Performance And Mathematical Model Of A Pilot-scale Combined Process Of Anoxic Baffled Reactor (ABR)-CROSS Flow Aerobic Sludge Reactor(CFASR) For Printing And Dyeing Wastewater Treatment

With the rapid development of economic and enhancement of people’senvironmental awareness, our country increases the treatment degree of the printingand dyeing wastewater. As there exists difference between raw materials, productionvarieties, production technology and management level, the quality of the printingand dyeing wastewater is different from each other. As a result, the components ofwastewater discharged by the different processes are extremely complex. Becausethere are more and more organic components that are poisonous and hard to depose.Furthermore, printing and dyeing wastewater has high organisms with high COD butlower BOD, heavy color, poor biodegradability and large emissions, some of whicheven are carcinogenic, mutagenic, distortion organic matters that have increasinglythreatens and hazards to the environment especially the aquatic environment.Traditional biological treatment for printing and dyeing wastewater has a highremoval on BOD5, but inefficient for COD, especially for toxic refractory organicmatter and chroma. It is thus clear that a single approach increasingly facing achallenge to meet the requirement of the development of the printing and dyeingindustry. After analyzing the character of printing and dyeing wastewater andcomparing the different practical wastewater treatment technology route of a sewagedisposal, we bring forward the plan through which the technology route of “anaerobicbaffled reactor (ABR)–cross flow aerobic sludge reactor (CFASR)” is utilized totreat this kind of wastewater, and modeling based on the pilot test data andADM-ASM1to instruct pilot operation.The technology of route which employs a combined process ABR–CFASR totreat the printing and dyeing wastewater was put forward on account of thewastewater characteristics. Pilot-scale operation effect of ABR–CFASR system isexamined and optimal process parameters and start running program weredetermined. The ABR results show that when the influent COD fluctuates at1000mg/L, the average removal of COD, BOD, SS and chroma were42%,19.2%,48.6%and30%, respectively. After the treatment of ABR, effluent NH4+-N raises slightly,effluent TN declines slightly compared with influent TN, and TP content in waterrises, accompany with the B/C of ABR increased from0.56to0.68, this improvements of B/C is favorable for the growth of aerobic micro-organisms in thefollow-up CFASR reactor. According to the results the startup and running programof ABR are determined: the startup HRT, pH, MLSS, MLVSS, volume-load, sludgeload were controlled at60h,7,45g/L,30g/L,2.0kgCOD/(m3·d),01kgCOD/(kgMLVSS·d), respectively;when the system being steady operationthese parameters are controlled at12h,7~9,35~50g/L,20~35g/L,6.0~18.0kgCOD/(m3·d),0.2~0.5kgCOD/(kgMLVSS·d). The result of operationeffect of pilot-scale CFASR in series with ABR show:under the condition ofHRT=20h, MLSS=1500~2000mg/L, pH=7.12~8.86, DO=2.0~3.0mg/L, sludgeload=0.2~0.8kgCOD/(kgMLSS·d), the temperature is15~37℃, the effluentCOD<100mg/L, BOD<20mg/L, which is well fitted the standard of wastewaterdischarge, the result also show that CFASR has a high potential to reduce the TN、TP、SS and chroma, which can reach more than90%,80%,90%and80%,respectively.AS printing and dyeing wastewater has a high value of pH which up tomaximum of10,so the traditional anaerobic biological treatment reactor, such asUASB, utilized to treat printing and dying wastewater must adjust pH to theoptimum pH range which is7.5~8.0by addition sulfate to the system. The result ofthe pilot-scale demonstrate that ABR has potential to treat high influent pH, whichcan attainability at9.5, compare to the traditional anaerobic treatment process, ABRsaving a large number of pharmaceutical costs as there is no need to addition sulfateto adjust pH. In addition to, ABR occupied less land as it can steady operates at ashorter HRT (12h) compare to the traditional anaerobic treatment process (morethan20h).Using the GC-MS and LC-MS analytical tools to observe the removal oforganisms and dye molecules which attribute to the ABR. The result show that ABRreactor can well degrade the influent higher alkanes, mide acids, ketones, phenols,esters which are high in the influent, but low in the effluent. by analyzing theeffluent detect that most of macromolecular materials were transferred to smallermolecules, such as cycloalkanes, quinolines, phenols, which is beneficial to thefurther degradation in the follow-up aerobic processes. The pilot-scale experimentdetection found ABR has a high reduction of naphthol AS-E, azo-dye acid orange,direct blue, anthraquinone-acid blue, but no detection of the removal of azo sudan1. Establishing the mathematical model for the printing and dyeing wastewatertreatment based on the anaerobic digestion model No.1(ADM1) and activatedsludge model No.1(ASM1) which developed by the international water association(IWA), after being amended and improved,we establish model to provide a theoretical basis for the design, optimal operation, forecast and control the effluentwater quality of printing and dying wastewater which treated by ABR-CFASR. TheABR simulated results based on the ADM indicate that the predicted date of the firstcancellus of ABR is far from the true date, the error rate is-32.8%~30.6%, while thesimulation of the third and sixth cancellus is will fitted the real date, error rate is-20%~20%. Otherwise the model of ABR show a perfect simulation for VFA、MLVSS and pH. The CFASR simulated result which based on ASM1show that inunder the different HRT, simulated dates are well inosculation with the experimentaldates at a-14%～14%error rate,which demonstrate that the model can employed topredict the effluent system of CFASR. However the ADM-ASM1combined modelpredict the effluent COD with a-18%～19%error rate, which larger than thesimulated result of CFASR account for the deviation of parameters or the deviationas the ADM simulate the ABR effluent water quality.