Mesophilic-thermophilic fermentation process of waste activated sludge after hybrid disintegration

Abstract

Abstract:The previously received results of individual processes of hydrodynamic and alkaline disintegration were decisive significant for the conducted research task. The combination of hydrodynamic cavitation (30 minutes duration of the process) and alkaline (pH ≈ 9) to the destruction of activated sludge caused a significant release of organic matter about 1383 mg/dm 3 in comparing to individual processes. Such increase in the SCOD value resulted in a significant growth the efficiency of biogas yield in a two-stage mesophilic-thermophilic processes. The increase in yield was from 26 to 38% depending on the volume of disintegrated sludge. The effect of the two-stage fermentation resulted activated sludge hygienisation. The microbiological analysis of the influence of the fermentation with the different volume of hybrid disintegrated sludge was based on microbiological indicators: Salmonella spp. and coliphages. The obtained results prove the effectiveness of the two-stage digestion process compared to single mesophilic fermentation which not always completely eliminates the above indicators.

Improving the Gravitational Properties of Sewage Sludge by Pretreatments

“…Wśród stosowanych i badanych metod dezintegracji wykorzystuje się głównie: ozonowanie [3], alkalizowanie [10], zakwaszanie [24], użycie wysokiego ciśnienia [8], rozdrabnianie mechaniczne [16], enzymy [21], ultradźwięki [25], promieniowanie mikrofalowe [6] oraz zamrażanie/ rozmrażanie [15,19].…”

Temporal variability of sewage sludge heavy metal content from Greek wastewater treatment plants

“…The utilization of sewage sludge as soil fertilizer in agriculture is a viable solution for sustainable management of this waste material, as it involves the recycling of valuable non-toxic components (organic matter, nutrients, macroelements) and, in the same time, provides a low cost disposal option of the by-product [8,10,[15][16][17][18]24]. On one hand, this addition may represent a good alternative to prevent degradation of soils and to improve many physical, chemical and biological properties of soil [14,[25][26][27][28].…”

“…Due to the great variety of inputs and wastes in the sewer systems, wastewater contains certain undesirable components (organic, inorganic and toxic substances), and pathogenic or disease-causing micro-organisms. Sludge resulting from residential wastewater treatment processes acts as a sink of large amounts of heavy metals (cadmium, chromium, copper, mercury, nickel, lead and zinc), originated from sewage itself and sewerage pipes [4][5][6][7][8][9][10][11].…”

Waste-activated sludge disruption by dry ice: bench scale study and evaluation of heat phase transformations

“…They concern mainly the possibility of reducing the amount of sludge discharged from sewage treatment plants (Liu et al 2016; Machnicka and Grübel 2016) and improvement of susceptibility of the sludge into a biochemical decomposition (Kardos et al 2011; Wacławek et al 2016; Liu et al 2019). Disintegration is a process of destroying the structure of the sludge, which involves fragmenting of flocs, destruction of cells of microorganisms and releasing organic substances, inorganic substances and extracellular polymers into the supernatant of the sludge (Yu et al 2008; Grübel et al 2014). Sewage sludge pretreatment uses a variety of disintegration methods, such as high pressure (Gogate et al 2001; Mirota et al 2011); mechanical (Müller 2000; Wett et al 2010); microwave (Kuglarz et al 2014; Yi et al 2014); ultrasound energy (Şahinkaya and Sevimli 2013; Zhou et al 2015; Aylin Alagöz et al 2018); chemical methods—ozonisation (Ak et al 2013; Silvestre et al 2015; Carbajo et al 2016; Xu et al 2018), alkalisation (Yan et al 2013; Suschka et al 2015; Silvestri et al 2018a), acidification (Wang et al 2014; Li et al 2016; Parthiba Karthikeyan et al 2018) and oxidation technique (Zhang et al 2015; Lu et al 2016; Wacławek et al 2017; Kim et al 2018); biological methods—enzymes (Jang et al 2014; Kavitha et al 2014; Lü et al 2016; Gebreeyessus and Jenicek 2016; Ali et al 2018) and thermal methods (heat pretreatment, freezing/thawing) (Montusiewicz et al 2010; Carrère et al 2010; Nowicka and Machnicka 2015; Pilli et al 2015; Liu et al 2018); and hybrid methods (a combination of at least two disintegration techniques) (Zhang et al 2012; Uma Rani et al 2014; Grübel and Suschka 2015; Suschka and Grübel 2016; Grübel et al 2018).…”