Adsorption of acetamiprid, chlorantraniliprole and flubendiamide on different type of microplastics present in alluvial soil.

The presence of microplastics (MPs) and their effects have been widely investigated in the aquatic environment, whereas the research done in the terrestrial environment is incomparably lacking. MPs are considered a pollutant in soil on agricultural land, where they can act as a vector for other pollutants, namely organic chemical compounds, such as pesticides. In soil, presence of MPs is affecting the growth and life of microorganisms in it. The interactions between two types of MPs and three pesticides in the mixture with alluvial soil were studied. Adsorption of acetamiprid, chlorantraniliprole and flubendiamide in concentrations of 1, 5 and 10 mg L-1 onto polyester fibres and polypropylene particles of 0.5-1 mm size was studied at 1% and 5% (w/w) of their content in soil. Results showed that the adsorption of pesticides was dependent on their octanol/water partition coefficient, with the most highly adsorbed pesticide also being the most hydrophobic, regardless of the type and form of MPs. Adsorption of pesticides onto MP particles was confirmed in soil-MPs mixtures with 5% polypropylene and 5% polyester at all tested pesticides' concentrations, proving that MPs in soil systems act as carriers to pollutants. MPs in soil decreased the soil's intrinsic capacity to retain pesticides, indicating the possibility of a greater mobility of pesticides on MPs through the soil system.

Faecal indicator bacteria and antibiotic-resistant ß-lactamase producing Escherichia coli in blackwater: a pilot study.

The aim of this study was to identify and quantify faecal indicator bacteria in blackwater collected from a source separation unit and determine the amount of E. coli isolates resistant to antimicrobials and their potential to produce extended spectrum ß-lactamases (ESßLs) and metallo-ß-lactamases (MßLs), which hydrolyse the most important antibiotics used in clinical practice. Most of the isolates were resistant to amoxicillin with clavulanic acid (36.4 %), followed by ticarcillin with clavulanic acid (22.7 %) and tetracycline (18.2 %). ESßL-producing genes blaCTX-M and blaTEM were found in three (13.6 %) and four (18.2 %) E. coli strains, respectively, while MßL genes were found in two (9.1 %). By separating at source, this pilot study clearly shows that gastrointestinal bacteria of healthy people can be an important source of antibiotic resistance released into the environment through wastewaters. One way to prevent that is to treat wastewater with a combination of TiO2, UV light, or ozone, as successful methods to remove resistant bacteria and prevent their spread in the environment.

A comparison of various bulking materials as a supporting matrix in composting blackwater solids from vacuum toilets.

This study discusses the influence of six bulking materials (peat, bark, oat husks, sawdust, food waste, and wheat bran) on the composting of blackwater solids (feces, urine and toilet paper) from low flush vacuum toilets (0.8 L/flush). The focus was on faecal indicator reduction, nutrient recycling, and carbon dioxide and methane emissions. In a composting experiment lasting 60 days, bulking materials were combined and mixed with blackwater solids, composted without stirring and with controlled aeration in a bench scale experiment. The bulking materials combination of oat husks, wheat bran and bark and of oat husks and wheat bran composted with blackwater solids showed the best results in terms of faecal indicator reduction (2.8 log10 reduction of Escherichia coli and 3.2 log10 reduction of faecal streptococci, respectively). Oat husks, bark and wheat bran combination had the smallest nutrient losses of 7.5% total nitrogen, 3.8% total phosphorus and 28% total potassium, while the highest accumulation in total phosphorus was 76.4% occurred in the mixture with oat husks and wheat bran. Peat and food waste improved the sorption of ammonia. The highest methane emissions (average 15.4%) were detected after 28 days of composting in the mixture with bran and food waste. Methane and carbon dioxide levels decreased in all the mixtures towards the end of composting indicating high organic matter degradation. Our findings show that a variety of natural and inexpensive materials can be used and adapted when composing blackwater in remote and sensitive areas.

Removal of particles in organic filters in experimental treatment systems for domestic wastewater and black water.

This study assesses the total suspended solids (TSS) retention capacity of different organic filter media for two potential applications: (i) a polishing unit for package treatment plants and (ii) a pretreatment for blackwater from low-flushing toilets. The results showed that the peat filter media used can be significantly improved in terms of structural stability and TSS removal capacity by mixing it with sawdust. Most of the TSS accumulated in the upper part of the filter material, and filter thickness exceeding 15 cm had no statistically significant effect (P < 0.1) on the TSS treatment performance. The experimental system reached a TSS reduction of 60-70% for blackwater and 80-90% for simulated effluent peaks from a package treatment plant. The main challenge of a full-scale application of an organic filter is the issue of clogging, especially when treating concentrated blackwater. However, this work indicates that a clogged filter media can be regenerated by mixing the uppermost filter layer without significant loss of filter performance regarding TSS. More research is needed to develop an appropriate mechanical unit for automatic filter media regeneration.