Water Purification Function Research Articles

Simulation and evaluation of the water purification function of Zhalong Wetland based on a combined water quantity-quality model

The water purification function of natural wetland systems is widely recognized, but rarely studied or scientifically evaluated. Extensive studies have been carried out by various international wetland research communities to quantify the water quality improvement ability of the natural wetlands, in order to maintain such ability and wetland ecological health. This study aims to evaluate the purification function of Zhalong Wetland in China for removing total nitrogen (TN) and phosphorus (TP), based on ex-situ experiments and the development of a combined water quantity-quality model. Experiments and model predictions were carried out with different input TP and TN concentrations. Statistical analyses demonstrated that the relative errors between model simulations and experimental observations for TN and TP were 8.6% and 12.4%, respectively. With water retention time being maintained at 90 d, the removal rate of these pollutants could not reach the required Grade V standards, if the inflow TN concentration was over 42 mg L−1, or the input TP concentration was over 14 mg L−1. The simulation results also demonstrated that, even with Grade V quality standard compliance, when the water inflow from surrounding industries and agriculture lands into Zhalong Wetland reaches 0.3×108 m3 a−1, the maximum TN and TP loads that the reserve can cope with are 1.26×103 t a−1 and 0.42×103 t a−1, respectively. Overall, this study has produced a significant amount of information that can be used for the protection of water quality and ecological health of Zhalong Wetland.

Study on a Kind of Eco-concrete Retaining Wall's Block with Water Purification Function

Considering the environmental protection requirements for retaining wall and slope protection in Civil engineering and construction of water conservancy, a new type of retaining wall materials and structures with functions of slop reinforcement, slope greening and water purification was studied. In this paper, it designed a kind of Eco-concrete retaining wall's block which has functions of slope vegetation planting and water purification, and studied functions of water purification of this kind of Eco-concrete retaining wall's block through the water quality purification experiment. It shows that, the maximal disposable removal rates of CoDcr, TN and TP are respectively 87%, 70% and 90%, which means that functions of water purification of this kind of Eco-concrete retaining wall's block are very good.

Spatial Characteristics of Water Quality of Wetland in Northeast China– the Case of Zhalong Wetland

Abstract Water quality of wetland has multi spatial distribution characteristics which are the integral impact of pollutant distribution, hydrodynamics field and topography. This article analyzed the hydrochemical field characteristics to indentify the water purification function of Zhalong Wetland. The result indicated that the water of Zhalong Wetland was purified remarkably in the wetland ecosystem.

Nutrient Transport and Change Driven by Sub-surface Flow in Alternate Bar Reach

Abstract The landscape of a river sandbar is composed of several elements, including vegetation, bare areas, side-pools and so on. For sandy river management, it is necessary to determine the contributing factors for the ecosystem functions of alternate bar segments. In recent years, it has been reported that sandbars have a water purification function involving denitrification driven by sub-surface flow, but the details are still unknown. The objective of this study was to develop a model that could be used to examine how the nitrogen is trapped and retained by several elements of a sandbar in an alternate bar reach. We also developed a framework to analyze the temporal change in the denitrification by using a numerical simulation, aerial photos, and a water quality information system. The numerical simulation was performed under the discharge and morphological conditions of the Yahagi River in the Chubu region of Japan. The main results of this study are that the temporal change in the denitrification ecosystem function in a sandbar reach can be quantified using the proposed model and the denitrification activity has increased over the past 40 years. In addition, it was clearly shown that differences in the vegetation distribution and sandbar shape affect the nitrogen dynamics. Thus, the numerical simulation has made it possible to determine the most effective vegetation patterns to maximize the ecosystem function in a sandbar.

Study on Different Water Purification Function of Water Conservation Forest in Kanto Mountains

Study on Different Water Purification Function of Water Conservation Forest in Kanto Mountains

Assessing the cost-effectiveness of the water purification function of wetlands for environmental planning

A reduction of nutrient input into freshwater and marine water bodies is a prerequisite for the restoration of healthy aquatic ecosystems and for the achievement of the ambitious goals of the European Water Framework Directive and the HELCOM and OSPAR convention. In Northern Germany, phosphorus inputs from point sources were reduced by nearly two-thirds compared to the phosphorus load in the period 1980–1985. This success was made possible by the investment of 2.1 billion € since 1985 in the development and enhancement of waste water treatment plants. However, these investments had only little effect on nitrogen inputs, which enter water bodies mainly from non-point sources. In 2002, the federal state Schleswig-Holstein implemented a peatland rehabilitation program aiming to restore the water purification function of this wetland type. The rationale of this plan is based on an economical analysis of the effects of the investments in the waste water action plan. A reduction of the P load by 1 kg has mean costs between 70 and 100 €. Based on model calculation, restoring wetlands for water quality purification will cost between 1 and 50 € per retained kg of nitrogen when considering a 10-year time span. Compared to the waste water action plan, wetland restoration is also a cost-efficient strategy for nutrient load reduction. For 10% of the investments of the waste water action plan, the nitrogen load from Schleswig-Holstein can be reduced by 10%; this will require rewetting of 20,000 ha of wetlands. The implementation of this strategy as well as the application of the concept of ecosystem services in environmental management is currently limited by a lack of political support and funding for such projects from higher political bodies such as the European Union.

Evaluation of biological water purification functions of inland lakes using an aquatic ecosystem model

An effective measure to cope with eutrophication of lakes is to remove nutrients that can cause algal blooming by taking advantage of natural water purification processes. Here the term “ purification” is defined, in a wide sense, as the potential role of a water body to contribute to the reduction of pollutants and thus controlling eutrophication. Also regarded as a kind of ecological regulating services, biological purification involves various processes concerning seasonal nutrient fixation, such as uptake by aquatic macrophytes, biofouling onto foliage substrates, feeding by organisms in higher trophic level, and eternal loss or removal of substance from the water. In order to evaluate the water purification ability, a numerical lake ecosystem model highlighting the role of macrophyte colonies in the shore zone was developed and applied to Lakes Suwa, Kasumi and Biwa, as well as five small lakes attached to Lake Biwa. The model includes the biological interactions between pelagic compartments (phyto- and zooplankton, detritus, dissolved organic matter, pelagic fish and nutrients) and benthic compartments (macrophytes, epiphytic algae, phytal animals, macro- and megalobenthos, and demersal fish). Under dynamic forcing of meteorological and hydrological parameters, the model was run over a year to evaluate the annual nutrient cycles and purification functions. The reproducibility of the model was validated for each water body by comparison with the field data from the water quality monitoring campaign. Numerical results revealed that the water purification ability, from viewpoints of both stock and flux, generally tends to be higher in the shore region than in the offshore region owing to a wide variety of aquatic biota. Moreover, it increases almost in proportion to the density of vegetation in the shore region. Nutrient fluxes representing the purification processes turned out to be closely connected with the surface area or equivalently with the retention time of the water bodies, suggesting that biological purification does not become dominant against physical turnover until the surface area reaches around 10 3 ha or the retention time exceeds the order of 10 2 days.

Adaptive Management and Evaluation of Water Purification Function on the Constructed Tidal Flat in Kuwait Bay

A lagoon type tidal flat was constructed at the coast of Kuwait Bay to verify its water purification function, since tidal flats in Kuwait Bay seem to play important role on water quality improvement in the bay. Although recruitment of tidal flat organisms was expected to bring water purification function to the constructed tidal flat, unforeseen sludge accumulation degraded their habitat condition. To solve the issue, original design of the tidal flatelevation was modified based on the causal analysis. As a consequence, habitat condition was improved and the effectivenessof adaptive management process was proved. The observed water purification capacity of the constructed tidal flat wasmaximally corresponded to a waste water facility with a capacity of about 2, 000 people, although continuous monitoring survey was required.

Evaluation of Water-purification Function of Drainage Canal System in Betsukai Area

Evaluation of Water-purification Function of Drainage Canal System in Betsukai Area

Non-Farmers' Willingness of Participation in the Maintenance and Management of Irrigation Canals

Nowadays, the irrigation is one of the most important regional resources, because it supplies “regional water”. However, it is very difficult to maintain irrigation canals, because a lot of farmers who are in charge of maintenance are either with side jobs or aged. The irrigation is utilized for living water by all the residents in the area. Therefore, all the residents (farmers and non-farmers alike) are responsible for taking part in the maintenance and management of the irrigation, especially in suburban areas. In this paper, we analyze the non-farmers' willingness of participation in the maintenance and management. Firstly, we analyze the difference in the non-farmers' recognition on the attractions concerning irrigation between urban area and rural area. The difference in non-farmers' willingness of participation in the maintenance and management of the irrigation between those two areas are analysed as well. Secondly, the factors which affect the non-farmers' willingness of the participation in the maintenance and management of the irrigation are analysed. The study area of analyses is the Central Area in Toyama Prefecture. Main methods of analyses are Chi-Square Test and Logit model analysis. The followings are most important findings through above-mentioned analyses. 1) The factors which affect non-farmers' willingness of participation in the maintenance and management of irrigation in urban area are whether they have children or not, whether the purpose of utilization or not, their evaluation on the ecological functions of irrigation , and whether they are willing to participate in the attractions concerning irrigation. 2) On the other hand, the factors affecting non-farmers' willingness in rural area are their sex, whether they have children or not, the frequency of their use of irrigation, the distance from their house to the irrigation canals, their evaluation on the water purification functions of irrigation, and whether they are willing to participate in the attractions concerning irrigation.

Biological Production and Water Purification Functions of Mega-infaunal Community at an Artificial Tidal Flat

Biological Production and Water Purification Functions of Mega-infaunal Community at an Artificial Tidal Flat

浚渫砂を用いて造成した干潟・浅場による沿岸海域環境への効果とその課題について

The Ministry of Land, Infrastructure and Transport and Aichi Prefecture are jointly involved in various environmental rehabilitation and creation projects inside Mikawa Bay. New tidal flats and shallow waters have been created and capping has been conducted through the utilization of high quality dredged sand arose from the development of Nakayama waterway. Results from the monitoring survey in 7 years showed improvement in sediment quality and disappearance of oxygen depleted water column in the tidal flat. Also diversity of bivalves and other benthic organisms have increased in the tidal flat area, suggesting an improvement of the habitat environment. In addition, Bivalves play an important role in water purification function. When the increased purified nitrogen in water, owing to recovery of bivalves in the created tidal flat, is multiplied by the total project area (620ha), the amount of purified nitrogen becomes 815kgN/day. It is equal to approximately 2% of the whole nitrogen load to Mikawa Bay.

벼농사에서 질소유출이 수질에 미치는 영향평가

It is important to understand and evaluate the environmental impacts of rice cultivation for developing environmentally-friendly agriculture because rice is main crop in Korea and rice cultivation have both functions of water pollution and purification with environmental and cultivation conditions. This paper presents the evaluation of nitrogen impact by rice cultivation on water system. A simple protocol was proposed to assess the potential amount of nitrogen outflow from paddy field and most of parameters affect on the nitrogen outflow from paddy field such as the amount of fertilizer application, water balance, the quality and quantity of irrigation water, soil properties, nitrogen turnover in the soil and cultivation method were considered. To develop the protocol, coefficients for parameters affected nitrogen turnover and outflow were gotten and summarized by comparison and analysis of all possible references related, and by additional experiments at field and laboratory. And potential amount of nitrogen input and output by water in paddy field were estimated with the protocol at the conditions of the nitrogen contents of irrigation water, amount of fertilizer application, and irrigation methods. Where irrigation water was clean, below 1.0 mg of nitrogen concentration, rice cultivation polluted nearby watershed. At the conditions of 2.0 mg of nitrogen concentration, 110 kg of nitrogen fertilizer application and flooding irrigation, rice cultivation had water pollution function, but it had water purification function with intermittent irrigation. At the conditions of 3.0 mg of nitrogen concentration and 110 kg of nitrogen fertilizer application, rice cultivation had water purification function, but that had water pollution function with 120 kg of nitrogen application. Where irrigation water was polluted over 6.0 mg of nitrogen, it was evaluated that rice cultivation had water purifying effect, even though the amount of nitrogen application was 120 kg .

Numerical study on biological water purification functions of lakes and attached sublakes using a lake ecosystem model

Numerical study on biological water purification functions of lakes and attached sublakes using a lake ecosystem model

Investigatioh of Conditions Required to Construct an Artificial Shallow Area to Recover the Water Purification Function of a Hypoxic Sea

Investigatioh of Conditions Required to Construct an Artificial Shallow Area to Recover the Water Purification Function of a Hypoxic Sea

Field examination on reed growth, harvest and regeneration for nutrient removal

A wetland where aquatic macrophytes grow is expected to have the function of water purification. Nutrients assimilated by them are removed from the water by harvesting those plants. In order to carry out harvesting to remove nutrients effectively, it is essential to know the life cycle behavior of the plants. In this study, the characteristics of reed growth and regrowth after harvest were examined in the actual field. The height and number of the shoots, the standing biomass and nutrient contents were observed. The average height of living shoots reached its maximum when total sunshine duration was 500 hours since harvest. Nutrient contents showed the maximum value in the early growth stage. On the basis of these results, the numerical simulation model about the life cycle of the aboveground part of reed was developed to investigate nutrient removal efficiency by various harvest methods. It was recommended to harvest twice a year for the effective nutrient removal.

Field examination on reed growth, harvest and regeneration for nutrient removal

A wetland where aquatic macrophytes grow is expected to have the function of water purification. Nutrients assimilated by them are removed from the water by harvesting those plants. In order to carry out harvesting to remove nutrients effectively, it is essential to know the life cycle behavior of the plants. In this study, the characteristics of reed growth and regrowth after harvest were examined in the actual field. The height and number of the shoots, the standing biomass and nutrient contents were observed. The average height of living shoots reached its maximum when total sunshine duration was 500 hours since harvest. Nutrient contents showed the maximum value in the early growth stage. On the basis of these results, the numerical simulation model about the life cycle of the aboveground part of reed was developed to investigate nutrient removal efficiency by various harvest methods. It was recommended to harvest twice a year for the effective nutrient removal.

ＮＨ３‐Ｎの硝化によるＢＯＤ５値への影響

BOD5 is an index used for evaluation of water environment and purification function of wastewater treatment facilities. This value indicates bio-chemical oxygen demand consuming by organic matter. However, the BOD5 measurement is affected by oxygen demand of nitrification and BOD5 sometimes indicates an abnormal higher value compared with COD(Mn).By examining the trend of DO, NOx-N in incubation bottles and analyzing the change of effluent water quality in wastewater treatment facilities, we obtained some results shown bellow.1. The nitrification in incubation bottle occurred in initial 2 days for cultivation period of 5 days and observed exponential increase of nitrate.2. The BOD5 values of effuents from wastewater treatment facilities often observed larger than the COD(Mn) value and sometimes take 3 times higher than COD(Mn) value.3. The reaction rate of nitrification in incubation bottle was affected by NH3-N concentration. At the higher concentration of NH3-N in BOD5 measurement sample, the rate was in inverse proportion to NH3-N concentration. At the lower NH3-N concentration, however, it was in direct proportion to NH3-N concentration.In case of being affected by nitrification in BOD5 measurement, it is difficult to evaluate effluent water quality and purification function of wastewater treatment facilities by effluent BOD5. So it is necessary to measure the values of ATU-BOD, NH3-N, NO2-N, NO3-N with BOD5 measurement for biological treatment effluents.