Description: Driving the Upgrade Ramp
Figure 1 (p. 44) shows biosolids products that can be generated from solids processing and the specific beneficial end use or disposal markets for each product. After stabilization, biosolids products can be processed into Class B cake, Class A cake, Class A dried material, Class A compost, and biochar/ash. The beneficial end use markets for these products are agriculture, energy, land...
PublisherWater Environment Federation
Word count199
Description: Driving the Upgrade Ramp
Figure 2 (p. 45) describes the biosolids decision-making road map for generating various products for disposal or beneficial use. The following sections describe the pressures on utilities to produce different types of biosolids. In general, these pressures push the treatment needed up the scale of complexity and expense. It should be noted that a WRRF that is producing unstabilized solids can...
PublisherWater Environment Federation
Word count82
Description: Driving the Upgrade Ramp
Landfill disposal of residuals requires dewatered material and remains a viable option for WRRFs in many geographic locations. However, a national trend is emerging that could limit acceptance of dewatered residuals by landfills and/or phasing out landfilling altogether. Some WRRFs practicing landfilling recently have received notification from landfill operators describing facility operational...
PublisherWater Environment Federation
Word count342
Description: Driving the Upgrade Ramp
Producing Class B biosolids requires practicing stabilization technologies, such as anaerobic digestion, aerobic digestion, lime stabilization or other chemical stabilization. Anaerobic digestion is the most common method of solids stabilization in the U.S. to achieve Class B pathogen reduction and provides opportunities for energy recovery and reducing biosolids mass. Moving to producing Class B...
PublisherWater Environment Federation
Word count241
Description: Driving the Upgrade Ramp
Due to the above pressures on Class B beneficial use, some WRRFs already are producing Class A biosolids while others seriously are considering adapting technologies to produce Class A, which requires large capital investment. The technologies producing Class A biosolids can be advanced anaerobic digestion (e.g., thermal hydrolysis pretreatment, temperature phase anaerobic digestion, enhanced...
PublisherWater Environment Federation
Word count280
Description: Driving the Upgrade Ramp
The publication of the EPA OIG report in November 2018 will have ramifications for the future practice of bulk land application. The report identified more than 300 pollutants in biosolids that are not currently regulated by EPA that could pose a human and environmental health risk because of biosolids land application. EPA agreed to study the risk from these pollutants when practicing biosolids...
PublisherWater Environment Federation
Word count146
Description: Driving the Upgrade Ramp
PFAS compounds are ubiquitous in nature and have been detected in biosolids products at various levels. These compounds tend to favor sorption into the solid matrix after entering WRRFs, thus concentrating in the solids and biosolids products. None of the existing commonly applied stabilization technologies to convert solids to biosolids remove PFAS. Therefore, practicing land application of...
PublisherWater Environment Federation
Word count457
Description: Driving the Upgrade Ramp
Considering all the pressures on biosolids land application programs, some utilities are moving to advanced thermal processing technologies, such as gasification and/or pyrolysis, that do not produce “biosolids” for land and produce ash or biochar. Figure 3 (above) shows a schematic diagram of the pyrolysis process, which operates at an elevated temperature ranging from 199°C to...
PublisherWater Environment Federation
Word count244
Description: Driving the Upgrade Ramp
Figure 4 (below) shows an example of a trigger-based, decision-making road map for a recently completed master plan at a 75,700-m3/d (20-mgd) facility that currently only dewaters and hauls unstabilized solids to a nearby landfill. The landfill has capacity issues and the owner of the landfill has been complaining of odor from the solids and workability with the solids waste material...
PublisherWater Environment Federation
Word count349
Driving the Upgrade Ramp