芦苇生态湿地系统处理造纸废水的探讨

根据造纸污水的特点,在科学详细地分析、评价、论证了现有造纸污水处理技术的基础上,从滨州市的实际情况出发,充分分析了应用湿地生态技术处理造纸污水的可行性,对造纸企业实现环保与经济双赢具有很好的指导作用.     

Emergy evaluation of an integrated livestock wastewater treatment system

Wastewater treatment practices should pay more attention to their environmental performances due to their resources consumption and emissions’ impact. While reclaimed water reuse seems to have become a promising practice, is it always feasible in any condition? To address this issue, this study carried out an extended emergy evaluation of a holistic wastewater treatment system. On one hand, this method was extended to include the emissions’ impact. On the other hand, this study integrated a wastewater treatment plant, its excess sludge disposal system and treated water disposal system into an integrated wastewater treatment system (IWTS), so as to evaluate its performances more completely. And then several indicators, including cost per unit pollutant eliminated (CUPE), ratio of positive output (RPO), environmental load ratio (ELR), and sustainability index (SI), were proposed for evaluating the performances of an IWTS. Two scenarios (scenario A: wastewater treatment + sludge landfilling + treated water discharges; scenario B: wastewater treatment + sludge landfilling + reclaimed water reuse) for a livestock wastewater treatment plant in Sichuan Agricultural University located in Ya’an City in Southwest China, as cases, were researched. The results show that scenario B has lower positive output efficiency and greater environmental load than scenario A. Meanwhile, the reclaimed water reuse raises cost per unit pollutant eliminated compared with the treated water being discharged directly; emissions’ impact enhances the environmental load of the two scenarios to different degree; emissions’ impact has decisive effect on the sustainability of the two scenarios. These results mean that the reclaimed water reuse should not be advocated in this case. This study provides some policy implications: (1) wastewater treatment process should be comprehensively evaluated from its resources consumption and impact of emissions; (2) reclaimed water reuse should be carefully evaluated from its pros and cons simultaneously; (3) the local conditions should be considered when implementing reclaimed water reuse, such as local water body conditions, market demands, the related laws and regulations, corporations’ economic conditions, etc.     

Nitrogen recovery in an integrated system for wastewater treatment and tilapia production

An integrated system, consisting of Up-flow Anaerobic Sludge Blanket (UASB)-duckweed-tilapia ponds was used for recovery of sewage nutrients and water recycling. A UASB reactor with 40 liter working volume was used as pre-treatment unit followed by a series of three duckweed ponds for nitrogen recovery. The treated effluent and duckweed biomass was used to feed fishponds stocked with Nile tilapia (Oreochromis niloticus). The UASB reactor was fed with raw, domestic sewage at 6 h hydraulic retention time. The three duckweed ponds were stocked with Lemna gibba and fed with UASB effluent at 15 days hydraulic retention time. Nitrogen recovery from UASB effluent via duckweed biomass represented 81% of total nitrogen removal and 46.5% from the total nitrogen input to the system. In subsequent fishponds the nitrogen recovery from duckweed as fish feed was in the range of 13.4–20%. This nitrogen in fish biomass represented 10.6–11.5 g N from the total nitrogen in the raw sewage fed to the UASB reactor. The growth performance of tilapia (Oreochromis niloticus) showed specific growth rates (SGR) in the range of 0.53–0.97. The range of feed conversion ratio (FCR) and protein efficiency ratio (PER) were 1.2–2.2 and 2.1–2.28, respectively. The results of the experiments showed total fish yield and net fish yield in the range of 17–22.8 ton/ha/y and 11.8–15.7 ton/ha/y respectively. In conclusion UASB-duckweed-tilapia ponds provide marketable by-products in the form of duckweed and fish protein, which represent a cost recovery for sewage treatment.     

Biomass production for bioenergy using recycled wastewater in a natural waste treatment system

Bioenergy production from biomass is proposed as a method to solve part of the nation's energy problem. However, biomass and bioenergy production is questioned as an environment-friendly approach due to the potential increase of water pollution and the potential decrease of available water resource. A conceptual model of an integrated natural waste treatment system that produces biogas and biomass for bioenergy, treat waste and wastewater, conserve fresh water, and decrease the potential water pollution is presented. The potential biomass production from water hyacinth, duckweed, cattail, and knotgrass was investigated using recycling wastewater from an integrated natural waste treatment system from 2005 to 2008. Although the biomass production from recycling wastewater was not controlled for maximum production, this research identified the large potential impact that could be made if these systems were implemented. The overall average water hyacinth growth rate was high to 0.297 kg wet wt./m²/day during a research period of over 500 days, including both the active and non-active growing seasons. The average daily growth rates of duckweed, cattail, and knotgrass were 0.099-0.127, 0.015, and 0.018 kg wet wt./m², respectively. This research illustrated that water hyacinth was a more promising aquatic plant biomass for bioenergy production when wastewater effluent was recycled as water and nutrient sources from an integrated natural waste treatment system.     

Performance of an overland flow system for advanced treatment of wastewater plant effluent

Overland flow (OF) systems were evaluated and compared for advanced treatment of municipal and industrial effluents, including nutrients and nondegradable chemical oxygen demand (COD) removal. Three pilot plants were constructed at the Shahin Shahr Wastewater Treatment Plant (WWTP), Isfahan, Iran. Each pilot was assigned a specific wastewater and all were simultaneously operated for 8 months. Treatment of primary effluent, activated sludge secondary effluent, and lagoon effluent of textile wastewater was investigated at application rates (ARs) of 0.15, 0.25, and 0.35m(3)m(-1)h(-1). During 5 months of stable operation after a 3-month acclimation period, mean removals of total 5-day biochemical oxygen demand (TBOD(5)), total COD (TCOD), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP) and turbidity were 74.5%, 54.8%, 66.2%, 39.4%, 35.8%, and 67.7% for primary effluent; 52.9%, 52.9%, 66.5%, 44.4%, 39.8%, and 50.1% for activated sludge effluent; 65.7%, 58.7%, 70.3%, 41.7%, 41.3%, and 54.9% for textile wastewater lagoon effluent, respectively. The model of Smith and Schroeder, 1985. Field studies of the overland flow process for the treatment of raw and primary treated municipal wastewater. Journal of Water Pollution Control Federation 57, 785-794] was satisfactory for TBOD(5). For all treatment parameters a standard first-order removal model was inadequate to represent the data but a modified first-order model provided a satisfactory fit to the data. Based on the results of this study, it can be concluded that an OF system as advanced treatment had the ability to meet effluent discharge permit limits and was an economical replacement for stabilization ponds and mechanical treatment options.     

Ultrasound effects on the activity of Aspergillus niger lipases in their application in dairy wastewater treatment

We evaluated the effect of ultrasound radiation on lipase activity. The experiments were conducted using a low‐cost crude enzyme extract. We then used this lipase to treat dairy effluent. The results of our study presented an increase of approximately 430% in the concentration of free fatty acids.     

Winery wastewater treatment using the land filter technique

This study outlines a new approach to the treatment of winery wastewater by application to a land FILTER (Filtration and Irrigated cropping for Land Treatment and Effluent Reuse) system. The land FILTER system was tested at a medium size rural winery crushing ～20,000 tonnes of grapes. The approach consisted of a preliminary treatment through a coarse screening and settling in treatment ponds, followed by application to the land FILTER planted to pasture. The land FILTER system efficiently dealt with variable volumes and nutrient loads in the wastewater. It was operated to minimize pollutant loads in the treated water (subsurface drainage) and provide adequate leaching to manage salt in the soil profile. The land FILTER system was effective in neutralizing the pH of the wastewater and removing nutrient pollutants to meet EPA discharge limits. However, suspended solids (SS) and biological oxygen demand (BOD) levels in the subsurface drainage waters slightly exceeded EPA limits for discharge. The high organic content in the wastewater initially caused some soil blockage and impeded drainage in the land FILTER site. This was addressed by reducing the hydraulic loading rate to allow increased soil drying between wastewater irrigations. The analysis of soil characteristics after the application of wastewater found that there was some potassium accumulation in the profile but sodium and nutrients decreased after wastewater application. Thus, the wastewater application and provision of subsurface drainage ensured adequate leaching, and so was adequate to avoid the risk of soil salinisation.     

Prioritisation of farm scale remediation efforts for reducing losses of nutrients and faecal indicator organisms to waterways: a case study of New Zealand dairy farming

The international competitiveness of the New Zealand (NZ) dairy industry is built on low cost clover-based systems and a favourable temperate climate that enables cows to graze pastures mostly all year round. Whilst this grazed pasture farming system is very efficient at producing milk, it has also been identified as a significant source of nutrients (N and P) and faecal bacteria which have contributed to water quality degradation in some rivers and lakes. In response to these concerns, a tool-box of mitigation measures that farmers can apply on farm to reduce environmental emissions has been developed. Here we report the potential reduction in nutrient losses and costs to farm businesses arising from the implementation of individual best management practices (BMPs) within this tool-box. Modelling analysis was carried out for a range of BMPs targeting pollutant source reduction on case-study dairy farms, located in four contrasting catchments. Due to the contrasting physical resources and management systems present in the four dairy catchments evaluated, the effectiveness and costs of BMPs varied. Farm managements that optimised soil Olsen P levels or used nitrification inhibitors were observed to result in win-win outcomes whereby nutrient losses were consistently reduced and farm profitability was increased in three of the four case study farming systems. Other BMPs generally reduced nutrient and faecal bacteria losses but at a small cost to the farm business. Our analysis indicates that there are a range of technological measures that can deliver substantial reductions in nutrient losses to waterways from dairy farms, whilst not increasing or even reducing other environmental impacts (e.g. greenhouse gas emissions and energy use). Their implementation will first require clearly defined environmental goals for the catchment/water body that is to be protected. Secondly, given that the major sources of water pollutants often differed between catchments, it is important that BMPs are matched to the physical resources and management systems of the existing farm businesses.     

Anaerobic treatment of sulfate-rich wastewater in an anaerobic sequential batch reactor (AnSBR) using butanol as the carbon source

Biological sulfate reduction was studied in a laboratory-scale anaerobic sequential batch reactor (14 L) containing mineral coal for biomass attachment. The reactor was fed industrial wastewater with increasingly high sulfate concentrations to establish its application limits. Special attention was paid to the use of butanol in the sulfate reduction that originated from melamine resin production. This product was used as the main organic amendment to support the biological process. The reactor was operated for 65 cycles (48 h each) at sulfate loading rates ranging from 2.2 to 23.8 g SO(4)(2-)/cycle, which corresponds to sulfate concentrations of 0.25, 0.5, 1.0, 2.0 and 3.0 g SO(4)(2-) L(-1). The sulfate removal efficiency reached 99% at concentrations of 0.25, 0.5 and 1.0 g SO(4)(2-) L(-1). At higher sulfate concentrations (2.0 and 3.0 g SO(4)(2-) L(-1)), the sulfate conversion remained in the range of 71-95%. The results demonstrate the potential applicability of butanol as the carbon source for the biological treatment of sulfate in an anaerobic batch reactor.     

Sequencing batch reactor biofilm system for treatment of milk industry wastewater

A sequencing batch reactor biofilm (MSBR) system was modified from the conventional sequencing batch reactor (SBR) system by installing 2.7 m2 surface area of plastic media on the bottom of the reactor to increase the system efficiency and bio-sludge quality by increasing the bio-sludge in the system. The COD, BOD5, total kjeldahl nitrogen (TKN) and oil & grease removal efficiencies of the MSBR system, under a high organic loading of 1340 g BOD5/m3 d, were 89.3+/-0.1, 83.0+/-0.2, 59.4+/-0.8, and 82.4+/-0.4%, respectively, while they were only 87.0+/-0.2, 79.9+/-0.3, 48.7+/-1.7 and 79.3+/-10%, respectively, in the conventional SBR system. The amount of excess bio-sludge in the MSBR system was about 3 times lower than that in the conventional SBR system. The sludge volume index (SVI) of the MSBR system was lower than 100 ml/g under an organic loading of up to 1340 g BOD5/m3 d. However, the MSBR under an organic loading of 680 g BOD5/m3 d gave the highest COD, BOD5, TKN and oil & grease removal efficiencies of 97.9+/-0.0, 97.9+/-0.1, 79.3+/-1.0 and 94.8+/-0.5%, respectively, without any excess bio-sludge waste. The SVI of suspended bio-sludge in the MSBR system was only 44+/-3.4 ml/g under an organic loading of 680 g BOD5/m3 d.     

Fate of phosphorus in dairy wastewater and poultry litter applied on grassland

Large and repeated manure applications can exceed the P sorption capacity of soil and increase P leaching and losses through subsurface drainage. The objective of this study was to evaluate the fate of P applied with increasing N rates in dairy wastewater or poultry litter on grassland during a 4-yr period. In addition to P recovery in forage, soil-test phosphorus (STP) was monitored at depths to 180 cm in a Darco loamy sand (loamy, siliceous, semiactive, thermic Grossarenic Paleudults) twice annually. A split-plot arrangement of a randomized complete block design comprised four annual N rates (0, 250, 500, and 1000 kg ha(-1)) for each nutrient source on coastal bermudagrass [Cynodon dactylon (L.) Pers.] over-seeded with ryegrass (Lolium multiflorum L. cv. TAM90). Increasing annual rates of N and P in wastewater and poultry litter increased P removal in forage (P = 0.001). At the highest N rate of each nutrient source, less than 13% of applied P was recovered in forage. The highest N rates delivered 8 times more P in wastewater or 15 times more P in poultry litter than was removed in forage harvests during an average year. Compared with controls, annual P rates up to 188 kg ha(-1) in dairy wastewater did not increase STP concentrations at depths below 30 cm. In contrast, the highest annual P rate (590 kg ha(-1)) in poultry litter increased STP above that of controls at depth intervals to 120 cm during the first year of sampling. Increases in STP at depths below 30 cm in the Darco soil were indicative of excessive P rates that could contribute to nonpoint-source pollution in outflows from subsoil through subsurface drainage.     

Characterization of municipal and dairy wastewaters with 30 quality parameters and potential wastewater treatment by biological trickling filters

This study aimed to characterize raw municipal and dairy wastewaters. The quality of the collected wastewaters was determined by measuring 30 quality parameters, such as phenols, oxidation-reduction potential, oil and grease, total organic carbon (TOC), manganese, total viable count of bacteria (TVC), salinity, and biodegradability. Results were compared with wastewater disposal standards. This study also aimed to describe the potential application and performance of biological trickling filters (BTFs) in municipal and dairy wastewater treatment. Detailed reviews of trickling filter models were explained. Results revealed that two wastewater samples exceeded standard limits. The raw municipal and dairy wastewaters need treatment prior to disposal to the natural environment. Additionally, BTFs are efficient municipal and dairy wastewater treatments.     

Environmental and economic feasibility study of a total wastewater treatment network system

The synthesis of distributed wastewater treatment plants (WTPs) has been studied to reduce capital and operating costs associated with wastewater treatment. In this study, the environmental and economic feasibility of a total wastewater treatment network system (TWTNS) including distributed and terminal WTPs was estimated using life cycle assessment (LCA) and life cycle costing (LCC) methods. Wastewater sources and existing distributed and terminal WTPs in an iron and steel plant were networked. The TWTNS was generated from the optimal solution to a mathematical optimization model and compared to a conventional wastewater treatment system (CWTS). The environmental effect scores of the TWTNS were from 29.6% to 68.3% higher than those of the CWTS because of higher electricity consumption required to pump wastewater to the networked WTPs. However, the life cycle cost of the TWTNS was lower than that of the CWTS by 10.1% because of the decrease of the labor cost resulting from the closing of three distributed WTPs. Overall, the TWTNS was no more eco-efficient than the CWTS because the increase of environmental burdens outweighed the decrease of economic costs.     

O2-Fenton试剂处理对氨基苯磺酸废水的探讨

利用由O2和Fenton试剂组成的类Fenton系统处理对氨基苯磺酸废水,取得了很好的降解效果.当FeSO4(10g/L)投加量为1.2mL、H2O2(3%)投加量为3mL时,COD去除率可达到70%.     

Modeling effluent distribution and nitrate transport through an on-site wastewater system

Properly functioning on-site wastewater systems (OWS) are an integral component of the wastewater system infrastructure necessary to renovate wastewater before it reaches surface or ground waters. There are a large number of factors, including soil hydraulic properties, effluent quality and dispersal, and system design, that affect OWS function. The ability to evaluate these factors using a simulation model would improve the capability to determine the impact of wastewater application on the subsurface soil environment. An existing subsurface drip irrigation system (SDIS) dosed with sequential batch reactor effluent (SBRE) was used in this study. This system has the potential to solve soil and site problems that limit OWS and to reduce the potential for environmental degradation. Soil water potentials (Psi(s)) and nitrate (NO(3)) migration were simulated at 55- and 120-cm depths within and downslope of the SDIS using a two-dimensional code in HYDRUS-3D. Results show that the average measured Psi(s) were -121 and -319 cm, whereas simulated values were -121 and -322 cm at 55- and 120-cm depths, respectively, indicating unsaturated conditions. Average measured NO(3) concentrations were 0.248 and 0.176 mmol N L(-1), whereas simulated values were 0.237 and 0.152 mmol N L(-1) at 55- and 120-cm depths, respectively. Observed unsaturated conditions decreased the potential for NO(3) to migrate in more concentrated plumes away from the SDIS. The agreement (high R(2) values approximately 0.97) between the measured and simulated Psi(s) and NO(3) concentrations indicate that HYDRUS-3D adequately simulated SBRE flow and NO(3) transport through the soil domain under a range of environmental and effluent application conditions.     

Polyvalent cation effects on myo-inositol hexakis dihydrogenphosphate enzymatic dephosphorylation in dairy wastewater

Information is needed on organic polyphosphates such as myo-inositol 1,2,3,5/4,6-hexakis dihydrogenphosphate or phytate (IP6) contribution to the sources and sinks of dissolved phosphorus (PO4-P) in the soil-manure-water system. Effects of Na+, Ca2+, Al3+, and Fe3+ and cation to IP6-P mole ratios on the enzymatic dephosphorylation of IP6 were studied to determine controlling mechanisms of dephosphorylation and persistence in manure. Phytate- and PO4-P were analyzed by high-performance liquid chromatography. Phytate dephosphorylation by Aspergillus ficuum (Reichardt) Henn. phytase EC 3.1.3.8 decreases by 50 +/- 3.6 and 40 +/- 4% at pH 4.5 and 6, respectively, as Ca2+ concentrations increase and cation to IP6-P mole ratios reach 6:6. Polyanionic IP6 has a high affinity for Al3+ and Fe3+ and reductions in dephosphorylation average 27 and 32% at a cation to IP6-P mole ratio of 1:6 for Al3+ and Fe3+, respectively, while reaching more than 99% at a mole ratio of 6:6. A phytase-hydrolyzable phosphorus (PHP) fraction is native to ruminant animal manure and is proportional to total solids (TS) concentration in 1 to 100 g L(-1) suspensions. Added phytase, in effect, increases water-extractable P content of manure and the risk of environmental P dispersion. As the bioavailability and ecological effect of IP6-P appear to be regulated not only by pH-controlled enzyme activity but also by the associated counterions, the differential protective effects of cations influence the accuracy of manure PHP fraction estimates and increase phytate resistance to enzymatic dephosphorylation that may lead to its persistence in manure.     

Determination of steroidal estrogens in flushed dairy manure wastewater by gas chromatography-mass spectrometry

There is a critical need to accurately measure the concentrations of natural steroidal estrogens in flushed dairy manure wastewater (FDMW) to assess any potential risk of waterway contamination resulting from land application. Estrogens are a concern because low concentrations (10-100 ng L-1) in water can adversely affect aquatic vertebrate species such as fish, turtles, and frogs by disrupting the normal function of their endocrine systems. The objective of this study was to develop a sample preparation method that permits the quantification of four natural steroidal estrogens (17alpha-estradiol, 17beta-estradiol, estrone, and estriol) in FDMW by gas chromatography-mass spectrometry (GC-MS). Solid-phase extraction with graphitized carbon black was used for the bulk extraction of estrogens from FDMW and additional sample purification was accomplished with C-18. The sample preparation method allowed estrogens to be detected accurately by GC-MS in FDMW. Spiked recovery experiments indicated that the method is satisfactory for measuring the estrogens of interest in FDMW with average recovery of >90%. As expected in FDMW, characterization of the estrogen profile revealed a large abundance of 17alpha-estradiol relative to 17beta-estradiol and estrone. Estriol was not detected in FDMW. The methodology developed in this research helps provide an analytical foundation for the quantification of steroidal estrogens in FDMW by GC-MS.     

Organic ligand effects on enzymatic dephosphorylation of myo-inositol hexakis dihydrogenphosphate in dairy wastewater

Animal manure contains partially digested feed fiber and grains where phosphorus (P) is bound in organic compounds that include myo-inositol 1,2,3,5/4,6-hexakis dihydrogenphosphate or phytic acid (IP6). Information is needed on the effects of other (non-IP6) organic ligands (LIGND) on the enzymatic dephosphorylation of IP6, which is a potential source of dissolved orthophosphate P (PO4-P) in the soil-manure-water system. The effects of 1,2-cyclohexane diamino-tetraacetate (CDTA), diethylenetriamine-N,N,N',N',N'-pentaacetate (DTPA), ethylenediamine-N,N,N',N'-tetraacetate (EDTA), oxalate (OXA), and phthalate (PHTH) and LIGND to IP6 molar ratio and charge concentration ratio on IP6 dephosphorylation were studied to determine controlling mechanisms of IP6 persistence in manure. Solution PO4-P concentrations were analyzed by ion chromatography as the phosphomolybdate-ascorbic acid method partly includes IP6-P. Uncomplexed IP6 dephosphorylation by Aspergillus ficuum (Reichardt) Henn. phytase EC 3.1.3.8 at pH 4.5 and 6 is unaffected by the presence of LIGNDs. As the concentrations of Ca2+, Al3+, or Fe3+ increase, dephosphorylation is reduced. Their inhibitory effect lessens in the presence of LIGNDs, in the following order: CDTA = EDTA > DTPA > OXA > or = PHTH. Whether CDTA or EDTA is the most effective LIGND depends upon the acidity of the suspension and LIGND charge concentration, reducing the inhibitory effect of polyvalent counterions to the point of promoting the hydrolysis of a manure phytase-hydrolyzable phosphorus (PHP) fraction that is otherwise unavailable. Therefore, ligand-induced changes increase the mobilization and dephosphorylation of complexed organic P, above and beyond the simple dissolution of inorganic phosphates. An analytical method for potentially bioavailable PHP in animal manure should include a LIGND as extracting reagent. Also, potential LIGNDs in an organic carbon-rich dairy wastewater may increase the release of PHP and environmental dispersion of PO4-P.