As Centrisys/CNP Regional Sales Manager, Josh Benoit covers the southeastern states to help municipalities increase uptime, optimize performance and reduce service and maintenance costs. Previously, Benoit was an applications engineer for four years where he gained crucial knowledge of our available processes and how to aid engineers, contractors and end-users in building a successful and economical installation. Benoit attended the University of Maryland-Baltimore County and earned a Chemical Engineering degree with a concentration in Environmental Engineering

Waste Activated Sludge mostly consists of bacterial biomass and due to its poor compaction characteristics tends to have a solids content of 0.8 to 1.2%. Thickening of waste activated sludge would reduce the downstream equipment size, energy requirements, and chemical inputs. There are number of technologies on the market to achieve sludge thickening such as dissolved air floatation, gravity belt thickener, rotary drum thickener, and thickening centrifuges. Furthermore, thickening centrifuges can be divided into modified dewatering centrifuges and centrifuges developed specifically for thickening process, such as Centrisys THK sludge thickeners. Traditionally, solids capture, and sludge thickness achieved has been the key determining factors for selecting a sludge thickening process. However, recent years following factors has emerged as considerations.

Polymer supply disruption:

Difficulties in securing polymer due to supply chain challenges has led some municipalities to evaluate the resiliency of their plant’s dewatering and thickening operations. Thickening equipment that minimizes polymer usage has become a consideration in the equipment selection and sizing process.

Side stream flow minimalization:

More utilities are investigating side stream treatment processes to reduce the nutrient loads to comply with more stringent nutrient discharge limits. Reducing side stream flow volumes through thickening would reduce the capital and operating expenditures of the side stream treatment processes.

Footprint reduction:

For thickening and dewatering equipment, the building expansion often costs more than the equipment itself. The ability to maintain or reduce the equipment footprint can have large economic implications on total plant upgrade project costs.

Equipment consolidations:

Finding qualified operators and maintenance personnel is a major challenge for water/wastewater utilities. One consideration Municipalities will begin evaluating is high efficiency thickening equipment that can thicken more as compared to lower capacity thickening equipment that would require more units. The fewer units required to maintain, the less involvement by maintenance staff which helps alleviate short-staffing challenges.

In this presentation, the case studies reviewed will highlight how five thickening alternatives would compare for these new emerging selection criteria and how the expanded equipment selection criteria could incorporate.