DAEKYOO HWANG
Engineers in West Chester, PA

5885026, Mar 23, 1999

May 29, 1997

8/865284

Daekyoo Hwang - West Chester PA

LG Engineering Co., Ltd. - Seoul

B09B 100

405129

A method and system for collecting and containing leachate from a landfill uses a submerged drainage sink to develop a flow pattern towards the drainage sink contained within a containment zone, and therefore minimizes the chance of contaminating area groundwater. In a first embodiment of the invention for use in a substantially flat area, a perimeter barrier wall is provided and extends downward into a bottom barrier layer, such as an aquitard, a clay layer, or a synthetic material. The barrier wall and the bottom barrier layer define a containment zone containing the drainage sink, which is disposed below the groundwater level. Leachate and groundwater are permitted to mix within the sink. The desired flow pattern towards the drainage sink is induced by collecting and removing the leachate/groundwater mixture from the drainage sink to lower the leachate level in the drainage sink to a level which is below the groundwater level outside of the wall and below the piezometric level below the sink. Although the sink is submerged, substantially all of the waste is placed above the groundwater level by covering the sink with a layer of earthen material to a level such that the top of the earthen material is above the groundwater level and placing the waste on top of the earthen material.

2012005, Mar 8, 2012

Nov 11, 2011

13/294989

Daekyoo Hwang - West Chester PA, US

B09C 1/02

40512825

A method and system for dewatering and consolidating contaminated dredged sediment concurrently as it is discharged to a disposal pond using horizontal drains installed in the settled sediment and vacuum loading. Horizontal drains are connected to a vacuum pump via collector hoses and a header pipe. Vacuum pump operation consolidates the settled sediment and reduces the volume, enabling continued discharge of dredged sediment. Successive installation of horizontal drains within accumulating sediment and consolidation by vacuum pumping may continue until the disposal pond is filled with consolidated sediment. Vacuum pumping is continued for some period after final cover installation to enhance containment performance by over-consolidation. The horizontal drain system may also be used to deliver liquid reagents for sediment treatment or to circulate water for flushing. The method enables the disposal pond to be on land or under water below the original sediment line.

5355594, Oct 18, 1994

Dec 21, 1992

7/994614

Daekyoo Hwang - West Chester PA

F26B 300

34356

A method of maximizing net water loss from various sludges in the outdoor environment to stabilize or to reduce the volume and weight of sludges. Specifically, this method comprises drying a layer of wet sludge by surface evaporation, mixing a sufficient amount of additional wet sludge to the previously-dried sludge layer to form a sludge mixture having a water content at which surface evaporation is maximized, and drying the sludge mixture by surface evaporation or by periodical tilling or both. Additionally, the sludge surface is sealed by light compaction in the event of imminent precipitation to minimize rainwater retention and infiltration. In addition to stabilization, this method may be used as an effective pretreatment step towards other sludge treatment processes to drastically reduce the sludge treatment cost, based on the reduction of the sludge volume, sludge weight, and sludge water content.