PRESS RELEASE
October 14. 1996
New evaporation technology
for landfill leachate treatment

The first full-scale landfill leachate treatment plant using new evaporation technology has now been delivered to a waste management company located at Lahti, some 70 miles north of Helsinki, Finland.
When compared with traditional evaporation, the new technology, recently developed by Hadwaco Ltd, is reported to be economically feasible due to lower energy consumption, and lower construction and material costs.
The plant at Lahti is designed to handle about 44,000 m3 of leachate yearly at operating costs of some USD 2 per m3.

According to a study carried out in 1994 by the consulting firm Ettala & Rossi, the Hadwaco evaporation technology can successfully be applied for leachate treatment at sanitary landfills. The purification rate is high and capital and operating costs of the method are low.
The waste management company at Lahti receives about 60,000 tons of waste at the landfill site, which has an area of some 30 hectares. With this amount of waste, the leachate discharge needed to be treated at the site is about 30,000 m3 per annum.
The new evaporator concept is based on mechanical vapour recompression (MVR) and the falling film principle. The heart of the concept is a special heat transfer surface design that employs high quality polymeric materials. By using such materials, large heat transfer areas can be constructed at significantly lower cost, when compared with metallic surfaces of the same size. A large heat transfer surface results in low energy consumption, about 8-10 kWh/m3 with the new evaporator.
At the Lahti plant, the leachate feed to the evaporation system is 130 m3 a day. After purification, 120 m3 of clean water – the condensate – is conducted into the environment. The concentrate amounting to 10 m3 a day is returned to the landfill body.
The waste management company in Lahti assumes full responsibility for its environmental effluents, including landfill leachate. By using the Hadwaco evaporation technology, the company also fulfils the most stringent stipulations concerning landfills within the European Union area.
In addition to sanitary landfills, the new technology can also be used for the treatment of waste water in the pulp and paper, food stuffs and metal industry, and for the preparation of fresh process water from low-quality ground water./ins



Caption:

The first leachate treatment plant using new Hadwaco evaporation technology commenced operations in June this year in Finland. According to studies, the plant is more economic than conventional evaporation plants due to lower energy consumption and low capital and running costs.



For further information, please contact:

Hadwaco Ltd Oy
Mr. Peter Koistinen or Mr. Erkki Kasanen
Hämeentie 135, FIN-00560 HELSINKI
Tel. +358 204 3911, fax. +358 204 39 5655








Technical details

Technical data for the plant:
Leachate handling capacity: 44,000 m3/a
Leachate to be treated today: 30,000 m3/a
Leachate feed: 130 m3/d
Purified water: 120 m3/d
Concentrate to be returned: 10 m3/d
Energy consumption: 10 kWh/m3
Operating pressure: 0.12 bar
Operating temperature: 50 °C

Properties of the purified water:
Ammonium concentration: < 2 mg NH4-N/l
CODCr: < 30 mg O2/l
Conductivity: < 5 mS/m
(Results obtained on the installed plant at the Lahti landfill)