Pilot-Scale Polyhydroxyalkanoate Production from Combined Treatment of Organic Fraction of Municipal Solid Waste and Sewage Sludge

Although the organic fraction of solid waste (OFMSW) and sewage sludge (SS) originate from the same urban area and contain similar organic matter, are collected separately and handled with different technologies. In this work, a combined treatment of OFMSW-SS mixture was investigated at pilot scale, by using a three-step mixed microbial culture (MMC) process in order to produce polyhydroxyalkanoate (PHA) as final high value biobased product. Biomass selection efficiency was quantified by PHA-specific storage rate that was 258 mg CODPHA/g CODXa/h under the optimized process condition. In fed-batch tests, PHA-storing MMC was able to accumulate up to 46 wt % PHA. In the perspective of a full-scale application and taking into account the mass flows in each process step, an overall yield of 65 g PHA/kg TVS was estimated.