Petroleum contains carcinogens and toxic substances that can have an unfavorable impact on environmental quality and human health when the soil becomes contaminated with crude oil.  BBiostimulation and bioaugmentation are the main strategies in the bioremediation of oil-contaminated soils. To decompose old-aged petroleum pollution in saline soil, a full factorial experiment was utilized. The experiment was designed using a completely randomized design with four factors: bacterial inoculum, sugarcane bagasse, chemical fertilizer, and molasses. The application of these factors was conducted in four separate experiments: pretreatment of agricultural soil and spent mushroom compost, pretreatment of spent mushroom compost, pretreatment of agricultural soil, and no pretreatment. After a 60-day incubation period at 28 ˚C, the results showed that the organic wastes of molasses and spent mushroom compost in combination with bacterial inoculum reduced total petroleum hydrocarbons 38 and 33.3%, respectively. Molasses had a considerable impact on increasing the efficiency of bacterial inoculum 1 and bacterial inoculum 3. Similarly, spent mushroom compost was found to significantly affect bacterial inoculum 1. In addition, bagasse was observed to accelerate the bioremediation process by improving the physical conditions of the soil. In the pretreatment of agricultural soil, bagasse in combination with bacterial inoculum 1 and chemical fertilizer reduced the total petroleum hydrocarbons significantly (38%) compared to the control treatment. These results highlight the effectiveness of organic wastes as biostimulation agents in promoting the growth and reproduction of the soil microbial community, as well as establishing the bacterial inoculum.

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In recent years, pollution of antibiotics and heavy metal has often been reported in organic wastes. Saprophytic insects have been recorded as biological control agents in organic waste management. During organic waste conversion, the intestinal bacteria of the saprophytic insects play an important role in digestion, physiology, immunity and prevention of pathogen colonization. Black soldier fly (BSF) Hermetia illucens has been widely used as saprophytic insects and showed tolerance to sulfonamides (SAs) and cadmium (Cd). Diversity and changes in gut microbiota of black soldier fly larvae (BSFL) were evaluated through 16S rRNA high-throughput sequencing, and a decrease in diversity of gut microbiota along with an increase in SAs stress was recorded. Major members identified were Actinomycetaceae, Enterobacteriaceae, and Enterococcaceae. And fourteen multi-resistance Klebsiella pneumoniae strains were isolated. Two strains BSFL7-B-5 (from middle midgut of 7-day BSFL) and BSFL11-C-1 (from posterior midgut of 11-day BSFL) were found to be low-toxic and multi-resistance. The adsorption rate of SAs in 5 mg/kg solutions by these two strains reached 65.2% and 61.6%, respectively. Adsorption rate of Cd in 20 mg/L solutions was 77.2% for BSFL7-B-5. The strain BSFL11-C-1 showed higher than 70% adsorption rates of Cd in 20, 30 and 40 mg/L solutions. This study revealed that the presence of multi-resistance bacterial strains in the gut of BSFL helped the larvae against SAs or Cd stress. After determining how and where they are used, selected BSFL gut bacterial strains might be utilized in managing SAs or Cd contamination at suitable concentrations in the future.

Composting is a solid waste management alternative that avoids the emission of methane associated with its disposal in landfill and reduces or eliminates the need for chemical fertilisers if compost is applied. The main objective of this study was to analyse the environmental burdens of composting as a way to achieve a more circular valorisation of wine waste. To do so, with the purpose of identifying optimal operational conditions and determining the “hotspots” of the process, the life cycle assessment (LCA) methodology was used. The consumption of diesel fuel in machinery was determined to be the main critical point in the environmental effects of the system, followed by the transport and distribution of the compost. After the application of compost instead of mineral fertilisers, corn, tomato and strawberry crops would have a better environmental performance in most impact categories. In this sense, a maximum improvement of 65% in terrestrial ecotoxicity is achieved in strawberry cultivation. In light of the results obtained, it is demonstrated that composting is a suitable way of organic waste valorisation according to Circular Economy principles.

Acceleration of urbanization and industrialization has resulted in the drastic rise of waste generation with majority of them being biowaste. This constitutes a global challenge since conventional waste management methods (i.e., landfills) present environmental issues including greenhouse gases emissions, leachate formation and toxins release. A sustainable and effective approach to treat biowaste is through composting. Various aspects of composting such as compost quality, composting systems and compost pelletization are summarized in this paper. Common application of compost as fertilizer or soil amendment is presented with focus on the low adoption level of organic waste compost in reality. Rarely known, compost which is easily combustible can be utilized to generate electricity. With the analysis on critical approaches, this review aims to provide a comprehensive study on energy content of compost pellets, which has never been reviewed before. Environmental impacts and future prospects are also highlighted to provide further insights on application of this technology to close the loop of circular bioeconomy.

Copper (Cu) is known to accumulate in agricultural soils receiving urban waste products as fertilizers. We here report the use of the leucine incorporation technique to determine pollution-induced community tolerance (Leu-PICT) to Cu in a long-term agricultural field trial. A significantly increased bacterial community tolerance to Cu was observed for soils amended with organic waste fertilizers and was positively correlated with total soil Cu. However, metal speciation and whole-cell bacterial biosensor analysis demonstrated that the observed PICT responses could be explained entirely by Cu speciation and bioavailability artifacts during Leu-PICT detection. Hence, the agricultural application of urban wastes (sewage sludge or composted municipal waste) simulating more than 100 years of use did not result in sufficient accumulation of Cu to select for Cu resistance. Our findings also have implications for previously published PICT field studies and demonstrate that stringent PICT detection criteria are needed for field identification of specific toxicants.

A large amount of plastic waste has been discharged into the environment worldwide, which causes the current white pollution problem. The accumulated waste plastics in the environment can be furtherly degraded into small pieces such microplastics and nanoplastics through weathering, which will do more harm to the environment and humans than large plastics. Therefore, plastic production and disposal are needed to be considered. Biodegradable plastics (BPs) have become the focus of recent research due to their potential biodegradability and harmlessness, which would be the most effective approach to manage the issue of plastic waste environmental accumulation. However, in the long run, it is uncertain whether BPs can be a promising solution to waste disposal and global plastic pollution. Consequently, both sides of the dispute are discussed in this paper. At present, most conventional plastics can not be replaced by theses BPs. Biodegradation of BPs needs certain environmental conditions, which are not always reliable in the environment. Additionally, changes in human behavioral awareness will also affect the development and application of BPs. BPs should not be considered as a technical solution, thus excusing our environmental responsibility, because littering does not change with the promotion of an effective technology. As such, the conclusion is that BPs may be a part of the solution. The effectiveness in providing environmentally solutions for plastic waste management depends on the combination of affordable waste classification technologies and investment in organic waste treatment facilities. Therefore, there is still a long way to go to solve the global plastic pollution through BPs.

In this study, effects of sewage sludge and manure borne dissolved organic carbon (DOC) on 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) sorption and mineralization processes were investigated in three agricultural soils. Batch equilibrium techniques and equilibrium dialysis methods were used to determine sorption mechanisms between DOC, estrogens and the soil solid phase. It was found that that the presence of organic waste borne DOC decreased estrogen sorption in soils which seems to be controlled by DOC/estrogen complexes in solution and by exchange processes between organic waste derived and soil borne DOC. Incubation studies performed with 14C-estrogens showed that DOC addition decreased estrogen mineralization, probably due to reduced bioavailability of estrogens associated with DOC. This increased persistence combined with higher mobility could increase the risk of estrogen transport to ground and surface waters. The effect of DOC on estrogen sorption and mineralization is influenced by exchange processes between organic waste borne and soil derived DOC.

Organic matter from salmon farms has been shown to be assimilated by soft sediment and rocky reef communities within the ecological footprint of salmon farms. Given these findings, another question arises – What other chemicals in salmon feed may be assimilated into wild communities via organic waste from salmon farms? Here we measured a suite of organic contaminants in salmon feed, in organisms used in a controlled feeding experiment, and in reef species collected within the depositional footprint of salmon farms. Gas Chromatography-Tandem Mass Spectrometry was used to quantify trace concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and current-use (CPUs) and historic-use pesticides (HUPs) in salmon feed imported to New Zealand. The effect of assimilation of farm-derived organic matter on contaminant profiles differed among species during the controlled feeding experiment and demonstrated that migration of individuals to a farm-associated site has the potential to increase or decrease organic contaminant concentrations. Concentrations of PCBs in Parapercis colias (blue cod), a highly resident, long-lived fish, were significantly higher at farm sites than at reference sites. While these concentrations were relatively low in a global context, this result presents blue cod as an important candidate for future monitoring of organic contaminants around point sources. PCBs and PBDEs measured in wild marine species were all below limits set by the European Union, whereas concentrations of certain HUPs, specifically dichlorodiphenyltrichloroethane (DDT) and its degradation products and endosulfan, may be of concern as a consequence of alternative anthropogenic activities. Overall, feed imported to New Zealand had relatively low levels of most organic contaminants that, at current levels, are unlikely to result in significant ecological effects to wild communities in adjacent habitats.

The arsenic concentration is an important issue in compost production. The main inputs of a compost factory, including kerbsides, green wastes, food industry wastes, and river weeds are investigated in this study. Also, this study investigated how treated timbers, ashes, and other contamination can impact arsenic concentration in compost production. The results showed that most treated timbers and all ashes of treated and untreated timbers contained significant amounts of arsenic. These results revealed that the presence of a small amount of treated timber ashes can significantly increase the arsenic concentration in composts. The results of the study show the arsenic concentration in compost increase during cold months, and it dropped during summer, which would be mostly because of high arsenic concentration in ashes of log burners. This study shows ashes of burning timbers can impact arsenic contamination mostly because of using Copper-Chrome-Arsenic wood preservatives (CCA). Also, the lab results show the arsenic level even in ashes of untreated timber is around 96 ppm. The ashes of H3, H4, and H5 treated timbers contain approximately 133,000, 155,000, and 179,000 ppm of arsenic, which one kg of them can increase arsenic concentration around 10 ppm in 13.3, 15.5 and 17.9 tons of dry compost products. The main problem is many people look at ashes and treated timber as organic materials; however, ashes of treated and untreated timbers contained high concentrations of arsenic. Therefore, it was necessary to warn people about the dangers of putting any ashes in organic waste bins.