EN Decision director Dr Wei Chen wants enforceable sewage rules and warns type-approvals have enabled invalid shipboard systems
EN Decision director Dr Wei Chen argues IMO’s current approach to sewage regulation needs a fundamental shift towards evidence-based enforcement, warning approval regimes have allowed ’invalid’ sewage treatment plants (STPs) to persist on ships.
He was speaking ahead of his appearance on Riviera’s Greywater and blackwater: improving the compliance gap webinar, which takes place on 30 October between 09:00 and 10:00 GMT.
Dr Chen traces his trajectory from land-based wastewater to two decades in maritime environmental engineering and regulation.
He said the turning point was Alaska’s cruise discharge regime, “Since 2000, state regulations have enforced compliant discharge performance from large cruise ships through independent sampling.”
He describes these as “evidence-based regulations,” adding advanced wastewater treatment systems were developed and optimised “achieving consistent, compliant discharge performance with a proven track record.”
Reflecting on that period, Dr Chen said the contrast with wider shipping remains stark.
“As it turned out, the evidence-based regulations in Alaska are the only ones in the marine world. The rest of the shipping industry is regulated by type-approval regimes that are not supported by effective enforcement of compliant discharges,” he said.
He first confronted this gap between the advanced water treatment systems developed for Alaska and STPs when leading testing and an approval application for a sewage treatment plant under an updated MEPC resolution.
He noted legacy STPs were grandfathered and new STPs tested under lab conditions “performed no better on ships,” with many “discharging virtually raw sewage.”
He said it took courage to state the obvious: elsewhere in society, approval-centred models have largely been replaced by monitoring and enforcement.
“Since the 1970s, our society has abandoned the tried and failed approval-based regulations and shifted towards evidence-based regulations.”
Shipping, in his view, “remains stuck in the distant past.”
