Abstract

The desorption behavior of ammonia nitrogen (NH3-N) in cellar sediment was studied to illustrate the influence of sediment on the quality of water in cellar rain collection. The impacts of three factors on the ability of cellar sediment to desorb NH3-N were analyzed, which include the concentration of the cellar sediment, temperature and the degree of disturbance. In addition, the isothermal balance and kinetics fitting were studied. The results show that sediment concentration, temperature, and the disturbance degree greatly affect the NH3-N desorption process. The pseudo-first-order and pseudo-second-order kinetics equations are suitable for describing the desorption process (R2 > 0.86) under the different conditions of cellar sediment concentration. The Langmuir isothermal model is more suitable for describing the equilibrium desorption of the different sediment concentrations than the Freundlich isothermal model. Ultimately, the NH3-N desorption process has a significant influence on cellar water quality. Such results could be a theoretical basis for collection, treatment, and maintenance of cellar water.

INTRODUCTION

In recent years, a shortage of drinking water in China's northwest region has been partly mitigated by the ‘121 Rainwater Harvesting Project’ and ‘Water-saving Irrigation Project’. However, a problem remains regarding the safety of the drinking water derived from the rainwater harvest. Many factors contribute to the pollution of collected rainwater, such as regional differences, overlying surfaces, rainfall volume and cellar materials (Wu et al. 2014; Tao et al. 2015). When a rainstorm occurs, rainwater, along with soil, sand and a large number of pollutants on the ground can jointly flow into water cellars. The materials in the flow will then permeate into cellar sediment. The pollutants can be absorbed by cellar sediment and undergo a series of biochemical reactions with cellar sediment, thus affecting the water quality in the cellar. Therefore, cellar sediment plays an important role in cellar water quality. Obviously, it is highly desirable to investigate the impact of cellar sediment. This forms the basis of the current study.

From the literature (Li 2014; Zhang et al. 2014), cellar water studies are mainly focused on four issues: the standard of water quality; characteristics of water quality and pretreatment technologies; advanced treatment technologies; and the management and maintenance technology/strategy of cellar water. To the best of our knowledge, there is no existing literature regarding the role of cellar sediment on water quality (Liu et al. 2016).

In this study, sediment from a household cellar rainwater collecting system in Fangli Town, Qingcheng County, Qingyang City, Gansu Province, was sampled to investigate how the desorption of ammonia nitrogen from the cellar sediment influences the cellar water quality. A kinetics simulation was conducted with a goal to provide an approach for maintaining the water quality.

MATERIALS AND METHODS

Materials

Qingyang City, Gansu Province, is a typical arid and dry area in northwest China (Figure 1), where cellar water is an important source of drinking water. In Fangli Village, as in other villages in this area, a cellar was built in every household and the rainwater was collected from the roofed courtyard. The characteristics of a typical cellar and the water are shown in Table 1.

Table 1

Profile of water cellar

Cellar materialStructureVolume (m3)Type of collecting surfaceSize (m2)Water qualityMain purpose of waterYears used
Red mud Canned 30 Roofed garden 300 Medium Domestic water 30 
Cellar materialStructureVolume (m3)Type of collecting surfaceSize (m2)Water qualityMain purpose of waterYears used
Red mud Canned 30 Roofed garden 300 Medium Domestic water 30 
Figure 1

Location of Qingyang City.

Figure 1

Location of Qingyang City.

The sediment used in this study was collected under the surface of the water in the center of the cellar using a bucket and rope (Figure 2). The thickness of accumulated sediment in the selected cellars was approximately 40 cm. After collection, the sediment samples were naturally air-dried, ground and sieved using a 120-mesh to prevent large impurities before use.

Figure 2

Appearance of cellar and sediment collection.

Figure 2

Appearance of cellar and sediment collection.

The distribution of particle sizes of the cellar sediment is shown in Table 2. The clay (≤2 μm), powder (2–50 μm) and sand (50–1,000 μm) accounted for 9.00%, 70.77% and 20.24% of the sample, respectively. The median diameter (Dm) of the cellar sediment was 22.75 μm. Physical and chemical characteristics of the cellar sediment are shown in Table 3.

Table 2

Mechanical composition and elements of cellar sediment

Median size (μm)Clay (≤2 μm)Powders (2–50 μm)Sand (50–1,000 μm)Fe2O3 (%)SiO2 (%)Al2O3 (%)MgO (%)CaO (%)
22.752 8.997% 70.765% 20.238% 5.05 53.24 12.72 2.39 9.52 
Median size (μm)Clay (≤2 μm)Powders (2–50 μm)Sand (50–1,000 μm)Fe2O3 (%)SiO2 (%)Al2O3 (%)MgO (%)CaO (%)
22.752 8.997% 70.765% 20.238% 5.05 53.24 12.72 2.39 9.52 
Table 3

Main physical and chemical indicators of cellar sediment collected

ParameterMoisture (%)Ignition loss (%)Organic matter (%)Total phosphorus (mg/kg)Total nitrogen (mg/kg)Ammonia nitrogen (mg/kg)Nitrate nitrogen (mg/kg)Nitrite nitrogen (mg/kg)
Content 32.3 9.321 0.756 480 505 273 10.061 0.042 
ParameterMoisture (%)Ignition loss (%)Organic matter (%)Total phosphorus (mg/kg)Total nitrogen (mg/kg)Ammonia nitrogen (mg/kg)Nitrate nitrogen (mg/kg)Nitrite nitrogen (mg/kg)
Content 32.3 9.321 0.756 480 505 273 10.061 0.042 

Experimental design

Experimental water samples were prepared by the addition of different quantities of cellar sediments into 200 mL of deionized water in a series of 250 mL conical flasks. In the absence of previous research related to water-cellar sediment, the varying concentrations of sediment were chosen based on the varying sediment of rivers, lakes and reservoirs. The concentrations of the sediments were set as 0.5, 1, 2, 5 and 10 g/L. Flasks were put on an oscillation facility while samples were collected at different times of oscillation under different conditions of sediment concentration, temperature and oscillation speed, shown in Table 4. Samples of the supernatant were filtered through a 0.45 μm micro-porous membrane while NH3-N was measured to determine the desorbed amount, which was used for kinetics simulation and isothermal equilibrium analysis of desorption. The main analysis methods used for the test are shown in Table 5.

Table 4

Control parameters

Temperature (°C)V (mL)Concentration of cellar sediments (g/L)Disorder degree (oscillation speed) (r/min)Sampling time (h)
20 ± 0.5 200 0.5 20 ± 0.5 48 h 
1.0 
2.0 
5.0 
10.0 
20 200 5 g/L 190 ± 5 
25 
27 
30 
20 ± 0.5 200 5 g/L 140 
165 
190 
215 
240 
Temperature (°C)V (mL)Concentration of cellar sediments (g/L)Disorder degree (oscillation speed) (r/min)Sampling time (h)
20 ± 0.5 200 0.5 20 ± 0.5 48 h 
1.0 
2.0 
5.0 
10.0 
20 200 5 g/L 190 ± 5 
25 
27 
30 
20 ± 0.5 200 5 g/L 140 
165 
190 
215 
240 
Table 5

Experimental methods

Test nameTest method
Ammonia nitrogen Nessler's reagent spectrophotometry 
Organic matter Potassium dichromate volumetric method 
Particle size Fully automatic laser granulometer, Mastersizer 2000, produced by British Malvern Instrument Co. Ltd 
Chemical composition X-ray fluorescence spectrometer, MagixPW2403, produced by Dutch Philips Co. Ltd 
Test nameTest method
Ammonia nitrogen Nessler's reagent spectrophotometry 
Organic matter Potassium dichromate volumetric method 
Particle size Fully automatic laser granulometer, Mastersizer 2000, produced by British Malvern Instrument Co. Ltd 
Chemical composition X-ray fluorescence spectrometer, MagixPW2403, produced by Dutch Philips Co. Ltd 

Desorption model

Kinetics equation of desorption

Kinetics were used to study the influence of various factors on the rate of pollutant desorption reactions. The process that causes the sediment to desorb pollutants is generally described by the pseudo-first-order and/or pseudo-second-order kinetics equations, Weber and Morris intra-particle diffusion model or Bangham pore diffusion model. In this study, the pseudo-first-order and pseudo-second-order kinetics equations were used to analyze the desorption kinetics based on the assumption that chemisorption is a control mechanism, which makes an electron public or causes electron transfer between the adsorbent and adsorbate. The Weber–Morris model was used to analyze the reaction control step and the obtained adsorbent particle diffusion rate constant. The Bangham pore diffusion model was used to describe the mechanism of diffusion channels (Wang 2014).

The pseudo-first-order kinetics equation is expressed as:  
formula
(1)
The pseudo-second-order kinetics equation is expressed as:  
formula
(2)
where q is the amount of ammonia nitrogen desorbed by sediments at t, (mg/kg); is the balanced amount of ammonia nitrogen desorbed by sediments, (mg/kg); and are the rate constant, (h−1); and t is the duration of the desorption process, (h).

Isothermal equilibrium desorption model

Isothermal equilibrium desorption models are often used to describe the mechanism of desorption. The Langmuir and Freundlich isothermal desorption models are widely recognized.

The Langmuir (L) isothermal desorption equation is expressed as:  
formula
(3)
The Freundlich (F) isothermal desorption equation is expressed as:  
formula
(4)
where is the maximum amount of ammonia nitrogen desorbed by sediments, (mg/kg); is the balanced amount of ammonia nitrogen desorbed,(mg/kg); is a desorption coefficient; is the equilibrium concentration of pollutants, (mg/kg); Kf represents the equilibrium desorption coefficient; and n is the desorption index, which is a constant.

RESULTS

Effect of the cellar sediment concentration on the desorption of ammonia nitrogen

When the concentration of cellar sediment is 0.5, 1, 2, 5 and 10 g/L, respectively, the amount of desorbed NH3-N is as presented in Figure 3. The results were derived from using an oscillation rate of 190 ± 5 r/min and temperature of 20 ± 0.5°C. The NH3-N released from cellar sediments shows a significant increase in the first 30 min, while the maximum value was reached at 30 min. The concentration rapidly declined in the subsequent 30 to 60 min, and then it slowly rose again and gradually approached the equilibrium value. At the beginning of oscillation, the water and sediment particles loosely bonded together, resulting in the rapid desorption of ammonia nitrogen and thus the rapid increase in the concentration of desorbed NH3-N. Subsequently, particles inside the sediment were gradually exposed as the mixing of water and sediment progressed, which allowed more opportunity for NH3-N to release from the solid surfaces, therefore increasing the concentration of adsorption. The ensuing decrease of NH3-N release might be explained by the fact that it is difficult to transfer and desorb NH3-N atoms which tightly bond with particles inside the sediment after the loosely joined NH3-N atoms are released. At the end of the first increasing and then decreasing process (at approximately 4 hours), the distribution of NH3-N in the water and sediment became balanced and the concentration of desorption also became relatively stable, although there were still some fluctuations.

Figure 3

Temporal variation of desorbed NH3-N at different cellar sediment concentrations.

Figure 3

Temporal variation of desorbed NH3-N at different cellar sediment concentrations.

As shown in Figure 3, the equilibrium amount of desorbed NH3-N increased with the increasing concentration of cellar sediments, but the increase in desorbed NH3-N was minor. A higher concentration of water-cellar sediment means more desorption activators (namely, water-cellar sediment) and desorption points, depending on the condition of the water. Thus, the desorption rate is increased, leading to a greater amount of desorbed NH3-N. However, the adsorption of NH3-N is also increased with an increase in sediment concentration in the cellar. That is the reason why the equilibrium amount of desorbed NH3-N slightly increases (Li et al. 2014; Wang et al. 2014; Li et al. 2016).

Effect of temperature on desorption of ammonia nitrogen

When the temperature of the water was 20°C, 25°C, 27°C and 30°C, respectively, the correlative amounts of desorbed NH3-N under an oscillation rate of 190 ± 5 r/min and a sediment concentration of 5 g/L were as shown in Figure 4. It shows that the maximum NH3-N concentration was obtained at 10 min. Subsequently, the NH3-N concentration rapidly decreased. Thereafter, the concentration slowly rose and reached a second maximum at 2 hours. After that, a similar decrease and increase in concentration occurred again. An equilibrium was reached at 4 hours. The initial increase in NH3-N concentration occurred because temperature has an effect on the surface adsorption capability of sediment particles and colloids. As temperature increases, a series of physical and chemical reactions occur in the sediment, which may cause more NH3-N release. The cause of the subsequent rapid decrease is similar to the mechanism mentioned above. There are two reasons that the second maximum occurs and an equilibrium is gradually reached. Firstly, Brownian motion is intensified as temperature goes up. Secondly, as the temperature increases, the surface tension of the liquid generally weakens, molecular spacing expands and desorption strengthens.

Figure 4

Temporal variation of desorbed NH3-N at different temperatures.

Figure 4

Temporal variation of desorbed NH3-N at different temperatures.

As indicated in Figure 4, the higher the temperature is, the higher the equilibrium concentration of desorbed NH3-N. This suggests that the desorption reaction is an endothermic reaction. From the perspective of physical desorption, desorption is only a physical effect when there is no electron transfer, formation and destruction of chemical bonds or atomic rearrangement (Lei et al. 2016). The necessary mechanisms are as follows: (a) the need for a small amount of heat; (b) low stability of adsorption; (c) a high rate of adsorption and desorption; (d) no need for activation energy; and (e) no correlation between the rate of adsorption and desorption and temperature. In general, chemical desorption is fairly intensive. It occurs when the chemical bond is forced between desorbed substances and causes desorption of materials. The main mechanisms are as follows: (a) a need for relatively high adsorption heat; (b) selective adsorption; (c) a relatively stable reaction; (d) activation energy; and (e) an increasing rate of adsorption and desorption as temperature goes up. Therefore, it can be concluded that both physical and chemical desorption rates are intensified as temperature goes up.

Effect of disorder degree on desorption of ammonia nitrogen

Figure 5 presents the amount of the desorbed NH3-N when the degree of disorder (i.e., oscillation speed) was 140, 165, 190, 215 and 240 r/min, respectively. The experiments were done at a temperature of 20 ± 0.5°C and a water-cellar sediment concentration of 5 g/L. The concentration of NH3-N rapidly increased in the early stage, then rapidly declined and finally reached equilibrium. At the beginning of the experiment, the concentration of NH3-N in the overlying water was low. There was a relatively high gradient in NH3-N concentration between the water and underlying sediments. This caused the physically adsorbed NH3-N to be quickly released, breaking the original balance. Subsequently, particles inside the sediment were gradually exposed. New adsorption sites were generated and NH3-N in the overlying water was absorbed, which reduced the amount of NH3-N in the overlying water. Then, as oscillation continued, the reaction between the sediment and overlying water continued and gradually reached a new equilibrium.

Figure 5

Temporal variation of desorbed NH3-N under different disorder degrees.

Figure 5

Temporal variation of desorbed NH3-N under different disorder degrees.

It can be seen from Figure 5 that the degree of disorder had a small influence on the equilibrium concentration of desorbed NH3-N. The equilibrium desorption concentration of NH3-N was 40 mg/kg when the disorder degree (oscillation speed) was 140r/min, whereas it was 50 mg/kg when the disorder degree was 240r/min.

Kinetics simulation of the desorption of ammonia nitrogen

The concentration of desorbed NH3-N was recorded at an oscillation rate of 190 ± 5 r/min, water temperature of 20 ± 0.5°C and different sediment concentrations of 0.5, 1, 2, 5 and 10 g/L, respectively. The resultant data were fitted using pseudo-first-order and pseudo-second-order kinetics equations. The isotherms are shown in Figures 6 and 7 and the kinetic parameters are shown in Table 6.

Table 6

Parameters of kinetics equations under the conditions of different sediment concentrations

Sediment concentrationPseudo-first-order kinetics equation
Pseudo-second-order kinetics equation
(g/L)Qe (mg/L)K1 (h−1)R2Qe (mg/L)K2 (h−1)R2
0.5 42.4 8.265E6 0.8698 42.4 1.117E26 0.8698 
42.9 1.916 0.8930 44.2 92.91 0.8645 
44.4 3.270 0.9697 45.2 205.0 0.9662 
47.2 47.2 0.9496 47.4 506.6 0.9423 
10 51.0 4.205 0.9274 51.3 427.7 0.9201 
Sediment concentrationPseudo-first-order kinetics equation
Pseudo-second-order kinetics equation
(g/L)Qe (mg/L)K1 (h−1)R2Qe (mg/L)K2 (h−1)R2
0.5 42.4 8.265E6 0.8698 42.4 1.117E26 0.8698 
42.9 1.916 0.8930 44.2 92.91 0.8645 
44.4 3.270 0.9697 45.2 205.0 0.9662 
47.2 47.2 0.9496 47.4 506.6 0.9423 
10 51.0 4.205 0.9274 51.3 427.7 0.9201 
Figure 6

Pseudo-first-order kinetics for desorption of NH3-N under the conditions of different sediment concentrations.

Figure 6

Pseudo-first-order kinetics for desorption of NH3-N under the conditions of different sediment concentrations.

Figure 7

Pseudo-second-order kinetics for desorption of NH3-N under the conditions of different sediment concentrations.

Figure 7

Pseudo-second-order kinetics for desorption of NH3-N under the conditions of different sediment concentrations.

As shown in Figures 6 and 7, it seems not perfect to use both the pseudo-first-order and pseudo-second-order kinetics equations to reflect the entire NH3-N desorption process (R2 = 0.2–0.6). The reason for this is that the data did not fit the early stage when the NH3-N concentration rapidly increased due to the release of NH3-N in the sediment, followed by a decrease. Therefore, data for the first 30 min were removed and the remaining data were fitted using the pseudo-first-order and pseudo-second-order kinetics equations.

As shown in Table 6, good correlations (R2 = 0.86–0.97) were then obtained using the pseudo-first-order and pseudo-second-order kinetics equations after the removal of the first 30 min data. It demonstrated that the long-term desorption process of NH3-N in water-cellar sediment can be relatively well fitted by the pseudo-first-order and pseudo-second-order kinetics equations, although they are not suitable for describing the initial dynamic process (Xia et al. 2013; Wu 2014). The Qe (the equilibrium amount of ammonia nitrogen that a unit of sediment desorbs) increases as the concentration of sediments increases. This indicates that there is a positive correlation between the equilibrium amount of NH3-N that a unit of sediment desorbs and the concentration of sediment at a certain temperature and oscillation speed. Qe obtained from the pseudo-first-order kinetics equation is slightly larger than that from the pseudo-second-order kinetics equation. In addition, compared with an increased gradient of the sediment concentration, the increase in the gradient of Qe is small. Also seen from Table 6, kinetics coefficients (k1 and k2) gradually increase as sediment concentration increases, except when the concentration of sediment is 0.5 g/L. When the concentration of sediment is 0.5 g/L, k1 and k2 reach their maximum values (8.265E6 and 1.117E26, respectively). This indicates that there is a small mutual influence among sediment particles on the release of NH3-N in low concentrations (0.5 g/L) and that an equilibrium can quickly be reached. When the concentration of sediment increases from 1 g/L to 10 g/L, k1 increases from 1.916 to 4.205, while k2 increases from 92.91 to 506.6. Obviously, k1 is the lowest under the condition of 1 g/L because of both the mutual influence among sediment particles on NH3-N release and the strengthened absorption that occurs with the increase in the concentration of sediment.

Isothermal equation of desorption of ammonia nitrogen

When sediment concentrations were 0.5, 1, 2, 5 and 10 g/L, respectively, the equilibrium amount of NH3-N was recorded under the conditions of an oscillation rate of 190 ± 5 r/min and a water temperature of 20 ± 0.5°C. The results were fitted using the Langmuir (L) isothermal equation and Freundlich (F) isothermal equation. The isotherms are shown in Figure 8, while the kinetic parameters are shown in Table 7.

Table 7

Parameters of isothermal equations

Langmuir fitting parameters
Freundlich fitting parameters
Sm (mg/kg)kl (h−1)R2Kf (h−1)nR2
0.0528 4.6894 0.9972 0.0423 0.1002 0.9935 
Langmuir fitting parameters
Freundlich fitting parameters
Sm (mg/kg)kl (h−1)R2Kf (h−1)nR2
0.0528 4.6894 0.9972 0.0423 0.1002 0.9935 
Figure 8

Isothermal equations.

Figure 8

Isothermal equations.

As shown in Figure 8, the equilibrium amount of desorbed NH3-N gradually increased until stability was obtained with the increase in the concentration of cellar sediment. It shows that the concentration of cellar sediment has significant impact on the equilibrium concentration of ammonia nitrogen (Zhao et al. 2015).

In Table 7, K1 (the desorption equilibrium constant of the Langmuir isothermal equation) is equal to the ratio of adsorption and desorption. It is related to the surface combined energy of the sediment particles and reflects the spontaneous degree of the absorption and desorption reaction. The higher its value, the higher the spontaneous degree of the absorption and desorption reactions and the stronger the desorption ability of the desorption material. Sm (the maximum amount of contaminant desorbed by the sediment) represents the ability of the sediment to desorb the contaminant. The value of Sm divided by C (the concentration of NH3-N in the sediment of the raw water) is 19.34%, indicating that the storm or artificial disturbance causes NH3-N in the sediment to be released again into the water and thus causes secondary pollution of the water. Overall, it is evidenced from R2 (0.9972 and 0.9935) that both the Langmuir isothermal and Freundlich isothermal equations are suitable for fitting the process of sediment desorbing NH3-N.

CONCLUSIONS

Rainwater collected in cellars is used as drinking water in villages in northwest China. An anoxic environment is easily formed in water cellars, which increases microbial reproduction and impairs water quality. The desorption behavior of NH3-N from cellar sediment was studied to provide useful information on cellar water safety. The experimental results demonstrate that the concentration of sediment, the temperature and the degree of disorder have positive correlations with the equilibrium amount of desorbed NH3-N. Among them, the sediment concentration is the most significant factor to influence NH3-N desorption, thus influencing the cellar water quality. This provides insight into the improvement of the cellar water quality by controlling the pollutants in the sediment. Both pseudo-first-order and pseudo-second-order kinetics equations are suitable for fitting the NH3-N desorption process. The Langmuir isothermal equation is more suitable for fitting the relationship between initial and equilibrium concentrations of NH3-N than the Freundlich isothermal equation.

ACKNOWLEDGEMENT

The authors gratefully acknowledge the financial support provided by the Natural Science Fund of China (No. 51468033) and the Gansu Province Key Research and Development Plan (17YF1NA056).

REFERENCES

REFERENCES
Lei
X. L.
,
Han
Y. X.
,
Ran
B.
&
Yang
C.
2016
Research on the influence of environmental factors on the release of pollutants in the Three Gorges reservoir area
.
Chinese Journal of Environmental Engineering
34
(
1
),
47
50
.
Li
H.
2014
Research on Adsorption and Desorption Characteristics and Influencing Factors of Ammonia Nitrogen in Loess Belt
.
Master thesis
,
Chang’an University
,
Xi’an
,
China
.
Li
Z.
,
Tang
H.
,
Xiao
Y.
,
Zhao
H.
,
Li
Q.
&
Ji
F.
2014
Factors influencing phosphorus adsorption onto sediment in a dynamic environment
.
Journal of Hydro-Environment Research
10
,
1
11
.
Li
X. X.
,
Zhang
Y. J.
&
Zhao
X. L.
2016
Research on pilot experiment of PAC/PDMDAAC composite coagulant used in winter Taihu lake water reinforced coagulation process
.
Chinese Journal of Applied Basic and Engineering Sciences
24
(
1
),
157
167
.
Liu
D. X.
,
Li
Q. Q.
,
Li
T. L.
,
Wang
W.
&
Jin
C. H.
2016
Research on water quality and influencing factors of roof runoff in coastal cities of northern China
.
Chinese Journal of Environmental Science and Technology
39
(
12
),
100
105
.
Tao
Q.
,
Yao
J.
,
He
S. F.
,
Ma
X. F.
&
Liang
Y.
2015
Research on migration and transformation of heavy metal elements in polluted soil with different rainfall intensity
.
Chinese Journal of Soil and Water Conservation
29
(
2
),
65
68
.
Wang
J.
2014
Ecological Dynamics Simulation Technology Research on Large Shallow Lake – Taihu Lake as an Example
.
Master thesis
,
Dong Hua University
,
Shanghai
,
China
.
Wang
L.
,
Liang
T.
,
Zhong
B.
,
Li
K.
,
Zhang
Q.
&
Zhang
C.
2014
Study on nitrogen dynamics at the sediment–water interface of Dongting Lake, China
.
Aquatic Geochemistry
20
(
5
),
501
517
.
Wu
J. Y.
2014
Study on Pollutant Characteristics and Filtration Control Technology of Runoff Rainwater Particles
.
Master thesis
,
Beijing University of Civil Engineering Architecture
,
Beijing
,
China
.
Wu
F. P.
,
Xia
C.
,
Wang
Y. Q.
,
Liu
S.
,
Zhang
G. Z.
&
Yang
H.
2014
Quality and its variation of water in rainwater collection cellar of rural areas of northwest China
.
Chinese Journal of Environmental Engineering
8
(
9
),
3541
3545
.
Xia
J. G.
,
He
F. F.
&
Luo
W.
2013
Research on effects of soil components on adsorption and desorption kinetics of aluminum in Mongolian tea garden
.
Chinese Journal of Agricultural Environmental Science
27
(
1
),
358
366
.
Zhang
G. Z.
,
Cheng
X. Q.
&
Han
M.
2014
Research on harvested rain water pollutants removal in the different green artificial ecosystem
.
Environmental Engineering
32
(
3
),
10
14
.
Zhao
D. Y.
,
Wang
Y. D.
&
Wang
E. L.
2015
Research on effects of different natural organic components on the desorption characteristics of ammonia
.
Chinese Journal of the Earth Environment
6
(
2
),
113
119
.