A novel algorithm for vertical soil layering by utilizing the CPT data

Determination of the relevant soil stratigraphy is of the paramount importance for any geotechnical analysis. The cone penetration test (CPT) is the cost-effective, rapid, continuous, and reliable testing method for assessing soil layering and estimating in-situ mechanical properties of soil, and as such is especially useful for subsoil investigations along linear infrastructure networks, such as roads, highways, or railways. The design soil profile can be effectively determined using the CPT-based soil behaviour type (SBT) classification system. However, the soil profile consists of layers of various thickness and some layers can be only a few centimetres thick. Because the cone needs to penetrate to a certain depth to develop the cone resistance and to identify the presence of another layer, thin layers of soil cannot be properly detected. The soil layering algorithm, presented in this paper, merges these thin layers into the adjacent layers and thus overcomes the unreliable determination of the thin layers. The implementation of the proposed algorithm is demonstrated using a CPT carried out on the embankment test-site in north Croatia.

First Report on Cyanotoxin (MC-LR) Removal from Surface Water by Multi-Soil-Layering (MSL) Eco-Technology: Preliminary Results

Cyanobacteria blooms occur frequently in freshwaters around the world. Some can produce and release toxic compounds called cyanotoxins, which represent a danger to both the environment and human health. Microcystin-LR (MC-LR) is the most toxic variant reported all over the world. Conventional water treatment methods are expensive and require specialized personnel and equipment. Recently, a multi-soil-layering (MSL) system, a natural and low-cost technology, has been introduced as an attractive cost-effective, and environmentally friendly technology that is likely to be an alternative to conventional wastewater treatment methods. This study aims to evaluate, for the first time, the efficiency of MSL eco-technology to remove MC-LR on a laboratory scale using local materials. To this end, an MSL pilot plant was designed to treat distilled water contaminated with MC-LR. The pilot was composed of an alternation of permeable layers (pozzolan) and soil mixture layers (local sandy soil, sawdust, charcoal, and metallic iron on a dry weight ratio of 70, 10, 10, and 10%, respectively) arranged in a brick-layer-like pattern. MSL pilot was continuously fed with synthetic water containing distilled water contaminated with increasing concentrations of MC-LR (0.18–10 µg/L) at a hydraulic loading rate (HLR) of 200 L m−2 day−1. The early results showed MC-LR removal of above 99%. Based on these preliminary results, the multi-soil-layering eco-technology could be considered as a promising solution to treat water contaminated by MC-LR in order to produce quality water for irrigation or recreational activities.

Experimental Study on the Treatment of Rural Domestic Wastewater Using the Multi-Soil-Layering System Filled with Sludge-Based Biochar

This paper aims to improve the treatment effect of the multi-soil-layering system (MSL) on rural domestic wastewater. For this, sludge-based biochar materials were selected in the experiments to study its impacts on the treatment of rural domestic wastewater using the MSL. The comparative experiments were conducted for the three MSL systems filled with different materials: the sludge-based biochar (a), wood chips (b), and charcoal (c). The results showed that when the sludge-based biochar material was used as a filler, the removal effect of COD, NH4+-N, TN, TP is better than that of wood chips and charcoal, and the removal rates were 80%, 90%, 65% and 92%, respectively, meeting the Grade A standard specified in the Hebei Province Rural Domestic wastewater Discharge Standard (DB13/2171-2015); hydraulic loading rates (HLRs) have a great impact on the removal of pollutants, and the pollutant indicators in the system (a)re affected by the HLRs in different degrees, i.e., NH4+-N>TP>COD>TN from high to low; considering the treatment efficiency and pollutant removal effect, the HLRs should be selected between 800L/(m2·d) and 1200L/(m2·d). It’s concluded finally that the sludge-based biochar material can strengthen the removal effect of the MSL system. This study is of theoretical value for the further research on MSL system and resource utilization of the sludge.