Integrating Seasonal Dynamics and Wastewater Treatment with Biomass Production of Lemna gibba L. for Sustainable Water Remediation

This study investigates the potential of Chlorococcum aquaticum, a green microalga, for wastewater treatment and biomass production. Although microalgae-based bioremediation is well established, limited studies have comparatively evaluated the performance of C. aquaticum across multiple real wastewater types under identical experimental conditions, particularly using locally available wastewater sources. Four types of wastewater-agricultural, automotive, domestic, and laboratory-were tested to assess algal growth and pollutant removal over 14 days. The experiment was conducted under controlled laboratory conditions, with a standardized initial inoculum concentration adjusted to an optical density (OD750) of 0.1. It was performed under normal daylight conditions with a uniform light regime to ensure comparability among treatments, and at room temperature (30±1 °C). Key parameters analyzed included Chemical Oxygen Demand (COD), Total Dissolved Solids (TDS), Dissolved Oxygen (DO), heavy metal content (lead, Pb), and pH levels. Automotive wastewater supported the highest algal biomass production, yielding 1.89 g of dry weight, followed by agricultural wastewater, which yielded 1.05 g. In contrast, domestic and laboratory wastewater showed lower growth rates, while the control culture (algae+BBM) produced the least biomass at 0.84 g. The study revealed significant reductions in COD across all wastewater types, with automotive wastewater showing the highest COD reduction from 523.2 mg/L to 345.9 mg/L. Lead (Pb) removal was most effective in automotive sewage, with a decrease of 0.305 mg/L, followed by agricultural wastewater at 0.27 mg/L. Dissolved oxygen levels increased due to algal photosynthesis, while pH remained relatively stable, ranging between 7.03 and 8.36 across wastewater types. Total dissolved solids (TDS) showed minor fluctuations, with agricultural wastewater exhibiting the highest TDS at 165 mg/L. The findings demonstrate that Chlorococcum aquaticum can thrive in nutrient-rich wastewater environments while effectively removing pollutants, including heavy metals and organic contaminants. Based on the measured physicochemical parameters, treated agricultural, domestic, and automotive wastewater complied with the permissible limits for land application and irrigation as stipulated by Central Environmental Authority (CEA) guidelines. The harvested algal biomass holds promise for applications such as biofuel production, animal feed, and organic fertilizers. Future research should focus on detailed biochemical characterization of the algal biomass and optimization of cultivation parameters to enhance large-scale wastewater treatment efficiency and resource recovery. This study highlights the sustainable benefits of microalgae-based wastewater treatment systems. Keywords: Chlorococcum aquaticum, Wastewater treatment, Heavy metal removal, Biomass production, COD reduction

Subsurface Agricultural Drainage in California's San Joaquin Valley. Deciding on a Treatment Alternative. Current Options in Treatment of Agricultural Drainage Wastewater. Biotechnology in Environmental Engineering. Modern Biological Methods: The Role of Biotechnology. Bacterial Decontamination of Agricultural Wastewaters. Algae as Ideal Waste Removers: Biochemical Pathways. Algal Culture Systems. The Role of Microalgae in Removal of Selenate from Subsurface Tile Drainage. The Engineering of Microalgae Mass Cultures for Treatment of Agricultural Wastewater, with Special Emphasis on Selenium Removal from Drainage Waters. Is There an Uncertainty Principle in Microbial Waste Treatment? Biological Treatment: An Entrepreneurial Opportunity. Reviews the state-of-the-art of biological treatment of agricultural wastewater Stimulates the exchange of technical information Assesses historically proven systems and new approaches Promotes further development of technology

Treatment of Agricultural Wastewater in Downflow Reed Beds: Experimental Trials and Mathematical Model

The Egyptian water crisis has encouraged the exploration of innovative solutions for wastewater treatment. One promising approach is using treated agricultural drainage water for its large amount per year and low pollution. There are many methods used for the treatment of wastewater, but this research focused on a new one which is the use of microalgae for in-situ treatment of wastewater, due to its ability to uptake and adsorb pollutants, aerate water, and produce biomass for potential use as a biofuel or fertilizer. Microalgae have shown great potential for removing various pollutants from wastewater, including organic matter, nutrients, heavy metals, and pathogens. Moreover, the use of microalgae for wastewater treatment can be more cost-effective and sustainable than traditional wastewater treatment methods, which often require large and expensive infrastructure. This study aimed to investigate the effectiveness of using microalgae for in-situ treatment of agricultural drainage wastewater of Bahr El-Baqar drain. The results revealed that the removal efficiencies were 29% for BOD (biochemical oxygen demand), 46.9% for COD (chemical oxygen demand), 56.1% for TSS (total suspended solids), 31% for HM (Heavy Metal) removal, and 86% increment in DO (Dissolved Oxygen) concentration. This experiment provided evidence that microalgae could be a promising and cost-effective solution for in-situ treatment of agricultural drainage wastewater, with high removal efficiencies for pollutants in wastewater and the potential to reduce the need for constructing large and expensive wastewater treatment plants.

Flanders is one of the most populated regions in Europe where agriculture is large-scale and intensive. It is therefore challenged by high nutrient loads which deteriorate the surface water quality through direct discharge from wastewater treatment plants and through runoff from agricultural fields. According to our survey, constructed wetlands are in Flanders mainly used to treat domestic and agricultural wastewater in rural areas. The use of constructed wetlands as individual treatment systems has increased in the last years due to the obligation of wastewater treatment at remotely located households. In this overview, the performance of constructed wetlands treating municipal wastewater and manure treatment wastewater is analyzed. In general, the constructed wetlands studied were found to meet the limits set in the Flemish legislation for wastewater effluent quality. Many of the wetlands treating municipal wastewater are, however, dealing with high nitrogen loading which results in low total nitrogen removal efficiency. Also the phosphorus removal capacity in these wetlands was found to be limited. Therefore, these wetlands do not majorly decrease the nutrient discharge to the environment. The constructed wetlands treating manure treatment wastewater are, on the contrary, over-dimensioned and thus able to achieve excellent nutrient removal efficiency.

Comprehensive review on co-integration of conventional systems and advanced oxidation processes for industrial and agricultural wastewater treatment applications

Plant species have an important role in eco-ditches; however, the Michaelis-Menten kinetic parameters of nutrient uptake, growth rate and purification efficiency of ditch plants and their influences on domestic sewage treatment efficiency are still unclear. Growth rates of all nine species, but especially Lemna gibba, Cladophora and Myriophyllum verticillatum were best in undiluted domestic sewage as opposed to a mixture of domestic sewage. Performance of species to accumulate nutrients was not only species-specific, but was also affected by both sewage treatments. Removal efficiency of nutrients was dependent on both plant species and treatment. Uptake kinetic parameters were significantly affected by both nutrient form and plant species. The maximum uptake rate (Vmax) of NH4-N was higher than NO3-N. Similarly, Km values for NH4-N were greater than NO3-N. These results could be used to identify plants for sewage treatment efficiency and enhance water quality in eco-ditch treatment systems.

Domestic wastewater contains chemical compounds that can be used as nutrients for microalgae. Removing these chemical compounds from wastewater by microalgae might help in reducing the operation cost of wastewater management while minimizing the cultivation cost for large-scale microalgae metabolite production. In this study, domestic wastewater collected from Indah Water Konsortium (IWK), Kuala Lumpur, Malaysia, was assessed as growth media for two types of microalgae, namely Chlorella vulgaris and Haematococcus pluvialis. The biomass growth and nutrient removal efficiency of total nitrogen (TN), total phosphorus (TP), and total ammonia (TAN) in different concentrations of diluted wastewater were measured. The results showed that biomass concentration (0.227 g/L), biomass productivity (0.029 g/L/day), and specific growth rate (0,284 d-1) yielded by C. vulgaris in 14 days of 80% wastewater were comparable to those microalgae grew in standard Bold’s Basal medium (BBM). Besides, C. vulgaris grew in 50% wastewater to remove TN, TP, and TAN with the highest removal efficiency (>88%). For H. pluvialis, the biomass concentration in all wastewater concentrations was lower than BBM. The removal efficiencies of TN and TP were lower than 55%, but more than 80% for removal efficiency of TAN in 50% and 80% wastewater. Hence, C. vulgaris has better growth performance and nutrient removal efficiency than H. pluvialis. These findings indicated that IWK domestic wastewater could be used as growth media for microalgae, especially C. vulgaris.

Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

Currently, there is a growing concern regarding water remediation from agricultural and domestic wastewaters. Among water treatment methods, flocculation is a widely used approach. In this study, the bioflocculation of wastewaters from Sinaloa (Mexico) was examined using two bioflocculants: chitosan and bean straw flour (BSF). The jar-test results showed that chitosan exhibited high effectiveness in pollutant removal from different sampling zones (agricultural wastewater and river water). Additionally, this bioflocculant reduced remarkably the concentration of Mn and Fe. On the other hand, BSF showed high effectiveness in pollutant removal for a specific type of wastewater, being highly competitive as compared to chitosan. Besides, BSF led to 40% of Mn removal from highly contaminated river water samples. For both biomaterials, bioflocculation was driven by charge neutralization and sweep flocculation mechanisms. For a given agricultural wastewater sample, both bioflocculants performed better than the commercial poly(aluminum chloride) for pH regulation and Fe removal.

Valorization of wastewater: A paradigm shift towards circular bioeconomy and sustainability

Fine sieves can be implemented as compact alternatives to primary clarification. Fine sieved fraction (FSF) is a heterogeneous substrate that mainly consists of fibers originating from toilet paper and thus contains a high cellulosic fraction. Resource recovery and energy neutral sewage treatment is nowadays focus of many water authorities. This novel concept led to a new focus on optimisation of digestion processes and enhanced biogas production. In this scope, the main objective of this research was to investigate the bio-methane potential and maximum methane production rates of FSF, sequestered from raw municipal sewage, for onsite energy recovery towards energy neutrality at wastewater treatment plants. Main published chapters of this thesis: o Digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage (Chapter 2,Water Research, 2015). o Microbial population dynamics during long term sludge adaptation of thermophilic and mesophilic sequencing batch digesters treating sewage fine sieved fraction at varying organic loading rates (Chapter 3, Biotechnology for Biofuels, 2015). o High-rate thermophilic bio-methanation of the fine sieved fraction from Dutch municipal raw sewage: Cost-effective potentials for on-site energy recovery (Chapter 4, Applied Energy, 2016). o Comparative analysis of digestibility of sewage fine sieved fraction and virgin and recycled hygiene paper (Chapter 5, Waste Management, 2016). o Impact of lignocellulosic-waste intermediates on hydrolysis and methanogenesis under thermophilic and mesophilic conditions (Chapter 6, Chemical Engineering Journal, 2016).

Water resources, as critical ecological and environmental assets, are essential to the social and economic development of countries and regions worldwide. The Jinzi River valley functions as a discharge area for industrial and domestic sewage from mining operations and residential communities along both banks. However, due to human activities, both groundwater and surface water in the region have been contaminated to varying extents. Multiple gold mines are located in the research area. Due to years of unregulated mining, this has had a serious impact on the local ecological environment and water quality. However, research on groundwater and surface water in this region, which are crucial components of the ecological environment, remains limited. This study integrates local socio-economic and hydrogeological conditions, employing methods such as multivariate statistical analysis, the Piper trilinear diagram, the Gibbs model, and ionic ratio relationships to analyze the characteristics and origins of major ions in the region. (1) The primary hydrochemical type of surface water was HCO3-Ca·Na, while groundwater was predominantly of the HCO3-Ca·Mg type. This hydrochemical pattern was consistent across the region, with ion concentrations significantly higher in areas dominated by carbonate rock compared to those with silicate rock. (2) Using principal component analysis, water–rock interaction modeling, and ion source analysis, it was determined that groundwater chemistry was primarily influenced by the weathering of diorite and carbonate rock, along with inputs from domestic and agricultural wastewater. In contrast, surface water chemistry was largely controlled by the weathering of carbonate rocks and the discharge of industrial wastewater. (3) Components such as SO42−, NO3−, Cl−, and total dissolved solids in surface water exhibited a pronounced sensitivity to human activities, with their concentrations significantly exceeding those in groundwater. This indicates that surface water is more heavily impacted by human activities, particularly from industrial, agricultural, and domestic wastewater sources.

Afield experiment was carried out for two consecutive winter (rabi) seasons of2013-14 and 2014–15 at Kanpur, India to find out the effect of integrated nitrogen management (INM) on growth dynamics and nutrient content of winter maize (Zea mays L.) intercropped with potato (Solanum tuberosum L.), Indian mustard [Brassicajuncea (L.) Czernj. & Cosson] and linseed (Linum usitatissimum L.) for Indo-Gangetic plains of Uttar Pradesh. The experiment consisted of three intercropping systems (maize + potato, maize + mustard and maize + linseed grown in 3: 1 row ratio) and three INM practices, viz. 100% recommended dose of nitrogen (100% RDN), 75% RDN through inorganics + 25% RDN through organics (75 + 25% RDN), and 50% RDN through inorganics + 50% RDN through organics (50 + 50% RDN) along with sole cropping of maize, potato, mustard and linseed. Results revealed that dry matter accumulation increased progressively due to each crop growth stage. Maize + potato (3: 1) intercropping system resulted in the highest dry matter accumulation plant−1 throughout the crop growth, followed by maize + linseed (3: 1). Amongst different INM practices, treatment with 75 + 25% RDN revealed the maximum dry matter accumulation plant−1 and plant height. Maize + potato intercropping system exhibited higher absolute growth rate (AGR) and crop growth rate (CGR) during all the stages of crop growth, followed by maize + linseed system. Maize + potato also recorded higher relative growth rate (RGR) throughout the crop growth, except between 90 to 120 days after sowing (DAS). Maize+mustard intercropping system recorded lesser values of AGR, CGR and RGR throughout the crop period. INM practices improved the AGR and CGR but RGR was improved during later growth stages (120 days onwards) only. Application of 75 + 25% RDN recorded higher values of AGR and CGR. This treatment (75 + 25% RDN) also improved the RGR up to 90 DAS but between 90 to 120 DAS application of 75 + 25% RDN lowered RGR as compared to 100% RDN; however RGR further improved during later growth stages (120 days onwards) due to application of 75 + 25% RDN. Application of 50 + 50% RDN recorded minimum values of these growth indices. Correlation studies indicated significant positive correlation of seed yield with DMA, AGR, CGR and RGR as well as combinations of most of the growth stages, except RGR 90–120 DAS, emphasizing the importance of higher growth rate during grand growth period for best yield accrual in winter maize.

Comparison of semi-natural and constructed wetlands for agricultural wastewater treatment