Effluent Treatment Plant for Statoil's Methanol Plant, Tjelbergodden, Norway
Introduction
The contract to design, supervise construction, seed and commission the plant and train operators and maintenance personnel at Tjelbergodden in Norway has recently been successfully completed on time and within budget by Microbac Limited.
Treatment
In conjunction with their distributor in Norway, Bioscan Norge A/S, who procured all of the mechanical equipment for the ETP and managed the sub-contract for the project's main contractor, Fluor Daniel, Microbac have supplied a complete treatment system capable of degrading all of the liquid wastes produced by the Methanol Plant and its associated Air Fractionation Plant. The resulting treated effluent satisfies the strict discharge consent requirements imposed by the regulatory authority, SFT, in terms of organic loading, ammonia, phosphate and suspended solids.
The submerged, aerated, fixed-film Bioreactor and Filter Units allow a wide range of wastewater to be treated on a semi-automatic basis with minimal operator interference. Site waste liquids treated include methanol from scrubbers and spills, ammonia and formates from process areas, saturator blowdown, distillation column bottoms, oil leaks and polyol spills as well as all of the domestic sewage produced on the site.
The plant consists of a Lift Station where all incoming wastes are thoroughly mixed, pH is adjusted and nutrients balanced. This is followed by a Feed Chamber and Primary Settlement Tank. The effluent is then heated and passes into the Bioreactors where organics and ammonia are degraded utilising specifically adapted environmental bacteria in conjunction with a novel aeration system. The plant is covered so that it can operate in temperatures down to minus 20oC and in deep snow conditions.
A utilities building houses the blowers as well as the acid and alkali dosing systems for pH adjustment, the nutrient dosing systems to promote optimal biological activity and the coagulant and flocculant dosing systems to assist in the separation of solids.
Automation of the plant is such that a single operator can supervise the whole ETP as a part of their daily duties.
Results
Microbac's capabilities utilising in-house design and NAMAS accredited testing laboratories, effective degradative bacterial cultures, commissioning and training have ensured that the plant is operating comfortably at its design criteria and is meeting all required discharge consents.