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Simultaneous recovery of calcium phosphate granules (CaP granules) and methane from vacuum collected black water (BW), using an upflow anaerobic sludge blanket (UASB) reactor was previously investigated. It was calculated that only 2% of the total phosphorus (P) fed was present as CaP granules whereas 51% of the P accumulated dispersed in the reactor, limiting the applicability of this process for recovery of phosphate. This study proposes adding calcium to increase the P accumulation in the reactor and the production of CaP granules. Calcium was added in a lab-scale UASB reactor fed with BW. An identical UASB reactor was used as reference, to which no calcium was added. The treatment performance was evaluated by weekly monitoring of influent, effluent and produced biogas. Sludge bed development and CaP granulation were assessed through particle size analysis. The composition and structure of CaP granules were chemically and optically assessed. Calcium addition increased accumulation of P in the reactor and formation and growth of granules with size > 0.4 mm diameter (CaP granules). Moreover, with calcium addition, CaP granules contained 5.6 ± 1.5 wt% of P, while without calcium a lower P content was observed (3.7 ± 0.3 wt%). By adding Ca, 89% of the incoming P from BW accumulated in the reactor and 31% was sampled as CaP granules (> 0.4 mm diameter). Addition of 250 mgCa L −1 of BW was the optimum loading found in this study. Furthermore, no significant reduction in COD Total removal (> 80%) and CH 4 production (0.47 ± 0.10 gCOD-CH 4 g −1 COD Total -BW) was observed. Therefore, adding calcium can significantly increase the CaP granulation without inhibiting the simultaneous CH 4 recovery. This further indicates the potential of this process for phosphate recovery. [ABSTRACT FROM AUTHOR]

This work studied the anaerobic sludge filtration capacity for pathogens reduction in a 29 L and 1.65 m height lab-scale UASB reactor treating domestic wastewater at low temperatures in the city of Puno (Peru). The anaerobic sludge filtration capacity was performed applying upflow velocities of 0.12, 0.14, 0.16, 0.20, 0.27 and 0.41 m/h. Results show that the HE removal varied between 89 and 95% and the most common specie was Ascaris lumbricoides . Faecal coliform and Escherichia coli removal varied in the range of 0.9–2.1 and 0.8–1.6 log 10 respectively. Likely related to the low operational temperatures, the total COD removal varied between 37 and 62%. The best performance in terms of removal of HE, total COD and turbidity was obtained at the lowest upflow velocity of 0.12 m/h. In order to meet WHO standards for water reuse a post-treatment unit will be required to polish the effluent. [ABSTRACT FROM AUTHOR]

Removal of 14 pharmaceuticals and 3 of their transformation products was studied in a full-scale source separated sanitation system with separate collection and treatment of black water and grey water. Black water is treated in an up-flow anaerobic sludge blanket (UASB) reactor followed by oxygen-limited autotrophic nitrification–denitrification in a rotating biological contactor and struvite precipitation. Grey water is treated in an aerobic activated sludge process. Concentration of 10 pharmaceuticals and 2 transformation products in black water ranged between low μg/l to low mg/l. Additionally, 5 pharmaceuticals were also present in grey water in low μg/l range. Pharmaceutical influent loads were distributed over two streams, i.e. diclofenac was present for 70% in grey water, while the other compounds were predominantly associated to black water. Removal in the UASB reactor fed with black water exceeded 70% for 9 pharmaceuticals out of the 12 detected, with only two pharmaceuticals removed by sorption to sludge. Ibuprofen and the transformation product of naproxen, desmethylnaproxen, were removed in the rotating biological contactor. In contrast, only paracetamol removal exceeded 90% in the grey water treatment system while removal of other 7 pharmaceuticals was below 40% or even negative. The efficiency of pharmaceutical removal in the source separated sanitation system was compared with removal in the conventional sewage treatment plants. Furthermore, effluent concentrations of black water and grey water treatment systems were compared with predicted no-effect concentrations to assess toxicity of the effluent. Concentrations of diclofenac, ibuprofen and oxazepam in both effluents were higher than predicted no-effect concentrations, indicating the necessity of post-treatment. Ciprofloxacin, metoprolol and propranolol were found in UASB sludge in μg/g range, while pharmaceutical concentrations in struvite did not exceed the detection limits. [ABSTRACT FROM AUTHOR]

A laboratory plant consisting of two UASB reactors was used for the treatment of industrial wastewater from the wheat starch industry. Several load tests were carried out with starch wastewater and the synthetic substrates glucose, acetate, cellulose, butyrate and propionate to observe the impact of changing loads on gas yield and effluent quality. The measurement data sets were used for calibration and validation of the Anaerobic Digestion Model No. 1 (ADM1). For a precise simulation of the detected glucose degradation during load tests with starch wastewater and glucose, it was necessary to incorporate the complete lactic acid fermentation into the ADM1, which contains the formation and degradation of lactate and a non-competitive inhibition function. The modelling results of both reactors based on the modified ADM1 confirm an accurate calculation of the produced gas and the effluent concentrations. Especially, the modelled lactate effluent concentrations for the load cases are similar to the measurements and justified by literature. [ABSTRACT FROM AUTHOR]

Abstract: Recovery of phosphorus from wastewater as calcium phosphate could diminish the need for mining of scarce phosphate rock resources. This study introduces a novel approach to phosphorus recovery by precipitation of calcium phosphate granules in anaerobic treatment of black water. The granules formed in the Upflow Anaerobic Sludge Blanket (UASB) reactor at lab- and demonstration-scale were analyzed for chemical composition and mineralogy by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), Electron microprobe (EMP), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and micro X-ray Diffraction (XRD). The granules had a diameter of 1–2 mm, organic content of 33 wt%, and phosphorus content of 11–13 wt%. Three calcium phosphate phases were identified in the granules: hydroxyapatite, calcium phosphate hydrate and carbonated hydroxyapatite. Without any addition of chemicals, 7 gP/person/year can be recovered with the calcium phosphate granules, representing 2% of the incoming phosphorus in the UASB reactor. As the heavy metal content was lower compared to other phosphorus recovery products, phosphate rock and phosphorus fertilizer, the calcium phosphate granules could be considered as a new phosphorus product. [Copyright &y& Elsevier]

Abstract: The UASB process among other treatment methods has been recognized as a core method of an advanced technology for environmental protection. This paper highlights the treatment of seven types of wastewaters i.e. palm oil mill effluent (POME), distillery wastewater, slaughterhouse wastewater, piggery wastewater, dairy wastewater, fishery wastewater and municipal wastewater (black and gray) by UASB process. The purpose of this study is to explore the pollution load of these wastewaters and their treatment potential use in upflow anaerobic sludge blanket process. The general characterization of wastewater, treatment in UASB reactor with operational parameters and reactor performance in terms of COD removal and biogas production are thoroughly discussed in the paper. The concrete data illustrates the reactor configuration, thus giving maximum awareness about upflow anaerobic sludge blanket reactor for further research. The future aspects for research needs are also outlined. [Copyright &y& Elsevier]

Abstract: The performance of high-loaded anaerobic ammonium oxidizing (ANAMMOX) upflow anaerobic sludge bed (UASB) reactors was investigated. Two ANAMMOX reactors (R1 with and R2 without effluent recycling, respectively) were fed with relatively low nitrite concentration of 240 mg-N L−1 with subsequent progressive increase in the nitrogen loading rate (NLR) by shortening the hydraulic retention time (HRT) till the end of the experiment. A super high-rate performance with nitrogen removal rate (NRR) of 74.3–76.7 kg-N m−3 day−1 was accomplished in the lab-scale ANAMMOX UASB reactors, which was 3 times of the highest reported value. The biomass concentrations in the reactors were as high as 42.0–57.7 g-VSS L−1 with the specific ANAMMOX activity (SAA) approaching to 5.6 kg-N kg-VSS−1 day−1. The high SAA and high biomass concentration were regarded as the key factors for the super high-rate performance. ANAMMOX granules were observed in the reactors with settling velocities of 73–88 m h−1. The ANAMMOX granules were found to contain a plenty of extracellular polymers (ECPs) such as 71.8–112.1 mg g-VSS−1 of polysaccharides (PS) and 164.4–298.2 mg g-VSS−1 of proteins (PN). High content of hemachrome (6.8–10.3 μmol g-VSS−1) was detected in the ANAMMOX granules, which is supposed to be attributed to their unique carmine color. [ABSTRACT FROM AUTHOR]

Feasibility of grey water treatment in an upflow anaerobic sludge blanket (UASB) reactor operated at different hydraulic retention time (HRT) of 16, 10 and 6h and controlled temperature of 30°C was investigated. Moreover, the maximum anaerobic biodegradability without inoculum addition and maximum removal of chemical oxygen demand (COD) fractions in grey water were determined in batch experiments. High values of maximum anaerobic biodegradability (76%) and maximum COD removal in the UASB reactor (84%) were achieved. The results showed that the colloidal COD had the highest maximum anaerobic biodegradability (86%) and the suspended and dissolved COD had similar maximum anaerobic biodegradability of 70%. Furthermore, the results of the UASB reactor demonstrated that a total COD removal of 52–64% was obtained at HRT between 6 and 16h. The UASB reactor removed 22–30% and 15–21% of total nitrogen and total phosphorous in the grey water, respectively, mainly due to the removal of particulate nutrients. The characteristics of the sludge in the UASB reactor confirmed that the reactor had a stable performance. The minimum sludge residence time and the maximum specific methanogenic activity of the sludge ranged between 27 and 93 days and 0. 18 and 0. 28kg COD/(kgVSd). [Copyright &y& Elsevier]

Abstract: Effect of natural ionic polymer additives on granulation in lab-scale UASB reactors treating low-strength synthetic wastewater (COD 750–850mg/L) was examined. The organic loading rate was 1.477±0.118kgCOD/m3/day. Under identical conditions four similar reactors were operated in parallel with the following additives: control with no additive, anionic part of Reetha (Sapindus trifoliata) extract, cationic part of Reetha extract, and Chitosan. By the end of the study period, Chitosan as an additive produced largest granules with mean size of 0.15mm closely followed by the cationic fraction of the Reetha extract with mean size of 0.144mm, and anionic fractions of the Reetha extract with 0.139mm. Control reactor with no additives had the smallest size granules with mean size of 0.128mm. The fraction of granules in the sludge bed of size >0.1mm showed similar trend. The largest granule size observed in the reactors with additives was 4–5mm as compared to 2mm in the control reactor. Cationic polymers were more effective additives for enhancing sludge granulation. Exo-cellular protein, lipid, sugar and total polymer increased with granulation in the reactors. A COD removal efficiency of 95–98% was achieved in all the reactors. [Copyright &y& Elsevier]

Abstract: Acid Orange 7 (AO7) was treated anaerobically under fed-batch and continuous conditions. Fed-batch assays carried out with and without cosubstrate showed that the removal rate of this dye is highly favourable when glucose is added as cosubstrate. In addition, some intermediates generated after the reductive breakdown of AO7, such as 1-amino-2-naphthol (1A2N), seem to play a significant role as redox mediators, thus increasing the degradation rate of the dye. This effect is evidenced by the fact that, during the first feeding, the maximum AO7 removal rate was achieved after a lag phase, whereas for further AO7 feedings this phase was not observed. This can be explained by the presence of 1-amino-2-naphthol in the medium. During the continuous treatment with UASB reactors, AO7 loading rates of 1.7mMd−1 (590mgl−1 d−1) were achieved, with 92% AO7 removal efficiencies, operating with an influent comprised of AO7 (0.58mM) and glucose (2gl−1). In addition, when the cosubstrate was limiting (AO7 0.3mM and glucose 0.25gl−1), AO7 removal was significantly lower (78%). [Copyright &y& Elsevier]

The effect of NaCl on thermophilic (55°C) methanol conversion in the presence of excess of sulfate (COD/SO42−=0.5) was investigated in two 6.5 L lab-scale upflow anaerobic sludge bed reactors inoculated with granular sludge previously not adapted to NaCl. Methanol was almost completely used for sulfate reduction in the absence of NaCl when operating at an organic loading rate of 5 g COD L−1 day−1 and a hydraulic retention time of 10 h. The almost fully sulfidogenic sludge consisted of both granules and flocs developed after approximately 100 days in both reactors. Sulfate reducing bacteria (SRB) outcompeted methane producing archaea (MPA) for methanol, but acetate represented a side-product, accounting for maximal 25% of the total COD converted. Either MPA or SRB did not use acetate as substrate in activity tests. High NaCl concentrations (25 g L−1) completely inhibited methanol degradation, whereas low salt concentrations (2.5 g NaCl L−1) provoked considerable changes in the metabolic fate of methanol. The MPA were most sensitive towards the NaCl shock (25 g L−1). In contrast, the addition of 2.5 g L−1 of NaCl stimulated MPA and homoacetogenic bacteria. [Copyright &y& Elsevier]

The effect of the specific gas loading rate on the acidifying, sulfate reducing and sulfur removal capacity of thermophilic (55°C; pH 6.0) granular sludge bed reactors treating partly acidified wastewater was investigated. A comparison was made between a regular UASB reactor and a UASB reactor continuously sparged with N2 at a specific gas loading rate of 30 m3 m−2 d−1. Both UASB reactors (upflow velocity 1.0 m h−1, hydraulic retention time about 5 h) were fed a synthetic wastewater containing starch, sucrose, lactate, propionate and acetate and a low sulfate concentration (COD/SO42− ratio of 10) at volumetric organic loading rates (OLR) ranging from 4.0 to 49.8 gCOD l−1 reactor d−1. Immediately after imposing an OLR of 25 gCOD l−1 reactor d−1, the acidification and sulfate reduction efficiency dropped to 80% and 30%, respectively, in the UASB reactor. Both efficiencies recovered slowly to 100% during the course of the experiment. In the N2 sparged reactor, both the acidification and sulfate reduction efficiency remained 100% following the OLR increase to 25 gCOD l−1 reactor d−1. However, the sulfate reduction efficiency gradually decreased to about 20% at the end of the experiment. The biogas (CO2 and CH4) production rate in the UASB was very low, i.e. <3 l biogas l−1 reactor day−1, resulting in negligible amounts (<20%) of H2S stripped from the reactor liquid. The total H2S concentration of the N2 sparged UASB reactor effluent was always below 25 mg l−1, but incomplete sulfate reduction kept the maximal H2S stripping efficiency below 70%. [Copyright &y& Elsevier]