Polluted Surface Water Treatment Research Articles

Pea grain shells as a raw material for sorptive treatment of polluted waters

In the complex processing of pea grain, as well as in the production of groats and flour, a number of wastes are generated, a significant part of which is utilized. The conversion of waste processing to secondary raw materials not only allows for the resolution of environmental problems but also expands the opportunities for raw materials in economic sectors. Pea grain shells, which contain biopolymers, vitamins and minerals, can be considered as one of the sources of raw materials for obtaining sorption materials. The object of the research in this work was the shells isolated from the grain of the Amior and Temp pea varieties of Russian selection. The aim of the study was to investigate the structure, physical properties, and component composition of the pea grain shells, as well as to evaluate the prospects of their use as raw materials for the production of sorbents for the treatment of polluted surface water and wastewater. To determine the quality indicators of pea grain shells, the generally accepted methods were used. The share of shells in pea grain was found to be 7.1-10.6%. The main components in the composition of pea grain shells are polysaccharides, with a predominance of fiber, largely determining the structure and properties of this raw material. Pea grain shells are characterized by low density, good hygroscopicity and moisture retention capacity. The proteins and pectins present in the composition of the pea shells have sorption properties. It is possible to increase the degree of purification of surface and waste water from harmful impurities by using extracts from pea shells containing biopolymers that form insoluble complexes with pollutants.

Fixed-bed biofilter for polluted surface water treatment using chitosan impregnated-coconut husk biochar

Pelletizing biochar enables its use as a biofilter medium for polluted canal water treatment. Coconut husk biochar pellets and their modification with chitosan (CHC) were compared with conventional activated carbon pellets and gravel. The biofilter columns with these media were operated with a hydraulic loading rate of 0.1 m3/m2∙h. CHC showed the highest potential to reduce phosphate and nitrogen, via the adsorption process in the first week of filtration and later enhanced by biodegradation, to achieve removal efficiencies of 61.70 and 54.37% for these two key nutrients, respectively, over five weeks of biofilter operation. The predominant bacteria in the biofilter communities were characterized at the end of the experiments by next generation sequencing and quantitative polymerase chain reaction analysis. The biofilter communities included ammonium oxidizing, nitrite oxidizing, denitrifying, polyphosphate accumulating and denitrifying phosphate-accumulating bacteria that benefit nutrient removal. The CHC biofilter also effectively removed micropollutants, including pharmaceuticals.

Binary coagulation system (graphene oxide/chitosan) for polluted surface water treatment

In this study, chitosan (CS) is used as a natural coagulant aid alongside graphene oxide (GO) to remove turbidity and numerous pollutants from raw and artificially contaminated surface water. The coagulation capability of the system (GO/CS) was assessed with respect to a water sample's turbidity, pH, coagulant dose, settling velocity, and temperature. The presence of CS enhanced the coagulation capacity of GO at varied pH levels and no GO residue was detected in the water after the treatment. The proposed system achieved high turbidity removal efficiency (≥98.3%) for all turbidity levels. A mixture of GO (8 mg/L) and CS (2 mg/L) was ideal to remove algae (99.5%) and bacteria (≥95.0%). Furthermore, it demonstrated a high coagulation capacity to remove dyes, direct brown-2 (DB-2), methylene blue (MB), and Pb(II) ions from artificially contaminated surface water. Interestingly, the sludge exhibited an extraordinary adsorption capacity for DB-2, MB, and Pb(II) ions. The adsorption process followed the pseudo-second-order kinetic model, and was consistent with the Langmuir model, with an adsorption capacity of up to 667.8, 400.7, and 459.1 mg/g for DB-2, MB, and Pb(II) ions, respectively. Therefore, the presented binary coagulation system is of great potential economic value for the treatment of raw surface water and wastewater.

Orbitrap mass spectrometry for the molecular characterization of water resource recovery from polluted surface water using membrane bioreactor

The increasing organic contamination of surface water hinders the conventional tap water treatment process. Membrane bioreactors (MBRs) are a promising alternative technology for recovering water from polluted surface water. In this study, the composition changes of dissolved organic matters (DOMs) in MBR and ultraviolet/ozone (UV/O3)-MBR systems for polluted surface water treatment were investigated using Orbitrap mass spectrometry analysis with unknown screening. The intense DOM ions within a mass-to-charge ratio range of 100–500 was detected, and 2340 molecular formulae from 5743 peaks were assigned to the two systems. The most abundant components were formulae with C, H, O, N, and CHO only classes. The highest formulae decrease including CHO, CHON, CHOS, and CHONS were attributed to the bio-carrier used in both systems. Results showed that bioprocess was the main contributor in the DOM reduction, and the integration of UV/O3 into the MBR improved the DOM composition changes. Biodegradable components with low O/C ratio in the CHO and CHON classes remarkably increased in the UV/O3-MBR system. The integration of UV/O3 as a polishing step in the recirculation stream of MBR system was effective in improve the DOM removal.

Endogenous respiration process analysis between aMBR and UV/O3-aMBR for polluted surface water treatment

Abstract The microbial endogenous respiration process is very important in biological water treatment processes. This study analyzed and compared the endogenous respiration process in an attached growth membrane bioreactor (aMBR) system and a UV/O3 integrated aMBR system (UV/O3-aMBR) in treating polluted surface water with CODMn around 10 mg/L. The endogenous respiration activity of heterotrophic microbes and autotrophic nitrifiers activity in both systems was analyzed and compared. Results show that heterotrophic bacteria and autotrophic nitrifiers enter endogenous respiration at 6 h aeration in an aMBR and 0 h in a UV/O3-aMBR system. Biomass amount on PVA-gel in aMBR was higher than in UV/O3-aMBR in terms of specific respiration rates SOURt, SOURH, and SOURA. Substrate remained on PVA-gel in the aMBR system, but no substrate remained on PVA-gel in the UV/O3-aMBR system. Higher species of microbes, including recoverable and irrecoverable components, existed in the aMBR system as compared to the UV/O3-aMBR system. The UV/O3-aMBR system could make full use of the advanced oxidation process (AOP) and biological process, leading to a higher treatment performance, and has the potential to mitigate total energy demand. Thus, the UV/O3-aMBR system can be used as a new technology for treating polluted surface water with the co-contribution of biological process and AOP treatment.

Two-stage constructed wetland systems for polluted surface water treatment

Two pilot scale wetland systems were studied for the removal of organics, nitrogen, phosphorus and coliform from polluted surface water. Each system consisted of two units: a vertical flow (VF) wetland packed with construction materials gravel, brick or organic sugarcane bagasse, followed by a surface flow (SF) or floating treatment (FT) wetland. All wetland units were planted with Phragmites. The wetland systems were operated under constant and shock hydraulic load (HL) periods. Input COD, N, P loadings ranged between 61 and 2181, 7–1040, 2–194 g/m2d, respectively across first stages of each system. Mean removal percentages ranged between 39 and 97, 11–83, 20–100% and 4–85, 16–86, 1.4–100% across first and second stage wetlands, respectively. Mass balance analyses revealed ≤7% N and ≤14% P accumulation in plants; as such, microbial and adsorption kinetics controlled removal dynamics. Nitrification was the limiting nitrogen removal factor in first stage wetlands; organic carbon was supplied by the employed media. Aerobic organics removal and nitrification were diminished during initial stage of shock load periods. In contrast, second stage SF and FT wetlands showed stable removal performances under similar conditions. Resuspension of settled particles decreased removal performance in second stage wetlands, as shock periods progressed toward final stage. Coliform mortality was increased in second stage wetlands. Physico-chemical properties of brick materials in construction material based VF wetland and hanging root volume inside the water column of FT wetland supplemented removal performance. In general, this study provides evidence on potential application of constructed wetlands for polluted surface water treatment.

A Study to Assess the Effectiveness of Constructed Wetland Technology for Polluted Surface Water Treatment

Abstract: The study aims to assess the applying effectiveness of constructed wetland technology for polluted surface water treatment. The experimental models were operated with 2 hydraulic loadings of 500mL/min/m2 (T1) and 1500mL/min/m2 (T2). The reed grass (Phragmites australis) was selected for the studying process. The surface water resource was removed from the pollutant components (TSS, BOD5, COD) and harmful microorganisms (fecal coliform) which aim to protect the water quality and aquatic ecosystems. The results showed the treatment effectiveness of loading of 500mL/min/m2 is higher than the loading of 1500mL/min/m2, especially in the reed planting trial. In particular, the treatment efficiency of pollutants such as TSS, BOD5, COD reached a high rate of 85%, 90%, and 87%, respectively. In addition, ANOVA statistical analysis showed the effectiveness of water quality parameters belong to two loadings were statistically significant (P<0.05). Thus, the surface water pollutant removal by subsurface vertical flow constructed wetland technology could be contributed to promoting the sustainable agricultural development.
 Keywords: Constructed wetland, removal, surface water, Phragmites australis, pollution.

Anaerobic ammonium-oxidizing bacteria in river water treatment wetland

Anaerobic ammonium-oxidizing (anammox) bacteria play an essential part in nitrogen removal in constructed wetlands. The objective of the present study was to explore the spatiotemporal dynamics of anammox bacterial communities and the associated factors in a full-scale constructed wetland for the treatment of polluted surface water. The abundance and diversity of anammox bacterial communities were characterized using quantitative polymerase chain reaction (PCR) and clone library analysis, respectively. Anammox bacterial diversity, richness, and abundance in the treatment wetland differed considerably among sampling sites and seasons, whereas anammox bacterial community structure tended to change slightly with site and time. Anammox abundance was likely influenced by temperature and the contents of nitrate and nitrite nitrogen. The increase of carbon and nitrogen contents could lower wetland anammox bacterial diversity and richness. Moreover, anammox bacterial diversity, richness, and abundance were also affected by wetland vegetation type. Candidatus Brocadia dominated in the treatment wetland, whereas Candidatus Kuenenia and a novel anammox phylotype were also detected. This work could provide some new insights towards anaerobic ammonium oxidization in surface water treatment wetland.

Treatment of polluted surface water with nylon silk carrier-aerated biofilm reactor (CABR)

Carrier aerated biofilm reactor (CABR) with nylon silk as the biofilm growth carrier was constructed to treatment of polluted surface water, which could improve the practical application in comparison with MABR process. The results show that CABR process can effectively improve the self-purification capacity of the polluted surface water, efficient removal of COD and NH3-N, making water quality achieve the level V of Environmental Quality Standards for Surface Water (GB 3838-2002, China). Modified nylon silk can alter the community structures and increase bacteria during CABR process operation. Large pore size of nylon silk leads to the formation of special biofilm structure in CABR. Extracellular polymer (EPS) and membrane fouling resistance distribution indicated that the nylon silk fouling control ability of CABR reactor is much higher than that of membrane-aerated biofilm reactors (MABR). The results show that the CABR process can effectively purify surface water and improve the practical application.

Nitrogen and phosphorus removal comparison between periphyton on artificial substrates and plant-periphyton complex in floating treatment wetlands.

Artificial substrates (ASs) and floating treatment wetlands (FTWs) have been widely used in the treatment of polluted surface water. In fact, periphyton on ASs functions in nutrient removal, while the plant-periphyton complex functions in FTWs. However, the nutrient removal performance of the periphyton on ASs and the plant-periphyton complex in FTWs has not been systematically compared. Thus, ASs and FTWs were established in a mesocosm experiment to compare nitrogen and phosphorus removal between the two ecological treatment techniques. The results showed that the total nitrogen removal efficiency was 60.4% in the AS treatments and 65.3% in the FTWs, while the total phosphorus removal efficiency was 83.7% in the AS treatments and 39.45% in the FTWs. Periphyton on the ASs absorbed 2.5g Nm-2 and 0.85g Pm-2, accounting for 20.8% of the N removal and 18.7% of the P removal. Sedimentation contributed to 71.3% of the N removal and 56.1% of the P removal in the AS treatments. For the plant-periphyton complex in the FTWs, 25.1% of the N and 53.0% of the P accumulated in plant tissue. Most of the reduced N (47.1%) was removed by other pathways, which was likely the effect of periphyton attached on plant roots and floating rafts. The nutrient removal efficiencies and pathways of AS and FTW treatments showed different characteristics, providing a reference for the selection of treatment measures for polluted surface water remediation.

A Pilot‐Scale Diatomite Membrane Bioreactor for Slightly Polluted Surface Water Treatment

In the Huai River basin in China, seasonal pollution, especially excess ammonia nitrogen (NH4+‐N), threatens the water quality. This study investigates the performance of a pilot‐scale diatomite membrane bioreactor (DE‐MBR) for treating slightly polluted surface water (Huai River). Removal efficiencies for the chemical oxygen demand (CODMn), NH4+‐N, and turbidity, as well as the molecular weight (MW) of the raw water, mixed liquor and effluent, particle size of the bio‐diatomite, trans‐membrane pressure (TMP) of the system, and microscopic characteristics of the membrane, are monitored for 135 days. The results shows that (1) with the diatomite addition of 4 g L−1, the DE‐MBR contributes to significant removals of CODMn and NH4+‐N; (2) the TMP increases at an average rate of 0.04 kPa/day during the running period; (3) the MW distributions and natural organic matter fraction demonstrates that a significant increase of biopolymers occurs in the mixed liquor; (4) the highest removal rate of the charged hydrophilic acids indicates that aromatic proteins are more likely to be removed by the DE‐MBR compared to humic‐like substances; and (5) microscopic observations shows that hydrophobic micromolecular organics are the main contributors leading to hydraulically irreversible membrane fouling.

Performances study of UV/O3-aMBR recirculation system in treating polluted surface water

This study used UV/O3-aMBR system for treating polluted surface water with CODMn around 10 mg/L, to improve the removal of non-biodegradable components. UV/O3 was used in the recirculation stream, partially treating the recalcitrant in aMBR permeate to improve its biodegradability, and then send back to aMBR for biodegradation. Removal performance of UV/O3-aMBR system with recirculation ratio 20, 40, 60 and 80% was tested and compared. The removal of CODMn, UV254 and NH3-N increased with the increment of recirculation ratio. UV/O3-aMBR system has higher recalcitrant removal performance and less membrane fouling. The fluorescent dissolved organic matter (FDOM) was largely reduced in UV/O3-aMBR system, and the system hydrophilicity was higher than aMBR system. The Modified Stover Kincanoon model was able to describe UV/O3-aMBR system; and has higher Umax than aMBR system. UV/O3-aMBR can be develop as an effective technology in improving recalcitrant removal in polluted surface water treatment.

Pilot scale treatment of polluted surface waters using membrane-aerated biofilm reactor (MABR)

ABSTRACTThe increasing threat to human health and aquatic life caused by nitrogen pollution in surface waters requires critical attention. The membrane-aerated biofilm reactor (MABR) is a promising alternative compared to conventional technologies. In this work, a pilot-scale MABR system was employed to treat polluted surface water in continuous-flow mode. The nitrogen removal performances with the variations of the aeration parameters, hydraulic loading and C/N ratio were explored. The results showed that intra-membrane pressure plays a dominant role in improving the denitrification rate. The nitrification dynamics of the MABR system were favoured in conditions of low influent C/N ratios and hydraulic loading, but limit the denitrification process due to insufficient carbon source. A counter optimal hydraulic loading of 0.016 m3/(m2 day) (hydraulic retention time of 36 h), and a corresponding increase in the influent C/N ratio was beneficial for nitrogen removal. When the influent C/N ratio was raised to a factor of 8, the total organic carbon (TOC), ammonium and total nitrogen (TN) removal efficiency could reach 80.0%, 92.2% and 60.3%, respectively. This indicated that the MABR has a potential to remove TN by simultaneous nitrification and denitrification (SND) in polluted surface water treatment.

Optimization of magnetic-seeding coagulation in artificially polluted surface water treatment by response surface methodology

Artificially polluted surface water was treated using magnetic-seeding coagulation, with polyaluminum chloride (PAC) as the coagulant and a ferromagnetic material as the magnetic seed (MS). A novel approach using a combination of response surface methodology (RSM) and the Box–Behnken design (BBD) was employed to evaluate the effects and interactions of four main factors, the dosages and dosing points of PAC and MS. The three response variables selected to evaluate the effectiveness of the treatment were supernatant turbidity removal rate, floc size, and floc strength. The optimal operating conditions were obtained by constraining the three desirable responses using Minitab software. The PAC and MS dosages (22.7 mg/L and 0.6 g/L) and their dosing points (1.5 and 1.2 min) were determined to be the optimum conditions for the maximum turbidity removal rate, floc size, and floc strength of 98.0%, 154.7 μm, and 57.8%, respectively. Confirmation experiments demonstrated that such a combination of RSM and BBD was a powerful and effective approach for optimizing the magnetic-seeding coagulation. Additionally, zeta potential analysis indicated that the MS decreases the negative charge of pollutants and acts as a coagulating core during coagulation.

Spatiotemporal variation of bacterial and archaeal communities in a pilot-scale constructed wetland for surface water treatment

Microorganisms play important roles in the reduction of organic and inorganic pollutants in constructed wetlands used for the treatment of polluted surface water. However, the diversity and structure of microbial community in surface water constructed wetland system remain poorly known. The present study was made to characterize bacterial and archaeal communities in a surface water constructed wetland using Illumina high-throughput sequencing. The diversity and structure of both bacterial and archaeal communities illustrated a remarkable spatiotemporal variation. Archaeal communities showed lower richness and diversity than bacterial communities. Bacterial diversity decreased with increasing wetland layer depth. A variety of bacterial phyla or candidate divisions were found in wetland bacterial communities, including Proteobacteria, Chloroflexi, Firmicutes, Acidobacteria, Bacteroidetes, Nitrospirae, Actinobacteria, Spirochaetae, Planctomycetes, Chlorobi, Deferribacteres, Cyanobacteria, OP8, WS3, TA06, and OP11, while Proteobacteria, Chloroflexi, and Firmicutes were the major bacterial groups. Euryarchaeota and Thaumarchaeota dominated wetland archaeal communities.

Practice of integrated system of biofilter and constructed wetland in highly polluted surface water treatment

To find an appropriate process for highly polluted surface water, an integrated system with a double-layer biofilter and a constructed wetland was developed. In the biofilter packed with carbon-rich ceramic granules, alternation of nitrification and denitrification was realized resulting in prominent TN (total nitrogen) removal. The constructed wetland was designed in subsurface flow mode with 0.15m depth filled with calcium-rich ceramic granules, which improved phosphorus removal greatly. COD (chemical oxygen demand), TN, NH4+-N and TP (total phosphorus) in the final effluent were mostly below 30, 15, 5 and 0.5mg/L, respectively. The overall phosphorus removal rate in the constructed wetland reached 158.9g/m2year, in which granules’ interception and plants’ uptake respectively contributed 74.7% and 25.3%. After one year’s operation, the calcium content on the surface of the granules in the constructed wetland decreased obviously, whereas phosphorus content increased greatly.

Engineering application of membrane bioreactor for wastewater treatment in China: Current state and future prospect

China has been the forerunner of large-scale membrane bioreactor (MBR) application. Since the first large-scale MBR (⩾ 10 000 m3·d−1) was put into operation in 2006, the engineering implementation of MBR in China has attained tremendous development. This paper outlines the commercial application of MBR since 2006 and provides a variety of engineering statistical data, covering the fields of municipal wastewater, industrial wastewater, and polluted surface water treatment. The total treatment capacity of MBRs reached 1 × 106 m3·d−1 in 2010, and has currently exceeded 4.5 × 106 m3·d−1 with ∼75% of which pertaining to municipal wastewater treatment. The anaerobic/anoxic/aerobic-MBR and its derivative processes have been the most popular in the large-scale municipal application, with the process features and typical ranges of parameters also presented in this paper. For the treatment of various types of industrial wastewater, the configurations of the MBR-based processes are delineated with representative engineering cases. In view of the significance of the cost issue, statistics of capital and operating costs are also provided, including cost structure and energy composition. With continuous stimulation from the environmental stress, political propulsion, and market demand in China, the total treatment capacity is expected to reach 7.5 × 106 m3·d−1 by 2015 and a further expansion of the market is foreseeable in the next five years. However, MBR application is facing several challenges, such as the relatively high energy consumption. Judging MBR features and seeking suitable application areas should be of importance for the long-term development of this technology.

Test Study on Combined Process of <i>Clarification-Adsorption-Membrane Separation</i> for Chemical Agent VX Polluted Surface Water Treatment

t developed test devices and carried out test adopting combined process of clarification-adsorption-membrane separation targeted at surface water which was polluted by chemical agent VX. Investigation on purification effects of sand filtration, microfiltration, ultrafiltration, activated carbon adsorption and reverse osmosis was implemented in sections. It also researched on working principles of each section. Furthermore, comparative study has been made for adsorption performance of coaly granular activated carbon and that of shell activated carbon. The results show that the combined process can remove effectively simulation agent in water and the outlet quality complies with requirements of relevant standards.

Study on the erosion rate of powdered activated carbon in raw water aqueduct

Growing interest in using Powdered Activated Carbon (PAC) in raw water aqueduct, as a method of polluted surface water treatment, raises the question of transport of PAC in the aqueduct, which is related to the potential PAC erosion along the aqueduct. By means of a recently developed re-circulating flume, erosion rates of PAC with the grain size of 230 meshes (less than 62 μm) depending on shear stress and bulk density were the discussed with real-time measurement of suspended PAC concentration. Lateral cross sectional averaging shear stress was decided by the actual value in the raw water conveying aqueduct of upstream Huangpu River, Shanghai, China, smaller than 1.8 N·m−2. As for the bulk density, it was measured with compacting times varying from 1 d to 15 d, equivalent to 1 550 kg/m3–1 800 kg/m3. Experiments were conducted for the shear stress and bulk density separately, so as to isolate and quantify the effects of one of the parameters. The results demonstrate that, for a particular PAC particle, the erosion rate increases with shear stress and decreases with bulk density as a function of power form. A product of powers of the lateral cross sectional averaging shear stress and bulk density to estimate PAC erosion rate is presented by approximating experimental data sets.

High concentration powdered activated carbon-membrane bioreactor (PAC-MBR) for slightly polluted surface water treatment at low temperature

In this study, different concentrations of PAC combined with MBR were carried out to treat slightly polluted surface water (SPSW) at low temperature (10°C). Effects of PAC on the efficiencies of operation, treatment, and the performance of the process were investigated. It was found that the effluent quality, performance efficiency, resistance of shock load were all enhanced and chemical irreversible membrane fouling was reduced with increasing dosage of PAC in MBR. Only when the concentration of PAC which acted as biological carriers was high enough (i.g., 50g/L), nitrification without initial inoculation in the filtration tank could start within 19days and be completed within 35days at 10°C. Fifty grams per liter PAC was the optimal dosage in MBR for stable and extended operation. Under this condition, mean removal efficiencies of ammonia nitrogen (NH3-N), dissolved organic carbon (DOC) and UV254 were 93%, 75%, and 85%, respectively.