Risk assessments for quality-assured, source-segregated composts and anaerobic digestates for a circular bioeconomy in the UK.

A circular economy relies on demonstrating the quality and environmental safety of wastes that are recovered and reused as products. Policy-level risk assessments, using generalised exposure scenarios, and informed by stakeholder communities have been used to appraise the acceptability of necessary changes to legislation, allowing wastes to be valued, reused and marketed. Through an extensive risk assessment exercise, summarised in this paper, we explore the burden of proof required to offer safety assurance to consumer and brand-sensitive food sectors in light of attempts to declassify, as wastes, quality-assured, source-segregated compost and anaerobic digestate products in the United Kingdom. We report the residual microbiological and chemical risks estimated for both products in land application scenarios and discuss these in the context of an emerging UK bioeconomy worth £52bn per annum. Using plausible worst case assumptions, as demanded by the quality food sector, risk estimates and hazard quotients were estimated to be low or negligible. For example, the human health risk of E. coli 0157 illness from exposure to microbial residuals in quality-assured composts, through a ready-to-eat vegetable consumption exposure route, was estimated at ~10-8 per person per annum. For anaerobic digestion residues, 7 × 10-3cases of E. coli 0157 were estimated per annum, a potential contribution of 0.0007% of total UK cases. Hazard quotients for potential chemical contaminants in both products were insufficient in magnitude to merit detailed quantitative risk assessments. Stakeholder engagement and expert review was also a substantive feature of this study. We conclude that quality-assured, source-segregated products applied to land, under UK quality protocols and waste processing standards, pose negligible risks to human, animal, environmental and crop receptors, providing that risk management controls set within the standards and protocols are adhered to.

Socioeconomic, agricultural, and individual factors influencing farmers' perceptions and willingness of compost production and use: an evidence from Wadi al-Far'a Watershed-Palestine.

In Palestine, open dumping and/or burning the waste, including agricultural waste, are prevalent practices resulting in emitting leachate and acidifying greenhouse gases. Composting the agricultural waste can reduce emissions and provide 'compost' as an organic fertilizer and soil amendment; yet, it has not been implemented at the national level. To develop a local marketing strategy for compost, this study views a need to identify farmers' perceptions and willingness of compost production and use in agriculture and examine various socioeconomic, agricultural, and individual factors shaping them. The case of Wadi al-Far'a watershed (WFW) is investigated, where farmers practice inappropriate waste disposal and overuse of agrochemicals. A semi-structured questionnaire is administered to 409 farmers through face-to-face interviews. Descriptive statistics, bivariate analyses, Chi-square test, and binary logistic regression are used for data analysis. High acceptance level (84%) is disclosed among farmers in WFW for the hypothetical idea of producing and using compost. Farmers also have high, yet lower, willingness level (63.6%) of the more salient option of producing compost themselves and using it in agriculture. Tenure systems, large cultivated areas, rainfed irrigation, and lack of access to training sessions inhibit farmers' acceptance of the idea of compost production (overall p value = 0.000). Large cultivated areas and rainfed irrigation is also associated with farmers' unwillingness to produce compost, besides high household monthly income, animal or mixed animal-plant farming, experience in compost production, and use of pesticides (overall p value = 0.000).

Adubação foliar e viabilidade econômica de potássio na cultura do trigo (triticum aestiavum l. ) / Foliar fertilization and economic feasibility of potassium in wheat (triticum aestiavum l. ) crops / Abono foliar y viabilidad económica de potasio en la cultura del trigo (triticum aestiavum l. )

A disponibilidade do nitrogênio (N) e do potássio (K) e a adequada proporção entre os dois são de grande importância para a realização de processos como crescimento e desenvolvimento das plantas. Este trabalho objetivou avaliar o efeito de fontes e doses de K em associação ao N em cobertura via foliar sobre as características produtivas do trigo (Triticum aestivum L.) cultivado em sistema de semeadura direta, em sucessão à cultura da soja. O experimento foi desenvolvido no ano de 2018 no município de Juranda, região centro oeste do Paraná. O delineamento experimental adotado foi o de blocos casualizados em esquema fatorial 5 x 1, com seis repetições, totalizando 30 parcelas experimentais, K e KN em combinação, em fase fenológicas diferentes, fase V5 (emborrachamento) e fase R7 (enchimento de grãos). Foram avaliados, tamanho de espiga, quantidade de grão por espiga, e peso de grão, para avaliar os reais benefícios da aplicação da adubação potássica via foliar. Para o número de espigas somente o tratamento com K em enchimento não diferiu do controle. No parâmetro número de grãos obteve-se os melhores resultados em K no emborrachamento e K e N no enchimento, entretanto, na massa de mil grãos o K no enchimento obteve a melhor média (40,75 g planta-1) em relação controle. Conclui-se que, a utilização do K via foliar aumenta o comprimento das espigas, número de grãos e massa de mil grãos e a aplicação do produto comercial K-40 no estádio de R7 aumenta em cerca de 30% a produtividade quando comparado ao controle.(AU)

The availability of nitrogen (N) and potassium (K) and the adequate ratio between the two are of great importance for processes such as growth and development of plants. The purpose of this paper was to evaluate the effect of sources and doses of K in association with N in foliar cover on wheat (Triticum aestivum L.) production grown under no-tillage system after soybean crop. The experiment was carried out in 2018 in the municipality of Juranda, central-western region of Paraná. The study used an experimental design in randomized blocks in a 5 x 1 factorial scheme, with 6 replicates, totaling 30 experimental plots, K and KN in combination, different phenological phases, V5 (rubberizing) and R7 (grain filling) phases. Ear size, grain per ear, and grain weight were assessed to evaluate the real benefits of foliar application of potassium fertilization. For the number of ears, treatment only with K during filling did not differ from the control; for number of grains per ear, the best results were obtained in K in the rubberizing, and K and N in the filling stages. However, for the weight of thousand grains, K in the filling stage presented the best mean (40.75 g plant-1) in the control ratio. It can be concluded that the use of K via foliar application increases the length of the ear, number of grains and weight per thousand grains. Application of the commercial product K-40 at the R7 stage increases yield by about 30%.(AU)

La disponibilidad del nitrógeno (N) y del potasio (K) y la adecuada proporción entre los dos son de gran importancia para la realización de procesos como crecimiento y desarrollo de las plantas. Este trabajo objetivó evaluar el efecto de fuentes y dosis de K en asociación al N en cobertura foliar sobre las características productivas del trigo (Triticum aestivum L.) cultivado en sistema de siembra directa, en sucesión al cultivo de la soja. El experimento se desarrolló en el año 2018 en el municipio de Juranda, región centro oeste de Paraná. El planteamiento experimental adoptado fue de bloques casualizados en esquema factorial 5 x 1, con seis repeticiones, totalizando 30 parcelas experimentales, K y KN en combinación, en fase fenológicas diferentes, fase V5 (encauchadas) y fase R7 (relleno de granos). Se evaluaron, tamaño de espiga, cantidad de grano por espiga, y peso de grano, para evaluar los reales beneficios de la aplicación de la fertilización potásica vía foliar. Para el número de espigas solamente el tratamiento con K en relleno no difirió del control. En el parámetro número de granos se obtuvo los mejores resultados en K en el encauche y K y N en el relleno, sin embargo, en la masa de mil granos el K en el relleno obtuvo la mejor media (40,75 g planta-1) en relación control. Se concluye que, la utilización del K vía foliar aumenta la longitud de las espigas, número de granos y masa de mil granos y la aplicación del producto comercial K-40 en la fase de R7 aumenta en un 30% la productividad mientras comparado al control.(AU)

Effects of aeration rates on the structural changes in humic substance during co-composting of digestates and chicken manure.

High humidity and potential threat of pathogen of anaerobic digestates are unfavorable to the environment by direct utilization. To achieve the sustainable utilization of digestates, composting might be a good choice. Meanwhile, the aeration rate of composting has been optimized. Co-composting of digestates and chicken manure was performed under different aeration conditions (0.05, 0.1 and 0.15 L·min-1·kg-1·organic matter (OM)). During composting, internal transformation of humic substance (HS) has been studied for obtaining the potential application value of the co-composting products. Results suggested that the HS concentration was increased by 21.1%, 26.4% and 22.4% with the aeration rates were 0.05, 0.1 and 0.15 L·min-1·kg-1·OM, respectively. The aeration rate of 0.15 L·min-1·kg-1·OM was more conducive to germination. Parallel factor analysis and dimensional correlation spectra (2DCOS) have been combined to reveal the conversion relationships of HS components for understanding the compost application pattern. Hetero-2DCOS indicated that aeration of 0.05 min-1·kg-1·OM and 0.1 L·min-1·kg-1·OM contributed to the formation of complex compounds at long wavelength, and aeration of 0.15 L·min-1·kg-1·OM was beneficial for labile compounds formation at short wavelength. In views of the aeration of 0.1 L·min-1·kg-1·OM was more beneficial to improve HS concentration than 0.05 L·min-1·kg-1·OM, 0.1 L·min-1·kg-1·OM and 0.15 L·min-1·kg-1·OM were consider as the most important aeration rate to conduct digestates composting. Overall, the aeration affected the HS composition which, in turn, might affect the application ways of composting products. This study could provide a reference for industrial composting production and applications.

Resource recovery of food waste through continuous thermophilic in-vessel composting.

In the Kingdom of Saudi Arabia (KSA) and Gulf region, a very small amount of municipal solid waste (MSW) is treated for compost production. The produced compost through traditional methods of compost piles and trenches does not coincide with the international standards of compost quality. Therefore, in this study, a continuous thermophilic composting (CTC) method is introduced as a novel and efficient technique for treating food waste into a quality compost in a short period of time. The quality of the compost was examined by degradation rates of organic matter (OM), changes in total carbon (TC), ash contents, pH, dynamics in ammonium nitrogen (NH4-N) and nitrate nitrogen (NO3-N), and nitrification index (NI). The results showed that thermophilic treatment at 60 °C increased the pH of the substrate and promoted degradation and mineralization process. After 30 days of composting, the degree of OM degradation was increased by 43.26 and 19.66%, NH4-N by 65.22 and 25.23%, and NO3-N by 44.76 and 40.05% as compared to runs treated at 25 and 40 °C, respectively. The stability of the compost was attained after 30 to 45 days with quality better than the compost that was stabilized after 60 days of the experiment under mesophilic treatment (25 °C). The final compost also showed stability at room temperature, confirming the rapid degradation and maturation of food waste after thermophilic treatment. Moreover, the quality of produced compost is in line with the compost quality standard of United States (US), California, Germany, and Austria. Hence, CTC can be implemented as a novel method for rapid decomposition of food waste into a stable organic fertilizer in the given hot climatic conditions of KSA and other Gulf countries with a total net saving of around US $70.72 million per year.

Obsolete Laws: Economic and Moral Aspects, Case Study-Composting Standards.

From the early days of philosophy, ethics and justice, there is wide consensus that the constancy of the laws establishes the legal system. On the other hand, the rate at which we accumulate knowledge is gaining speed like never before. Due to the recently increased attention of academics to climate change and other environmental issues, a lot of new knowledge has been obtained about carbon management, its role in nature and mechanisms regarding the formation and degradation of organic matter. A multidisciplinary techno-economic assessment of current composting standards and laws that took into account the current state of knowledge about carbon management was carried out as a case study. Economic and environmental damage caused by outdated laws was revealed. In addition, it was found that the introduction of the best composts into the market is permitted, causing additional negative environmental as well as economic impacts.