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This study investigates the occurrence and characterization of microplastic (MP) in sewage sludge from 3 different cities along the Ganga River, India and their toxic impact while applying sludge for crop production. MP occurred in the ranges of 29.2–60.8 × 103 particles kg−1 with an abundance of 1–5 mm (11.12%), <1 mm–100 μm (32.65%), and 20–100 μm (56.23%) size particles. ATR-FTIR analysis suggested polypropylene, polyethylene, nylon, and polycarbonate as sludge's most common MP polymer. In lab scale trials, sludge MP showed significant toxicity in Vigna radiata and reduced vegetative growth and plant weight was recorded with sludge-inoculated setups. Seedlings with sludge exhibited higher activities of catalase, superoxide dismutase, hydrogen peroxide (H 2 O 2), and malondialdehyde than the control setups. Furthermore, fluorescence microscopy confirmed the MP bioaccumulation in tested seedlings. In summary, our results suggested that wastewater treatment plants (WWTPs) sink large volumes of MP in sewage sludge, which could be hazardous while applying such biosolids for crop production. MP seasonal dynamics in local WWTPs and their role in the mobilization of other toxicant chemicals could be investigated in future studies in this series. [Display omitted] • MP load in sewage sludge ranged between 29.2 and 60.8 × 103 particles/kg. • MP-sized 20–100 μm were higher in sludge. • The plant grown in sludge showed low growth but high oxidative stress. • Fluorescence microscopy confirms the MP accumulation in seedling roots. [ABSTRACT FROM AUTHOR]

The use of sewage sludge in agriculture is known to be environmentally friendly as it is a practical way of recycling municipal waste. A short-term experiment was carried out to study the changes in soil chemical and microbiological properties influenced through the addition of sewage sludge along with saline irrigation under a pearl millet-wheat crop rotation. There were three irrigation (canal water (0.35 dS m-1), 8 and 10 dS m-1 electrical conductivity saline water) and five fertilizer treatments (control-F1, sewage sludge (5 t ha-1)-F2, sewage sludge (5 t ha-1) +50% recommended dose of fertilizer (RDF)-F3, sewage sludge (5 t ha-1)+75% RDF-F4 and RDF-F5). The results showed that soil organic carbon, and available nitrogen, and phosphorus were reduced significantly under saline conditions but there was an increase in available potassium with the increasing salinity levels of the irrigation water. A significant reduction in soil microbial biomass carbon and enzyme activities was caused by 8 and 10 dS m-1 as compared to 0.35 dS m-1 at different growth stages of crops. Treatment F4 attained the highest soil microbial activity at each crop growth stage by a significant margin among all of the fertilizer treatments, which is associated with a substantial build-up of organic carbon and available NPK in the soil. Soil microbial activities followed a particular trend: at 35 and 75 days after sowing>harvest>sowing in pearl millet and wheat, respectively. Sewage sludge dumping is a major problem in India, and the present study suggests that by applying sewage sludge, soil biological health is improved; therefore its use in agriculture is recommended to farmers. [ABSTRACT FROM AUTHOR]

Field experiments were conducted for 2 years in sandy loam soil, to study the direct effect of organic manures i.e. sewage sludge (SS), vermicompost (VC) and sesbania (SB) and chemical fertilizers on rice (Oryza sativa) and their residual effect on wheat (Triticum aestivum) grown in sequence in winter (Rabi) and summer (Kharif) season during 2015–2016 to 2016–2017 at Varanasi, Uttar Pradesh. Residual effect of organic sources of nutrients as SS, VC and SB were monitored up to fourth crop (II wheat) in sequence applied in conjunction with 75% recommended dose of fertilize (RDF). Among the nutrient sources, the maximum grain yield in I rice (4.89 t ha−1), II rice (4.95 t ha−1), was recorded in treatment T3 (100% RDF with S, Zn, B) whereas in I wheat (4.68 t ha−1) and II wheat (4.59 t ha−1), it was recorded in T4 (customized fertilizer). The maximum straw yield during all four crops was recorded in T3 (100% RDF with S, Zn, B) in rice and T4 (customized fertilizer) in wheat crop, which showed 25, 32, 23 and 28% increase over 100% RDF (T2). Application of 100% RDF along with S, Zn, B and customized fertilizer increased the total uptake of N, P, K, S and B and also in net returns and B:C ratio followed by organic treatments. [ABSTRACT FROM AUTHOR]

Sewage treatment plants (STPs) as a carrier of microplastics (MPs) have received considerable attention worldwide recently. In India, the majority of studies on MPs have been conducted in sediments, riverine, and marine systems, while knowledge on MPs occurrence in STPs is scarce. Henceforth, this work evaluated the presence of MPs in sewage and sludge in a hybrid growth, secondary treatment-based STP system. Optical microscopy, scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy methods were used to examine the abundance of MPs in raw sewage, effluent from different treatment units of the STP, and sludge samples. A total number of MPs of 201 ± 19 (2021) and 197 ± 22 (2022) were detected in the studied STP system. Results showed that MPs ranged between 64.3 ± 4.89–47.66 ± 4.71 n/L (sewage) and 1.14 ± 0.30–1.38 ± 0.65 n/g (sludge) with the overall removal efficacy of the studied STP estimated to be around 80%. Fragments and fibers were predominant among all shapes and particles mostly belonged to sizes <50 μm and <50 μm–250 μm in sewage and sludge, respectively. In total, seven polymers were identified of which low-density polyethylene (LDPE) constituted the highest proportion in sewage (26%–31%) and polyvinyl chloride (PVC) contributed the highest in the sludge (22%–27%). Moreover, MPs control measures have been discussed based on the findings of this study to restrict MPs re-entry into the environment via treated effluent and sludge. [Display omitted] • First study on MPs occurrence and removal in a hybrid growth MBBR-based STP. • Around 80% MPs were removed via the primary and secondary treatment stages in the STP. • LDPE (in sewage) and PVC (in sludge) were the most prevalent polymers. • Small-sized MPs (<250 μm) like fragments and fibers were predominant shapes. • Advanced treatment options for MPs removal from secondary-treated effluent discussed. [ABSTRACT FROM AUTHOR]

In this article the authors document evolving attitudes, policies and roles of stakeholders in wastewater and faecal-sludge management in India, China and Ghana. In each country there is momentum for expanding not just access to sanitation at the household/community levels, but also for greater treatment and safe end-of-life management of human excreta. Governments are increasingly looking to engage the private sector, but models of engagement that make a compelling business case and instil confidence in cost recovery will have to emerge before the private sector takes an active role in wastewater and faecal sludge treatment in low-income countries. [ABSTRACT FROM AUTHOR]

The Narmada Gelatin produces Lime sludge during its manufacturing operations located at Jabalpur in Madhya Pradesh. Narmada Gelatin is being disposed their wastes through environmentally sound technologies. ACC has being co-processed lime sludge waste through co-processing in their kiln at Kymore. Toward this objective, both ACC and Narmada Gelatin have worked together in the past few months to evaluate the feasibility of co-processing the waste in the kiln at ACC Kymore Works. Earliar it was difficult to dispose of lime sludge for the industry. The quantity of lime sludge is being generated 300 ton per month from the process of deliming it is the process where lime get used for ossein maturation for 40 to 65 days. The huge quantity generation of lime sludge was disposing in open areas or low laying areas. That was being created surface and under ground water pollution. ACC has analyzed the lime sludge sample and has being at Kymore works. The cement process perforce requires high temperature in the kiln around 1400-1450 oC with a high residence time of 4-5 see such high temperature conditions ensure that no noxious emission take place during the co-processing of the waste materials. [ABSTRACT FROM AUTHOR]

The growing demand for food in India, due to rising population and rapid industrialization, necessitates judicious and sustainable management of soil and water resources. While the increase in agronomic production of irrigated rice-wheat system (RWS) has been impressive since the 1970s, the low water- and fertilizer-use efficiency has caused degradation of soil quality and pollution of surface and ground waters. With increasing competition for soil and water for non-agricultural uses (e.g., urbanization, industrial use), the strategy is to increase production per unit input of scarce resources through agricultural intensification, and by reducing losses and optimizing the input-use efficiency. Strategies of soil-water management in India's dry farming regions include conserving water in the root zone, water harvesting, and recycling, and integrated nutrient management (INM) involving use of crop residue mulch and biosolids. Similarly, soil-water management in India's irrigated regions (e.g., RWS in the Indo-Gangetic Basin) include INM, crop-residue management, efficient irrigation methods (furrow, drip), irrigation with saline water, alternative cropping systems, and no-till farming. Soil water, the precious and scarce resource, must be used prudently. Undervaluing a scarce resource can lead to its misuse, overexploitation, depletion, pollution, and contamination and eutrophication. [ABSTRACT FROM AUTHOR]

Arsenic in groundwater is a huge problem in numerous regions of the world. Many people are exposed to high arsenic concentrations and consequently risk getting ill or even die as a result of arsenic poisoning. There are several efficient technologies for the removal of arsenic but often these methods have disadvantages, e.g. high costs for installation and/or operation, the need for chemicals or the production of arsenic contaminated filter sludge. These disadvantages can make the application difficult, especially in poor regions. Under suitable ancillary conditions the subterranean (in-situ) treatment, which is often used for iron and manganese removal from groundwater, can also be applied for the removal of arsenic and can be a cost-effective treatment technology. A field trial was carried out with a low-cost in-situ treatment plant in West Bengal/India which is described in this paper, in order to investigate whether this treatment technology is also applicable under the boundary conditions there. As for the in-situ treatment technology besides oxygen no additives are required and no arsenic contaminated filter sludge is produced this technology could be a suitable method for arsenic removal especially in poor regions. [ABSTRACT FROM AUTHOR]

Flue gas desulfurization-derived wastewater sludge (FGD-WWS) has been produced increasingly in China and India etc., and its content of heavy metals (HMs) including Cd, Cr, Cu, Hg, Ni and Zn seriously exceeds the limits allowed. Developing the suitable disposal of FGD-WWS is therefore significantly important and necessary. The novel process of electrokinetic treatment combined with chemical pretreatment of HMs in FGD-WWS were proposed here to improve the removal efficiency. Results indicate that the effects of different pretreatment agents (citric acid (CA), ammonia, tetrasodium of N, N-bis (carboxymethyl) glutamic acid (GLDA), and rhamnolipid) on the ET of HMs were different. To investigate the mechanism of combined process, the transformation potential (TP), exchange potential (EP) and removal potential (RP) were calculated. Correlation analysis shows the correlation between TP and RP was higher than that between EP and RP, indicating that the removal efficiency is mainly affected by the fraction transformation of HMs. Electric field, pH and pretreatment agents are main factors causing fraction transformation and affecting TP. Focusing on fraction transformation is an efficient way to improve further the removal efficiency. The work is promisingly valuable for developing the technology of treating FGD-WWS. [Display omitted] • The electrokinetic treatment and chemical pretreatment improve removal efficiency. • Chemical pretreatment with different agent has totally different effect. • The removal efficiency is mainly affected by the fraction transformation. • Adding different pretreating agents facilitate the fraction transformation. [ABSTRACT FROM AUTHOR]

Abstract: In India, over the last few decades, there has been a remarkable increase in sewage sludge production due to population increase and unplanned urbanization. The aim of the present study was to investigate the ability of an epigeic earthworm Eisenia foetida to transform primary sewage sludge (PSS) amended with cow dung (CD) into value added product, i.e., vermicompost in laboratory scale experiments. Two approaches investigated in the study were: (1) evaluation of vermistabilization of PSS and CD mixtures after 15 weeks in terms of fertilizer quality of the products and; (2) growth and reproduction of Eisenia foetida up to 11 weeks in different vermireactors. In all the PSS and CD mixtures, a decrease in pH, TOC and C:N ratio, but increase in EC, TKN, TK and TP was recorded. The heavy metals’ content in the vermicomposts was higher than initial mixtures. Maximum worm biomass was attained in 10% PSS+90% CD mixture while, the worm growth rate was highest in 30% PSS+70% CD feed mixture. It was inferred from the study that addition of 30–40% of PSS with CD had no adverse effect on the fertilizer value of the vermicompost as well as growth of Eisenia foetida. The results indicated that PSS could be converted into good quality manure by vermicomposting if mixed in appropriate ratio (30–40%) with cow dung. [Copyright &y& Elsevier]

The effects of sulfur concentration, initial pH of the sludge and sludge solid content on metal bioleaching were examined using anaerobically digested sewage sludge procured from a typical sewage treatment plant in Delhi, the capital city of India. Experiments on effect of sulfur concentration were carried out using 0-4 g L-1 of elemental sulfur to optimize the concentration of elemental sulfur for efficient bioleaching. For the type of sludge (20 g L-1 solid content) used in the present study, 2 g L-1 of elemental sulfur was found sufficient in metal bioleaching in the following order: Zn 86%, Cu 71.5%, Mn 70%, Ni 58.3% and Cr 43.8%. Changes in pH, sulfate concentration and oxidation-reduction potential (ORP) as a function of time were experimentally monitored. A rapid change in the above parameters took place in 4-6 days followed by a slow change until the 10th day. The change in pH with time was observed to vary at different initial pH values (pH 7 to pH 3) of the sludge; however, there was not much difference in the final pH achieved and final metal solubilization which ranged from: Cu 83.6-94.2%, Ni 27.7-29.8%, Zn 89-94.8%, Mn 67.5-79% and Cr 34.1-44.1% The results of the present studies strongly indicate that using 2 g L-1 elemental sulfur, indigenous sulfur oxidizing microorganisms can bring down pH to a value needed for significant metal solubilization. Also, bioleaching can be carried out successfully over a wide range of initial pH values of the sludge. Further, at higher sludge solid concentration than 20 g L-1, lower metal solubilization was achieved due to the buffering capacity of the sludge. [ABSTRACT FROM AUTHOR]

This paper presents results of a novel application of coupling the Activated Sludge Model No. 3 (ASM3) and the Anaerobic Digestion Model No.1 (ADM1) to assess a tropical wastewater treatment plant in a developing country (Surat, India). In general, the coupled model was very capable of predicting current plant operation. The model proved to be a useful tool in investigating various scenarios for optimising treatment performance under present conditions and examination of upgrade options to meet stricter and upcoming effluent discharge criteria regarding N removal. It appears that use of plant-wide modelling of wastewater treatment plants is a promising approach towards addressing often complex interactions within the plant itself. It can also create an enabling environment for the implementations of the novel side processes for treatment of nutrient-rich, side-streams (reject water) from sludge treatment. [ABSTRACT FROM AUTHOR]

Abstract: Use of sewage sludge, a biological residue produced from sewage treatment processes in agriculture is an alternative disposal technique of waste. To study the usefulness of sewage sludge amendment for palak (Beta vulgaris var. Allgreen H-1), a leafy vegetable and consequent heavy metal contamination, a pot experiment was conducted by mixing sewage sludge at 20% and 40% (w/w) amendment ratios to the agricultural soil. Soil pH decreased whereas electrical conductance, organic carbon, total N, available P and exchangeable Na, K and Ca increased in soil amended with sewage sludge in comparison to unamended soil. Sewage sludge amendment led to significant increase in Pb, Cr, Cd, Cu, Zn and Ni concentrations of soil. Cd concentration in soil was found above the Indian permissible limit in soil at both the amendment ratios. The increased concentration of heavy metals in soil due to sewage sludge amendment led to increases in heavy metal uptake and shoot and root concentrations of Ni, Cd, Cu, Cr, Pb and Zn in plants as compared to those grown on unamended soil. Accumulation was more in roots than shoots for most of the heavy metals. Concentrations of Cd, Ni and Zn were more than the permissible limits of Indian standard in the edible portion of palak grown on different sewage sludge amendments ratios. Sewage sludge amendment in soil decreased root length, leaf area and root biomass of palak at both the amendment ratios, whereas shoot biomass and yield decreased significantly at 40% sludge amendment. Rate of photosynthesis, stomatal conductance and chlorophyll content decreased whereas lipid peroxidation, peroxidase activity and protein and proline contents, increased in plants grown in sewage sludge-amended soil as compared to those grown in unamended soil. The study clearly shows that increase in heavy metal concentration in foliage of plants grown in sewage sludge-amended soil caused unfavorable changes in physiological and biochemical characteristics of plants leading to reductions in morphological characteristics, biomass accumulation and yield. The study concludes that sewage sludge amendment in soil for growing palak may not be a good option due to risk of contamination of Cd, Ni and Zn and also due to lowering of yield at higher mixing ratio. [Copyright &y& Elsevier]

Sewage sludge, generated post wastewater treatment, constitutes only a small percentage of the total amount of sewage treated, however, its sustainable management is inevitable. In this study, the energy recovery potential of sewage sludge by incineration and anaerobic digestion is investigated for India. The dewatered sludge has total solid content of 25–45% whereas, the primary characteristics of sewage sludge showed significant organic content of about ∼23–40% (dry basis). The calorific value was found to be 8–21 MJ/kg for sludge dry matter. The energy recovery potential of sewage sludge was 555–1068 kWh/tonne on sludge dry matter basis for incineration and 315–608 kWh/tonne for anaerobic digestion. Additionally, the energy recovery potential of current sewage treatment in India was found to be ∼15.3 × 105 or 8.6 × 105 MWh, annually for incineration and anaerobic digestion, respectively. The study had provided in depth view of sludge to be considered as energetic material and its energy recovery potential countrywide, which would not only help for give a proper direction for recovering energy but also helpful to deal with the issue of sludge management in India. Image 1 • Sludge generated from sewage treatment plants was explored for energy alternatives. • The sewage sludge contains high heating value, organic matter and volatile matter etc. • Energy recovery potential of sewage sludge produced in India was estimated. • The energy recovery from sewage sludge could reduce energy demands and reduce land requirement for its disposal as well. [ABSTRACT FROM AUTHOR]

Sewage sludge (SS) management has been regarded as a serious environmental and health issue around the globe, especially in developing countries like India, mainly due to the lack of proper regulatory criteria, and appropriate engineering infrastructures. The present research work demonstrates the utilization of Fly Ash (FA) in varying percentages (with an interval of 10%) with SS as brick for sustainable building material with special emphasis on dimensional Effect. The impact of dimensional effect is measured using compressive strength behaviour for a stress rate of 14 MPa/min of two different sizes of brick i.e. D1 and D2 of sizes 7 × 7x7 cm3 and 2 × 2x2 cm3, respectively. Owing to the sintering effect, the maximum strengths of 4.02 MPa and 7.6 MPa are noticed for a composition of 60% SS+40% FA for D1 and 40% SS + 60% FA for D2, respectively. According to the Indian Standards (IS) 13757: 1993, an exhibited strength of more than 3.5 MPa by any brick composition enables it to be used as a common building brick. In general, due to the formation of triangular wedges, the D2 bricks exhibited better strength for any mixing ratio of FA and SS. The added benefit in our study was lower thermal conductivity (0.48 Wm−1K−1) of the prepared fired brick implying its better insulation property. Our study uniquely highlights the possible utilization of FA for stabilizing SS for sustainable substitution of natural clay fired brick. Future study may further investigate the compositional effect of FA on the thermal and thermodynamic attributes of the bricks. Image 1 • Pioneer study on bricks that visualizes dimensional effect along with mechanical properties. • 40–60% fly ash with sewage sludge satisfies Indian codal provisions as construction material. • Thermal conductivity of synthesized brick is lower than conventional fired clay bricks. • Dimensional effect significantly influences the compressive strength behaviour. [ABSTRACT FROM AUTHOR]

Abstract: Sludge Hygienisation Research Irradiator (SHRI) Facility at Vadodara (India) has been disinfecting liquid sewage sludge with 60Co gamma rays since 1992. At some point, the radiation process was modified from its originally designed closed-loop system to an open-loop system. Dosimetry experiments were performed to estimate absorbed doses to the sludge for different periods of irradiation of a 15m3 batch in an open-loop irradiation process. The paper reports the dosimetry results and evaluated operational parameters of the irradiator, namely, effective dose rate in the open-loop system, irradiation efficiency, and throughput. Also, the open-loop system and the closed-loop system are compared in terms of the effective dose rate. [ABSTRACT FROM AUTHOR]

The article presents a study on the use of lime sludge waste from the paper industry. It adopts the situation at the Nagaon Paper Mill, a public sector pulp and paper mill which is a unit of the Hindustan Paper Corporation Ltd. in Assam, India wherein it generates 448 tonnes of lime sludge per day as solid waste. It notes that Assam's agricultural soil is acidic and that liming is important to maintain the potential hydrogen of the soil through lime sludge waste instead of marketed lime.

• Biochar was an optimal carrier for Cajanus cajan inoculants based on Bradyrhizobium strains. • Neither the carrier nor the bradyrhizobia strain influenced the nodule occupancy. • Nodule occupancy by the inoculated strain depended solely on the level of resident nodulating bacteria. • Inoculation was effective for agroecosystems in soils with 103 or less resident nodulating bacteria per g soil. Pigeonpea (Cajanus cajan) originated in India and is now a major source of protein in countries in tropical and subtropical regions worldwide. However, little is known about the effect on crop yields of inoculation with appropriate rhizobia strains. The objective of this study was to explore the possibility of improving pigeonpea yields in the Caribbean region, by inoculating with selected N-fixing symbionts. To achieve the study objective, we selected three elite strains of the genus Bradyrhizobium isolated from root nodules of pigeonpea in the Dominican Republic, we formulated them using innovative carriers, and finally we tested the formulated inoculant on eight farms located in the Dominican Republic. Three different carriers (sewage sludge, pine bark biochar and poultry litter) plus perlite as control were tested for the formulation. The first step was to test bacterial survival in the different carriers at different times up to one year (shelf-life). Pine bark biochar and the control resulted in the best shelf-life and were selected for the field experiment. The experimental design comprised two pigeonpea cultivars and five fertilisation strategies: Inoculation with three Bradyrhizobium strains without nitrogen (N) fertilisation, plus two non-inoculated controls one of them fertilised with 125 and 210 kg N ha−1 in non-irrigated and irrigated fields respectively. Nodule occupancy by the inoculated bacterial strain depended solely on the level of soil native nodulating bacteria and not on the bacterial strain or the carrier. Inoculation produced, on average, a significant yield increase compared to the non-inoculated non -N- fertilised control. Furthermore, the yield with the inoculated treatments did not significantly differ from the yield of the N-fertilised control. However, either inoculation or N-fertilisation were ineffective in two out of the eight fields with more than 104 nodulating bacteria g soil−1, compared to the non-inoculated non-N-fertilised control. Yield was neither significantly affected by the bacterial strain nor by the cultivar-strain interaction, and therefore, the two cultivars can be considered promiscuous. Neither carrier had a significant effect on yield. Thus, inoculants based on strains of Bradyrhizobia isolated from the root nodules of pigeonpea, formulated with pine bark biochar or perlite as carrier, are recommended as a good strategy to ensure food security in tropical agroecosystems with pigeonpea. [ABSTRACT FROM AUTHOR]

The notion of the infrastructure gap is widely articulated in development studies to denote lacunae and areas of need in infrastructure functioning and connectivity across regions and nations. Sanitation infrastructure is one of the clearest areas in which to examine this gap. To close the gap, government and multilateral agencies are espousing citywide inclusive sanitation. This means comprehensive sanitation services for all through a combination of centralized and decentralized projects and a variety of techniques and services. However, this diversity of projects, techniques, and services will create additional challenges for infrastructure connectivity and functionality that need to be addressed through empirical research. We explore the gaps in wastewater and fecal sludge management infrastructure in India by approaching the problem from the activities and perspectives of three nonstate leaders and their associates. We argue that the notion of infrastructure disarray is an appropriate orienting idea as it points to an emerging field of experimentation and innovative activity while also showing how conditions of dysfunction and disconnection are sustained and reproduced. Taking disarray as a condition of infrastructure confusion among overlapping and disconnected segments of the sewage services chain, the cases show how nonstate actors and their communities are confronting disarray, reproducing these conditions of disarray, or grappling with ways to overcome this disarray. This article is categorized under:Engineering Water > Sustainable Engineering of WaterEngineering Water > Planning WaterHuman Water > Water Governance The Nagwa drain in Varanasi where Dr. Mishra carried out his flow measurements.This paper argues that infrastructure disarray rather than infrastructure gap is a more useful notion for framing the challenges and conditions of wastewater management in India today. Taking disarray as a condition of infrastructure confusion among overlapping and disconnected segments of the sewage services chain, the cases show how nonstate actors and their communities are confronting disarray, reproducing these conditions of disarray, or grappling with ways to overcome this disarray. [ABSTRACT FROM AUTHOR]