Data collection and analysis

Paper I: To evaluate the microbial water quality trend and to understand the probabilistic behaviour of an extreme microbial load of the drinking water source, the time series data on indicator microorganisms, at drinking water plant was utilized. The data was based on weekly records of five indicator microorganisms in the NRV raw water source namely, heterotrophic plate count (HPC), Clostridium perfringens (C. perfringens), intestinal enterococci (IE), Escherichia coli (E. coli), and total coliforms (TC). The data for E.coli and coliform bacteria were from 1999 to

2013, for intestinal enterococci from 2002 to 2013, and for HPC and C.perfringens from 2005 to 2013. The physicochemical water quality parameters, temperature, pH, electrical conductivity, turbidity, river discharge, and colour were also utilized.

Paper II: In order to understand the influence of different processes (rainfall, discharge from boats, and wind directions) on the microbial water quality of the recreational beaches, hydrodynamic modelling, using E. coli as an indicator was performed. The input data for the GEMSS hydrodynamic model calibration and simulation were obtained from different sources.

Meteorological and hydrological data were collected from the Norwegian meteorological institute (eKlima), the Norwegian marine data centre, Bærum municipality and direct observation. The data used for this modelling include air temperature, dew point temperature, sea temperature, wind direction, wind speed, solar radiation, cloud cover, salinity, wave height, discharge rate (flow rate) and E. coli concentration in the river and combined sewer overflow (CSO). The main discharge came from the Sandvikselva River and two CSO sites. The E. coli concentration and the corresponding water flows were monitored in the Sandviksilva River before, during and after the rainfall. Moreover, the two CSOs discharged directly into the Oslo fjord were recorded on-tile based and the time of overflow was converted into volume in order to use as input for the model, assuming that 50% of the sewage discharged in this period. In this study, the impact of boat discharge and wind direction on bathing water quality was investigated based on scenarios. The boat discharge scenario was if a single boat with 200-litre toilet tank discharges its sewage at 300 meters from the nearest beach according to the regulation of boat sewage discharge in the Oslo fjord (E.coli concentration 3 x 10⁷ MPN/100 ml, equivalent to one day-production of E. coli from four persons). Moreover, the wind direction scenario was developed by adjusting the wind input data set, by tuning all winds into one direction using the average wind speed for all.

Paper III: The study considered the heavy rainfall event in the Sandvika area, specifically the rainfall event of 7 July 2014, which utilized the same hydrodynamic modelling of Paper II. In order to simulate for the rainfall event, E. coli concentration in the beach water was analysed for four consecutive days after rainfall event to evaluate the model performance. The simulated E.

coli concentrations at each beach were transformed into the concentration of pathogens (Norovirus, Campylobacter, Salmonella, Giardia and Cryptosporidium) based on the concentration of reference pathogens and E. coli in the sewer system from the previous studies (Grøndahl-Rosado et al. 2014; Langeland 1982; Myrmel, M. et al. 2015; Robertson & Gjerde 2006). However, the concentration of Campylobacter was estimated based on the epidemiological data from the Norwegian Surveillance System for Communicable Diseases (MSIS).

Paper IV: For the decay rate experiment, the concentration of FIB and microbial pathogens, namely total coliforms, E. coli, intestinal enterococci, adenovirus (adv40), and MS2 were analysed.

Seawater samples were characterized by their physicochemical parameters using standard methods. These parameters were pH, conductivity, salinity, total organic carbon, turbidity, zooplankton and algae. Zooplankton and algae were analysed by microscopy and heterotrophic plate count (HPC) was analysed by the spread plate method. Total coliforms and E. coli were quantified using a most probable number method (MPN) with Colilert-18 (IDEXX). IE was quantified after membrane filtration using the ISO 7899-2 method. The results were given as

colony forming units (cfu). Adenovirus (Adv40) was detected using primers and probe Brilliant III Ultra-Fast qPCR Master Mix (Agilent Technologies). In order to detect MS2, RT-qPCR was performed using the RNA UltraSense™ One-Step Quantitative RT-PCR System kit (Invitrogen, USA) and primers, probe and RT-qPCR conditions. In addition, the abundance of FIB in greywater, blackwater and combined municipal wastewater were monitored to quantify the concentration in this wastewater system.

Paper V: With the intention to investigate the health risk associated with the recycling of greywater for hydroponic lettuce production, information about effluent water quality, microbial contamination of the edible part of the plant and bioaccumulation of heavy metals in the plant tissue were analysed. Water samples were collected every two weeks from raw greywater, biofilter system effluent, filtration column effluent (green wall), and circulated irrigation water.

The water samples were analysed for total phosphorus (P) and total nitrogen (N) using spectrophotometric test kits (Hach-Lange); total coliforms (TC) and E. coli were quantified using the most probable number method (MPN) with Colilert-18 (IDEXX). In addition, water samples were collected from the same position to analyse heavy metals by using inductively coupled plasma mass spectrometry (ICP-MS). Seven to ten replicates of the lettuce plant, from each treatment plots, were collected to evaluate the plant growth status, the surface area of a fresh leaf, fresh and dry mass of the leaf, fresh and dry mass of the plant, fresh and dry mass of the root system, and number of leaves per plant. Heavy metal bioaccumulation in the plant tissue was analysed using inductively coupled plasma mass spectrometry (ICP-MS). In addition, the plant tissue was examined for microbial assay, 25 g of composite lettuce sample from each treatment plots were collected and put into stomacher plastic bags containing 225 ml sterile buffered peptone water (0.1%), homogenized by using a stomacher for 1 minute. E. coli were enumerated from the homogenised supernatant using the most probable number method (MPN) with Colilert-18 (IDEXX).

Paper VI: In order to study the virus, bacteria and nutrients removal efficiency of treated greywater disposal system, both unsaturated and saturated flow media were constructed and the physicochemical properties of experimental columns and trench were characterized. The particle size distribution of the filter media on a weighted base was analysed in triplicate from each media by standard operating procedure, LS 13 320 Laser Diffraction Particle Size Analyser (Fraunhofer.rf780d optical model, Beckman Coulter, Inc. USA). Besides, the transport of conservative tracer in the unsaturated filtration media and saturated trench were examined using sodium chloride (NaCl). The breakthrough of NaCl was monitored in the form of electrical conductivity (μS/cm) using EC meter. The effluent was analysed for physicochemical parameters using standard methods: pH, EC, total phosphorus (P), total nitrogen (N) using spectrophotometric test kits (Hach-Lange, Berlin, Germany). Total suspended solids (TSS) were determined with 1.2 μm glass fiber filters (Whatman GF-C, GE Healthcare, and Little Chalfont, UK) and turbidity was measured with light scattering. The indicator microbial pollutants considered in the study were bacteria (total coliforms and Escherichia coli) and model virus (Salmonella typhimurium phage 28B (St28B)). The St28B was propagated using a host culture of S.

enterica Typhimurium type 5. The St28B enumeration was carried out using a double-layer agar plaque assay. First, Petri dishes with 20 ml solid bottom-agar (growth medium with 1.5 % w/v

agar) were prepared. Then, 0.5 ml sample (after serial dilution in 0.9 % NaCl, if needed), 0.5 ml exponential growth-phase host culture, and 4 ml molten top-agar (growth medium with 0.65 % w/v agar), were mixed and poured over the solid agar in the petri dishes. Finally, samples were incubated at 37 ^oC for 18 hours and plaques were counted. Enumeration of total TC and E. coli was performed using Colilert-18 with Quanti-Tray/2000 (IDEXX Laboratories, USA) using the most probable number method (MPN) according to ISO 9308-2:2012.