Mining disposal erosion evaluation: A case study

Mining disposal (dumping overburden) area is the primary consideration in the reclamation process in mining activities, especially in mining activity. The current study aims to determine the rate of erosion and the level of erosion hazard at mine disposal using water flow distribution. This research was conducted in a coal mine in Kalimantan. Based on the structure of the runoff flow distribution model, this study divides disposal into three land units. The universal soil loss equation in three land units was obtained for erosion values. The value for each land unit is 76 tons/ha/year, 134 tons/ha/year, and 50 tons/ha/year. These three land units are under the level of moderate and light danger of erosion. Afterward, three recommendations were made to the three land units. The first recommendation is the condition of land cover does not change, and conservation changes; the second recommendation is with changes in land cover, but conservation does not change; and the third recommendation is with conditions of land cover and conservation change. The second recommendation shows the best results compared to the other recommendations.

A techno-economic analysis of membrane-based advanced treatment processes for the reuse of municipal wastewater

The objective of this paper is to compare, under Dutch market conditions, the energy consumption and net costs of membrane-based advanced treatment processes for three water reuse types (i.e. potable, industrial, agricultural reuse). The water source is municipal wastewater treatment plant effluent. Results indicate that the application of reverse osmosis is needed to reclaim high quality water for industrial and potable reuse but not for irrigation water which offers significant energy savings but may not lead automatically to lower net costs. While a reclamation process for industrial reuse is economically most promising, irrigation water reclamation processes are not cost effective due to low water prices. Moreover, process operational expenditures may exceed capital expenditures which is important for tender procedures. A significant cost factor is waste management that may exceed energy costs. Water recovery rates could be significantly enhanced through the integration of a softener/biostabilizer unit prior to reverse osmosis. Moreover, the energy consumption of wastewater reclamation processes could be supplied on-site with solar energy. The possibility of designing a ‘fit for multi-purpose’ reclamation process is discussed briefly. This comparative analysis allows for better informed decision making about which reuse type is preferably targeted in a municipal wastewater reuse project from a process design perspective.

Sludge amendment accelerating reclamation process of reconstructed mining substrates

We constructed a mining soil restoration system combining plant, complex substrate and microbe. Sludge was added to reconstructed mine substrates (RMS) to accelerate the reclamation process. The effect of sludge on plant growth, microbial activity, soil aggregate stability, and aggregation-associated soil characteristics was monitored during 10 years of reclamation. Results show that the height and total biomass of ryegrass increases with reclamation time. Sludge amendment increases the aggregate binding agent content and soil aggregate stability. Soil organic carbon (SOC) and light-fraction SOC (LFOC) in the RMS increase by 151% and 247% compared with those of the control, respectively. A similar trend was observed for the glomalin-related soil protein (GRSP). Stable soil aggregate indexes increase until the seventh year. In short, the variables of RMS determined after 3–7 years insignificantly differ from those of the untreated sample in the tenth-year. Furthermore, significant positive correlations between the GRSP and SOC and GRSP and soil structure-related variables were observed in RMS. Biological stimulation of the SOC and GRSP accelerates the recovery of the soil structure and ecosystem function. Consequently, the plant–complex substrate–microbe ecological restoration system can be used as an effective tool in early mining soil reclamation.