Hybrid constructed wetlands for highly polluted river water treatment and comparison of surface-and subsurface-flow cells

A series of large pilot constructed wetland （CW） systems were constructed near the confluence of an urban stream to a larger fiver in Xi＇an, a northwestern megacity in China, for treating polluted stream water before it entered the receiving water body. Each CW system is a combination of surface- and subsurface-flow cells with local gravel, sand or slag as substrates and Phragmites australis and Typha orientalis as plants. During a one-year operation with an average surface loading of 0.053 m3/（m2.day）, the overall COD, BOD, NH3-N, total nitrogen （TN） and total phosphorus （TP） removals were 72.7% ~ 4.5%, 93.4% ＋ 2.1%, 54.0% ＋ 6.3%, 53.9% ~ 6.0% and 69.4% ：t： 4.6%, respectively, which brought about an effective improvement of the fiver water quality. Surface-flow cells showed better NH3-N removal than their TN removal while subsurface-flow cells showed better TN removal than their NH3-N removal. Using local slag as the substrate, the organic and phosphorus removal could be much improved. Seasonal variation was also found in the removal of all the pollutants and autumn seemed to be the best season for pollutant removal due to the moderate water temperature and well grown plants in the CWs.

Contaminant removal from low-concentration polluted river water by the bio-rack wetlands

The bio-rack is a new approach for treating low-concentration polluted river water in wetland systems.A comparative study of the efficiency of contaminant removal between four plant species in bio-rack wetlands and between a bio-rack system and control system was conducted on a small-scale （500 mm length × 400 mm width × 400 mm height） to evaluate the decontamination effects of four different wetland plants.There was generally a significant difference in the removal of total nitrogen （TN）,ammonia nitrogen （NH 3-N） and total phosphorus （TP）,but no significant difference in the removal of permanganate index （COD Mn） between the bio-rack wetland and control system.Bio-rack wetland planted with Thalia dealbata had higher nutrient removal rates than wetlands planted with other species.Plant fine-root （root diameter 3 mm） biomass rather than total plant biomass was related to nutrient removal efficiency.The study suggested that the nutrient removal rates are influenced by plant species,and high fine-root biomass is an important factor in selecting highly effective wetland plants for a bio-rack system.According to the mass balance,the TN and TP removal were in the range of 61.03-73.27 g/m^2 and 4.14-5.20 g/m^2 in four bio-rack wetlands during the whole operational period.The N and P removal by plant uptake constituted 34.9%-43.81% of the mass N removal and 62.05%-74.81% of the mass P removal.The study showed that the nitrification/denitrification process and plant uptake process are major removal pathways for TN,while plant uptake is an effective removal pathway for TP.

Effects of Aeration on Nitrification Process in a Polluted Urban River

[Objective] The study aimed to discuss the effects of aeration on nitrification process in a polluted urban river, [Metbod] Through indoor simulation experiments, the effects of different aeration conditions （aerating water named Ew, aerating sediment named Es ） on nitrification process in a polluted urban river were studied.[ Result]The nitrification of the control group named Ec proceeded slowly, while two kinds of aeration promo- ted the process of nitrification, that is, the peak values of nitrate nitrogen of Ew and Es group were respectively 5.15 and 3.83 times that of Ec group. During aeration, NO2 --N accumulation in the overlying water of Ew and Es group lasted for 10 and 14 days separately, and the maximum concentrations reached 11.41 and 7.41 mg/L respectively. Nitrification process was not consistent during the two aeration conditions, that is, the rate of nitrite oxidation in Ew group was faster than that in Es group. Denitrification process was significant after aeration, and the concentration of nitrate nitrogen in Ew and Es group was 1.26 and 2.82 mg/L respectively at the end of the experiment. [ Conclusion]The research could provide scientific references for the restoration of polluted urban rivers.

Impact of River Water Quality on Public Health in Perspective of Asian Rivers:A Case Study of Buriganga River,Bangladesh

Water pollution is one of the current global problems.So many countries are suffering from this problem specifically most South Asian and Southeast Asian countries,and Bangladesh is one of those countries that are suffering from water pollution.Furthermore,the city of Bangladesh,Dhaka is one of the most densely populated cities in the world and overpopulation is showing a negative impact on the water quality now.Most of the rivers are very polluted around Dhaka city because of anthropogenic causes.This study focused on Buriganga river pollution and its impact on public health.This study intended to find out the major cause of Buriganga river pollution and the health status of the community living beside the Buriganga river.Also the study identified all the common diseases which people are suffering from around the Buriganga river area.Then the study compared the results with other southeast Asian countries so that it can make the relationship and can make it easier to understand the current situation of water pollution on public health in East Asia and Southeast Asia regions.During the research work,it was noticed that the Buriganga river is very polluted due to human activities.The transportation system,fishing,and waste canals from industries become the primary reasons behind Buriganga’s current condition.Also irresponsibility of both the environmental department and civil society is the major factor in Buriganga river pollution.The hygienic level was also not in a good condition because so many wastes like plastic materials and other daily use materials were thrown out into the river.That’s why public health conditions around the Buriganga river become vulnerable nowadays.So policies have to be implemented from the right perspective and the institutions have to be strong enough to handle all the issues regarding the Buriganga River.

Restoration processes of pollution zones in Hanjiang River

Two pollution zones in middle and lower reaches of Hanjiang River were selected for studying restoration processes. In each zones 6 stations were set up in upper stream of sewage outfall, 50m, 100 or 150m, 250 or 525m and 1250 or 3500m apart from the outfall. Chemical monitoring and microbial community biomonitoring were carried out simultaneously. Either the chemical monitoring or the biological monitoring proved the self-purification process of water body along with the increased distance from the sewage outfall. 4 biological parameters (species number of protozoa, percentage of phytomastigophora, diversity index and heterotrophy index) and parameter Seq of the colonization process all have statistically significant correlations with chemical comprehensive pollution indexes Pa and Pb.

Two-dimensional numerical algorithm for water quality modeling in the topographically complicated river

In this paper, a two-dimensional numerical calculation algorithm for the water quality modeling in the Hengyang City section of the Xiangjiang River is researched considering the effect of the Dayuandu navigational key project. The research river is winding and has two branches resulted from an isle. The numerical calculation algorithm for the water quality modeling is set up on the basis of applying topographic map of the river course and the finite element method. The calculation result for the water quality modeling includes the concentration fields for various pollutants. The numerical calculation algorithm for the water quality modeling set up in this paper can be applied to shallow river with similar topographically complicated river course.

Evaluation of aquatic rehabilitation technologies for polluted urban rivers and the case study of the Foshan Channel

An index system for evaluation of technologies for urban river rehabilitation was proposed and discussed.The index system includes indicators of cost,resources,environmental improvement,and social effects.The calculation method for an objective value of each index based on its attributes and weights was presented.The Foshan Channel,which is a seriously polluted,black and malodorous urban river in Foshan City,China,was selected as a case study.The values of the attributes and the weights of the indices for the Foshan Channel were determined.The technologies for the rehabilitation of the Foshan Channel were evaluated based on this index system.Finally,a rehabilitation scheme for the Foshan Channel was proposed.

Spatial correlations between urbanization and river water pollution in the heavily polluted area of Taihu Lake Basin, China

Water pollution in the Taihu Lake Basin has been the focus of attention in China and abroad for a long time, due to its position in the forefront of urban development in China. Based on data gathering and processing from 84 monitoring sections in this heavily polluted area, this study first analyzes spatial patterns of urbanization and the distribution of river water pollution, and then uses the GeoDa bivariate spatial autocorrelation model to investigate the spatial correlation between urbanization and river water pollution at the scale of township units. The results show that urbanization has adverse impacts on water pollution, and the influence varies in different levels of development areas. The urban township units have the highest level of urbanization and highest pollution, but the best water quality; the suburban units have lower level of urbanization, but higher pollution and worse water quality; however the rural units have the lowest level of urbanization and lowest pollution, mainly affected by upstream pollution, but worst water quality. Lastly, urban and rural planning committees, while actively promoting the process of development in the region, should gradually resolve the issue of pollution control lagging behind urban life and urban develop- ment, giving priority to construction of centralized sewage treatment facilities and associated pipeline network coverage in the rural areas and suburban areas.

Relationship between environment policy and technical transformation:industry pollution control in Three Gorges Reservoir

Ecological objective promotes local government who is in a reservoir area adopting new environmental policies which encourage firms to save energy and reduce emissions.Based on real option theory,we characterized the arrival of new environmental policy as a Poisson jump process.Under the situation that neither the policy arrival time nor contents can be determined,with the real option theory,we focused on problems for firms to decide best investment timing and scale,provided the cumulative probability distribution function of investment timing,and gave a numerical analysis.By analyzing the relationship between policy and investment decision,we found a perverse result that the high subsidy does not always encourage investment all the time,which can be a valuable reference for government to control industry pollution and make reasonable policies.

Effect of Changing the Effluent Path of Omar-Bek Drain on the Damietta Branch Water Quality

The Omar-Bek drain, which represents the main source of water pollution along the Damietta branch of the Nile River, receives about 600,000 m3 (158,503,200 gallons) daily of untreated domestic, agricultural, and industrial wastes. The main purpose of this research consisted of investigating alternatives of managing water quality at the Damietta branch;a comparison was conducted between the current situation and two proposed scenarios. The first scenario involved changing the effluent path of the Omar-Bek drain to another drain is called “Main Western drain”. The second scenario centered around improving water quality at the Omar-Bek drain by constructing a WWTP with a design capacity of more than 150,000 m3/day (39,625,800 gallons) and by improving water quality at this drain by increasing the efficiency of WWTPs that discharged daily about 60,000 m3 (15,850,300 gallons) of partially treated wastewater to the drain. The current situation and the two proposed scenarios were simulated by using river pollutant (RP) modeling. It was concluded that the Omar-Bek drain has no significant effect on the Damietta branch water quality and that, instead of changing the path of the drain, improving the efficiency of the existing WWTPs discharging to the Omar-Bek drain and preventing the direct discharge of domestic wastewater to the drain will provide the most effective ways of increasing the water quality of the Damietta branch.

Excretion of manure-borne estrogens and androgens and their potential risk estimation in the Yangtze River Basin

The Yangtze River is the longest river in China, and the river basin spans one fifth of the area of the whole country. Based on statistical data, the excretion of manure-borne steroid hormones, including steroid estrogens（SEs） and steroid androgens（SAs）, in 10 provinces of China within the region has been estimated. The potential environmental and ecological risk of manure-borne steroid estrogens to the surface water in this region was also assessed. The manure-borne SE and SA excretions in the 10 provinces and municipalities vary in the order： Sichuan 〉 Hunan 〉 Hubei 〉 Yunnan 〉 Jiangsu 〉 Anhui 〉 Jiangxi 〉Chongqing 〉 Qinghai 〉 Shanghai. The highest increase of manure-borne SEs（1434.3 kg）and SAs（408.5 kg） was found in Hunan and Hubei provinces, respectively, and the total excretion in 2013 was 65% more than 15 years earlier in these two provinces. However, the emissions in Anhui and Shanghai decreased in this 15 year period of time. Swine urine,chicken feces, cattle urine, and laying hen feces were considered the dominant sources of manure-borne E1, βE2, αE2, and SAs, respectively. Although Jiangsu province did not have the largest excretion of manure-borne SEs, it had the highest level of predicted17β-estradiol equivalency（EEQs） value of 16.65 ng/L in surface water because of the limited surface water resources. According to the lowest observable effect level of 10 ng/L for17β-estradiol, the manure-borne SEs in Jiangsu province might potentially pose ecological risk to its wild aquatic organisms.

TARGET ANALYSIS OF SUZHOU CREEK REHABILITATION PROJECT STAGE II: BASED ON WATER QUALITY MODEL

The Suzhou Creek is a seriously polluted tid-al river in Shanghai. The SuzhouCreek Rehabilitation Project was launched in 1998, and the total investment will surpass 10 billionyuan RMB. It is important to assess the effectiveness of the project and ascertain its targets. Inthis study, by analyzing the achievements of Suzhou Creek Reha-bilitation Project (Stage Ⅰ) and itsremaining problems, the main tasks of the Project Stage Ⅱ are proposed. These works are wastewaterinterception, sediment dredging, bidirectional water diversion, and reconstruction of municipalpump stations. The water quality model established with USEPA''s WASP is employed to analyze thequantitative targets of the Project Stage Ⅱ. In the Project Stage Ⅱ, the water quality ofmainstream and tributaries will be improved continuously, the valus of COD_(Cr), BOD_5 , DO in themainstream will steadily attain Class Ⅳ according to the National Surface Water Quality Standard,and the ecological environment of Suzhou Creek with continuously recover.

Biomarker for monitoring heavy metal pollution in aquatic environment:An overview toward molecular perspectives

Water pollution is a significant problem in almost all parts of the world.The complexity of anthropogenic activities along the watershed seems to lead the river to function as a giant disposal container.The river is under threat of degradation,mainly due to heavy metal pollution from anthropogenic actions.Heavy metals become harmful if they pollute waters since they are accumulative,toxic,and carcinogenic in water bodies and biota.Various biomarkers to evaluate heavy metal contamination in several aquatic organisms have been widely reported.The use of molecular biomarkers become more popular in the last years and still lead for future prospect.Proteomics and genomics with bioinformatics approaches have been expanded with technological methods through DNA and RNA sequencing and mass spectrometry based proteomics.Therefore,this article aims to review studies using biomarker approaches in many aquatic organisms.This review is expected to reference and encourage future biomarker research,especially for monitoring heavy metal pollution in rivers.