Effect of aeration and material composition in soil mixture block on the removal of colored substances and chemical oxygen demand in livestock wastewater using multi-soil-layering systems

Figures & data

Table 1 Compositions and dry weight (g) of the materials in the soil mixture blocks in each of the four multi-soil-layering (MSL) systems

MSL System	Andisol (g)	Activated carbon (g)	Charcoal (g)	Sawdust (g)	Iron (g)
1	6451	922	0	922	922
2	8179	922	0	0	0
3	6566	922	922	0	0
4	6566	922	922	0	0

Figure 1  Structures and components of the four multi-soil-layering (MSL) systems. The size of the MSL systems was W50 cm × H73 cm × D10 cm for wastewater treatment. The size of the soil mixture block (SMB) is shown in parentheses (W cm × H cm × D cm). PL, permeable layer.

Table 2 Experimental conditions in each period (time, hydraulic loading rate [HLR], air temperature and aeration conditions) of the four multi-soil-layering (MSL) systems

Period	Time	HLR (L m^−2 day^−1)	Air temperature (°C)	Aeration (mL min^−1 per system)
1	1 Nov.–19 Dec. 2005	250	11–16	1000 (MSL 1–4)
2	20 Dec.–28 Feb. 2006	250	5–15	1000 (MSL 1–3); 2000 (MSL 4)
3	1 Mar.–27 Apr. 2006	250	9–18	1000 (MSL 1–3); 2000 (MSL 4)
4	28 Apr.–28 Jun. 2006	250	20–30	2000 (MSL 1–4)
5	1–28 Aug. 2006	250	30–35	2000 (MSL 1–4)

Figure 2  (a) Decolorization rates and (b) chemical oxygen demand (COD) removal rates in the four multi-soil-layering (MSL) systems as affected by material composition and aeration. P, period.

Table 3 Effect of material composition and aeration on mean decolorization rates and mean chemical oxygen demand (COD) removal rates in the four multi-soil-layering (MSL) systems

Period	n	MSL 1	MSL 2	MSL 3	MSL 4
Mean decolorization rate
1	6	60.7% a	61.6% a	67.1% a	67.0% a
2	9	49.2% b	49.2% b	39.8% a	48.8% b
3	8	36.5% b	26.4% a	25.5% a	40.1% b
4	7	39.5% b	31.0% b	37.6% b	26.8% a
5	4	44.4% a	50.0% a	44.4% a	46.6% a
Mean COD removal rate
1	6	50.2% a	48.8% a	52.0% a	58.0% a
2	9	39.7% b	39.1% b	29.4% a	43.3% b
3	8	26.6% ab	14.6% a	15.6% a	39.3% b
4	7	49.6% b	43.1% b	58.9% c	36.3% a
5	4	72.0% a	69.5% a	77.1% b	75.6% b
Means with the same letter in the same line within the same period are not significantly different using Tukey's honestly significant difference test (P < 0.05).

Figure 3  Decolorization rates by ion exchange resins (IER) at different amounts for 10-fold diluted livestock wastewater. Exc., exchange.

Figure 4  Molecule size distribution of colored substances in the water (a) before and after treatment with Andisol, activated carbon and charcoal with 10-fold diluted livestock wastewater, (b) before and after treatment in multi-soil-layering (MSL) systems after 6 months of operation and (c) before and after treatment in multi-soil-layering (MSL) systems after 1 month recovery. WW, waste water.