Optimization of dye-contaminated wastewater treatment by fungal Mycelial-light expanded clay aggregate composite.

Dye-contaminated wastewaters from the printing batik industry are hazardous if discharged into the environment without any treatment. Finding an optimization and reusability assessment of a new fungal-material composite for dye-contaminated wastewater treatment is important for efficiency. The study purposes to optimize fungal mycelia Trametes hirsuta EDN 082 - light expanded clay aggregate (myco-LECA) composite for real priting batik dye wastewater treatment by using Response Surface Methodology with Central Composite Design (RSM-CCD). The factors included myco-LECA weight (2-6 g), wastewater volume (20-80 mL), and glucose concentration (0-10%) were applied for 144 h of incubation time. The result showed that the optimum condition was achieved at 5.1 g myco-LECA, at 20 mL wastewater, and at 9.1% glucose, respectively. In this condition, the decolorization values with an incubation time of 144 h were 90, 93, and 95%, at wavelengths 570, 620, and 670 nm, respectively. A reusability assessment was conducted for 19 cycles and the result showed that decolorization effectiveness was still above 96%. GCMS analysis showed the degradation of most compounds in the wastewater and the degradation products of the wastewater demonstrated detoxification against Vigna radiata and Artemia salina. The study suggests that myco-LECA composite has a good performance and therefore is a promising method for the treatment of printing batik wastewater.

Enhancing the Biological Oxidation of H2S in a Sewer Pipe with Highly Conductive Concrete and Electricity-Producing Bacteria.

Hydrogen sulfide (H2S) generated in sewer systems is problematic to public health and the environment, owing to its corrosive consequences, odor concerns, and poison control issues. In a previous work, conductive concrete, based on amorphous carbon with a mechanism that operates as a microbial fuel cell was investigated. The objective of the present study is to develop additional materials for highly conductive concrete, to mitigate the concentration of H2S in sewer pipes. Adsorption experiments were conducted to elucidate the role of the H2S reduction. Additionally, electricity-producing bacteria (EPB), isolated from a municipal wastewater treatment plant, were inoculated to improve the H2S reduction. The experimental results showed that inoculation with EPB could decrease the concentration of H2S, indicating that H2S was biologically oxidized by EPB. Several types of new materials containing acetylene black, or magnetite were discovered for use as conductive concrete, and their abilities to enhance the biological oxidation of H2S were evaluated. These conductive concretes were more effective than the commercial conductive concrete, based on amorphous carbon, in decreasing the H2S concentration in sewer pipes.

Influence of Salts on the Photocatalytic Degradation of Formic Acid in Wastewater.

Conventional wastewater treatment technologies have difficulties in feasibly removing persistent organics. The photocatalytic oxidation of these contaminants offers an economical and environmentally friendly solution. In this study, TiO2 membranes and Ag/TiO2 membranes were prepared and used for the decomposition of dissolved formic acid in wastewater. The photochemical deposition of silver on a TiO2 membrane improved the decomposition rate. The rate doubled by depositing ca. 2.5 mg of Ag per 1 g of TiO2. The influence of salinity on formic acid decomposition was studied. The presence of inorganic salts reduced the treatment performance of the TiO2 membranes to half. Ag/TiO2 membranes had a larger reduction of ca. 40%. The performance was recovered by washing the membranes with water. The anion adsorption on the membrane surface likely caused the performance reduction.

Effects of Stepwise Temperature Shifts in Anaerobic Digestion for Treating Municipal Wastewater Sludge: A Genomic Study.

In wastewater treatment plants (WWTP), anaerobic digester (AD) units are commonly operated under mesophilic and thermophilic conditions. In some cases, during the dry season, maintaining a stable temperature in the digester requires additional power to operate a conditioning system. Without proper conditioning systems, methanogens are vulnerable to temperature shifts. This study investigated the effects of temperature shifts on CH4 gas production and microbial diversity during anaerobic digestion of anaerobic sewage sludge using a metagenomic approach. The research was conducted in lab-scale AD under stepwise upshifted temperature from 42 to 48 °C. The results showed that significant methanogen population reduction during the temperature shift affected the CH4 production. With 70 days of incubation each, CH4 production decreased from 4.55 L·g-1-chemical oxygen demand (COD) at 42 °C with methanogen/total population (M·TP-1) ratio of 0.041 to 1.52 L·g-1 COD (M·TP-1 ratio 0.027) and then to 0.94 L·g-1 COD ( M·TP-1 ratio 0.026) after the temperature was shifted to 45 °C and 48 °C, respectively. Methanosaeta was the most prevalent methanogen during the thermal change. This finding suggests that the Methanosaeta genus was a thermotolerant archaea. Anaerobaculum, Fervidobacterium, and Tepidanaerobacter were bacterial genera and grew well in shifted-up temperatures, implying heat-resistant characteristics.

Influence of Particle Size and Zeta Potential in Treating Highly Coloured Old Landfill Leachate by Tin Tetrachloride and Rubber Seed.

Old leachate normally has a low organic compound content, poor biodegradability and is hard to biologically treat. The efficacy of tetravalent metal salts as a coagulant and the application of a natural coagulant as a flocculant in landfill leachate treatment is still inconclusive. Hence, this study aimed to evaluate the potential application of tin tetrachloride (SnCl4) as the main coagulant and the rubber seed (Hevea brasiliensis) (RS) as the natural coagulant aid as the sole treatment in eradicating highly coloured and turbid stabilised landfill leachate present at one of the old local landfills in Malaysia. The standard jar test conducted revealed that SnCl4 was able to eliminate 99% and 97.3% of suspended solids (SS) and colour, respectively, at pH8, with 10,000 mg/L dosages, an average particle size of 2419 d·nm, and a zeta potential (ZP) of -0.4 mV. However, RS was found to be ineffective as the main coagulant and could only remove 46.7% of SS and 76.5% of colour at pH3 with 6000 mg/L dosages, and also exhibited smaller particles (933 d·nm) with ZP values of -6.3 mV. When used as a coagulant aid, the polymer bridging mechanism in RS helped in reducing the SnCl4 concentration from 10,000 mg/L to 8000 mg/L by maintaining the same performances. The presence of 1000 mg/L RS as a coagulant aid was able to remove 100% of SS and 97.6% of colour. The study concluded that RS has the potential to be used together with SnCl4 in treating concentrated leachate with SS and colour.

Heavy Metals in Harvested Rainwater Used for Domestic Purposes in Rural Areas: Yatta Area, Palestine as a Case Study.

Rainwater harvesting is considered one of the most important water resources in the Palestinian countryside. In this research, the study area chosen for the study was Yatta town in Hebron city. 75 water samples were collected from 74 cisterns in a number of neighborhoods in Yatta, and a structured household survey was conducted with the same households where the water samples were collected. Statistical analysis was made using the SPSS software. An analysis for the samples was made using ICP-MS to test the existence of a number of heavy metals, namely Pb, Cr, Mn, Co, Ni, Cu, Zn and Cd. The results were compared with the WHO and Palestinian limits for drinking water quality. Considering the metals Mn, Co, Cu and Cd, neither of the samples exceeded any of the two limits. For the metals, Pb, Cr, and Ni, two samples exceeded both limits. For the metal, Zn, one sample exceeded the WHO limit only. Sources of pollution by heavy metals of the harvested rainwater were identified by means of a questionnaire distributed to the households. The results showed that except for nickel and the water collection surface of the cistern factor, there is no direct relationship between the factors and activities that may contribute to contaminate harvested rainwater with heavy metals and the existence of heavy metals beyond local and international limits. Based on the questionnaire and literature: Possible sources of lead and zinc are the roof, storage tanks, distribution systems and plumbing; possible sources of chromium are road dust, asbestos brakes and anthropogenic activities occurring around the house; possible source of nickel is leaching from metals in contact with harvested rainwater such as pipes and fittings which are used to collect the harvested rainwater. In addition, an assessment of the potential health risks due to contamination of the harvested rainwater by heavy metals was made for all the samples that exceeded either WHO limit or the Palestinian limit or both. The Chronic Daily Intake (CDI) and the Health Risk Index (HRI) were calculated. The assessment was made for both adults and children. The results showed that all the samples are considered safe (HRI < 1), which means that there are no potential health risks for consumers.

Chemical waste and allied products.

This paper reviews the related literature reported in 2019 about various types of wastewaters associated with chemical and allied products. The subjects comprise wastewaters produced from various activities in agricultural, chemical, dye, petrochemical, and pharmaceutical. PRACTITIONER POINTS: Bioflocculant chitosan was used for sludge dewatering and the treatment of water and wastewater, and polishing of sanitary landfill leachate. Alkaline lignin-based flocculants were used to achieve excellent color removal for paper mill sludge. Powdered activated coke was used to remove COD (chemical oxygen demand) from chemical industry wastewater effluents.

Chemical Waste and Allied Products.

This review of literature published in 2017 focuses on waste related to chemical and allied products. The topics cover waste management, aerobic treatment, anaerobic treatment, pharmaceutical wastewater, dye wastewater, agricultural wastewater, detergent wastewater, cosmetic wastewater, pigment wastewater.

Poultry Slaughterhouse Wastewater Treatment Using Submerged Fibers in an Attached Growth Sequential Batch Reactor.

In this study, a sequential batch reactor (SBR) with different types of fibers was employed for the treatment of poultry slaughterhouse wastewater. Three types of fibers, namely, juite fiber (JF), bio-fringe fiber (BF), and siliconised conjugated polyester fiber (SCPF), were used. Four SBR experiments were conducted, using the fibers in different reactors, while the fourth reactor used a combination of these fibers. The treatment efficiency of the different reactors with and without fibers on biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonia-nitrogen (NH3-N), phosphorus (P), nitrite (NO2), nitrate (NO3), total suspended solids (TSS), and oil-grease were evaluated. The removal efficiency for the reactors with fibers was higher than that of the reactor without fibers for all pollutants. The treated effluent had 40 mg/L BOD5 and 45 mg/L COD with an average removal efficiency of 96% and 93%, respectively, which meet the discharge limits stated in the Environmental Quality Act in Malaysia.

Chemical Waste and Allied Products.

This review of literature published in 2016 focuses on waste related to chemical and allied products. The topics covered include waste management, aerobic waste treatment, anaerobic waste treatment, air emission, biological waste treatment, groundwater remediation, water recycle, water analysis, water reuse, soil remediation, sorption, physicochemical treatment, ozonation, and fertilizer waste. Future topics include the pollution effect on the environment, especially, to the ecosystem and human as well as improved treatment processes to alleviate the detrimental effects.

Chemical Waste and Allied Products.

This review of literature published in 2015 focuses on waste related to chemical and allied products. The topics cover the waste management, physicochemical treatment, aerobic granular, aerobic waste treatment, anaerobic granular, anaerobic waste treatment, chemical waste, chemical wastewater, fertilizer waste, fertilizer wastewater, pesticide wastewater, pharmaceutical wastewater, ozonation. cosmetics waste, groundwater remediation, nutrient removal, nitrification denitrification, membrane biological reactor, and pesticide waste.

Chemical Waste and Allied Products.

This review of literature published in 2014 focuses on waste related to chemical and allied products. The topics cover the waste management practices, hospital waste, pesticide waste, chemical wastewater, pesticide wastewater and pharmaceutical wastewater. The other topics include aerobic treatment, anaerobic treatment, sorption and ozonation.