Sand, gravel, inorganic, and organic particles are key components known as 'grit' to wastewater treatment plant operators. Grit is essentially anything that finds its way into the plant that cannot be treated by any secondary or a sludge treatment process. Grit finds its way into wastewater treatment plants in a variety of ways, such as: stormwater, directly from the homes where items are flushed down the toilet and shoved down the kitchen sink drain, infiltration into broken pipes and manholes, and even from the within the wastewater treatment facility. Why is grit a problem? Operators struggle to manage grit because it clogs wastewater systems filling up tanks and aeration basins, reducing treatment effectiveness and causing down-time in the facility and damage to wastewater equipment.
"Removing grit at the front end of your plant lessens the chance for damaged equipment, pipes, pumps, filters, and diffusers. Grit removal technology is the best investment you can make to ensure the longevity of your wastewater facility" - Paul Nygaard, President of ICS Group.
If you are ready to 'grit' down to business, here are the essential pieces of equipment to remove grit:
Screening (coarse screens, fine screens)
Grinders
Grit removal (classification and vortex chambers)
Screening
Screening wastewater as it immediately enters your facility is your first defense for grit. Wastewater that contains larger organic or inorganic materials will be screened to remove the debris from the influent water. Coarse and fine screening is available to capture both large and small organic or inorganic materials. Coarse screening typically requires an operator to manually remove the debris from the screen, while the fine screening captures smaller items in filters.
Screening Solutions:
Kusters Water offers a variety of screening technologies for municipal facilities to solve complex problems, such as: high levels of hydrogen sulfide (H2S), various levels of organic loads (BOD) and elevated levels of Fats, Oil & Grease (FOG).
The Kusters Water Multi-Rake Bar Screen was developed with the toughest pre-treatment problems in mind. Kusters Water has modified a basic design of conventional bar screens to a better product for wastewater facilities. Features of the Kusters Water Multi-Rake Bar Screen: combination of fine and coarse screening with high solids capture rates, robust construction, long life, and low O&M costs.
The Perforated Plate Filter Screen cuts down on operational issues caused by fibrous and other inorganic material. The quality of the screened effluent is noticeably better, which improves your facilities performance and protects downstream wastewater equipment.
The vertical ProTechtor® Centerflow Band Screen is excellent for wastewater facilities with a compact footprint and limited headspace. Influent flow enters the screen in the middle of the screen frame and is positively screened as the flow transitions from the inside and passes through the traveling perforated filter belt through the sides and bottom. Optimally spaced lifting tines are attached to filter panels to capture and elevate larger items to the internal discharge point. Screenings are washed off via spray headers and/or a combined motorized brush assembly and are discharged to an internal flume or screenings washer compactor, which transports the screenings outside of the screen frame. The quality of the screened effluent is drastically improved which in turn improves facility performance and better protects downstream wastewater equipment.
The Primescreen® is a self-cleaning conical disk filtration system which provides the benefits of primary clarification in a fraction of the traditional footprint and civil cost.
The installation of Primescreen® allows the plant to obtain immediate energy savings due to the reduction of Total Suspended Solids, BOD and COD, decreasing the aeration requirements in the processes after the primary treatment.
How do you handle the debris that is collected on the screen? Simple answer. The Kusters Water wash compactor. This wash compactor is synonymous with hygienic and efficient handling of screenings. The Kusters Water wash compactor reduces the weight and volume of the screenings while washing out more than 95% of fecal matter. Kusters Water wash compactors provide high performance combined with low operating costs to provide an excellent cost/performance ratio.
Grinders:
If grit gets past your screening system, wastewater plants may choose to install a grinder to chop up organic and organic materials. The ICS Group partners with Muffin Monster and Myono.
Grit Removal Solutions:
If your wastewater team worries about grit settling and the complete removal of grit from your wastewater facility, Fluidyne offers three grit removal technology options.
Fluidyne’s Hydro-Grit™ grit vortex system removes sand and inorganic material before the wastewater treatment process. This grit removal technology is historically one of the most popular and effective Fluidyne products. Performance data with the high-efficiency grit removal unit has shown 95% removal of all grit 74 micron and larger.
Using a combination of inlet feed stream energy and auxiliary water jet energy, the Fluidyne Hydro-Grit™ vortex grit separation system is unique in design and the benefits provided, yet the principles of its operation are well-proven. Grit and other heavy particles are separated, washed and removed from liquid streams effectively and efficiently. The Hydro-Grit™ system is all-hydraulic, non-mechanical and non-clogging.
The Hydro-Grit™ Classifier is designed for the separation, dewatering and removal of settleable inorganic material typically at the inlet/headworks of a municipal or industrial wastewater treatment plant. In conclusion, grit does not need to be a problem at your wastewater treatment plant. With the right combination of grit removal technologies, you can completely remove a variety of grit at the front-end of your facility. If you are interested in installing new equipment or upgrading an outdated grit removal system, please reach out to the team at ICS Group.