absorption of artificial piggery effluent by soil: a laboratory study. - absorption of water
Introduction of intensive pig farms often rinse urine, feces and waste feed, and irrigation is often the most effective way to use the wastewater produced.
However, the nutrient concentration is high, so care is needed to manage the material without damaging the environment.
Liquid fertilizer for irrigation in five large pig farms in the South
The eastern Australia is similar, and the pH value is between 7.
5 and 8, and high concentration of water
Soluble ammoniumnitrogen(N[H. sub. 4. sup. +]-N)and potassium ([K. sup. +])
But the calcium concentration is low ([Ca. sup. 2+]), magnesium ([Mg. sup. 2+]), and sodium([Na. sup. +]).
Smile and Smith (2004)
Provide more discussion on the performance of these materials.
They also discussed the effect of changing the cation ratio and concentration on the structural stability of the soil irrigated with wastewater.
Table 1 identifies the significant value.
This shows that N [H. sub. 4. sup. +]
Average concentration 42 [mmol. sub. c]
/L much more [K. sup. +]
Average concentration 13 [mmol. sub. c]/L.
In these events, however ,[K. sup. +]
Is considered a potential problem by the industry because it may have an impact on the soil structure and [H. sub. 4. sup. +]
It is often overlooked, presumably because the usual experience is that it disappears from the soil profile relatively quickly after irrigation.
No oxidation of wastewater treatment system N [H. sub. 4. sup. +]to N[O. sub. 3. sup. -]to [N. sub. 2]
Very common worldwide. Bernal et al. 1993; Sloan . 1999; Pote et al. 2001), soN[H. sub. 4. sup. +]
Must first participate in ion exchange, no matter how long it is
Fate in the soil. Furthermore, N[H. sub. 4. sup. +]
Similar [K. sup. +]
Both were strongly adsorbed compared to Na. Initial effect of N [H. sub. 4. sup. +]
Prominent with its high concentration, should be similar [K. sup. +]
And may regulate the effect of high concentration [K. sup. +](Bolt et al. 1976).
In principle, the fate of positive ions like [K. sup. +]andN[H. sub. 4. sup. +]
In solutions absorbed by the soil, models based on reaction chemistry and chromatography theory can be used to predict
Hutchinson and Wagenet 1992)and UNSATCHEM (
1997. decision of Suarez and acceptance; Suarez 2001).
In practice, few experiments involve migration and reaction in the process of non-saturated and unstable water flow in natural soil (Mansell et al. 1993)
Although there is a research on [competitive exchange]Na. sup. +], [K. sup. +], and [Ca. sup. 2+]
During the initial absorption of the same ion soil (
Bond and Phillips 1990a, 1990b; Bond 1997;
Bond and Fort Ville 1997).
One difficulty with these models is that they need to know in advance the adsorption dynamics of each pair of competitive ions in the presence of all other ions.
In the absence of other ions, the batch measurement between pairs of ions is routine (
Bruggenwert and Kamphorst 1979)
However, in environments that simulate the chemical conditions in the process of absorbing mixed ion solutions from natural soils, their measurements are very difficult.
The experiments described here illustrate the practical ways to solve these problems. They (i)
Test the Basic Law of water and solution flow and chemical reaction during non-chemical reaction
Stable, non-saturated soil water flow and the effectiveness of the models they support; (ii)
In the realistic environment of competition, it is allowed to estimate the adsorption of cation exchange; (iii)
Measure the delay in the ion reaction front relative to water, thus providing a supplementary comprehensive estimate of the effect on the exchange rate response; and (iv)
How to expand bond with homosexuality
Ionic soil is a chemical "natural" soil used for discharge.
The use of artificial rather than actual pigsty wastewater, but they illustrate the effect of the actual concentration [s]K. sup. +]
In the presence and absence of N [H. sub. 4. sup. +].
The initial study focused on the "chromatography" distribution of the major ions observed during the unsaturated, non-stationary flow and the "simple" exchange rules used by huttson and Wagenet (1992)and Suarez (2001).
Theory when a uniform, relatively dry, horizontal soil column absorbs the equilibrium solution from the source with a constant potential, the constant solution seems to replace the original soil solution as a whole.
At the same time, the fluid dynamics dispersion leads to the diffusion of the front of the piston, thus separating the absorption solution from the original absorption solution (Smiles et al. 1978)
The pollutant adsorption on the soil solids hinders the single Yin-Yang ion front relative to the front of the piston. If step-
[,] Functional changesC. sub. w]
, And the potential applied at one end of the column at timet = 0, and remains the same if diffusion-
Just as the flow equation works for water and solvent, and then the volume fraction of water ,[[theta]. sub. w], and [C. sub. w]
The profile observed at different times falls on the single line, and when drawn with pommannsubstitution ,[lambda]= [zt. sup. -1/2].
Z here is the distance from the soil-
Solution interface (z = 0)
, T is the elapsed time to measure the profile.
This similarity also means that there is a chemical equilibrium within the time frame of the flow (
Smile and Philip 1978.
Thus, these experiments tested the hydraulic dispersion and reaction during the non-stationary, non-saturated flow of natural flow in the field soil.
They also allow us to estimate the exchange balance between competing ions in all cation concentrations in a site-related environment.
Under these experimental conditions, the mass fraction of water ,[[theta]. sub. g], and [C. sub. w]
If we use aspace-
Like coordinates, m (z, t)
, Defined as the cumulative mass of soil solids per area, from z = 0 (
Raats and Klute 1968;
Smilesand Sentai 1968; Smiles 2000). The m(z, t)
Coordinates are related to space by soil bulk density, but more generally because it is also applicable to non-
System in which expanded soil or volume changes with water content and bulk density-
Water content relationship (
The quality of the soil is known. The m-
Coordinates are easy to measure and easy to simplify analysis in the system, for example, the distribution of reaction and active solvents is "controlled" by clay content ", among them, the accumulated clay amount provides a reasonable basis for comparing the chromatography reaction in soil with different clay contents (Raats 1998; Smiles 2001).
In this coordinate system, the solvent of each unit mass (water)or of solid (
Depending on the situation. In m-
In space, the flow equation of water and solution can be written :(1)[differential][[theta]. sub. g]/[[differential]t = -[differential]F/[differential]m and (2)[differential]([C. sub. s][[theta]. sub. g]+[C. sub. c])/[differential]t = -[differential](f +[C. sub. s]F)/[differential]
In these equations, F is the Darcy flux of water relative to the solid (Zaslavsky 1964), [C. sub. s]
Dissolution concentration of water per unit of mass ,[C. sub. c]
Concentration of pollutants related to soil solids ([mmol. sub. c]/kg), [C. sub. s]
F is the flux of the solution in contact with water, f is the flux of the solution in relation to water diffusion according to the Fick law in response [differential][C. sub. s]/[differential]z (Smiles 2001).
A lagging flow of earth and water, replacing Darcy's law in equation 1, leads to a familiar non-
Linear diffusion equation (
Smile andRosenthal 1968).
Describe Fokker with the replacement of the Fick law in equation n2-
Reiniger and Bolt 1972)
When the diffusion equation of thateroces, space
Like coordinates, based on the distribution of water, using (
The operation of this peer 2 also requires us to rewrite its left-
Hand side]C. sub. s]
This, in turn, requires us [C. sub. s]to[C. sub. c]
According to some rules of exchange (
Bond and Phillips 1990b).
The simplest of these (Crank 1956;
Reiniger and Bolt 1972)
Let's say that [the] linear "isokinetic", soK. sup. +](for example): (3)[K. sup. +. sub. ex]= B[[K. sup. +]]
Square brackets represent the place of water-
The soluble positive ion is in the form of "outer" and B is a constant.
Systematically use equation 3 in modeling (Robbins et al.
1980. Hutchinson and Wagenet 1992;
1997. decision of Suarez and acceptance; Suarez 2001).
Cationexchange, illustrated by replacing equation 3 in equation n2, replaces the front of the piston with respect to the front of the piston, and also reduces the diffusion coefficient of the related salt (Crank 1956;
Frozen and cherier 1979).
The use of Equation 3 in systems containing many competing ions needs to be derived in the appropriate ion environment, for which it represents only a quantity of "isosys ", this "heat" defines the solution of equation 2 for each competition (Bolt 1976; Robbins et al. 1980;
Bond and Phillips 1990a).
These issues will be discussed in more detail later.
In the horizontal absorption process of the solution, we believe that, influenced by the experimental conditions of equation 4, equation n 1 and qn 2 describe the transfer :(4)m = 0; t> 0; [[theta]. sub. g]= [[theta]. sub. o]; [C. sub. s]=[C. sub. s(o)]m> 0; t = 0; [[theta]. sub. g]= [[theta]. sub. i]; [C. sub. s]= [C. sub. s(i)]
In this case, boerzman substitution, M = m /[t. sup. 1/2]
, Remove m and t from the flow equation of water and pollutants and equation 4.
Then, ifEqn 1 and Eqn 2 are valid and the equation n 4 is implemented, if expressed in M = m, the distribution set of water content and solution concentration observed at different times falls on the same curvet. sup. 1/2].
In addition, the solution flow of the diffusion equation is caused when awater-
Based on coordinates, g (m, t)
, Also means the similar interval of the corresponding substitution, G = g /[t. sup. 1/2](Smiles2001)
G is a space-
Like the coordinates of the distribution based on water (Smiles et al. 1981).
Therefore, if the method is valid (i)
The experiment should produce the distribution of water and pollutants within the distance/[range](time). sup. 1/2], (ii)
The distribution of cation concentration should reflect the exchange adsorption curve related to the local environment of the competitive cation, and (iii)
The overall consequences of these adsorption should be reflected in the slowness of the reaction solution relative to the flow of water.
Materials and methods for surface soil (0-100 mm)
Deep red paste that was previously not watered with pig farm wastewater was used.
Soil contains 15-
20% clay with cation capacity (CEC)
About 55 [mmol. sub. c]/kg.
The clay is mainly kaolinite stone, which is about 20% Yili.
In the CSIRO National Soil database, it was identified as CP338 and 339 (c/-david. jacquier@csiro. au)(
Smile and Smith 2004).
Through the soil of 2-
A sieve with an initial water content of mm ,【[theta]. sub. i][
About equal to]0.
05 g/g, into the specified cylinder with an inner diameter of 20mm.
The Pillars consist of parts about 4, 6 and 10mm long, and the short part is close to the inflow end.
Soil is added in increments of 23g and packed with small drops of water
Hammer to ensure uniformity.
Analysis of cation composition similar to pig farm wastewater, but [Cl. sup. -]
Apply the unique anion to one end at zero Hydro (m = 0)
Horizontal column at T = 0.
Two sets of experiments were conducted.
The first, the main, N . [H. sub. 4. sup. +]
And Xiaoyang ,[Mg. sup. 2+]
Is the absence of artificial sewage.
The second group contains all positive ions ([Na. sup. +], [K. sup. +], [Ca. sup. 2+], [Mg. sup. 2+], N[H. sub. 4. sup. +]).
The experiment ended at different times in each group.
Experimental setup 1. slice the column at the end of the experiment.
Weigh each wet part and remove the water sample by centrifugal in the presence of an organic liquid with a specific gravity of 1. 57(
Phillips and Bond 1989).
Then filter the soil sample to remove the excess water
Remove soluble salt with ganol and exchange with 1 m n [H. sub. 4]
Cl, after further washing with alcohol, the CEC is estimated by measuring the remaining [H. sub. 4. sup. +](
Rayment and highginson 1992).
Through these operations, all soil solids are retained. Water-
Coupled Plasma spectrum by inductance (ICP)
On the water sample after dilution of a small amount of soil solution (0. 2-0. 5 [cm. sup. 3])to10[cm. sup. 3].
Measurement of exchangeable cation on N [H. sub. 4]
Atomic absorption spectrum (AAS), and N[H. sub. 4. sup. +]
The exchange capacity is measured using an automatic analyzer (
Rayment and highginson 1992).
Gravity tracking dilution, refer to the oven for all quantities-
Dry by oven, determine the soil dry quality of each part after all extraction.
Profile data is drawn in m-space, i. e.
Cumulative quality of soil per unit area
Part of the column, measured by adding an oven-
Starting from the inflow end of the column, divided by the cross-section area of the column, the dry weight of each section of the soil.
The experimental set 2 slicing program is the same as set 1, but chemical analysis becomes complex due to the need to analyze the exchangeable N [H. sub. 4. sup. +].
Therefore, we split the column part before any extraction, because the centrifugal will separate the particle size during the extraction of watersoluble salts. About two-
The water treatment described above has three samples. Soluble cation (including N[H. sub. 4. sup. +])
Measured with ICP, exchange instead of N [H. sub. 4. sup. +]
Analyzed with AAS.
The third part of the column part is cleaned with alcohol to remove water
Soluble salt and exchangeable cation were extracted with 1 M potassium chloride.
Exchangeable N [H. sub. 4. sup. +]
Analysis using an automatic analyzer method.
Initial water content, time at the end of the experiment and S ([[theta]. sub. i], [[theta]. sub. 0])
Measuring Capacity (Philip 1957)
, Two experimental sets can be found in table 2.
Influence of different running times on statistical analysis [C. sub. s]and [C. sub. c]
Analyze the profile using the nonlinear regression option of FITCURVEin GENSTAT 5 (Payne 1993).
Arbitrary curve fitting of variables ([C. sub. s]and [C. sub. c]
Go backwards in space
Like Variables, M/S (
Definition and diagram. 1b below)
, Then use the ADD instruction to test if the run time has caused a significant change in the server.
In addition to one case, non-linearity is suitable for data that account for more than 95% of the data variance in all cases.
The exception is solvable [Na. sup. +]
Only 80% of the difference. [
Figure 1 slightly]
Results and preliminary discussion of water content distribution and space
The coordinate experimental device 1 shown in Figure 1a shows the water content distribution observed in these experiments.
Within the range of acceptable experimental errors mainly caused by packaging differences, these profiles maintain similarity when M = m/[s] Graphical Interactiont. sup. 1/2]
Therefore, they are consistent with the law of water flow and the initial and boundary conditions.
This picture also shows the piston. front at M [
About equal to]1. 6-1. 8[kg. sub. solid]/[m. sup. 2]x [s. sup. 1/2]
If the absorption solution completely replaces the original soil water, this will exist.
The front of the piston was found in the water. based space-
Like coordinate G (M),defined (Smiles et al. 1981)by: (5)G(M)= [[integral]. sup. M. sub. 0][[theta]. sub. g]dM -S([[theta]. sub. 1], [[theta]. sub. o])is zero.
In fact, this is equivalent to finding the value of the shadow area M of the graph1a are equal. Non-
The active solvent spreads to water on this plane, and the chemical reaction with the solid phase causes the "diffusion" plane displacement of G (M)
= 0 depending on the size of B OFE 3 for each ionic species.
In order to reduce the impact of the change of the column packaging, fig.
Figure 1 aprofiles are standardized in figure 1
1b measures ([[theta]. sub. i], [[theta]. sub. o])
As shown in Table 2.
The subsequent discussion involved data on M/S.
Figure 1c waterbased G(M)/S v.
M/S that can be calculated from Figure 1
1b using equations (
2001 smile 20): (6)G(M)/S = [[integral]. sup. M. sub. 0][[theta]. sub. g]d(M/S)-
1 Figure 1c allows us to use awater-based space-
If we want, it's like coordination.
It also shows the front of the piston (The origin of G (M)/S)is at M/S [
About equal to]5. 5 [kg. sub. solid]/[kg. sub. water]
, And M/S = 0 corresponds to g (M)/S = -1.
Figure 1d shows the water content distribution of experimental device 2.
Similarly, they maintain similarity within the acceptable scattering range caused by packaging differences, so they again conform to the law of flow of water and the initial and boundary conditions. Sorptivity (S)
However, the value is slightly lower than the value in Set 1 and Figure 1.
The outline of Figure 1 is shown.
1d, on the normalization of measurement ([[theta]. sub. i], [[theta]. sub. o])
As shown in Table 2.
Figure 1 statistical differences of ereveals independent of the termination time of the experiment and the equality of the shadow areafront at M/S, [
About equal to]5. 4[kg. sub. solid]/[kg. sub. water].
If the figure shows M/S v.
Calculate G/S using Equation 6 and Figure 61e.
Distribution of solution concentration-
Experimental device of exchangeable cation 1 Figure 2a-
D display concentration ([mmol. sub. c]/[kg. sub. soil])
Convertible [Na. sup. +], [K. sup. +], [Ca. sup. 2+], and [Mg. sup. 2+]inM/S-space.
Analysis of arbitrary curve fitting using GENSTAT 5 (Payne 1993)
There is no reason to distinguish between data in columns sampled after different times (P> 0. 3).
Therefore, the similarity of the data is maintained, and we conclude that equation 4 is implemented, and diffusion-
Likeequations describes the transfer and chemical reactions of solvents in these two coordinate systems.
We also assume that we can compare the total data set shown in the figure. 2a-
D. later, the data of experiment set 2 is shown in the figure. 2e-h. [
Figure 1c and f show a 1:1 relationship between M/Sand G/S, so the similarity of M/S implies the similarity of G/S.
In this regard :(7)[integral][C. sub. c]dM/S = [integral]([C. sub. c]/[[theta]. sub. g])
DG/S according to the M/S and G/S intervals corresponding to the figure1c.
We are now looking at the data in M/S-space in Fig. 2a-
We ignore the variables, but let the reader refer to the named table (Table3)
In order to facilitate the comparison of solvent distribution, we also introduce the location of the center of mass of the solvent "front end ,[(M/S). sup. *]
, Calculated from the equation :(8)[(M/S). sup. *]= ([[integral]. sup. M/S. sub. 0](C -[C. sub. i]d(M/S)/([C. sub. o]-[C. sub. i][(M/S). sup. *]
The Frontier of a rectangle of the same area and height ([C. sub. o]-[C. sub. i])
As an actual profile.
It is suitable for both replacement and cation distribution of replacement exchange. Values of [(M/S). sup. *]
As shown in Table 4. In Fig. 2a-d: (i)
Ion exchange is limited to 0