Table 5.

Mean values of neural network validation quality with 20 hidden neurons, considering different combinations of activation functions for each of wastewater quality parameters. The highest values for each parameter of treated wastewater quality are indicated in bold font.

Parameter	Activation of Output Layer	Activation of Hidden Layer
		Lin	Log	Tanh	Exp
COD	lin	0.958	0.984	0.985	0.986
	log	0.958	0.983	0.985	0.984
	tanh	0.928	0.978	0.986	0.983
	exp	0.975	0.982	0.982	0.985
TSS	lin	0.778	0.927	0.931	0.936
	log	0.894	0.888	0.957	0.893
	tanh	0.852	0.922	0.941	0.887
	exp	0.772	0.908	0.848	0.897
Turbidity	lin	0.814	0.951	0.939	0.942
	log	0.925	0.932	0.946	0.909
	tanh	0.869	0.924	0.914	0.921
	exp	0.826	0.947	0.923	0.942
pH	lin	0.441	0.452	0.517	0.510
	log	0.436	0.430	0.627	0.586
	tanh	0.439	0.544	0.581	0.605
	exp	0.463	0.471	0.571	0.444
N-NO3	lin	0.901	0.959	0.958	0.946
	log	0.910	0.949	0.959	0.927
	tanh	0.901	0.949	0.954	0.943
	exp	0.863	0.951	0.961	0.954
N-NO2	lin	0.609	0.858	0.861	0.881
	log	0.568	0.622	0.856	0.851
	tanh	0.618	0.847	0.866	0.770
	exp	0.633	0.484	0.868	0.869
N-NH3	lin	0.879	0.961	0.974	0.952
	log	0.879	0.938	0.923	0.969
	tanh	0.880	0.939	0.968	0.877
	exp	0.879	0.969	0.959	0.755
VOC	lin	0.989	0.987	0.987	0.984
	log	0.785	0.993	0.995	0.998
	tanh	0.995	0.998	0.997	0.997
	exp	0.977	0.974	0.991	0.978