Coupling Hydrothermal Treatment with Stripping Technology for Fast

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Coupling Hydrothermal Treatment with Stripping Technology for Fast Ammonia Release and Effective Nitrogen Recovery from Chicken Manure Weiwei Huang, Tian Yuan, Ziwen Zhao, Xi Yang, Wenli Huang, Zhenya Zhang, and Zhongfang Lei ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.6b00315 • Publication Date (Web): 25 May 2016 Downloaded from http://pubs.acs.org on June 5, 2016

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ACS Sustainable Chemistry & Engineering

Coupling Hydrothermal Treatment with Stripping Technology for Fast Ammonia Release and Effective Nitrogen Recovery from Chicken Manure Weiwei Huang,†,‡ Tian Yuan,†,‡ Ziwen Zhao,† Xi Yang,† Wenli Huang,§ Zhenya Zhang,*,† and Zhongfang Lei*,† †

Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai,

Tsukuba, Ibaraki 305-8572, Japan §

MOE Key Laboratory of Pollution Process and Environmental Criteria, College of

Environmental Science and Engineering, Nankai University, No. 94 Weijin Road, Nankai District, Tianjin 300071, China Corresponding Authors *Z. Zhang. Tel./fax: +81 298 534712. Email: [email protected]. *Z. Lei. Tel./fax: +81 298 5346703. Email: [email protected].

ACS Paragon Plus Environment

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ABSTRACT: In order to mitigate the environmental impacts associated with accelerated global N cycle, a hybrid pretreatment procedure combining hydrothermal treatment (HTT) with ammonia stripping was developed to effectively recover N as valuable ammonia product from chicken manure (CM). Processing of the CM at 180 °C for 30 min resulted in 208% increase in soluble organic carbon (SOC) and 46% conversion of organic-N to ammonia-N. Analysis of carbon mass balance revealed that carbohydrates, proteins and volatile fatty acids (VFAs) were the major contributors to SOC (~100%) in the processed CM under this HTT condition. Further prolongation of holding time to 60 min or increase of HTT temperature to 220 °C resulted in some increase in ammonia yield but obvious decrease in SOC concentration and possible formation of inhibitory or non-biodegradable products as well, compromising the practical value of the processed CM as feedstock for methane production. After ammonia recovery through a circulating stripping system coupled with acid absorption, methane production potentials of the resultant ammonia-stripped CM residue were assessed via 45 days’ anaerobic digestion trials. Results from this work reflected an overall N recovery efficiency of 57% from CM and increase in methane yield by 24% (compared to raw CM).

KEYWORDS: Ammonia stripping, Chicken manure, Hydrothermal pretreatment, Soluble organic products, Methane


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INTRODUCTION Ammonia that produced primarily through Baber-Bosch reaction is an important raw material in chemical industry. Also, it is regarded as a promising H2 energy carrier due to its high H density, CO2 free nature and easy long-distance transportation.1 Nevertheless, the fixation and application of massive amount of ammonia has disturbed and accelerated the global N cycle, leading to a wide range of environmental problems.2 The conflicts between environmental preservation and the need for development have propelled us to seek alternatives for ammonia production in a renewable and sustainable way. Animal manure represents one of the biggest anthropologic sources of N pollution. Traditionally, it has been disposed onto the farmlands to improve soil fertility. But in recent decades, this practice is handicapped by the availability of low cost chemical fertilizers. The N nutrients in animal manure are often not used to their potential, which poses a burden to the environment and leads to unbalance of N nutrients. Therefore, there is a clear demand for N recycling from the organic manure so that the environmental problems can be alleviated and the accelerated global N cycle can be halted. In this study, chicken manure (CM) typically with a high organic N content was selected as an example of animal manure. To achieve effective recovery of N from CM as ammonia, the primary step is to find an efficient method to disintegrate the organic-N. Recently, hydrothermal treatment (HTT) has been recognized as an appealing approach for organic solids degradation, with potential benefits of reclaiming various useful products like reducing sugars,3 volatile fatty acids (VFAs),4 phosphorus5,6 and energy.7-10 Although ammonia has been identified as the major mineral product from HTT degradation of N-containing compounds,11-14 its recovery is however


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not received much attention. A previous work11 on hydrothermal deamination of sewage sludge has identified three characteristic hydrothermal regimes: hydrolysis of labile protein and inorganic-N compounds below 300 °C, pyridine-N deamination at 340 °C and stable protein deamination at 380 °C. And a significant N reduction by 76.9% in the solid residue was observed at 380 °C.11 Despite the efficient ammonia release at this high temperature, the cost for heating and device setup remains a challenge. An alternative is thus directed toward the degradation of organic-N at milder HTT temperatures ≤ 220 °C, within which range labile organic-N can be partially destructed without intensive formation of polycyclic aromatic hydrocarbons or pyridineN restricting the ammonia release efficiency and compromise digestibility of the CM residues.9,10,15,16 However, no systematic and elaborate information can be found on either the mechanisms of ammonia release at this temperature range or the dynamic interactions between ammonia release and organic-C solubilization. Thus an elaborated understanding of the conversion from organic-N to ammonia is prerequisite for optimization of the HTT process to achieve high and economical ammonia release efficiency and maximum utilization of the solid residue for energy production. The produced ammonia can be recovered by stripping technology, an effective process that can be applied for ammonia recovery from dry anaerobic digested swine manure as proven recently by Huang et al..17 The HTT processed and ammonia-stripped CM residue can serve as ideal feedstock for anaerobic digestion (AD). The objective of this work was to find out the proper HTT conditions to achieve fast and efficient ammonia release from CM. To make full use of CM, attention was also paid to accumulation of other useful organic products including soluble proteins, carbohydrates, and VFAs. More specifically, during HTT process the effects of temperature and holding time on organic solids solubilization and ammonia release were elucidated. Furthermore, the potential of


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ammonia-stripped CM for methane (CH4) production was tested via AD trials after ammonia being recovered by a circulating stripping system developed in the lab.

MATERIALS AND METHODS Raw materials. Raw chicken manure (RCM) was collected from a local farm (Ibaraki, Japan) and stored at 4 °C before use. Mesophilic anaerobic sludge was sampled from a wastewater treatment plant in Ibaraki, Japan, and used within 24 hours. The sludge was concentrated by centrifugation at 7300 g for 10 min and used as seed sludge for CH4 fermentation after the supernatant being discarded. Characteristics of the raw materials are listed in Table 1.

Table 1. Characteristics of Raw Chicken Manure and Anaerobic Sludge Used in the Experiments general property

unit

raw chicken manure (RCM)

anaerobic sludge (seed sludge)

Total solids (TS, wet weight based)

%

41.99 (±1.40)

5.31 (±0.13)

Volatile solids (VS, wet weight based)

%

24.53 (±0.78)

4.06 (±0.11)

Total ammonia nitrogen (TAN)

mg/g-VS

10.15 (±0.53)

6.97 (±0.16)

Total nitrogen (TN)

mg/g-VS

34.23 (±1.70)

64.45 (±3.17)

Total Kjeldahl nitrogen (TKN)

mg/g-VS

33.55 (±1.79)

62.18 (±2.31)

Total organic nitrogen (TON)a

mg/g-VS

23.40

55.21

pH

-

6.08 (±0.14)

7.28 (±0.17)

C/N

-

9.30 (±0.13)

5.84 (±0.10)

Note: pH of RCM was determined in the diluted manure samples with TS content of 25%. The data are expressed as mean (±SD) values of five tests. a

TON = TKN - TAN.


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Hydrothermal Treatment Experiments. The HTT experiments were performed in a 200 ml enclosed stainless steel reactor equipped with a cylindrical electric heater and an internal temperature sensor (OM Lab-tech MMJ-200, Japan). Temperatures were maintained within 6 °C of set conditions. Agitation was realized by a motor-driven propeller throughout the experiments. 130 g mixture of RCM and deionized water was loaded into the reactor with total solids (TS) content being adjusted to around 25% according to the preliminary trials. A total of 12 HTT conditions were tested and each condition was repeated three times. Under constant agitation rate of 100 rpm, the reactor was heated up to preset temperature (140 °C, 180 °C or 220 °C), and then the reactor was maintained at this temperature for a designated time duration (0, 15, 30 or 60 min). At the end of HTT experiment, the heater was powered off and the reactor was cooled with a fan to room temperature (around 25 °C) before further analysis. Figure S1 (Supplementary Information) illustrates the temperature change in the reactor under different HTT conditions. The reactor temperature was elevated at an average rate of 14.4, 12.1 and 11.4 °C/min during the heating process when the designated temperature was 140, 180 and 220 °C, respectively. Holding time was defined in this work as the elapsed time from the moment when the reactor first reached the preset temperature to that when the cooling started. The corresponding pressures at 140 °C, 180 °C and 220 °C were 0.3 MPa, 1.0 MPa and 2.7 MPa, respectively. Ammonia Recovery. Ammonia stripping from the HTT processed CM was carried out in an enclosed and circulating system as described in a previous work.17 The experimental stripping set-up consisted of a set of 500 ml containers. 100 g pretreated CM (wet weight) was loaded into the stripping bottle equipped with stirring device, and headspace of the system was flushed with N2 to maintain an anaerobic environment. The gas was firstly humidified by the water containing bottle, and then purged through the manure containing bottle placed in waterbath at a gas flow


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rate of 170 ml/min. The escaped ammonia was absorbed by 1.5 M HCl solution. This stripping system has been previously tested to be successful for ammonia recovery from fermented swine manure at 20% TS.17 Based on the previous results, ammonia stripping from the HTT processed CM was conducted at initial pH 11.0 (adjusted with Ca(OH)2) and 55 °C for 3 hours in this study. Methane Fermentation. For CH4 fermentation, the test fermenter, a 500 ml glass bottle, was loaded with 80 g of RCM (adjusted with deionized water to 25% TS) or the ammonia-stripped CM together with 150 g seed sludge and 170 g deionized water. Meanwhile, the control reactor was loaded with the same amount of seed sludge and added with deionized water to achieve a final volume of 400 ml. System pH was adjusted to around 7.0 with 1.5 M HCl solution. After thoroughly mixing, the bottles were then sealed with rubber stoppers, flushed with N2 and incubated at 35 °C in an incubator. Each fermentation experiment was conducted in duplicate. The CH4 production potential of CM, presented as ml (CH4) per gram of CM volatile solids (ml/g-CMVS), was corrected by subtracting the CH4 yield obtained from the control reactors. Analytical Methods. The flowchart of sample analysis during HTT experiments is illustrated in Scheme S1 (Supplementary Information). After the reactor being cooled down to room temperature, the headspace gas was released and collected by a gas sampling bag (Tedlar bag, Asone). Then the collected gas was scrubbed by HCl solutions (1.5 M, 500 ml × 2) in a sealed and circulating stripping system for 35 min at a gas flow rate of 170 ml/min to guarantee complete capture of the gaseous ammonia. The stripping system (scrubbing bottles, tubes and gas pump) was flushed with N2 before the experiment. Finally, carbon dioxide (CO2) content in the acid-scrubbed gas was analyzed by a Shimadzu GC-8A/TCD packed with a Porapak Q


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column and the gas volume was quantified by water displacement. The whole procedure was conducted in a sealed environment. For solid samples analysis, the HTT processed CM was collected carefully and weighted for total weight loss. Contents of TS and volatile solids (VS) were determined before and after the HTT experiments. The TS was determined as the constant dry matters (DM) remained in the manure samples after drying at 105 °C for 24 hours, and VS was calculated as the loss of DM after burning at 600 °C for 3 hours. Contents of organic C, H and N in the DM were determined by an organic elemental analyzer (Perkin-Elmer 2004 CHN, USA). Manure pH was measured directly using a semi-solid pH meter (Testo 206, Germany). For analysis of total nitrogen (TN) and total Kjeldahl nitrogen (TKN), the solid manure was diluted and mixed by known amount of deionized water and then measured in accordance with standard methods.18 Total organic nitrogen (TON) was calculated as the difference between TKN and total ammonia nitrogen (TAN). As indicated in Scheme S1, samples for measurement of soluble products were prepared by diluting 4 g manure (wet weight) with 40 ml deionized water. The resultant mixture was then centrifuged at 7300 g for 20 min and then the resultant supernatant was filtered through 0.45 µm membrane (PTFE, Membrane Solutions, US). Ammonia-N in the filtrate was determined according to standard methods.18 Concentration of TAN in the HTT processed CM was recorded as the sum of ammonia-N detected in the filtrate and the amount that escaped from the reactor and absorbed by the scrubbing solutions. Concentrations of VFAs were determined via Shimadzu GC-14B/FID equipped with Unisole F-200 30/60 column (Japan). Soluble organic carbon (SOC) was analyzed by a TOC analyzer (Shimadzu TOC-VCSN, Japan). Carbohydrates


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and proteins were measured with phenol-sulfuric method19 and Coomassie brilliant blue method,20 respectively. Biogas production was measured and calculated according to readings on the scale of syringes connected to the fermentation bottles. The content of CH4 was determined by Shimadzu GC-8A (Japan). Calculation. Reduction in TS (%) or VS (%) after the CM being hydrothermally treated was defined as follows: TS reduction (%) = VS reduction (%) =

[Initial TS] - [Final TS] [Initial TS]

×100

[Initial VS] - [Final VS] [Initial VS]

×100

(1) (2)

To study the decomposition efficiency of organic-N to ammonia-N, N mass balance was also analyzed. In this study, TAN yield (mg/g-VS) was defined as the net increase of TAN in CM after HTT (i.e. [Final TAN]-[Initial TAN]). And N recovery efficiency was calculated according to equation (3). TAN release (mg)

N recovery efficiency (%) = Loss of organic-N (mg) ×100

(3)

in which TAN release (mg) = [TAN yield] (mg/g-VS) × VS (g), and the loss of organic-N is the difference of organic-N in CM samples before and after HTT. Conversion ratio of TON to TAN (%), final TAN/TKN ratio (%), and volumetric TAN yield (g/L) defined respectively by equations (4), (5) and (6) were used in this study to compare the performance of ammonia release from manure wastes through different treatment methods. [TAN yield]

Conversion ratio of TON to TAN (%) = [Initial TON] ×100 [Final TAN]

(4)

Final TAN/TKN ratio (%) = [Final TKN] ×100

(5)

Volumetric TAN yield (g/L) = [TAN yield] × [VSconc. ]

(6)


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where VSconc. is in g/L. Statistical Analysis. For each HTT condition, three replicates were conducted, and the determination of related parameters was duplicated. All the results are expressed as mean values of six repetitions. For each fermentation experiment, the CH4 yield was calculated according to the results obtained from the two parallel fermentation trials. The analysis of statistics and correlation coefficients was performed by using SPSS statistics 19.0 (IBM, Armonk, NY, USA). Significance was assumed at p < 0.05.

RESULTS AND DISCUSSION Reduction of TS and VS after HTT. Figure 1 indicates the reductions in TS and VS after HTT. The TS and VS contents of CM decreased in all scenarios. An increase in temperature apparently resulted in accelerated disintegration of organic substances, contributing to higher TS and VS reduction efficiencies in the processed CM. The greatest levels of reduction in both TS and VS were observed at 220 °C. Figure 1 also shows that longer treatment duration favored the solids dissolution to some extent, especially at 220 °C during the initial 15 min. After HTT at 220 °C for 0 - 60 min, the reductions in TS and VS varied between 17.64% - 24.65% and 25.36% - 28.77%, respectively. In all tested scenarios, increased temperature rather than prolonged holding time seemed to exert greater influence on TS and VS reductions.


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35

TS reduction (%) VS reduction (%)

30

Reduction efficiency (%)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


25 20 15 10 5 0

0

15

30

60

0

15

30

60

0

15

30

60

Holding time (min) 140

180

Treatment temperature (°C)

220

Figure 1. Reductions in total solids (TS) and volatile solids (VS) after hydrothermal treatment (HTT) process. Solubilization of Solid Organics during HTT. As shown in Figure 2a, after HTT at 140 °C for 0 - 60 min, the soluble proteins in the processed CM remained relatively stable with variations in concentration less than 20% compared to RCM. However, it was remarkably accumulated to 137.33 mg/g-VS as HTT temperature increased to 180 °C (for holding 15 min), while significantly decreased to 25.33 mg/g-VS when HTT was conducted at 220 °C for holding 60 min. After HTT at 180 °C for 0 - 60 min, the concentration of carbohydrates was increased by about 200% - 600% in relative to RCM. The highest level of carbohydrates was recorded as 416.08 mg/g-VS after HTT at 180 °C for 30 min. It was observed that prolongation of reaction time to 60 min or further increasing HTT temperature to 220 °C led to a dramatic decline of carbohydrates concentration, similarly as the trend detected in proteins concentration.


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Compared to the changes of carbohydrates and proteins, the total volatile fatty acids (TVFAs) remained relatively stable in the processed CM at each HTT temperature when this pretreatment process lasted for 0 - 60 min (Figure 2b). More VFAs was found to accumulate during HTT at 220 °C, and acetic acid (HAc) was the dominant component in all trials (> 80%). Interestingly, HAc was the sole VFAs component in all HTT processed CM samples at 140 °C and in RCM, and propionic acid (HPr) was detectable when HTT was carried out at 180 °C for holding longer than 15 min or at 220 °C. The concentrations of n-butyric acid (n-HBu) and iso-valeric acid (isoHVa) were found to be much less, about 1.73 mg/g-VS and 1.10 mg/g-VS only after HTT at 220°C for holding 30 min and 60 min, respectively.

(a) Soluble proteins or carbohydrates (mg/g-VS)

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500

Carbohydrates Proteins 400

300

200

100

0

RCM

0 15 30 60

0 15 30 60

0 15 30 60

Holding time (min)

140

180


220


12

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(b) 40 Iso-valerate Butyrate Propionate Acetate

VFAs (mg/g-VS)

30

20

10

0

RCM

0 15 30 60

0 15 30 60

0 15 30 60


140


220

(c) 300 SOC and its major contributors (mg/g-VS)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


250

TVFAs-C Proteins-C Carbohydrates-C SOC

200

150

100

50

0

RCM

0 15 30 60

0 15 30 60

0 15 30 60


180


220


13


(d) 80

CO2 production (ml/g-VS)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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60

40

20

1 0

0

15 30 60 140

0

15 30 60

Holding time (min)

0

15 30 60

180


220

Figure 2. Profiles of (a) soluble proteins and carbohydrates, (b) volatile fatty acids (VFAs) including acetic acid (HAc), propionic acid (HPr), n-butyric acid (n-HBu) and iso-valeric acid (iso-HVa), (c) soluble organic carbon (SOC) and its major contributors in the treated chicken manure, and (d) CO2 production during HTT.

Concentrations of SOC in the raw and the processed CM samples are depicted in Figure 2c. Obviously, the SOC increased in all the treated samples in comparison to RCM. Temperature had a profound influence on SOC. An increase in HTT temperature from 140 °C to 180 °C favored the dissolution of carbonaceous organics from CM. Further increase in temperature from 180 °C to 220 °C, however, resulted in decreased SOC most probably due to the breakdown of soluble organic matters into gaseous or mineralization products. Holding time also influenced the concentration of SOC to some extent, especially at 180 °C. The highest SOC level, 243.11 mg/gVS, was detected in the CM samples treated at 180 °C for 30 min, while the SOC concentration


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was found to decrease to 211.30 mg/g-VS when holding time was prolonged to 60 min at this temperature. In order to study the percentage distribution of carbohydrates-C, proteins-C, and TVFAs-C in SOC, carbon mass balance was also analyzed in this work as illustrated in Figure 2c. The C content of proteins was estimated based on a theoretical formula (C4H6.1O1.2N),21 while that of carbohydrates was based on glucose (C6H12O6). In addition, the calculation of TVFA-C was based on the individual VFA. As shown, the smallest differences, 0.9% and 1.4% between the measured SOC and calculated organic-C in terms of soluble proteins, soluble carbohydrates and TVFAs, were obtained from the samples treated at 180 °C for 15 and 30 min, respectively, apparently indicating that carbohydrates-C, proteins-C and TVFAs-C were the major components of soluble organics in the processed CM under these two HTT conditions. Larger gap found between the measured SOC and calculated organic-C at higher temperature of 220 °C was probably attributable to the generation of smaller molecular weight organic compounds (e.g. amino acids, lactic acids, alcohols, etc.)14,15 or melanoidins16 occurred during the hydrolysis step of HTT or through the reaction between carbohydrates and amino groups coexisting in the CM. Further characterization and identification of the produced organics are necessary for shedding light on this complicated HTT process. Gaseous Products during HTT. Gas analysis confirmed the formation of CO2 in the headspace of HTT reactor as shown in Figure 2d. An increase in both temperature and holding time favored the generation of CO2, which occurred primarily via decarboxylation7 and was identified as the predominant C-source gas at HTT temperatures ≤ 220 °C.8 As noticed, the generation of CO2 was negligible at 140 °C, while it started to evolve quickly and increased along with the duration of HTT process at 180 °C. When HTT was conducted at 220 °C, the


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evolution of CO2 became remarkably evident, ranging between 53.78 - 61.52 ml/g-VS when this pretreatment lasted for 0 - 60 min. The CO2 evolution under HTT at 220°C was to some extent in agreement with the decrease in SOC concentration (Figure 2c). Changes in Ammonia Concentration and System pH. Figure 3a depicts the effects of different HTT conditions on pH variation and TAN release from the CM. As shown, increase in both temperature and holding time was favorable for TAN release (except HTT at 220 °C for 0 60 min). The production of TAN reached a maximum of 22.85 mg/g-VS after HTT at 180 °C for 60 min, corresponding to a TON conversion ratio of 54.4%. Further increase in temperature to 220 °C led to insignificant increase in TAN concentration (p = 0.544 > 0.05) although further reduction in TS or VS was observed at 220 °C (Figure 1). Three reasons might be accountable for this phenomenon. Firstly, uric acids with a high N content (approximately 33%, calculated based on its formula, C5H4N4O3) and low molecular weight could undergo thermal breakdown to form ammonia easily at 140 °C and 180 °C, while intense decomposition of macromolecular proteins with typically lower N content of about 16% according to its theoretical formula (C4H6.1O1.2N)n21 usually occurs at higher temperatures. Secondly, the majority of labile organicN in CM could be degraded at temperatures lower than 220 °C while thermal destruction of the single amino acids formed or the rest of the stable proteins may require higher activation energy.11 In addition, hydrothermal decomposition of organic-N to form ammonia might be limited at 220 °C due to the polymerization of amino groups into melanoidins whereas great weight loss of organic CM was observed as the temperature increased from 180°C to 220 °C (Figure 1). Given the complexity of hydrothermal reactions and chemical components in CM, further investigation on the dynamic interactions between various factors is necessary to make clear the mechanisms underlying this phenomenon.


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The fraction of gaseous ammonia-N entrapped by the scrubbing solution is demonstrated in Figure 3b. Clearly, although an increasing trend was detected in the gaseous ammonia-N with the increase in HTT temperature and holding time, the amount was negligible when compared to TAN (Figure 3a). The manure pH varied most probably as a result of the dynamic interaction between ammonia release and organic acids production. During HTT at 140 °C, fast ammonia release led to increased system pH from 6.08 to 7.17 - 7.41. When more pronounced accumulation of organic acids (e.g. VFAs, etc.) occurred at 180 °C and 220 °C (Figure 2b), the system pH was detected to decline to be around or even below 7.00.

(a) 45

8

TAN

pH

40 7 35 6

*

30

NS NS NS

25

5

NS

20

NS

pH

TAN (mg/g-VS)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


4

15 3

10 5

RCM

0 15 30 60

0 15 30 60

0 15 30 60

2


180

220



17


(b) 0.20 Gaseous ammonia-N (mg/g-VS)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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0.15

0.10

0.05

0.00

0

15 30 60 140

0

15 30 60

Holding time (min)

0

15 30 60

180


220

Figure 3. Effects of hydrothermal treatment (HTT) on (a) total ammonia nitrogen (TAN) release and pH variation (where NS indicates no significant difference, *p < 0.05 according to Duncan’s multiple range tests), and (b) the production of gaseous ammonia-N. Organic-N Decomposition and N Mass Balance. The variations of organic C, H and N contents in the solid fraction of raw and processed CM were investigated and presented in Figure 4 in terms of H/N ratio and C/N ratio. As shown, both H/N and C/N ratios decreased in all the treated CM in comparison to RCM. On the whole, an increase in temperature led to higher mineralization efficiency of organic-H and organic-C than organic-N in the CM. This observation might be brought about by the following reasons: (1) the condensation of amino groups through Maillard reaction may restrict organic-N mineralization; (2) accelerated decarboxylation of the organic matters in CM at increasing HTT temperatures; and (3) higher temperatures above certain level might be prerequisite for the cleavage of stable proteins remaining in the particulate substances (CM in this study).11


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Besides the effects of temperature and holding time on organic-N mineralization during the HTT process, other factors like raw material compositions, system pH, water content and coexisting ionic compounds including phosphorus, magnesium, calcium, etc. might also contribute to the retardation of ammonia-N release at higher temperatures in this study. The synergetic effects of these multiple factors on ammonia production during HTT of CM are also necessary for future investigation. Table S1 (Supplementary Information) summarizes the N mass balance analysis under four typical HTT conditions: (1) HTT at 180 °C for holding 15 min (HTT180-15), (2) HTT at 180 °C for holding 30 min (HTT180-30), (3) HTT at 180°C for holding 60 min (HTT180-60), and (4) HTT at 220 °C for holding 0 min (HTT220-0). During the HTT process, the DM content decreased mainly because of the formation of water and gaseous products. High N recovery efficiencies in the range of 82.40% to 89.02% were achieved under the four typical scenarios, signaling that ammonia-N was the main product during the mineralization of organic-N when HTT process was performed at 180 - 220 °C. Increasing holding time from 30 to 60 min at 180 °C led to little increase in TAN concentration (p = 0.069 > 0.05) but undesirable decline of soluble proteins and carbohydrates concentration by 38.5% and 26.0%, respectively, compromising subsequent utilization of the CM residues. Considering the energy consumption associated with temperature and reaction time, energy efficiency for ammonia release, and accumulation of useful organic products for their possible reclamation or boosting CH4 fermentation, the optimum HTT operational conditions in this study were determined to be 180 °C for holding 30 min.


19


12.0

2.5

10.0

1.5

8.0

0.5

6.0

-0.5

4.0

RCM

0 15 30 60

0 15 30 60

0 15 30 60

Ratio of H/N

C/N H/N

Ratio of C/N

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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-1.5


180

220


Figure 4. Changes in ratios of organic C/N and H/N in the solid residue of hydrothermal processed chicken manure.


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Table 2. Comparison of Ammonia Release Efficiencies Obtained through Different Treatment Methods TON conversion to TANa

initial substrate characteristics treatment method

operation conditions

manure

TS (%)

VS (%)

TKN (mg/gVS)

TON (mg/gVS)

Ratio (%)

TAN/TKN (%)

volumetric TAN yield (g/L)

references

Hydrothermal

180 °C for 15 min

Chicken

25.0

14.6

33.55

23.40

42.2

59.7

1.44

This work

Hydrothermal

180 °C for 30 min

Chicken

25.0

14.6

33.55

23.40

46.4

62.6

1.59

This work

Hydrothermal

220 °C for 0 min

Chicken

25.0

14.6

33.55

23.40

58.3

70.9

1.99

This work

Thermo-alkaline

120 °C for 30 min, 0.07g/g-TS NaOH

Dairy

6.7

5.8

33.77

27.61

12.1

28.1

0.20

22

Thermo-alkaline

120 °C for 30 min, 0.07g/g-TS CaO

Dairy

6.7

5.8

33.77

27.61

13.1

28.9

0.21

22

Thermo-acidic

120 °C for 30 min, 2% (V/V) H2SO4

Dairy

6.7

5.8

33.77

27.61

17.1

32.2

0.28

22

Thermo-acidic

120 °C for 30 min, 0.74% (V/V) HCl

Dairy

6.7

5.8

33.77

27.61

16.6

31.8

0.27

22

Ultrasonication

specific energy input: 500 kJ/kg-TS

Hog

9.3

6.7

247.46

142.69

9.8

48.0

0.94

23

Anaerobic digestion

65 °C for 8 days at initial pH 8.5

Chicken

24.5

14.1

141.7

124.7

20.9

30.4

3.67

24

Anaerobic digestion

55 °C for 8 days at initial pH 10.0

Swine

20.0

15.5

29.8

19.3

57.3

72.5

1.71

25

a

The data presented in the table were calculated according to the information provided in the related references.

TS-total solids, VS-volatile solids, TKN-total Kjeldahl nitrogen, TON-total organic nitrogen, TAN-total ammonia nitrogen.


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Comparative Study on Ammonia Production and Correlation Analysis Between Different Tested Parameters. Table 2 lists the performances of different treatment methods on ammonia release from manure wastes. Among these treatment methods, HTT is an advantageous option owing to its effectiveness, no need of chemicals addition, relatively short reaction time and low water requirement. Temperature is a crucial factor governing the extent to which TON conversion can proceed. As seen from Table 2, high TS content CM (25% TS in this study) can be processed in HTT systems, yielding higher volumetric TAN production with smaller reactor volume. Table S2 (Supplementary Information) displays the result of correlation analysis between the tested parameters after HTT of CM under the 12 designed conditions. As indicated, the final TAN concentration in the processed CM had significantly positive correlations with TS and VS reduction, VFAs production, and CO2 generation (p < 0.01), implying that ammonia-N is generated concomitantly with the destruction of solid organic matters into smaller molecular weight compounds. Ammonia Recovery from HTT Processed CM by Stripping. Ammonia stripping was carried out with the four processed CM samples: HTT180-15, HTT180-30, HTT180-60 and HTT220-0 due to their relatively higher TAN yields (Figure 3a and Table 2). After 3 hours of stripping in the circulating system, the ammonia-N removal efficiencies of the four samples mentioned above were detected to be 95.6%, 96.2%, 95.4% and 96.6%, respectively, in agreement with the ammonia stripping efficiency when this system was applied for dry anaerobic digested swine manure.17 Quantification of ammonia-N in HCl solutions demonstrates that more than 96% of the removed ammonia-N from CM can be efficiently entrapped in the circulating system. After 3


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hours’ stripping, no significant increase of SOC was observed in all the scrubbing solutions (p = 0.0613 > 0.05). Except a trace amount of acetic acid, neither carbohydrates nor proteins was detected. Ammonia stripping at high TS content avoided the foaming problems, preventing the contamination of acid solutions from organic substances. In addition, the obtained NH4Cl solutions can be used for fertilizers production or serve other industrial purposes. Methane Fermentation Trials by Using the Ammonia-stripped HTT Processed CM. The CH4 production potentials of RCM and ammonia-stripped CM residues (HTT180-15, HTT18030, HTT180-60 and HTT220-0) were assessed via 45 days’ AD trials. The initial AD conditions were listed in Table S3 (Supplementary Information). Results (Figure S2, Supplementary Information) show that after CM being processed at 180 °C for 15, 30 and 60 min, CH4 evolution started earlier and CH4 yields were recorded respectively at 186.18, 195.53 and 158.55 ml/gCMVS after 45 days’ AD in comparison to 157.17 ml/g-CMVS from RCM (without HTT and ammonia stripping). After 45 days’ AD, the concentration of ammonia-N in the RCM reactor was 1290.02 mg/L, whereas lower ammonia-N concentrations of 722.11, 708.23, 714.54 and 710.75 mg/L were detected in the AD reactors of HTT180-15, HTT180-30, HTT180-60 and HTT220-0, respectively. In addition to the immediate availability of fermentable and soluble organic substances, much lower levels of ammonia-N in the pretreated CM residues might be attributable to their high CH4 yields. Therefore, the enhancement effect is expected to be greater when AD for CH4 production is conducted under dry conditions after CM samples being HTT processed and ammonia-stripped. On the other hand, a remarkably low CH4 yield of 21.82 ml/g-CMVS was obtained from HTT220-0 during the same period when CM was pretreated at 220 °C for 0 min and ammoniastripped. Ammonia toxicity was unlikely to be the reason for digestion failure in this reactor


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since similar ammonia-N concentrations were detected in the four digesters loaded with HTT processed CM samples. Instead, the formation of some inhibitory or non-degradable compounds (like melanoidins) during HTT at this temperature might be accountable.9 Adaptation of methanogens to these inhibitory substances might be necessary if being used for CH4 production. Environmental Implications. The large amount of CM generated each year globally represents a source of N pollution that requires proper disposal. Traditional practice of AD followed by spreading of the digestate onto farmland has some shortcomings such as low CH4 yield and insufficient breakdown of the organic manure, mainly due to ammonia toxicity and high transportation cost when there is not enough arable land nearby and difficulties in retention of N nutrient during storage and spreading. In addition, high level of volatile ammonia in the biogas is a problem of concern.26 Therefore, effective N removal and recovery from the manure wastes prior to CH4 fermentation is crucial for controlling ammonia inhibition, promoting CH4based C capture and mitigating the environmental impacts associated with NOx and greenhouse gases emissions. The hybrid procedure of HTT followed by solid-state ammonia stripping exhibits good performance in organic-N decomposition and N recovery from CM as valuable ammonia products, achieving not only an overall TN recovery efficiency of 57% but also the alleviation of environmental pollutions associated with increasing input of active N. As for further implementation of effective ammonia production and recovery from manure wastes, investigations are underway so as to accelerate ammonia production from HTT process and improve ammonia-N removal and recovery from the processed manure.

ASSOCIATED CONTENT


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Supporting Information The Supporting Information including Table S1-S3, Scheme S1 and Figure S1-S2 are available free of charge via the Internet at http://pubs.acs.org.

AUTHOR INFORMATION Corresponding Authors *Z. Zhang. Tel./fax: +81 298 534712. Email: [email protected]. *Z. Lei. Tel./fax: +81 298 536703. Email: [email protected]. Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. ‡Weiwei Huang and ‡Tian Yuan contributed equally. Notes The authors declare no competing financial interest.

ACKNOWLEDGMENTS This work was supported by JSPS KAKENHI Grant Numbers 25281046, 15K00599, and 15K12235. REFERENCES


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(1) Miura, D.; Tezuka, T. A comparative study of ammonia energy systems as a future energy carrier, with particular reference to vehicle use in Japan. Energy 2014, 68, 428-436. (2) Vitousek, P.M.; Aber, J.D.; Howarth, R.W.; Likens, G.E.; Matson, P.A.; Schindler, D.W.; Schlesinger, W.H.; Tilman, D. Human alteration of the global nitrogen cycle: sources and consequences. Ecol. Appl. 1997, 7, 737-750. (3) Lin, R.; Cheng, J.; Ding L.; Song, W.; Qi, F.; Zhou, J.; Cen, K. Subcritical water hydrolysis of rice straw for reducing sugar production with focus on degradation by-products and kinetic analysis. Bioresource Technol. 2015, 186, 8-14. (4) Yin, J.; Wang, K.; Yang, Y.; Shen, D.; Wang, M.; Mo H. Improving production of volatile fatty acids from food waste fermentation by hydrothermal pretreatment. Bioresource Technol. 2014, 171, 323-329. (5) Heilmann, S.M.; Molde, J.S.; Timler, J.G.; Wood, B.M.; Mikula, A.L.; Vozhdayev, G.V.; Colosky, E.C.; Spokas, K.A.; Valentas, K.J. Phosphorus Reclamation through Hydrothermal Carbonization of Animal Manures. Environ. Sci. Technol. 2014, 48, 10323-10329. (6) Qian, T.-T.; Jiang, H. Migration of Phosphorus in Sewage Sludge during Different Thermal Treatment Processes. ACS Sustainable Chem. Eng. 2014, 2, 1411-1419. (7) Berge, N.D.; Ro, K.S.; Mao, J.; Flora, J.R.V.; Chappell, M.A.; Bae, S. Hydrothermal carbonization of municipal waste streams. Environ. Sci. Technol. 2011, 45, 5696-5703. (8) Yu, G.; Zhang, Y.; Schideman, L.; Funk, T.; Wang, Z. Distributions of carbon and nitrogen in the products from hydrothermal liquefaction of low-lipid microalgae. Energ. Environ. Sci. 2011, 4, 4587-4595.


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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(9) Bougrier, C.; Delgenès, J.P.; Carrère, H. Effects of thermal treatments on five different waste activated sludge samples solubilisation, physical properties and anaerobic digestion. Chem. Eng. J. 2008, 139, 236-244. (10) Carrère, H.; Sialve, B.; Bernet, N. Improving pig manure conversion into biogas by thermal and thermo-chemical pretreatments. Bioresource Technol. 2009, 100, 3690-3694. (11) He, C.; Wang, K.; Yang, Y.; Amaniampong, P.N.; Wang, J.Y. Effective nitrogen removal and recovery from dewatered sewage sludge using a novel integrated system of accelerated hydrothermal deamination and air stripping. Environ. Sci. Technol. 2015, 49, 6872-6880. (12) Oliviero, L.; Barbier, J.; Duprez, Jr. D. Wet Air Oxidation of nitrogen-containing organic compounds and ammonia in aqueous media. Appl. Catal. B. 2003, 40, 163-184. (13) Oulego, P.; Laca, A.; Diaz, M. Kinetics and Pathways of Cyanide Degradation at High Temperatures and Pressures. Environ. Sci. Technol. 2013, 47, 1542-1549. (14) Sato, N.; Quitain, A.T.; Kang, K.; Daimon, H.; Fujie, K. Reaction kinetics of amino acid decomposition in high-temperature and high-pressure water. Ind. Eng. Chem. Res. 2004, 43, 3217-3222. (15) Wilson, C.A.; Novak, J.T. Hydrolysis of macromolecular components of primary and secondary wastewater sludge by thermal hydrolytic pretreatment. Water Res. 2009, 43, 44894498. (16) Dwyer, J.; Starrenburg, D.; Tait, S.; Barr, K.; Batstone, D.J.; Lant, P. Decreasing activated sludge thermal hydrolysis temperature reduces product colour, without decreasing degradability. Water Res. 2008, 42, 4699-4709.


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(17) Huang, W.; Huang, W.; Yuan, T.; Zhao, Z.; Cai, W.; Zhang, Z.; Lei, Z.; Feng, C. Volatile fatty acids (VFAs) production from swine manure through short-term dry anaerobic digestion and its separation from nitrogen and phosphorus resources in the digestate. Water Res. 2016, 90, 344-353. (18) APHA (American Public Health Association). Standard Methods for the Examination of Water and Wastewater; American Public Health Association/American Water Work Association/Water Environment Federation: Washington D.C., 2012. (19) Herbert, D.; Phillips, P.J.; Strange, R.E. Chemical analysis of microbial cells. In Methods in Microbiology; Norris, J.R., Ribbons, D.W., Eds.; Academic Press: London and New York, 1971; Vol. 58, pp 265-277. (20) Bradford, M.M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal. Biochem. 1976, 72, 248-254. (21) Donoso-Bravo, A.; Pérez-Elvira, S.; Aymerich, E.; Fdz-Polanco, F. Assessment of the influence of thermal pre-treatment time on the macromolecular composition and anaerobic biodegradability of sewage sludge. Bioresource Technol. 2011, 102, 660-666. (22) Jin, Y.; Hu, Z.; Wen, Z. Enhancing anaerobic digestibility and phosphorus recovery of dairy manure through microwave-based thermochemical pretreatment. Water Res. 2009, 43, 3493-3502. (23) Elbeshbishy, E.; Aldin, S.; Hafez, H.; Nakhla, G.; Ray, M. Impact of ultrasonication of hog manure on anaerobic digestability. Ultrason. Sonochem. 2011, 18, 164-171.


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(24) Abouelenien, F.; Kitamura, Y.; Nishio, N.; Nakashimada, Y. Dry anaerobic ammoniamethane production from chicken manure. Appl. Microbiol. Biotechnol. 2009, 82, 757-764. (25) Huang, W.; Zhao, Z.; Yuan, T.; Lei, Z.; Cai, W.; Li, H.; Zhang, Z. Effective ammonia recovery from swine excreta through dry anaerobic digestion followed by ammonia stripping at high total solids content. Biomass Bioenerg. 2016, 90, 139-147. (26) Appels, L.; Baeyens, J.; Degrève, J.; Dewil, R. Principles and potential of the anaerobic digestion of waste-activated sludge. Prog. Energ. Combust. Sci. 2008, 34, 755-781.


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For Table of Contents Use only

Coupling Hydrothermal Treatment with Stripping Technology for Fast Ammonia Release and Effective Nitrogen Recovery from Chicken Manure

Weiwei Huang, Tian Yuan, Ziwen Zhao, Xi Yang, Wenli Huang, Zhenya Zhang, and Zhongfang Lei

SYNOPSIS: Fast ammonia recovery from chicken manure is realized by hydrothermal pretreatment and stripping technologies, simultaneously achieving enhanced subsequent methane production


30

Coupling Hydrothermal Treatment with Stripping Technology for Fast

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