Kinetics of bacterial die-off in waste stabilization ponds | |
| Author | Dissanayake, Malwila Gamini |
| Call Number | AIT Diss. no. EV-81-1 |
| Subject(s) | Sewage lagoons Sewage--Purification--Biological treatment |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | Waste stabilization ponds have been used as a means to reduce organic pollution and bacterial contamination in wastewater prior to discharge to the environment. Several mathematical models have been proposed to describe the kinetics of bacterial die-off in waste stabilization ponds. These models include only temperature and detention time as the major influential parameters, though several other parameters have been identified to influence the die-off process. Another drawback of the existing models is the assumption that the pond contents are completely mixed which is far from accurate in actual conditions. In this study a model is proposed to predict the bacterial die-off in facultative and maturation ponds under steady state conditions. The model includes the influence of parameters such as temperature, detention time, dissolved oxygen content, physical dispersion characteristics of the pond, organic loading, pH, algal concentration, light energy and light duration. The model is consisted of two major sub-models, one for the bacterial die-off rate coefficient and the other for the algal growth in the pond systems. The proposed model requires the determination of seven kinetic or stoichiometric values from both laboratory and pilot scale experimental data, using multiple linear regression technique. The individual influence of the major parameters on the bacterial die-off rate and algal concentration was depicted by using polynomial regression models. The model verification and sensitivity analysis were carried out with the data obtained from full-scale ponds treating the same sewage and from literature, and the results were also compared with those of MARAIS (1974) for coliform bacterial die-off in waste stabilizatin ponds. The comparison showed that the bacterial die-off in facultative and maturation ponds could be better predicted by the proposed model which incorporates most of the major parameters involved in waste stabilization. |
| Year | 1981 |
| Type | Dissertation |
| School | School of Engineering and Technology |
| Chairperson(s) | Nguyen, Cong Thanh ;Chongrak Polprasert ; |
| Examination Committee(s) | Lohani, B.N. ;Jindal, Vinod Kumar ;Mara, D.D. ; |
| Scholarship Donor(s) | Government of Canada ; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 1981 |