Effectiveness of a Constructed Wetland with Carbon Filtration in Reducing Pesticides Associated with Agricultural Runoff

The Salinas Valley in Monterey County, California, USA, is a highly productive agricultural region. Irrigation runoff containing pesticides at concentrations toxic to aquatic organisms poses a threat to aquatic ecosystems within local watersheds. This study monitored the effectiveness of a constructed wetland treatment system with a granulated activated carbon (GAC) filter installation at reducing pesticide concentrations and associated toxicity to Ceriodaphnia dubia, Hyalella azteca, and Chironomus dilutus. The wetland was supplied with water pumped from an impaired agricultural and urban drainage. Across five monitoring trials, the integrated system’s average pesticide concentration reduction was 52%. The wetland channel and GAC filtration components individually provided significant treatment, and within each, pesticide solubility had a significant effect on changes in pesticide concentrations. The integrated treatment system also reduced nitrate by 61%, phosphate by 73%, and turbidity by 90%. Input water was significantly toxic to C. dubia and H. azteca in the first trial. Toxicity to C. dubia persisted throughout the system, whereas toxicity to H. azteca was removed by the channel, but there was residual toxicity post-GAC. The final trial had significant input toxicity to H. azteca and C. dilutus. The channel reduced toxicity to H. azteca and removed toxicity to C. dilutus. GAC filtration reduced H. azteca toxicity to an insignificant level. There was no input toxicity in the other three trials. The results demonstrate that a wetland treatment system coupled with GAC filtration can reduce pesticide concentrations, nutrients, suspended particles, and aquatic toxicity associated with agricultural runoff.

A Literature Review of Wetland Treatment Systems Used to Treat Runoff Mixtures Containing Antibiotics and Pesticides from Urban and Agricultural Landscapes

Wetland treatment systems are used extensively across the world to mitigate surface runoff. While wetland treatment for nitrogen mitigation has been comprehensively reviewed, the implications of common-use pesticides and antibiotics on nitrogen reduction remain relatively unreviewed. Therefore, this review seeks to comprehensively assess the removal of commonly used pesticides and antibiotics and their implications for nitrogen removal in wetland treatment systems receiving non-point source runoff from urban and agricultural landscapes. A total of 181 primary studies were identified spanning 37 countries. Most of the reviewed publications studied pesticides (n = 153) entering wetlands systems, while antibiotics (n = 29) had fewer publications. Even fewer publications reviewed the impact of influent mixtures on nitrogen removal processes in wetlands (n = 16). Removal efficiencies for antibiotics (35–100%), pesticides (−619–100%), and nitrate-nitrogen (−113–100%) varied widely across the studies, with pesticides and antibiotics impacting microbial communities, the presence and type of vegetation, timing, and hydrology in wetland ecosystems. However, implications for the nitrogen cycle were dependent on the specific emerging contaminant present. A significant knowledge gap remains in how wetland treatment systems are used to treat non-point source mixtures that contain nutrients, pesticides, and antibiotics, resulting in an unknown regarding nitrogen removal efficiency as runoff contaminant mixtures evolve.

Treatment of combined coffee processing wastewater using constructed wetland/ Cyperus-ustulatus and Typha-latifolia plants process

<p>The research investigated wastewater discharges from wet coffee processing plant (WCPP) combined with tap water (TW) treated by using Cyperus-ustulatus plant (P1), Typha-latifolia plant (P2) wetland. The WCPP wastewater was conducted by different combination (100%WW + 0% TW; 75% WW + 25% TW; 50% WW + 50% TW; 75%WW + 25% TW and 0% WW + 100% TW) after being irrigated for 21 days in the constructed wetland with P1, P2and control (without a plant). The highest value of total solids, chemical oxygen demand and biochemical oxygen demand increases were 76%, 95% and, 96%, respectively, removed wastewater treated by T3 (50% WW + 50% TW) with P2 wetland after 21 days irrigated. As a result, the combination of coffee wastewater with constructed wetland treatment methods was a low-cost, affordable, technically viable and eco-friendly treatment option for the wet coffee processing plant wastewater.</p>

Performance of Filterbeds and Macrophytes in Vertical Constructed Wetland for Treating Domestic Sewage Effluent

An experiment with different filterbeds and macrophytes was carried-out to study their phytoremediation capacity on the efficiency of domestic wastewater treatment through constructed wetland (CW) during November to March, 2017-18 at University of Agricultural Sciences, Dharwad campus, Karnataka, India. Twenty treatment combinations involving five types of filterbeds (FB-1: gravel, FB-2: gravel-sand-gravel, FB-3: gavel-sand-brick-gravel, FB-4: gravel-sand-charcoal-gravel and FB-5: gravel-sand-(charcoal+brick)-gravel) and four macrophytes (MP-1: Typha latifolia, MP-2: Brachiaria mutica, MP-3: Canna indica and MP-4: Phragmites sps.) were evaluated for treating domestic wastewater. After 120 days from start, across treatment combinations, water electrical conductivity (EC), total dissolved and suspended solids (TDS-TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), sodium, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), bicarbonates, total nitrogen-phosphorus-potassium (N-P-K) and boron (B) were reduced by more than 40 per cent due to wetland treatment. The system enhanced the mineralization of organic nitrogen to ammoniacal nitrogen (NH4+-N) and nitrate nitrogen (NO3-N) fractions. Among filterbeds, Type-5 caused higher reduction in pH, EC, BOD, COD and Organic-N while, Type-4 proved efficient in removing total solids and lowering pH in the sewage effluent. The Type-3 filterbed removed more suspended solids, potassium and ammoniacal nitrogen. Among the macrophytes, Brachiaria (paragrass) removed more nitrogen and potassium while, Phragmites removed more nitrogen, phosphorus and boron. The flexibility of implementation allows the CW to be adapted to different sites with different configurations, being suitable as main, secondary or tertiary treatment stage.

Selection of organic materials potentially used to enhance bioremediation of acid mine drainage

Acid mine drainage (AMD), produced when sulfide minerals are subjected to oxygen and water, is one of the major issues in mining industries. Without proper management, AMD's release to the environment would cause seriously prolonged environmental and health issues, such as increases soil acidity and reduces water quality due to extremely low pH, high sulphate concentration, and heavy metal solubility. AMD treatments are divided into two categories, i.e., active treatment, conducted by applying a chemical to the AMD to neutralize pH and precipitate heavy metals; and passive treatment, which relies on biological and biochemical processes. The active treatment may provide an immediate effect, but costly and yet sustainable; meanwhile, passive treatment takes time to establish and to generate an effect, but it is more economical, sustainable, and environmentally friendly. The wetland system is an example of passive treatment. Therefore, this review focuses on passive treatments, especially the selection of organic materials used in constructed AMD wetland treatment. Organic materials play a central role in the wetland system, i.e., to chelate metal ions, remove sulphate from the solution, increase pH, and growth media for microbes, especially sulphate reducing bacteria (SRB) and plants are grown in the system. Overall, organic materials determine the effectiveness of the wetland system to neutralize AMD passively and sustainably.

VIABILIDADE DA FERTIRRIGAÇÃO POR PIVÔ CENTRAL COM USO DE EFLUENTES TRATADOS EM DIFERENTES NÍVEIS

O objetivo deste trabalho foi verificar a viabilidade econômica do uso de esgotos sanitários, tratados com diferentes níveis de eficiência, para fertirrigação por pivô central em cultivos de algodão e soja. O estudo foi desenvolvido por meio da simulação e comparação de dois projetos de tratamento de esgoto sanitário a serem instalados na cidade de Correntina (BA). Para os cálculos de viabilidade, utilizou-se a planilha eletrônica AmazonSaf. Foram propostos dois cenários para o tratamento de esgoto para posterior fertirrigação: cenário A (pré-tratamento seguido de lagoa anaeróbia) e cenário B (pré-tratamento seguido de sistema australiano de lagoas e polimento com a ecotecnologia dos wetlands). Observou-se que os custos totais foram maiores no cenário B, devido ao aumento no investimento com o tratamento via wetland. O aumento direto foi de 0,82%, com um período de retorno do investimento de 8,7 anos. Há viabilidade econômica em reutilizar o efluente sanitário tratado do município de Correntina para irrigação de algodão e soja, independentemente do sistema de tratamento a ser adotado, embora a complementação do processo com a instalação do sistema de wetland se faça vantajosa do ponto de vista econômico, ambiental e social. Palavras-chave: análise financeira; economia circular; fertirrigação; reuso; sustentabilidade. Feasibility of central pivot fertirrigation with the use of effluents treated at different levels ABSTRACT: The objective of this work was to verify the economic viability of using sanitary sewage, treated with different levels of efficiency, for central pivot fertigation in cotton and soybean crops. The study was developed through the simulation and comparison of two sanitary sewage treatment projects to be installed in the city of Correntina (BA). For feasibility calculations, the AmazonSaf spreadsheet was used. Two scenarios were proposed for the treatment of sewage for subsequent fertigation: scenario A (pre-treatment followed by anaerobic lagoon) and scenario B (pre-treatment followed by Australian pond system and polishing with wetland ecotechnology). It was observed that the total costs were higher in scenario B, due to the increase in investment with wetland treatment. The direct increase was 0.82%, with a payback period of 8.7 years. There is economic viability in reusing the treated sanitary effluent from the municipality of Correntina for irrigation of cotton and soy, regardless of the treatment system to be adopted, although complementing the process with the installation of the wetland system is advantageous from an economic point of view, environmental and social. Keywords: financial analysis; circular economy; fertigation; reuse; sustainability.

Size and resin fractionations of dissolved organic matter and characteristics of disinfection by-product precursors in a pilot-scale constructed wetland

Controlling the formation of disinfection by-products (DBPs) is a major issue in the drinking water industry, and understanding the characteristics of DBP precursors in treatment processes for micro-polluted raw water is key to improving water quality. In this study, a sampling program was undertaken to investigate the fate of dissolved organic matter (DOM) and the characteristics of DBP precursors in a pilot constructed wetland imitating the Yanlong Lake ecological project. Using XAD resin adsorption and ultrafiltration techniques, the dissolved organic carbon, UV254, and DBP formation potential (DBPFP) were measured in different DOM fractions in raw water and wetland effluents. After the constructed wetland treatment, the low molecular weight fraction (&lt;3 kDa) of DOM and DBPFP generally showed a decreasing trend along the water path, while the high molecular weight fraction (&gt;3 kDa) of DOM increased. The specific DBPFP (SDBPFP) was much higher in the &lt;1 kDa fraction than in the other fractions. Although the hydrophobic fraction of DOM was the most abundant in all stages of the wetland treatment, the SDBPFP of the hydrophilic fraction was higher than that of the hydrophobic fraction. Furthermore, compared with raw water, the DOC, UV254 and DBPFP in the treated wetland effluents increased; however, all of the chemical DOM fractions exhibited decreased SDBPFP in accordance with a decrease in the specific ultraviolet absorbance during wetland treatment. These conclusions indicate that the DOM produced by the wetland system may generate DBPs less readily compared with the DOM of raw water.

Sewage Treatment System Planning for Dianchi Urban Wetland Park in Kunming

Dianchi Lake urban wetland park in Kunming is an important component of Dianchi lakeside wetlands, it is of great significance to the urban development and ecological protection of Kunming. To solve the problem of non-point source pollution of Dianchi Lake basin, the Dianchi Lake Pan-Asian International Urban Wetland Park is taken as an example, the rapid artificial infiltration treatment system and the comprehensive constructed wetland treatment system were designed for Dianchi Lake urban wetland park, and various design parameters and its influencing factors have been analyzed. After the deep treatment by the treatment system, the water quality reached the standards of landscape water. The planning of water system for Dianchi Lake urban wetland park provides a reference for designing plateau lake urban wetland parks.

Sustainable Treatment of Landfill Leachate Using Constructed Wetlands

Sanitary landfilling is the major method of disposal of municipal solid waste (MSW) in developing countries. The disposal of MSW in landfills generates a large amount of highly toxic leachate, which has high potential hazards for the public, flora, fauna health and ecosystems. Advanced leachate treatment systems using biological and chemical treatment methods are recently implemented in developed countries, but high investment and operating costs restricted their application in most of the developing countries. To overcome this problem, an alternative sustainable treatment technology such as phytoremediation could be beneficial. The constructed wetland treatment system is an economical alternative for leachate treatment using local resources and is an energy-efficient technology. These green systems utilize anaerobic and aerobic reactions to break down, immobilize, or incorporate organic substances and other contaminants from polluted effluent. This chapter highlights the recent advances in the treatment of landfill leachates using constructed wetlands.