Sewage Sludge Compost Research Articles

Evaluation of Composted Organic Wastes and Farmyard Manure for Improving Fertility of Poor Sandy Soils in Arid Regions

Farmyard manure, an amendment traditionally used for improving the fertility of sandy soils in arid climates, is becoming scarce and expensive. Its shortage makes it necessary to evaluate, at field scale, the suitability and medium-term performance of other cheap, highly available substitutes. A field trial was established to analyze the effects of a single application of three organic residues on barley yield and nutrient uptake and selected soil properties after two consecutive harvests. Municipal solid waste compost (MSWC), sewage sludge compost (SSC) and farmyard manure (FYM) were tested at rates of 0, 20, 40 and 60 t ha−1. Adding all three organic amendments increased organic matter, cation exchange capacity and available P, Ca, Mg and K in the soil, the grain yield (up to 51%), and the barley plants’ nutrient contents. After the second harvest, a positive residual effect of the amendment was observed in plant yield (up to 77%) and nutrient contents. MSWC and SSC induced slight increases on the extractable fractions (BCR protocol) of Co, Cu and Ni, relative to the unamended soil. The results demonstrate the positive immediate and residual effect of the amendments evaluated as fertilizers for agricultural purposes.

Qualitative investigation of sewage sludge composting: effect of aerobic/anaerobic pretreatments

Treatment and recycling of organic waste play important roles in an integrated waste management system by producing a stabilized material that can be utilized as a source of nutrients and as a soil conditioner. In this study, the viability of composting for the recycling of sewage sludge and also the possible effects of pretreatment under various conditions on the quality of the end-product were examined. Waste sewage sludge was obtained from a wastewater treatment plant in Hamedan, Iran, and was subjected to aerobic and anaerobic digestions. After analyzing the physicochemical properties of the digest, both treated sludges were composted. A third reactor was also set as control by direct composting of sewage sludge without pretreatment. The composting process was controlled by the measurement of the physicochemical properties of the substrate during and at the end of the process. The results of the analyses showed a substantial decrease in the C/N ratio, pH, volatile solids (VSS), total organic carbon, as well as pathogenic populations; however, a significant increase was observed in the ash and nitrogen contents in the compost obtained after anaerobic digestion. Accordingly, it was decided that the compost obtained, especially after anaerobic digestion, showed adequate degrees of maturity and stability and reflected characteristics, which based on national and international standards made it suitable for agricultural use.

Restoration and risk reduction of lead mining waste by phosphate-enriched biosolid amendments

Lead (Pb) contamination in environment has been identified as a threat to human health and ecosystems. In an effort to reduce the health and ecological risks associated with Pb mining wastes, a field study was conducted to stabilize Pb using phosphate (P)-enriched biosolid amendments in the contaminated mining wastes (average of 1004 mg Pb kg−1) located within the Jasper County Superfund Site, southwest Missouri. Experiments consisted of six biosolid amendment treatments, including Mizzou Doo compost (MD); Spent mushroom compost (SMC); Turkey litter compost (TLC); Composted chicken litter (CCL); Composted sewage sludge (CSS); and Triple superphosphate (TSP). Kentucky tall fescue seeds were planted following the treatments, and soil and plant samples were collected and analyzed 8–10 years post treatment. Results indicated that, in all cases, the biosolid treatments resulted in significant reductions in bioaccessible Pb (96.5 to 97.5%), leachable Pb (95.0 to 97.1%) and plant tissue Pb (45.5 to 90.1%) in the treated wastes, as compared with the control. The treatments had no significantly toxicological effect to soil microbial community. Analysis of the Pb fractionation revealed that the Pb risk reduction was accomplished by transforming labile Pb fractions to relatively stable species through the chemical stabilization reactions as induced by the treatments. The solid-phase microprobe analysis confirmed the formation of pyromorphite or pyromorphite-like minerals after the treatment. Among the six biosolid amendments examined, SMC and MD treatments were shown most effective in the context of Pb stabilization and risk reduction. This field study demonstrated that the treatment effectiveness of Pb stabilization and risk reduction in mining wastes by P-enriched biosolid amendments was long-term and environmental-sound, which could be potentially applied as a cost-effective remedial technology to restore contaminated mining site and safeguard human health and ecosystems from Pb contamination.

Can the Application of Municipal Sewage Sludge Compost in the Aided Phytostabilization Technique Provide an Effective Waste Management Method?

(1) Background: sewage sludge is a by-product of wastewater treatment, which needs to be managed appropriately, e.g., in composting processes. The application of municipal sewage sludge composts (MSSCs) as a soil amendment is a potential way to effectively manage sewage sludge. (2) Methods: this paper presents the results of a vegetation pot experiment undertaken to assess the suitability of Dactylis glomerata L. and MSSC in the aided phytostabilization technique when applied on soils from an area effected by industrial pressure; this is characterized by high levels of heavy metal (HM). The contents of HMs in the test plant (the roots and above-ground parts), as well as in the soil and MSSC, were determined via an atomic spectrometry method. (3) Results: the application of MSSC positively contributed to an increased production of plant biomass and an increase in the pH in the soil. Concentrations of Cu, Cd, Pb, Zn, and Cr were higher in the roots than in the above-ground parts of Dactylis glomerata L. The addition of MSSC contributed most significantly to the considerable reduction in Ni, Pb, and Zn contents in the soil after the experiment. (4) Conclusions: MSSC can support the phytostabilization of soils contaminated with high levels of HMs.

Microplastics in soils: an environmental geotechnics perspective

Microplastics (MPs) are emerging persistent contaminants in the terrestrial subsurface, and evidence has emerged for significant effects of MPs on the biological and ecosystem functions of soils. Main MP sources include land spreading of sewage sludge and biowaste composts, plastic mulching film used in horticultural fields, waste water irrigation and leachate from the landfills, among others. This updated state-of-the-art review paper describes recent experimental and numerical research and developments in understanding the accumulation and fate and effects of MPs in the soil environment (focusing on their storage, degradation, transportation, leaching to groundwater etc.), followed by mitigation and bioremediation measures, including MP-eating soil bacteria and fungi and the best management practices for reducing MP pollution of soil. Other areas covered are the combined effects of MPs and various other environmental contaminants (heavy metals, organic pollutants and antibiotics) in soil ecosystems and the standardisation of methods for detection, quantification and characterisation of MPs in soils, which is critical for MP research. The paper concludes by identifying knowledge gaps and presents recommendations on prioritised research needs.

The behavior of antibiotic-resistance genes and their relationships with the bacterial community and heavy metals during sewage sludge composting

The main contributors to antibiotic resistance genes (ARGs) profiles during the composting process under the addition of biochar (BC) and peat (PT) were not fully explored. This study investigated the influence of BC and PT amendment on ARGs fate, the bacterial community and heavy metals in sewage sludge compost. Compared to control, BC and PT declined the total abundances of ARGs by 17.6% and 43.0% after composting. Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria were the dominant phyla across the composting process, among which, members of Firmicutes (mainly Bacillaceae) were the potential hosts for multiple ARGs. BC and PT addition declined the abundance of bacterial pathogens such as Bacteroides and Pseudomonas. Besides, the concentrations of copper (Cu), zinc (Zn) and lead (Pb) were less in BC and PT treatments than control on day 40, and these metals displayed significant positive correlations to sul1 and intI1. Furthermore, variation partitioning analysis (VPA) revealed that the bacterial community exhibited the most contribution to the ARG patterns, as much as 34.0%, followed by heavy metals (10.8%) and intI1 gene (1.5%). These results suggested that biochar and peat can reduce the risks of ARGs in sewage sludge mainly by sharping the bacterial composition.

Effect of Sewage Sludge Compost Usage on Corn and Faba Bean Growth, Carbon and Nitrogen Forms in Plants and Soil

Sewage sludge is an effective fertilizer in many soil types. When applied as an amendment, sludge introduces, in addition to organic matter, plant nutrients into the soil. When applied for cropland as a fertilizer, the mass loading of sewage sludge is customarily determined by inputs of N and/or P required to support optimal plant growth and a successful harvest. This study aims to examine the changes in organic matter contents and nitrogen forms in sludge-amended soils, as well as the growth of corn and faba bean plants. The main results indicated that there were higher responses to the corn and faba bean yields when sludge was added. Levels of organic carbon in soil were higher after maize harvest and decreased significantly after harvesting of beans, and were higher in sludge amended soils than unmodified soils, indicating the residual effect of sludge in soil. NO3−-N concentrations were generally higher in the soil after maize harvest than during the plant growth period, but this trend was not apparent in bean soil. The amounts of NH4+-N were close in the soil during the growth period or after the maize harvest, while they were higher in the soil after the bean harvest than they were during the growth period. Total nitrogen amounts were statistically higher in the soil during the growth period than those collected after the corn harvest, while they were approximately close in the bean soil. The total nitrogen amount in corn and bean leaves increased significantly in plants grown on modified sludge soil. There were no significant differences in the total nitrogen levels of the maize and beans planted on the treated soil.

Predicting relative agronomic efficiency of phosphorus-rich organic residues

Relative agronomic efficiency (RAE) of phosphorus (P) in nutrient-rich residues with different chemical characteristics must be known in order to optimize their use as fertilizers, to avoid underfertilization of crops or eutrophication of surface waters due to overfertilization. In this study, we determined the chemical characteristics and RAE of manures (cattle, pig, fox) and sewage sludges subjected to different treatments (anaerobic digestion, composting, lime stabilization, thermal hydrolyzation, pyrolyzation, hydrothermal carbonization (HTC)) by growing barley (Hordeum vulgare, var. Elmeri) to maturity in three independent growth trials. All manures had high RAE (up to 189% in pig slurry), while RAE was only 6–17% for digested and composted sewage sludges when precipitation with Fe used for P removal from wastewater. Pyrolyzation and HTC further depressed RAE to 1–6%. Alternative wastewater treatment processes are therefore needed to increase P recycling potential. For cattle and pig manures and anaerobically digested or composted sewage sludges, molar ratio of (Fe + Al)/P, varying from 0.08 to 2.69, was the best predictor of RAE (R2 = 0.99), with negative correlations with grain yield. Sources in which calcium was more influential for P solubility (fox manure and lime-stabilized sewage sludge) and pyrolyzed and HTC-treated residues did not follow this trend. Conventional extraction methods (2% formic acid, 2% citric acid, neutral ammonium citrate, water and 0.5 M NaHCO3) either underestimated or overestimated RAE of P-rich organic residues, depending on their chemical characteristics.

Nitrous oxide emissions, ammonia volatilization, and grain-heavy metal levels during the wheat season: Effect of partial organic substitution for chemical fertilizer

Wheat is one of the most important staple foods worldwide, and the organic substitution for chemical fertilizer has been increasingly receiving attention in wheat planting. However, its impact on nitrous oxide (N2O) emissions and ammonia (NH3) volatilization from the wheat fields, as well as on the heavy metal [Nickel (Ni), Copper (Cu), Zinc (Zn), Cadmium (Cd), and Lead (Pb)] contents in the wheat grain is poorly known. A two-year field experiment was performed with two organic manures (sewage sludge compost and pig manure compost) and two substitution ratios (25 % and 50 %) for chemical nitrogen (N) fertilizer during the wheat season. An increasing trend in wheat yield (0.33∼5.9 %) was observed and total N2O emission was significantly decreased by 33∼77 % with partial organic substitution (POS). Therefore, the fertilizer-induced N2O emission factor was highly decreased (0.12∼0.47 % VS. 0.77∼0.92 %). The POS relatively increased NH3 volatilization by 7.9∼17 % (p > 0.05) and as a whole, it played little role in the cumulative N losses of N2O and NH3. The concentrations of Ni, Cu, Zn, Cd, and Pb in wheat grain were 97.4∼335 μg kg−1, 4.51∼5.88 mg kg−1, 28.5∼47.5 mg kg−1, 24.7∼79.6 μg kg−1, and 16.6∼33.4 μg kg−1, respectively. Although POS relatively increased the contents of Cu and Zn, they were all lower than those of the food standard limit for wheat in China. Moreover, the values of metal pollution index (0.39∼0.71) in all treatments were less than one. Our health risk assessment further demonstrated that POS did not pose any health risks. The findings suggest that partial replacement of chemical fertilizer with sewage sludge compost and pig manure compost in the wheat season can significantly decrease N2O emissions while not increasing N losses or compromising yield and its quality.

Effects of Sewage Sludge Stabilization Processes on Soil Fertility, Mineral Composition, and Grain Yield of Maize in Successive Cropping

The final disposal of sewage sludge (SS) in agricultural areas is considered economically and environmentally viable, but few studies on the effects of sludge stabilization processes on SS fertilizing potential are available. The present study evaluated two forms of SS stabilization on the shoot biomass, yield, and concentration of nutrients in the soil and plants in three successive maize croppings. The raw sludge was chemically stabilized (CSS) and composted (TSS) through the addition of calcium oxide and co-composting with plant residues, respectively. Five rates of each type of SS (0, 10, 20, 30, and 40 t ha−1 dry weight) were applied to the soil in a family farm of NE Brazil. A mineral fertilization treatment was used to assess the SS fertilizer potential. Changes in soil chemical characteristics (pH, organic matter, and nutrient available contents), plant mineral composition, and maize biomass and yield were assessed at each crop cultivation. Applying sewage sludge to the soil elevated the soil organic matter and the availability of N, P, Fe, Mn, Zn, and Cu, reflecting in higher accumulation of these nutrients by plants. The CSS was more efficient in increasing soil pH than SS composting. In the first harvest, maize yield in CSS was 34% higher than that obtained with mineral fertilization. The two types of sludges had different effects on soil characteristics, plant mineral composition, and maize yield. The CSS residual effect on soil pH can dismiss soil liming. Composted sludge maintained higher soil organic matter levels in the soil with the successive croppings and promoted higher soil N concentrations in the first two croppings. Both sludges increased and maintained adequate available P concentrations in the soil throughout the successive crops. The results support SS’s efficiency in providing nutrients to plants, improving soil properties, and boosting crop productivity in low-input agriculture systems.

Improving sewage sludge compost process and quality by carbon sources addition

In present study, the effects of carbon sources on compost process and quality were evaluated in the lab-scale sewage sludge (SS) composting. The composting experiments were performed for 32 days in 5 L reactors. The results showed that carbon sources could change the nitrogen conversion and improve the compost quality. Especially, the readily degradable carbon source could promote organic matter degradation, improve nitrogen conversion process and accelerate compost maturation. The addition of glucose and sucrose could increase dissolved organic carbon, CO2 emission, dehydrogenase activity, nitrification and germination index during the SS composting. That's because glucose and sucrose could be quickly used by microbes as energy and carbon source substance to increase activity of microbes and ammonia assimilation. What's more, the NH3 emission was reduced by 26.9% and 32.1% in glucose and sucrose treatments, respectively. Therefore, the addition of readily degradable carbon source could reduce NH3 emission and improve compost maturity in the SS composting.

Insight into metal immobilization and microbial community structure in soil from a steel disposal dump phytostabilized with composted, pyrolyzed or gasified wastes

The soil system is a key component of the environment that can serve as a sink of pollutants. Using processed waste for aided phytostabilization of metals (HMs) in contaminated soils is an attractive phytoremediation technique that integrates waste utilization and recycling. In this study, we evaluated the effect of biologically and thermally processed wastes, i.e. sewage sludge compost (CSS), poultry feather ash (AGF) and willow chip biochar (BWC), on phytostabilization of contaminated soil from a steel disposal dump. Greenhouse experiments with Lupinus luteus L. and amendments (dosage: 3.0%, w/w) were conducted for 58 days. Soil toxicity was evaluated with Ostracodtoxkit and Phytotoxkit tests. At the end of the experiment, soil pH, plant biomass yield, and HM accumulation in plant tissues were determined. HM distribution, HM stability (reduced partition index) and potential environmental risk (mRI index) in the soil were assessed. During phytostabilization, changes in the diversity of the rhizospheric bacterial community were monitored. All amendments significantly increased soil pH and biomass yield and decreased soil phytotoxicity. AGF and BWC increased accumulation of individual HMs by L. luteus roots better than CSS (Cu and Cr, and Ni and Zn, respectively). The soil amendments did not improve Pb accumulation by the roots. Improvements in HM stability depended on amendment type: Ni and Pb stability were improved by all amendments; Zn stability, by AGF, and BWC; Cd stability, by AGF; and Cr stability, by BWC. AGF reduced the mRI most effectively. Microbial diversity in amended soils increased with time of phytostabilization and was up to 9% higher in CSS amended soil than in control soil. AGF application favored the abundance of the genera Arenimonas, Brevundimonas, Gemmatimonas and Variovorax, whose metabolic potential could have contributed to the better plant growth and lower mRI in that soil. In conclusion, AGF and BWC have great potential for restoring steel disposal dump areas, and the strategies researched here can contribute to achieving targets for sustainable development.

Influence of Decreasing Supplementation to Transformation of Chemical Forms of Ni, Zn and Cu During Composting of Sewage Sludge

This paper pertains to the influence of decreasing supplementation to transformation of chemical forms of Ni. Zn and Cu during composting of sewage sludge. A universally used supplementing material constituting a rich source of organic carbon is straw. Addition of straw to sewage sludge is aimed at increasing C/N proportion up to at least 15 due to the risk of formation of toxic forms of nitrogen, concentration of which in sewage sludge is exceptionally high. We have presented in this paper the results of speciation research of three elements applying Tessier’s sequential extraction. It’s been proven that decreasing of straw share in the composted mixture with sewage sludge down to the level of C/N value below the admissible value, has a beneficial effect on the allocation of tested heavy metals towards the forms that are permanently bound in compost matrix. A systematic increase of organic (IV) and residual (V) fractions share and decrease of mobile forms of heavy metals content in bioavailable fractions i.e. ion-exchange (I) and carbonate (II) has been ascertained.

Effects of Initial Particle Sizes of <i>Triarrhena Lutarioriparia</i> on Processing Performance, Material Properties, and Heavy Metal Speciation in Sewage Sludge Composting

Effects of Initial Particle Sizes of <i>Triarrhena Lutarioriparia</i> on Processing Performance, Material Properties, and Heavy Metal Speciation in Sewage Sludge Composting

Biodegradation mechanism of typical fluoroquinolones in sewage-sludge composts

Biodegradation mechanism of typical fluoroquinolones in sewage-sludge composts

Hyper-Thermophilic Composting of Sewage Sludge and Ash Alkali Composting of Feces Provide Excellent Organic Fertilizers for Sustainable Agriculture

Hyper-Thermophilic Composting of Sewage Sludge and Ash Alkali Composting of Feces Provide Excellent Organic Fertilizers for Sustainable Agriculture

Effect of Sewage Sludge Compost Application on the Taste of Fruit Vegetables Compared with Chemical Fertilizer Application

Effect of Sewage Sludge Compost Application on the Taste of Fruit Vegetables Compared with Chemical Fertilizer Application

The Hyper-Thermophilic Composting Sewage Sludge and the Ash Alkali Composting Feces are Excellent Organic Fertilizers for the Sustainable Agriculture

The Hyper-Thermophilic Composting Sewage Sludge and the Ash Alkali Composting Feces are Excellent Organic Fertilizers for the Sustainable Agriculture

Crescimento de mudas de Lafoensia glyptocarpa utilizando lodo de esgoto compostado e diferentes lâminas de água

Avaliou-se o crescimento de mudas de mirindiba (Lafoensia glyptocarpa Koehne) em diferentes concentrações de lodo de esgoto compostado (LEC), substrato comercial (SC) e lâminas de água (L). O delineamento experimental, em parcelas subdivididas, contou com 4 repetições, dispostas em 3 L e 5 diferentes tratamentos. Avaliou-se: altura, número de folhas, diâmetro do coleto, massa seca das raízes e parte aérea e o índice de qualidade de Dickson (IQD). O uso de SC + LEC apresentou os melhores resultados nos diferentes parâmetros, porém, o IQD sugere o uso de 100% LEC com irrigação L2 (25,5 mm 9 min ao dia).

Nitrogen Isotope Fractionation during Composting of Sewage and Agri-Food Sludge with Pruning Waste

This work studies the changes in δ15N signature during the composting of sewage sludge (MS) and agri-food sludge (AS) with different bulking agents and the potential relationships between the changes in this parameter with both the source of the organic matter used as a raw material and the stability of the end-materials obtained. For this, eleven mixtures were prepared in commercial composting conditions using sewage sludge from municipal wastewater in a range of 60–85% (on a fresh weight basis) or agri-food sludge in a range of 65–75%, mixed with seven different pruning wastes as bulking agents. The thermal profile was monitored throughout the composting processes, and the main physico-chemical and chemical parameters were determined. The results obtained confirmed a correct development of the composting processes, observing slight differences in process evolution depending on the type of sludge used. The composts obtained showed adequate contents of nitrogen, phosphorus and potassium (NPK) and reached a good degree of maturity. Significant differences in the specific nitrogen isotopic composition were found in the initial materials. Moreover, the results suggest that the type of sludge had a main contribution in the δ15N value of the initial composting mixtures. The use of δ15N is recommended as an indicator of the composting process, especially to evaluate N dynamics, and the quality of the resultant compost.