Crystals Beat Floc — Better Dewatering with Neo WaterFX
Removing phosphorus from wastewater can create large quantities of difficult to dewater sludge, driving up disposal costs. The cause is choosing the wrong coagulant. Traditional coagulants, iron or aluminum based, are not selective for phosphorus and only bond weakly with it. It can often take at least 4 molecules of coagulant to trap just one phosphate molecule, and if your limits are low, less than 0.5 mg/L, that ratio can go even higher. That alone creates a lot of additional chemical sludge.
Bound water is the other issue. Phosphorus removal using these traditional chemicals functions through floc formation rather than actual bonding, and that floc traps a lot of water. All that bound water is difficult to remove in the dewatering processes like gravity belt thickeners or belt filter presses. To break the floc’s hold on the water, you may have to add large amounts of polymer filter aids. This can help remove the water but adds even more weight to the sludge and slows down dewatering. Even with high polymer addition the results are often disappointing, with wetter solids that cost more for disposal.
Neo WaterFX is different
|Treatment without Neo WaterFX||Results with Neo WaterFX|
Neo WaterFX has a strong attraction for phosphorus and bonds tightly with it. The attraction and selectivity are so strong that WaterFX can be fed in a 1:1 ratio with the phosphorus and can achieve extremely low limits, well under 1 mg/L and in most cases, even below 0.1 mg/L. This dramatically reduces the amount of chemical sludge requiring dewatering. Even better, the resulting compound is a dense crystal that settles quickly and does not trap water. Clients who make the switch report not only less sludge volume but that the sludge requires less polymer feed to achieve excellent dewatering. With less bound water, the final solids are drier.
In addition to achieving drier sludge with less polymer, clients are often able to reduce the filter run times and the energy costs associated with dewatering. Sludge disposal costs are reduced because there is less chemical sludge to begin with and the final cake contains less water. Cost savings can be substantial.
So, to recap the operational and financial benefits of making the switch to WaterFX
WaterFX improves dewatering by:
- Producing less chemical sludge due to less coagulant needed to achieve low phosphorus effluent levels,
- Creating denser sludge due to crystalline nature of the bond between WaterFX and phosphate,
- Less bound water for a drier sludge to send to dewatering,
- Less polymer needed to achieve dewatering,
- Lower overall sludge volume, and
- Quicker sludge processing for shorter belt filter runs.
All of which add up to sludge processing and disposal cost savings.