Application Of Reclaimed Water Research Articles

Nutrient leaching potential along a time series of forest water reclamation facilities in northern Idaho

Forest water reclamation is a decades-old practice of repurposing municipal reclaimed water using land application on forests to filter nutrients and increase wood production. However, long-term application may lead to nutrient saturation, leaching, and potential impairment of ground and surface water quality. We studied long-term effects of reclaimed water application on nutrient leaching potential in a four-decade time series of forest water reclamation facilities in northern Idaho. Our approach compared reclaimed water treated plots with untreated control plots at each of the forest water reclamation facilities. We measured soil nitrifier abundance and net nitrification rates and used tension lysimeters to sample soil matrix water and drain gauges to sample from a combination of matrix and preferential flow paths. We determined nutrient leaching as the product of soil water nutrient concentrations and model-estimated drainage flux. There was more than 450-fold increase in nitrifier abundance and a 1000-fold increase in net nitrification rates in treated plots compared with control plots at long-established facilities, indicating greater nitrate production with increased cumulative inputs. There were no differences in soil water ammonium, phosphate, and dissolved organic nitrogen concentrations between control and effluent treatments in tension lysimeter samples. However, concurrent with increased nitrifier abundance and net nitrification, nitrate concentration below the rooting zone was 2 to 4-fold higher and nitrate leaching was 4 to 10-fold higher in effluent treated plots, particularly at facilities that have been in operation for over two decades. Thus, net nitrification and nitrifier abundance assays are likely indicators of nitrate leaching potential. Inorganic nutrient concentrations in drain gauge samples were 2 to 11-fold higher than lysimeter samples, suggesting nutrient losses occurred predominantly through preferential flow paths. Nitrate was vulnerable to leaching during the wet season under saturated flow conditions. Although nitrogen saturation is a concern that should be mitigated at long-established facilities, these forest water reclamation facilities were able to maintain average soil water nitrate concentrations to less than 2 mg L−1, so that nitrogen and phosphorous are effectively filtered to below safe water standards.

Effect of using reclaimed water via furrow and subsurface drip systems under alternate partial root-zone irrigation mechanism on crops growth and soil properties

AbstractThe growing population in the face of water scarcity inevitably necessitates the quest for alternative sources of irrigation water, which integrates them with irrigation strategies for improved agricultural productivity to meet the Sustainable Development Goals. A three-year field experiment was conducted in 2017, 2018, and 2019 to investigate the effect of water quality (reclaimed water (RW) and clean water (CW)), irrigation techniques (subsurface drip irrigation (SDI) and furrow irrigation (FUI)), irrigation methods (full irrigation (FI) and alternate partial root-zone irrigation (APRI) (70% ETc)), and their interactions on the fresh fruit yield (FY), irrigation water use efficiency (IWUE), and nitrogen use efficiency (NUE) of tomatoes. Further, electrical conductivity (EC), pH, and organic matter (OM) of soil were evaluated. The experiments were undertaken over three growing spring seasons in a greenhouse at the Chinese Academy of Agricultural Sciences in Henan Province, China. Throughout the three years of this study, the yield, the IWUE, and the NUE values of all treatments under RW were higher than those corresponding values under CW. The trend was the same under SDI as it was under FUI. Statistical analyses revealed that there was no significant effect (P > 0.05) of water quality, irrigation technique, and irrigation methods on the soil EC, pH, and OM over the three years. In addition, the interaction between the different experimental factors over the three years of the study was not significant. In conclusion, the application of RW under SDI can result in saving CW and increasing productivity without any negative effect on the investigated soil properties. Furthermore, when RW-SDI is used in conjunction with APRI, it can result in increasing IWUE.

Prioritization of organic contaminants in a reclaimed water irrigation system using wide-scope LC-HRMS screening

A prioritization procedure was developed and implemented at the local level to identify the most relevant organic contaminants of emerging concern (CECs) in an agricultural area irrigated with reclaimed water. A wide-scope screening methodology based on UPLC-HRMS analysis was applied to holistically characterize the CEC footprint in water and its spatial and temporal variations. One hundred and fifty-eight CECs, including pharmaceuticals, industrial chemicals, and pesticides, among others, were identified with a confidence level of 2 in the water samples investigated. After water treatment in the reclamation plant and transport within the irrigation channel network, more than a hundred compounds were still detected at the location where water is abstracted for crop irrigation. Compound ecotoxicity and occurrence (semi-quantified concentrations or peak intensity) were the parameters used to prioritize CECs in the water used for irrigation. Results pointed at venlafaxine, O-desmethyl-venlafaxine, galaxolidone, theophylline/paraxanthine, oxybenzone, and N-phenyl-1-naphtylamine, among others, as CECs of concern in the investigated area. This study provides a simple and cost-effective approach to detecting site-specific priority pollutants that could otherwise be overlooked by national or European regulations. The prioritization tool provided contributes to rationally designing monitoring and attenuation programs and efficiently managing water resources, by ensuring the safety of reclaimed water applications.

Simulation Study on the Optimisation of Replenishment of Landscape Water with Reclaimed Water Based on Transparency.

Water-scarce cities have fewer surface water (SW) resources available for ecological use, causing landscape water to deteriorate due to water shortage and fail to perform their intended landscape functions. As a result, many cities use reclaimed water (RW) to replenish them. However, this could cause concern among the people, as RW usually has higher nutrient concentrations, which may stimulate algae growth and deteriorate the aesthetic senses of the receiving water bodies. In order to assess the feasibility of using RW for this purpose, this study used Xingqing Lake in Northwest China as insight into the effect of RW replenishment on the visual landscape quality of urban landscape water. Water transparency (measured by SD) is used as an intuitive indicator to reflect the comprehensive influence of suspended solids and algae growth on the water's aesthetic quality. Scenario analyses were carried out after calibrating and validating one-year data in MIKE 3 software with both SD and algae growth calculations, and the results showed that the low concentration of suspended matter in RW could compensate for the decrease in SD due to algal blooms caused by high concentrations of nitrogen and phosphorus, and the effect on SD is especially pronounced under conditions that are not conducive to algal growth, such as good flow conditions and low temperature. In addition, to meet a SD ≥ 70 mm, the total water inflow required can be significantly reduced with the optimal application of RW. It is also indicated that partial or complete utilization of RW to replace SW for replenishing the landscape water could be feasible from the viewpoint of landscape quality, at least for the landscape water investigated in this study. This can provide a method for the improvement to urban water management practices by using RW for replenishment in water-scarce cities.

Tree Growth and Vegetation Diversity in Northern Idaho Forest Water Reclamation Facilities

Forest water reclamation can improve tree growth and renovate municipal wastewater. Although there are indications that long-term application may exceed forest assimilation capacity, there is limited information on the long-term effects of reclaimed water application on coniferous ecosystems. The purpose of our study was to assess the impacts of prolonged reclaimed water application on forest growth responses and vegetation diversity. We examined the effects of reclaimed water at five water reuse facilities established between 1978 and 2013 in a four-decade time series. We collected tree cores and stem measurements to determine current and retrospective increments. We assessed plant diversity with vegetation surveys. The greatest diameter response observed for reclaimed water amendment compared to controls was 166.1% for western redcedar, while Douglas-fir increased up to 116.4% and ponderosa pine increased up to 100.6%. The minimum response observed was 30.3%. Current annual increments showed that the basal area and volume were significantly greater at long-established facilities for reclaimed-water-amended plots. The understory vegetation diversity declined with application time, while overstory vegetation diversity increased with application time. We conclude that reclaimed water can be a valuable resource to improve forest productivity, but continued application without stocking control may have detrimental effects on forest growth and vegetation diversity.

Influence of Reclaimed Water Quality on Infiltration Characteristics of Typical Subtropical Zone Soils: A Case Study in South China

Irrigation with reclaimed water (RW) can alleviate water scarcity and improve the environmental and economic benefits. However, RW contains a large number of salts, suspended particles, organic matter, etc., which can affect soil infiltration. Previous studies focused on the examination of this effect in alkaline soils, but the infiltration change of acidic soils has seldom been investigated. This study selects four typical types of soil in the subtropical area in the south of China and designs experiments using different concentrations of RW to examine the influence of RW on the infiltration of various acid soils. The short-term impact is examined based on a one-dimensional horizontal method, and the long-term infiltration characteristics are measured by a Mini Disk infiltration meter with one year’s RW irrigation. Results show that RW irrigation can restrain the short-term infiltration of red soil while accelerating that of purple soil, aquic soil and paddy soil. Regarding the long-term effect, the cumulative infiltration of red soil increases with the decline of the concentration of RW, while there is no unique trend for the other soils. After one year’s RW irrigation, physical properties such as soil particle size distribution, texture and EC have changed. For red soil, EC increased significantly with RW irrigation, from 46.7 µS/cm to 101.07 µS/cm. However, regarding aquic soil, EC decreased from 157.05 µS/cm to 123.20 µS/cm. Moreover, the infiltration rate coefficient of red soil and aquic soil exhibits a significant positive correlation with RW concentration (p < 0.01), while the silt content shows a significantly negative correlation (p < 0.01). Furthermore, soil infiltration parameters c and S value of the purple soil, paddy soil, is significantly negative correlated with pH value (p < 0.01). The results reflected that appropriate RW quality for irrigation is different among various soil types, which will influence the sustainable application of RW. It can shed insights into solving the water scarcity issue and improving water sustainability in subtropical regions.

Reclaimed water application to vegetation restoration in mining area: Determination of water quality standards and optimization of moderate treatment technology

Water shortage severely restricts vegetation restoration of mining area in the northwest China. Moderate treatment of reclaimed water is essential for improving the local ecological environment. In this study, relevant water quality standards issued by the states and research results were comprehensively considered to propose a reclaimed water quality standard suitable for vegetation restoration of mining area. The available domestic sewage and mine water was moderately treated by hybrid biological reactor system and nanofiltration membrane system, respectively. The effluent quality meet the requirement of reclaimed water quality standards in this study. This study provides theoretical support for vegetation restoration of mining area.

Determination of log removal values of bacteria by spiral-wound reverse osmosis modules and a hollow fiber ultrafiltration module using Escherichia coli and indigenous heterotrophic bacteria as indicators.

The use of reverse osmosis (RO) membranes has been expanding not only to medical applications but also to water supply and reclaimed water applications due to its strong ability to remove a wide range of contaminants. Many researchers reported RO performance as a barrier against waterborne viruses; however, there are limited reports on its ability to remove bacteria from water. This investigation evaluated the removal performances of several spiral-wound RO modules and a hollow fiber ultrafiltration (UF) module in two different ways: dosing tests in batch-wise mode operation and in continuous-mode operation. The dosing tests of Escherichia coli using RO modules confirmed that E. coli could leak from the feed-side into the permeate. The log removal values (LRVs) (4.21- to >7.44-log10) by the RO modules from different production lots were found to vary greatly. In continuous-mode operation of the RO module, the LRVs for indigenous heterotrophic bacteria decreased over the operation period. These results clearly illustrate that bacteria, which originate on the feed-side, can leak into the permeate-side and then begin to proliferate in the permeate. On the other hand, using a UF module, E. coli was not detected in the permeate regardless of the operation mode.

Advancing Agricultural Water Security and Resilience Under Nonstationarity and Uncertainty: Evolving Roles of Blue, Green, and Grey Water

Advancing Agricultural Water Security and Resilience Under Nonstationarity and Uncertainty: Evolving Roles of Blue, Green, and Grey Water

Replenishment of landscape water with reclaimed water: Optimization of supply scheme using transparency as an indicator

With shortages of urban water resources, reclaimed water (RW) has become increasingly important as an alternative water source, especially for replenishing landscape waters. To meet the requirements of landscape quality control when RW is used for partial replacement of the surface water (SW) source to a channel-type urban water in a city in northwest China, scenario analyses were carried out by mathematical modelling. Water transparency (measured by SD) is used as an intuitive indicator to reflect the comprehensive influence of suspended solids (SS) and algae growth on the water’s aesthetic quality. Findings indicate that although the significantly higher nutrient concentrations of RW might bring about higher algae growth potential, in comparison with SW, its much lower SS concentration could offset the adverse effects on SD, to a large extent. By embedding the water quality model, calibrated and validated based on a two-year measurement data into MIKE 3 software for both SD and algae growth calculation, computer simulations were carried out to assist a series of scenario analyses of RW utilization and optimization of the water supply scheme. As a result, to meet the requirement of SD > 80 cm at the control section of the landscape water, the total water inflow required was not increased but decreased with the optimal application of RW. The advantages of lower SS in RW to reduce the demand inflow of total water was more evident with the higher requirement of SD. Replenishment of the channel-type urban water by RW was, thus, proven feasible from the viewpoint of landscape quality control.

Chemical Clogging Behavior in Drip Irrigation Systems Using Reclaimed Water

Abstract. Reusing reclaimed water in agricultural irrigation has become an effective way to alleviate water shortages in agriculture. However, the multiple substances in reclaimed water and their coupling effects easily lead to emitter clogging when using drip irrigation technology. The microorganisms present in reclaimed effluents secrete extracellular substances and absorb large amounts of solid particles, ions, nutrients, and organic matter and thus become the main part of the clogging substance. Meanwhile, traditional drip irrigation systems converted from irrigation to both irrigation and fertilization and the water-fertilizer coupling effects result in more chemical precipitation. Determining whether the chemical process has a significant impact on clogging and understanding the mechanism of this process was considered a difficult and important research question. For this reason, an indoor experiment, under a controllable environment, for drip irrigation emitter clogging using both reclaimed water with three Ca2++Mg2+ concentrations and groundwater was carried out. Several precise testing methods, such as x-ray diffraction, were applied to identify the mineral components in the clogging substances, and their characteristics and impacts on clogging were systematically explored. The results indicated that the emitter clogging characteristics were coincident under different treatments when using reclaimed water, and chemical precipitates were found in all treatments. Higher Ca2++Mg2+ concentrations led to more serious emitter clogging. The discharge ratio variation and Christiansen coefficient of uniformity for the reclaimed water treatments were lower than those for the groundwater treatment. Meanwhile, the total weights of the clogging substances were 5.6% to 58.8% higher. There were sufficient mineral components in the clogging substances, and they were identified as quartz, silicate, carbonate, and salt. Their contents all showed significant linear correlations with the degree of emitter clogging (R2 > 0.64, p < 0.05), which indicated that mineral components increased as the system continued operation. Among them, salt and silicate were linearly correlated to quartz contents, as they mainly originated from the water used for drip irrigation. However, carbonate contents increased in an exponential pattern with quartz contents (R2 > 0.67, p < 0.01), which demonstrated that carbonate was the main mineral component formed during the clogging process and the key component that increased clogging. The results obtained in this study provided insights into the chemical clogging process and the targeted chemical precipitates to be dealt with when using reclaimed water for drip irrigation. Keywords: Chemical precipitation, Emitter, Microirrigation clogging, Reclaimed water application.

Evaluation of Microbial Risk Assessment Techniques and Applications

This investigation reviewed and evaluated methodologies used for microbial risk assessment with respect to their applicability for reclaimed water applications. The investigation was comprised of five primary components: a comprehensive database of articles, reports and books describing microbial risk assessment methodologies was established and reviewed. Risk assessment techniques and models were identified for estimating the public health risk from exposure to microorganisms via reclaimed water applications. Two models were identified for further evaluation: a static (individual based) and a dynamic (population based).In the third component, the two models were evaluated to differentiate between the conditions under which models predict similar and substantially different estimations of risk. Through numerical simulation, exposure/pathogen combinations were identified when it may be appropriate to use the less complex, static model. Case study risk assessment scenarios demonstrated the model selection process for three realistic, yet hypothetical reclaimed water scenarios. The fourth component presents a constraint analysis for existing reuse regulations. The constraint analysis is carried out by documenting the existing reuse regulations. The constraint analysis is carried out by documenting the existing regs in three states for landscape irrigation and uses that comparison as a starting point to identify how microbial risk assessment may be useful within the context of existing and potential future water reuse regulations. The investigation concludes by identifying criteria for a computer interface that would allow regulatory and/or municipal agencies/utilities to take advantage of the analysis discussed in the report. This title belongs to WERF Research Report Series ISBN: 9781780404141 (eBook) ISBN: 9781843396840 (Print)

Energy analysis of reclaimed water application for irrigation in arid and semi-arid regions

Freshwater availability is the major constraint to agriculture in arid and semi-arid regions. The groundwater and energy conservation of applying reclaimed water for irrigation was analysed, using Southern California as the spatial domain for model testing. An extensive compilation of the most recent publicly available datasets was used to calculate the energy intensity for each water supply source, the associated carbon footprint reduction and the monetary savings associated with using reclaimed water over groundwater. Our results indicate that for 1998–2010 in California the fractional water use for agriculture is 0.81 and for urban use is 0.19. During this same period, an average of 4.2 × 1010 m3 of water were used for crop irrigation, of which 1%, 46.8% and 52.2% came from reclaimed water, groundwater, and surface water, respectively. Each of these three main water sources is associated with a range of energy intensity (in kWh m−3), depending on the process and environmental characteristics of the end-use location. Our analysis of multiple process and environmental configurations produced a detailed energy intensity database, with the associated carbon footprint. These databases are used to quantify the energy and carbon footprint difference between applying the current groundwater source and reclaimed water for irrigation.

Analysis on Garden Irrigation for the Recycling and Use of Reclaimed Water

The lack of water resource is the resource and environmental problem of various countries in the current international environment face, and a better way to solve the shortage of water resource is to adopt the reclaimed water for civil irrigation. But the development of science and technology in China started late, it leads to that our country doesnt have deep experience in the use of the reclaimed water application technology, thus, the development and requirements of this technology in the domestic world are very urgent and demanding. In this paper, the author makes a detailed technology requirement explanation for the technology requirement level of supervision, technology, technics and management aspect on wastewater reuse technology.

Long-term reclaimed water application effects on phosphorus leaching potential in rapid infiltration basins

Rapid infiltration basins (RIBs) are effective tools for wastewater treatment and groundwater recharge, but continuous application of wastewater can increase soil P concentrations and subsequently impact groundwater quality. The objectives of this study were to (1) investigate the effects of reclaimed water infiltration rate and "age" of RIBs on soil P concentrations at various depths, and (2) estimate the degree (percentage) of sorption equilibrium reached between effluent P and soil attained during reclaimed water application to different RIBs. The study was conducted in four contrasting cells of a RIB system with up to a 25 year history of secondary wastewater application. Soil samples were collected from 0 to 300 cm depth at 30 cm intervals and analyzed for water extractable phosphorus (WEP) and oxalate extractable P, Al, and Fe concentrations. Water extractable P and P saturation ratio (PSR) values were generally greater in the cells receiving reclaimed water compared to control soils, suggesting that reclaimed water P application can increase soil P concentrations and the risk of P movement to greater depths. Differences between treatment and control samples were more evident in cells with longer histories of reclaimed water application due to greater P loading. Data also indicated considerable spatial variability in WEP concentrations and PSR values, especially within cells from RIBs characterized by fast infiltration rates. This occurs because wastewater-P flows through surface soils much faster than the minimum time required for sorption equilibrium to occur. Studies should be conducted to investigate soil P saturation at deeper depths to assess possible groundwater contamination.

Soil Enzyme Activities of Long‐Term Reclaimed Wastewater‐Irrigated Soils

Studies have shown that physical and chemical properties of soils may be significantly changed when they are subjected to long-term reclaimed water irrigation. It remains unclear how reclaimed water application may affect nutrient cycling in soils. Soil enzymes are responsible for the biogeochemical cycling of many elements and are more sensitive indicators of the ecological changes. In this study, 17 soil enzymes, including those associated with the C, N, P, and S cycles and two oxidoreductases (catalase and dehydrogenase), were assayed in soils obtained from five long-term reclaimed wastewater irrigation sites in southern California. The soil enzyme activities varied widely among the sampling sites. Compared with their respective controls, the overall activities of enzymes involved in the cycling of the four elements in soil were enhanced by an average of 2.2- to 3.1-fold. Principal component analysis and cluster analysis indicated that the soil microbial functional diversity may be evaluated based on activities of catalase, alkaline phosphatase, acid phosphatase, dehydrogenase, and urease.

Water reuse criteria in the United States

Water reuse is well established in the United States, with uses ranging from pasture irrigation using reclaimed water that has received a low level of treatment, to augmentation of potable water supplies with highly treated reclaimed water. There are no federal regulations governing water reuse and criteria are developed at the state level. Criteria differ between states that have adopted regulations or guidelines, but criteria among states where water reuse is prevalent are similar and tend to be conservative, with public health protection being the most important consideration. The US Environmental Protection Agency (EPA) has published guidelines for water reuse that include recommended criteria for various reclaimed water applications.

Water reclamation and reuse criteria in the U.S.

Increasing demands on water resources for domestic, commercial, industrial, and agricultural purposes have made water reclamation and reuse an attractive option for conserving and extending available water supplies. Also, many water reuse projects are implemented to eliminate a source of contamination in surface waters or as a least-cost alternative to meeting stringent discharge requirements. Reclaimed water applications range from pasture irrigation to augmentation of potable water supplies. Water reclamation and reuse criteria are principally directed at health protection. There are no federal regulations governing water reuse in the U.S.; hence, the regulatory burden rests with the individual states. This has resulted in differing standards among states that have developed criteria. This paper summarizes and compares the criteria from some states that have developed comprehensive regulations. Guidelines published by the US. EPA and the rationale behind them are presented for numerous types of reclaimed water applications.

Water reclamation and reuse criteria in the U.S.

Increasing demands on water resources for domestic, commercial, industrial, and agricultural purposes we made water reclamation and reuse an attractive option for conserving and extending available water supplies. Also, many water reuse projects are implemented to eliminate a source of contamination surface waters or as a least-cost alternative to meeting stringent discharge requirements. Reclaimed water applications range from pasture irrigation to augmentation of potable water supplies. Water lamation and reuse criteria are principally directed at health protection. There are no federal regulations governing water reuse in the U.S.; hence, the regulatory burden rests with the individual tes. This has resulted in differing standards among states that have developed criteria. This paper nmarizes and compares the criteria from some states that have developed comprehensive regulations. Guidelines published by the US. EPA and the rationale behind them are presented for numerous types reclaimed water applications.