The past decade alone showed the rapidly declining state of the environment. This resulted to wastewater treatment plants focusing its attention on collecting and treating wastewater prior to discharging it to the environment. The processes used on the wastewater unintentionally produce a sludge material made up of pathogens, pollutants, and other substances originally found on the wastewater material. This is where biosolids management must take a lead role.
The sludge material is too polluted and too harmful to even be discharged to the environment. And that is why regulations have been put in place to also start processing this sludge material and turn it into a usable form of fertilizer or in many cases, organic soil. Historically, not much thought has been given to the processing and the treatment of this sludge material. But further studies and researches found out that using the treated sludge material is economical and even ecological.
What is sludge? How was it disposed before treatment?
Sludge is a wet material that is a by-product of wastewater treatment processes. It is very expensive to transport and does not compact very well. Pollution-wise, it may contain a considerable amount of pathogens and other substances that are not only harmful to the environment, but to humans as well. It may also contain heavy metals that could affect the viability of the soil for gardening, vegetation, crops, and other consumable functions.
Sludge material also gives off an undesirable odor, making it unbearable for those in the community where the sludge material treatment plant is. Moreover, the disposal of sludge material is almost near to impossible because of its bad odor.
Before it was able to be transformed into organic soil, sludge material was land applied on local farms or dumped in landfill sites. However, such practices are now under scrutiny and they are being frowned upon by environmentalists and government regulatory boards. In many parts of the country, these practices have already been banned. This means that these states and municipalities have to find a way to further treat this material. They are now being required to transform the sludge material into something useful and even beneficial to the environment.
How is sludge material being treated nowadays?
To turn the sludge material into something viable for consumption, the moisture content, volume of pathogens, and overall odors must be reduced. Whatever solids that remained in the sludge material must also be increased through its calorific value and biological stability.
Once these conditions are completed, the product must be a dry biosolid that can be reused as fuel in Waste-to-Energy plants, coal-fired power plants, or cement kilns. It must also be “good enough” to be a fertilizer for agricultural use, or Class A land application. The final requirement of biosolids management is for the wet volume of the sludge material to reduced so that only dried biosolids will remain. In turn, these can reduce handling and hauling costs.