67 research outputs found
Comparative Life Cycle Assessment of Sewage Sludge (Biosolid) Management Options
Sludge formation during wastewater treatment is inevitable even with proper management and treatment. However, the proper treatment and disposal of sludge are still difficult in terms of cost of treatment, the presence of new pollutants, health problems, and public acceptance. Conventional disposal methods (e.g., storage, incineration) have raised concerns about legislative constraints and community perception that encourage the assessment of substitute sludge management options. Sludge management requires a systematic solution that combines environmental effectiveness, social acceptability, and economic affordability. Life cycle assessment is one of the most important tools to identify and compare the environmental impact of sludge treatment technologies to ensure sustainable sludge management. Increased production of sludge (biosolids) increases worldwide due to population growth, urban planning, and industrial developments. The sludge needs to be properly treated and environmentally managed to reduce the negative effects of its application or disposal. This chapter deals with the application of biosolids or sewage sludge, together with possible resources for sustainable development. In this section, the life cycle assessments of sludge treatment methods were also investigated and found that sludge treatment techniques lead to major environmental impact categories such as global warming potential, human toxicity, acidification potential, and resource consumption
Two-sided eigenvalue bounds for the spherically symmetric states of the Schrödinger equation
AbstractThe eigenvalues of the radial Schrödinger equation are calculated very accurately by obtaining exact upper and lower bounds. By truncating the usual unbounded domain [0, ∞) of the system to a finite interval of the form [0,l], two auxiliary eigenvalue problems are defined. It is then proved that the eigenvalues of the resulting confined systems provide upper and lower bounds converging monotonically to the true eigenvalues required. Moreover, each auxiliary eigenvalue problem gives rise to an orthonormal set involving Bessel functions. The matrix representation of the Hamiltonian is, therefore, derived by expanding the wave function into a Fourier-Bessel series. Numerical results for single- and double-well polynomial oscillators as well as Gaussian type non-polynomial potentials illustrate that the eigenvalues can be calculated to an arbitrary accuracy, whenever the boundary parameter l is in the neighborhood of some critical value, denoted by lcr
Sustainability Assessment of Wastewater Treatment Plants
It is thought that this chapter will make a significant contribution to the literature or at least will fill the space on the wastewater treatment plant’s effect on climate change. It demonstrates the potential climate change impact of a sequential batch reactor (SBR) and constructed wetland on treating domestic wastewater by giving methods for calculation of their greenhouse gas emissions in terms of N2O and CH4. Are wastewater treatment plants sustainable? What aspects determine sustainability? Do tertiary wastewater treatment plants and constructed wetlands (CWs) have less global warming potential (CO2 emissions) and less energy use than conventional treatment? In accordance with the literature, greenhouse gas calculations of this study showed that CWs and SBR WWTPs do not contribute to global warming negatively
Accurate energy spectrum for double-well potential: periodic basis
We present a variational study of employing the trigonometric basis functions
satisfying periodic boundary condition for the accurate calculation of
eigenvalues and eigenfunctions of quartic double-well oscillators. Contrary to
usual Dirichlet boundary condition, imposing periodic boundary condition on the
basis functions results in the existence of an inflection point with vanishing
curvature in the graph of the energy versus the domain of the variable. We show
that this boundary condition results in a higher accuracy in comparison to
Dirichlet boundary condition. This is due to the fact that the periodic basis
functions are not necessarily forced to vanish at the boundaries and can
properly fit themselves to the exact solutions.Comment: 15 pages, 5 figures, to appear in Molecular Physic
Green Stormwater Infrastructure in the Context of the European Green Deal Policy
It is thought that this section will make an important contribution to the literature and at least reflect the strong link between green stormwater infrastructure and the European Green Deal Policy to the readers. The European Green Deal has targets covering many different sectors, including construction, biodiversity, energy, transportation, and food, which include the enactment of new laws on green rainwater infrastructure. Green stormwater infrastructure not only controls stormwater volume and timing but also supports the benefits ecosystems bring to us. Stormwater is defined as rainwater or melted snow runoff from streets, lawns, and other areas. When rainstorm water is absorbed into the soil, it is filtered and eventually replenishes aquifers or flows into streams and rivers. Runoff carries sediments, nutrients, or other pollutants into water sources that degrade water quality, threaten drinking water supplies, and complicate water treatment processes. When drought concentrates pollutants, it can further limit dilution, making worse conditions. In order to prevent the problems caused by inefficient rainwater management systems, green infrastructure applications that mimic natural habitats, absorb excess water, and help protect water while preserving water quality have gained importance in recent years
Variational collocation for systems of coupled anharmonic oscillators
We have applied a collocation approach to obtain the numerical solution to
the stationary Schr\"odinger equation for systems of coupled oscillators. The
dependence of the discretized Hamiltonian on scale and angle parameters is
exploited to obtain optimal convergence to the exact results. A careful
comparison with results taken from the literature is performed, showing the
advantages of the present approach.Comment: 14 pages, 10 table
Approximate analytic solutions of the diatomic molecules in the Schrodinger equation with hyperbolical potentials
The Schrodinger equation for the rotational-vibrational (ro-vibrational)
motion of a diatomic molecule with empirical potential functions is solved
approximately by means of the Nikiforov-Uvarov method. The approximate
ro-vibratinal energy spectra and the corresponding normalized total
wavefunctions are calculated in closed form and expressed in terms of the
hypergeometric functions or Jacobi polynomials P_{n}^{(\mu,\nu)}(x), where
\mu>-1, \nu>-1 and x included in [-1,+1]. The s-waves analytic solution is
obtained. The numerical energy eigenvalues for selected H_{2} and Ar_{2}
molecules are also calculated and compared with the previous models and
experiments.Comment: 18 page
Assessing the transition of municipal solid waste management using combined material flow analysis and life cycle assessment
Faced with the challenges to deal with increasingly growing and ever diversified municipal solid waste (MSW), a series of waste directives have been published by European Commission to divert MSW from landfills to more sustainable management options. The presented study assessed the transition of MSW man-agement in Nottingham, UK, since the enforcement of the EU Landfill Directive using a tool of combined materials flow analysis (MFA) and life cycle assess-ment (LCA). The results show that the MSW management system in Nottingham changed from a relatively simple landfill & energy from waste (EfW) mode to a complex, multi-technology mode. Improvements in waste reduction, material re-cycling, energy recovery, and landfill prevention have been made. As a positive result, the global warming potential (GWP) of the MSW management system re-duced from 1,076.0 kg CO2–eq./t of MSW in 2001/02 to 211.3 kg CO2–eq./t of MSW in 2016/17. Based on the results of MFA and LCA, recommendations on separating food waste and textile at source and updating treatment technologies are made for future improvement
Novel Bound States Treatment of the Two Dimensional Schrodinger Equation with Pseudocentral Plus Multiparameter Noncentral Potential
By converting the rectangular basis potential V(x,y) into the form as
V(r)+V(r, phi) described by the pseudo central plus noncentral potential,
particular solutions of the two dimensional Schrodinger equation in plane-polar
coordinates have been carried out through the analytic approaching technique of
the Nikiforov and Uvarov (NUT). Both the exact bound state energy spectra and
the corresponding bound state wavefunctions of the complete system are
determined explicitly and in closed forms. Our presented results are identical
to those of the previous works and they may also be useful for investigation
and analysis of structural characteristics in a variety of quantum systemsComment: Published, 16 page
- …