Vane shear strength of dewatered sludge from Hong Kong

2001 ◽  
Vol 44 (2-3) ◽  
pp. 389-397 ◽  
Author(s):  
A. Koenig ◽  
Q. H. Bari

The vane shear strength and total solids content of dewatered sludge from Hong Kong were determined in order to evaluate their geotechnical suitability for disposal in landfills. The results obtained indicate that (i) the total solids and vane shear strength of dewatered sludge from different treatment plants varied considerably depending on the type of sludge and dewatering method; and, (ii) percent total solids alone is not sufficient to guarantee geotechnical stability in terms of vane shear strength. The critical state model for soils provided a good fit for the characteristic relationship between vane shear strength and total solids, which can be used to estimate vane shear strength from total solids only. No relationship between volatile solids and vane shear strength was found. The results of the laboratory vane shear test correlated well with those obtained by a pocket shearmeter indicating the usefulness of this method for rapid determination of vane shear strength on site. Some factors that influence vane shear strength were briefly evaluated. Implications of the results for sludge management with special emphasis on dewatering and landfilling were discussed.

2008 ◽  
Vol 57 (9) ◽  
pp. 918-923 ◽  
Author(s):  
Zeena P. Hamza ◽  
K. F. Anna Dilfi ◽  
M. N. Muralidharan ◽  
Thomas Kurian

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 4763-4780
Author(s):  
Saraí Camarena-Martínez ◽  
Juan H. Martínez-Martínez ◽  
Adriana Saldaña-Robles ◽  
Hector G. Nuñez-Palenius ◽  
Rogelio Costilla-Salazar ◽  
...  

In Mexico, protected agriculture generates large amounts of tomato and pepper plants residues (TPW and PPW, respectively). Given the limited information on methane production from anaerobic digestion of these wastes, this study aimed to determine the effects of the substrate/inoculum (S/I) ratio, temperature, and total solids content on methane production and volatile solids (VS) removal by two subsequent batch experiments (Experiments A and B). Experiment A was performed to evaluate the substrate/inoculum ratios of 0.5, 1.0, and 2.0 at room temperature (22 ± 4.5 °C). Based on the best methane yield from experiment A, a new experiment was established (Experiment B) using only tomato wastes, where temperature was kept at 29 °C and 39 °C. The total solids content was analyzed depending on the S/I ratio used. For both substrates, an S/I ratio of 0.5 was the most appropriate for methane production. The temperature had a positive effect on volatile solids removal and methane yield. In contrast, the total solids content (% TS) only had a positive effect on methane production. To the authors’ knowledge, this is the first study evaluating the effect of the S/I ratio on methane production from tomato and pepper plant wastes.


2019 ◽  
Vol 37 (5) ◽  
pp. 542-550 ◽  
Author(s):  
Irena Wojnowska-Baryła ◽  
Dorota Kulikowska ◽  
Katarzyna Bernat ◽  
Sławomir Kasiński ◽  
Magdalena Zaborowska ◽  
...  

Autoclaving of unsorted municipal solid waste is one of the solutions in waste management that maximises the amount of waste for recycling. After autoclaving, however, a large part of the waste is composed of unstabilised biodegradable fractions (organic remaining fraction, ORF), which may comprise up to 30% of autoclaved waste and cannot be landfilled without further stabilisation. Thus, the aim of this study was to investigate the effectiveness of aerobic stabilisation in a passively aerated reactor of organic remaining fraction after full-scale autoclaving of unsorted municipal solid waste. The organic remaining fraction had a volatile solids content of ca. 70%, a 4-day respiration activity test (AT4) of ca. 26 g O2 kg–1 total solids and a 21-day gas formation test (GP21) of ca. 235 dm3 kg–1 total solids. Stabilisation was conducted in a 550 L reactor with passive aeration (Stage I) and a periodically turned windrow (Stage II). The feedstocks consisted entirely of organic remaining fraction, or of organic remaining fraction with 10% inoculum (ORF + I). Inoculum constituted product of stabilisation of organic remaining fraction. During stabilisation of organic remaining fraction and ORF + I, thermophilic conditions were achieved, and the decreases of volatile solids, AT4 and GP21 could be described by 1 order kinetic models. The rate constants of volatile solids removal (kVS) were 0.033 and 0.068 d–1 for organic remaining fraction and ORF + I, respectively, and the thermophilic phase was shorter with ORF + I (25 days vs. 45 days). The decrease in GP21 corresponded to volatile solids decrease, but AT4 decreased sharply during the first 10 days of waste stabilisation in the reactor, indicating that the content of highly biodegradable organic matter decreased during this time.


2020 ◽  
Vol 28 (5-6) ◽  
pp. 344-350
Author(s):  
M Gonçalves ◽  
NT Paiva ◽  
JM Ferra ◽  
J Martins ◽  
F Magalhães ◽  
...  

Near infrared (NIR) spectroscopy is a fast and reliable technique for assessing properties of amino resins. One important property that defines the cost and performance of these resins is the solids content (SC). This work studied the prediction of SC of amino resins by combining NIR spectroscopy with partial least squares (PLS) regression. A total of 990 industrial NIR spectra of amino resins were obtained and split randomly by a ratio of 2/3 for calibration and 1/3 for validation. The best model achieved a root mean-square error of prediction (RMSEP) of 0.32% (m/m) and a coefficient of determination of prediction ([Formula: see text]) of 81%. standard normal variate (SNV) was found to be the NIR pre-processing that provided the best results for model construction. Addition of water to two amino resins showed that the NIR model does not respond to the water addition, despite water making great contribution to the SC value. An inference that can be obtained from this is that the NIR model of amino resins uses NIR properties of amino resins that relate to the SC and from there predict the most probable SC, instead of looking at all the components that affect the SC of amino resins.


Sign in / Sign up

Export Citation Format

Share Document