Application of Sewage Sludge on an Acid Tropical Soil: Crop Response and Heavy Metals Uptake by Maize and Their Accumulation in The Soil

At present, Malaysia produces about 5 million m3 sludge per year (wet weight basis). Land application of sewage sludge is considered the most economical and also provides an opportunity to recycle beneficial plant nutrients and organic matter to soil for crop production. However, sewage sludge also contain varying amounts of heavy metals which may pose a hazard of metal toxicity to crops and the consumer of these crops. Thus the uptake of heavy metals by crops and the fate of these heavy metals in soils need to be monitored. The first study, which involved ten sewage sludges, were collected from different wastewater treatment plants and classified into domestic sludge (type A) and light-industry sludge mixed with domestic sludge (type B). The chemical properties of sewage sludge with emphasis on heavy metal content were determined. In general, type B sludge has higher heavy metal content than type A sludge. The concentration of heavy metals in these sludges did not exceed the maximum permitted concentrations (MPC) of the European Community Standard (ECS), for land application, except for Zn (7110.10 mg kg-I). Also, the Cu concentration is rather high in type B sludge. Therefore, type B sludge can be characterized as quite hazardous and unsuitable for agricultural use

Effect of vermicompost application on bioactive properties and antioxidant potential of MD2 pineapple fruits

Vermicompost is an organic waste produced from earthworms that can enhance the soil condition and is rich with essential plant nutrients, thus increasing produce quality and shelf life. In this study, a one-year field trial was conducted to elucidate the effects of vermicompost supplementation on the composition of bioactive compounds and antioxidant activities of pineapple (Ananas comosus var. MD2) fruits, compared to control and application of chemical fertilizer. Based on the results, pineapple fruits produced from plants supplemented with chemical fertilizer showed the strongest radical scavenging properties against 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,20-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), followed by vermicompost and control plants. Application of chemical fertilizer and vermicompost also produced fruits with a very high content of chlorophylls and β-carotene compared to control plants. However, the amounts of bioactive compounds present in fruits produced with chemical fertilizer are higher than in fruits produced with vermicompost. Total phenolics content and Ferric Reducing Antioxidant Power (FRAP) reducing power were lowest in fruit extracts produced from pineapple plants supplemented with vermicompost. These results suggested that vermicompost cannot completely replace chemical fertilizer for the production of fruits with a high content of phytoconstituents but could be used as an additional supplement to reduce environmental pollution and ensure agricultural sustainability

Assessment on the quality of recycled paper mill sludge mixed with oil palm empty fruit bunch compost.

Recycled Paper Mill Sludge (RPMS) is currently disposed off in the landfill and the costs are becoming expensive. Therefore, an alternative disposal through land application of RPMS and empty fruit bunches (EFB) (as a bulking agent) compost requires investigation. This study was conducted to determine the physico-chemical characteristics of composted RPMS and EFB mixtures, their phytotoxicity and the effect of the composts on plant growth performance. Composting experiment was arranged in a completely randomized design (CRD) with four replicates. The RPMS were mixed with EFB in 3 ratios, that is 1:1, 1:2 and 1:3 (RPMS: EFB) based on volume/volume. The mixtures were filled in a polystyrene box up to 90% volume and water was sprinkled onto the compost (50% moisture content) to accelerate decomposition. During composting, the compost was turned every three days to ensure that the material on the outside of the pile was turned from the center outwards to dissipate heat. The RPMS and EFB compost mixtures were evaluated for physical, chemical, phytotoxicity and short term plant growth effects. These composts mixtures had no toxicity effects on plants, had 100% seed germination, high in nutrient contents, low in C/N ratio and had fine particle size of <18 mm. The concentrations of heavy metals were also within the recommended level of the Council of European Communities (CEC) for compost. Compost produced from a ratio of 1:1 volume is suitable for land application as compared to 1:2 and 1:3 (RPMS: EFB). However, further study should be carried out to evaluate the effect of raw and RPMS compost on soil fertility, plant productivity and quality

Application of waste raw and composted recycled paper mill sludge on orthosiphon stamineus and its effects on heavy metals in soil

The paper industry plays a major role in the global economy of the world. A study was conducted on the waste paper mill sludge applied on the Orthosiphon stamineus for 4 crop cycle for 1 year growth at Glasshouse, Faculty of Agriculture, Universiti Putra Malaysia. Waste Paper Mill Sludge (PMS) and waste composted Recycled Paper Mill Sludge (RPMS) was used with nitrogen (0, 100, 200 and 400 kg ha-1) at the ratio of 1:1 (Recycled Paper Mill Sludge (RPMS): Empty Fruit Brunch (EFB). The growth parameters were measured twice a month for 6 months. Plant nutrients and heavy metals uptake were determined. The paper mill sludge has the potential to be a supplementary N fertilizer as well as a soil amendment. The application of waste RPMS with N significantly contributed to the improvement in plant dry matter (28.5 g plant-1) and improved soil physical and chemical properties. Total concentrations of heavy metals in soils were below the critical values. Hence, the waste paper mill sludge can be successfully used as soil amendment in acidic soil without any serious threat. The use of waste paper mill sludge for the soil fertility showing improvement in land application signifies a unique opportunity to recycle sludge back to the land to alleviate the potential waste management problem

Characterization and feasibility assessment of recycled paper mill sludge for land application in relation to the environment

The disposal of industrial paper mill sludge waste is a big issue and has a great importance all over the world. A study was conducted to determine the chemical properties of recycled paper mill sludge (RPMS) and assess its possibilities for land application. RPMS samples were collected from six different paper mills in Malaysia and analyzed for physical and chemical properties, heavy metals, polycyclic aromatic hydrocarbons, (13)C-NMR spectra and for the presence of dioxins/furans. The RPMS was dewatered, sticky with a strong odour, an average moisture of 65.08%, pH 7.09, cation exchange capacity (CEC) 14.43 cmol (+) kg(-1), N 1.45, P 0.18, K 0.12, Ca 0.82, Mg 0.73, Na 0.76 and Al, 1.38%. The polycyclic aromatic hydrocarbons (PAHs) and heavy metals levels were below the standard Class 2 limits. The dioxin and furan were in below the standard concentration of Class 1. The most prominent peak in the (13)C-NMR spectra of RPMS was centered at 31 ppm, proving the presence of methylene (-CH2) groups in long aliphatic chains, with lipids and proteins. The signal at 89 ppm and highly shielded shoulder at 83 ppm were due to presence of cellulose carbon C-4, and the peak at 63 and 65 ppm was due to the cellulose carbon spectrum. The RPMS therefore contains significant amount of nutrients with safe levels of heavy metals and PAHs for environment and can be used as a fertilizer and soil amendment for land application

Application of raw and composted recycled paper mill sludge on the growth of Khaya senegalensis and their effects on soil nutrients and heavy metals

The paper industry performs an essential role in the global economy of the world. A study was conducted on the paper mill sludge that is applied on the Khaya senegalensis for 4 crop cycle for 1 year growth at glasshouse, Faculty of Agriculture, Universiti Putra Malaysia. Paper Mill Sludge (PMS) and composted Recycled Paper Mill Sludge (RPMS) was used with nitrogen (0, 150, 300 and 600 kg ha-1) at the ratio of 1:1 (Recycled Paper Mill Sludge (RPMS): Empty Fruit Bunch (EFB). The growth parameters were measured twice a month for 6 months. Plant nutrients and heavy metal uptake were determined. The paper mill sludge has the potential to be a supplementary N fertilizer as well as a soil amendment. The application of RPMS with N, significantly contributed to the improvement in plant growth parameters such as plant height (193 cm), basal diameter (27.00 mm), total plant biomass and improved soil physical and chemical properties. Total concentrations of heavy metals in soils were below the critical values. Hence, the paper mill sludge can be successfully used as soil amendment in acidic soil without any serious threat. The use of paper mill sludge for soil fertility, shows improvement in land application and signifies a unique opportunity to recycle sludge back to the land to alleviate the potential waste management problem

Chemical profile and antimicrobial activity of essential oil and methanol extract from peels of four Durio zibethinus L. varieties

Durio zibethinus L. (durian) belongs to the Malvaceae family. It is known as the “King of Tropical Fruit” because of its unique characteristics. The edible part of durian, however, is only about 33% of the fruit while the non-edible parts such as the seed and peels (rinds) are considered as fruit waste responsible for environmental pollution. Thus, the present study was carried out to compare the percentage yields and volatile components from methanol extract and essential oils of the peels of four varieties of durian (Raja Kunyit [D197], Hajah Hasmah [D168], Sultan [D24], and Golden Bun [D13]). The antimicrobial activity of all the extracts and their volatile chemical constituents were also evaluated. Cold maceration was used for the solvent (methanol) extraction. The essential oil extraction was carried out using hydro-distillation and solventfree microwave extraction (SFME) methods. The antimicrobial activity was evaluated against selected microbes using the well difusion method while the characterization of chemical constituents in the essential oils and crude methanolic extracts was carried out using gas chromatography-mass spectrometry (GC–MS). The highest yields of essential oils were obtained from D24 which were 0.030% and 0.014% from SFME and hydro-distillation extraction, respectively, while the highest and most signifcant (p<0.05) yield of methanol extract (8.79%) was obtained from D197. From the GC–MS analysis, butanoic acid was the major compound in the essential oil of durian peels in the four varieties of durians evaluated. Besides butanoic acid, 1-tridecene, 1-pentadecene, and 1-heptadecene were also present in the four varieties. The D168 possesses strong activity against three bacteria (Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa). More novel extraction techniques, bioactivity assays, and characterization are, however, recommended to further explore the potential benefts of durian peels

Characterization and Feasibility Assessment of Recycled Paper Mill Sludges for Land Application in Relation to the Environment

The disposal of industrial paper mill sludge waste is a big issue and has a great importance all over the world. A study was conducted to determine the chemical properties of recycled paper mill sludge (RPMS) and assess its possibilities for land application. RPMS samples were collected from six different paper mills in Malaysia and analyzed for physical and chemical properties, heavy metals, polycyclic aromatic hydrocarbons, 13C-NMR spectra and for the presence of dioxins/furans. The RPMS was dewatered, sticky with a strong odour, an average moisture of 65.08%, pH 7.09, cation exchange capacity (CEC) 14.43 cmol (+) kg–1, N 1.45, P 0.18, K 0.12, Ca 0.82, Mg 0.73, Na 0.76 and Al, 1.38%. The polycyclic aromatic hydrocarbons (PAHs) and heavy metals levels were below the standard Class 2 limits. The dioxin and furan were in below the standard concentration of Class 1. The most prominent peak in the 13C-NMR spectra of RPMS was centered at 31 ppm, proving the presence of methylene (-CH2) groups in long aliphatic chains, with lipids and proteins. The signal at 89 ppm and highly shielded shoulder at 83 ppm were due to presence of cellulose carbon C-4, and the peak at 63 and 65 ppm was due to the cellulose carbon spectrum. The RPMS therefore contains significant amount of nutrients with safe levels of heavy metals and PAHs for environment and can be used as a fertilizer and soil amendment for land application

Effects of land application of raw and composted recycled paper mill sludge on Khaya senegalensis and Orthosiphon stamineus

Recycled Paper Mill Sludges (RPMS) are complex mixtures of chemically recycled paper pulp, inorganic solid and chemical additives used in the paper manufacturing. These sludges are the final processed wastes from pulp and paper industries which are generated from different stages of papermaking. All paper industries produce sludge where disposal quantity is increasing every year which if not handled appropriately, led to environmental problem in the country. Since the usage of RPMS is restricted in Malaysia, studies on utilization of RPMS from Malaysian industries should be carried out to investigate the effect of RPMS on soil fertility, plant productivity and quality. The general objective of this study was to evaluate the effects of land application of raw and composted RPMS for agriculture and forestry applications in agroforestry system. Paper mill sludges have alkaline pHs ranging from 6.33 - 7.84 and thus can be important when utilized for acidic soil. Paper mill sludges contain total organic carbon ranging from 18.92 – 33.67% and organic matter content of 32.62 – 58.05% which can influence the biological, chemical and physical properties of soils. Paper mill sludges contain several essential plant elements including N (0.31 – 4.05%), P (0.02 - 0.08%), K (0.02 - 0.42%), Ca (0.36 - 1.28%) and Mg (0.41- 1.06%). In general, the concentrations of heavy metals (Cd, Cu, Ni, Mn, Pb and Zn) in the paper mill sludges did not exceed Class 2 of the categories proposed by British Columbia Pulp and Paper Association (2000). The spectrum of 13C NMR obtained in this study suggested that the RPMS exhibited peaks of cellulose and contains little lignin or hemicellulose like material. The FTIR spectrum complemented the structural information obtained in the 13C NMR spectrum. Similarly, environmental contaminants of harmful chemicals such as dioxins/furans and PAHs should not be of concern in RPMS as the levels were negligible. Therefore, RPMS can be safely used as a fertilizer or soil amendment for land application. Recycled paper mill sludge mixed with EFB fibres at 1:1 ratio was recommended to be suitable for land application in agriculture and forestry. From this study, the compost can be used as potting media and as soil conditioner enriched with plant nutrients or as a soil amendment to improve the biological, chemical or physical properties of a soil. Based on the potentially mineralizable N contents, double the rates of recommended inorganic fertilizer (300 and 200 kg N-1 of raw and RPM compost, respectively) were suggested for land application of Khaya senegalensis and Orthosiphon stamineus. Application of raw and RPMS compost produced higher dry matter yield and growth performance than the control treatments for Khaya senegalensis and Orthosiphon stamineus for glasshouse and field condition and were comparable to the inorganic fertilizer treatments. Based on carbon fractionation study, results after 1 year duration indicated that utilization of RPMS as organic amendment onto soil produced higher C and N contents in free and occluded light fraction (F-LF and O-LF) and particulate organic matter (POM). Meanwhile, the paper mill sludge application has significantly reduced the soil bulk density in the top soil which significantly affects the soil structure. However, the resonance peaks of any type of C structure in the soil remained completely unobservable even after removal of the magnetic materials followed by HF extraction. The FTIR spectra in soil at various time of sampling exhibited the same absorbance which indicates that no qualitative changes occurred during 6 months and 1 year of raw and RPMS compost application compared with the control treatments under glasshouse and field conditions. Total concentrations of Cu, Ni, Pb and Zn in soils were below the Investigation Level for Malaysian soils which the levels are taken at the 95th percentile of the heavy metals data for agricultural soils. Meanwhile, the concentrations of Cd are below the Australian Ecological Investigation Level (EILs) of 3 mg kg-1. Concentrations of heavy metals in leaves were below the MPC value of the Malaysian Food Act 1983 and Food Regulation 1985. In the fractionation study, cadmium was dominant in the exchangeable fractions. Meanwhile, Cu, Ni, Mn, Pb and Zn occurred in the residual fraction. Application of raw and composted RPMS to soil showed an increase of concentration of Cu, Mn, Zn, Ni, Pb and As in the leachates at 15, 30, 60 and 120 cm soil depths compared to the control in the following order, NO3- > Zn > Mn > Cu > Ni > Pb > Cd. The concentration of NO3-, Cd, Cu, and Zn were below the established threshold value for drinking water by World Health Organization (WHO, 2008) guideline, which is the international guideline adopted by Malaysia. However, concentrations of Mn, Ni and Pb values were found to exceed the threshold value of WHO (2008) regulations. Therefore, heavy metals in the leachates need to be monitored until no more of these metals are released from the treated soil. This study indicated that using raw RPMS with addition of EFB (1:1) was able to improve the structure of raw RPMS as a compost product and potential as organic fertilizer to substitute for the inorganic N fertilizer. Hopefully, this research can be used as preliminary information and reference on utilization of raw and RPMS compost as soil amendment for land application especially in Malaysia

Effect of Vermicompost on Growth, Plant Nutrient Uptake and Bioactivity of Ex Vitro Pineapple (Ananas comosus var. MD2)

Vermicompost is a nutrient-rich organic waste produced from earthworms that is beneficial in enhancing the soil condition and has been reported to aid in improving the crop yield and quality. In the present study, a field trial was conducted using a randomized complete block design with four replicates to elucidate the effects of vermicompost application (compared to supplementation with chemical fertilizer and no fertilizer) on the productivity of ex vitro MD2 pineapple plants. Vermicompost was applied on the sandy loam soils at transplanting followed by a second application at 7 months after planting (MAP) at the rate of 10 t&middot;ha&minus;1, while chemical fertilizer was applied based on the recommended cultivation practice. Data analysis revealed that there was no significant difference between the plants treated with vermicompost and chemical fertilizer in terms of the plant height, number of leaves, length and width of D-leaves, stomatal density and stomatal size. However, the fruits produced with vermicompost amendment were smaller in size but contained higher total soluble solids, titratable acidity, total solids, ascorbic acid and total chlorophyll content compared to the fruits produced from plants supplied with chemical fertilizer. Based on the DPPH, ABTS and FRAP assays, the methanolic fruit extracts from the control plants showed the highest antioxidant potential, followed by those of plants treated with vermicompost and chemical fertilizer. On the other hand, the application of vermicompost reduced soil acidity and produced macro- and micronutrient contents (N, P, K, Mg, Ca, S, Fe, Zn, B and Al) in the soil and plants that were comparable to or higher than those produced by the chemical fertilizer treatment. However, some of the nutrient contents observed in all treatments were lower than the recommended range for pineapple plant growth, suggesting that vermicompost or chemical fertilizer should not be used alone as a source of nutrients for ex vitro MD2 pineapple plants under these soil and field conditions. However, vermicompost can be used as a supplement to increase the fruit chemical quality and maintain the soil quality for agricultural sustainability