The Current Adoption of Dry-Direct Seeding Rice (DDSR) in Thailand and Lessons Learned for Mekong River Delta of Vietnam

The paper documents the joint study trip, organized by CCAFS Southeast Asia for Vietnamese rice researchers, extension workers, as well as local decision makers, to visit Thailand in April 2018. The goal of the study trip was to observe and learn the experience of Thai farmers on the large-scale adoption process of dry-direct seeding rice (DDSR), a viable alternative to address regional scarcity of fresh water in irrigation caused by the drought and salinity intrusion in the Mekong River Delta

Effect of sponge volume fraction on the performance

A novel fluidized bed bioreactor (FBBR) was designed by integration of anaerobic granular activated carbon and aerobic sponge reactors. This FBBR was evaluated at different sponge volume fractions for treating a synthetic wastewater. Polyester urethane sponge with cube size of 1 × 1 × 1 cm and density of 28-30 kg/m3 with 90 cells per 25 mm was used as biomass carrier. The results indicate that the FBBR could remove more than 93% of dissolved organic carbon (DOC). The highest nutrient removal efficiencies (58.2% PO4 -P and 75.4% NH4-N) were achieved at 40% sponge volume fraction. The system could provide a good condition for biomass growth (e.g. 186.2 mg biomass/g sponge). No significant different performance in specific oxygen uptake rate was observed between 30, 40, and 50% sponge volume fractions. © IWA Publishing 2013 Water

Pilot scale study on a new membrane bioreactor hybrid system in municipal wastewater treatment

A pilot scale membrane bioreactor hybrid system (MBR-HS) was evaluated for municipal wastewater treatment. This novel system comprised of a granular activated carbon-sponge fluidized bed bioreactor (GACS-FBBR) followed by a submerge membrane bioreactor (MBR) with the capacity of 2L/min. The results indicated that the MBR-HS could effectively remove 90% DOC and 95% NH4-N. PO4-P removal efficiency was remained stable at about 70% throughout the experiment. Specific oxygen uptake rate (SOUR) of activated sludge increased from 0.72 to 2.21mg O2/gVSSh for the first 10days and then followed by a steady stage until the end of experiment. Sludge volume index (SVI) was always below 50mL/g, demonstrated an excellent settling properties of sludge. The system also showed an achievement in terms of low trans-membrane pressure (TMP) development rate. The TMP increasing rate was only 0.65kPa/day, suggesting GACS-FBBR can be a promising pre-treatment for MBR. © 2013 Elsevier Ltd

A new combined inorganic-organic flocculant (CIOF) as a performance enhancer for aerated submerged membrane bioreactor

In this study, a new combined inorganic-organic flocculant (CIOF) of FeCl3 and membrane performance enhancer (MPE50) was prepared and added to an aerated submerged membrane bioreactor (SMBR). The effects of CIOF on the performance of an aerated submerged membrane bioreactor (SMBR) were evaluated. The results indicated that the SMBR with CIOF addition could remove almost 100% total phosphate while eliminating over 90% ammonia (NH 4-N) and dissolved organic carbon (DOC) during an 80-day of operation. The respiration tests revealed that the specific oxygen uptake rate (SOUR) was stable around 1.5-2.0 mg O2/gMLVSS h. The sludge volume index (SVI) of less than 100 mL/g during the operation showed the importance of CIOF on the improvement of settling properties of the sludge. Soluble carbohydrate concentration was also well correlated with DOC of the supernatant. CIOF was successful in the reduction of fouling of membrane as the membrane was only chemically cleaned after 53 days of operation. © 2010 Elsevier B.V. All rights reserved

The effects of biomass parameters on the dissolved organic carbon removal in a sponge submerged membrane bioreactor

A novel sponge submerged membrane bioreactor (SSMBR) was developed to effectively remove organics and nutrients from wastewater. Sponge is introduced within the SSMBR as a medium for the attached growth of biomass. This paper evaluates the effects of new and acclimatized sponges for dissolved organic carbon (DOC) removal from wastewater at different mixed liquor suspended solids (MLSS) concentration of the sludge. It was observed in a series of experimental studies that the acclimatized sponge performed better than the new sponge whilst the optimum DOC removal could be achieved at 10g/L of MLSS with the acclimatized sponge. Moreover, the paper analyses the relationships between the MLSSsponge/MLSSsludge and the DOC removal efficiency of SSMBR. The results showed a non-linear relationship between the biomass parameters of the sponge and the sludge, and the DOC removal efficiency of SSMBR. A second-order polynomial function could reasonably represent these relationships

Multicriteria assessment of advanced treatment technologies for micropollutants removal at large-scale applications

© 2016 Elsevier B.V. With the introduction and discharge of thousands of new micropollutants (MPs) every year, traditional water and wastewater treatment plants may be incapable of tackling them all. With their low concentrations and diversity in nature, MP removal encounters numerous challenges. Although some MPs are effectively eliminated via conventional treatment methods, most of them can easily escape and are retained in the discharged effluent. Therefore, advanced methods such as (i) adsorption, (ii) oxidation and advanced oxidation processes (O3 and O3-based advanced oxidation processes, UV/H2O2), (iii) membrane processes, and (iv) membrane bioreactors, become an inevitable approach. Despite the unsurprisingly vast number of papers on MP treatment available at present, most of these studies were carried out at a laboratory scale while only a few pilot- and full-scale studies have experimented. Nevertheless, an in-depth assessment of real-world MP treatment methods is extremely crucial for practitioners. To date, no paper has been dedicated to look at this issue. Therefore, this paper aims to review these large-scale treatment methods. First, the paper goes through the regulations and standards which deal with MPs in water courses. It will then assess these methods in various case-studies with reference to different criteria towards serving as a reference for further practical applications

Effect of Tris-(hydroxymethyl)-amino methane on microalgae biomass growth in a photobioreactor

© 2016 Elsevier Ltd. One of the buffers namely Tris (Tris-(hydroxymethyl)-amino methane) was used to increase the growth of microalgae by stabilizing the pH value in microalgae cultures. The objective of this research is to determine the growth rate and biomass productivity of Chlorella sp. with and without Tris addition. Both conditions function at various N:P ratios cultured in photobioreactors (carbon dioxide of 5% (v/v), light intensity of 3.3 Klux). Daily variations in nutrient removal (nitrogen and phosphorus), cell concentration, DO, temperature and pH were measured for data analysis. The results show that the largest yield of biomass was achieved at the N:P ratio of 15:1 with and without Tris. After cultivation lasting 92 h, the algae concentration at this ratio was 1250 mg L-1 and 3568 mg L-1 with and without Tris, respectively. This indicates that adding Tris to the photobioreactor greatly reduces algae biomass due to bacterial competition

A new sponge tray bioreactor in primary treated sewage effluent treatment

The new attached growth sponge tray bioreactor (STB) was evaluated at different operating conditions for removing organics and nutrients from primary treated sewage effluent. This STB was also assessed when using as a pre-treatment prior to micro-filtration (MF) for reducing membrane fouling. At a short hydraulic retention time (HRT) of 40min, the STB could remove up to 92% of DOC and 40-56% of T-N and T-P at an organic loading rate (OLR) of 2.4kg COD/m3 spongeday. This OLR is the best for the STB as compared to the OLRs of 0.6, 1.2 and 3.6kg COD/m3 spongeday. At 28mL/min of flow velocity (FV), STB achieved the highest efficiencies with 92% of DOC, 87.4% of T-P, and 54.8% of T-N removal. Finally, at the optimal OLR and FV, the STB could remove almost 90% of organic and nutrient, significantly reduce membrane fouling with HRT of only 120min. © 2010 Elsevier Ltd

Effects of sponge size and type on the performance of an up-flow sponge bioreactor in primary treated sewage effluent treatment

The effects of polyurethane sponge size and type on the performance of an up-flow sponge bioreactor were studied using different sponge cube sizes (1 × 1 × 1 cm, 2 × 2 × 2 cm and 3 × 3 × 3 cm) and types of sponge (S28-30/45R, S28-30/60R, S28-30/80R and S28-30/90R). The reactors were operated under anaerobic conditions in an early stage and an aerobic condition in a latter stage. The results indicate that there was no significant difference in the organic and nutrient removal rates between sponge types. The medium size sponge (2 × 2 × 2 cm) had the best performance in terms of both biomass growth and pollutants removal. Under anaerobic condition, the COD, TN and TP removal efficiencies were up to 70%, 45% and 55%, respectively, and significantly improved under aerobic conditions (e.g. >90% TOC, 95% COD, 65% TN and 90% TP). The external biomass grew faster under anaerobic conditions while internal biomass was dominant under aerobic condition. © 2009 Elsevier Ltd

Removal of antibiotics in sponge membrane bioreactors treating hospital wastewater: Comparison between hollow fiber and flat sheet membrane systems

© 2017 Elsevier Ltd Hollow fiber (HF) and flat sheet (FS) Sponge MBRs were operated at 10–20 LMH flux treating hospital wastewater. Simultaneous nitrification denitrification (SND) occurred considerably with TN removal rate of 0.011–0.020 mg TN mg VSS−1 d−1. Furthermore, there was a remarkable removal of antibiotics in both Sponge MBRs, namely Norfloxacin (93–99% (FS); 62–86% (HF)), Ofloxacin (73–93% (FS); 68–93% (HF)), Ciprofloxacin (76–93% (FS); 54–70% (HF)), Tetracycline (approximately 100% for both FS and HF) and Trimethoprim (60–97% (FS); 47–93% (HF). Whereas there was a quite high removal efficiency of Erythromycin in Sponge MBRs, with 67–78% (FS) and 22–48% (HF). Moreover, a slightly higher removal of antibiotics in FS than in HF achieved, with the removal rate being of 0.67–32.40 and 0.44–30.42 µg mg VSS−1 d−1, respectively. In addition, a significant reduction of membrane fouling of 2–50 times was achieved in HF-Sponge MBR for the flux range