International Dredging Review

International Dredging Review

Dragflow has recently delivered a small remote-controlled dredge the DRP18 to Candeo Agostino of Padova Italy as part of the remediation program at Momentive an internationally known chemical company with an important presence in Italy. Candeo Agostino is in the field of cleaning and environmental hygiene with ecological interventions for small medium and large users for civil and industrial applications. The company conducts environmental inspections and analyses including sludge dewatering water filtration transport and disposal of waste.

As part of Momentive’s remediation program Candeo Agostino was required to collect mud from two equalization ponds after which the sludge was sent to the press filter and the disposal process continued. Because of the nature of the sludge safety demands were very specific: The operation had to be conducted without emptying the collection pond; the plastic lining in the bottom of the pond had to be protected; and operators had to be well protected from the liquid acidity in the pond. 

Dragflow’s DRP18 was able to resolve these issues. Thanks to the remote control operation of the dredge there is no operator onboard. In addition because of the ability to calculate the exact working depth of the pump plus the maneuverability of the dredge the operation can be conducted with complete safety. Using the remote control device the operator is close enough to poolside to have visual contact and still work at a safe distance of up to 250 meters (820 feet) Dragflow said.


The DRP18 with a submersible pump at work in the sludge pond.

The dredge measures 3.5 meters (16 feet 5 inches) in length 2.8 meters (14 feet one inch) in width and three meters (9 feet 10 inches) in height and weighs four tons. It has two pontoons 3.5 meters x one meter x 1.25 meters with a central platform with a draft of 80-90 centimeters (33.3 to 3.75 inches) and a working depth of up to 30 meters (98 feet). The dredge’s small size makes it is easy to transport by truck to the work site. Once on site it is easy to assemble and deploy using the hand-held remote control.   

The dredge is equipped with electric pump EL75S  with power up to 100 mc/h that can be increased if necessary to 13 kW and 140 mc/h. If the dimensions are changed the DRP18 can reach 1000 mc/h. An acid-resistant package is also available. In this case at the request of the client an explosimeter was placed on-board the dredge. An explosimeter is a tool that detects an explosive environment and sends a signal that automatically turns the dredge off. 

The DRP18 dredge is a cable dredge based on a submersible pump. It was designed with the thought in mind that bodies of water such as ponds lagoons dams and canals should be maintained to maximize their operational efficiency. Sludge levels should be regularly man-aged as excessive sludge results in overloading and poor pond performances. Dragflow said the capital operational and maintenance costs of using this mini-dredge are very competitive compared to traditional methods for sludge removal from ponds and lagoons making hydraulic dredging easier and more effective.

Dragflow said the  portable mini-dredge has previously proven its value in harbor and marina dredging in natural bodies of water as well as in channel and pond cleaning and in mining. This is the first time the dredge has been used for re-mediation in the chemical industry. Configured as a remote control dredge the DRP becomes an automated system reducing the cost of operation while improving productivity. 

At Momentive the Dragflow remote-con-trolled dredge has been able to pump all the sediment lowering the level of sludge by two meters (6.5 feet) in a matter of minutes. Candeo Agostino has an ongoing maintenance contract with the Momentive plant for sludge removal. With the DRP18 they are able to work continuously according to the needs of the chemical plant.