Keywords : Coagulation
A Modeling Approach Towards Improving Compliance of Treated Water Quality to Reduce Manpower and Chemicals
journal of kerbala university,
2013, Volume 9, Issue 0, Pages 118-128
In water treatment processes, the individual unit operations are complex, highly non-linear and poorly understood. Whilst many models have been developed to improve process understanding, these are rarely in a form easily exploited by the control engineer. Attempts to improve the performance of water treatment works through the application of improved control and measurement have had variable success. This paper investigates the application of feed forward control on the clarification process of a small-scale pilot plant. The application aimed towards maximizing the efficiency of the chemical coagulation process. To accomplish this, a simple computer program written in Visual Basic version 6 models to achieve the process operating conditions. Mathematical models based on historical plant data covering 18 months were analyzed by stepwise multiple regression analysis. The following parameters were important determinants of coagulant dose and pH control reagents: river turbidity, pH, temperature, total dissolved solids, and plant flowrate. A predictive equation was developed from the data, of the form:
Al2(SO4)3 (mg/L) = a*Q + b*Turb + c*TDS + d*pH + e*Temp + f
While for adjusting pH, whether lime or soda ash are added, the pretreatment of water supplies involves decreasing the acidity, to soften, and to clear drinking water. Calcium oxide (CaO), commonly known as quicklime or burnt lime. The addition of lime is with the form:
CaO (mg/L) = j + k *pH
The addition form for sodium percarbonate Na2CO3 is:
Na2CO3 (mg/L) = m + n*pH
The program was designed as an aid, so the user can still customize and optimize the computer suggested design. Users are able to move forward in adjusting or optimizing the design in minutes, which is difficult for manual system.
This system is very powerful tool in improving compliance of treated water quality to reduce manpower and chemicals. This is the underlying concept behind the development of this work and to facilitate the organizations and individuals with better understanding on how their actions can have a direct impact on the treatment.