Performance Optimization of Chemical and Green Coagulants in Tannery Wastewater Treatment: A Response Surface Methodology Approach

Table 5

Analysis of variance for response surface model of %COD removal (), %TSS removal (), and SVI () with cassava starch and orange peel powder coagulants.

Term	d.f	Cassava starch						Orange peel powder
		F-value			value			F-value			value
		Model	5	12.3	10.1	223	0.002	0.004	≤0.001	15.5	17.4	1288	≤0.001	≤0.001	≤0.001
	1	46.4	0.22	64.9	≤0.001	0.653	≤0.001	16.9	0.94	4085	0.005	0.365	≤0.001
	1	3.15	43.6	308	0.119	≤0.001	≤0.001	1.68	25.1	918	0.237	0.002	≤0.001
	1	7.28	0.49	209	0.031	0.505	<0.001	51.1	1.06	1336	≤0.001	0.337	≤0.001
	1	2.99	6.44	26.1	0.127	0.039	≤0.001	4.34	14.2	11.6	0.076	0.007	0.011
	1	0.06	0.10	523	0.821	0.760	≤0.001	6.65	46.4	97.5	0.037	≤0.001	≤0.001
Lack-of-fit	3	3.31	1.21	1.96	0.139	0.413	0.262	2.36	2.46	1.31	0.213	0.202	0.388