes.
Abstract: Waste Related to the Food Industry: A Challenge in Material Loops.- to Food Waste Treament: The 14001 Standards.- Basic Unit Operations in Wastewater Treatment.- Anaerobic Digestion of Organic Residues and Wastes.- Fundamentals and Applications of Anaerobic Digestion For Sustainable Treatment of Food Industry Wastewater.- Fermentation of Distiller's Wash in a Biogas Plant.- Brewery and Winery Wastewater Treatment: Some Focal Points of Design and Operation.- Olive Mill Wastewater Treatment.- Anaerobic Degradation of Animal By-Products.- Utilization of Whey.- Utilization of Plant By-Products for the Recovery of Proteins, Dietary Fibers, Antioxidants, and Colorants.- Utilization of By-Products in the Fish Industry.- Examples of Special Case Studies in Different Branches.- Incineration of Solid Food Waste: A Project About Spent Grain.- Composting of Food and Agricultural Wastes.
TL;DR: In this article, the authors used n-hexane, methanol, acetone, and supercritical CO2 solvents to extract lipids from sewage sludge.
Abstract: Municipal wastewater treatment plants in the USA produce over 6.2 × 106 t of dried sewage sludge every year. This microorganism-rich sludge is often landfilled or used as fertilizer. Recent restrictions on the use of sewage sludge, however, have resulted in increased disposal problems. Extraction of lipids from sludge yields an untapped source of cheap feedstock for biodiesel production. Solvents used for extraction in this study include n-hexane, methanol, acetone, and supercritical CO2. The gravimetric yield of oil was low for nonpolar solvents, but use of polar solvents gave a considerably increased yield; however, the percentage of saponifiable material was less. Extraction of lipids with a mixture of n-hexane, methanol, and acetone gave the largest conversion to biodiesel compared with other solvent systems, 4.41% based on total dry weight of sludge. In situ transesterification of dried sludge resulted in a yield of 6.23%. If a 10% dry weight yield of fatty acid methyl esters is assumed, the amount of biodiesel available for production in the USA is 1.4 × 106 m3/year. Outfitting 50% of municipal wastewater plants for lipid extraction and transesterification could result in enough biodiesel production to replace 0.5% of the national petroleum diesel demand (0.7 × 106 m3).