Evaluation of contamination levels of different types of composts and their suitability for usage in agriculture

Abstract

The aim of the study was to investigate the composition of different organic substances and the amount of nutrients in composts produced from green waste, food waste, sewage sludge, cattle manure and digestate as well as to assess the contamination with persistent organic pollutants and heavy metals. Composts produced in 2015 and 2016 in different regions of Lithuania and in different weather conditions were used for the research. Chemical analyses of composts were done according to the international standards and requirements for soil improvement substances. Of all the composts tested, green waste compost had the lowest content of organic matter, nitrogen and phosphorus. The results of the experiment suggest that digestate, which was characterised by the highest organic matter content, contained the smallest quantity of fulvic and humic acids that are of key importance to the recovery of soil organic content. It was established that sewage sludge composts were the most contaminated with heavy metals and polychlorbiphenyls; the content of the analysed polychlorbiphenyls totalled 37.8 µg kg-1 in the samples of the year 2015 and 29.4 µg kg-1 in the samples of 2016. The lowest content of heavy metals and polychlorbiphenyls was recorded in cattle manure and food waste composts. No polychlorbiphenyls were found in the samples of 2015. The findings suggest that sewage sludge compost is the least suitable for being used in agriculture, because of its pollution with heavy metals and persistent organic pollutants. Green waste compost only increased the quantity of organic matter, while compost from cattle manure, food waste and digestate not only improved the soil structure, but significantly increased nutrients concentration.

Effect of biochar addition method on ammonia volatilization and quality of chicken manure compost

“…Recently, the recycling of animal waste and post-harvest materials has been received economic and environmental attention (Sarkar et al, 2016). Composting is a useful technology based on biochemical conversion of agricultural waste into the humified organic matter under aerobic conditions (Višniauskė et al, 2018;Ayilara et al, 2020). It can also reduce the mass and volume of the waste, destroy the pathogens and weed seeds and provide organic fertilizer for sustainable agriculture (Luo et al, 2014).…”

Gas chromatographic analysis of polychlorinated biphenyls in compost samples from different origin

“…According to Bucheli and Brändli (2006), there are four important processes that influence PCBs levels during composting: evaporation, sequestration, transformation and contamination during sample preparation. Other scientists, who also investigated composts and composting processes, determined that the level of contamination depends on compost-making technology (Koolivand et al, 2018; Višniauskė et al, 2018). Influence of the technological process of making compost is expressed on the qualitative and quantitative results (Koolivand et al, 2017).…”

“…In accordance with the hygienic norm (HN 60:2004), which describes the maximum permissible concentrations of dangerous chemical substances in the soil, 100 µg kg −1 of PCBs can be permitted. According to the quality requirements for composts used in agriculture (Višniauskė et al, 2018), it is recommended that the total content of polychlorinated biphenyls does not exceed 400 µg kg −1 in dry matter. All investigated composts satisfied this requirement, except for 14% of investigated mixed municipal waste composts, total PCBs levels were higher than 400 µg kg −1 .…”

A Mixture of Green Waste Compost and Biomass Combustion Ash for Recycled Nutrient Delivery to Soil

“…Atomic Absorption Spectroscopy (AAS) (Thermo Fisher Scientific, Waltham, MA, USA) was used to measure the concentration of total calcium Ca and total magnesium Mg; a flame photometer (FP) (Sherwood, Cambridge, UK) for total potassium K; a UV-VIS spectrophotometer (Shimadzu, Duisburg, Germany) for total phosphorus P; and inductively coupled plasma mass spectrometry (ICP-MS) (Thermo Fisher Scientific, Waltham, MA, USA) for the heavy metals (Cu, Cd, Cr, Ni, Pb, and Zn) [14]. Total nitrogen (N tot ) was determined using the Kjeldahl nitrogen distiller method while organic carbon (C org ) was determined using a dry combustion method with a total carbon analyzer Liqui TOC II [15].…”