Use Of Water Treatment Residuals Research Articles

Liming and co‐application of water treatment residuals with biosolids for conditioning sandy soils

AbstractApplication of water treatment residuals (WTR) and biosolids (BS) might ameliorate fragile soils. However, studies integrating impacts of waste preparation methods such as liming and grinding associated with co‐application approaches for soil conditioning are lacking. The present study aimed to evaluate the feasibility of agricultural use of WTR as well as their co‐application with BS to ameliorate a sandy soil through assessing impacts on selected soil quality indicators and on nutrient and potentially toxic element concentration in plant tissue in addition to the biomass yield of annual crops. The following treatments were evaluated: non‐amended soil (control); drying plus grinding and liming WTR; WTR co‐application with BS at 3:1 ratio; and a soil amendment commercially available in Brazil. All treatments were soil incorporated in the 0.0–0.2 m layer at 30 Mg ha−1 dose (dry mass). Selected soil physical, hydraulic, and chemical parameters were determined. Furthermore, nutrients and potentially toxic elements concentration in plant tissue as well as the agronomic performance of maize and ryegrass were measured. The co‐application of WTR and BS increased the soil content of P, Zn, and Cu in the 0.0–0.1 m layer. The concentration of these nutrients also was greater in ryegrass tissue and promoted the biomass yield in 51%. WTR did not increase contaminants and did not decrease the P content in soil and in plant tissue, independently of drying plus grinding and liming. Considering the conditions investigated in our study, WTR/BS co‐application was environmentally safe and effective in ameliorating soil quality.

Adsorptive removal of Pb2+ and Cu2+ from stormwater by using water treatment residuals

ABSTRACT The removal of heavy metal ions from stormwater runoff is a global issue. One of the critical solutions is the selection of innovative adsorbent used in stormwater bioretention systems. The potential use of water treatment residuals (WTRs) containing polyaluminium chloride and anionic polyacrylamide to remove divalent lead ions (Pb2+) and divalent copper ions (Cu2+) from stormwater was investigated by batch adsorption experiments with respect to varying adsorption conditions. The maximum adsorption capacity was determined as 224.4 mg Pb2+/g WTRs and 89.0 mg Cu2+/g WTRs under acidic conditions. The adsorption process might be simultaneously controlled by surface adsorption and intraparticle diffusion. WTRs can be considered as an effective and promising media in stormwater bioretention systems to remove both ions due to its advantage of low cost, wide availability, and relatively large adsorption capacity. Further studies should be performed by using fixed bed columns at a pilot scale before field trials.

Use of water treatment residuals for colour removal from real textile dye wastewater

The use of readily available water treatment residuals (WTR) as a low-cost material for removal of colour from real textile wastewater was investigated. WTR was used in three forms, namely in raw wet form as a coagulant, in the dried form as an adsorbent and as a filtration media in column tests. The results showed a maximum colour removal of 55 and 36% by coagulation and adsorption, respectively, and the corresponding COD removals were 35 and 37%. Coagulation and batch sorption tests showed the effect of initial pH on the colour removal, and maximum colour removal was obtained at an initial pH of 3.0. Long-duration continuous-flow column test using WTR as a filtration/sorption media showed that a maximum colour removal of 60% can be achieved. In column studies, complete exhaustion of the media occurred at 180 and 120 bed volumes, respectively, for initial pHs of 3.0 and 6.2. The study thus shows the potential of WTR for primary treatment of real textile dye wastewater.

Drinking water treatment residuals from cyanobacteria bloom-affected areas: Investigation of potential impact on agricultural land application

In cyanobacteria bloom-affected areas, drinking water treatment processes are optimized to ensure the absence of cyanotoxins in their finished water. A concern about the sludge generated from water treatment has emerged because the removed cyanotoxins and cyanobacteria can get concentrated in the sludge, called water treatment residuals (WTR), and these WTR are often applied on land for beneficial purposes. However, the impact of WTR from bloom-affected areas on the agricultural application and public health is hardly reported. The objective of this study was to characterize bloom-affected WTR by focusing on cyanotoxins, toxin-producing cyanobacteria, microbiomes, and resistome profiles. In addition, the fate of WTR-originated microcystin in crops and soil was examined.WTR samples were obtained from a bloom-affected area in Ohio, USA in November 2017. Cyanotoxins and toxin-producing cyanobacteria were quantified with the enzyme-linked immunosorbent assay and droplet digital PCR, respectively. Microbiome and resistome were determined with Nanopore sequencing. Cyanotoxin concentrations were measured: microcystin (259 μg/kg), saxitoxin (0.16 μg/kg), anatoxin-a (not detected), and β-Methylamino-L-alanine (BMAA) (575 μg/kg). MC-producing cyanobacteria concentrations were determined: Planktothrix (5.3 × 107 gene copies/g) and Microcystis (3.3 × 103 gene copies/g). Proteobacteria was the most predominant and Planktothrix phage was a remarkably dominant virus in the WTR microbiome. Aminoglycoside resistance was the most abundant class, and antibiotic resistance was found in multiple pathogens (e.g. Mycobacterium).WTR land application was simulated by growing carrots with a mixture of WTR and soil in a greenhouse. At harvest, ~80% of WTR-originated microcystin was found in the soil (83–96 μg/kg) and 5% accumulated in carrots (19–28 μg/kg). This study provides the first insight into the cyanotoxin, microbiome, and resistome profile of bloom-affected WTR. Our finding suggests that careful WTR management is needed for the beneficial use of WTR for protecting agricultural environments, especially soil and groundwater, and food safety.

Peroxymonosulfate activation by hydroxylamine-drinking water treatment residuals for the degradation of atrazine

Drinking water treatment residuals (WTRs) have been applied in organic pollutants degradation in water by generating reactive oxygen species from peroxymonosulfate (PMS), however, the slow transformation of Fe(III) to Fe(II) may limit its widespread application. Hydroxylamine (HA) was introduced into the system to enhance the degradation efficiency of atrazine (ATZ) and several key reaction parameters (HA concentration, PMS concentration, pH and temperature) were concerned to study their influence on ATZ degradation. The results revealed that ATZ degradation efficiency was enhanced in the HA/WTRs/PMS system. Effects of some basic inorganic ions (Cl−, SO42− and NO3−) and natural organic matter on ATZ degradation were investigated and results showed that both have an inhibitory effect on ATZ removal. In addition to the reduction role, HA can also react directly with PMS to produce free radicals that helpful for ATZ degradation. Sulfate radical and hydroxyl radicals were generated and sulfate radical was identified as primary radicals in the HA/WTRs/PMS system by alcohol quenching experiments. Moreover, the HA/WTRs/PMS system also showed good performance for ATZ degradation in authentic water like surface water and groundwater. Introduction of hydroxylamine into the system may promote organic pollutant degradation and use of WTRs as an iron source for PMS activation provides new ideas for sludge treatment.

Insights into the mechanisms of mercury sorption onto aluminum based drinking water treatment residuals

Several studies have demonstrated the ability of drinking water treatment residuals (WTRs) to efficiently sorb metal cations from aqueous solutions. Reported results have stimulated interest on the potential use of WTRs as sorbent for metal removal from contaminated aqueous effluents as well as in metal immobilization in contaminated soils. However, knowledge on mechanisms of metal sorption by WTRs remains very limited and data on the long-term stability of formed metal–WTR complexes as a function of changing key environmental parameters are lacking. In this study, chemical selective sequential extraction (SSE), scanning electron microscopy combined with X-ray energy dispersive spectrometer (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) were used to gain insight into the different mechanisms of mercury (Hg) binding to aluminum based WTR (Al-WTRs). Results from sorption studies show that a significant portion of Hg becomes incorporated in the operationally defined residual fraction of Al-WTRs, and therefore, not prone to dissolution and mobility. The results of solid phase analyses suggested that Hg immobilization by Al-WTR occurs largely through its binding to oxygen donor atoms of mineral ligands driven by a combination of electrostatic forces and covalent bonding.

A comparison of the phosphorus immobilization capabilities of water treatment residuals before and after settling from lake water

Drinking water treatment residuals (WTRs), which are by-products generated during drinking water treatment processes, could be used to immobilize phosphorus (P) in lake sediments, thereby allowing for control of the internal P loading of a lake. Prior to applying WTRs for this purpose on a large scale, it is necessary to determine the P immobilization capabilities of WTRs under various conditions. This work investigated the P immobilization capabilities of WTRs before and after settling from lake water. The results demonstrated that WTRs have a low risk of leaching metals during settling. The WTRs had a lower P adsorption rate after settling, but their P adsorption capacities differed little under different P concentrations and pH. Moreover, the WTRs had similar capabilities to immobilize P in lake sediments before and after settling. Altogether, these results indicate that the P immobilization capability of WTRs changes little after WTRs settle from lake water. Thus, the use of WTRs to immobilize P in sediments may be a feasible, practical technique for lake restoration.

Nutrient and dissolved organic carbon removal from natural waters using industrial by-products

Attenuation of excess nutrients in wastewater and stormwater is required to safeguard aquatic ecosystems. The use of low-cost, mineral-based industrial by-products with high Ca, Mg, Fe or Al content as a solid phase in constructed wetlands potentially offers a cost-effective wastewater treatment option in areas without centralised water treatment facilities. Our objective was to investigate use of water treatment residuals (WTRs), coal fly ash (CFA), and granular activated carbon (GAC) from biomass combustion in in-situ water treatment schemes to manage dissolved organic carbon (DOC) and nutrients. Both CaO- and CaCO3-based WTRs effectively attenuated inorganic N species but exhibited little capacity for organic N removal. The CaO-based WTR demonstrated effective attenuation of DOC and P in column trials, and a high capacity for P sorption in batch experiments. Granular activated carbon proved effective for DOC and dissolved organic nitrogen (DON) removal in column trials, but was ineffective for P attenuation. Only CFA demonstrated effective removal of a broad suite of inorganic and organic nutrients and DOC; however, Se concentrations in column effluents exceeded Australian and New Zealand water quality guideline values. Water treated by filtering through the CaO-based WTR exhibited nutrient ratios characteristic of potential P-limitation with no potential N- or Si-limitation respective to growth of aquatic biota, indicating that treatment of nutrient-rich water using the CaO-based WTR may result in conditions less favourable for cyanobacterial growth and more favourable for growth of diatoms. Results show that selected industrial by-products may mitigate eutrophication through targeted use in nutrient intervention schemes.

Drinking Water Treatment Residuals: A Review of Recent Uses

Coagulants such as alum [Al2(SO4)3 x 14H2O], FeCl3, or Fe2(SO4)3 are commonly used to remove particulate and dissolved constituents from water supplies in the production of drinking water. The resulting waste product, called water-treatment residuals (WTR), contains precipitated Al and Fe oxyhydroxides, resulting in a strong affinity for anionic species. Recent research has focused on using WTR as cost-effective materials to reduce soluble phosphorus (P) in soils, runoff, and land-applied organic wastes (manures and biosolids). Studies show P adsorption by WTR to be fast and nearly irreversible, suggesting long-term stable immobilization of WTR-bound P. Because excessive WTR application can induce P deficiency in crops, effective application rates and methods remain an area of intense research. Removal of other potential environmental contaminants [ClO4-, Se(+IV and +VI), As(+III and +V), and Hg] by WTR has been documented, suggesting potential use of WTR in environmental remediation. Although the creation of Al plant toxicity and enhanced Al leaching are concerns expressed by researchers, these effects are minimal at circumneutral soil pH conditions. Radioactivity, trace element levels, and enhanced Mn leaching have also been cited as potential problems in WTR usage as a soil supplement. However, these issues can be managed so as not to limit the beneficial use of WTR in controlling off-site P losses to sensitive water bodies or reducing soil-extractable P concentrations.

Use of Drinking Water Treatment Residuals as a Potential Best Management Practice to Reduce Phosphorus Risk Index Scores

The P risk index system has been developed to identify agricultural fields vulnerable to P loss as a step toward protecting surface water. Because of their high Langmuir phosphorus adsorption maxima (P(max)), use of drinking water treatment residuals (WTRs) should be considered as a best management practice (BMP) to lower P risk index scores. This work discusses three WTR application methods that can be used to reduce P risk scores: (i) enhanced buffer strip, (ii) incorporation into a high soil test phosphorus (STP) soil, and (iii) co-blending with manure or biosolids. The relationship between WTR P(max) and reduction in P extractability and runoff P was investigated. In a simulated rainfall experiment, using a buffer strip enhanced with 20 Mg WTR ha(-1), runoff P was reduced by from 66.8 to 86.2% and reductions were related to the WTR P(max). When 25 g kg(-1) WTR was incorporated into a high STP soil of 315 mg kg(-1) determined using Mehlich-3 extraction, 0.01 M calcium chloride-extractable phosphorus (CaCl(2)-P) reductions ranged from 60.9 to 96.0% and were strongly (P < 0.01) related to WTR P(max). At a 100 g kg(-1) WTR addition, Mehlich 3-extractable P reductions ranged from 41.1 to 86.7% and were strongly (P < 0.01) related to WTR P(max). Co-blending WTR at 250 g kg(-1) to manure or biosolids reduced CaCl(2)-P by >75%. The WTR P(max) normalized across WTR application rates (P(max) x WTR application) was significantly related to reductions in CaCl(2)-P or STP. Using WTR as a P risk index modifying factor will promote effective use of WTR as a BMP to reduce P loss from agricultural land.

Use of Water Treatment Residuals to Reduce Soil Phosphorus Loss and Protect Surface Water Quality: an Interregional Study

Use of Water Treatment Residuals to Reduce Soil Phosphorus Loss and Protect Surface Water Quality: an Interregional Study

Beneficial Use of Water Treatment Residuals in Hydroseeding Operations

Beneficial Use of Water Treatment Residuals in Hydroseeding Operations

Evaluating Soil Tests to Predict Bermudagrass Growth in Drinking Water Treatment Residuals with Phosphorus Fertilizer

AbstractDrinking water treatment residuals (WTRs) may serve as a soil substitute to revegetate disturbed land. This study evaluated the use of WTRs as a soil substitute and the ability of soil tests to predict P adequacy. We measured properties and nutrient content of three WTRs (Wister, Mohawk, and ABJ) and a control soil. Bermudagrass [Cynodon dactylon (L.) Pers. var. Greenfield] was grown with four P treatments (0, 50, 100, and 200 mg P kg−1). We measured available P by water, Mehlich 3 (M3P), and Olsen P soil extraction. Mean cumulative bermudagrass yields, across P treatments, were soil (20.6 g), Mohawk (23.6 g) &gt; Wister (9.6 g) &gt; ABJ (1.1 g). Tissue P concentrations were below adequate for WTR and available P in WTR was deficient for Wister and ABJ. Fertilizer P addition did not increase yield or tissue P of bermudagrass grown on WTR. However, bermudagrass grown on soil had increased yield and tissue P with fertilizer addition. The available P measured by soil tests was adequate for Mohawk and inadequate for ABJ, Wister, and soil. Although the M3P and OIsen P soil tests predicted P responses on some WTRs, with fertilizer addition, there was not a yield or tissue response. Water soluble P or Olsen P provide information on the ability of the WTR to support growth but not the ability to predict P adequacy. The M3P soil test overestimated plant availability of P in WTR due to the dissolution of P adsorbed by amorphous Al. Water extracts were the best predictor of P adequacy in WTR and should be used to determine P fertilizer additions to WTR.