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With the aim of investigating the efficiency of biochar for desalination, experiments with adsorbent treatment at four levels including sesame flour, biochar at temperatures of 400, 500 and 600 ℃ and salt water treatment at four levels including 5, 10, 20 and 35 dS/m were conducted in three replications as a factorial experiment in the form of a completely randomized design in a discontinuous environment. The adsorption of the salinity factor ions was studied in the presence and absence of copper ions. The results showed that the desalination capacity without the presence of copper ions in the best adsorbent (Biochar 600) was obtained at the studied salinities of 411.6 mg/g. While the desalination capacity in the presence of copper ions using the same adsorbent at the studied salinities was 382.2 mg/g, indicating competition between ions and 8.0% decrease in adsorption capacity for salinity 35 dS/m. In both the presence and absence of copper, the highest adsorption was assigned to chlorine and sodium ions and the lowest to potassium ion. In summary, sesame flour biochar, owing to its high active surface area, porous structure, and suitable functional groups on the surface, effectively adsorbs salt ions in the presence of copper ions during the adsorption process.

Recycling salt and water from saline wastewater is crucial for environmental preservation, resource conservation, and social economy sustainability. The heat pump air circulation evaporating separation (HP-ACES) system for saline wastewater treatment is proposed. Nevertheless, it is discovered that the system evaporation efficiency (SEE) is low and solid crystalline salt does not precipitate during the experiment. Therefore, an established and validated mathematical model of the HP-ACES system is provided and the average relative errors of the system evaporation rate (SER) and SEE are 5.3 % and 7 %, respectively. The theoretical analysis of the non-optimized system indicates that the main cause of the low SEE of the HP-ACES system during the test is incorrect cooling water flow. Hence, the system optimization scheme is presented and the comparison of the HP-ACES system's performances before and after optimization is conducted. Results demonstrate that the SEE of the optimized HP-ACES system has been greatly improved (optimized system: 0.62–2.46 kg/kWh, non-optimized system: 0.77–0.91 kg/kWh). Additionally, there is almost no change in the yield and composition of the solid crystalline salt when the inlet air temperature of spray separation tower is above 90 °C.

Bisphenol A, a hazardous endocrine disruptor, poses significant environmental and human health threats, demanding efficient removal approaches. Traditional biological methods struggle to treat BPA wastewater with high chloride (Cl−) levels due to the toxicity of high Cl− to microorganisms. While persulfate-based advanced oxidation processes (PS-AOPs) have shown promise in removing BPA from high Cl− wastewater, their widespread application is always limited by the high energy and chemical usage costs. Here we show that peroxymonosulfate (PMS) degrades BPA in situ under high Cl− concentrations. BPA was completely removed in 30 min with 0.3 mM PMS and 60 mM Cl−. Non-radical reactive species, notably free chlorine species, including dissolved Cl2(l), HClO, and ClO− dominate the removal of BPA at temperatures ranging from 15 to 60 °C. Besides, free radicals, including •OH and Cl2•−, contribute minimally to BPA removal at 60 °C. Based on the elementary kinetic models, the production rate constant of Cl2(l) (32.5 M−1 s−1) is much higher than HClO (6.5 × 10−4 M−1 s−1), and its degradation rate with BPA (2 × 107 M−1 s−1) is also much faster than HClO (18 M−1 s−1). Furthermore, the degradation of BPA by Cl2(l) and HClO were enlarged by 10- and 18-fold at 60 °C compared to room temperature, suggesting waste heat utilization can enhance treatment performance. Overall, this research provides valuable insights into the effectiveness of direct PMS introduction for removing organic micropollutants from high Cl− wastewater. It further underscores the critical kinetics and mechanisms within the PMS/Cl⁻ system, presenting a cost-effective and environmentally sustainable alternative for wastewater treatment.

There is a gradual increase in the discharge of saline wastewater which is harmful to the environment and human health. A novel heat pump air circulation evaporating separation (HP-ACES) system for saline wastewater treatment is proposed and experimentally investigated. The results show that the system evaporation efficiency (SEE) initially decreases before increasing with the expansion valve opening at different refrigerant charges. However, the SER increases by 0.67 kg/h at 1.21 kg refrigerant charge while they descend and then rise at 1.53 and 1.86 kg refrigerant charges. Noted that the effects of expansion valve opening on the SER and SEE are lessened with refrigerant charge. Moreover, there exist the optimal values of total air flow and air flow proportion of packing concentration tower at which the SER and SEE peak, and both of the solution concentration and cooling water flow negatively affect the SER and SEE. Besides, compared with similar evaporating separation systems, the HP-ACES system has higher energy efficiency for treating high saline wastewater and the SEE ranges from 0.86 to 1.64 kg/kWh (5–25 % CaCl2 solution). However, the SEE is low, and it is necessary to reveal the cause and propose the optimization schemes in the future.

Electrocatalytic treatment of chemical saline wastewater showed great technical advantages due to its characteristics of simple operation, high catalytic efficiency and little secondary pollution. The review takes the classification and composition of titanium-based anodes as the starting point. Typical studies of wastewater treatment by electrocatalytic technology based on free radicals and non-free radicals were also discussed. Combined with the previous researches about electrocatalytic mechanisms in recent years, the mechanisms of titanium-based anodes were analyzed in terms of ·OH, active chlorine and others. The studies on titanium-based anodes in chemical wastewater containing different salt concentrations, such as dye wastewater, coal chemical wastewater, landfill leachate wastewater, fertilizer and pesticide production wastewater, etc., were thoroughly examined. According to the amount of electricity required for the removal of organic matter per unit, the energy consumption of titanium-based anodes for wastewater treatment by electrochemistry was described. The review would provide theoretical basis and technical support for electrocatalytic treatment of chemical saline wastewater.

This study investigated a feasible model for treating actual shrimp farm wastewater at a pilot scale that could be applied to farms in the Mekong Delta area. The research was carried out using a hybrid constructed wetlands (HCWs) model, which included a floating constructed wetland (FCW, total area of 1,500 m2) and a horizontal sub-surface constructed wetland (HSCW, total area of 400 m2). The HCWs were cultivated with native plants including: Scirpus littoralis Schrab, Cyperus alternifolius, and Paspalum vaginatum. These plants are all adapted to the high salinity levels of shrimp farm wastewater. The system was operated for 30 days to treat shrimp farm effluent. Results indicated that the model effectively removed organic matter and nitrogen compounds from the wastewater. The treated wastewater had low concentrations of COD (10.0-15.4 mg/L), BOD5 (7.1-12.5 mg/L), NH4+-N (0.04-1.11 mg/L), and TN (0.17-1.83 mg/L), which met the reliable conditions for reuse or safety requirements for discharge to aquatic systems. The findings of this study have significant implications for the sustainable management of shrimp farm wastewater in the Mekong Delta area. The HCWs model is a feasible and effective way to treat this type of wastewater, and it could be adapted to other regions facing similar challenges.

In this research, the exit treated wastewater from the gravity filtration unit, mechanical and chemical treatment unit, biological treatment unit and finally UV disinfection treatment unit enters to a solar desalination unit. Wastewater evaporation process is performed in this unit. In this study, in order to increase the UV waves in solar energy, nano-flooring has been used on the floor of the solar pond. The laboratory results show that the average difference between the experimental data and the theoretical results for simple coating, coating made of zinc oxide nanoparticles and coating made of aluminum oxide nanoparticles is equal to 2%, 2.3% and 1.6%, respectively. Laboratory results show that the average temperature difference between theory and laboratory when simple coating, nano zinc oxide coating and nano aluminum oxide coating are used are 0.5%, 2.89% and 0.67%, respectively. The laboratory results show that the minimum and maximum average temperature of different layers of wastewater are related to the months of January and July, respectively. This research shows that the maximum and minimum temperature difference of the first layer and the last layer of wastewater are in April and March, respectively.

Falling film evaporation technology is widely used in the treatment of salt-containing wastewater in coal chemical industry. However, there is still a lack of research on the inlet method of vertical falling film evaporation tubes. In this paper, the heat and mass transfer processes of saline wastewater under vertical and tangential inlets were investigated using numerical simulations. On this basis, the differences in flow and heat transfer processes between saline wastewater and pure water under tangential inlet were investigated. The results showed that the flow velocity of saline wastewater with a falling film evaporation tube in a tangential inlet mode was larger. Meanwhile, the turbulence in this way was more intense and the fluid temperature in the vertical tube was higher. Saline wastewater has higher temperature and smaller liquid volume fraction than pure water liquid membrane in the range of 193–1,000 mm from the inlet. The use of tangential inlet method to treat salt-containing wastewater has higher evaporation efficiency and is a very effective way to guide the improvement of heat transfer efficiency. HIGHLIGHTS Study on the heat transfer of a falling film evaporator tube with different inlets.; The liquid film velocity at the tangential inlet is faster than that at the vertical inlet.; Salty wastewater is thinner than pure water, which is more conducive to evaporation.;

Abstract This study investigates biological treatment of outlet wastewater from flocculation reactor. This stream has an unpleasant odor. So, a biological treatment unit has been used to separate biological contaminants. Results show that 35 min can be considered as optimum oxygen injection time. Results show that the reduction of nitrate and phosphate is 67% and 60.8% with increasing oxygenation time, respectively. Results show that BOD and COD decrease by about 1.8% and 1% with increasing oxygenation time from 35 to 40 min, respectively. Studies show that organic carbon and petroleum hydrocarbons decrease from 20.1 to 4.8 mg/l and 0.14–0.4 mg/l by increasing oxygen injection time from 5 to 35 min, respectively. Results show that wastewater turbidity decreasing is from 4.3 NTU to 2.1 NTU in biological unit. Results show that range of pH is between 9.9 and 10.4.

Both the flow state of the liquid film and the heat transfer effect all affected the efficiency of falling film evaporation directly. In this study, based on computational fluid dynamics and orthogonal tests, numerical simulations were performed for different inlet velocities, inlet temperatures, and upper and lower tube diameter ratios of evaporation tubes with tangential inlet methods. Results showed that the tangential inlet method makes the liquid film distributed evenly. The increase in the ratio of upper and lower pipe diameters could enhance the heat transfer effect. When it was 1.5:1, the export salt concentration increased to 5.87%. When the inlet velocity increased, the heat transfer effect became better. The inlet temperature had a positive effect on the heat transfer effect. The orthogonal test results showed that when the upper and lower tube diameter ratio was 1.5:1, the inlet flow rates reached 0.4 ​m/s and the inlet temperature was 303 ​K, the flow distance increased by 6.98%.

Solar driven air evaporating separation (AES) technology has extensive application in the field of saline wastewater treatment due to its energy saving and cleanliness. However, these current systems generally utilize solar collectors to heat working fluids (air and wastewater), and then pass these heat carrying fluids into the evaporator to complete the mass transfer evaporation process, so as to realize the separation of the wastewater. This conventional process inevitably leads to the mismatch between heat and mass transfer of two working fluids in evaporator, which limits the efficient utilization of the energy. Accordingly, a novel thermal collector–evaporator integrated unit, in which the collecting process and evaporating process are carried out at the meantime and the collected heat directly supplies the latent heat consumed by this evaporation process, is designed to couple with the solar air evaporating separation system for saline wastewater treatment in this paper. Meanwhile, the system thermodynamic simulation model is established and detailed system performance experimental investigations are carried out. The results show that this system is feasible, and this special design is indeed conducive to improve the system thermal utilization (compared with the traditional system, the average irradiation utilization efficiency ηican be increased by 21.2%). Furthermore, by comparing the experimental and simulation results, the thermodynamic model can effectively predict various system state parameters during operation (errors are all basically within ±10%). More importantly, from the system dynamic characteristic analysis results, the stored wastewater has the phenomenon of heat storage and heat release, which is beneficial to prolong the duration of maintaining high GOR, evaporation efficiency (EE) and system energy utilization efficiency (ηsys). Even under experimental conditions in winter, this system can still sustain high wastewater treatment performance and energy efficiency (When c=10%, three average indicator: GOR = 3.99, EE = 6.97 kg/kWh, ηsys=73.8%).

It was important to establish the scaling mechanism to slow down scaling, which is one of the important problems faced by saline wastewater treatment with falling film evaporators. In this paper, the phase equilibrium data of ternary system NaCl-CaCl2-H2O at 303.15–373.15 K were measured, and the prediction of the flow characteristics and scaling tendency of salt-containing wastewater in the evaporation tube was investigated by numerical simulation based on the phase equilibrium results. The results showed that the mesostable phase diagram of the ternary system was of simple type, and w(NaCl) and w(CaCl2) showed regular variation with temperature when w(NaCl) in the system was 15–28%. Moreover, the components of the four saline wastewaters (10% NaCl + 9, 10, 11, 12% CaCl2) with less salt content had a faster heating and a faster rate of evaporation of the liquid film in the evaporation tube. Based on the solubility in the experiments and simulations, it was concluded that NaCl crystals were precipitated at tube lengths of 718 mm, 942 mm, 966 mm, and 1,000 mm for four salt concentrations in the evaporation process by comparison, and the reliability of the predicted loci was also demonstrated by a falling film evaporation experimental setup. HIGHLIGHTS Creatively predict scaling site based on phase equilibrium and fluid simulation.; Systematic study of multi-temperature phase equilibrium data for ternary systems.; Fine analysis of the flow characteristics of the brine in the evaporation tube.;

It is still one of the significant solutions to treat saline wastewater with thermal desalination technology, especially falling film evaporators. To improve the performance of the falling film evaporator, a numerical study on the gas–liquid two-phase flow characteristics of saline wastewater in the vertical pipe was conducted using the VOF model. The results showed that the inlet velocity of the saline wastewater increased under the same operating conditions, resulting in the thickening of the liquid film and the increase of the average convective heat transfer coefficient. Increasing the inlet temperature of the working liquid reduced the temperature difference, which led to a decrease of the average convective heat transfer coefficient. In addition, as the inlet concentration of the working liquid increased, the film flow rate and the average convective heat transfer coefficient first decreased and then increased slightly. The experimental results verified the accuracy of the numerical simulation, and the average error was 9.27%. HIGHLIGHTS The study of fluid microflow combined with heat transfer was proposed.; The distribution of heat transfer coefficient based on numerical simulation.; The distribution of heat transfer coefficient is correctly verified by experiments.; The effects of the various operating parameters on the heat and mass transfer processes are studied.;

Industrial wastewaters are recognized as a valuable resource, however, their disposal without proper treatment can result in environmental deterioration. The associated environmental/operational cost of wastewater treatment necessitates upgrade of applied processes towards the goals of sustainability and mitigation of climate change. The implementation of cyanobacteria-based processes can contribute to these goals via resources recovery, production of high-value products, carbon fixation and green-energy production. The present study evaluates the cyanobacterium Synechococcus elongatus PCC 7942 (S7942) as a biological component for novel and sustainable alternatives to typical biological nutrient removal processes. Valuable results regarding cultivation temperature boundaries, applied disinfection techniques and analytical methods, as well as regarding relations between parameters expressing S7942 biomass concentration are presented. The results show that at typical industrial wastewater temperatures, S7942 efficiently grew and removed nitrates from treated snack-industry's wastewater. Moreover, in cultures with treated and relatively saline dairy wastewater, its growth rate slightly decreased, but nevertheless nitrates removal rate remained efficiently high. A comparison between typical denitrification processes and the proposed nutrient removal process indicated that a S7942-based system may constitute an alternative or a supplementary to denitrification process. Thus, Synechococcus elongatus PCC 7942 proved to be a potent candidate towards sustainable industrial wastewater treatment applications. HIGHLIGHTS Synechococcus elongatus PCC 7942 efficiently grows in treated industrial wastewater.; High rates of nitrates removal and growth at typical wastewater temperatures.; Efficient growth and high nitrates removal in saline industrial wastewater.; Filtration coupled with chlorination/dechlorination is effective for pre-treatment.;

Concentration followed by electrolysis is one of the most promising ways for saline wastewater treatment, since it could produce H2, Cl2, and an alkaline solution with deacidification potential. However, due to the diversity and difference of wastewater, knowledge on the suitable salt concentration for wastewater electrolysis and the effects of mixed ions are still lacking. In this work, electrolysis experiments of mixed saline water were conducted. The salt concentration for stable dechlorination was explored, with in-depth discussions on the effects of typical ions such as K+, Ca2+, Mg2+, and SO42−. Results showed that K+ had a positive effect on the H2/Cl2 production of saline wastewater through accelerating the mass transfer efficiency in the electrolyte. However, the existence of Ca2+ and Mg2+ had negative effects on the electrolysis performance by forming precipitates, which would adhere to the membrane, reduce the membrane permeability, occupy the active sites on the cathode surface, and also increase the transport resistance of the electrons in the electrolyte. Compared to Mg2+, the damaging effect of Ca2+ on the membrane was even worse. Additionally, the existence of SO42− reduced the current density of the salt solution by affecting the anodic reaction while having less of an effect on the membrane. Overall, Ca2+ ≤ 0.01 mol/L, Mg2+ ≤ 0.1 mol/L and SO42− ≤ 0.01 mol/L were allowable to ensure the continuous and stable dechlorination electrolysis of saline wastewater.

The present study focuses on determining the phyto-treatment efficiency for treatment of moderately saline wastewater using organic raw materials, such as rice husk, coconut husk, rice straw, and charcoal. The moderately saline wastewater with total dissolved solids (TDS) concentration up to 6143.33 ± 5.77 mg/L was applied to the lysimeters at the rate of 200 m3 ha–1 day–1 in five different lysimeter treatments planted with Eucalyptus camaldulensis (T1, T2, T3, T4, and T5). T1 was a control without any filter bedding material, whereas rice straw, rice husk, coconut husk, and charcoal were used as filter bedding materials in the T2, T3, T4, and T5 treatment systems, respectively. Each treatment showed significant treatment efficiency wherein T3 had the highest removal efficiency of 76.21% followed by T4 (67.57%), T5 (65.18%), T2 (46.46%), and T1 (45.5%). T3 and T4 also showed higher salt accumulation, such as sodium (Na) and potassium (K). Further, the pollution load in terms of TDS and chemical and biological oxygen demand significantly reduced from leachate in the T3 and T4 treatments in comparison with other treatments. Parameters of the soil, such as electrical conductivity, exchangeable sodium percentage, and cation exchange capacity did not show values corresponding to high salinity or sodic soils, and therefore, no adverse impact on soil was observed in the present study. Also, Eucalyptus camaldulensis plant species showed good response to wastewater treatment in terms of growth parameters, such as root/shoot weight and nitrogen, phosphorus, and potassium (NPK) uptake, plant height, biomass, and chlorophyll content. Root and shoot dry weight were in the order T3 (51.2 and 44.6 g)>T4 (49.3 and 43.5 g) > T5 (47.6 and 40.5 g) > T2 (46.9 and 38.2 g) > T1 (45.6 and 37.1 g). Likewise, the total chlorophyll content was highest in T3 (12.6 μg/g) followed by T4 (12.3 μg/g), T5 (11.9 μg/g), T2 (11.5 μg/g), and the control, that is, T1 (11.0 μg/g). However, the most promising results were obtained for T3 and T4 treatments in comparison with the control (T1), which implies that, among all organic raw materials, coconut and rice husks showed the highest potential for salt accumulation and thereby wastewater treatment. Conclusively, the findings of the study suggest that organic raw material–based amendments are useful in managing the high salts levels in both plants and leachates.

Abstract Significant rise in concentration of saline wastewater entering the treatment plants has been resulting in many problems in the biological treatment processes. On the other hand, the specific conditions of physicochemical treatment methods for saline and hyper saline wastewater have limited their application on a large-scale. Over the past few decades, Sequencing Batch Reactor (SBR) process has been widely used as an efficient, well-designed and practical approach for treatment of domestic and industrial wastewater due to its cost-effectiveness and simplicity. SBR Performance can enhance by providing simultaneous suspended and attached growth of microorganisms which act as a hybrid growth. In this study, a lab-scale Hybrid Sequencing Batch Reactor (HSBR) with 6.4 l working volume was used to examine the effect of salinity (NaCl), increased from 0 to 6.7% (g NaCl/ L wastewater), on the biological treatment. Therefore, COD, MLSS, MLVSS and SVI parameters have been measured over a period of 7 months of operation. The operational parameters namely pH, dissolved oxygen (DO) and temperature were 7.5–8.5, 1.5–6.8 mg /L and 20–25 °C respectively during whole experiment. Influent COD of synthetic wastewater was maintained at 650 ± 25 mg/L. The HSBR Cycle time including, influent feeding, React, Settling and effluent discharge were 1/20/1/1 h respectively. Results indicated that by increasing salt concentration from 0 to 67.7 g NaCl/L, the COD removal efficiency reduced from 94.22 to 53.69%. Moreover, as the NaCl concentration increased, MLSS rose up to 69%, while MLVSS almost stayed constant and SVI dropped by 83%. The results indicated that the simultaneous use of suspended and attached growth of microorganisms and gradual increasing of salt content of wastewater could lead to greater biomass concentration and ultimately improvement in the degradation of organic matter. Besides, settling performance and its velocity were noticeably improved by increasing salinity.

Metal wastewater and saline wastewater are two major problems in the field of wastewater treatment. At present, common treatment methods include ion exchange, electrodialysis and reverse osmosis. The ion exchange method often uses chemical reagents to achieve regeneration, which is likely to cause secondary pollution after treatment. Electrodeionization technology can continuously operate to treat wastewater, and does not require the use of acid-base reagents to achieve resin regeneration, but the structure is complex and requires higher pretreatment. Bipolar membrane electro-regenerative ion exchange is a new technology that has been practically applied in water supply treatment by a certain enterprise. A considerable degree of ion exchange capacity, after reaching the exchange capacity, the bipolar membrane is used for water dissociation to achieve electrical regeneration of the membrane. On the basis of investigating the desalination and regeneration of groundwater (well water) by this technology, this paper studies its removal effect on simulated food processing salty wastewater, Cu2+ and Fe2+ containing simulated electroplating rinsing wastewater. Influence of operating conditions such as influent flow on the treatment effect.

Saline wastewater is known to affect the performance of phosphate-accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) process. However, studies comparing the effect of salinity on different PAO clades are lacking. In this study, ‘Candidatus Accumulibacter phosphatis’ Clade I and II (hereafter referred to as PAOI and PAOII) were highly enriched (∼90% in relative abundance as determined by quantitative FISH) in the form of granules in two sequencing batch reactors. Anaerobic and aerobic batch experiments were conducted to evaluate the effect of salinity on the kinetics and stoichiometry of PAOI and PAOII. PAOI and PAOII communities showed different priority in using polyphosphate (poly-P) and glycogen to generate ATP in the anaerobic phase when exposed to salt, with PAOI depending more on intracellular poly-P degradation (e.g., the proportion of calculated ATP derived from poly-P increased by 5–6% at 0.256 mol/L NaCl or KCl) while PAOII on glycolysis of intracellularly stored glycogen (e.g., the proportion of calculated ATP derived from glycogen increased by 29–30% at 0.256 mol/L NaCl or KCl). In the aerobic phase, the loss of phosphate uptake capability was more pronounced in PAOII due to the higher energy cost to synthesize their larger glycogen pool compared to PAOI. For both PAOI and PAOII, aerobic conversion rates were more sensitive to salt than anaerobic conversion rates. Potassium (K+) and sodium (Na+) ions exhibited different effect regardless of the enriched PAO culture, suggesting that the composition of salt is an important factor to consider when studying the effect of salt on EBPR performance.

Background: High concentration of salt makes biological treatment impossible due to bacterial plasmolysis. The present research studies the process of electrochemical oxidation efficiency and optimal levels as important factors affecting pH, salt concentration, reaction time and applied voltage. Methods: The sample included graphite electrodes with specifications of 2.5 cm diameter and 15 cm height using a reactor with an optimum capacity of 1 L. Sixty samples were obtained with the aid of the experiments carried out in triplicates for each factor at 5 different levels. The entire experiments were performed based on standard methods for water and waste water treatments. Results: Analysis of variance carried out on effect of pH, salt concentration, reaction time and flow intensity in elimination of chemical oxygen demand (COD) showed that they are significant factors affecting this process and reduce COD with a coefficient interval of 95% and test power of 80%. Scheffe test showed that at optimal level, a reaction time of 1 hour, 10 g/L concentration, pH = 9 and 15 V electrical potential difference were obtained. Conclusion: Waste waters containing salt may contribute to the electro-oxidation process due to its cations and anions. Therefore, the process of electrochemical oxidation with graphite electrodes could be a proper strategy for the treatment of saline wastewater where biological treatment is not possible.

Paper discuses changes in utilization rate of Low Molecular Weight polycyclic aromatic hydrocarbons PAHs in sequencing bath reactors (SBR) operating with flocked and aerobic granular activated sludge. Studies were carried out in laboratory scale SBR reactors filled with model wastewater characterized by salinity at level 4.00 g·dm−3. Wastewater inflowing to laboratory reactors was characterized by varying biological oxygen demand (BOD) load in the range of 0.05−1.60 kg BOD·kg−1·d−1.

Background and purpose:Moving Bed Biofilm Reactor is an aerobic attached growth with better biofilm thickness control, lack of plugging and lower head loss. Consequently, this system is greatly used by different wastewater treatment plants. High TDS wastewater produced petrochemical, leather tanning, sea food processing, cannery, pickling and dairy industries. The aim of this study was to evaluate the performance of MBBR in saline wastewater treatment. Materials and methods: In this study, 50 percent of a cylindrical reactor with 9.5 liter occupied media with 650 m2.m-3. In the first step, hydraulic regime was evaluated and startup reactor was done by sanitary sludge. Bio film was generated with glucose as the sole carbon source in synthetic wastewater. MBBR performance evaluation was performed in 6:30 and 8:45 with saline wastewater after bio film produced on media. Results: After 83 days of passing MBBR operation with saline wastewater containing 3000-12000 mg.L-1 TDS, organic loading rate of 2.2-3.5 kg/m3.d COD removal efficiency reached 80-92%. Conclusion: Moving bed biofilm reactor is effective in organic load elimination from saline wastewater.

Development of nitrification biomass that is growing attached on carried material was examined by measuring its ammonium or nitrit oxidation rates. Porous ceramic rings (36 pieces) were put into the fixed bed reactor (FBR ). The fixed bed reactor that was operated continuously for more than 500 day was continued to be operated at a HRT of 1 day, a DO of above 5 mg L-1 and pH of 8. Ammonia concentration in the feeding was 50 mg NH4+-N L-1. At days 1, 5, 12, 20, 33 and 50, six porous ceramic rings were taken out and then ammonia and nitrite removal rate by biofilm in the ceramic rings was separately measured. The measurement of rates was done in small cylindrical glass reactors with initial concentration of ammonia and nitrite was 10 mg N L-1. Until 50 days of incubation AORs were always higher than NORs. Additionally, ammonia oxidizers attach or grow faster in the porous ceramic material than nitrite oxidizers.

In order to find the optimal design characteristics of constructed wetlands for saline wastewater treatment, halotolerant microorganisms, isolated from the water of the Sečovlje salterns, were inoculated into the media of a pilot-scale constructed wetland (CW). The purpose of this study was to examine the influence of different salinities on the efficiency of halotolerant microorganisms for the removal of pollutants in order to evaluate the possibility of their employment for saline wastewater treatment. The efficiency of ammonium removal (34.1 %) was the highest with 0 % NaCl in wastewater and slightly lower (31.8) when 2 g/dm3 saccharose was added to aerated 1.5 % NaCl wastewater. The highest removal efficiency of chemical oxygen demand (COD) in the pilot-scale subsurface flow (SSF) CW was 83.6 % when saccharose (2 g/dm3) was added to aerated 1.5 % NaCl wastewater. It was found that removal efficiency of the pilot-scale constructed wetland with inoculated halo-tolerant microorganisms showed a higher sensitivity to aeration and the presence of saccharose than to variation of the salinity of the wastewater. It can be concluded that halotolerant microorganisms, isolated from the Sečovlje salterns, are not sensitive to the changes in salinity and are, therefore, an alternative in the treatment of saline wastewater with a constructed wetland. However, with aeration their efficiency could be further improved.