Characterization and treatment of tunneling wastewater using natural and chemical coagulants.

Particles are a concern regarding tunneling wastewater, but gaps remain in understanding metal(loid)s content and coagulation efficiency. In this research, characterization of the wastewaters before and after treatment was investigated by chemical analysis and various techniques for particle characterization. Then, laboratory work was conducted to evaluate effectiveness of sedimentation and use of coagulants to remove particles and particle-associated contaminants.

A method for reclaiming nutrients from aquacultural waste for use in soilless growth systems.

The aim of this work was to develop a method that allows the recovery of nutrients from aquaculture sludge, not only to alleviate the disposal problem, but also to address the future scarcity of non-renewable fertilizers. This method includes two steps: Nutrient mobilization using aerobic digestion followed by solids precipitation using chitosan as the flocculant. The aerobic digestion experiments were conducted in aerated batch reactors, while a jar test apparatus was used to assess the capacity of chitosan to remove total suspended solids (TSS) and turbidity.

Disinfection by-products and ecotoxicity of ballast water after oxidative treatment--results and experiences from seven years of full-scale testing of ballast water management systems.

Since 2005, five different ballast water management systems (BWMSs) based on chlorination treatment have been tested by Norwegian Institute for Water Research (NIVA) according to guidelines from the International Maritime Organization (IMO). 25% and >50% of all the tested discharge samples exhibited acute and chronic toxic effects on algae, respectively. In most cases this toxicity was plausibly caused by a high free residual oxidant (FRO) level (>0.

Effect of water treatment on the growth potential of Vibrio cholerae and Vibrio parahaemolyticus in seawater.

In laboratory experiments we added Vibrio cholerae and Vibrio parahaemolyticus to bottles with seawater previously treated by filtration, UV, chlorine or ozone. The purpose was to investigate the influence of different treatment techniques on the growth potential of these bacteria in simulated ballast water tanks. Residual oxidants were removed before inoculation, and the bottles were incubated at 21 ± 1 °C.

The BIOZO process--a biofilm system combined with ozonation: occurrence of xenobiotic organic micro-pollutants in and removal of polycyclic aromatic hydrocarbons and nitrogen from landfill leachate.

We present an assessment of xenobiotic organic micro-pollutants (XOM) occurrence and removal of polycyclic aromatic hydrocarbons (PAHs) in a novel biofilm system combined with ozonation, the BIOZO concept, treating partly stabilised landfill leachate. A novel, staged moving-bed biofilm reactor (SMBBR) design was implemented in laboratory- and pilot-scale, and the PAHs removal efficiency of controlled ozonation was assessed installing the ozonation step in the nitrate recirculation line (Position 1) or between the pre-anoxic and aerobic zones (Position 2). COD removal in a laboratory- and in a pilot-scale SMBBR system with and without ozonation is additionally addressed.

Diurnal variations in the occurrence and the fate of hormones and antibiotics in activated sludge wastewater treatment in Oslo, Norway.

We present an assessment of the dynamics in the influent concentration of hormones (estrone, estriol) and antibiotics (trimethoprim, sulfamethoxazole, tetracycline, ciprofloxacin) in the liquid phase including the efficiency of biological municipal wastewater treatment. The concentration of estradiol, 17-alpha-ethinylestradiol, doxycycline, oxytetracycline, demeclocycline, chlortetracycline, cefuroxime, cyclophosphamide, and ifosfamide were below the limit of detection in all of the sewage samples collected within this study. Two different types of diurnal variation pattern were identified in the influent mass loads of selected antibiotics and hormones that effectively correlate with daily drug administration patterns and with the expected maximum human hormone release, respectively.

Climate change impacts on activated sludge wastewater treatment: a case study from Norway.

We present an investigation on climate change effects on a wastewater treatment system that receive sewage collected in a combined sewer system in Oslo, Norway, during winter operation. Results obtained, by contrasting meteorological data with sewage data, show that wastewater treatment plant (WWTP) influent flow rates are significantly increased during temporary snow melting periods above a critical daily air mean temperature of approx. -1.

Occurrence and removal of selected organic micropollutants at mechanical, chemical and advanced wastewater treatment plants in Norway.

In Norway the combined hydraulic capacity of all domestic wastewater treatment plants is relatively equally distributed between three major treatment plant types; mechanical, chemical, and combined chemical and biological. The Western coast from Lindesnes in the south to the Russian boarder in the North is dominated by mechanical treatment plants, constituting approximately 68% of the treatment capacity in that area. In the present study we report concentrations and removal efficiencies of polycyclic aromatic hydrocarbons (PAHs), nonylphenols, phthalates, polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) found in five Norwegian wastewater treatment plants (WWTPs) applying different levels of treatment.