Efficient Management of Sewage Sludge from Urban Wastewaters with the Addition of Inorganic Waste: Focus on Rheological Properties

Abstract

Sewage sludge (SS) from urban wastewater treatment is still an environmental, economic, and social problem. Current SS management is not consensual, and more alternatives are required to recover some valuable compounds, such as nutrients and organic matter. This study investigates the use of green liquor dregs from the pulp and paper industry—GLDs—as an adjuvant of drying, to develop a product for agronomic applications, focusing on the rheological behavior. The rheological properties were assessed for anaerobically digested sludge (ADS). The limit viscosity of raw ADS was about 0.005 Pa·s in the case of 5% TSs (total solids) increasing to 0.51 Pa·s for 20% TSs. From the oscillatory tests, the ideal viscous flow below 10% TSs was observed, whereas a viscoelastic–solid behavior was detected for a higher concentration of TSs. The addition of GLDs to the ADS reduced the consistency index, reducing the shear resistance of the material. Rheological assays showed that GLDs may facilitate sludge handling (e.g., extrusion) from the dewatering unit to the dryer. Overall, the addition of GLDs to ADS showed to be a viable option for drying and subsequent soil application. Reusing both residues promote the transition from a linear to a circular economy in the wastewater treatment sector.

Numerical examination of concentration-dependent wastewater sludge ejected into a drinking water source

“…In this section, numerical results of the dimensionless problems (6) subject to the initial and boundary conditions (7) are presented graphically and in tabular form to describe the effects of various flow parameters on the concentration and flow fields. The numerical results are computed using the quasi-linearized approach based on the bivariate Lagrange polynomials as the trial function and validated with the spectral Chebyshev collocation (11) u(y, t) ≈ U(y, t)…”

“…obtained in [5][6][7][8][9] will break down since the shear stress-strain relation cannot be linear in the non-Newtonian fluid. As a result of this behavior, Santos et al 11 presented a power law rheological model to model sludge behavior from a water treatment plant. Csizmadia and Till 12 , in their study of a comparative analysis of the power law by Bingham and Hersschel-Bulkley, presented non-Newtonian models for activated sludge.…”

“…Motivated by the studies on the non-Newtonian flow documented in [11][12][13][14] , reaction kinetics, and the channel porosity effect 10 , the focus here is to investigate the combined impacts on the work done in 5 . The outcome is expected to be useful in treating wastewater sludge from most treatment plants and other related industrial and manufacturing processes where sludge is constantly ejected into drinking water sources.…”

Research on the Synthesis of Zinc–Ammonium Phosphate Using Galvanic Waste Sludge as a Source of Zinc

“…Waste sludge from industry or urban wastewater treatment plants is a source of revalorization of metals and other useful substances [13][14][15][16][17][18][19][20][21]. Galvanic sludges, generated as a byproduct of electroplating processes, contain valuable metals such as zinc, copper, nickel and chromium.…”

Metal Cation and Surfactant-Assisted Flocculation for Enhanced Dewatering of Anaerobically Digested Sludge

“…The three most common types of sludge conditioning techniques used are inorganic chemical conditioners, organic polymers and thermal conditioning. Metal conditioning agents like FeCl 3 , CaCl 2 , CaCO 3 , CaSO 4 and AlSO 4 can be used for sludge conditoning alone or in combination with other polymers or sufractants [11][12][13]. Conditioning of sludge with aluminum sulphate, ferric chloride, calcium sulphate (gypsum), calcium carbonate (lime) and other divalent metals as coagulation and flocculation agents has resulted in significant outcomes.…”