Search results for "waste disposal"
showing 10 items of 246 documents
Development of a process for the treatment of synthetic wastewater without energy inputs using the salinity gradient of wastewaters and a reverse ele…
2019
Abstract Electrochemical processes are considered very effective methods for the treatment of wastewater contaminated by organics resistant to conventional biological processes and various inorganic pollutants. Large sites that treat wastewaters usually deal with a large number of waters often characterized by different salinity contents, that could be potentially used to provide the energy necessary for the electrochemical remediation. Hence, in this work a reverse electrodialysis (RED) process for the treatment of synthetic wastewaters contaminated by organics, without energy inputs, using the salinity gradient of different wastewaters, was studied, for the first time. It was found that t…
Simultaneous nitritation-denitritation for the treatment of high-strength nitrogen in hypersaline wastewater by aerobic granular sludge
2015
Abstract Fish processing industries produce wastewater containing high amounts of salt, organic matter and nitrogen. Biological treatment of such wastewaters could be problematic due to inhibitory effects exerted by high salinity levels. In detail, high salt concentrations lead to the accumulation of nitrite due to the inhibition of nitrite-oxidizing bacteria. The feasibility of performing simultaneous nitritation and denitritation in the treatment of fish canning wastewater by aerobic granular sludge was evaluated, and simultaneous nitritation–denitritation was successfully sustained at salinities up to 50 gNaCl L −1 , with a yield of over 90%. The total nitrogen concentration in the efflu…
Short-term effect of ammonia concentration and salinity on activity of ammonia oxidizing bacteria.
2010
A continuously aerated SHARON (single reactor high activity ammonia removal over nitrite) system has been operated to achieve partial nitritation. Two sets of batch experiments were carried out to study the effect of ammonia concentration and salinity on the activity of ammonia-oxidizing bacteria (AOB). Activity of AOB raised as free ammonia concentration was increased reaching its maximum value at 4.5 mg NH 3 -N l −1 . The half saturation constant for free ammonia was determined (K NH 3 = 0.32 mg NH 3 -N l −1 ). Activity decreased at TAN (total ammonium–nitrogen) concentration over 2,000 mg NH 4 -N l −1 . No free ammonia inhibition was detected. The effect of salinity was studied by adding…
Business Models and Economic Approaches for Recovering Energy from Wastewater and Fecal Sludge
2015
Universal access to water, sanitation and energy services are key challenges in low income countries. The conventional model of providing water, sanitation and waste disposal as a social service is no longer viable because national authorities lack financial and human resources for operation and maintenance and for addressing the sanitation needs locally. Human excreta and wastewater represent resources that can be used to generate new income and support livelihoods through use as a source of energy. The reduction, removal and reuse of wastes must become financially feasible and economically profitable and yield high returns. This requires innovative and sustainable business models and fina…
Determination of the porosity, permeability and diffusivity of rock in the excavation-disturbed zone around full-scale deposition holes using the -PM…
1998
Abstract Three experimental holes the size of deposition holes in a KBS-3 type repository (depth 7.5 m and diameter 1.5 m) were bored in hard granitic rock in the Research Tunnel at Olkiluoto to study, among other things, the properties of the rock in the excavation-disturbed zone. In the analysis described in this report, the porosities, effective diffusivities and permeabilities of disturbed and intact rock were determined by using two novel methods: the 14 C -polymethylmethacrylate method and the He-gas method. In addition, the structure of the rock in the excavation-disturbed zone was assessed using both scanning electron and optical microscopy.
Assessing the sustainability of small wastewater treatment systems: A composite indicator approach
2014
The assessment of the sustainability of wastewater treatment (WWT) systems has gained interest in recent years. However, most previous studies have focused on environmental and/or economic dimensions ignoring social aspects. Moreover, they tend to be based on sets of indicators rather than providing a holistic assessment. To overcome this limitation, this paper proposes an innovative methodology to assess the sustainability of WWT systems based on the development of a composite indicator embracing economic, environmental and social issues. Subsequently, the global sustainability of seven WWT technologies for secondary treatment in small communities is compared. The joint application of the …
Assessment of wastewater treatment plant design for small communities: Environmental and economic aspects
2012
The preliminary design and economic assessment of small wastewater treatment plants (less than 2000 population equivalent) are issues of particular interest since wastewaters from most of these agglomerations are not covered yet. This work aims to assess nine different technologies set-up for the secondary treatment in such type of facilities embracing both economic and environmental parameters. The main novelty of this work is the combination of an innovative environmental decision support system (EDSS) with a pioneer approach based on the inclusion of the environmental benefits derived from wastewater treatment. The integration of methodologies based on cost-benefit analysis tools with th…
Assessment of wastewater treatment alternatives for small communities: An analytic network process approach
2015
The selection of the most appropriate wastewater treatment (WWT) technology is a complex problem since many alternatives are available and many criteria are involved in the decision-making process. To deal with this challenge, the analytic network process (ANP) is applied for the first time to rank a set of seven WWT technology set-ups for secondary treatment in small communities. A major advantage of ANP is that it incorporates interdependent relationships between elements. Results illustrated that extensive technologies, constructed wetlands and pond systems are the most preferred alternatives by WWT experts. The sensitivity analysis performed verified that the ranking of WWT alternatives…
The use of constructed wetlands for the treatment and reuse of urban wastewater for the irrigation of two warm-season turfgrass species under Mediter…
2017
Constructed wetlands (CWs) represent low-cost technology for the treatment and reuse of wastewater in urban areas. This study aimed to evaluate the pollutant removal efficiency of a CW system and to assess the effects of irrigation using treated urban wastewater on soil and on two warm-season turf species. The research was carried out in Sicily (Italy) on a pilot-scale horizontal subsurface flow system which was fed with treated urban wastewater following secondary treatment from an activated-sludge wastewater treatment plant. The pilot system was located in an open urban park and comprised two separate parallel planted units. Experimental fields of Cynodon dactylon (L.) Pers. and Paspalum …
Stable isotope evidence for the environmental impact of a land-based fish farm in the western Mediterranean
2004
Isotopic examination (delta(13)C and delta(15)N) of organic matter sources and consumers was used to assess the impact and trace the dispersal of wastewater from a land-based fish farm in western Mediterranean. The results provide evidence of the non-negligible effect of aquaculture facilities on the natural stable isotopic composition of organisms. Aquaculture waste entered the food web, altering the natural isotopic composition of organic matter sources at the base and the upper trophic levels. Nitrogen-rich fish waste mainly affected delta(15)N values, while delta(13)C showed less alteration. Waste seemed to disperse widely enough to affect the isotopic composition at the study site abou…