Timeframe of aerobic biodegradation of bioplastics differs under standard conditions and conditions simulating technological composting with biowaste.

To determine the actual timeframe of biodegradation, bioplastics (BPs) (based on polylactic acid (PLA), starch (FS), polybutylene succinate (PBS), cellulose (Cel)) were degraded with biowaste (B), which simulates real substrate technological conditions during composting. For comparison, standard conditions (with mature compost (C)) were also applied. The 90-day aerobic tests, both with C or B, were carried out at 58 ± 2 °C.

Assessment of biodegradability of cellulose and poly(butylene succinate)-based bioplastics under mesophilic and thermophilic anaerobic digestion with a view towards biorecycling.

Despite the increasing interest in bioplastics, there are still contradictory results on their actual biodegradability, which cause difficulties in choosing and developing appropriate sustainable treatment methods. Two biofoils (based on poly(butylene succinate) (PBS) and cellulose (Cel)) were anaerobically degraded during 100-day mesophilic (37 °C) and thermophilic (55 °C) tests (PBS, Cel). To overcome low degradation rates in mesophilic conditions, alkaline pre-treatment was also used (Pre-PBS, Pre-Cel).

Alginate-like polymers from full-scale aerobic granular sludge: content, recovery, characterization, and application for cadmium adsorption.

Aerobic granular sludge (AGS) is a proven resource for the recovery of biopolymers like alginate-like polymers (ALP). This is the first report on the dynamics of ALP produced by AGS (ALP-AGS) in a full-scale wastewater treatment plant (WWTP), optimization of ALP recovery from AGS, and adsorption of cadmium (Cd) by ALP. Recovery of ALP was highest when using 120 mL of 0.

Multi-faceted analysis of thermophilic anaerobic biodegradation of poly(lactic acid)-based material.

Currently, the production of bio-based polymeric materials, of which poly(lactic acid) (PLA) is the most popular, has been increasing, causing the growth of PLA waste in municipal waste. Thus, it is necessary to develop sustainable methods for treating it. Methane production, resulting from anaerobic digestion (AD), is a potential end-of-life scenario for PLA waste that needs to be investigated.

Plastic Waste Degradation in Landfill Conditions: The Problem with Microplastics, and Their Direct and Indirect Environmental Effects.

As landfilling is a common method for utilizing plastic waste at its end-of-life, it is important to present knowledge about the environmental and technical complications encountered during plastic disposal, and the formation and spread of microplastics (MPs) from landfills, to better understand the direct and indirect effects of MPs on pollution. Plastic waste around active and former landfills remains a source of MPs. The landfill output consists of leachate and gases created by combined biological, chemical, and physical processes.

Can the biological stage of a mechanical-biological treatment plant that is designed for mixed municipal solid waste be successfully utilized for effective composting of selectively collected biowaste?

Although the requirements for overall recycling rates can only be met when organic recycling is not overlooked, information is scarce regarding adaption to biowaste composting of existing mechanical-biological treatment (MBT) plants originally designed for stabilization of organic municipal solid waste (OFMSW). Thus, this study aimed to assess the suitability of the operational conditions in the biological part of a full-scale MBT plant now used for stabilization of OFMSW (working line: closed-module-covered-pile-open-pile) with a view to producing compost from biowaste. Temperatures above 75 °C were maintained in the closed module and reached again in the covered pile, indicating that intensive organic-matter mineralization occurred in both stages.

Valorization of full-scale waste aerobic granular sludge for biogas production and the characteristics of the digestate.

Despite the dynamic development of aerobic granular sludge (AGS) technology in wastewater treatment, there is limited data on how the different properties of AGS and activated sludge (AS) translate into differences in waste sludge management. Waste sludge generated in both AGS and AS technology is the biggest waste stream generated in wastewater treatment plants (WWTPs). This study aimed to assess biogas production from waste AGS from a full-scale system.

Strategies of Recovery and Organic Recycling Used in Textile Waste Management.

Post-consumer bio-based textile wastes are any type of garment or household article made from manufactured bio-based textiles that the owner no longer needs and decides to discard. According to the hierarchy of waste management, post-consumer textile waste should be organically recycled. However, there is still a problem with the implementation of selective collection of textile waste followed by sorting, which would prepare the waste for organic recycling.

Thermophilic and mesophilic biogas production from PLA-based materials: Possibilities and limitations.

Recently, the use of bio-based products, including biodegradable poly(lactic acid) (PLA), has increased, causing their rapid growth in municipal waste streams. The presence of PLA in biowaste may increase biogas production (BP). However, the rate of PLA biodegradation, which affects the time frame of anaerobic digestion, is a key parameter for an efficient process.

Insights into mechanisms of bisphenol A biodegradation in aerobic granular sludge.

Wastewater is the major source of bisphenol A (BPA) in the environment, however, the results regarding main mechanisms of BPA biodegradation in wastewater treatment systems are divergent. The effect of BPA concentration in wastewater (0, 2, 6, 12 mg BPA/L) on respirometric activity and expression of selected genes in aerobic granules was examined. A real-time protocol for analysis of direct BPA-degrader activity targeting gene coding for ferredoxin was developed.

Stabilisation of municipal solid waste after autoclaving in a passively aerated bioreactor.

Autoclaving of unsorted municipal solid waste is one of the solutions in waste management that maximises the amount of waste for recycling. After autoclaving, however, a large part of the waste is composed of unstabilised biodegradable fractions (organic remaining fraction, ORF), which may comprise up to 30% of autoclaved waste and cannot be landfilled without further stabilisation. Thus, the aim of this study was to investigate the effectiveness of aerobic stabilisation in a passively aerated reactor of organic remaining fraction after full-scale autoclaving of unsorted municipal solid waste.

Changes in extracellular polymeric substances (EPS) content and composition in aerobic granule size-fractions during reactor cycles at different organic loads.

This study aimed to systematically investigate the effect of organic loading on granule diameters, and on the composition of extracellular polymeric substances (EPS) in granules in various size-fractions at the beginning and end of the cycle of granular sludge sequencing batch reactor (GSBR). The organic loadings were 0.78 kg COD/(m·d) (GSBR1), 1.

Biological stability of multi-component agri-food digestates and post-digestates.

The use of digestate in agriculture has been an efficient way to mitigate greenhouse gas emissions through the recycling of organic materials. However, harmful effects can arise if the organic matter is unstable. The goal of this study was to determine the biological stability (4-day oxygen demand for degradation of readily biodegradable organic matter (AT4), 21-day anaerobic biogas potential (GP21), and organic matter (VS) content) of six digestates after mesophilic digestion, and that of the corresponding post-digestates after psychrophilic post-digestion.

Microbial structure and nitrogen compound conversions in aerobic granular sludge reactors with non-aeration phases and acetate pulse feeding.

A technological system was developed for efficient nitrogen removal from real digester supernatant in a single reactor with shortened aeration to increase the economical aspects of wastewater treatment. The supernatant (600 mg TKN/L, low COD/N ratio of 2.2) was treated in batch reactors with aerobic granules (GSBRs) to test how one, two, or three non-aeration phases and acetate pulse feeding in the cycle affect the morphological and microbial properties of biomass.

Nitrogen-converting communities in aerobic granules at different hydraulic retention times (HRTs) and operational modes.

This study determined how the activity and number of nitrogen-converting microorganisms varied with changes in hydraulic retention time (HRT) and the operating regime of aerobic granular sequencing batch reactors (GSBRs) treating high-nitrogen wastewater. Continuously aerated (O-mode) GSBRs were operated at HRTs of 10-, 13- and 19-h. Then the same reactors were operated at identical HRTs but the cycles started with an anoxic phase (A/O mode).

Removal of bisphenol A (BPA) in a nitrifying system with immobilized biomass.

The potential for bisphenol A (BPA) removal by mixed consortia of immobilized microorganisms with high nitrification activity was investigated with BPA concentrations in the influent from 2.5 to 10.0 mg/L.

Structure of nitrogen-converting communities induced by hydraulic retention time and COD/N ratio in constantly aerated granular sludge reactors treating digester supernatant.

This study investigated how hydraulic retention time (HRT) and COD/N ratio affect nitrogen-converting consortia in constantly aerated granules treating high-ammonium digester supernatant. Three HRTs (10, 13, 19 h) were tested at COD/N ratios of 4.5 and 2.

Cycle length and COD/N ratio determine properties of aerobic granules treating high-nitrogen wastewater.

Aerobic granule characteristic in sequencing batch reactors treating high-nitrogen digester supernatant was investigated at cycle lengths (t) of 6, 8 and 12 h with the COD/N ratios in the influent of 4.5 and 2.3.

Oxygen demand for the stabilization of the organic fraction of municipal solid waste in passively aerated bioreactors.

Conventional aerobic waste treatment technologies require the use of aeration devices that actively transport air through the stabilized waste mass, which greatly increases operating costs. In addition, improperly operated active aeration systems, may have the adverse effect of cooling the stabilized biomass. Because active aeration can be a limiting factor for the stabilization process, passive aeration can be equally effective and less expensive.

Treatment of high-ammonium anaerobic digester supernatant by aerobic granular sludge and ultrafiltration processes.

Anaerobic sludge digester supernatant characterized by 569 mg TKN L(-1), high color and a COD/N ratio of 1.4 was treated in granular sequencing batch reactors (GSBRs) followed by post-denitrification (P-D) and ultrafiltration (UF) steps. The use of granular sludge allowed for the oxidation of ammonium in anaerobic digester supernatant at all investigated GSBR cycle lengths of 6, 8 and 12 h.

Impact of operational parameters on bacterial community in a full-scale municipal wastewater treatment plant.

A bacterial community in activated sludge from a full-scale municipal wastewater treatment plant was monitored throughout the year with the use of FISH, RISA and DGGE techniques. In the investigated range of temperatures (11.9-21.

Changes in the ammonia-oxidizing bacteria community in response to operational parameters during the treatment of anaerobic sludge digester supernatant.

The understanding of the relationship between ammoniaoxidizing bacteria (AOB) communities in activated sludge and the operational treatment parameters supports the control of the treatment of ammonia-rich wastewater. The modifications of treatment parameters by alteration of the number and length of aerobic and anaerobic stages in the sequencing batch reactor (SBR) working cycle may influence the efficiency of ammonium oxidation and induce changes in the AOB community. Therefore, in the research, the impact of an SBR cycle mode with alternating aeration/ mixing conditions (7 h/1 h vs.

Nitrogen removal from wastewater and bacterial diversity in activated sludge at different COD/N ratios and dissolved oxygen concentrations.

The impact of the organic carbon to nitrogen ratio (chemical oxygen demand (COD)/N) in wastewater and dissolved oxygen (DO) concentration on carbon and nitrogen removal efficiency, and total bacteria and ammonia-oxidizing bacteria (AOB) communities in activated sludge in constantly aerated sequencing batch reactors (SBRs) was determined. At DO of 0.5 and 1.

Nitrogen removal from wastewater with a low COD/N ratio at a low oxygen concentration.

The goal of the study was to determine the effectiveness of nitrification and denitrification and the kinetics of ammonia removal from a mixture of wastewater and anaerobic sludge digester supernatant in an SBR at limited oxygen concentration. In addition, the COD removal efficiency and sludge production were assessed. In the SBR cycle alternating aerobic and anaerobic phases occurred; in the aeration phase the dissolved oxygen (DO) concentration was below 0.

The application of molecular techniques to the study of wastewater treatment systems.

Wastewater treatment systems tend to be engineered to select for a few functional microbial groups that may be organized in various spatial structures such as activated sludge flocs, biofilm or granules and represented by single coherent phylogenic groups such as ammonia-oxidizing bacteria (AOB) and polyphosphate-accumulating organisms (PAO). In order to monitor and control engineered microbial structure in wastewater treatment systems, it is necessary to understand the relationships between the microbial community structure and the process performance. This review focuses on bacterial communities in wastewater treatment processes, the quantity of microorganisms and structure of microbial consortia in wastewater treatment bioreactors.