Removing Organic Matter and Nutrients from Pig Farm Wastewater with a Constructed Wetland System

Organic stabilization and methane production under different organic loading rates in UASB treating swine wastewater

This study proposes the was to evaluate the stability and methane production with organic load differents in an upflow anaerobic sludge blanket reactor (UASB) treating swine wastewater by methods of multivariate analysis. Four organic loads were used with average hydraulic holding times of one day. The methods of data analysis of linear regression, Pearson correlation, principal component analysis and hierarchical clustering analysis were used for understanding stability and methane production in the reactor. The highest concentrations of bicarbonate alkalinity of 683 mg L-1 CaCO3 and total volatile acids of 1418 mg L-1 HAc with maximum organic loading applied were obtained. The optimal stability conditions occurred at an intermediate and partial alkalinity ratio between 0.24 and 0.25 observed in initial phases with a chemical oxygen demand (COD) removal of 47-57%. Maximum methane production was 9.0 L CH4 d-1 observed with linear regression positive and occurred at the highest applied organic load, corresponding to the highest COD removal efficiency and increased microbial biomass. Positive and negative correlation between functional stability in anaerobic digestion showed regular activity between acids, alkalinity and organic matter removal. This fact was also proven by the analysis of principal components that showed three components responsible for explaining 83.2% of the data variability, and the alkalinity, organic matter influent and organic acids had the greatest effects on the stability of the UASB reactor. Hierarchical clusters detected the formation of five groupings with a similarity of 50.1%, indicating that temperature and pH were variables with unitary influences on data dimensionality.

Pollutant removal from swine wastewater and kinetics in constructed rapid infiltration system (CRI system)

The purpose of this paper is centred on the kinetics of removal of main pollutants in wastewater and to compared different hydraulic loading conditions of the constructed rapid infiltration system (CRI system) in terms of removal efficiencies, effluent concentrations, mass removal rate (MRR), and the first-order removal rate coefficient (k) of COD, TOC, NH₄⁺-N, TN, and TP. The results showed that the higher the hydraulic loading, the higher the effluent concentration. The results that synthesized hydraulic loading, effluent concentrations, removal efficiencies, and other conditions showed that the best hydraulic loading was 40 cm/d. When the hydraulic load was 40 cm/d, the effluent average concentrations of COD, TOC, NH₄⁺-N, TN, TP, Cu²⁺ and the removal efficiencies were 27.31 ± 16.40 mg/L, 86.11%, 10.55 ± 5.25 mg/L, 84.64%, 0.59 ± 0.87 mg/L, 99.60%, 143.31 ± 14.77 mg/L, 7.04%, 5.64 ± 1.38 mg/L, 79.20%, and 0.13 ± 0.47 mg/L, 97.51%, respectively. According to a kinetic study of the primary pollutants, the MRR increased with an increase in the hydraulic loading, except for ammonia nitrogen. CRI-3, CRI-4 were high significant correlated with ammonia nitrogen (with R²= 93.65% and R²= 95.03%, respectively), while CRI-2, CRI-3, and CRI-4 were high significant correlated with total nitrogen (with R²= 94.56%, R²= 96.70% and R²= 96.56% respectively).

In-depth performance study of an innovative decentralized multistage constructed wetland system treating real institutional wastewater

The performance of an innovative decentralized multistage constructed wetland (DMCW) treating institutional wastewater is studied covering three seasons. The DMCW system with Canna lily efficiently removed organics contaminants like COD and BOD, and nutrients from the wastewater, showing its dependency on meteorological factors. Overall the performance is maximum in summer and least in monsoon, with a COD removal of 85.6% in summer followed by 82.5% in winter and 61.2% in monsoon. Removal of TSS (67.7-85.5%), PO₄^3--P (52.1-64.4%), NH₄⁺-N (56.6-71.6%), NO₃^--N (47.3-63.4%) and NO₂^--N (62-75.4%) were achieved along with heavy metals like Cr, Mn, Fe, Ni, Cu, Zn, As, Cd, Hg and Pb. Removal of pathogens like Vibrio is >98%, E. coli 95%, Pseudomonas 99%, and Aeromonas 63% was observed. Mass removal rate of COD was maximum in summer (97.3 g/m²/d) followed by winter (78.7 g/m²/d) and monsoon (43.5 g/m²/d). Majority of organics removal during the treatment was highlighted through Gas Chromatography-Mass Spectrometry (GCMS) and Fourier Transform Infrared Spectroscopy (FTIR) confirmed wastewater to be complex. The Canna lily accumulated various elements and oxides during the treatment with no stress on its health. The treated water quality is within the permissible limits and stands suitable for irrigational purposes. Better plant health and increased microbial diversity in the garden proves the suitability of treated water for irrigational activities. The results were validated using statistical tools like Mann-Whitney U test and principal component analysis.

Constructed wetlands for textile wastewater remediation: A review on concept, pollutant removal mechanisms, and integrated technologies for efficiency enhancement

Textile industries are among the ecologically unsustainable industries that release voluminous wastewater threatening ecosystem health. The constructed wetlands (CWs) are low-cost eco-technological interventions for the management of industrial wastewaters. The CWs are self-sustaining remediation systems that do not require an external source of energy and encompass simple operational mechanisms including biological (bioremediation and phytoremediation), chemical, and physical processes for pollutant removal. This review idiosyncratically scrutinizes the recent advances and developments in CWs, and their types employed for textile wastewater treatment. The major focus is on mechanisms involved during the removal of contaminants from textile wastewater in CWs and factors affecting the performance of the system. The article also discusses the State-of-the-Art integrated technologies e.g., CW-MFCs/algal ponds/sponge iron coupled systems, for the performance and sustainability enhancement of CWs. All the important aspects together with the technology amalgamation are critically synthesized for establishing suitable strategies for CW-based textile wastewater treatment systems.

Performance intensification of constructed wetland technology: a sustainable solution for treatment of high-strength industrial wastewater

The objectives of this study were to: (1) assess the intensification of chemical oxygen demand (COD) and phosphate (PO₄-P) removal; and (2) generate a set of rate constants of COD degradation (k_COD) and phosphate (k_PO4-P) removal for the treatment of industrial wastewater (WW) using intensified adsorption beds. Two horizontal subsurface flow constructed wetlands (HSSFCWs) filled with coal ash and alum sludge and two conventional HSSFCWs packed with gravels were operated with different loadings of COD and PO₄-P at a hydraulic retention time (HRT) of 24 hrs at water depth of 0.40 m. The bed performance was analysed for COD and PO₄-P removal efficiency. The intensified HSSFCWs outperformed the control beds by a mean COD and PO₄-P removal efficiency of 43 and 49%, respectively. The progression of COD and PO₄-P removal along the system was fitted into the first-order plug flow model (K-C model). In this study the k_COD values ranged from 0.36 to 0.65 m/d with a mean of 0.46 ± 0.08 m/d (n = 30). The k_PO4-P values ranged from 0.74 to 1.76 m/d and averaged to 1.23 ± 0.37 m/d (n = 30), irrespective of the condition applied. Hence, these data can be used for future projects using HSSFCWs to treat industrial wastewater.

Simultaneous Carbon and Nitrogen Removal from Domestic Wastewater using High Rate Vermifilter

Being a cost-effective and environmentally benign technology, vermifiltration has significantly replaced the available conventional wastewater remediation methods in many cases over the last few decades. The present work emphasizes on the investigation of the nitrogen transformation dynamics, in addition to the organic carbon abatement in the designed high rate hybrid vermifilter. Moreover, the economical sustainability of the vermifiltration technology has also been enlightened by creating a bridge with the concept of circular bio-economy. The designed high rate macrophyte-assisted vermifilter (MAVF) ascertained significant high nitrogen and organic carbon removal efficiencies from the real domestic sewage, considering the chemical oxygen demand (COD) of the influent and hydraulic loading rate (HLR) as the input variables. The designed MAVF facilitated the maximum ammonium nitrogen (NH4 +-N), organic nitrogen, and total kjeldahl nitrogen removal efficiencies up to 98.2 ± 0.70%, 100%, and 99 ± 0.47%, respectively when COD of the influent and HLR were 200 ± 25 mg/L and 3 ± 0.1 m3/m2-d, respectively. On the other hand, substantial enhancement in the nitrate nitrogen (NO3 --N) in the effluent (73 ± 10.55 times its influent concentration) was observed with influent COD of 200 ± 25 mg/L and HLR of 7 ± 0.2 m3/m2-d. When the influent COD and HLR were maintained at 700 ± 45 mg/L and 3 ± 0.1 m3/m2-d, respectively, the highest total nitrogen removal of 87 ± 2.25% was obtained. Alternatively, the influent COD of 200 ± 25 mg/L and HLR of 3 ± 0.1 m3/m2-d yielded the highest COD removal efficiency of 77 ± 1.59%. Hence, the outcome of the present research work strengthens the suitability of the vermifiltration technology as an economically and ecologically sound natural wastewater bio-remediation technology for the treatment of domestic wastewater.

Constructed wetland, an eco-technology for wastewater treatment: A review on types of wastewater treated and components of the technology (macrophyte, biolfilm and substrate)

Constructed wetland (CW) represents an efficient eco-technological conglomerate interweaving water security, energy possibility and environmental protection. In the context of wastewater treatment technologies requiring substantial efficiency at reduced cost, chemical input and low environmental impact, applications of CW is being demonstrated at laboratory and field level with reasonably high contaminant removal efficiency and ecological benefits. However, along with the scope of applications, role of individual wetland component has to be re-emphasized through related research interventions. Hence, this review distinctively explores the concerns for extracting maximum benefit of macrophyte (focusing on interface of pollutant removal, root radial oxygen loss, root iron plaque, endophyte-macrophyte assisted treatment in CW, and prospects of energy harvesting from macrophyte) and role of biofilm (effect on treatment efficiency, composition and factors affecting) in a CW. Another focus of the review is on recent advances and developments in alternative low-cost substrate materials (including conventional type, industrial by-products, organic waste, mineral based and hybrid type) and their effect on target pollutants. The remainder of this review is organized to discuss the concerns of CW with respect to wastewater type (municipal, industrial, agricultural and farm wastewater). Attempt is made to analyze the practical relevance and significance of these aspects incorporating all recent developments in the areas to help making informed decisions about future directions for research and development related to CW.

Assessing the Effects of Land Use on Surface Water Quality in the Lower uMfolozi Floodplain System, South Africa

This study investigated the impacts of cultivation on water and soil quality in the lower uMfolozi floodplain system in KwaZulu-Natal province, South Africa. We did this by assessing seasonal variations in purposefully selected water and soil properties in these two land-use systems. The observed values were statistically analysed by performing Student’s paired t-tests to determine seasonal trends in these variables. Results revealed significant seasonal differences in chloride and sodium concentrations and electrical conductivity (EC) and the sodium adsorption ratio (SAR) with cultivated sites exhibiting higher values. Most of the analyzed chemical parameters were within acceptable limits specified by the South African agricultural-water-quality (SAWQ) water quality guidelines for irrigation except for sodium adsorption ratio (SAR), chloride, sodium and EC. EC, pH and nitrate content which were higher than the specified SAWQ limits in cultivated sites. Quantities of glyphosate, ametryn and imidacloprid could not be measured because they were below detectable limits. The study concludes that most water quality parameters met SAWQ’s standards. These results argue for concerted efforts to systematically monitor water and soil quality characteristics in this environment to enhance sustainability by providing timely information for management purposes.

Constructed Wetlands in Latin America and the Caribbean: A Review of Experiences during the Last Decade

The review aims to report the state-of-the-art constructed wetlands (CW) in the Latin America and Caribbean (LAC) region not limited to national and local conditions. The aim is with a broader view, to bring updated and sufficient information, to facilitate the use of the CW technology in the different countries of LAC. Thus, 520 experiences extracted from the 169 reviewed documents in 20 countries were analyzed. According to the data, horizontal subsurface flow wetlands are the most reported CW in the region (62%), the second most common CW technology in the region is free water surface CW (17%), then vertical flow systems (9%), followed by intensified constructed wetlands (8%), and finally French systems (4%). The performance for nutrient removal is analyzed, finding that the mean of Chemical Oxygen Demand (COD), Total Nitrogen (TN), and Total Phosphorous (TP) removal efficiencies varies from 65% to 83%, 55% to 72%, and 30% to 84%, respectively. The results suggest a generally good performance for COD and TN removal, but a low performance for TP removal. Regarding plant species used for CWs, 114 different plant species were reported, being until now the most extensive report about plant species used in CWs in the LAC region.

Emerging pollutants-Part II: Treatment

Recently, emerging pollutants (EPs) have been frequently detected in urban wastewater, surface water, drinking water, and other water bodies. EPs mainly usually include pharmaceuticals and personal care products, endocrine-disrupting chemicals, antibiotic resistance genes, persistent organic pollutants, disinfection by-products, and other industrial chemicals. The potential threat of EPs to ecosystems and human health has attracted worldwide attention. Therefore, how to treat EPs in various water bodies has become one of the research priorities. In this paper, some research results on treatment of EPs published in 2018 were summarized. PRACTITIONER POINTS: At present, more attention has been paid to emerging pollutants (EPs), including pharmaceuticals and personal care products (PPCPs), endocrine-disrupting chemicals (EDCs), antibiotic resistance genes, persistent organic pollutants, disinfection by-products, etc. Existing EPs disposal technologies mainly include: engineered wetlands and natural systems, biological treatment, physical and physicochemical separation, chemical oxidation, catalysis, etc. This paper reviews some research results on the treatment technologies of EPs published in 2018.