Influences of Limited Ammonium Nitrogen and Water Temperature on the Urban Stream Restoration Using Bacterial Technology – View from the Perspective of Numerical Modelling

Abstract

To complete the previously information issued on the feasibility study and some technical challenges identified from the application of bacterial technology, this study presents another characteristics of numerical output as the bacterial growth is now also limited to ammonium nitrogen and water temperature. Based on the results obtained, it is found that the degradation of readily biodegradable COD will be much slower because of lower bacterial growth. At certain period, the COD concentration will increase and be plotted higher later on compared to the model which is limited only to substrate and oxygen. Besides the ammonium nitrogen, other parameters i.e. particulate products from COD decay and particulate degradable organic nitrogen will also increase soon after certain time. Considering the increase of ammonium nitrogen as it is also converted to nitrate nitrogen, it can be predicted that some algae may show up during the treatment processes. When the model is simulated under different water temperature, slower biodegradation process is presented at lower water temperature. Because the bacteria grow better at higher water temperature, more oxygen is then required. Finally, from this study, it is also identified that the artificial mixing and addition of oxygen at initial stage of treatment will considerably influence the restoration.

Numerical Modeling and Practical Experience of Xuxi River's Natural Restoration Using Biological Treatment

“…It also was found that, although the water is now clearer and contains aquatic life, there is still a considerable increase in the concentration of total phosphorus, total nitrogen, and ammonium-nitrogen. Using the same selected model parameters as presented previously by the same model in Yudianto and Xie (2010c) (Figure 5), because of the conversion of ammonium to nitrate before it increases, there will be a potential of some algae to appear during the treatment processes. Besides the ammonium-nitrogen, other parameters (i.e., particulate products from COD decay and particulate degradable organic nitrogen) also may increase after they reach their minimum concentrations.…”

“…Besides describing the practical setting of biological treatment implemented at the Xuxi River, to understand the relationships between bacterial growths, substrate removal, dissolved oxygen, and other forms of nitrogen in a stream, this study also includes verification of the developed numerical model. Basically, the model was developed based on combination of Streeter Phelps and some kinetics equations used in Activated Sludge Model No.1 (ASM-1) (Jeppsson, 1996) under certain circumstances of limiting parameters (Yudianto and Xie, 2010c). Although ASM-1 has been extended to broader forms, the original model probably is still the most widely used for describing biodegradation processes.…”

“…Numerical Computation. As the above problems are formulated as partial differential equations (PDEs), and because there has been some evidence of high accuracy of numerical solution given by MATLAB using the pdepe solver function (Yudianto and Xie, 2008a, 2008b, 2010a, 2010b, 2010c, MATLAB was selected to be used in this study to conduct the entire simulation. Generally, it is necessary to introduce this solver method because it offers more possibilities and flexibility for both beginners and experts to evaluate or even invent a model, as there have been numerous mathematical functions developed inside MATLAB.…”

Integrated Evaluation of Urban Water Bodies for Pollution Abatement Based on Fuzzy Multicriteria Decision Approach

“…Due to these considerations, we can adopt the new technique as BT with complete confidence. Their bacteria are usually hired to vitiate pollutants or nutrients into simple or nontoxic entity and produce suitable effluents [ 16 ]. This technology has reassuring advantages compared to other traditional techniques as already discussed.…”

“…It was determined to be successful with reliable results in boosting up the recovery processes of all water bodies compared to the other traditional technologies. It extends for the rehabilitation of polluted lakes, rivers, and streams and is also reliable for the requirement of the wastewater effluent standards without constructing massive structures as compared to the other conventional methods [ 15 , 16 ].…”