Industrial Wastewater Treatment Facilities Research Articles

Analysis on Operation and Water Quality Characteristics of Centralized Wastewater Treatment Plants of Industrial Parks in Yellow River Basin, China

The Yellow River basin serves as an important economic belt and industrial base in China, featuring numerous industrial parks. However, alongside its economic significance, the basin struggles with significant water environmental challenges. This study analyzed the operational status, influent water quality, and energy consumption of 63 centralized wastewater treatment plants (WWTPs) from 54 major industrial parks in the Yellow River basin. The scale of these WWTPs was primarily within the range of 1 × 104~5 × 104 m3/d, with an average hydraulic loading rate of 53.8%. Aerobic treatment processes are predominant. The influent concentrations of chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammonia nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP) in the WWTPs exhibited a right-skewed distribution. The BOD/COD ratio of the WWTPs fluctuated between 0.1 and 1.6, and 75% of the WWTPs showed a COD/TN ratio lower than eight. The average BOD5/TN was 2.7, and the probability of influent BOD5/TP > 20 was 84.6%. A significant linear correlation exists between the influent BOD and COD concentrations, while moderate linear relationships are also observed among NH3-N, TN and TP, emphasizing the importance of maintaining appropriate nitrogen and phosphorus levels for efficient pollutant removal. The average electricity consumption of WWTPs in the Yellow River basin in 2023 was 1.1 kWh/m3. It is important to upgrade these WWTPs and reduce their energy consumption. Further strengthening the construction of industrial wastewater collection and treatment facilities based on regional characteristics is recommended to promote the high-quality development of industrial wastewater treatment in the Yellow River basin.

Optimizing Height Above Nearest Drainage parameters to enable rapid flood mapping in North Carolina

Surface water flooding represents a significant hazard for many infrastructure systems. For example, residential, commercial, and industrial properties, water and wastewater treatment facilities, private drinking water wells, stormwater systems, or transportation networks are often impacted (i.e., in terms of damage or functionality) by flooding events. For large scale events, knowing where to prioritize recovery resources can be challenging. To help communities throughout North Carolina manage flood disaster responses, near real-time state-wide rapid flood mapping methods are needed. In this study, Height Above Nearest Drainage (HAND) concepts are combined with National Water Model river discharges to enable rapid flood mapping throughout North Carolina. The modeling system is calibrated using USGS stage-discharge relationships and FEMA 100-year flood maps. The calibration process ultimately provides spatially distributed channel roughness values to best match the available datasets. Results show that the flood mapping system, when calibrated, provides reasonable estimates of both river stage (or corresponding water surface elevations) and surface water extents. Comparing HAND to FEMA hazard maps both in Wake County and state-wide shows an agreement of 80.1% and 76.3%, respectively. For the non-agreement locations, flood extents tend to be overestimated as compared to underestimated, which is preferred in the context of identifying potentially impacted infrastructure systems. Future research will focus on developing transfer relationships to estimate channel roughness values for locations that lack the data needed for calibration.

Assessing industrial wastewater effluent toxicity using boosting algorithms in machine learning: A case study on ecotoxicity prediction and control strategy development

Trace heavy metals have a tendency to persist in the effluent of industrial wastewater treatment facilities, leading to toxic effects on downstream water bodies. Traditional assessment methods relied on animal testing, but ethical concerns have rendered them unacceptable. An alternative solution is to evaluate wastewater toxicity using trophic-level aquatic organisms as bioassays. However, these bioassay methods involve costly and time-consuming chemical and biological analytical experiments. In this study, an artificial intelligence-powered water quality assessment (AiWA) approach is proposed for predicting industrial effluent ecotoxicity to further enhance the quick and cost-effective ecotoxicity assessment process. Initially, 99 samples were collected from industrial wastewater treatment plants representing 21 different industries in the Republic of Korea. Fourteen parameters were measured, encompassing both physicochemical and ecotoxicological aspects. Boosting algorithms, especially extreme gradient boosting (XGBoost) and adaptive boosting (AdaBoost), were employed for model development. XGBoost outperformed AdaBoost in terms of model performance. Feature selection analysis revealed that conductivity, copper, lead, selenium, pH, and zinc concentrations were the most suitable inputs for training the boosting model. The innovated XGBoost-based AiWA model demonstrated significantly higher performance (i.e., up to 80%) compared to conventional models with an R2 value of exceeding 0.94 and root mean square error of 3.5 toxicity unit for predicting the integrated toxicity unit (ITU). Additionally, pH and conductivity emerged as crucial indicators for reflecting ecotoxicity levels. Specially, this case study indicated that non-toxic/directly dischargeable levels (TU ≤ 1) were achieved when the pH ranged from 6.8 to 8.4 and the conductivity remained below 1651 μS/cm. These findings are expected to facilitate rapid and cost-effective detection of heavy metal ecotoxicity in industrial wastewater effluents, aiding decision-making in wastewater management.

Fabrication, Modification, and Mechanism of Nanofiltration Membranes for the Removal of Heavy Metal Ions from Wastewater

AbstractHeavy metals present in wastewater and water scarcity are a global challenge worldwide. The elimination of heavy metals in wastewater is necessary to protect the ecosystem and human health. Heavy metals such as lead, cadmium, and mercury are among many other toxic heavy metals present in wastewater. There are several conventional methods that have been implemented to mitigate heavy metal pollution in wastewater and according to literature, it has been evident that the nanofiltration (NF) separation technique requires minimal pressure to obtain high rejections of multivalent inorganic salts compared to conventional methods. NF separation process is highly competitive in terms of selectivity and cost‐benefit. The growing research trend of NF fabrication and modification collates that the technology has been applied in various industrial and municipality wastewater treatment facilities. The review paper aims to illustrate the health impacts of heavy metal exposure, the cons of conventional methods and the utilization of NF membranes in wastewater treatment, the overall factors affecting membrane performance, and future aspects of the separation techniques.

Characteristics of TOC Treatment for Industrial Wastewater Treatment -Characteristics of Industrial Wastewater TOC Treatment Status and TOC Treatment by Ozone and Advanced Oxidation Process-

Objectives:As the organic pollutant indicator is changed from COD<sub>Mn</sub> to TOC and the demand for TOC treatment of industrial wastewater increasing, the current situation of TOC treatment of wastewater discharge facilities of each industrial category is analyzed, and it is intended to consider the possibility of residual TOC treatment by ozone and advanced oxidation process.Methods:To review the TOC treatment situations of wastewater discharge facilities of each industrial category, the field survey data (46 sites) by Environment Ministry and Korea Environment Corporation were analyzed according to inflow TOC concentrations, direct/indirect discharge type, and main treatment process of wastewater treatment facilities. To review the characteristics of TOC treatment by ozone and advanced oxidation processes, previous studies and the results of field pilot tests conducted by ozone companies were comprehensively analyzed.Results and Discussion:The TOC treatment level varies depending on the inflow TOC concentrations to each industrial wastewater treatment facility, direct/indirect discharge type depending on the location of the wastewater treatment facilities, and the main treatment process of the wastewater treatment facility. In particular, the TOC removal rate differed by more than 20% depending on the presence or absence of biological treatment. The wastewater treatment facilities that require additional treatment of residual TOC were divided as follows (1) when the facility has biological treatment as main process, increasing unexpected inflow TOC load in treatment facilities or the condition of the biological treatment become worsen. (2) when the facility has phy-chemical treatment as main process, increasing unexpected inflow TOC load. (3) extending the replacement cycle of activated carbon to save maintenance cost. The advance oxidation process decomposes easily by OH radicals through the radical substitution of unsaturated hydrocarbons and aromatic compounds, so the removal rate of TOC by the O<sub>3</sub>+H<sub>2</sub>O<sub>2</sub> advanced oxidation pilot test was 14.7~93.5%, higher than that of ozone oxidation. The specific ozone consumption per TOC removal amount (O<sub>3</sub>/ΔTOC) by O<sub>3</sub>+H<sub>2</sub>O<sub>2</sub> advanced oxidation is 8.5~22.5mgO<sub>3</sub>/mgTOC, which is 1/5 of that of ozone oxidation only. In addition, comparing ozone demand by COD<sub>Mn</sub> and TOC removal, ozone demand of O<sub>3</sub>+H<sub>2</sub>O<sub>2</sub> advanced oxidation to remove TOC is 2.7 to 4.3 times compared to that by O<sub>3</sub> oxidation to remove COD<sub>Mn</sub>.Conclusion:In order to reduce residual TOC from industrial wastewater effluent, it is necessary to secure stability of the existing main treatment process in preparation for load fluctuations, and the technologies research on complex advanced oxidation processes, hybrid advanced oxidation processes, and pretreatment technology to reduce ozone demand is needed for economical field application.

Hydraulic Simulation of Local Industrial Wastewater Treatment Facilities

The creation of technologies and equipment for wastewater treatment remains a topical issue for the efficient use of water resources and ensuring environmental sustainability. The article presents the results of research on improving the efficiency of vertical sewer settling tanks for the treatment of urban and industrial wastewater based on hydraulic calculations. The study used hydraulic modeling methods. A laboratory model of vertical settling tanks has been developed. The studies were carried out using real industrial wastewater. The process of achieving a reduction in the amount of suspended solids in industrial and storm drains to 345 mg/l, the amount of oil products to 3-3.5 mg/l in a vertical sump and ways to implement it in nature has been studied and shown.

Eco-efficiency evaluation of Chinese provincial industrial system: A dynamic hybrid two-stage DEA approach.

In China, industrial pollution has become an urgent problem for policy makers and enterprise managers. To better support industrial development, we need to determine the effectiveness of policies through efficiency evaluation. China’s provincial industrial system consists of two stages: production and emission reduction. The emission reduction stage is composed of three parallel sub stages: solid waste treatment, waste gas treatment and wastewater treatment. In this process, the treatment capacity of industrial wastewater treatment facilities can be used as carry forward variable, which is not only the desirable output of the previous emission reduction stage, but also the input of the current emission reduction stage. Therefore, this paper proposes a dynamic hybrid two-stage data envelopment analysis (DEA) model for eco-efficiency evaluation of industrial systems, and applies it to a case study of Chinese regional industry. Applying the data collected from 2011 to 2015 to the model, the following conclusions can be drawn: (1) During the whole survey period, the average eco-efficiency was 0.9027. The overall eco-inefficiency of China’s provincial industrial system during the study period is mainly due to low efficiency of solid waste treatment and waste gas treatment. (2) The average eco-efficiency of provincial industrial system increased steadily from 2011 (0.6448) to 2014 (0.6777), but decreased slightly in 2015 (0.5908). (3) The carry forward treatment capacity of industrial wastewater treatment facilities has a remarkable impact on provincial industrial system efficiency scores, especially at the wastewater treatment stage (0.6002 vs 0.3691). (4) Provincial industrial system exists distinct geographical characteristics of low efficiency. This study has important guiding significance for policy makers and enterprise managers who are concerned about industrial pollution control.

The Fate and Transport of Chlorinated Polyfluorinated Ether Sulfonates and Other PFAS through Industrial Wastewater Treatment Facilities in China.

Wastewater from certain industrial processes can be primary emission sources of per- and polyfluoroalkyl substances (PFAS) and fluorinated alternatives like chlorinated polyfluorinated ether sulfonates (Cl-PFESA). Two such industrial processes are electroplating and textile printing and dyeing (PD). This study focused on the fate of Cl-PFESA in wastewater from these two industrial processes, in comparison to other PFAS, as they went through different wastewater treatment plants located in southeast China. The total target PFAS concentrations were 520 ± 30 and 4200 ± 270 ng/L at the effluents of the PD WWTP and electroplating WWTP, respectively. Specifically, 6:2 Cl-PFESA (18%) and 8:2 Cl-PFESA (0.7%) were abundant in electroplating-wastewater. Cl-PFESA were also detected in PD wastewater but at trace concentrations and were likely present due to diffuse emissions. The dissolved-phase Cl-PFESA and PFAS mass flows through the WWTPs were fairly constant throughout both facilities. The majority of Cl-PFESA was captured by sludge sedimentation. However, there were individual treatment processes that could cause the wastewater concentrations to fluctuate, and also could lead to relative enrichment of specific Cl-PFESAs as indicated by the 6:2/8:2 Cl-PFESA ratios. Cl-PFESA and perfluoroalkyl sulfonic acids were more influenced by the investigated treatment processes than perfluorocarboxylic acids.

Deployment and Optimisation of a Pilot-Scale IASBR System for Treatment of Dairy Processing Wastewater

Increased pressure is being applied to industrial wastewater treatment facilities to adhere to more stringent regulations for the discharge of treated wastewater and to improve energy efficiency of the process. Nitrogen and phosphorous removal can be challenging to achieve efficiently, and in the case of phosphorous removal, can often necessitate the use of chemicals. There is a major drive globally to improve wastewater treatment infrastructure, whilst simultaneously reducing the carbon footprint of the process. The intermittently aerated sequencing batch reactor offers a modification of the well-known sequencing batch reactor process that can enable lower energy requirements than conventional sequencing batch reactor processes and can facilitate enhanced nutrient removal capacities. However, to date much of the previous literature has focused on relatively short laboratory-scale trials (often with synthetic wastewater) which may not be representative of larger scale system performance. This study explored the intermittently aerated sequencing batch reactor technology via a case-study deployment at a dairy production facility, in terms of treatment efficiency and energy efficiency with a focus on optimisation between phases. High treatment capacity and operational flexibility was achieved with NH4-N removals averaging >89%, PO4-P removal averaging >90% and total suspended solids removal averaging >97%. This research demonstrates the characteristics of intermittently aerated sequencing batch reactor technology at scale to effectively achieve biological nutrient removal. In addition, this study demonstrated that when effectively managed, energy savings and reductions in carbon emissions in the region of 36–68% are achievable through optimisation of reactor operation.

Molecular biomarker responses in the freshwater mussel Anodonta anatina exposed to an industrial wastewater effluent

Using a selection of molecular biomarkers, we evaluated responses in freshwater mussels (Anodonta anatina) exposed to effluent from an industrial wastewater treatment facility. The aims of this work were to (1) assess biomarkers of general toxicity under sublethal exposure to an anthropogenic mixture of chemicals, represented by an arbitrary effluent, and (2) evaluate the potential of A. anatina as a bioindicator of pollution. Adult mussels (n = in total 32; 24 males and 8 females) were exposed (96 h) in the laboratory to a fixed dilution of effluent or to a control treatment of standardized freshwater. Metal concentrations were in general higher in the effluent, by an order of magnitude or more, compared to the control. Toxic unit estimates were used as proxies of chemical stress, and Cu, Ni, and Zn were identified as potential major contributors (Cu> Ni > Zn). Six transcriptional (cat, gst, hsp70, hsp90, mt, sod) and two biochemical (AChE, GST) biomarkers were analyzed in two tissues, gills, and digestive glands. Out of the 16 responses (eight biomarkers × two tissues), 14 effect sizes were small (within ± 28 % of control) and differences non-significant (p > 0.05). Results did however show that (1) AChE activity increased by 40% in gills of exposed mussels compared to control, (2) hsp90 expression was 100% higher in exposed female gills compared to control, and (3) three marker signals (AChE in both tissues, and hsp70 in gills) differed between sexes, independent of treatment. Results highlight a need for further investigation of molecular biomarker variability and robustness in A. anatina.

Effects of industrial effluent on wetland macroinvertebrate community structures near a wastewater treatment facility

Macroinvertebrate communities and environmental variables were examined in wetlands near an industrial wastewater treatment facility to assess impacts from exposure to historical effluents. Baseline wetland assessments were required prior to cleanup of contaminated sediments at the facility. The study included wetlands historically exposed to direct effluent discharge, wetlands exposed to current effluent discharge (at the time of sampling), and reference wetlands. Wetlands were sampled in June, July, and September 2018 using a new macroinvertebrate community monitoring protocol (“Wetland CABIN”) developed by Environment and Climate Change Canada. Macroinvertebrates were counted and identified to Family level. Data were qualitatively analyzed using pie charts and nonmetric multidimensional scaling, as well as quantitatively with the Shannon-Weiner diversity index, the Berger-Parker index and using pollution sensitivity values. Correlations using Spearman rho were also calculated between indices and measured environmental variables. Wetlands near the treatment facility were not significantly different compared to reference sites. Macroinvertebrate communities near the treatment facility appeared to be relatively unimpacted by historical effluent inputs. The Wetland CABIN protocol may be a useful monitoring tool for assessing wetland macroinvertebrate community structure because it allows for standardized approaches to be used to compare temporal changes at contaminated sites or spatially between sites.

The fate of heavy metals and salts during the wet treatment of municipal solid waste incineration bottom ash

Bottom ash contains unfavorable contaminants that could leach into the circulating water used for wet treatment, and its improper disposal of bottom ash could cause ecological pollution. This study was to discuss the partition of heavy metals and salts of bottom ash into circulating water and ash stockpile runoff in wet treatment plants in southern China. The leachability of bottom ash before and after the wet treatment was also investigated. The checked heavy metals Pb, Cu, and Ni and dissolved salts Cl− and SO42− show lower available fractions in leachate from the treated bottom ash than that in raw bottom ash. Circulating water is contaminated by target heavy metals, which the contents of Cu and Pb is higher than its limit for urban wastewater discharge. The circulating water owned the highest concentration of Cl− and SO42−, above10000 mg/L, and 1100 mg/L, which is far higher than the limits. The detected heavy metals, Cl− and SO42− in runoff also exceed the limits for urban wastewater discharge. Locations for bottom ash processing and storage sites should be selected to control and prevent any leaching and runoff impacts. Any runoff and circulation water should be discharged to the lined landfill’s leachate collection system or suitable industrial wastewater treatment facilities.

Implementation of Zero Liquid Discharge Systems in Russian Industry

The article focuses on the implementation of zero liquid discharge (ZLD) systems precluding the pollutant release to the environment at metallurgical, machine-building and metalworking enterprises. The need to change over to such systems is due to two main factors: 1. Significant savings in fresh water used in production; 2. A decrease in the number of all kinds of pollutants reaching the environment with various discharges (purified, insufficiently purified and completely untreated). The main feature of ZLD systems at industrial enterprises is the presence of tailing management facilities, e. g. concentrated wastewater treatment facilities; industrial wastewater sludge treatment facilities; non-recyclable oily wastewater and sludge incineration facilities; reclaimed (recycled) industrial wastewater treatment facilities etc. The development stages of ZLD systems in Russia are presented. In 1973, for the first time in the world’s practice, in the Verkh-Isetsky Metallurgical Plant in the city of Sverdlovsk (now Yekaterinburg), the ZLD developed by Prof. V. I. Aksenov and his colleagues was launched and has successfully operated in the cold rolled transformer steel workshop. As an example of wastewater treatment facility as part of a ZLD system, some technical installation solutions are described in order to treat chemically contaminated acid ferrous-containing wastewater generated in pickling carbon steel. The focus is on the feasibility of implementing local ZLD systems instead of central ZLD systems. The advantages of such local systems are: possible regenerating exhausted process solutions at the place of their formation, obtaining demineralized water, the local treatment of chemically polluted wastewater, lower investment and operating costs.

Lower-temperature preparation of SiC ceramic membrane using zeolite residue as sintering aid for oil-in-water separation

Due to their excellent attributes of high water permeance, good stability and antifouling properties, silicon carbide (SiC) membranes have achieved widespread application in industrial wastewater treatment facilities. However, the high sintering temperature (usually beyond 2000 °C) during the preparation of porous silicon carbide is a challenge for the transfer of the technology from the laboratory to industry. An efficient sintering additive method was proposed herein to address this issue. Inexpensive residues (containing oxides of sodium, aluminum and silicon) from an NaA zeolite production line were used as the sintering additives to make the SiC particles more tightly connected due to the formation of new phases. Thus, a SiC network could be formed during an in-situ reaction at lower sintering temperature (e.g., 1000 °C) in air without inert gas protection. The as-prepared SiC membranes exhibited a high pure water permeance of 3700 L m-2 h-1 bar-1 and open porosity of 46%. The mechanical strength of the membrane reached 45 MPa. After alkali corrosion or thermal shock resistance tests, the bending strength was maintained at least 38 MPa. The membrane with a mean pore size of 0.4 μm exhibited a high rejection rate to oil droplets (˃ 90%) in various oil-in-water emulsions with a high water permeance. Membrane cleaning with an ultrasonic treatment resulted in good stability in long-term filtration tests. The utilization of zeolite residues successfully reduced the operational cost of heating during ceramic membrane fabrication with recycled solid wastes. Hence, the proposed preparation method for SiC membranes has good sustainability and is scalable for oil-water separation applications.

The applicability of bio-carrier BioChip in Sequencing Batch Reactors

Introduction. All over the world, the microbial biofilm has been regularly applied to modify urban and industrial wastewater treatment facilities that have aeration tanks. Unlike the activated sludge technology, the biofilm contains a substantial number of bacteria because microorganisms get attached to the surface of the material and grow there. The co-authors share their opinion about the BioChip, applied inside SBR, a sequencing batch reactor. This technology contemplates the use of free-floating activated sludge when all water treatment phases are concentrated inside one tank.
 Materials and methods. To assess the usability of the BioChip inside the SBR reactor, experiments were conducted in an attempt to remove two types of contaminants: organic substances inside the standard model of an SBR reactor, and biogenic elements, in particular, ammonium nitrogen, in the course of developing an anoxic zone in a modified model of the SBR reactor. The per-unit speed of substrate recycling, nitrification and denitrification is determined as a result of the analysis of the quality of wastewater and treated water.
 Results.The experiment conducted using the laboratory model of the SBR reactor has proven the water treatment efficiency within the range of 80–90 % in terms of organic substances and 75–85 % in terms of ammonium nitrogen. Inside the SBR reactor, that had a BioChip installed, the per-unit denitrification speed inside the reactor reached 0.3 to 0.4 N/kg of sludge/day, for the process of nitrification, the value of speed varies from 0.18 to 0.2 kg N/kg of sludge/day. Per-unit speed values and the nitrogen balance equation inside the SBR reactor suggest the SBR operating mode at the capacity of 1.5–2.5 kg of the biological oxygen demand–TKN/kg of sludge/day.
 Conclusions. Low costs, smooth transportation and use in combination with the pre-set SBR reactor with a view to intensification of water treatment efficiency are the main strengths of the BioChip. The operation of the SBR reactor in combination with the BioChip and nitrification/denitrification phases requires highly skilled personnel.

KKR and XPV Water Partners form wastewater treatment platform

Investment firm KKR and Canada's XPV Water Partners have established a platform to provide end-to-end nutrient management solutions for municipal and industrial wastewater treatment facilities.

Miniaturized Ceramic-Based Microbial Fuel Cell for Efficient Power Generation From Urine and Stack Development.

One of the challenges in Microbial Fuel Cell (MFC) technology is the improvement of the power output and the lowering of the cost required to scale up the system to reach usable energy levels for real life applications. This can be achieved by stacking multiple MFC units in modules and using cost effective ceramic as a membrane/chassis for the reactor architecture. The main aim of this work is to increase the power output efficiency of the ceramic based MFCs by compacting the design and exploring the ceramic support as the building block for small scale modular multi-unit systems. The comparison of the power output showed that the small reactors outperform the large MFCs by improving the power density reaching up to 20.4 W/m3 (mean value) and 25.7 W/m3 (maximum). This can be related to the increased surface-area-to-volume ratio of the ceramic membrane and a decreased electrode distance. The power performance was also influenced by the type and thickness of the ceramic separator as well as the total surface area of the anode electrode. The study showed that the larger anode electrode area gives an increased power output. The miniaturized design implemented in 560-units MFC stack showed an output up to 245 mW of power and increased power density. Such strategy would allow to utilize the energy locked in urine more efficiently, making MFCs more applicable in industrial and municipal wastewater treatment facilities, and scale-up-ready for real world implementation.

SCALE DEPOSITS FROM PALM OIL MILL EFFLUENT (POME) TREATMENT AND VARIOUS OTHER INDUSTRIES: A DEVELOPMENTAL REVIEW

The palm oil mill effluent (POME) treatment process is exposed to the formation of crystal-like deposits where their accumulation could create a significant threat to achieving an efficient POME treatment. This article reviewed similar occurrences in other industries, discussed factors influencing the crystal formation and suggested possible solutions to be applied in the oil palm industry. From the review, it was found that crystal deposits have always been a nuisance and sometimes a significant threat to similar industries such as industrial, agricultural and municipal wastewater treatment facilities. Other industries where there is a handling process of certain type of fluids such as heat transfer and oil reservoir drilling fluids also faces similar problems. The article also presented the spectrum of methods for mitigation and removal of the crystal formed. For many cases, nutrient recovery through struvite precipitation has become attractive as it not only reduces crystal growth but at the same time prevents excessive nutrients discharge to the environment. Further exploitation of the recovered struvite as a fertiliser source could possibly generate additional income to the oil palm industry.

Treatment of acidic sulfate-containing wastewater using revolving algae biofilm reactors: Sulfur removal performance and microbial community characterization

Industries such as mining operations are facing challenges of treating sulfur-containing wastewater such as acid mine drainage (AMD) generated in their plant. The aim of this work is to evaluate the use of a revolving algal biofilm (RAB) reactor to treat AMD with low pH (3.5–4) and high sulfate content (1–4 g/L). The RAB reactors resulted in sulfate removal efficiency up to 46% and removal rate up to 0.56 g/L-day, much higher than those obtained in suspension algal culture. The high-throughput sequencing revealed that the RAB reactor contained diverse cyanobacteria, green algae, diatoms, and acid reducing bacteria that contribute the sulfate removal through various mechanisms. The RAB reactors also showed a superior performance of COD, ammonia and phosphorus removal. Collectively, the study demonstrated that RAB-based process is an effective method to remove sulfate in wastewater with small footprint and can be potentially installed in municipal or industrial wastewater treatment facilities.

Effects of calcium carbonate on pyrolysis of sewage sludge

This study demonstrates that calcium carbonate (CaCO3) allows not only enhancement of the production of CO as syngas, but also reduction of the content of polycyclic aromatic hydrocarbons (PAHs) in the pyrolytic products from sewage sludge. CO2 was formed by the decomposition of CaCO3 in pyrolysis. The CO2 derived from CaCO3 enhanced thermal cracking of volatile organic carbons (VOCs) generated during the pyrolysis of sewage sludge and provided an additional source of C and O, likely enhancing the production of CO at >650 °C. In addition, more solid product was converted into gaseous and liquid products by the addition of CaCO3 in the pyrolysis of sewage sludge. This work suggests that CaCO3 can be used as an inexpensive source of CO2 that increases thermal efficiency of the pyrolysis process and reduces the evolution of harmful chemical species such as PAHs during thermal treatment of the byproduct during processing at municipal and industrial wastewater treatment facilities (i.e., sewage sludge).