Expanding ASM models towards integrated processes for short-cut nitrogen removal and bioplastic recovery.

In next-generation water resource recovery facilities (WRRFs), it is becoming increasingly important to save energy costs and promote resource recovery of valuable products. One way of reducing the substantial aeration energy costs at WRRFs is to employ shortcut N removal, while polyhydroxyalkanoate (PHA) production and recovery as bioplastic is a promising means of recovering a valuable product from biosolids. Both objectives can be achieved simultaneously through the Short-Cut Enhanced Phosphorus and PHA Recovery (SCEPPHAR) process.

Relationships between abiotic and biotic variables in a maturation pond and their influence on E. coli removal.

The effects of depth and climate seasonality on zooplankton, algal biomass, coliforms and Escherichia coli in a small full-scale shallow maturation pond receiving pre-treated domestic wastewater were evaluated during a tropical climatic seasonal cycle. The experiment revealed that the zooplankton community was dominated by rotifers and protozoans, and concentrations were influenced by seasonality. A negative correlation between zooplankton, and pH, dissolved oxygen, temperature and ultraviolet radiation, and chlorophyll-a and Escherichia coli were observed at all depths.

The impact of a seasonal change in loading rate on the nitrous oxide emissions at the WWTP of a tourist region.

Nitrous oxide (NO) is a powerful greenhouse gas (GHG) whose production and emission must be minimised from wastewater treatment plants (WWTPs) to avoid undesirable impacts to climate change and the ozone layer. WWTPs operated in tourist regions undergo large seasonal changes to the influent loading rates of organic matter, nitrogen and phosphorus, which operators must respond to by changing their operational conditions. This study examines the impact of a change in low to high season on the NO emissions of an activated sludge WWTP in a well-known tourist region in the Algarve, Portugal.

Simple mid-depth transverse baffles to improve bacterial disinfection in a shallow maturation pond - performance evaluation and CFD simulation.

Sunlight-mediated disinfection in wastewater treatment ponds is widely recognised as the main role for disinfection, but pathogen removal can be limited by poor light penetration in the water column. The aim of this research is to evaluate a different and simple type of intervention for improving bacterial disinfection, by placing mid-depth transverse baffles perpendicular to the theoretical flow in an existing shallow maturation pond, aiming at increasing the opportunity for bacteria to receive radiation at the upper layers of the pond. In order to understand the hydrodynamic mechanisms and evaluate the effectiveness of the proposed intervention, a 3D Computational Fluid Dynamic (CFD) model was applied, including the transverse baffles and a particle-tracking model.

Solar radiation (PAR, UV-A, UV-B) penetration in a shallow maturation pond operating in a tropical climate.

Solar radiation is considered the primary route for disinfection of pathogenic bacteria in maturation ponds. There is scarce information on depth profiling and attenuation of photosynthetically active radiation (PAR), UV-A and UV-B in shallow maturation ponds operating in tropical climates. Measurements of solar irradiance of the three wavelength ranges, together with turbidity, have been acquired from different depths for over 1 year in a shallow maturation pond (44 cm of depth) operating in Brazil.

Vertical profiling and modelling of Escherichia coli decay in a shallow maturation pond operating in a tropical climate.

Maturation ponds are excellent natural treatment systems for disinfecting domestic wastewater from pathogenic bacteria because of their great sunlight exposure through depth and high pH and dissolved oxygen values - all considered important factors. Escherichia coli (E. coli) removal is higher at closer to the surface of the pond and proceeds to decrease due to the limited amount of sunlight at deeper depths.