外文翻译---去除废水中磷的技术

1、附录2外文资料原件Technologies to Remove Phusphwus frimi WastewaterPeter F. StHHllProfessor of Emironmcnfl Science, Rnfgci*s l：nhci*sityAugust 2tJO6This brief literature rev icw examines trealincut techiioloeics available for wastewater trenttneid planh to rem me phasph(mis. Although it is not mean( In be cx

2、hausiivc or coinplcte, it docs iiLchidc some oi tlie newest available reporii on P removal.rrentment teclmolo ics pjvscntk a aikible t<>r phnsiphonic rctno al mclude:Physical:tilli atiou for pai ticulate phosphorus mcirihraiic tcchnclngicsCh cniieid:precipitationother (mam Iv physicakeheniicaJ

3、 ackorption)BiologLcalassimihtionenhanced biological phosphoms removal (EBPFi)The greatest intcrcsr and most recent progress has been made in EBrR, which has the |ioltnLial to ienio e P ilown Iq ery Iuta Lex els at reJati ely lowti costs. Xlembiaiie tcchnnlngics arc nho receiving inercascd attention

4、, altho'Lih their use for P remal h酬 been iiioj e limited to date. The quebtioLi of sdudg亡 handling 日nd ueatuient of P m side stTsjainis also hem itddr#汕uLA. Pfiysicjl TreniHiciitL Filtration (br particulate PAssuming that 2-3% of organic solids is P, then an effluent total susp ended solids (TS

5、S) of 20 mg/L represenU 0.4-0.6 mg/L of cllluetU P (Strom, 2006b), In plantB with EBPR the P content is even higher. Thus sand filtration or other method of TSS remo al (c.g < membrane, chemical prccipitatioii) is likely nccessajy for plants with low cfthiciit TP penintfj (Rjtiurdoji, 2006).2, Mv

6、mhrnnp technnl(ij>k'sMembrane tcclmologins hfn & been of growing iiiiercst for wastewater treatment in g eiteraL 3nd most recently, tor P removed in parkuhj A recent 3 day natio(ial VraUr Em ironmcnt Rcsciuch Fcutidation (WERF) workshop on uchic inu low eflliient nutrient levels devoted a

7、n entire session 4 papers) to tliis topic (WERF 2006). In addition toremoving the P in the TSS, membranes also can remove dissolved P Membrane biorcactors (MBRs, which incorporate membrane technology in a suspended growth secondary treatment process), tertiaiy membiane filtration (after secondaiy tr

8、eatment), and eise osmosis (RO) systems lia e all been used ui full-scale plants with good results. Reardon (2006) reported on several plants aehiex ing <0.1 mg/L TP in their effluent, and suggested tlie current reliable limits of technology are 0.04 mg/L tor MBRs and tertiary membrane filtration

9、, and 0.008 mg/L for RO.B. Chemical Treatment1. Preci pi ttiunChemical precipitation has long been used for P removal. The chemicals most ollen employed aie compounds ol calciuin. aluininuin, and iron ( rdiobanoglous et al.n 2003) Chemical addition points include prior to primary settling, during se

10、condary treatment, or as part of a tertiary treatinenl process (Neetliling and Gm 2006). Song el al. (2002). using thermodynamics, modeled the effects of P and Ca concentration, pH. temperature, and ionic strength on theoretical rcmovaL Researchers (e.g., Hcnnanowicz, 2006) generally agree, however,

11、 that the process i« more complex than predicted by laboiatoiy pure chemical expenments, and tliat formation of and sorption to carbonates or hydioxides are important factors In fact, full-scale systems may perlbnn better tlian the 0.05 mg/L limit predicted (Neetlilmg and Gu. 2006). Takacs (200

12、6) suggests tlie limit is probably 0.005-0.04 mg/L.A major conccm with chemical precipitation for P removal continues to be the additional sludge that is produced. This can be dramatic, especially if tlie method selected is lime application during primary treatment (Tchobanoglous et al., 2003) l：se

13、of alum after secondary treatment can he predicted to produce much less sludge, but tlie increase could still be problematic (Strom, 2006a).2 OfheiThe precipitation methods described above rely in part on sorption to achieve the low concentrations obsen ed Moller (2006) reported on an iron reactive

14、filtration system achieving <0.01 mg/L TP at a 1.2 MGD (average flow) plant. Woodard (2006) described a magnetically enhanced coagulation process that may achieve <0.03 mg/L TP based on long term pilot tests.Gas concrete (produced from mixtures of silica, sand, cement, lime, water, and aluminu

15、m cake) waste was used to remove phosphate from pure aqueous solutions (Oguz et al., 2003). High phosphate removal (> 95% in 10 min, batch system) was obtained from a 33 mg?L P solution, but direct applicability to waste water treatment (lower concentrations, possible interferences) was not im es

16、tigated The gas concrete's removal efficiency can be regenerated at low pH, with the resulting concentrated phosphate solution potentially a source of recycled phosphate Similarly, iron oxide tailings were found to be cfifcctix c for phosphonis removal from botli pure solutions and liquid hog ma

17、nure (Zeng ct al., 2004).C. Biological Trertfinenf1. AssimilationPhosphorus remo al from astexvater has long been achie ed tlirough biological assimilation 一 incorporation of the P as an essential element in biomass, particularly through growth of photosynthetic organisms (plants, algae, and some ba

18、cteria, such as cyanobacteria) Traditionally, this was achieved tlirough treatment ponds containing planktonic or attached algae, rooted plants, or even floating plants (e.g., water hyacintlis, duckweed). This continues to be an area of reseaich (e.g., Awnali et al. 2004), although less so in the no

19、rtheastern USA Land application of effluent during tlie growing season has also been used, and constnicted wetlands are now an established practice as well. In all of these cases, however, it is necessary to retn ove the net biomass growth in order to prevent even hi al decay of the biomass and rc-r

20、clcasc of the P (Strom, 2006a). Interestingly; assimilation was not discussed at the WER1; (2006) workshop2. EBPRAs indicated in the introduction, tlie greatest recent and present interest has been in enhanccd biological phosphorus removal This is because of its potential to achieve low or oven very

21、 low (<0mg/L) effluent P levels at modest cost and with minimal additional sludge production. Removal of traditional carbonaceous contaminants (BOD), nitiogen, and phosphorus can all be achie cd ui a single system, although it can be challenging to achieve ery low concentrations of botli total N

22、and P in such systems.A detailed re iev ol EBPR microbiology is given m Xlino et al. (1998) Nhilkernns et al. (2003) also have reviewed the process To sunmiarize (Strom, 2006a and 2006b)： phosphate accunuilating organisms (PAOs) store polyphosphate as an energy reserve in intracellular granules. Und

23、er anaerobic conditions, in the presence of fermentation products, PAOs release orthophosphate, uliliznig die energy to accumulale simple organics and store them as polyhydroxvalkaiioates (PHAs) such as poly-卩 hydioxy butyrate (PI 113). Under aerobic conditions, tlie PAOs then grow on tlie stored or

24、ganic material, using some of the energy to take up orthophosphate and store it as polyphosphate Thus P?Os, although strictly aerobic, arc selected for by having an upfront anaerobic zone in an activated sludge type of biological treatment process. The PAOs are able to compete with other aerobes und

25、er these conditions because of tlieir ability to sequester a fraction ol tlie a ailable organic material under tlie initial anaerobic conditions, while ont-competing the anaerobes because of the much higher energy yield from aerobic vs. fermentative metabolism.The phosphate in EBPR is removed in the

26、 waste activated sludge, which might have 5®oor more P (dry weight) as opposed to only 2-3% in non-EBPR sludges. EBPR has been demonstrated in several systems (Tchobanoglous et al.9 2003), such as tlie various Bardenplio processes (also reinove N), tlie A/O and AZA/O or A2O (removes N) processe

27、s, sequencing batch reactors (SB Rs), and the Pho Strip process (wliich combines EBPR witli phosphate stripping and chemical removal). Siinultaneous biological nutrient removal (SBXR) has also been observed in treatment systems, such as the Orbaloxidation ditch, not specifically designed for nutrien

28、t removal. SBNR recently has been exauuned iii some detail (Littleton et al., 2000, 2001, 2002a, 2002b, 2003a, 2003b, accepted I, accepted II; Strom et al., 2004)James Barnard (2006), developer of tlie Bardenpho process, recently moderated a session on tlie capabilities and constraints of EBP1< a

29、nd discussed tlie requirements for achieving effluent P concentrations <0.1 mg/L. He emphasized the need for production oi olatile fatty acids by iemientation in order to assure their availability ibr the PAOs Some of tlie factors contributing to tlie difficulty of achieving very low lc cls of bo

30、tli N and? sunultaiieously were pointed out, including secondary release oi P in anoxic zones The need to select for PAOs ox er the competing glycogen accumulating organisms (GAOs) was also discussed, with the following factors favoring GAOs: high sludge age, high temperauire, longer un-aerated dete

31、ntion times, stronger wastes witli low organic N, polysaccharides fed to the anaerobic zone, and low pH.Xeetliling et al. (2005) examined die factors dial uilluence the reliability of EBPR in hill-scale plants They concluded tliat P concenti-ations <0.1 nig'L can be achieved for extended peri

32、ods (more than a month), 0.03 mgL for a week, and even below 0.02 mg/L lor se eial sequential days Excursions above thesD levels are common/' A sufficient BOD/P ratio (>25:1) is one requirement for reliable high removal efficiencies. This might be achiex ed by BOD augmentation through fennent

33、alion or addition of a fermentable substi ate Conti ol of recycle sti eams is also necessaiy, so tliat tliey do not bring too much P back to the EBPR process. They also concluded that while GAOs can be problematic, tlieir presence does not preclude good P remox al.Randall (2006) also discussed the u

34、se of carbon augmentation in EBPR. Short chain volatile fatty acids (VFAs), particularly acetic and propionic acids, are most des li able Some caibon sources, such as some sugars and alcohols, may lead to production of GAOs： bulking, or excessive exocclhilar polymer production. VFAs may be generated

35、 in the sewer system, aiise liom industnal discharges, be adekd directly, or be generated on-site. For many plants, on-sitc generation in the anaerobic zone may be sufficient Alternatively, fermentation of tlie priinaiy sludge, pmnaiy eflluent or some of the activated sludge might be practiced. In t

36、he PhoStrip process, fennentation also occurs in tlie shipping tankCold weather can provide a challenge for many biological treatment processes 1 Iowexer, tlie Kalispell, Montana waste water treatment plant has maintained a long-tenn average effluent phosphorus concentration of 0.11 mg/L (Emrick, 20

37、06) with a Baidenpho process modification (UCT). This area lias only 91 frost-free days per year, with average winter high and low tern|>eratxires of 30 and 15°F, respectivelyAkm and Ugurlu (2003) examined nutiient removal hi a laboratoiy sequencing batch reactor (SBR) system with a new oper

38、ational mode: sinniltancous feeding and decanting fhe synthetic wastewater contained glucose and acetate as carbon sources, and 20 mg/L P (COD/P ratio 一 20). Filtered cfTliicnt P concentrations below 1 mg/L (and as low as 0.1 mg/L) were achiex ed under some operational conditionsCom erting a non-P r

39、emox ing activated sludge to EBPR by acclimatization to alternating anaerobic and aerobic conditions lakes 40-100 days, but many EBPR systems experience start-up failure or breakdown (Daberl et al., 2005). Bioaugmentation (inoculating witli prex iously adapt已d microorganisms) was found to speed up t

40、he process for a laboratory SBR by about 15 days compared to a non-augmented control.Optimization of dissolved oxygen, sludge age, and nitrateN concentration for elTicient phosphorus removal were tested at an A2O wastewater tiatment plant ui Guilin, China, (Li et al., 2005). Results showed tliat DO

41、must be controlled in the anaerobic phase, nitrate-nitiogen concentration must be deceased in the anaerobic section, and a sludge age of 8-10 clays was preferable to 15 clays.Kuba ct al. (1997) examined the role of denitrifying phosphorus removing bacteria (DPB) in wastewater treatment plants using

42、batch tests with activated sludge from two plants in the Netherlands DPBs appeared to be of little importance in one plant, but contributed substantially to P removal in the otherD. Sludges and Side StreamsI here is some concern about the effects of solids management processes and return side stieam

43、s on the ability to remove P to low le els Processes that destroy organic material (such as digestion) have tlie potential to release the paiticulate organicP present as soluble organic or uioiganic P In particular, anaerobic conditions are likely to release soluble P from EBPR sludges and iron prec

44、ipitates (fenous phosphate is much more soluble than ferric phosphate). Any released P may then be returned to tlie main wastewater treatment process in high concentrations through recycle side streams, thus requiring removal a second time. Non-continuous processes may also lead to variable loadings

45、 from side streams. A number of these issues were discussed by Narayanan (2006).In some cases, these problems, particularly witli anaerobic digestion, have not been as sex ere as originally anticipated, or could be controlled (deBarbadillo, 2006). This appear in pail to be related to the formation o

46、f the mineral struvite, blgNH/PO Sbuvite has long been known for its potential to cause clogging in anaerobic digesters (Vaccari ct al., 2006), where ammonium and phosphate arc released as the organic matter is degraded However, it appears that fonnation of this mineral in digesters at EBPR plants m

47、ay lead to its precipitation as small granules tliat remain witli tlie sludg已弓 ratlier than the release of soluble P to the supernatant where it ould be recycled This is appai ently enhanced by tlie liberation of Mg* by PAOs as a ma jor associated cation during phosphate release (I.iao et al., 20()3

48、).Aiiotlier approach is to remote tlie P from the recycle streain. Button et al. (2005) demonstrated treatment of anaerobic digester supernatant in pilot scale using a fluidized bed reactor. Phosphate was recovered in the form of struvite through the addition of magnesiuin chlorid已 and pH adjustment

49、 Liao et al. (2003) looked at release of P directly from EBPR sludge by several methods for possible P recovery Takiguchi etal. (2004) tested thennal (70 C) tieatineat followed by precipitation witli Ca in a lab- scalc.A ckiiowkdgmentsI won Id like to thank Erin Murphy and Amy Royajian for their con

50、tributions to lliis re wwLiterature CitedAkni, BS and A. Ugurlu. 2003 Biological removal of carbon, nitrogen and phosphorus in a secpiencmg batch reactor Journal of Environmental Science and Health. 38. 1479 1489Awuali. E. Nl. Oppong-Peprah. II.J. Lubberdiiig. and 1I.J. Gi|zen. 200丄 Compaiative perf

51、orm ancc studies of water lettuce, duckweed, and algal-based stabilization ponds using low strength sewage Journal of Toxicology & Environmental Healthy 0-7, 1727- 1739Barnard. J. 2006 Requirements for achieving ellluenl phosphorus of less tlian 0.1 mg/L. Session Pl in WTRF, 2006.Britton, A., F.

52、A. Koch, D.S. Mavinic, A. Adnan, W.K. Oldham, and B. Udala 2005. Pilot-scale struvite recovery from anaerobic digester supematant at an enhanced biological phosphorus removal wastewater tri atinent plant. Journal of Environmental Engineering & Science、4, 265-277.Dabcrt. P., J.P. Del genes, and J

53、 J Godon. 2005. Monitoring the impact of bioaugmentation on tlie start up of biological phosphorus removal in a laboratory scale activated sludge ecosystem Applied 'lie ybiology & Biotechnology 66, 575-588 deBaibadillo, C 2006. Biological phosphorus removal at tlie McDowell Creek WWTP. Sessi

54、on Pl in WERF, 2006.Emrick, J. 2006. Cold weather BNR limits. Session Pl in WERF, 2006.Hennanowicz, S 2006 Chemical fundamentals of phosphonis precipitation. Session P2 in WERF, 2006.Kuba, T., MC.M. van LoosdrechU F.A. Brandse, and J.J. Heijnen. 1997. Occurrence of denitrifying phosphorus removing b

55、acteria in modified UCT-type wastewater treatment plants. Water Research、31,777-786.Li, J., II. Ren, X. Wang, Q. Liu, and Q Xie 2005. Technique for biological phosphonis removal. Pollution Engineering 37, 14-17Liao, P.H., L). Iaviiuc, and F A. Koch 2003 Release of phosphonis from biological niitiien

56、t remo al sludges: A study of sludge preti eatinent methods to optimize phosphonis release for subsequent recovery purposes Journal of Environmental Engineering & Science 2. 369-381.Littleton. H.X. G.T. Daigger. P.F. Strom, & R.M. Cowan. 2000. E aluation of autotrophic denitrification and he

57、terotrophic nitrification in simultaneous biologicalniitnent removal systems Proceedings, WEB FEC 2000, 73rd Airnual Conlei-ence, Water Em ironment Federation, :naheim, CA, Session 19, 21 pp. CD-ROM.Littleton, H.X., G T. Daigger, & PF. Strom 2001. Application of computational fluid dynamics to c

58、losed loop biorcactors analysis of tn acre environment variations in simultaneous biological nutrient removal systems. Proceedings. WEE1EC 2001. 74tli Annual Coiilerence, Water Em lromneiit Fedeiation, Atlanta, GA |CD-ROM |.Littleton, H.X., G T Daigger, P.F. Strom. & R.M. Cowan. 2002a. Evaluatio

59、n of autotrophic denitrification, heterotrophic nitrification, and PAOs in full scale simultaneous biological nutrient removal systems. Water Science & Technology 46(1- 2):305-312.Littleton, H.X., GT. Daigger, P.F. Strom & R. Jin. 2002b. Simulation of BIO P removal iii CFD environment: Analvsis of macroen ironmeiil variations in simultaneous biological nutrient removal systems. Proceedings, WEFTEC 2002, 75th Annual Conference, Water Ein ironmeiit l eder