Application of the Sewage Sludge in Agriculture: Soil Fertility, Technoeconomic, and Life-Cycle Assessment

Disposal of sewage sludge, which is a by-product of wastewater treatment, has become one of the greatest challenges of the twenty-first century. Conversion of sewage sludge to a soil amendment can be performed by a broad spectrum of methods, which greatly differ by substrate/amendment composition, treatment time, and physicochemical conditions. The book chapter is focused on (i) environmental and legislative aspects of sewage sludge application in agriculture; (ii) risk factors related to the abundance of pathogens in sewage sludge and methods of SS hygienization; (iii) optimization of the use of SS-derived fertilizers. Application of sewage sludge in combination with mineral fertilizers positively influenced crop growth and soil microbiological activity. An environmental impact of sewage sludge related to its disposal to agricultural areas has been analyzed in terms of global warming, ecotoxicity, and other internationally recognized issues. Narrowly targeted measures may aggravate the situation. Some site-specific factors make sewage sludge unique, hence this specificity must be considered to predict the outcome of its treatment. Determination of these factors remains challenging. Therefore, the complexity of sewage sludge can be reduced by employing integrated biorefinery approaches that will result in circular bioeconomy and industrial ecology solutions

Microbial community changes in TNT spiked soil bioremediation trial using biostimulation, phytoremediation and bioaugmentation

Trinitrotoluene (TNT), a commonly used explosive for military and industrial applications, can cause serious environmental pollution. 28-day laboratory pot experiment was carried out applying bioaugmentation using laboratory selected bacterial strains as inoculum, biostimulation with molasses and cabbage leaf extract, and phytoremediation using rye and blue fenugreek to study the effect of these treatments on TNT removal and changes in soil microbial community responsible for contaminant degradation. Chemical analyses revealed significant decreases in TNT concentrations, including reduction of some of the TNT to its amino derivates during the 28-day tests. The combination of bioaugmentation-biostimulation approach coupled with rye cultivation had the most profound effect on TNT degradation. Although plants enhanced the total microbial community abundance, blue fenugreek cultivation did not significantly affect the TNT degradation rate. The results from molecular analyses suggested the survival and elevation of the introduced bacterial strains throughout the experiment. First published online: 15 Feb 201

Current Trends in Bioaugmentation Tools for Bioremediation: A Critical Review of Advances and Knowledge Gaps

Bioaugmentation is widely used in soil bioremediation, wastewater treatment, and air biofiltration. The addition of microbial biomass to contaminated areas can considerably improve their biodegradation performance. Nevertheless, analyses of large data sets on the topic available in literature do not provide a comprehensive view of the mechanisms responsible for inoculum-assisted stimulation. On the one hand, there is no universal mechanism of bioaugmentation for a broad spectrum of environmental conditions, contaminants, and technology operation concepts. On the other hand, further analyses of bioaugmentation outcomes under laboratory conditions and in the field will strengthen the theoretical basis for a better prediction of bioremediation processes under certain conditions. This review focuses on the following aspects: (i) choosing the source of microorganisms and the isolation procedure; (ii) preparation of the inoculum, e.g., cultivation of single strains or consortia, adaptation; (iii) application of immobilised cells; (iv) application schemes for soil, water bodies, bioreactors, and hydroponics; and (v) microbial succession and biodiversity. Reviews of recent scientific papers dating mostly from 2022–2023, as well as our own long-term studies, are provided here

Raugi un smagie metali: dazi fiziologijas un teoretiskas biotehnologijas aspekti

Abstract in Latvian, English, RussianAvailable from Latvian Academic Library / LAL - Latvian Academic LibrarySIGLELVLatvi

Latvijas mālu pielietošana biotehnoloģijā: rezultāti un perspektīvas

Mūsu pētījumi ir saistīti ar Latvijas māliem unno tiem iegūtām šūnainās keramikas granulām. Pētījumi parkeramikas nesējmateriālu izveidi sastāv no trim apakšvirzieniem:1) izejmateriāla testēšana un keramikas nesējmateriāluizgatavošanas tehnoloģijas izstrāde; 2) bioplēves veidošanās uzkeramikas granulām: dinamika un noturība; 3) vides attīrīšanasmodeļu eksperimenti. Šajā rakstā ir apkopoti galvenie rezultātipar laika periodu no 2010. līdz 2013. gadam, kā arī ieskicētiperspektīvi virzieni turpmākai pētīšana

Antimicrobial Properties of the Modified Cotton Textiles by the Sol-Gel Technology

Comparison of the antimicrobial properties of textiles with amorphous coatings containing Zn and Si obtained by the sol-gel technology against microorganisms Pseudomonas fluorescens, Saccharomyces cerevisiae, Trichoderma viride that can cause cotton textile destruction was made. Modified textiles were evaluated using scanning electron microscopy, energy dispersive x-ray spectroscopy. Investigation of antimicrobial properties of the cotton fabric samples treated with different zinc acetate dihydrate concentration sols and various thermal post-treatments was made. Strong inhibition of microbial growth was detected for all cotton textile samples treated via sol-gel method according all tests microorganisms

Biodegradation of Oil Sorbed on Peat after its Use as a Spill Cleanup Sorbent

Thermally treated peat is known to be a prospective sorbent for oil removal. The used oil spill clean-up sorbents could be further reused for a few cycles, if an appropriate treatment is undertaken. In this study, a 36 days biodegradation batch experiment was performed with oil-degrading bacteria consortium MDK.EKO-7 and a peat sorbent (PeatOS) contaminated with diesel or raw oil. FDA hydrolysis, urease and dehydrogenase activity, as well as the concentration of hydrocarbons were measured in a peat-slurry system. Biodegradation of hydrocarbons up to 90 % was detected in the set with 2% (w/w) diesel-oil contaminated peat. The measured enzymes behaved differently over time. The peat sorbent (PeatOS) contaminated by raw oil with concentration 5mg/g dw, inhibited growth of bacteria consortium. Addition of nitrogen and plant extract to a peat-slurry with 2% diesel resulted in a significant (p<0.05) increase of FDA hydrolysis and urease activity after 36 days' incubation. The results obtained in this study, indicate that a recovery of the used oil-spilled peat sorbent is possible. Further experiments will be performed in order to optimise biodegradation conditions, using nutrients and surfactants