A Model for Optimal Treatment of Cassava Wastewater Using Anaerobic Baffled Reactor

The major components of the effluents from cassava processing industries are cyanide and starch. However it is suspected that cyanide inhibits the treatment of cassava wastewater. The experimental data were successfully fitted to a polynomial model which was used to optimize the treatment processes at a laboratory scale. The Monod and Michealis-menten models for cassava wastewater treatment was successfully calibrated and validated in an ABR system. For Michealis-Menten model, the maximum substrate utilization rate is estimated in the range: 2866.88 to 1432.84 mgl-1 and for Monod’s model, it is estimated in the range: 493 to 1242 mgl-1, which is more realistic, hence validating the empirical model as more accurate than the former, which is theoretical. The result revealed that the inhibitor constant decreased from 9.9989 to 1.6101mgl-1 as the number of baffles increased from 3 to 10. To reach a maximum COD removal efficiency of 99%, it was found that the aspect ratio of 10, 20 baffles, cyanide inhibition constant of 30 mg/l and influent flow rate of 0.8 l/min, are the required optimum operating conditions of the anaerobic baffled reactors.

Restaurant wastewater treatment with a two-chamber septic tank and a sequencing batch reactor

Restaurant wastewater in Indonesia comprises a variety of organic components that are difficult to degrade, such as COD, BOD, TSS, and oils and fats. Although grease traps are usually used to collect restaurant wastewater, the effluent still exceeds the applicable standards. For this reason, the combined technology of a two-chamber septic tank (ST) and a sequencing batch reactor (SBR) was chosen for this investigation. Both are biological treatment methods that involve an anaerobic and aerobic phase. This reactor will operate with a continuous influent flow that will be processed sequentially but discharged intermittently. The hydraulic retention time (HRT) of the ST-SBR was 12, 24, 36, and 48 hours, at aeration rates of 7 and 14 L/min, respectively. The results showed that introducing a Septic Tank increased the percentage of organic content removed and shortened the optimal HRT, resulting in a 24-hour optimal HRT and a 14 L/min aeration rate. With an average efficiency of 86.72% to 98.63% in removing organic components.

The Influent Effects of Flow Rate Profile on the Performance of Microbial Fuel Cells Model

The energy contained in wastewaters has been identified as a promising sustainable energy resource that could be harvested by using microbial fuel cells (MFC). When dealing with real wastewaters, the MFCs should be able to manage high flow rates and flow rates fluctuations. In this work, the short-term effects of the influent flow rate variations on the performance of a microbial fuel cell has been studied. With this aim, the influent flow rate was stepwise increased from 0.72 to 7.2 L/d and then stepwise decreased. The obtained results indicate that, on the one hand, an increase in the influent flow rate leads to higher chemical oxygen demand removal rates up to 396 g/(L/d) and higher electric power generation almost 18 mW/m2, but to lower coulombic efficiencies. On the other hand, the reduction of the flow rate increases the coulombic efficiencies, as well as the percentage of chemical oxygen demand removed, but decreases electric power generation. In the short-term, the exposition to higher influent flow rates causes the growth of the microbial population of the MFC, the growth of the non-electrogenic microorganisms being higher than that of the electrogenic ones. The higher growth of non-electrogenic microorganisms may lead to lower coulombic efficiencies.

A Numerical Study on Influent Flow Rate Variations in a Secondary Settling Tank

The secondary settling tank is an essential unit for the biochemical treatment of domestic sewage, and its operational effect influences the quality of effluent. Under the influence of the confluence of rainwater and sewage, wastewater use habits, etc., the inflow of the secondary sedimentation tank changes over time. In this paper, OpenFOAM, an open-source computational fluid dynamics package, was used to study the dynamic behaviors of solid–liquid two-phase flow in the tank under influent flow rate variations. A coupled method including a mixture model, drift equation and a dynamic boundary method is proposed. Numerical investigations were carried out for a 2D axisymmetric sedimentation tank using 12 cases. With increasing influent flow rate, sludge accumulates continuously in the bottom left side of the tank, sludge hopper, and inlet; the sludge blanket thickness near the right end of the tank increases continuously; and the sludge concentration in the tank approximately linearly increases with time, with a low slope. The developed framework is generic and is, therefore, expected to be applicable for modelling sludge sedimentation processes.

Uso de Canna glauca para el tratamiento de aguas residuales domésticas en un humedal artificial de flujo superficial

The design and construction of a prototype of an artificial surface flow wetland was carried out with the aim of purifying domestic waste water. Field data was taken the reactor was designed and built to assess the plant's (Canna glauca) efficiency in sewage treatment. The location, available surface, and the influent flow were considered for the design; as well as available surface and the flow of influence of the influent the hydraulic retention, the size of the rock bed, the volume of the storage tank, resistance (mechanical, presence of sulfates and cleaning and sanitization substance) and permeability were considered to ensure its service life. A prototype was built where water quality was characterized by a HI 9828-0® multiparametric probe, in the reactor tributary ans effluent. Within the most relevant results is that the amount of oxygen, pH, EC, resistivity, STDs, salinity and ORP, are parameters that were favored with the presence of the aquatic plant for the purification of waste water

Influent Forecasting for Wastewater Treatment Plants in North America

Autoregressive Integrated Moving Average (ARIMA) is a time series analysis model that can be dated back to 1955. It has been used in many different fields of study to analyze time series and forecast future data points; however, it has not been widely used to forecast daily wastewater influent flow. The objective of this study is to explore the possibility for wastewater treatment plants (WWTPs) to utilize ARIMA for daily influent flow forecasting. To pursue the objective confidently, five stations across North America are used to validate ARIMA’s performance. These stations include Woodward, Niagara, North Davis, and two confidential plants. The results demonstrate that ARIMA models can produce satisfactory daily influent flow forecasts. Considering the results of this study, ARIMA models could provide the operating engineers at both municipal and rural WWTPs with sufficient information to run the stations efficiently and thus, support wastewater management and planning at various levels within a watershed.