Process control for nutrients removal using lamella sedimentation and floating media filtration

Abstract

The objective of this work is to provide an efficient method to control the dosing of chemicals in order to optimise the operation of the complete treatment train associating phosphorus precipitation in a lamellae separator followed by nitrogen removal in a Biostyr® filter with methanol addition. Four coagulation-flocculation tanks of 1.54 m3 total volume were used, followed by a lamellae primary tank of 0.65 m2 footprint and 5.4 m2 total settling surface. On-line measurements were used. The pilot was operated initially with no chemicals, at constant and variable flow. Different control strategies were sought. To help tune the controllers, step changes in chemicals dosing were made to identify the open-loop process transfer function at different flow rates. The system was then operated in closed loop. This proved to be an efficient means of operating the system. Future work will continue to test various control strategies.

Phosphorus Removal from Wastewater Using Oven-Dried Alum Sludge

“…Filtration has been used either alone or in conjunction with a coagulation process as a means to remove phosphorus from wastewater [10,11]. High-rate sedimentation has also been attempted in some studies [12,13]. Among the various physical-chemical methods, coagulation with chemical precipitation and adsorption are the most common techniques being used for removing phosphorus.…”

Instrumentation, Control and Automation in Wastewater Systems

“…Control of external carbon addition has been discussed extensively in Lindberg and Carlsson (1996), Yuan et al (1997), Zeghal et al (1997Zeghal et al ( , 1998 and Puznava et al, (1998). Isaacs et al (1995) studied the control of external carbon addition to the BioDenipho® systems.…”