Cement bentonite (CB) barriers are selfsupporting, low permeability, structures used to retard groundwater flow and as such strength and hydraulic conductivity parameters are often stipulated when developing the mixtures. This paper reports an investigation into the deformation and compression behaviour of a CB containing ground granulated blastfurnace slag using the unconfined compressive strength apparatus, triaxial (undrained, unconsolidated) and oedometer. Samples were also exposed to drying and rewetting to investigate possible response to changes in environmental conditions. Cracking was observed prior to peak stress suggesting that the hydraulic conductivity of a barrier may be adversely affected before the shear strength is reached in undrained conditions. The compression response of CB indicates the presence of a threshold stress; once exceeded the magnitude of settlements are significantly greater than those encountered below this threshold. If a barrier experiences localised changes in loading conditions then there is the potential for damage from induced differential settlements; thus it is recommended that the threshold stress should also be considered at the design stage in addition to strength and hydraulic conductivity requirements. The response of the material exposed to drying-rewetting was unexpected and requires further investigation to determine how a barrier will respond to changing environmental conditions.

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Sedimentary soils are formed from deposits resulting from weathering of rocks through natural processes. One way to increase the bearing capacity of sedimentary soil is by stabilizing it. The purpose of this study was to determine the effect of variations in the mixture of Bacillus Subtilis bacteria on the characteristics of sedimentary soils and to determine the effect of the curing period on the shear strength of the sediment stabilized by Bacillus subtilis bacteria. Based on the results of physical properties testing, the original soil was classified as ML, which is silt with low plasticity based on the USCS classification system, and classified as soil group A-4, namely silty soil according to the AASHTO classification system. The addition of Bacillus Subtilis bacteria mixed with urea and CaCl2 was proven to increase the value of shear stress, cohesion, and shear angle of the soil. The addition of Bacillus Subtilis with a mixture of urea and CaCl2 to the sedimentary soil accompanied by a curing period was shown to increase the shear stress at the percentage of adding stabilizing agent 8% from 1.25 kg/cm2, 1.45 kg/cm2, and 1.77 kg/cm2 at the beginning to 1.73 kg/cm2, 2.09 kg/cm2, and 2.39 kg/cm2 at 28 days of curing, with an average increase of 35 percent. The cohesion value continued to increase from the initial value of 0.72 kg/cm2 to 1.57 kg/cm2 at 28 days of curing, resulting in an increase in cohesion value of 118 percent. For the value of the shear angle in the soil, there was an increase from the original soil shear angle value of 22° to 31° in a mixture of 8% bacteria with a curing period of 28 days so that there was an increase in the value of the shear angle by 40 percent.

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The rapid population growth in many countries will ultimately impact the provision of essential services and engender many challenges, such as inadequate sanitation. Indonesia has an extensive coastline and densely populated coastal areas that have grown sporadically, creating slums. These areas have long been associated with poor greywater management. Greywater is dumped into beaches, roads, and yards without pre-treatment, thus harming the environment and society. This study aims to identify various factors influencing community actions to manage and overcome greywater-related problems in coastal slum areas. Using methods by combining qualitative and quantitative approaches. The influential factors in the physical condition of the built environment, the natural environment, community activities, and government involvement related to greywater were analyzed qualitatively, while the public understanding of greywater management was assessed quantitatively. The results showed that these four factors significantly influenced people's attitudes towards wastewater treatment. The findings show that these four factors affect people's mind-set about handling greywater, which becomes an obstacle to changing their attitudes and views on greywater. The four factors have the same level and cannot be separated in dealing with greywater. Treatment strategies are in accordance with coastal nature, settlements physical conditions and communities are then chosen Treatment Horizontal Flow. Doi: 10.28991/CEJ-2022-08-12-05 Full Text: PDF