Session 25 - Wastewater treatment

The present study evaluated the operational efficiency of a constructed wetland (CW) located at Andritsaina/Krestena municipality (Western Greece, Peloponnese, Greece), using a battery of tests and bioassays. Specifically, raw WWs entering the CW basins with broadleaf cattail Typha latifolia (raw-WWs) and biologically treated WWs effluents ending up in the adjustment tank were randomly collected in October, December 2018, and January 2019. Thereafter, freshwater algae (i.e., Chlorococcum sp., Scenedesmus sp.), invertebrates (i.e., Thamnocephalus platyurus, Brachionus calyciflorus), higher plant species (i.e., Sorghum saccharatum, Lepidium sativum and Sinapis alba) and human lymphocytes were treated with WWs for determining critical toxic endpoints in any case. All data were further interpreted with physicochemical parameters, like conductivity (Cond), COD (total and dissolved), total suspended solids (TSS) and volatile suspended solids (VSS), commonly measured in both raw- and treated-WWs samples. The results showed that almost all chemical parameters measured in treated-WWs were lower than those occurred in raw-WWs, and significantly related with the obtained critical toxic endpoints in all cases. Those preliminary findings give rise to the importance of using a battery of bioassays as useful tools for assessing CWs treatment process efficiency thus contributing to the environmental sustainability and human health.

Session: 25, Room: A, at Fri, 09/06/2019 - 12:51 to 12:54
Flash presentation in Wastewater treatment

Isolation of microorganisms that can biodegrade organic compounds which are present in olive mill waste and more specifically microorganisms that can survive at high phenol concentrations was studied in the Environmental Engineering Laboratory for three months in the Department of Environmental Science and Technology in the Cyprus University of Technology. Firstly, liquid crops were created, then the samples were cultivated in solid crops (with phenol as the sole carbon source) and at last isolation and purification of the samples were performed and the single colonies were replicated in liquid crops to check their performance. Eight single microbial culture will be sent to Macrogen The Nederlands Research Center for recognition and identification.

Session: 25, Room: A, at Fri, 09/06/2019 - 12:48 to 12:51
Flash presentation in Wastewater treatment

The aim of this paper is to assess the environmental risks associated with the wastewater reuse with respect to six metals; cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in the city of Dubai. Treated Sewage Effluent (TSE) is used for landscape irrigation. Samples of soil and control soil as baseline measurement were collected to calculate the contamination factor (CF), pollution load index (PLI), metal pollution index (MPI), degree of contamination (CD) and modified degree of contamination (mCD) of heavy metals in soil. The results revealed that the values of the CF were very high, the PLI and MPI were high, the CD was very high, and the mCD was ultra-high.

Session: 25, Room: A, at Fri, 09/06/2019 - 12:30 to 12:45
Oral presentation in Wastewater treatment

Anaerobic ammonium oxidation (anammox) has been considered a promising alternative to the traditional nitrification/denitrification process to remove nitrogen without using external carbon source. The start-up of the anammox process was performed in a stirred anaerobic up-flow reactor seeded with aeration tank sludge, and fed with medium containing ammonium and nitrite (1:1). The reactor was running consecutively for 369 days, with an initial instability period that lasted 117 days, resulting in nitrite removal and nitrate accumulation. In view of this, the reactor stopped being fed with nitrite, which led to a nitrate decrease in the effluent. Afterwards, a 140 days transition period was followed by a 112 days stable period. In the end, the average ammonium removal was 53.8 % in the transition stage, slighting decreasing to 45.6 % in the stable period, while there was no nitrite in the effluent. Preliminary microbial assessment showed the presence of an anammox community in the reactor related to Candidatus ‘Brocadia fulgida’. The next challenge will be the assessment of eventual shifts on the microbial community structure and composition during the entire process.

Session: 25, Room: A, at Fri, 09/06/2019 - 12:45 to 12:48
Flash presentation in Wastewater treatment

Investigations of simultaneous removal of ammonium and sulphate were carried out in anaerobic laboratory bioreactor - upflow anaerobic filter (UAF). The process was operated in psychrophilic conditions. Temperature was maintained constant at 20±2°C. Synthetic wastewater containing ammonium chlorine and sulphate magnesium was used as the feed for the bioreactor in experiment. The concentration range of ammonium and sulphate in the wastewater were kept at 22-27 mgNH4-N/L and 80–130 mg SO4-S/L, respectively. About 80% of the sulphate entering the reactor was removed from the liquid phase, of which 30% appears as S–S2- in the effluent. During sulphate conversion were formation also S-H2S in the biogas and elemental S. Raman spectroscopy (RS) were performed to confirm the presence of sulphur in the sludge. Owing to the reduction sulphate and oxidation ammonium, about 20% nitrogen initially present in the influent was removed appearing as N2 in the gas phase.

Session: 25, Room: A, at Fri, 09/06/2019 - 13:00 to 13:03
Flash presentation in Wastewater treatment

The discovery of anaerobic ammonium oxidation (anammox) revealed the existence of a shortcut in the classic nitrogen cycle where ammonium is converted directly to dinitrogen gas. The anammox process can be used to develop more cost and energy-efficient sustainable nitrogen removal systems comparing to those existing today. However, large-scale applications are limited due to the slow growth rate of anammox bacteria described so far. The UNNOWN project proposes to explore the presence of these bacteria in different ecological niches, and select the appropriate seeding sludge starter as the inoculum for reactors. Anammox biomass is enriched in batch experiments as well as in laboratory scale bioreactor systems, such as Up-flow Biofilter, and Anaerobic Baffled Reactor. Afterwards, microbial community composition, optimum growth conditions, and nitrogen removal efficiency are studied. The ongoing project aims to investigate new anammox bacteria, and the relation between community structure and process activity. Ultimately, it is planned to develop microbial inocula to be used as seeding sources for anammox reactors, and to contribute to a wider
application of anammox process in wastewater treatment.

Session: 25, Room: A, at Fri, 09/06/2019 - 13:03 to 13:06
Flash presentation in Wastewater treatment

In this study, fly ash zeolites (FAZ) of Na-X type were synthesized by alkaline atmospheric aging. FAZ with a specific surface value of 280 m2/g was tested for removal of contaminants from waters in comparison to unconverted FA. The adsorption efficiency of FAZ toward methylene blue from water solutions is over 60 % for the studied concentration levels. The removal efficiency of FAZ toward Cd2+-ions reaches 98 % and it is not affected by the pH from 3.0 to 7.0. The obtained results reveal that FAZ are suitable adsorbents in water remediation systems.

Session: 25, Room: A, at Fri, 09/06/2019 - 12:00 to 12:15
Oral presentation in Wastewater treatment

The combination of constructed wetlands (CWs) and microbial fuel cells (MFCs) has emerged in recent years with the purpose of enhancing wastewater treatment efficiency of CWs while simultaneously generating electricity. Taking the above into account, the aim of this study is to evaluate the influence of MFC integration on organic matter and nutrient removal in a constructed wetland. The results showed that NH4+-N concentration reduced from 66.5 ±9.4 at day 0 (influent) to 4.5±0.4 mg/L and 7.03±3.93mg/L for the integrated system and control system, respectively. In terms of the NH4+-N removal efficiency, an enhancement of the nitrification rate (Ni) was observed when MFC was integrated in VSSF (120.6±1.5 mg/m2 d for control system and 166.8±2.3 mg/m2 d for integrated system). The average COD removal efficiencies were 85.36±2.67% and 94.2±5.9% in the CW and CW-MFC, respectively, obtaining a voltage close to 250 mV. The maximum power density generated was 4.75 mW/m2. In conclusion, the removal efficiencies of COD and NH4+-N in VSSF were 85.4 and 88.4%, respectively, while in CW-MFC were 94.3 and 93.2 %. Therefore, the integrating of a MFC into CW does not have adverse effects on the capacity of the CW to efficiently domestic wastewater treatment.

Session: 25, Room: A, at Fri, 09/06/2019 - 13:06 to 13:09
Flash presentation in Wastewater treatment

An integrated continuous anaerobic–aerobic system has been employed as the treatment for synthetic textile wastewater contained C. I. Acid Red 88 dye. A laboratory scale of upflow anaerobic sludge bed (UASB) flowed by activated treatment was operated at hydraulic residence time (HRT) of 24, 12, 6, and 3 h. the system showed high performance on the removal of color and COD within the HRT ranged between 24 and 6 hrs. At different organic loading rates (OLR), the chemical oxygen demand (COD) removal in the UASB was reached to 86.6% and up to 97% were obtained in the aerobic reactor. The system performance appeared to be more resilient to the inapt decrease in the HRT. The experimental analysis results indicated that the maximum methane yield was 13.2 mmol CH4 g COD-1 d-1 at HRT 6 h, and the system is expected to have a better economic performance under HRT 12 h.

Session: 25, Room: A, at Fri, 09/06/2019 - 12:15 to 12:30
Oral presentation in Wastewater treatment

According to the latest environmental requirements, zero liquid discharge must be considered in all modern manufacturing processes. In principle, solid waste can be achieved only by evaporation plus crystallization, and therefore reverse osmosis is usually applied to decrease the operation expenses by pre-concentrating the evaporator feed.
However, reverse osmosis can generally only achieve concentrates of about 70 to 75 g/kg, still leaving a significant gap before saturation of common salts is reached. Electrodialysis can double this concentration, thus cutting the evaporator operating expenses or even eliminating the evaporator at all, providing the concentrate can be fed directly to crystallization.
In this work, an array of the most common brines was tested on a lab-scale electrodialysis unit, and salt transport, electricity consumption and electric current efficiency was evaluated. No performance drop in either scale-up factor was observed at the maximum concentrations, suggesting that under right operating conditions, integrated membrane processes should significantly decrease the evaporator costs and provide economic feasibility of zero liquid discharge process in waste brine treatment.

Session: 25, Room: A, at Fri, 09/06/2019 - 12:54 to 12:57
Flash presentation in Wastewater treatment

Ozonation was studied as a pretreatment method for a waste biological sludge, contaminated with large amounts of globally used antibiotics; tiamulin, levofloxacin and amoxicillin. At the concentrations of over 100 mg L-1, these antibiotics were found to inhibit biogas production (up to 50%), which means, that the molecules would pass the anaerobic digestion system unchanged. Ozonation of sludge, contaminated with antibiotics, not only removes inhibitory effects, but also improves overall biogas production for 10% or even more, depending on the dose of the oxidant applied in the pretreatment.

Session: 25, Room: A, at Fri, 09/06/2019 - 12:57 to 13:00
Flash presentation in Wastewater treatment