Studying the Formation of Biofilms on Supports with Different Polarity and Their Efficiency to Treat Wastewater

Table 1

Reactors effluent concentrations (mg/L) at 4, 28, and 44 days.

Parameter	Influent concentration (mg/L)	Discharge limit (mg/L)	PVA reactor			PE reactor
			4th day	28th day	44th day	4th day	28th day	44th day
COD	250	125	13	26	25	36	39	45
-N	24	15	0.02	0.15	0.18	0.02	0.22	0.25
-N	5.0	15	21	9.4	4.1	23	35	35
-P	13	2	5.6	3.3	4.4	4.4	3.4	4.0

Based on Council Directive 91/271/EEC concerning urban wastewater treatment adopted on 21 May 1991, there is a limit (15 mg/L) only for total nitrogen.