Renewi, the international waste-to-product business, doubled its underlying pre-tax profit in the six months to 30 September to £34.2 million.
The statutory profit before tax was £22.2m, compared with a loss of £0.9 million the year before.
Revenue on a pro forma basis increased by 4% at constant currency to £782.9m, and was up 11% at actual rates.
Underlying EBIT, on a pro forma basis, rose 21% at constant currency.
Commercial Waste performed particularly strongly, with underlying EBIT up 38% to £36.2m.
Netherlands underlying EBIT grew by 73% on revenue up 7% as a result of improving economic growth and construction market recovery.
Hazardous Waste underlying EBIT was up 5% to £13.7m, while Monostreams underlying EBIT increased by 29% to £9.5m.
Municipal recorded an operating loss of £4.9m due to continued market headwinds and contractual constraints. Underlying progress in the UK was offset by the loss of subsidies at Wakefield and lack of feedstock at Westcott Park.
Peter Dilnot, chief executive officer, said: "We are pleased to report a very strong first half performance for Renewi, driven by good operational performance, improving end markets in our Benelux divisions, and earlier than expected merger benefits. Against this backdrop, we announced on 23 October 2017 that our expectations for the full year ending 31 March 2018 had significantly increased.
"We have made good progress with our integration and the transition to one unified operating model. We remain on track with the target synergies and delivering significant value accretion from the merger in the year ending 31 March 2019 and thereafter. Longer term, Renewi is well placed to meet the growing need for recycling with a clear strategy to deliver sustainable growth, margin expansion and attractive returns."
At 8:15am: (LON:RWI) Renewi Plc share price was -0.35p at 106.95p