- Email: [email protected]
Synergistic effect of fly ash in in-vessel composting of biomass and kitchen waste
Accepted Manuscript Synergistic effect of fly ash in in-vessel composting of biomass and kitchen waste Vivek Manyapu, Ashootosh Mandpe, Sunil Kumar PII: DOI: Reference:
S0960-8524(17)32174-0 https://doi.org/10.1016/j.biortech.2017.12.039 BITE 19294
To appear in:
Bioresource Technology
Received Date: Revised Date: Accepted Date:
14 November 2017 12 December 2017 13 December 2017
Please cite this article as: Manyapu, V., Mandpe, A., Kumar, S., Synergistic effect of fly ash in in-vessel composting of biomass and kitchen waste, Bioresource Technology (2017), doi: https://doi.org/10.1016/j.biortech.2017.12.039
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
SYNERGISTIC EFFECT OF FLY ASH IN IN-VESSEL COMPOSTING OF BIOMASS AND KITCHEN WASTE Vivek Manyapua, Ashootosh Mandpeb and Sunil Kumar*b a
Dr. A.P.J. Abdul Kalam fellow, Amity School of Earth and Environmental Sciences, Amity University Haryana, Gurgaon 122 413, India b
CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur 440 020, India *Corresponding author (Email): [email protected]
Abstract The present study aims to utilize coal fly ash for its property to adsorb heavy metals and thus reducing the bioavailability of the metals for plant uptake. Fly ash was incorporated into the invessel composting system along with organic waste. The in-vessel composting experiments were conducted in ten plastic vessels of 15 L capacity comprising varying proportions of biomass waste, kitchen waste and fly ash. In this study, maximum degradation of organic matter was observed in Vessel 3 having k value of 0.550 d-1. In vessel 10, 20% fly ash with a combination of 50% biomass waste and 30% kitchen waste along with the addition of 5% jaggery as an additive produced the best outcome with least organic matter (%C) loss and lowest value of rate constant (k). Keywords: Organic waste; in-vessel composting; fly ash; heavy metals; bioavailability
1
1. Introduction The global scale production of organic waste i.e., 100-300 kg person-1 year-1 (Jones and Healey, 2010) is proportional to the upsurging population of more than 7.5 billion (Population Reference Bureau, 2017). The agricultural production is rapidly intensified on the same piece of
land to fulfill the growing demands of food for such a huge population. This is done by the over-dosed application of chemical fertilizers and pesticides which strangle the soil to the apocalypse by releasing heavy metals into the soil. The soils in India are degrading at an alarming rate and to deal with this situation, attempts should be made for enrichment of soils with essential nutrients by using eco-friendly techniques. The compostable waste from municipal solid waste (MSW) accounts for about 39-54% in most of the cities of India (Kumar et al., 2009). More than 620 million tonnes (MT) of agricultural waste is generated in India every year (Singh and Sidhu, 2014). The huge amount of organic waste produced can be potentially utilized for agriculture to make the dying soils to be filled with life by nutrients enriched eco-friendly compost. There will be a reduction of 50-60% waste if it is converted into compost and thus will save the space used for landfilling and also emission of greenhouse gases (GHGs) can be prevented (Lou and Nair, 2009). The compost not only refills nutrients in the degrading soils but also lessens the huge burden of biomass waste from MSW, which is generated at the rate of 46.8 MT every year (Kumar, 2011). It is the compost which leads in the race among all other methods of organic waste management that include anaerobic digestion, landfilling and incineration, since it is easier to take up and manage (US EPA, 2009), economically being cheap (Murphy and Power, 2006), producing eco-friendly by-products and less GHGs emissions (Andersen et al., 2011). The
2
acceptable C:N ratio of combined feedstock can be 20:1 to 40:1 and ideal level can be 25:135:1. Acceptable Moisture Content (MC) can be 40-65% by weight, ideal being 45-60% (Rynk, 1992). The kitchen waste (KW) comprising 33.33% vegetable scraps, 33.33% fish waste and 33.33% newspaper gives satisfactory limits of MC about 59% and C/N ratio about 24.2 (Abdullah and Chin, 2010). Available oxygen >5% can be acceptable and ≥10% as ideal. Feedstock particle size <1 inch is acceptable. pH must be acceptable between 5.5-9 and ideal between 6.5-8 (Rynk, 1992). According to Central Public Health and Environment Engineering Organization (CPHEEO), Government of India, 2000, each of the NPK content should be >1% and the nitrate form of nitrogen should be present for regular uptake by plants. Compost maturity and stability can be confirmed by considering the respiration activity of the compost and its property of phytotoxicity (Wu et al., 2000). There are several types of composting methods for producing high-quality compost out of which four general methods adopted are windrow method, aerated static pile, vermicomposting and in-vessel composting (Cooperband, 2002; US EPA, 2000). Most of them are found to be sluggish. Since there is a highly alarming situation to eradicate the profuse biomass waste generated and also to replenish the dying soils, rapid composting systems need to be brought into the frame. Among the rapid composting systems, in-vessel system is one of the efficient compost producing methods. The in-vessel composting system is confined to a concrete tank, a metal/plastic vessel or container. There are variety of in-vessel methods vary with types of vessels used, turning mechanisms and aeration devices. With this system, one can control the composting process (Domínguez et al., 1997; US EPA, 2000). To rapidify the process of composting, additives can
3
be used. Among different additives used in composting process, jaggery showed best results (Gabhane et al., 2012). Among different energy sources, thermal energy is the main source of power in most parts of India contributing to 70% of the total generating capacity of India. Coal fly ash (FA) is one amongst the notorious byproducts produced during combustion of coal in thermal power stations (TPS) which is extremely stubborn to get eliminated from the ecosystem, causing environmental hazards, water and soil pollutions and ruination of ecological cycles (Yao et al., 2015). In India, out of 176.74 MT of FA generated by 151 TPSs, 107.77 MT is utilized for various purposes. During the lapse from 1996-97 to 2015-16, there was an increase of 6 folds in the utilization pecrcentage of FA, i.e. from 10% to 60.97% (Central Electricity Authority, 2016). Thus, in order to reduce the hazards and hindrances caused by this malignant matter, several types of research have been made to extract something good out of it. Worldwide, only 25% of the total FA generated is put into use (Wang, 2008). At present FA is put into potential applications viz. for soil amelioration, construction of roads, making bricks, synthesizing zeolite and as filler in polymers (Abdel Salam et al., 2011). It can also be used for heavy metal extraction, treatment of waste water for creating cenospheres (Asokan et al., 2005). Lime can be replaced by this noble powder because of its peculiar mechanisms that can reduce the bioavailability of heavy metals through physical adsorption and precipitate at high pH (Wong et al., 2009). Due to the presence of MgO and CaO, heavy metals get precipitated after adding coal FA to any compost or soil. Thus, reducing the heavy metal toxicity to plants grown in FA amended compost/soil (Wong et al., 1995). In the district of Nagpur, two prominent thermal power stations are located at Khapadkhera and Koradi with an installed capacity of 500 and 1100 Megawatts (MW), 4
respectively. Khaparkheda TPS generates 0.98 MT of FA and it utilizes 2.465% only. Koradi TPS generates 0.63 MT of FA and utilizes appreciable amount of FA (58.72%) (Central Electricity Authority, 2015). It was proved that co-composting FA with sewage sludge showed beneficial results (Fang et al., 1998). Furthermore, incorporating FA with the compost garnishes essential nutrients like silica, calcium oxide, alumina, magnesium oxide, iron oxide, potassium oxide, sodium oxide and sulphate (Singh et al., 2011). The nutrient values of FA get amassed with the compost without affecting the biological activity. If there is a high amount of FA amendments then it will pose hindrance in respiration of microbes (Wong and Wong, 1986). Though coal manifest is considered to be the most useful source of energy but the pollution caused due to the release of obnoxious gases by burning and the ashes produced create malignant havoc in the ecosystem producing hindrances in the natural flow of ecological cycles. Hence, a study was undertaken with an objective to investigate the effects of FA on different parameters (temperature, moisture, pH, C:N ratio, NPK content, heavy metal concentration and TC) with compost made out of brown waste (BW), green waste (GW) and KW in different proportions along with jaggery as an additive.
2. Materials and Methods 2.1. Sample Collection: Different BWs like dry leaves and branches were collected from tree shedding in the gardens of CSIR-NEERI, Nagpur. KW was collected from canteen of CSIRNEERI campus. GW comprising grass cuttings was collected from lawns after mowing. Coal FA was sampled out from Khaparkheda which is the coal-based TPS.
5
2.2. Substrate Analysis: The physical and chemical characteristics like pH (1:5 w/v waste:water) was measured by AQUASOL digital probe pH meter, MC (Gravimetric method); TC, TN, C:N ratio and Sulphur (Elementar Vario EL CHNS Analyser); Nitrate, Sulphate, Phosphate
(UV-1650pc, UV-VIS Spectrophotometer SHIMADZU); Cellulose and
Hemicellulose (Liu, 2004); Lignin (Klason’s method), COD (APHA, 1998), Heavy metal (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) concentration (ICP-OES, iCAP 6000 SERIES) of each substrate were analyzed. 2.3. Pre-treatment: All the substrates were shredded into 0.5-1 inches smaller pieces for increasing the surface area and porosity of substrate and ease the agitation process (Belyaeva and Haynes, 2009; Hendriks and Zeeman, 2009; Rawoteea et al., 2017; Rihani et al., 2010). They were then subjected to steam treatment to break down the high lignocellulose content. 2.4. Experimental Set-up: The experiment of in-vessel composting was conducted in ten plastic vessels of 15 L capacity each. Each vessel had a height of 32.5 cm. The top and base diameters being 28 cm and 23.6 cm, respectively. The vessels were having 20 small holes drilled at the base, aided with perforated rubber pipe internally to allow aeration through the 4 LPM (litres per minute) aerating pump. The ground substrates were made to form a mixture according to the proportions allotted and were loaded in the composting vessels along with microbial mixture, supplemented with additive presented in Table 1. 50 ml of a microbial mixture consisting of Trichoderma viride, T. harzianum and T. reesei was added in each vessel.
6
Table 1: Distribution of substrates in different vessels Vessels V-1 V-2 V-3 V-4 V-5 V-6 V-7 V-8 V-9 V-10
BW(g) 875 875 787.5 700 612.5 787.5 700 612.5 437.5 437.5
GW(g) 125 125 112.5 100 87.5 112.5 100 87.5 62.5 62.5
KW(g) X X X X X X X X 300 300
FA(g) X X 100 200 300 100 200 300 200 200
Additive (g) X 150 X X X 150 100 50 X 50
Microbial Mixture (ml) 50 50 50 50 50 50 50 50 50 50
In all the vessels, BW and GW were loaded in 7:1 ratio. Vessel 1 was loaded with BW and GW only. In Vessel 2, 15% jaggery as an additive was added along with ingredients of Vessel 1. Vessels 3, 4 and 5 contained 10%, 15% and 30% FA, respectively incorporated with BW and GW. Vessels 6, 7 and 8 contained 15%, 10% and 5% additive, respectively with same ingredients as in Vessels 3, 4 and 5. Vessel 9 contained 30% KW and 20% FA in addition to BW and GW. Vessel 10 contained an additive of 5% in addition to ingredients of Vessel 9. Total volatile solids (TVS) were determined as sample weight loss (previously ovendried at 105 oC) by muffling at 550 oC for 24 h (Said-Pullicino et al., 2007). Loss of OM was calculated using the initial (X1) and final (X2) ash contents according to the equation 1 (Paredes et al., 2000 and Bustamante et al., 2008). OM loss (%) = 100-100
………………………………(1)
2.5 Statistical analysis: Data referring to the OM losses produced throughout the composting process was fitted to a kinetic function by the Quasi-Newton algorithm. The algorithm estimated values of model parameters by minimizing the sum of squared differences between the experimental and calculated values with non-linear optimization using a Ky plot software to calculate the value of k. A first-order kinetic model was used for OM degradation during
7
composting (Bernal et al., 1996). This model was chosen as the best fit because it gave a randomized distribution of the residuals together with the lowest residual mean square (RMS) value (equation 2). OM loss (%) = A (1- e – kt) ……………………………………… (2) Where, A is the maximum degradation of OM (%C), k the rate constant (d-1) and t the composting time (d).
3. Results and Discussion 3.1. Physico-chemical characteristics of the substrates The physico-chemical characteristics of FA, BW, GW and KW used as feedstock in the composting process are presented in Table 2. The FA was having a neutral pH and would not hamper the composting process. KW had high moisture content (82.5%) which would be a good source of moisture for microbes. FA contained a very negligible amount of cellulose but its high hemicellulose and lignin content made it extremely resistant to degrade. KW had least lignin content as it contained cooked material. C:N ratio of the three substrates BW, GW and KW was found to be 19.62, 22.71 and 20.99, respectively which is optimal for composting but FA had very low C:N ratio of 1.79. Since FA was used in smaller proportion, its C:N ratio was neglected. It was of great concern to assay heavy metals because FA was being incorporated in the compost. Although the concentration of heavy metals was less than the permissible limits but Fe content was found to be higher in comparison to other elements.
8
Table 2: Comparison of physico-chemical characteristics of substrates
Sl. No.
Parameters
FA (Mean + S.D.)
BW (Mean + S.D.)
GW (Mean + S.D.)
KW (Mean + S.D.)
1
pH
6.95+0.05
5.94+0.04
5.19+0.03
5.48+0.05
2
MC %
0.17+0.02
45.96+0.48
60.25+0.5
82.50+0.4
3
Cellulose %
2+0.04
38+0.42
9+0.1
54+0.6
4
Hemicellulose %
94.5+0.8
30+0.5
85.5+0.4
64.5+0.23
5
Lignin %
88.75+0.61
41.5+0.3
41.25+0.5
31.75+0.45
-1
6
Nitrate (mg g )
0.02+0.01
15.25+0.24
55.74+0.4
62.08+0.3
7
Phosphate (mg g-1)
0.09+0.005
1.86+0.05
20.3+0.5
19.26+0.05
-1
8
Sulphate (mg g )
5.65+0.07
110.68+0.2
37.68+0.04
2.54+0.04
9
TC %
0.27+0.03
19.18+0.08
37.43+0.08
43.47+0.11
10
TN %
0.04+0.05
0.98+0.07
1.65+0.04
2.07+0.04
11
C:N
1.79+0.04
19.62+0.04
22.71+0.06
20.99+0.06
12
S%
0.02+0.003
0.08+0.005
0.14+0.008
0.13+0.07
13
Heavy metals (mg kg-1)
FA
BW
GW
KW
Indian permissible limits (Awasthi and Bhatnagar, 2000)
a)
Cd
0.24+0.005
BDL
BDL
BDL
3-6
b)
Co
4.06+0.06
0.05+0.006
3.08+0.06
0.06+0.008
n/a
c)
Cr
16.39+0.06
3.92+0.04
10.97+0.15
5.49+0.06
n/a
d)
Cu
14.49+0.06
6.33+0.05
11.29+0.06
4.82+0.05
135-270
e)
Fe
4,993.7+0.50
357.42+0.40
4,217.1+0.60
340.16+0.10
n/a
f)
Mn
92.39+0.39
12.44+0.4
78.25+0.3
11.07+0.09
n/a
g)
Ni
11.97+0.05
1.03+0.003
8.09+0.06
1.04+0.05
75-150
h)
Pb
4.15+0.05
1.92+0.04
2.80+0.15
1.41+0.02
250-500
i)
Zn
40.23+0.3
40.44+0.4
38.82+0.4
31.04+0.5
300-600
BDL - Below Detection Limit; n/a – data not available
3.2. Operational indices Measurement of pH and temperature was done thrice a day with the interval of four hours at 10:00, 14:00 and 18:00 hours, respectively and the average value was calculated. The values of mean and standard deviation are presented in Tables 2 through 4. Samples from each 9
vessel were assessed by drying at 105 oC for 24 hrs and OM was determined by the loss on ignition at 550o C (APHA, 1998) with an interval of three days from the beginning of the experiment. 3.3. Physico-chemical characteristics of the compost 3.3.1. Odour, Colour and Texture Except Vessels 9 and 10, all other vessels had an earthy odour. Vessels 9 and 10 had a little decaying odour due to the moisture which was present even after maturation. The KW was found to be responsible for high moisture content. Vessels 1 and 4 had a brown colour, while Vessels 2 and 3 had dark brownish colour. Vessel 5 to 10 had greyish appearance due to the presence of FA. FA was also present in Vessels 3 and 4 but was overcome by BW. Vessels 9 and 10 were soggy in texture while all others were having soil like texture (after sieving). 3.3.2. Volume reduction More than 60% volume reduction was observed in all Vessels, except Vessels 5 and 8 due to the presence of high amount of FA. 3.3.3. C:N Ratio C: N ratio is a very vital factor which decides the microbial activity for composting process. The carbon and nitrogen are used as an energy source and building the cell structure. If nitrogen content is less, it can be used up completely and the microbes will be devoid of nitrogen and some of them might die (Polprasert, 2007). Other organisms might act upon the stored nitrogen for building up their cell material. Thus, the carbon content is reduced to a significant level while recycling nitrogen. High C:N ratio will result in exploitation of nitrogen
10
from the soil, while low C:N ratio will have no effect in improvement of soil structure (Bhattacharyya et al., 2005). In vessels 1, 2 and 5, the C:N ratio was more than 25 while in all others it was found to be less than 25 and the least was found in vessel 10. 3.3.4. Potassium Vessels 2, 6 and 10 contained very high potassium content in comparison to others since they contained jaggery. Jaggery itself contains 1056 mg of potassium per 100 g (Singh, 2013). Potassium is an easily leachable element (Korb et al., 2005). This is the reason for potassium content which was less than 1% as recommended by Central Public Health and Environment Engineering Organization (CPHEEO) Government of India, 2000, for an ideal compost. 3.3.5. Phosphorus Vessel 10 had highest phosphorus (P) content due to the presence of FA and KW with jaggery. Also, vessels 2 and 6 had a good content of P due to high jaggery content. At the end of composting, the P content was increased in all the cases. The phosphorus is immobilized due to microbial action and also the water solubility of P reduced due to humification (Asija et al., 1984). 3.3.6. pH There was a pH drop at the initial stage in all the cases which was due to the formation of organic acids (Hagerty et al., 1973). Later, the pH moved to neutral because the organic acids got converted into CO2 and later the pH attained constancy. These typical changes in pH could be seen in Vessels 7 and 10 (Figure 1). The lag phase observed in the vessel 7 is caused
11
by the formation of organic acids (Sundberg, 2004). This might be due to the rise in temperature caused by improper ventilation (Smârs, 2002).
Figure 1: Variation of pH in different vessels
3.3.7. Temperature Due to microbial decomposition process, there was an initial rise in temperature (Figure 2). Later the temperature declined and became stable because of decreased microbial activity which resulted due to reduced levels organic matter (Hagerty et al., 1973). Only vessel 10 could attain the stability in temperature. In all other vessels, temperature varied. In Vessel 7, an abrupt increase in temperature was observed due to exaggerated microbial activity and later a fall in temperature was also seen.
12
Figure 2: Variation of temperature in different vessels
3.3.8. Heavy metals Arsenic could only be detected in FA (15.4 mg kg-1). Except for Vessel 1, all other vessels contained a high amount of iron content due to the presence of FA as substrate. All other heavy metals were below than the permissible limits (Awasthi and Bhatnagar, 2000). Vessel 10 contained a lower concentration of most of the heavy metals in comparison to others as presented in Table 3. The least concentration of the maximum heavy metals could be found in vessel 1 since it did not contain FA. There was a drastic loss of Arsenic and Tin. Other heavy metals had a significant accumulation in all the vessels due to the presence of FA. It can be inferred that the increase in heavy metal concentration was due to the partial decomposition of the substrate added in the in-vessel composting system.
13
Table 3: Comparison of physico-chemical parameters in different vessels after maturity
Sl. No .
Parame ters
V-1 (Mean + S.D)
V-2 (Mean + S.D)
1
TC(%)
32.09+0.5
29.40+0.4
2
TN(%)
1.15+0.03
1.09+0.01
3
C:N
27.90+0.6
26.97+0.3
4
S (%)
0.06+0.02
0.16+0.00 1
5
P (%)
6
K (%)
0.58+0.00 6 0.04+0.00 1
V-4 (Mean + S.D) 21.79+0.4 7 0.88+0.00 5
0.05+0.00 1
V-3 (Mean + S.D) 26.36+0 .36 1.08+0. 01 24.41+0 .41 0.15+0. 002 0.29+0. 002 0.02+0. 001
0.70+0.02
24.76+0.3 0.11+0.00 2 0.22+0.00 2 0.02+0.00 7
7 a)
As
b)
Cd
c)
Co
d)
Cr
e)
Cu
f)
Fe
g)
Mn
h)
Ni
i)
V-5 V-6 (Mean (Mean + S.D) + S.D) 13.87+0 20.59+0 .2 .3 0.53+0. 0.93+0. 005 005 26.17+0 22.14+0 .4 .5 0.08+0. 0.14+0. 005 002 0.18+0. 0.66+0. 006 005 0.02+0. 0.04+0. 001 001 Heavy Metals
V-7 (Mean + S.D) 16.11+0. 11 0.71+0.0 05 22.69+0. 6 0.12+0.0 02 0.07+0.0 02 0.03+0.0 01
V-8 (Mean + S.D)
V-9 (Mean + S.D)
V-10 (Mean + S.D)
17.17+0.2
25.51+0.4
20.54+0.4
0.72+0.00 5
1.05+0.05
0.91+0.005
23.85+0.6
24.30+0.4
22.57+0.43
0.13+0.00 3 0.06+0.00 2 0.02+0.00 1
0.15+0.00 4 0.05+0.00 1 0.03+0.00 1
0.19+0.005 0.86+0.004 0.05+0.001
15.37+0.3 7 0.19+0.00 5
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
0.21+0.00 4
0.11+0.00 3
0.18+0.00 4
0.11+0.005
8.93+0.5
7.96+0.4
9.75+0.45
8.18+0.45
43.67+0. 33 46.05+0. 29
35.33+0.3 7 40.37+0.3 7
45.71+0.5
42.47+0.44
70.41+0.4 3
0.20+0. 005 9.88+0. 4 48.39+0 .8 55.95+0 .43
0.12+0.00 4
9.15+0.07
0.14+0. 004 8.25+0. 45 47.91+0 .6 43.38+0 .35
0.15+0.006
6.76+0.06
0.26+0. 008 12.33+0 .3 82.32+0 .70 64.99+0 .4
50.70+0.3 5
39.44+0.4
9513+0.3 15
13244+0. 332
15598+ 0.628
10080+0. 793
12139+. 733
13404+ 0.402
12347+0 .429
11554+0.4 5
12765+0. 274
10828+0.72
295.95+0. 135 16.92+0.0 6
351.86+0. 284% 20.71+0.0 6
302.47+0. 33 15.27+0.0 5
5.97+0.03
4.94+0.05
4.88+0.05
j)
Se
BDL
BDL
Sn
5.14+0.08
5.01+0.02
4.95+0.02
l)
Zn
BDL 17.00+0.3 4 111.55+0. 08
BDL
k)
BDL 49.48+0.5 2 98.82+0.0 6
300.77+ 0.997 23.60+0. 05 6.27+0.0 4 BDL 6.09+0.1 7 83.70+0. 07
284.48+0.70 2
8.85+0.05
327.01+ 0.917 25.29+0 .06 10.56+0 .06 BDL 6.44+0. 22 83.92+0 .05
318.76+0. 595 23.49+0.0 6
6.64+0.03
293.44+ 0.68 24.30+0 .07 7.00+0. 06 BDL 8.13+0. 12 67.97+0 .04
282.59+0. 424 19.48+0.0 6
Pb
405.60+ 0.493 37.96+0 .06 8.09+0. 06 BDL 10.68+0 .36 111.34+ 0.08
72.51+0.0 5
84.76+0.0 4
63.92+0.06
30.23+0.4 8 49.42+0.4 2
35.39+0.5
6.81+0.3 24.54+0.5 38.77+0.4
6.70+0.04 BDL 10.54+0.4 4 73.50+0.0 8
22.03+0.05
BDL-Below Detection Limit
3.3.9. Organic matter (OM) Evaluation of changes in OM content was used to characterize the different phases of composting as well as the relative completion of the composting process (Hubbe et al., 2010).
14
The data was analyzed to evaluate maximum degradation of OM in terms of rate constant ‘k’ (d-1) for each vessel as shown in Figure 3.
15
Figure 3: Degradation of organic matter with different composition and ‘k’ value for each vessel using Ky plot
16
From Figure 3, it can be inferred that Vessels 5, 7, 8, 9 and 10 containing 20% and more FA produced linear graphs in comparison to other vessels which contained no or less than 20% FA. Table 4: Organic matter loss (%) in different vessels during in-vessel composting process
V-1
46.411+0.011
57.330+0.3
63.117+0.017
68.148+0.15
73.290+0.46
Theoretical OM loss (%C) A 70.099
V-2
53.455+0.01
59.823+0.007
63.205+0.007
67.865+0.02
73.077+0.04
67.953
0.462
0.991
1.410
V-3
67.945+0.01
74.637+0.007
81.755+0.01
82.966+0.03
83.736+0.05
82.080
0.550
0.998
2.382
V-4
25.240+0.61
31.444+0.006
36.576+0.006
40.692+0.04
50.112+0.06
48.750
0.186
0.981
1.861
V-5
22.468+0.004
40.880+0.007
47.999+0.009
54.600+0.12
62.069+0.009
70.270
0.134
0.998
2.656
V-6
66.964+0.006
72.950+0.01
76.735+0.01
78.805+0.017
81.096+0.06
78.240
0.614
0.998
1.520
V-7
32.484+0.006
52.988+0.006
62.076+0.006
66.043+0.04
69.221+0.05
72.560
0.209
1.000
2.559
V-8
18.103+0.50
34.021+0.007
43.422+0.004
48.752+0.05
54.116+0.06
65.150
0.118
0.999
2.582
V-9
25.587+0.005
33.777+0.007
42.406+0.008
45.111+0.111
50.312+0.1
51.020
0.201
0.996
2.637
V-10
10.969+0.005
15.066+0.006
22.839+0.007
25.395+0.13
32.626+0.11
51.210
0.063
0.992
3.027
Vessel No.
OM loss (%) in 3 days (Mean + S.D)
OM loss (%) in 6 days
OM loss (%) in 9 days
OM loss (%) in 12 days
OM loss (%) in 15 days
(Mean + S.D)
(Mean + S.D)
(Mean + S.D)
(Mean + S.D)
k (d-1)
RMS
DurbinWatson ratio
0.322
0.994
1.652
The data presented in Table 4 divulges that value of (k) ranges between 0.100 d-1 and 0.650 d-1 for all the vessels. The addition of FA in in-vessel composting system significantly impacts the rate constant (k). From the plotted curves shown in Figure 3, it clearly indicated that in Vessels 1, 2, 3, 4, 6 and 7, maximum degradation of OM took place during initial five days and further the curves were found to be flat. The lowest value of k was observed for Vessel 10 and hence it was concluded that addition of FA with jaggery as an additive to the mixture of waste comprising 20% FA, 30% KW, 50% biomass and 5% jaggery tend to have least OM (%C) loss. From the t-test, it was observed that there was an insignificant difference between the data obtained from the Ky plot and the experimental observations.
17
4. Conclusion Substrate combination of 20% FA, 30% KW, 50% biomass and 5% jaggery contained C:N ratio (about 23:1), nitrogen (0.91%), sulphur (0.19%), phosphorus (0.86%) and potassium content (0.05%). The concentration of major heavy metals in the corresponding vessel was lower than other vessels. Hence, it is proposed to utilize these combinations to reduce bio-availability of heavy metals and enhance the soil productivity. External sources of P and K should be added to the finished compost. The modification of vessel model should be installed where the provision of leachate collection and aeration for removal of obnoxious gases from the system is required.
Acknowledgement The first author, Vivek Manyapu is thankful to the AcSIR for awarding Dr. A.P.J. Abdul Kalam fellowship to work at CSIR-NEERI, Nagpur.
18
5. References 1.
Abdel Salam, O.E., Reiad, N.A., ElShafei, M.M., 2011. A study of the removal characteristics of heavy metals from wastewater by low-cost adsorbents. J. Adv. Res. 2, 297–303. doi:10.1016/j.jare.2011.01.008
2.
Abdullah, N., Chin, N.L., 2010. Simplex-centroid mixture formulation for optimised composting of kitchen waste. Bioresour. Technol. 101, 8205-8210. doi:10.1016/j.biortech.2010.05.068
3.
Andersen, J.K., Boldrin, A., Christensen, T.H., Scheutz, C., 2011. Mass balances and life cycle inventory of home composting of organic waste. Waste Manag. 31, 1934–1942. doi:10.1016/j.wasman.2011.05.004
4.
APHA, 1998. Standard methods for The examination of water and wastewater, Twentith. ed. American Publc Health Association, American Water Works Association and Water Environemnt, Washington DC.
5.
Asija, A.K., Pareek, R.P., Singhania, R.A., Singh, S., 1984. Effect of Method of Preparation and Enrichment on the Quality of Manure. J. Indian Soc. Soil Sci. 32, 323–329.
6.
Asokan, P., Saxena, M., Asolekar, S.R., 2005. Coal combustion residues—environmental implications and recycling potentials. Resour. Conserv. Recycl. 43, 239–262. doi:10.1016/j.resconrec.2004.06.003
7.
Awasthi, S.K., Bhatnagar, J.P., 2000. Prevention of Food Adulteration Act (Act no. 37 of 1954) alongwith Central & State Rules (as amended for 1999), 3rd ed. /. ed. Ashoka Law House, New Delhi.
8.
Bernal, M,P., Navarro, A, F., Roig, A., Cegarra, J., Garcia, D., 1996. Carbon and nitrogen transformation during composting of sweet sorghum bagasse. Biol. Fertil. Soils 22, 141-148.
9.
Belyaeva, O.N., Haynes, R.J., 2009. Chemical, microbial and physical properties of manufactured soils produced by co-composting municipal green waste with coal fly ash. Bioresour. Technol. 100, 5203–5209. doi:10.1016/j.biortech.2009.05.032
10. Bhattacharyya, P., Chakrabarti, K., Chakraborty, A., 2005. Microbial biomass and enzyme activities in submerged rice soil amended with municipal solid waste compost and decomposed cow manure. Chemosphere 60, 310–318. doi:10.1016/j.chemosphere.2004.11.097 11. Bustamante, M.A., Paredes, C., Marhuenda-Egea, F.C., Pérez-Espinosa, A., Bernal, M.P., Moral, R., 2008. Co-composting of distillery wastes with animal manures: Carbon and nitrogen transformations in the evaluation of compost stability. Chemosphere 72, 551–557. doi:10.1016/j.chemosphere.2008.03.030 12. Central Electricity Authority, 2016. Executive summary power sector January-16 1–52. 13. Central Electricity Authority, 2015. Report On Fly Ash Generation At Coal/Lignite Based Thermal Power
19
Stations And Its Utilization In The Country For The Year 2014-15 1–50. 14. Central Public Health and Environment Engineering Organization (CPHEEO) Government of India, 2000. Manual on municipal solid waste management. New Delhi, India. 15. Cooperband, L., 2002. The Art and Science of Composting A resource for farmers and compost producers. Cent. Integr. Agric. Syst. 1–14. 16. Domínguez, J., Edwards, C.A., Subler, S., 1997. A Comparison of vermicomposting and composting. Biocycle. 57–59. 17. Fang, M., Wong, J.W.C., Li, G.X., Wong, M.H., 1998. Changes in biological parameters during cocomposting of sewage sludge and coal ash residues. Bioresour. Technol. 64, 55–61. doi:10.1016/S09608524(97)00156-9 18. Gabhane, J., William, S.P., Bidyadhar, R., Bhilawe, P., Anand, D., Vaidya, A.N., Wate, S.R., 2012. Additives aided composting of green waste: Effects on organic matter degradation, compost maturity, and quality of the finished compost. Bioresour. Technol. 114, 382–388. doi:10.1016/j.biortech.2012.02.040 19. Hagerty, D.J., Pavoni, J.L., Heer, J.E., 1973. Solid Waste Management ( Van Nostrand Reinhold Environmental Engineering Series ) By D . Joseph Hagerty. New York. 20. Hendriks, A.T.W.M., Zeeman, G., 2009. Pretreatments to enhance the digestibility of lignocellulosic biomass. Bioresour. Technol. 100, 10–18. doi:10.1016/j.biortech.2008.05.027 21. Hubbe, M.A., Nazhad, M., Sánchez, C., 2010. Composting as a way to convert cellulosic biomass and organic waste into high-value soil amendments: A review. Bioresour. Technol. 5, 2808–2854. doi:10.15376/biores.5.4.2808-2854 22. Jones, D.L., Healey, J.R., 2010. Organic amendments for remediation: Putting waste to good use. Elements. 6, 369–374. doi:10.2113/gselements.6.6.369 23. Korb, N., Jones, C., Jacobsen, J., 2005. Potassium Cycling, Testing, and Fertilizer Recommendations, in: Nutrient Management. Montana State University Publications, Bozeman, p. 12. 24. Kumar, S., 2011. Composting of municipal solid waste. Crit. Rev. Biotechnol. 31, 112–36. doi:10.3109/07388551.2010.492207 25. Kumar, S., Bhattacharyya, J.K., Vaidya, A.N., Chakrabarti, T., Devotta, S., Akolkar, A.B., 2009. Assessment of the status of municipal solid waste management in metro cities, state capitals, class I cities,
20
and class II towns in India: An insight. Waste Manage. 29, 883–895. doi:10.1016/j.wasman.2008.04.011 26. Liu, S., 2004. Analysis and measurement in papermaking industry. Beijing: Chemical Industry Press. 27. Lou, X.F., Nair, J., 2009. The impact of landfilling and composting on greenhouse gas emissions - A review. Bioresour. Technol. 100, 3792–3798. doi:10.1016/j.biortech.2008.12.006 28. Murphy, J.D., Power, N.M., 2006. A Technical, Economic and Environmental Comparison of Composting and Anaerobic Digestion of Biodegradable Municipal Waste. J. Environ. Sci. Heal. Part A 41, 865–879. doi:10.1080/10934520600614488 29. Paredes, C., Roig, A., Bernal, M.P., Sánchez-Monedero, M.A., Cegarra, J., 2000. Evolution of organic matter and nitrogen during co-composting of olive mill wastewater with solid organic wastes. Biol. Fertil. Soils 32, 222–227. doi:10.1007/s003740000239 30. Polprasert, C., 2007. Organic Waste Recycling - Technology and Management, Third. ed. IWA Publishing, Alliance House, 12 Caxton Street, London SW1H 0QS, UK, Bangkok. 31. Population Reference Bureau, 2017. World Population Data Sheet. PRB Publ. 1–22. 32. Rawoteea, S.A., Mudhoo, A., Kumar, S., 2017. Co-composting of vegetable wastes and carton: Effect of carton
composition
and
parameter
variations.
Bioresour.
Technol.
227,
171–178.
doi:10.1016/j.biortech.2016.12.019 33. Rihani, M., Malamis, D., Bihaoui, B., Etahiri, S., Loizidou, M., Assobhei, O., 2010. In-vessel treatment of urban
primary
sludge
by
aerobic
composting.
Bioresour.
Technol.
101,
5988–5995.
doi:10.1016/j.biortech.2010.03.007 34. Rynk, Robert, 1992. On-Farm Composting Handbook. Monogr. Soc. Res. Child Dev. 77, 132. doi:10.1111/j.1540-5834.2012.00684.x 35. Said-Pullicino, D., Erriquens, F.G., Gigliotti, G., 2007. Changes in the chemical characteristics of waterextractable organic matter during composting and their influence on compost stability and maturity. Bioresour. Technol. 98, 1822–1831. doi:10.1016/j.biortech.2006.06.018 36. Singh, J., 2013. Manufacturing Jaggery, a Product of Sugarcane, As Health Food. Agrotechnology 1, 10– 12. doi:10.4172/2168-9881.S11-007 37. Singh, S., Ram, L.C., Masto, R.E., Verma, S.K., 2011. A comparative evaluation of minerals and trace elements in the ashes from lignite, coal refuse, and biomass fired power plants. Int. J. Coal Geol. 87, 112–
21
120. doi:10.1016/j.coal.2011.05.006 38. Singh, Y., Sidhu, H.S., 2014. Management of cereal crop residues for sustainable rice-wheat production system in the Indo-Gangetic Plains of India. Proc. Indian Natl. Sci. Acad. 80, 95–114. doi:10.16943/ptinsa/2014/v80i1/55089 39. Sundberg, C., Smårs, S. and Jönsson, H., 2004. Low pH as an inhibiting factor in the transition from mesophilic to thermophilic phase in composting. Bioresour. Technol. 95(2), 145-150. 40. Smårs, S., Gustafsson, L., Beck-Friis, B. and Jönsson, H., 2002. Improvement of the composting time for household waste during an initial low pH phase by mesophilic temperature control. Bioresour. Technol. 84(3), pp.237-241. 41. U.S. EPA, 2009. Backyard composting it’s only natural. GreenScapes EPA530-F-0, 1–2. 42. U.S. EPA, 2000. Biosolids Technology Fact Sheet In-Vessel Composting of Biosolids. U.S. EPA, Washington, D.C. EPA 832-F-, 1–9. 43. Wang, S., 2008. Application of Solid Ash Based Catalysts in Heterogeneous Catalysis. Environ. Sci. Technol. 42, 7055–7063. doi:10.1021/es801312m 44. Wong, J.W.C., Fung, S.O., Selvam, A., 2009. Coal fly ash and lime addition enhances the rate and efficiency of decomposition of food waste during composting. Bioresour. Technol. 100, 3324–3331. doi:10.1016/j.biortech.2009.01.063 45. Wong, J.W.C., Li, S.W.Y., M.H., W., 1995. Coal fly ash as a composting material for sewage sludge: Effects on microbial activities. Environ. Technol. 16, 527–537. doi:10.1080/09593331608616294 46. Wong, M.H., Wong, J.W.C., 1986. Effects of Fly Ash on Soil Microbial Activity. Environ. Pollut. 40, 127– 144. 47. Wu, L., Ma, L.Q., Martinez, G. a., 2000. Comparison of Methods for Evaluating Stability and Maturity of Biosolids Compost. J. Environ. Qual. 29, 424. doi:10.2134/jeq2000.00472425002900020008x 48. Yao, Z.T., Ji, X.S., Sarker, P.K., Tang, J.H., Ge, L.Q., Xia, M.S., Xi, Y.Q., 2015. A comprehensive review on the applications of coal fly ash. Earth-Science Rev. 141, 105–121. doi:10.1016/j.earscirev.2014.11.016
22
List of Figures Figure 1: Variation of pH in different vessels Figure 2: Variation of temperature in different vessels Figure 3: Degradation of organic matter with different composition and ‘k’ value for each vessel using Ky plot
List of Tables Table 1: Distribution of substrates in different vessels Table 2: Comparison of physico-chemical characteristics of substrates Table 3: Comparison of physico-chemical parameters in different vessels after maturity Table 4: Organic matter loss (%) in different vessels during in-vessel composting process
23
Graphical abstract
24
Highlights:
Novel approach identified for management of coal fly ash and biomass wastes
Fly ash reduces the bioavailability of heavy metals to the plants
Trichoderma viride, T. harzianum and T. reesei consortia were used for composting
Jaggery as additive enhances microbial process and reduces the period of composting
25
S0960-8524(17)32174-0 https://doi.org/10.1016/j.biortech.2017.12.039 BITE 19294
To appear in:
Bioresource Technology
Received Date: Revised Date: Accepted Date:
14 November 2017 12 December 2017 13 December 2017
Please cite this article as: Manyapu, V., Mandpe, A., Kumar, S., Synergistic effect of fly ash in in-vessel composting of biomass and kitchen waste, Bioresource Technology (2017), doi: https://doi.org/10.1016/j.biortech.2017.12.039
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
SYNERGISTIC EFFECT OF FLY ASH IN IN-VESSEL COMPOSTING OF BIOMASS AND KITCHEN WASTE Vivek Manyapua, Ashootosh Mandpeb and Sunil Kumar*b a
Dr. A.P.J. Abdul Kalam fellow, Amity School of Earth and Environmental Sciences, Amity University Haryana, Gurgaon 122 413, India b
CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur 440 020, India *Corresponding author (Email): [email protected]
Abstract The present study aims to utilize coal fly ash for its property to adsorb heavy metals and thus reducing the bioavailability of the metals for plant uptake. Fly ash was incorporated into the invessel composting system along with organic waste. The in-vessel composting experiments were conducted in ten plastic vessels of 15 L capacity comprising varying proportions of biomass waste, kitchen waste and fly ash. In this study, maximum degradation of organic matter was observed in Vessel 3 having k value of 0.550 d-1. In vessel 10, 20% fly ash with a combination of 50% biomass waste and 30% kitchen waste along with the addition of 5% jaggery as an additive produced the best outcome with least organic matter (%C) loss and lowest value of rate constant (k). Keywords: Organic waste; in-vessel composting; fly ash; heavy metals; bioavailability
1
1. Introduction The global scale production of organic waste i.e., 100-300 kg person-1 year-1 (Jones and Healey, 2010) is proportional to the upsurging population of more than 7.5 billion (Population Reference Bureau, 2017). The agricultural production is rapidly intensified on the same piece of
land to fulfill the growing demands of food for such a huge population. This is done by the over-dosed application of chemical fertilizers and pesticides which strangle the soil to the apocalypse by releasing heavy metals into the soil. The soils in India are degrading at an alarming rate and to deal with this situation, attempts should be made for enrichment of soils with essential nutrients by using eco-friendly techniques. The compostable waste from municipal solid waste (MSW) accounts for about 39-54% in most of the cities of India (Kumar et al., 2009). More than 620 million tonnes (MT) of agricultural waste is generated in India every year (Singh and Sidhu, 2014). The huge amount of organic waste produced can be potentially utilized for agriculture to make the dying soils to be filled with life by nutrients enriched eco-friendly compost. There will be a reduction of 50-60% waste if it is converted into compost and thus will save the space used for landfilling and also emission of greenhouse gases (GHGs) can be prevented (Lou and Nair, 2009). The compost not only refills nutrients in the degrading soils but also lessens the huge burden of biomass waste from MSW, which is generated at the rate of 46.8 MT every year (Kumar, 2011). It is the compost which leads in the race among all other methods of organic waste management that include anaerobic digestion, landfilling and incineration, since it is easier to take up and manage (US EPA, 2009), economically being cheap (Murphy and Power, 2006), producing eco-friendly by-products and less GHGs emissions (Andersen et al., 2011). The
2
acceptable C:N ratio of combined feedstock can be 20:1 to 40:1 and ideal level can be 25:135:1. Acceptable Moisture Content (MC) can be 40-65% by weight, ideal being 45-60% (Rynk, 1992). The kitchen waste (KW) comprising 33.33% vegetable scraps, 33.33% fish waste and 33.33% newspaper gives satisfactory limits of MC about 59% and C/N ratio about 24.2 (Abdullah and Chin, 2010). Available oxygen >5% can be acceptable and ≥10% as ideal. Feedstock particle size <1 inch is acceptable. pH must be acceptable between 5.5-9 and ideal between 6.5-8 (Rynk, 1992). According to Central Public Health and Environment Engineering Organization (CPHEEO), Government of India, 2000, each of the NPK content should be >1% and the nitrate form of nitrogen should be present for regular uptake by plants. Compost maturity and stability can be confirmed by considering the respiration activity of the compost and its property of phytotoxicity (Wu et al., 2000). There are several types of composting methods for producing high-quality compost out of which four general methods adopted are windrow method, aerated static pile, vermicomposting and in-vessel composting (Cooperband, 2002; US EPA, 2000). Most of them are found to be sluggish. Since there is a highly alarming situation to eradicate the profuse biomass waste generated and also to replenish the dying soils, rapid composting systems need to be brought into the frame. Among the rapid composting systems, in-vessel system is one of the efficient compost producing methods. The in-vessel composting system is confined to a concrete tank, a metal/plastic vessel or container. There are variety of in-vessel methods vary with types of vessels used, turning mechanisms and aeration devices. With this system, one can control the composting process (Domínguez et al., 1997; US EPA, 2000). To rapidify the process of composting, additives can
3
be used. Among different additives used in composting process, jaggery showed best results (Gabhane et al., 2012). Among different energy sources, thermal energy is the main source of power in most parts of India contributing to 70% of the total generating capacity of India. Coal fly ash (FA) is one amongst the notorious byproducts produced during combustion of coal in thermal power stations (TPS) which is extremely stubborn to get eliminated from the ecosystem, causing environmental hazards, water and soil pollutions and ruination of ecological cycles (Yao et al., 2015). In India, out of 176.74 MT of FA generated by 151 TPSs, 107.77 MT is utilized for various purposes. During the lapse from 1996-97 to 2015-16, there was an increase of 6 folds in the utilization pecrcentage of FA, i.e. from 10% to 60.97% (Central Electricity Authority, 2016). Thus, in order to reduce the hazards and hindrances caused by this malignant matter, several types of research have been made to extract something good out of it. Worldwide, only 25% of the total FA generated is put into use (Wang, 2008). At present FA is put into potential applications viz. for soil amelioration, construction of roads, making bricks, synthesizing zeolite and as filler in polymers (Abdel Salam et al., 2011). It can also be used for heavy metal extraction, treatment of waste water for creating cenospheres (Asokan et al., 2005). Lime can be replaced by this noble powder because of its peculiar mechanisms that can reduce the bioavailability of heavy metals through physical adsorption and precipitate at high pH (Wong et al., 2009). Due to the presence of MgO and CaO, heavy metals get precipitated after adding coal FA to any compost or soil. Thus, reducing the heavy metal toxicity to plants grown in FA amended compost/soil (Wong et al., 1995). In the district of Nagpur, two prominent thermal power stations are located at Khapadkhera and Koradi with an installed capacity of 500 and 1100 Megawatts (MW), 4
respectively. Khaparkheda TPS generates 0.98 MT of FA and it utilizes 2.465% only. Koradi TPS generates 0.63 MT of FA and utilizes appreciable amount of FA (58.72%) (Central Electricity Authority, 2015). It was proved that co-composting FA with sewage sludge showed beneficial results (Fang et al., 1998). Furthermore, incorporating FA with the compost garnishes essential nutrients like silica, calcium oxide, alumina, magnesium oxide, iron oxide, potassium oxide, sodium oxide and sulphate (Singh et al., 2011). The nutrient values of FA get amassed with the compost without affecting the biological activity. If there is a high amount of FA amendments then it will pose hindrance in respiration of microbes (Wong and Wong, 1986). Though coal manifest is considered to be the most useful source of energy but the pollution caused due to the release of obnoxious gases by burning and the ashes produced create malignant havoc in the ecosystem producing hindrances in the natural flow of ecological cycles. Hence, a study was undertaken with an objective to investigate the effects of FA on different parameters (temperature, moisture, pH, C:N ratio, NPK content, heavy metal concentration and TC) with compost made out of brown waste (BW), green waste (GW) and KW in different proportions along with jaggery as an additive.
2. Materials and Methods 2.1. Sample Collection: Different BWs like dry leaves and branches were collected from tree shedding in the gardens of CSIR-NEERI, Nagpur. KW was collected from canteen of CSIRNEERI campus. GW comprising grass cuttings was collected from lawns after mowing. Coal FA was sampled out from Khaparkheda which is the coal-based TPS.
5
2.2. Substrate Analysis: The physical and chemical characteristics like pH (1:5 w/v waste:water) was measured by AQUASOL digital probe pH meter, MC (Gravimetric method); TC, TN, C:N ratio and Sulphur (Elementar Vario EL CHNS Analyser); Nitrate, Sulphate, Phosphate
(UV-1650pc, UV-VIS Spectrophotometer SHIMADZU); Cellulose and
Hemicellulose (Liu, 2004); Lignin (Klason’s method), COD (APHA, 1998), Heavy metal (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) concentration (ICP-OES, iCAP 6000 SERIES) of each substrate were analyzed. 2.3. Pre-treatment: All the substrates were shredded into 0.5-1 inches smaller pieces for increasing the surface area and porosity of substrate and ease the agitation process (Belyaeva and Haynes, 2009; Hendriks and Zeeman, 2009; Rawoteea et al., 2017; Rihani et al., 2010). They were then subjected to steam treatment to break down the high lignocellulose content. 2.4. Experimental Set-up: The experiment of in-vessel composting was conducted in ten plastic vessels of 15 L capacity each. Each vessel had a height of 32.5 cm. The top and base diameters being 28 cm and 23.6 cm, respectively. The vessels were having 20 small holes drilled at the base, aided with perforated rubber pipe internally to allow aeration through the 4 LPM (litres per minute) aerating pump. The ground substrates were made to form a mixture according to the proportions allotted and were loaded in the composting vessels along with microbial mixture, supplemented with additive presented in Table 1. 50 ml of a microbial mixture consisting of Trichoderma viride, T. harzianum and T. reesei was added in each vessel.
6
Table 1: Distribution of substrates in different vessels Vessels V-1 V-2 V-3 V-4 V-5 V-6 V-7 V-8 V-9 V-10
BW(g) 875 875 787.5 700 612.5 787.5 700 612.5 437.5 437.5
GW(g) 125 125 112.5 100 87.5 112.5 100 87.5 62.5 62.5
KW(g) X X X X X X X X 300 300
FA(g) X X 100 200 300 100 200 300 200 200
Additive (g) X 150 X X X 150 100 50 X 50
Microbial Mixture (ml) 50 50 50 50 50 50 50 50 50 50
In all the vessels, BW and GW were loaded in 7:1 ratio. Vessel 1 was loaded with BW and GW only. In Vessel 2, 15% jaggery as an additive was added along with ingredients of Vessel 1. Vessels 3, 4 and 5 contained 10%, 15% and 30% FA, respectively incorporated with BW and GW. Vessels 6, 7 and 8 contained 15%, 10% and 5% additive, respectively with same ingredients as in Vessels 3, 4 and 5. Vessel 9 contained 30% KW and 20% FA in addition to BW and GW. Vessel 10 contained an additive of 5% in addition to ingredients of Vessel 9. Total volatile solids (TVS) were determined as sample weight loss (previously ovendried at 105 oC) by muffling at 550 oC for 24 h (Said-Pullicino et al., 2007). Loss of OM was calculated using the initial (X1) and final (X2) ash contents according to the equation 1 (Paredes et al., 2000 and Bustamante et al., 2008). OM loss (%) = 100-100
………………………………(1)
2.5 Statistical analysis: Data referring to the OM losses produced throughout the composting process was fitted to a kinetic function by the Quasi-Newton algorithm. The algorithm estimated values of model parameters by minimizing the sum of squared differences between the experimental and calculated values with non-linear optimization using a Ky plot software to calculate the value of k. A first-order kinetic model was used for OM degradation during
7
composting (Bernal et al., 1996). This model was chosen as the best fit because it gave a randomized distribution of the residuals together with the lowest residual mean square (RMS) value (equation 2). OM loss (%) = A (1- e – kt) ……………………………………… (2) Where, A is the maximum degradation of OM (%C), k the rate constant (d-1) and t the composting time (d).
3. Results and Discussion 3.1. Physico-chemical characteristics of the substrates The physico-chemical characteristics of FA, BW, GW and KW used as feedstock in the composting process are presented in Table 2. The FA was having a neutral pH and would not hamper the composting process. KW had high moisture content (82.5%) which would be a good source of moisture for microbes. FA contained a very negligible amount of cellulose but its high hemicellulose and lignin content made it extremely resistant to degrade. KW had least lignin content as it contained cooked material. C:N ratio of the three substrates BW, GW and KW was found to be 19.62, 22.71 and 20.99, respectively which is optimal for composting but FA had very low C:N ratio of 1.79. Since FA was used in smaller proportion, its C:N ratio was neglected. It was of great concern to assay heavy metals because FA was being incorporated in the compost. Although the concentration of heavy metals was less than the permissible limits but Fe content was found to be higher in comparison to other elements.
8
Table 2: Comparison of physico-chemical characteristics of substrates
Sl. No.
Parameters
FA (Mean + S.D.)
BW (Mean + S.D.)
GW (Mean + S.D.)
KW (Mean + S.D.)
1
pH
6.95+0.05
5.94+0.04
5.19+0.03
5.48+0.05
2
MC %
0.17+0.02
45.96+0.48
60.25+0.5
82.50+0.4
3
Cellulose %
2+0.04
38+0.42
9+0.1
54+0.6
4
Hemicellulose %
94.5+0.8
30+0.5
85.5+0.4
64.5+0.23
5
Lignin %
88.75+0.61
41.5+0.3
41.25+0.5
31.75+0.45
-1
6
Nitrate (mg g )
0.02+0.01
15.25+0.24
55.74+0.4
62.08+0.3
7
Phosphate (mg g-1)
0.09+0.005
1.86+0.05
20.3+0.5
19.26+0.05
-1
8
Sulphate (mg g )
5.65+0.07
110.68+0.2
37.68+0.04
2.54+0.04
9
TC %
0.27+0.03
19.18+0.08
37.43+0.08
43.47+0.11
10
TN %
0.04+0.05
0.98+0.07
1.65+0.04
2.07+0.04
11
C:N
1.79+0.04
19.62+0.04
22.71+0.06
20.99+0.06
12
S%
0.02+0.003
0.08+0.005
0.14+0.008
0.13+0.07
13
Heavy metals (mg kg-1)
FA
BW
GW
KW
Indian permissible limits (Awasthi and Bhatnagar, 2000)
a)
Cd
0.24+0.005
BDL
BDL
BDL
3-6
b)
Co
4.06+0.06
0.05+0.006
3.08+0.06
0.06+0.008
n/a
c)
Cr
16.39+0.06
3.92+0.04
10.97+0.15
5.49+0.06
n/a
d)
Cu
14.49+0.06
6.33+0.05
11.29+0.06
4.82+0.05
135-270
e)
Fe
4,993.7+0.50
357.42+0.40
4,217.1+0.60
340.16+0.10
n/a
f)
Mn
92.39+0.39
12.44+0.4
78.25+0.3
11.07+0.09
n/a
g)
Ni
11.97+0.05
1.03+0.003
8.09+0.06
1.04+0.05
75-150
h)
Pb
4.15+0.05
1.92+0.04
2.80+0.15
1.41+0.02
250-500
i)
Zn
40.23+0.3
40.44+0.4
38.82+0.4
31.04+0.5
300-600
BDL - Below Detection Limit; n/a – data not available
3.2. Operational indices Measurement of pH and temperature was done thrice a day with the interval of four hours at 10:00, 14:00 and 18:00 hours, respectively and the average value was calculated. The values of mean and standard deviation are presented in Tables 2 through 4. Samples from each 9
vessel were assessed by drying at 105 oC for 24 hrs and OM was determined by the loss on ignition at 550o C (APHA, 1998) with an interval of three days from the beginning of the experiment. 3.3. Physico-chemical characteristics of the compost 3.3.1. Odour, Colour and Texture Except Vessels 9 and 10, all other vessels had an earthy odour. Vessels 9 and 10 had a little decaying odour due to the moisture which was present even after maturation. The KW was found to be responsible for high moisture content. Vessels 1 and 4 had a brown colour, while Vessels 2 and 3 had dark brownish colour. Vessel 5 to 10 had greyish appearance due to the presence of FA. FA was also present in Vessels 3 and 4 but was overcome by BW. Vessels 9 and 10 were soggy in texture while all others were having soil like texture (after sieving). 3.3.2. Volume reduction More than 60% volume reduction was observed in all Vessels, except Vessels 5 and 8 due to the presence of high amount of FA. 3.3.3. C:N Ratio C: N ratio is a very vital factor which decides the microbial activity for composting process. The carbon and nitrogen are used as an energy source and building the cell structure. If nitrogen content is less, it can be used up completely and the microbes will be devoid of nitrogen and some of them might die (Polprasert, 2007). Other organisms might act upon the stored nitrogen for building up their cell material. Thus, the carbon content is reduced to a significant level while recycling nitrogen. High C:N ratio will result in exploitation of nitrogen
10
from the soil, while low C:N ratio will have no effect in improvement of soil structure (Bhattacharyya et al., 2005). In vessels 1, 2 and 5, the C:N ratio was more than 25 while in all others it was found to be less than 25 and the least was found in vessel 10. 3.3.4. Potassium Vessels 2, 6 and 10 contained very high potassium content in comparison to others since they contained jaggery. Jaggery itself contains 1056 mg of potassium per 100 g (Singh, 2013). Potassium is an easily leachable element (Korb et al., 2005). This is the reason for potassium content which was less than 1% as recommended by Central Public Health and Environment Engineering Organization (CPHEEO) Government of India, 2000, for an ideal compost. 3.3.5. Phosphorus Vessel 10 had highest phosphorus (P) content due to the presence of FA and KW with jaggery. Also, vessels 2 and 6 had a good content of P due to high jaggery content. At the end of composting, the P content was increased in all the cases. The phosphorus is immobilized due to microbial action and also the water solubility of P reduced due to humification (Asija et al., 1984). 3.3.6. pH There was a pH drop at the initial stage in all the cases which was due to the formation of organic acids (Hagerty et al., 1973). Later, the pH moved to neutral because the organic acids got converted into CO2 and later the pH attained constancy. These typical changes in pH could be seen in Vessels 7 and 10 (Figure 1). The lag phase observed in the vessel 7 is caused
11
by the formation of organic acids (Sundberg, 2004). This might be due to the rise in temperature caused by improper ventilation (Smârs, 2002).
Figure 1: Variation of pH in different vessels
3.3.7. Temperature Due to microbial decomposition process, there was an initial rise in temperature (Figure 2). Later the temperature declined and became stable because of decreased microbial activity which resulted due to reduced levels organic matter (Hagerty et al., 1973). Only vessel 10 could attain the stability in temperature. In all other vessels, temperature varied. In Vessel 7, an abrupt increase in temperature was observed due to exaggerated microbial activity and later a fall in temperature was also seen.
12
Figure 2: Variation of temperature in different vessels
3.3.8. Heavy metals Arsenic could only be detected in FA (15.4 mg kg-1). Except for Vessel 1, all other vessels contained a high amount of iron content due to the presence of FA as substrate. All other heavy metals were below than the permissible limits (Awasthi and Bhatnagar, 2000). Vessel 10 contained a lower concentration of most of the heavy metals in comparison to others as presented in Table 3. The least concentration of the maximum heavy metals could be found in vessel 1 since it did not contain FA. There was a drastic loss of Arsenic and Tin. Other heavy metals had a significant accumulation in all the vessels due to the presence of FA. It can be inferred that the increase in heavy metal concentration was due to the partial decomposition of the substrate added in the in-vessel composting system.
13
Table 3: Comparison of physico-chemical parameters in different vessels after maturity
Sl. No .
Parame ters
V-1 (Mean + S.D)
V-2 (Mean + S.D)
1
TC(%)
32.09+0.5
29.40+0.4
2
TN(%)
1.15+0.03
1.09+0.01
3
C:N
27.90+0.6
26.97+0.3
4
S (%)
0.06+0.02
0.16+0.00 1
5
P (%)
6
K (%)
0.58+0.00 6 0.04+0.00 1
V-4 (Mean + S.D) 21.79+0.4 7 0.88+0.00 5
0.05+0.00 1
V-3 (Mean + S.D) 26.36+0 .36 1.08+0. 01 24.41+0 .41 0.15+0. 002 0.29+0. 002 0.02+0. 001
0.70+0.02
24.76+0.3 0.11+0.00 2 0.22+0.00 2 0.02+0.00 7
7 a)
As
b)
Cd
c)
Co
d)
Cr
e)
Cu
f)
Fe
g)
Mn
h)
Ni
i)
V-5 V-6 (Mean (Mean + S.D) + S.D) 13.87+0 20.59+0 .2 .3 0.53+0. 0.93+0. 005 005 26.17+0 22.14+0 .4 .5 0.08+0. 0.14+0. 005 002 0.18+0. 0.66+0. 006 005 0.02+0. 0.04+0. 001 001 Heavy Metals
V-7 (Mean + S.D) 16.11+0. 11 0.71+0.0 05 22.69+0. 6 0.12+0.0 02 0.07+0.0 02 0.03+0.0 01
V-8 (Mean + S.D)
V-9 (Mean + S.D)
V-10 (Mean + S.D)
17.17+0.2
25.51+0.4
20.54+0.4
0.72+0.00 5
1.05+0.05
0.91+0.005
23.85+0.6
24.30+0.4
22.57+0.43
0.13+0.00 3 0.06+0.00 2 0.02+0.00 1
0.15+0.00 4 0.05+0.00 1 0.03+0.00 1
0.19+0.005 0.86+0.004 0.05+0.001
15.37+0.3 7 0.19+0.00 5
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
BDL
0.21+0.00 4
0.11+0.00 3
0.18+0.00 4
0.11+0.005
8.93+0.5
7.96+0.4
9.75+0.45
8.18+0.45
43.67+0. 33 46.05+0. 29
35.33+0.3 7 40.37+0.3 7
45.71+0.5
42.47+0.44
70.41+0.4 3
0.20+0. 005 9.88+0. 4 48.39+0 .8 55.95+0 .43
0.12+0.00 4
9.15+0.07
0.14+0. 004 8.25+0. 45 47.91+0 .6 43.38+0 .35
0.15+0.006
6.76+0.06
0.26+0. 008 12.33+0 .3 82.32+0 .70 64.99+0 .4
50.70+0.3 5
39.44+0.4
9513+0.3 15
13244+0. 332
15598+ 0.628
10080+0. 793
12139+. 733
13404+ 0.402
12347+0 .429
11554+0.4 5
12765+0. 274
10828+0.72
295.95+0. 135 16.92+0.0 6
351.86+0. 284% 20.71+0.0 6
302.47+0. 33 15.27+0.0 5
5.97+0.03
4.94+0.05
4.88+0.05
j)
Se
BDL
BDL
Sn
5.14+0.08
5.01+0.02
4.95+0.02
l)
Zn
BDL 17.00+0.3 4 111.55+0. 08
BDL
k)
BDL 49.48+0.5 2 98.82+0.0 6
300.77+ 0.997 23.60+0. 05 6.27+0.0 4 BDL 6.09+0.1 7 83.70+0. 07
284.48+0.70 2
8.85+0.05
327.01+ 0.917 25.29+0 .06 10.56+0 .06 BDL 6.44+0. 22 83.92+0 .05
318.76+0. 595 23.49+0.0 6
6.64+0.03
293.44+ 0.68 24.30+0 .07 7.00+0. 06 BDL 8.13+0. 12 67.97+0 .04
282.59+0. 424 19.48+0.0 6
Pb
405.60+ 0.493 37.96+0 .06 8.09+0. 06 BDL 10.68+0 .36 111.34+ 0.08
72.51+0.0 5
84.76+0.0 4
63.92+0.06
30.23+0.4 8 49.42+0.4 2
35.39+0.5
6.81+0.3 24.54+0.5 38.77+0.4
6.70+0.04 BDL 10.54+0.4 4 73.50+0.0 8
22.03+0.05
BDL-Below Detection Limit
3.3.9. Organic matter (OM) Evaluation of changes in OM content was used to characterize the different phases of composting as well as the relative completion of the composting process (Hubbe et al., 2010).
14
The data was analyzed to evaluate maximum degradation of OM in terms of rate constant ‘k’ (d-1) for each vessel as shown in Figure 3.
15
Figure 3: Degradation of organic matter with different composition and ‘k’ value for each vessel using Ky plot
16
From Figure 3, it can be inferred that Vessels 5, 7, 8, 9 and 10 containing 20% and more FA produced linear graphs in comparison to other vessels which contained no or less than 20% FA. Table 4: Organic matter loss (%) in different vessels during in-vessel composting process
V-1
46.411+0.011
57.330+0.3
63.117+0.017
68.148+0.15
73.290+0.46
Theoretical OM loss (%C) A 70.099
V-2
53.455+0.01
59.823+0.007
63.205+0.007
67.865+0.02
73.077+0.04
67.953
0.462
0.991
1.410
V-3
67.945+0.01
74.637+0.007
81.755+0.01
82.966+0.03
83.736+0.05
82.080
0.550
0.998
2.382
V-4
25.240+0.61
31.444+0.006
36.576+0.006
40.692+0.04
50.112+0.06
48.750
0.186
0.981
1.861
V-5
22.468+0.004
40.880+0.007
47.999+0.009
54.600+0.12
62.069+0.009
70.270
0.134
0.998
2.656
V-6
66.964+0.006
72.950+0.01
76.735+0.01
78.805+0.017
81.096+0.06
78.240
0.614
0.998
1.520
V-7
32.484+0.006
52.988+0.006
62.076+0.006
66.043+0.04
69.221+0.05
72.560
0.209
1.000
2.559
V-8
18.103+0.50
34.021+0.007
43.422+0.004
48.752+0.05
54.116+0.06
65.150
0.118
0.999
2.582
V-9
25.587+0.005
33.777+0.007
42.406+0.008
45.111+0.111
50.312+0.1
51.020
0.201
0.996
2.637
V-10
10.969+0.005
15.066+0.006
22.839+0.007
25.395+0.13
32.626+0.11
51.210
0.063
0.992
3.027
Vessel No.
OM loss (%) in 3 days (Mean + S.D)
OM loss (%) in 6 days
OM loss (%) in 9 days
OM loss (%) in 12 days
OM loss (%) in 15 days
(Mean + S.D)
(Mean + S.D)
(Mean + S.D)
(Mean + S.D)
k (d-1)
RMS
DurbinWatson ratio
0.322
0.994
1.652
The data presented in Table 4 divulges that value of (k) ranges between 0.100 d-1 and 0.650 d-1 for all the vessels. The addition of FA in in-vessel composting system significantly impacts the rate constant (k). From the plotted curves shown in Figure 3, it clearly indicated that in Vessels 1, 2, 3, 4, 6 and 7, maximum degradation of OM took place during initial five days and further the curves were found to be flat. The lowest value of k was observed for Vessel 10 and hence it was concluded that addition of FA with jaggery as an additive to the mixture of waste comprising 20% FA, 30% KW, 50% biomass and 5% jaggery tend to have least OM (%C) loss. From the t-test, it was observed that there was an insignificant difference between the data obtained from the Ky plot and the experimental observations.
17
4. Conclusion Substrate combination of 20% FA, 30% KW, 50% biomass and 5% jaggery contained C:N ratio (about 23:1), nitrogen (0.91%), sulphur (0.19%), phosphorus (0.86%) and potassium content (0.05%). The concentration of major heavy metals in the corresponding vessel was lower than other vessels. Hence, it is proposed to utilize these combinations to reduce bio-availability of heavy metals and enhance the soil productivity. External sources of P and K should be added to the finished compost. The modification of vessel model should be installed where the provision of leachate collection and aeration for removal of obnoxious gases from the system is required.
Acknowledgement The first author, Vivek Manyapu is thankful to the AcSIR for awarding Dr. A.P.J. Abdul Kalam fellowship to work at CSIR-NEERI, Nagpur.
18
5. References 1.
Abdel Salam, O.E., Reiad, N.A., ElShafei, M.M., 2011. A study of the removal characteristics of heavy metals from wastewater by low-cost adsorbents. J. Adv. Res. 2, 297–303. doi:10.1016/j.jare.2011.01.008
2.
Abdullah, N., Chin, N.L., 2010. Simplex-centroid mixture formulation for optimised composting of kitchen waste. Bioresour. Technol. 101, 8205-8210. doi:10.1016/j.biortech.2010.05.068
3.
Andersen, J.K., Boldrin, A., Christensen, T.H., Scheutz, C., 2011. Mass balances and life cycle inventory of home composting of organic waste. Waste Manag. 31, 1934–1942. doi:10.1016/j.wasman.2011.05.004
4.
APHA, 1998. Standard methods for The examination of water and wastewater, Twentith. ed. American Publc Health Association, American Water Works Association and Water Environemnt, Washington DC.
5.
Asija, A.K., Pareek, R.P., Singhania, R.A., Singh, S., 1984. Effect of Method of Preparation and Enrichment on the Quality of Manure. J. Indian Soc. Soil Sci. 32, 323–329.
6.
Asokan, P., Saxena, M., Asolekar, S.R., 2005. Coal combustion residues—environmental implications and recycling potentials. Resour. Conserv. Recycl. 43, 239–262. doi:10.1016/j.resconrec.2004.06.003
7.
Awasthi, S.K., Bhatnagar, J.P., 2000. Prevention of Food Adulteration Act (Act no. 37 of 1954) alongwith Central & State Rules (as amended for 1999), 3rd ed. /. ed. Ashoka Law House, New Delhi.
8.
Bernal, M,P., Navarro, A, F., Roig, A., Cegarra, J., Garcia, D., 1996. Carbon and nitrogen transformation during composting of sweet sorghum bagasse. Biol. Fertil. Soils 22, 141-148.
9.
Belyaeva, O.N., Haynes, R.J., 2009. Chemical, microbial and physical properties of manufactured soils produced by co-composting municipal green waste with coal fly ash. Bioresour. Technol. 100, 5203–5209. doi:10.1016/j.biortech.2009.05.032
10. Bhattacharyya, P., Chakrabarti, K., Chakraborty, A., 2005. Microbial biomass and enzyme activities in submerged rice soil amended with municipal solid waste compost and decomposed cow manure. Chemosphere 60, 310–318. doi:10.1016/j.chemosphere.2004.11.097 11. Bustamante, M.A., Paredes, C., Marhuenda-Egea, F.C., Pérez-Espinosa, A., Bernal, M.P., Moral, R., 2008. Co-composting of distillery wastes with animal manures: Carbon and nitrogen transformations in the evaluation of compost stability. Chemosphere 72, 551–557. doi:10.1016/j.chemosphere.2008.03.030 12. Central Electricity Authority, 2016. Executive summary power sector January-16 1–52. 13. Central Electricity Authority, 2015. Report On Fly Ash Generation At Coal/Lignite Based Thermal Power
19
Stations And Its Utilization In The Country For The Year 2014-15 1–50. 14. Central Public Health and Environment Engineering Organization (CPHEEO) Government of India, 2000. Manual on municipal solid waste management. New Delhi, India. 15. Cooperband, L., 2002. The Art and Science of Composting A resource for farmers and compost producers. Cent. Integr. Agric. Syst. 1–14. 16. Domínguez, J., Edwards, C.A., Subler, S., 1997. A Comparison of vermicomposting and composting. Biocycle. 57–59. 17. Fang, M., Wong, J.W.C., Li, G.X., Wong, M.H., 1998. Changes in biological parameters during cocomposting of sewage sludge and coal ash residues. Bioresour. Technol. 64, 55–61. doi:10.1016/S09608524(97)00156-9 18. Gabhane, J., William, S.P., Bidyadhar, R., Bhilawe, P., Anand, D., Vaidya, A.N., Wate, S.R., 2012. Additives aided composting of green waste: Effects on organic matter degradation, compost maturity, and quality of the finished compost. Bioresour. Technol. 114, 382–388. doi:10.1016/j.biortech.2012.02.040 19. Hagerty, D.J., Pavoni, J.L., Heer, J.E., 1973. Solid Waste Management ( Van Nostrand Reinhold Environmental Engineering Series ) By D . Joseph Hagerty. New York. 20. Hendriks, A.T.W.M., Zeeman, G., 2009. Pretreatments to enhance the digestibility of lignocellulosic biomass. Bioresour. Technol. 100, 10–18. doi:10.1016/j.biortech.2008.05.027 21. Hubbe, M.A., Nazhad, M., Sánchez, C., 2010. Composting as a way to convert cellulosic biomass and organic waste into high-value soil amendments: A review. Bioresour. Technol. 5, 2808–2854. doi:10.15376/biores.5.4.2808-2854 22. Jones, D.L., Healey, J.R., 2010. Organic amendments for remediation: Putting waste to good use. Elements. 6, 369–374. doi:10.2113/gselements.6.6.369 23. Korb, N., Jones, C., Jacobsen, J., 2005. Potassium Cycling, Testing, and Fertilizer Recommendations, in: Nutrient Management. Montana State University Publications, Bozeman, p. 12. 24. Kumar, S., 2011. Composting of municipal solid waste. Crit. Rev. Biotechnol. 31, 112–36. doi:10.3109/07388551.2010.492207 25. Kumar, S., Bhattacharyya, J.K., Vaidya, A.N., Chakrabarti, T., Devotta, S., Akolkar, A.B., 2009. Assessment of the status of municipal solid waste management in metro cities, state capitals, class I cities,
20
and class II towns in India: An insight. Waste Manage. 29, 883–895. doi:10.1016/j.wasman.2008.04.011 26. Liu, S., 2004. Analysis and measurement in papermaking industry. Beijing: Chemical Industry Press. 27. Lou, X.F., Nair, J., 2009. The impact of landfilling and composting on greenhouse gas emissions - A review. Bioresour. Technol. 100, 3792–3798. doi:10.1016/j.biortech.2008.12.006 28. Murphy, J.D., Power, N.M., 2006. A Technical, Economic and Environmental Comparison of Composting and Anaerobic Digestion of Biodegradable Municipal Waste. J. Environ. Sci. Heal. Part A 41, 865–879. doi:10.1080/10934520600614488 29. Paredes, C., Roig, A., Bernal, M.P., Sánchez-Monedero, M.A., Cegarra, J., 2000. Evolution of organic matter and nitrogen during co-composting of olive mill wastewater with solid organic wastes. Biol. Fertil. Soils 32, 222–227. doi:10.1007/s003740000239 30. Polprasert, C., 2007. Organic Waste Recycling - Technology and Management, Third. ed. IWA Publishing, Alliance House, 12 Caxton Street, London SW1H 0QS, UK, Bangkok. 31. Population Reference Bureau, 2017. World Population Data Sheet. PRB Publ. 1–22. 32. Rawoteea, S.A., Mudhoo, A., Kumar, S., 2017. Co-composting of vegetable wastes and carton: Effect of carton
composition
and
parameter
variations.
Bioresour.
Technol.
227,
171–178.
doi:10.1016/j.biortech.2016.12.019 33. Rihani, M., Malamis, D., Bihaoui, B., Etahiri, S., Loizidou, M., Assobhei, O., 2010. In-vessel treatment of urban
primary
sludge
by
aerobic
composting.
Bioresour.
Technol.
101,
5988–5995.
doi:10.1016/j.biortech.2010.03.007 34. Rynk, Robert, 1992. On-Farm Composting Handbook. Monogr. Soc. Res. Child Dev. 77, 132. doi:10.1111/j.1540-5834.2012.00684.x 35. Said-Pullicino, D., Erriquens, F.G., Gigliotti, G., 2007. Changes in the chemical characteristics of waterextractable organic matter during composting and their influence on compost stability and maturity. Bioresour. Technol. 98, 1822–1831. doi:10.1016/j.biortech.2006.06.018 36. Singh, J., 2013. Manufacturing Jaggery, a Product of Sugarcane, As Health Food. Agrotechnology 1, 10– 12. doi:10.4172/2168-9881.S11-007 37. Singh, S., Ram, L.C., Masto, R.E., Verma, S.K., 2011. A comparative evaluation of minerals and trace elements in the ashes from lignite, coal refuse, and biomass fired power plants. Int. J. Coal Geol. 87, 112–
21
120. doi:10.1016/j.coal.2011.05.006 38. Singh, Y., Sidhu, H.S., 2014. Management of cereal crop residues for sustainable rice-wheat production system in the Indo-Gangetic Plains of India. Proc. Indian Natl. Sci. Acad. 80, 95–114. doi:10.16943/ptinsa/2014/v80i1/55089 39. Sundberg, C., Smårs, S. and Jönsson, H., 2004. Low pH as an inhibiting factor in the transition from mesophilic to thermophilic phase in composting. Bioresour. Technol. 95(2), 145-150. 40. Smårs, S., Gustafsson, L., Beck-Friis, B. and Jönsson, H., 2002. Improvement of the composting time for household waste during an initial low pH phase by mesophilic temperature control. Bioresour. Technol. 84(3), pp.237-241. 41. U.S. EPA, 2009. Backyard composting it’s only natural. GreenScapes EPA530-F-0, 1–2. 42. U.S. EPA, 2000. Biosolids Technology Fact Sheet In-Vessel Composting of Biosolids. U.S. EPA, Washington, D.C. EPA 832-F-, 1–9. 43. Wang, S., 2008. Application of Solid Ash Based Catalysts in Heterogeneous Catalysis. Environ. Sci. Technol. 42, 7055–7063. doi:10.1021/es801312m 44. Wong, J.W.C., Fung, S.O., Selvam, A., 2009. Coal fly ash and lime addition enhances the rate and efficiency of decomposition of food waste during composting. Bioresour. Technol. 100, 3324–3331. doi:10.1016/j.biortech.2009.01.063 45. Wong, J.W.C., Li, S.W.Y., M.H., W., 1995. Coal fly ash as a composting material for sewage sludge: Effects on microbial activities. Environ. Technol. 16, 527–537. doi:10.1080/09593331608616294 46. Wong, M.H., Wong, J.W.C., 1986. Effects of Fly Ash on Soil Microbial Activity. Environ. Pollut. 40, 127– 144. 47. Wu, L., Ma, L.Q., Martinez, G. a., 2000. Comparison of Methods for Evaluating Stability and Maturity of Biosolids Compost. J. Environ. Qual. 29, 424. doi:10.2134/jeq2000.00472425002900020008x 48. Yao, Z.T., Ji, X.S., Sarker, P.K., Tang, J.H., Ge, L.Q., Xia, M.S., Xi, Y.Q., 2015. A comprehensive review on the applications of coal fly ash. Earth-Science Rev. 141, 105–121. doi:10.1016/j.earscirev.2014.11.016
22
List of Figures Figure 1: Variation of pH in different vessels Figure 2: Variation of temperature in different vessels Figure 3: Degradation of organic matter with different composition and ‘k’ value for each vessel using Ky plot
List of Tables Table 1: Distribution of substrates in different vessels Table 2: Comparison of physico-chemical characteristics of substrates Table 3: Comparison of physico-chemical parameters in different vessels after maturity Table 4: Organic matter loss (%) in different vessels during in-vessel composting process
23
Graphical abstract
24
Highlights:
Novel approach identified for management of coal fly ash and biomass wastes
Fly ash reduces the bioavailability of heavy metals to the plants
Trichoderma viride, T. harzianum and T. reesei consortia were used for composting
Jaggery as additive enhances microbial process and reduces the period of composting
25