Mine Water Treatment with a Pilot Scale RAPS-System
In 1985, economic reasons caused the closure of the fluorspar mine “Hohe Warte” near Gernrode in the German Harz Mountains. Though remediation works were conducted in the preceding years, mine water is currently flowing out freely of the dewatering adit and is impacting the environment and the receiving brook. The mine water is characterised by low pH-values, high conductivities and contains considerable amounts of iron, manganese, and arsenic. Annually, the mine discharges 0.7 Mio m of mine water with 7.8 tons of iron, 3.8 tons of manganese and 13 kg of arsenic. Therefore, the discharging mine water has a great potential to affect the quality of the receiving streams and resulted in a decrease of biological diversity. Based on hydrogeological and hydrochemical investigations, a passive treatment system would be able to treat the mine water. In February 2003 a pilot system was installed near the dewatering adit consisting of a settlement pond, a RAPS system and a constructed wetland. It could be shown that this passive system was able to treat an aliquot of the mine water down to ecologically acceptable standards.
PASSIVE TREATMENT OF COAL MINE DRAINAGE 1
Passive treatment systems utilize chemical and biological processes to neutralize acidity and decrease concentrations of metals. These systems have been successfully applied at numerous coal mine discharges over the past 20 years. The three most commonly applied passive unit operations are aerobic ponds/wetlands, anoxic limestone drains (ALDs), and reducing and alkalinity producing systems (RAPS). The selection of the most effective unit operation, or combination of unit operations, is based on water quality. The unit operations are sized based on flow or contaminant loads. Net alkaline water is treated with ponds and aerobic wetlands that promote iron oxidation, precipitation, and settling. Empirical data have shown that 10 - 20 grams of iron is typically removed per square meter of surface area of the pond or wetland. Net acidic water with low ferric iron and aluminum levels can be treated with ALDs, which are used to add bicarbonate alkalinity (typically 100 - 300 mg/L of alkalinity as CaCO3). To attain near maximum levels of alkalinity, ALDs are sized to maintain a 12 -15 hour detention time. Net acidic water containing ferric iron or aluminum is treated using RAPS, which add bicarbonate alkalinity via sulfate reduction and limestone dissolution. The amount of alkalinity generated is dependant on influent water quality, but empirically has been found to range from 15 - 60 grams of alkalinity (as CaCO3) per square meter of pond surface. Many of these systems are constructed to facilitate flushing of retained metals, however, the ability of these systems to maintain adequate permeability has not been determined.
Natural history and long‐term evolution in families with autosomal dominant cortical tremor, myoclonus, and epilepsy
Purpose:  To investigate for the first time the natural history and long‐term evolution of “familial cortical tremor, myoclonus, and epilepsy.”