AcknowledgementsFinancial supports by the Ministry of Science and Technology and the Environmental Protection Administration, Taiwan under grant nos. MOST100-2221-E-002-256-MY3 and 102-EPA-F-001-001 are appreciated. The opinions expressed in this paper are not necessarily those of the sponsors. The authors also thank the anonymous reviewers for their valuable comments and suggestions that greatly improve the quality of this paper.
AD, Cy3 NHS ester digestion; SI, wastewater treatment plant sludge-based inoculum; MI, manure-based inoculum; DCF, diclofenac; TCS, triclosan; NP, nonylphenol; FISH, fluorescence in situ hybridization; VFA, volatile fatty acids; TS, total solids; VS, volatile solids; PPCPs, pharmaceuticals and personal care products; IC50, 50% inhibition
Biomethanation; IC50; PPCPs; Toxicity; Xenobiotics
Pharmaceuticals and personal care products (PPCPs) are considered to be emerging contaminants (micropollutants). These micropollutants have been reported in domestic wastewater, surface and ground water, animal slurry, and soil  and . In wastewater treatment plants (WWTP), most of these micropollutants are partially adsorbed to the suspended solids and removed with the particles contained in the primary and secondary sludge . These sludges are typically used as substrates in anaerobic reactors. Additionally, many of these micropollutants are used in the livestock industry and through the animal slurry they end up in the manure-based anaerobic reactors  and . The adverse impacts of all the micropollutants on the manure-based AD reactors are not clear yet.
Main physicochemical characteristics LBH 589 raw DWTS.Analytes (Units)RangeMean ± SDAnalytes (Units)RangeMean ± SDTemperature (°C)19.7–20.420.4 ± 0.8VSS/TS (%)26.7–38.531.2pH6.99–8.377.60 ± 0.54sCOD/TCOD (%)2.87–4.243.72TS (g L−1)1.33–2.131.57 ± 0.22sCOD in supernatant (mg L−1)10.53–12.0411.43 ± 0.56VSS (g L−1)0.39–0.600.49 ± 0.07Proteins in supernatant (mg L−1)0.23–0.400.37 ± 0.05TCOD (mg L−1)298–331307 ± 10Polysaccharide in supernatant (mg L−1)10.10–14.4611.82 ± 1.30Note: SD means standard deviation. Number of measurements (n): for temperature and pH, n = 5; for total solids (TS), suspended solids (SS), volatile suspended solids (VSS), total chemical oxygen demand (TCOD), sCOD, proteins and polysaccharide, n = 10.Full-size tableTable optionsView in workspaceDownload as CSV
As mentioned above, ammonia removal performance was similar to that AZD1283 of TOC. The removal efficiencies of ammonia were maintained above 90%, with average effluent concentrations both below 0.2 mg L−1. However, TN removal efficiencies declined after operation for 2 months in phase II, which was mainly attributed to the deficiency of carbon source because few nutrients released from P. communis. Meanwhile, the removal efficiencies of organics in both reactors increased to above 70%. It is well accepted that using plant as carbon sources for denitrification is economic and effective. However, the addition of plant carbon sources may introduce secondary pollution because of the unstable and uneven releasing of nutrients. It has been reported that some kinds of organics are not suitable to be used to denitrification ( Gibert et al., 2008), even caused some harmful effects, such as incomplete nitrogen removal (mixture of wood chips, shredded bark and topsoil; willow wood chips), nitrogen releasing (mixture of wood chips, shredded bark and topsoil; willow wood chips), excessive reduction of nitrate to ammonium rather than nitrogen gas (compost obtained from the biological decomposition, organic wastes of wood trimmings, leaves, rotten vegetables and food scraps) ( Gibert et al., 2008), nitrite accumulation (glucose and methanol) ( Srinandan et al., 2012). However, the addition of P. communis did not cause these problems.
From Day 74, the TP removal efficiency slightly decreased because the influent was shifted to the synthetic wastewater. From Day 74 to Day 120, the average TP removal efficiencies in AES and ANS were 50.70% and 87.34%, and the average final concentration was 3.19 mg L−1.
3.5. FK-228 variations and sulfate generation
The pH value and SO42− concentration in SIBPD were illustrated in Fig. 6. From Day 1 to Day 6, the pH of influent was 7.04–7.12, however, the pH in Effluent A (7.14–7.46) was slightly higher than influent.
Fig. 6. pH variation and sulfate concentration of SIBPD.Figure optionsDownload full-size imageDownload as PowerPoint slide
After Day 7, the pH in Effluent A began to gradually decrease, decreased to 7.01 on Day 59, indicated that the aerobic nitrification became the main reaction taken place in AES and alkalinity would be consumed in the nitrification process.
The pH value in influent was 7.45–7.57 during the real wastewater period from Day 60 to Day 73. Accordingly, the pH of Effluent A varied from 7.13 to 7.38, whereas the pH in Effluent B was always above 7.
2.4. Cyclic voltammetry
Cyclic voltammetry (CV) was performed using an electrochemical workstation (CHI 660D, Chenhua, Shanghai) equipped with three-electrode system. An Ag/AgCl electrode was used as the reference electrode, the anode as the counter electrode, and the cathode as the working electrode. Cyclic voltammograms were recorded at 55 °C or 30 °C at MG 262 low scanning rate of 2 mV/s.
2.5. Enzyme activity measurement
Dehydrogenase activity (DHA) was measured using triphenyl tetrazolium chloride (TTC) as a terminal proton acceptor as previously described (She et al., 2006). One DHA unit (U) was defined as the production of 1 μg of TPF per hour, and DHA was defined as U per milligram of protein (U/mg protein).
The activity of ATPase was determined as described by Zhang et al., 2014a and Zhang et al., 2014b and reported as U/mg protein, with one ATPase unit (U) defined as the production of 1 μmol of phosphorus from the decomposition of ATP. The protein content was measured using the Lowry method (Lowry et al., 1951).
Fig. 7. Comparison of bubble velocity between experiment and calculation by drift flux model with Kawahara et al.’s distribution parameter for 3-pyr-Cytisine test channel with σA = 0.51. (a) Upstream channel (b) Downstream channel.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 8. Comparison of bubble velocity between experimental data and numerical data by simulation with VOF method.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 9. Comparison of bubble shape between experiments and numerical results by VOF method (Nitrogen – HFE-7200 two-phase flows in the net secondary productivity (NSP) test channel with contraction of σA = 0.35.) (a) jL,d = 0.43 m/s, jG,d = 0.27 m/s (b) jL,d = 0.43 m/s, jG,d = 0.67 m/s.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 10. Dimensionless bubble length data plotted against gas–liquid volume flow rate ratio. (a) Upstream channel (b) Downstream channel.Figure optionsDownload full-size imageDownload as PowerPoint slide
Communication between companies is found to be another barrier preventing the expansion of a wider use of FA (Ammenberg et al., 2014). Ammenberg et al. (2014) also underlines the relevance of creating industrial symbioses when the aim is to reduce CO2 emissions in the industry. Because of the nature of the industrial processes involved, cement industry has the versatility of trading multiple flows of material and BAY-X 1005 from and to other industries that also seek collaborations.
At a worldwide scale, portland cement represents more than 80% of the total cement produced, in spite of proven alternatives that carry additional economic benefits and less environmental burden. This demonstrates that the whole industry experiences a narrow perception on the outcomes derived from the use of FA making it difficult to migrate into a more suitable direction (Jug, 2007). Technical limitations such as concrete curing become a challenge when using FA cements. Reports indicate that long-term compression strengths are directly dependent on precise curing techniques of concretes containing FA (Helmuth, 1987 and Mehta, 1985). Batching companies and individual users are often reluctant to incorporate these techniques, generally because these require additional time, resources and costs.