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In this research, the application of home composting system as an alternative approach for household organic waste management was investigated. A rotary drum home composter made of galvanized steel was designed and used for the composting process. It consists of two chambers of about 170 L each, and is equipped with sufficient holes to ensure aerobic conditions as well as valves for leachate drainage. Different parameters, including using waste to bulking agent ratio, co-composting using animal manure and introducing charcoal with the feedstock were investigated. The designed reactor proved its efficiency for composting purposes, according to the obtained results regarding the degradation of the organic waste with ease operation and monitoring. The highest reduction volume (85%) in the composted materials was in treatment of 1:0.5 waste to bulking agent, whereas co-composting using animal manure better enhanced the organic matter degradation, as the highest decrease in the C/N ratio (about 62%) was observed in this treatment. No significant effect of the charcoal war recorded regarding the degradation process, but was clear in reducing odors. [ABSTRACT FROM AUTHOR]

In this study, a survey was conducted to determine the public opinion regarding the acceptance of using home composters as an alternative approach for household organic waste management. This approach is introduced as a method to replace the landfilling of organic municipal solid waste, which is the main solid waste management currently employed in Palestine, considering Anabta town as a case study. The results showed that people in the target area are welcoming of the home composting idea, and about 99% of participants are interested in owning home composters at their properties, which is regarded as a good reference for implementing the proposed home composting scheme in this area. The results showed that people are interested in the new proposed scheme for organic household waste despite their minimal knowledge and understanding about the composting process's importance and effects. The survey tested the people's expectations and thoughts about the home composting concept and found that the main motives for home composting were reducing the cost of house gardening and using the produced compost in soil nutrition, besides being part of environmental sustainability. On the other side, obstacles were due to people's inexperience of the home composting method, as almost half of participants were expecting an exhausting, long process to produce compost, with the related bad smell and insects during composting progression. Hence, the study found that it is important to spread awareness about the right procedures to apply home composting among participants, in line with environmental awareness campaigns through social media, and provide personalized follow-up with participants. [ABSTRACT FROM AUTHOR]

Real field demonstrations to assess the removal efficiency of nutrients and organic matter from domestic wastewater were carried out using algal-bacterial photobioreactors. The reactors which consisted of three basins of 200 L were fed with secondary effluent of domestic wastewater and operated under natural day light/dark cycles. The results demonstrated that reaction time (RT) has a substantial role on the whole process performance. Whereas inoculation with nitrifiers affected the process only in some aspects. The enhancement in the dissolved oxygen production rate (1.15 mg O 2. L−1.h−1) was in alignment with growing higher algal biomass concentrations due to the increase in RT. COD removal rates were significantly increased (p < 0.05) with increasing the RT, and removal rates of 27%, 46% and 50% were obtained under RTs of 2, 3 and 4hrs. respectively. Meanwhile, 30%, 84% and 95% of the phosphorus was removed under the same studied RTs. No significant effect was recorded due to the addition of nitrifying bacteria on the removal of both COD and phosphorus. Ammonium (NH 4 +-N) removal rates were also increased with increasing RT and by the addition of nitrifiers, such that removal rates of 13%, 21% and 31% were obtained in basins inoculated with nitrifiers, but 11%, 14% and 19.5% were obtained in non-inoculated basins under RT of 2, 3, and 4 hrs. respectively. These results provide some new insights into algal-bacterial symbiosis systems under real field conditions which could be helpful for further process development. [ABSTRACT FROM AUTHOR]

Bioremediation of contaminated soils has gained increasing interest in recent years as a low-cost and environmentally friendly technology to clean soils polluted with anthropogenic contaminants. However, some organic pollutants in soil have a low biodegradability or are not bioavailable, which hampers the use of bioremediation for their removal. This is the case of polycyclic aromatic hydrocarbons (PAHs), which normally are stable and hydrophobic chemical structures. In this review, several approaches for the decontamination of PAH-polluted soil are presented and discussed in detail. The use of compost as biostimulation- and bioaugmentation-coupled technologies are described in detail, and some parameters, such as the stability of compost, deserve special attention to obtain better results. Composting as an ex situ technology, with the use of some specific products like surfactants, is also discussed. In summary, the use of compost and composting are promising technologies (in all the approaches presented) for the bioremediation of PAH-contaminated soils. [ABSTRACT FROM AUTHOR]

Anaerobic digestion (AD) has become extremely popular in the last years to treat and valorize organic wastes both at laboratory and industrial scales, for a wide range of highly produced organic wastes: municipal wastes, wastewater sludge, manure, agrowastes, food industry residuals, etc. Although the principles of AD are well known, it is very important to highlight that knowing the biochemical composition of waste is crucial in order to know its anaerobic biodegradability, which makes an AD process economically feasible. In this paper, we review the main principles of AD, moving to the specific features of lignocellulosic wastes, especially regarding the pretreatments that can enhance the biogas production of such wastes. The main point to consider is that lignocellulosic wastes are present in any organic wastes, and sometimes are the major fraction. Therefore, improving their AD could cause a boost in the development in this technology. The conclusions are that there is no unique strategy to improve the anaerobic biodegradability of lignocellulosic wastes, but pretreatments and codigestion both have an important role on this issue. [ABSTRACT FROM AUTHOR]

The degradation of polycyclic aromatic hydrocarbons (PAHs) including fluorene, phenanthrene, anthracene, fluoranthene and pyrene were investigated under thermophilic and mesophilic anaerobic-methanogenic conditions. By using central composite design, the impact of PAH concentration and soil to inocula ratio were systematically studied for their influence on PAH removal and biogas production. During the first 30 days, PAH concentration decreased in all samples indicating that the inocula used were able to biodegrade the contaminants; although an inhibition effect was initially observed in biogas production. Phospholipids fatty acids analysis was used to monitor the microbial communities present during the process. These communities were more complex in samples containing moderate to high PAH contamination concentrations. After 50 days, the concentration of PAHs increased in the majority of samples indicating possible reversed biotransformation of these compounds. [ABSTRACT FROM AUTHOR]

Abstract: The degradation of several polycyclic aromatic hydrocarbons (PAHs) in soil through composting was investigated. The selected PAHs included: fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, and chrysene, with concentrations simulating a real creosote sample. The degradation of PAHs (initial concentration 1 g of total PAHs kg−1 dry soil) was assessed applying bioaugmentation with the white-rot fungi Trametes versicolor and biostimulation using compost of the source-selected organic fraction of municipal solid waste (OFMSW) and rabbit food as organic co-substrates. The process performance during 30 days of incubation was evaluated through different analyses including: dynamic respiration index (DRI), cumulative oxygen consumption during 5 days (AT5), enzymatic activity, and fungal biomass. These analyses demonstrated that the introduced T. versicolor did not significantly enhance the degradation of PAHs. However, biostimulation was able to improve the PAHs degradation: 89% of the total PAHs were degraded by the end of the composting period (30 days) compared to the only 29.5% that was achieved by the soil indigenous microorganisms without any co-substrate (control, not amended). Indeed, the results showed that stable compost from the OFMSW has a greater potential to enhance the degradation of PAHs compared to non-stable co-substrates such as rabbit food. [Copyright &y& Elsevier]

Abstract: In this study, the bioremediation of polycyclic aromatic hydrocarbons (PAHs)-contaminated soil under strict anaerobic-methanogenic conditions was systematically studied applying the central composite design approach. The effect of PAHs concentration and the stability of the compost as an organic amendment for anaerobic digestion were examined. In all assays, the used methanogenic consortium was able to degrade the PAHs although some inhibition effects were observed during the initial stage in some cases. The degradation rates varied between 31.4 and 90.6% during 50 days incubation period. The study demonstrated that the PAHs concentration influences the degradation rate where more degradation was observed by increasing the concentration of PAHs. However, the biogas production as a result of the digestion process was more influenced by the compost stability which also has its effect on the degradation rates as more degradation occurred with more stable compost, but more biogas was produced with less stable compost, which indicates that the biogas is mainly produced by the anaerobic digestion of the amended compost. Finally, it seems that compost addition is required to improve the process in some cases but in other circumstances it does not greatly improve the bioremediation of PAHs. [Copyright &y& Elsevier]

Abstract: The feasibility of using different organic amendments of different origin and properties in the bioremediation of pyrene-contaminated soil by means of composting has been tested. The selected pyrene concentration was 1g of pyrene per kg of dry soil. The organic amendments used include: raw organic fraction of municipal solid wastes (OFMSW), industrial compost from OFMSW composting (COFMSW), compost derived from home composting of OFMSW (HCOFMSW), anaerobically digested sludge (ADS), non-digested activated sludge (NDS) and centrifuged non-digested activated sludge (CNDS). The degradation rate was related to the amendment properties that directly affected the composting process. Raw OFMSW was not capable to enhance pyrene degradation in comparison to control, but stable HCOFMSW exhibited the highest removal rate (69%). The amendments stability and the temperatures reached as a consequence influenced the process, and thermophilic temperatures showed an inhibition effect on the microbial activity related to pyrene degradation. Some of the tested wastes need to be further investigated to find inexpensive organic amendments for soil bioremediation. [Copyright &y& Elsevier]

Organic waste generation, collection, and management have become a crucial problem in modern and developing societies. Among the technologies proposed in a circular economy and sustainability framework, composting has reached a strong relevance in terms of clean technology that permits reintroducing organic matter to the systems. However, composting has also negative environmental impacts, some of them of social concern. This is the case of composting atmospheric emissions, especially in the case of greenhouse gases (GHG) and certain families of volatile organic compounds (VOC). They should be taken into account in any environmental assessment of composting as organic waste management technology. This review presents the relationship between composting operation and composting gaseous emissions, in addition to typical emission values for the main organic wastes that are being composted. Some novel mitigation technologies to reduce gaseous emissions from composting are also presented (use of biochar), although it is evident that a unique solution does not exist, given the variability of exhaust gases from composting. [ABSTRACT FROM AUTHOR]

Composting has become a preferable option to treat organic wastes to obtain a final stable sanitized product that can be used as an organic amendment. From home composting to big municipal waste treatment plants, composting is one of the few technologies that can be practically implemented at any scale. This review explores some of the essential issues in the field of composting/compost research: on one hand, the main parameters related to composting performance are compiled, with especial emphasis on the maturity and stability of compost; on the other hand, the main rules of applying compost on crops and other applications are explored in detail, including all the effects that compost can have on agricultural land. Especial attention is paid to aspects such as the improvement of the fertility of soils once compost is applied, the suppressor effect of compost and some negative experiences of massive compost application. [ABSTRACT FROM AUTHOR]