Energy efficiency in municipal waste treatment

Abstract

Abstract. The article presents the efficient method of microwave irradiation (SHF) for the municipal liquid waste such as domestic wastewater and sludge. The technical and economic parameters and experimental data, showing the possibilities of microwave electromagnetic radiation using in the sewage and sediment treatment technologies, are given in this article. The traditional electrothermal treatment and SHF processing of the municipal precipitation, taken from the city wastewater treatment plant, have been compared. At the same time, a high rate of heating of the precipitation samples has been noted during the microwave treatment. The technical and economic comparison of three methods (with the usage of the reagents, convection heating and SHF) showed the advantages of using SHF range electromagnetic radiation. The energy efficiency and the cost-effective use of resources during the SHF using for liquid municipal waste treatment have been confirmed.

Microwave Irradiation in Technologies of Wastewater and Wastewater Sludge Treatment: A Review

“…MW has become increasingly common as a thermal method for treating wastewater and sediments in recent years, owing to its rapid and selective heating [9][10][11][12][13][14][15]. The thermal effect of MW [16] describes how ultrahigh-frequency energy can be consumed by microwave absorbers and dissipated as thermal energy.…”

“…It is confirmed in the materials [25][26][27], which use the Netherlands, Kenya, China, and other countries as examples of MW-heating of faecal sludge (Figure 2). Under the influence of MW, several parameters such as strength, frequency, duration, treatment temperature, and sample volumes [9,14,[22][23][24][25][26][27] can influence the efficiency of pollutant decomposition and mineralisation of wastewater and sediments. It is confirmed in the materials [25][26][27], which use the Netherlands, Kenya, China, and other countries as examples of MW-heating of faecal sludge (Figure 2).…”

“…In some cases, the efficiency of the MW system is reduced at very high temperatures by evaporating water and increased viscosity of the substance by overheating. Thus, it is necessary to determine the optimal power and reaction temperature for decomposing a particular target pollutant [9,14,[17][18][19][20][21].…”

“…It should be noted that the technological and economic efficiency of MW heating for the water environment is currently actively explored by contrasting it to other methods of heating and processing [14,23,24]. The Department of Water Supply and Sanitation (Industrial University of Tyumen, Russia) laboratory has carried out several experiments related to the MW-heating of wastewater sludge [14,24]. Firstly, a comparison is made between microwave and electric heating.…”

“…The distinctive feature of microwave heating is its thermal effect, which is volumetric and does not involve thermal diffusion from the surface into the material, as conventional heating does, which explains its high thermoset reaction rates. According to observations, ultrahigh-frequency irradiation of liquid sewage sludge has a rapid thermal effect: samples of sludge with a 50-300 mL volume started to boil within one to two minutes (Figure 3) [14]. lated to the MW-heating of wastewater sludge [14,24].…”