On the treatment of cyano-bacterialbloom based on chemical algicide with mainingredient of acetic acid, theresearch was carried out in Xuanwu Lake in Nanjing in 2005 by which, after thetreatment, the total algae of theexperimental area reduced by 82.8%. Bioremediation Technologies:Indigenous or cultivated microbes andother organisms are used in bioremediation totransform the harmful and poisonouspollutants to non-toxic substances under the controllableenvironment. In order  to eliminate the gasoline pipeline leak inPennsylvaniain 1972 bioremediation process was used. It played a significantrole as the main means.

It was likely the firstlarge-scale application at thistime. It was a important step in the development of bioremediation andattractedmore and more concerning.The bioremediation could be dividedinto artificial and natural bioremediation according to the degree of humanintervention,  and the prioer could bedivided into in-situ bioremediation and ex-situbioremediation. The in-situbioremediation, on one hand, means to use bioremediation technologydirectly inpolluted rivers without any pollutant transported. Indigenousmicrobes whichsometimes combine with domesticated microbes are used by this method.

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In theEx-situ bio-remediation the polluted water was taken out from the contaminatedareas for transportation.Therefore, the bioremediation wasadvancedrapidly from 1990as engineering technology for river pollutioncontrolling,. There are many benefits for the bioremediation technology, suchas reduced cost with low environmental influence, reducingpollutantconcentration by the maximum extent,no secondary pollution orpollutant movement, available for the sites where general pollution treatmenttechnologyis hard to be applied. This bioremediation technology is the only mostpromisingremediation.Remediation by aquaticplants: Aquatic plants have a certain degree ofpurification for water.

The plants having good absorption capacity for aquaticpollutants could be implanted in the dirty and polluted water. Similarly waterpollutants were fixed by adsorption, absorption, accumulation anddegradation bythe plants for water purification.Based on the laboratory experiments,GuoChangcheng and his group verified that thepotamogeton had good cleansingresult for the polluted river water.

Tong Changhua used aquatic plants toremove eutrophication from the urban river water. The results revealed that aquaticplants had a good capacity to remove TN, TPand nitrate nitrogen. Foxtail alga andgrain leaf pondweed could efficiently remove TN (83.84% and 77.54%), TP (91.

3%)and nitrate nitrogen (95.85% and 90.65%), but had no substantialeffect oneliminating ammonia nitrogen (only 14% to 70%).Remediation method byaquatic animals:The aquatic animals were used to reducethe water of algal bloom and to modify theaquatic nutrition by changing theconfiguration and density of fish. The algal bloom formed by phytoplankton canbe removed by the use of silver carp, common carp and other filter-feedingfish. MicrobialRemediation Method:Bio-filmformation:The bio-film method uses bio-membranewhich is fixed to the natural river bed and micro-carrier tomove thecontaminantsof  the river by adsorption,degradation and filtration through theartificial aeration or dissolvedoxygen.The bio-film study showed that its structure can be affected by watercondition and by the structure of substrate.

The bio-film formation  method for purification of  river  in Japan,  South Korea and other countries were gravelcontact oxidation method, artificial packing contact oxidation method, thinlayer flow method and underground stream purification method. Japan used thegravel contact oxidation method for water purification of river and the removalrates for BOD and SS were significant. In china by using non-woven fabric aspacking substrate then removal efficiency of SS  reached to 97 %, for BOD 88%.Park, Y. K.used biological activated carbon to sieve and clean the pollutedKumbo River water, and theremoval rate for ammonia was 90% and  the removal rateof TOC was also significant. Lei Jin Yong used the composite pcking of pebblesand zeolite for bio-film formation for the degradation of organic matter,ammonia and nitrogen. MicroorganismDosing method: This technology utilizes the specificand effective microorganisms for the absorption, purification and transformationof the contaminants in the river water.

The production of highlyactive compoundbacteria was the significant step to determine the influence of microorganismdosing.At that time, it was studied and utilized for the purification of sewage,industrial wastewater and for the water of algal bloom. FLO-1200achieved remarkable results in the river pollutioncontrol under the conditionsof river aeration.Conclusion:Theresearch in foreign countries started in Japan, U.

S and some other Europeancountries for river control in the 50s of 20th century and afterthat river pollution control became an international problem. China startedresearch work for river control in 1990s and has done much remediation work.· To obtainecological development of the river ecosystem, the river should be treatedwithbio-eco remediation and with physico-chemical remediation.

· Bioremediationmaterials should be checked and the mechanism of bio-remediation should bestudied carefully before it is directly applied to the river.· The generalconditions of many technologies such as aeration, bio-film and microbialformationand dosing  for river pollution control are investigated.· The waterpollution control for Nansha River developed by using coupled model based onthe models EFDC and WASP. For scenario analysis coupled models which lead torecommendations to improve water quality in Nansha river. Estimation of amountand distribution of waste-water from domestic and industrial waste water basedon the waste water treatment plant (WWTP) scheme developed by public authority.