Water Quality Assessment

Past Projects

Determination of mixing zone of treated wastewater from Alliance Mataura discharged into the Mataura River: a mixing modelling approach using contaminant tracers

To support a new discharge consent application, Dr Dada modelled the mixing of contaminants (nitrogen, phosphorous, microbial pathogens) following discharge of treated wastewater into the Mataura River, Southland. The EFDC Explorer model (Environmental Fluid Dynamics Code), a general-purpose, state-of-the-art hydrodynamic modelling package for simulating three-dimensional flow was used to determine the spatial extent of the mixing zone.

Assessment of ecological and human health effects on the Waikato River associated with the discharge of untreated wastewater from the Bridge Street wastewater pump station

Dr Dada led a study that assessed the effects of a 19-hour raw wastewater discharge from the Bridge Street pump station into the Waikato River. The study also included an assessment of potential public health risks from microbial pathogens present in wastewater. Using mass balance dilution modelling and Monte Carlo Simulations, raw wastewater concentrations of key analytes (nutrients, faecal indicator bacteria, biochemical oxygen demand and total suspended solids) were combined with quantitative water quality data for receiving waterbody to predict how the spilled wastewater would affect water quality.

Assessment of Ecological Effects for MBR WWTP treating sewage discharging to Lake Waikare

Effect of Proposed Treated Waste Water Discharge into Lake Rotorua

Dr Dada worked alongside Prof David Hamilton and Dr Jonathan Abell to execute a study which sought to provide expert opinion on the potential impact (nutrients / pathogens / pH / metals / temperature) of a proposed treated wastewater discharge through Te Arikiroa Stream into Sulphur/Puarenga Bay, when the previous discharge consent expired in 2019.

Occurrence of antibiotic resistance in recreational aquatic environments

These studies were conducted with a view to conducting bio-surveillance, detection, speciation and reporting of antimicrobial resistance incidence in faecal indicator bacteria (FIB) in waterways. In these studies, Dr Dada successfully used several advanced molecular techniques (e.g. Random Amplified Polymorphic DNA-based [RAPD-PCR] and Multilocus sequence typing [MLST]) to elucidate the presence of genetically diverse fecal bacteria with associated virulence traits and a background of recombination events in surface recreational water. 

Dr Dada worked alongside Drs Jim Cooke and Mike Stewart (@Streamlined Environmental) to assess  the potential effects of discharging Membrane Bioreactor (MBR) treated effluent to Lake Waikare (near Te Kauwahata, TeK) from a proposed 194 ha lakeside residential development. Dr Dada compared the microbial risk of the current Te Kauwhata township WWTP discharge (Aquamat pond-based) with an MBR-treated discharge from the combined TeK township + Lakeside Development. A combination of monitoring for specific microbial pathogens) and hydrodynamic modelling coupled with QMRA was used to estimate public health risk during recreation (swimming and duck shooting) at selected sites in Lake Waikare. 

Assessment of ecological effects from discharge of wastewater and stormwater on the receiving environment associated with the development of Whitford Manor Estate

Dr Dada worked alongside Dr Mike Stewart (@Streamlined Environmental) to assess the environmental effects of Membrane Bioreactor (MBR) treated-wastewater discharge from a new development near the Whitford township, Auckland. Dr Dada used mass balance dilution models and predictive faecal indicator bacteria models to show that the proposed MBR discharge will export significantly lower nutrient and microbial loads to the receiving environment than is currently the case. Microbial monitoring for specific microbial pathogens (faecal indicator bacteria -E. coli and Enterococci) informed a microbial assessment that was used to determine, with reference to specific policy directives, whether the proposed discharge is likely to result in any significant adverse effects on the receiving environment.