Deponie Obwalden AG, a landfill site, is situated in the hilly landscape of Sarner Aatal, a couple of minutes by road from Kerns. Run by the operator Melk Durrer AG from Kägiswil, the landfill site accepts all waste of type A (excavated material) as well as type B (inert materials) as per the Swiss Ordinance on the Avoidance and Disposal of Waste (VVEA). True to its motto "Disposal made easy", both businesses and private individuals from the Swiss Canton of Obwalden can use the landfill site.
Saving in landfill volume
The team at Melk Durrer AG had long held the idea of a washing plant for processing excavated material with the goal of saving landfill volume. Along with this basic idea, the team also set itself the task of making a contribution to the conservation of resources. For this reason the excavated material is not dumped in the landfill site, instead it is recycled to obtain high-quality mineral end-products. It was against this background that the first meeting with GIPO AG was held. Starting from considerations about making the production process more intelligent, economical and sustainable, an enhanced stationary GIPOWASH wet processing plant was produced, exactly tailored to the wishes of this customer. This plant also includes the complete water and sludge processing system WSA.
The compact, efficient plant for washing excavated material meets the latest requirements as well as all Swiss safety requirements and regulations. Due to the automatic control system, the plant requires only one person to operate it. As such, the plant operator can monitor the individual machine components while feeding material to the plant at the same time. This high efficiency ensures cost-effective, sustainable production. The GIPOWASH plant impresses with its reliability, and our prompt GIPO Service guarantees the high availability of wearing and spare parts. Our in-house engineering and subsequent manufacture in our production facilities in Seedorf UR are a major advantage. There are almost no limits to the size of the excavated material washing plants.
Bespoke plant
The plant has five different base slab levels to suit the space available. A tracked GIPO screening machine of type GS 144 2-deck feeds the material. The removal of the magnetic conveyor is straightforward, making it possible to transport the screening machine quickly. This customer wish allows the screening machine to be used flexibly on external construction sites; the high-capacity excavated material storage facility on the site means production using the wet processing plant can be interrupted for extended periods.
The washing process starts on a one or two-deck pre-washing screen. The material then passes through mechanical processing in the double-shaft log washer. The throughput time in the water tank is matched to the material soiling by the optimal inclination and the variably adjustable rotational speed of the two shafts. An overflow channel transports the undesirable impurities out of the log washer to the light material screen. From there, the impurities are dewatered before they pass to the collecting container.
The clean aggregates obtained are transported to a screening machine after passing through an additional final washing unit with a further dewatering screen. The size and number of decks in the screening machine can be selected to suit the required fraction. Chutes and conveyor belts transport the dewatered components to gravel boxes or dosing plants. The extraction of sand fractions in two different sizes using cyclones ensures maximum dewatering with a precise separation cut of 0.063 mm.
The water and sludge processing system WSA is assisted in the high clarifier by an automatic flocculent dosing station and the sedimentation process. The dewaterable, pre-thickened sludge is dewatered in the chamber filter press by the application of pressure. The washing process is fully automatic. The clean process water can then be reused in the closed circuit. As such ecological, water-saving closed-circuit management is implemented. The economic benefit is apparent in the sand and gravel products, as well as in the quantity of residual material that needs to be finally dumped in the landfill as filter cake.
The customer profits from GIPO's incomparable know-how and our flexibility during design, combined with high plant availability thanks to our prompt GIPO Service. As such we are able to manufacture in our own works, install and handover a complete, turn-key GIPO excavated material washing plant tailored to the customer. With only one general contractor as their contact partner, working together with the supplier is easier for the customer permitting the implementation of any special wishes or even last-minute changes on schedule.
Technical plant data
Feed material:
Excavated material, railway ballast, quarry waste
End products:
Sand: 0/1, 1/4 mm
Gravel: 4/8, 8/16, 16/32, 32/63 mm
Feed volume:
Performance approx. 80 metric t/h with 20 % fine portion <0.063 mm
Process water tank capacity:
50,000 ltr.
Clarifying tower capacity:
220,000 ltr. (Sludge buffer 130,000 ltr.)
Loading:
Using excavator or wheel loader