COD fractionation and biodegradation kinetics of segregated domestic wastewater: black and grey water fractions

Abstract

BACKGROUND: Household wastewater was segregated to grey and black water components as part of a recent approach aiming to separate wastewater fractions for more efficient treatment and reuse. Chemical oxygen demand (COD) fractionation and biodegradation characteristics of black and grey water were determined by means of model calibration of the oxygen uptake rate profiles. An ASM1 type of model modified for endogenous respiration was selected for this purpose.

Particle Size Distribution Analysis of Chemical Oxygen Demand Fractions with Different Biodegradation Characteristics in Black Water and Gray Water

“…In this context, gray water may be admitted as the diluted fraction of domestic wastewater. This is in accordance with the process kinetics obtained by means of respirometric analysis done by Hocaoglu et al [25]. In the study, there were no significant differences in biodegradation characteristics of black and gray water fractions and the process kinetics were very close to those reported for typical domestic sewage.…”

“…The sequential filtration and ultrafiltration test was experimentally assessed on two samples characterizing black and gray waters. The total COD in the black water and gray water samples were measured as 1010 and 370 mg/L, quite close to the average values reported for the same wastewater fractions [25]. The results related to COD are plotted in Fig.…”

“…4 indicates another interesting feature of the two size distribution profiles: As previously mentioned the generally accepted size threshold for settling is 100 mm (10 5 nm), The PSD of the upper phase confirms this threshold value, while the settled phase includes a range of much smaller particles, presumably enmeshed with and precipitated along with the larger COD fraction. Figure 5 provides a schematic comparison of results on PSD analyses and COD fractionation with different biodegradation characteristics [25] in a bar diagram format, both for black water and gray water; It shows that PSD, although not directly related, yields a good reflection of biodegradation, where particle size appears to the main parameter for differentiating and predicting COD fractions associated with different process kinetics. Major features of the experimental data illustrated in this figure may be ourtlined as follows: (i) For black water, the readily biodegradable COD fraction, S S , was determined as 14.7% of the total COD content (148 mg/L); the soluble inert COD, S I , brings another 3.7% (37 mg/L).…”

“…However, related studies did not include biodegradation aspects based on COD fractionation of these wastewater fractions aside from conventional characterization. This aspect was covered in a recent study using respirometric analysis and modeling of corresponding oxygen uptake rate profiles [25]. The study was conducted as part of a comprehensive survey on black water and gray water focusing on the fate of soluble residual organics [26] and fate of proteins and carbohydrates [27].…”

Nitrous oxide emissions in a biofilm loaded with different mixtures of concentrated household wastewater

“…So far, little research has been dedicated to N 2 O-emitting processes in more complex heterogeneous communities of interacting heterotrophic and autotrophic organisms typical for biofilm systems loaded with domestic wastewater, with the notable exception of a recent bench-scale study using synthetic substrates (Schreiber et al 2009). However, synthetic substrates may not be fully representative for real household wastewaters, which constitute a complex mixture of mineral and organic molecules (Dulekgurgen et al 2006;Hocaoglu et al 2010).…”