The Secrets of Sludge

Wastewater treatment involves several fundamental components: physical treatment (i.e.) screening and filtering processes), biological treatment (i.e.) oxidation ponds and lagoons), and chemicals. The chemicals required for water treatment must be used more aggressively and in larger quantities for wastewater than municipal drinking water. Verily, safe, effective storage for wastewater treatment chemicals is critical.

There are five basic steps for the wastewater treatment process, each of which involves a set of familiar chemicals. The five steps are as follows: removal of solid particles, neutralization, odor control, disinfection, and sludge treatment and removal. We will now delve deeper into sludge removal and the commonly used chemicals used in the process.

What is Sludge?

Sewage sludge is composed of both inorganic and organic materials, large concentrations of plant nutrients, much smaller concentrations of trace elements and organic chemicals, and pathogens. The compositions of sewage sludge vary considerably depending on the wastewater composition and the treatment processes used.

Why Sludge Removal Is Essential

Wastewater treatment produces sludge in both on-site (i.e., septic tank) and off-site (i.e., activated sludge) systems. As wastewater treatment removes solids from wastewater, it is inevitable that sludge will remain. Sludge characteristics can vary significantly from fairly fresh fecal materials, which contain large quantities of pathogens, to fecal matter that has decomposed over the course of time, which contains fewer pathogens, as many of them have already died off. Sludge treatment methodologies are highly dependent on the specific characteristics of the sludge.

Before going through final disposal, sludge must be treated to bring down the volume and stabilize the organic materials. Stabilized sludge does not possess harsh odors and can be handled without risk of safety hazards. Smaller volumes result in lower costs for sludge storage, sludge pumping, and sludge disposal.

What are the options for Sludge Removal?

The assorted options for treating sludge include stabilization, thickening, dewatering, drying, and incineration. Treating sludge and removing sludge from wastewater have roughly similar pricing.  Typically, a polymer chemical is used for the volume reduction process known as dewatering. On another note, the presence of polymers increases facility slip and fall risks because polymers are slippery chemicals.  Additionally, polymers can be environmental stress crack agents.

Dewatering sludge decreases liquid volume by as much as 90 percent. Digested sludge is put through hefty centrifuges that work very similarly to a washing machine spin cycle. The spinning centrifuge produces a force that separates the majority of the water from the sludge solid, creating a biosolid material. The water pulled from the spinning process is sent back to the plant for reprocessing. Inserting polymer chemical to the substance enhances the consistency, creating a firmer product with increased manageability. The biosolid cake consists of between 25 and 27 percent solid material.

Waste Water Treatment Devoid of Sludge

Certain microbes are capable of eating sludge and other unwanted elements in the waste water process which can not only eliminate sludge, but also chemicals. Chemical free solutions can be safer and more cost effective while producing no odor in the effluent. Sludge free water treatment solutions are rapidly growing in popularity due to reduced operations costs.


Contact Falcon Project Consultants for help with your waste water applications.