ACHIEVING WASTEWATER TREATMENT SUSTAINABILITY THROUGH MANAGEMENT OF BIOSOLIDS
A review of two wastewater treatment plants in the United States
A Cooper, W Bailey, C Rogers, D Solley, M Laginestra

Wastewater treatment represents significant energy consumption, and authorities are becoming increasingly aware of the need to provide sustainable services. Biosolids management at WWTPs offers the opportunity to achieve energy sustainability through anaerobic digestion. This paper looks at two agencies in the US largely achieving sustainability.

Blue Plains WWTP (1,400 ML/d) DC Water, Washington, encountered rapidly escalating costs in 2006 and new digestion facilities were placed on hold. After a strategic development investigation plant management proceeded with Thermal Hydrolysis and Mesophilic Anaerobic Digestion, dramatically reducing construction and O&M costs, and involving generation of 13 MW of power.

Hill Canyon Treatment Plant (50 ML/d) In 2006 the plant operations team began an aggressive energy conservation program to enable 50% of the plant’s needs to be met by power production from biogas. Additional energy was provided by solar panels (150 kW) and upsized cogeneration (700 kW). To ensure adequate production of digester gas, HCTP treats a variety of high-strength waste streams, and now achieves 100% production of its energy usage.

Some Australian authorities are also looking at WWTP biosolids sustainability aspects and a summary of achievements is outlined.

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