An Alternative Method to Estimate Influent Concentration Using On-site Lab-scale Activated Sludge Reactors

Abstract

Conventional wastewater analysis based on on-site sampling holds a limitation of accuracy because of fluctuation of influent composition in time and its corruptible nature in organics. To cope with the problem, this study aimed at developing an alternative method using on-site lab-scale activated sludge reactors, where a set of mean influent material concentrations was calculated from the analysis of activated sludge constituents of which fluctuation was damped due to long sludge retention time. Focusing on the activated sludge collected from the reactor having a primary settling tank, the soluble biodegradable material concentrations in the influent were calculated using IWA Activated Sludge Model. Similarly the concentrations of inert and biodegradable particulates in the influent were obtained from the increment of activated sludge constituents between the reactor without a primary settling tank and that with a primary settling tank. The specific decay rate of the activated sludge, which was an influential kinetic parameter on the mathematical calculation, was also regularly monitored. According to the statistical analysis, 6 collection frequencies seemed to be enough to grab the parameter. This new method required noticeably low manpower to estimate particulate BOD, soluble BOD, SS and VSS in the wastewater compared to the conventional techniques.

Dynamic Estimation of Hourly Fluctuation of Influent Biodegradable Carbonaceous and Nitrogenous Materials Using Activated Sludge System

“…For the reason that temperature was an influencing factor on microbial kinetics [17], the b OHO and µ max_NAO were normalized at 20°C with the temperature coefficient θ OHO (20°C) = 1.029 and θ NAO (20°C) = 1.072 [7,19], leading to b OHO (20°C) = 0.169 1/d and µ max_NAO (20°C) = 0.402 1/d respectively. These obtained kinetic parameter values from the batch experiments seemed to be comparable to those in literature [6,7,11,20]. The probable ranges of specific decay and specific growth rate after normalization at 20°C were respectively calculated as b OHO (20°C) ≈ 0.150~0.188 1/d and µ max_NAO (20°C) ≈ 0.369~0.435 1/d.…”

“…According to recommendation from CH2 M Gore and Storrie Ltd [22], an installation of an auto-sampler equipped with refrigerator was required when performing on-site water sampling. In addition, Nguyen [6] also pointed out that total organic carbon concentration in the municipal wastewater was decreased by 20-30% after 2-day storage at 4°C, therefore daily sampling might be required even availability of 1-day delivering at the experimental site.…”

“…Recently, Nguyen et al (2016) demonstrated a backcalculation method using a set of lab-scale activated sludge reactors, whereby the composition of activated sludge which was the direct consequence of the influent materials were analyzed and those were then calculated respectively [6]. Nonetheless, the research merely revealed the approach on weekly estimation of influent concentration associated with the acceptance of influent unchangeability during a specific time step (7 − 8 days).…”

A Novel Method to Determine Blower Capacity of Wastewater Treatment Plants for Dry and Wet Weather Conditions

“…As mentioned in the introduction section, the continuous operation of the field-test activated sludge reactor(s) equipped with DO and nitrate sensors was needed to estimate the dynamic change of influent oxygen demand (biodegradable substances) together with off-line batch analysis to measure the kinetics and biomass concentration in the reactors. The datasets obtained from the field experiments were dynamically analysed in the IWA-Activated Sludge Model #1 (ASM1) to perform the back-calculation for the influent characterisation [12,14]. From the numerical calculation, the estimated concentrations of biodegradable substances were expressed in a discrete form (discrete concentration in every 1-hour).…”

“…When the dynamic responses are recorded as the system outputs, the system inputs (influent) can be mathematically obtained using the ASMs in an inverse manner. Using the method Nguyen Duong et al (2017) successfully demonstrated to obtain the ASM-based weeklyaverage influent concentrations from the analysis of activated sludge fractions (dynamic changes of heterotrophic/ autotrophic biomass and unbiodegradable organic particulates during the 7 days) [12]. Unfortunately, their approach is not possible to estimate the hourly influent concentrations because the increment/decrement of the bacterial fractions within 1-hour are too small to be identified.…”