Pressuremeter tests in municipal solid waste: measurement of shear stiffness

To assess the long-term integrity, and hence adequate performance, of landfill lining systems the designer must consider interaction between lining components and the waste body. Information on typical ranges of waste mechanical properties is required for use in numerical modelling of this interaction. This paper presents results from a programme of pressuremeter testing in municipal solid waste (MSW) carried out to measure shear stiffness properties. An optimum procedure has been developed using a high-pressure dilatometer in a preformed test pocket. Tests have been conducted in fresh and partially degraded MSW deposits. Values of shear moduli for small to intermediate strains have been obtained from series of unload–reload loops, and these show a strong relationship between shear modulus and depth. Stiffness increases with cavity strain owing to drained cavity expansion. A clear linear relationship has been found between shear stiffness and stress level. Results for fresh MSW from two landfill sites show close agreement. Good agreement has been found between shear stiffness values calculated for small strain in pressuremeter tests and shear stiffness values measured using the continuous surface wave method. They also compare well with the limited amount of information in the literature

Feasibility and performance efficiency of integrated microbial nutrient recovery cell and microalgae-activated sludge process for wastewater treatment

Microbial nutrient recovery cell (MNRC) and microalgae-activated sludge (MAAS) are both the most attractive emerging methods of wastewater treatment technology due to their promising potential to revolutionize wastewater treatment systems. However, despite this giant stride both methods still have some limitations. To address some of these limitations such as energy cost-effectiveness and improved bio-resource recovery, this research integrated both MASS and MNRC for its feasibility studies and performance efficiency. Three sets of reactors including an MNRC-based reactor named microbial nutrient recovery cell (MNRC) reactor; and two MAAS photobioreactors (PBRs) at varying mix ratios of wastewater and pre-cultured microalgae; PBRI (80:20) and PBRII (70:30) were studied. Notably, the pre-cultured microalgae applied in the PBRs were inoculated with nutrients recovered from the MNRC encouragements representing the integrated MNRC-MAAS system. The outcome of microalgae preculture using recovered nutrients presents a chlorophyll concentration of 5.8 mg/L and dissolved (DO) saturation concentration of 14.33 mg/L with a person coefficient of correlation (r) of 0.99, The performance efficiency of the integrated MNRC-MAAS with PBRI(80:20) mix ratio by volume of Wastewater and Microalgae has a higher cumulative percentage removal efficiency of BOD5, NH4, NO3, and PO4 of 98.07 %, 92.05 % 88.07 %, and 90.96 % after 18 days hydraulic retention reactors compared to PBR(70:30) ratio. Consequently, The integrated MNRC-MAAS process has become an attractive alternative wastewater bioremediation with efficient resource recovery