New device for air disinfection with a shielded UV radiation and ozone

A. Martinovs¹*, L. Mezule², R. Revalds¹, V. Pizica¹, V. Denisova², A. Skudra³, G. Kolcs¹, E. Zaicevs¹ and T. Juhna²

¹Rezekne Academy of Technologies, Faculty of Engineering, Atbrivosanas aleja 115, LV-4601 Rezekne, Latvia
²Riga Technical University, Water Research and Environmental Biotechnology laboratory, P.V. Valdena 1-303, LV-1048 Riga, Latvia
³University of Latvia, Institute of Atomic Physics and Spectroscopy, Jelgavas iela 3, LV-1004 Riga, Latvia
*Correspondence: andris.martinovs@rta.lv

Abstract:

Indoor air disinfection has become particularly relevant recently because of the Covid-19 pandemics. A shielded device for air and surface disinfection with UV radiation and ozone has been developed. It contains 28 low intensity (11 W) UV lamps (254 nm) in a specially designed three-dimensional grid to provide a large flow cross-sectional area and long path for the air particles to be irradiated. The device can be used in medical institutions, veterinary clinics, manufacturing plants, public premises, poultry, and livestock farms. It does not generate air-ions and ozone concentrations do not exceed the allowed 8-hour average values. The large number of UV lamps and powerful fans ensure air disinfection in large rooms in a relatively short time (400 m3 h-1). Simultaneously, the floor surface under the appliance is disinfected. Disinfection efficiency tests demonstrated 99.9999% reduction for Escherichia coli, Staphylococcus aureus and Pseudomonas phage Φ6 aerosols within a single transfer through the system (10 seconds of treatment). The housing of the device protects from direct UV radiation; therefore, people can be in the room during the operation of the device.

Key words:

Disinfection of solid fraction of cattle manure in drum-type bio-fermenter

R. Uvarov*, A. Briukhanov, I. Subbotin and E. Shalavina

Institute for Engineering and Environmental Problems in Agricultural Production (IEEP), Filtrovskoye sh., 3, Tyarlevo, g. RU196625 Sankt-Peterburg, Russia
*Correspondence: rauvarov@gmail.com

Abstract:

In the context of increased intensification of production and disruption of established ties between livestock and crop farms there is an urgent need to introduce novel, more efficient, economically viable and environmentally sound techniques of animal and poultry manure processing. As a part of the ongoing work on implementation of best available techniques (BAT) in various sectors of Russian economy, agriculture included, the bioconversion technology of organic waste in a drum-type bio-fermenter was considered as one of BAT candidates, which is most adapted to the natural and climatic conditions of North-West Russia and feature the minimal environmental impact. The main purpose was to investigate the influence of bioconversion of solid fraction of cattle manure on selected microbial parameters and parasitic purity in the raw material, semi-finished and final products. The study was conducted in the IEEP Organic Waste Bioconversion Laboratory on a patented drum-type bio-fermenter. After 18 hours the digested material self-heated to 55 °C, i.e. the lower limit of the range of thermophilic microbial activity. By the 30th hour after the experiment started the temperature had reached the maximum level of 71 °C, then it dropped to 62–66 °C and stabilized in this range. 48 hours after the temperature reached 55 °C, the content of coliform bacteria reduced to acceptable limits, and that of Enterococcus dropped more than 10 times. After 120 hours the digested product was completely disinfected.

Key words:

biofermentation, cattle manure, disinfection, microbial parameters, parasitic purity