Treating and reusing wastewater generated by the washing operations in the non-hazardous plastic solid waste...

Area of Science:

• Environmental Engineering
• Water Treatment Technologies
• Waste Management

Background:

• Wastewater from washing non-hazardous plastic solid waste (PSW) presents disposal challenges, particularly the large sludge volumes generated by conventional activated sludge processes.
• Recuperi Pugliesi, a plastic recycling company, faces issues with sludge production from washing low-density polyethylene (LDPE) waste.

Purpose of the Study:

• To assess the effectiveness of an advanced Sequencing Batch Biofilter Granular Reactor (SBBGR) for treating PSW washing wastewater.
• To compare the SBBGR treatment with the conventional activated sludge process in terms of removal efficiencies, sludge production, and cost-effectiveness.

Main Methods:

• The study evaluated the SBBGR's performance under steady-state conditions, measuring key parameters like COD, BOD5, TKN, TSS, VSS, NH3, and TN.
• Effluent quality was modeled using generalized additive models (GAMs) based on washing water characteristics.
• A direct comparison was made with the conventional treatment process used by Recuperi Pugliesi.

Main Results:

• The SBBGR demonstrated high removal efficiencies: over 90% for COD and TKN, over 99% for BOD5, TSS, VSS, and NH3, and over 80% for TN.
• SBBGR effluent quality was statistically superior to the conventional treatment.
• Specific sludge production was five times lower with SBBGR (0.21 kg TSS/m³ vs. 1.0 kg TSS/m³).

Conclusions:

• The SBBGR is a highly effective advanced wastewater treatment for PSW washing, offering superior effluent quality.
• The SBBGR significantly reduces sludge production, leading to a five-fold decrease in sludge disposal costs and a 50% reduction in overall operating costs.
• This advanced treatment presents a more sustainable and cost-effective solution for managing wastewater in the plastic recycling industry.