Municipal Domestic Wastewater Research Articles

Microalgae cultivation in domestic wastewater for wastewater treatment and high value-added production: Species selection and comparison

In this study, six freshwater microalgae, including Scenedesmus sp. LX1, R. subcapitata, T. obliquus, Chlorella sp. HL, Chlorella sp. (A), and Chlorella sp. (B), were appraised for growth, nutrient removal, and high value-added productions in municipal domestic wastewater to select the species with greatest utilization potential. The results showed that after 10 d of cultivation under the sterilized condition, Chlorella grew better than others and Chlorella sp. HL obtained the highest algae density (2.44 × 107 cells/mL). The maximum biomass obtained from Scenedesmus sp. LX1 was 0.55 g/L. The maximum COD removal rate was achieved by R. subcapitata (79.01 %). Scenedesmus sp. LX1 showed excellent NH4+-N and TP remove capacity and achieved the highest removal rate (93.81 % and 87.72 %, respectively) eventually. The harvested biomass was found to accumulate high value-added products, especially protein, with a highest content of 54.64 %, which was observed in T. obliquus. Under the sterilized condition, Scenedesmus sp. LX1 was considered as the optimal candidate for municipal domestic wastewater treatment. Under the non-sterilized condition, Chlorella sp. HL was found to perform better than Scenedesmus sp. LX1 and T. obliquus no matter water purification, algal growth, and high value-added products accumulation.

Research progress of combined anaerobic ammonium oxidation (ANAMMOX) process for nitrogen removal

Anaerobic ammonia oxidation (ANAMMOX) process is an efficient and low-cost biological nitrogen removal process. However, it still faces some challenges in mainstream applications due to the limitation of substrate types and nitrate accumulation. In recent years, the combined process of anammox has been widely studied to solve the above problems. In this paper, the combined processes of anammox developed in recent years are reviewed, and discussed from the process principle, advantages and disadvantages, influencing factors, process extensibility and the key bottlenecks existing in the promotion and application, as well as the relevant work of the subject group. Finally, we take an outlook on the development of the combined anaerobic ammonia oxidation process in municipal domestic wastewater treatment.

Evaluation of the efficiency of an integrated biofilm and phytoremediation system with Nasturtium officinale for the treatment of municipal wastewater in Huancavelica

In this research removal efficiency was evaluated of organic pollutants of a biofilm and phytoremediation integrated system for municipal wastewater treatment in Huancavelica. A pilot plant consisting of a settler was installed that also retained oils and fats, a biological filter using as support material the calcareous stuff and a phytoremediation process with Nasturtium officinale (watercress) The hydraulic retention time was 5.5 hours and the flowrate of 0.011 L s -1, the evaluation was made of the proper functioning of processes by monitoring control parameters. The pollutant removal efficiency was determined by Student's "t" test (p <0.05). An average pH value of 7.57 and a temperature of 12.07 ° C were obtained, subsequently the measurement of BOD5 was initiated, obtaining maximum effluent values of 131 ppm and minimum values of 45 ppm and a removal efficiency of 44.8% was obtained, for COD. In total coliforms, fecal coliforms and Escherichia coli the removal was 66.67%, 94.59%, 81.22% and 72.12% respectively, oil and fat analysis was also performed and total suspended solids, however high removal efficiency was not obtained. It is concluded that the parameters of BOD5 and COD comply with the MPL for the effluents of municipal domestic wastewater treatment plants, while the rest of the parameters analyzed do not comply with the regulations. however high removal efficiency was not obtained. It is concluded that the parameters of BOD5 and COD comply with the MPL for the effluents of municipal domestic wastewater treatment plants, while the rest of the parameters analyzed do not comply with the regulations. however high removal efficiency was not obtained. It is concluded that the parameters of BOD5 and COD comply with the MPL for the effluents of municipal domestic wastewater treatment plants, while the rest of the parameters analyzed do not comply with the regulations.

Successful application of municipal domestic wastewater as a co-substrate in 2,4,6-trichlorophenol degradation

Wastewater containing 2,4,6-trichlorophenol (2,4,6-TCP) is highly toxic and causes harmful effects on aquatic ecosystems and human health. In this study, wastewater containing high levels of 2,4,6-TCP was successfully co-metabolized by introducing municipal domestic wastewater (MDW) as the co-catabolic carbon source. The concentration of degraded 2,4,6-TCP increased from 0 to 208.71 mg/L by adjusting the influent MDW volume during a 150-day-long operation. An MDW dose of 500 mL was found optimal, with an average concentration of 250 mgCOD/L. Unlike the long-term experiment, changing the MDW adding mode in a typical cycle further increased the concentration of 2,4,6-TCP removed to 317 mg/L. The main MDW components, such as the sugars, VFAs, and slowly biodegradable organic substances, improved 2,4,6-TCP degradation, achieving a TOC removal efficiency of 90.98% and a dechlorination efficiency of 100%. The MDW level did not change the 2,4,6-TCP degradation rate (μTCP) in a typical cycle compared to the single carbon source, and the μTCP remained at a high level of 50 mg 2,4,6-TCP/h. Macrogenetic analysis demonstrated that MDW addition promoted the growth of 43 bacterial genera (41.49%) responsible for 2,4,6-TCP degradation and intermediates’ metabolism. The key genes for 2,4,6-TCP metabolism (pcpA, chqB, mal-r, pcaI, pcaF, and fadA) were detected in the activated sludge, which were distributed among the 43 genera. To conclude, this study proposes a new carbon source for co-metabolism to treat 2,4,6-TCP-polluted wastewater.

Evaluation of coagulating efficiency and water borne pathogens reduction capacity of Moringa oleifera seed powder for treatment of domestic wastewater from Zomba, Malawi

For many communities in the developing world, conventional water treatment methods are often unaffordable because of the high cost associated with them and inavailability of chemical coagulants in the developing countries. Employing Moringa oleifera seed (as powder or extracts) to treat municipal domestic wastewater effluent presents an alternative practice to improving water quality effluent of existing wastewater treatment plants in developing countries. In the present study, domestic wastewater from a local wastewater treatment plant in Zomba, Malawi, was treated by Moringa oleifera seed powder in batch tests. The objective was to investigate the potential of Moringa oleifera seed powder in enhancing domestic wastewater treatment through the reduction of microbial load, turbidity and total dissolved solids (TDS). Moringa oleifera powder seed reduced turbidity from 287 to 38.8 Nephelometric turbidity unit (NTU), increased pH from 4.3 to 7.1, and set total dissolved solids (TDS) at standards recommended by World Health Organization guidelines for drinking water. Optimum reduction in microbial load was observed at a dosage of powder of 15 g L−1, with particular potency against Salmonella and Shigella spp. However, each dose of Moringa oleifera seed powder showed its own ideal settling (contact) time for microbe reduction before regrowth of microbes.

The environmental feasibility of low-cost algae-based sewage treatment as a climate change adaption measure in rural areas of SADC countries

Employing specific algae treatment to treat municipal domestic wastewater effluent presents an alternative practice to improving water quality effluent of existing rural pond systems in Southern Africa. In the present study, domestic wastewater was treated by using existing infrastructure and inoculated specific selected algae strains in a pond system treatment plant. The objective was to determine through a field pilot study if algae nutrient treatment efficiencies in current traditional water-stabilisation ponds can be optimised by manipulating the existing natural consortium of algae through mass inoculation of specific algae strains of Chlorella spp. The reduction of total phosphorus in the unfiltered water (contain algae) after specific algae treatment was 74.7 and 76.4% for water-stabilisation ponds 5 and 6, while total nitrogen removal was 43.1 and 35.1%, respectively. Chlorella protothecoides was the dominant algal species in ponds 4, 5 and 6 after specific algae treatment. The maximum algae abundance (4.6 × 106 cells mL−1 in pond 4 and 6.1 × 106 cells mL−1 in pond 5) were observed in August 2016, while the maximum chlorophyll-a concentration of 783 μg L−1 was measured in pond 5 after 2 months of specific algae inoculation. Although the present study showed that inoculation of specific algal strains can potentially enhance the treatment efficiencies of existing rural domestic sewage pond systems, it was also evident from the algae-treated effluent analysis that the algae biomass in the upper surface water layer must be harvested for maximum treatment results.

Nutrients removal from the secondary effluents of municipal domestic wastewater by Oscillatoria tenuis and subsequent co-digestion with pig manure

ABSTRACTBatch experiments were carried out to investigate the performance of Oscillatoria tenuis to remove nitrogen, phosphorus and chemical oxygen demand (COD) from secondary effluents of municipal domestic wastewater. Meanwhile the potential of biogas production by collected O. tenuis co-digested with pig manure was also investigated. O. tenuis had a biomass productivity of 150 mg L−1 d−1, a removal rate of (96.1%), total phosphorus (82.9%) and COD (92.6%) within 7 d at an aeration rate of 1.0 L/min. The biochemical methane potential (BMP) test for O. tenuis fermented with pig manure was evaluated at three different ratios. The cumulative methane yield was 183 mL CH4/gVSadd at a mixing ratio (MR) of 3.0, 191 mL CH4/gVSadd at a MR of 2.0 and 84 mL CH4/gVSadd at a MR of 1.0. The maximum methane yield appeared at the ratio of 2.0. Meanwhile, acid-, alkali- and thermal-pretreatments were applied to raw microalgae biomass to promote biogas production. The highest methane productivity (256 mL CH4/gVSadd) was achieved by the thermal-pretreatment at 120°C, which was about 1.5 times higher than the non-pretreatment group (191 mL CH4/g VSadd).

WASTEWATER COLLECTION PERFORMANCE ON COMMUNAL SANITATION SYSTEM IN CIMAHI INDONESIA

In dense population cities, the effectiveness of the communal system in handling municipal domestic wastewater is important. This research aimed to evaluate the effectiveness of pipe dimensioning process and determine it as a wastewater collector to be served as a reactor through a tracer test. Thus, this work may give some inputs for a reliable design criteria for communal system in Indonesia. The reaserch area was at communal system on Tegal Kawung RT 05 RW 08. It served 37 household which was identified using built drawings and field checking. The number of communal septic tank user was 150 people who approximately use water of 134.33 L/person/day and more than 75% (107.46 L/persons/day )was discharged to the system. The tracer test was done between the control box with the distance of 27.94 m and diameter of 150 mm. Based on the mathematical model that was used, the diameter of the pipe should be 100 mm. The tracer test showed that the piping system is the Plug Flow Reactor but it is not yet effective, shown by the MDI value of 3.36.

Situation analysis of China's wastewater discharge

Great progress has been made in reducing China’s water pollution after decades of efforts. From the perspective of wastewater discharge, the situation of wastewater discharge since 1985 is analysed in this study, with importance attached to industrial wastewater, including wastewater from township enterprises, and to municipal domestic wastewater. In general, the total wastewater discharge in China is still growing year by year, resulting mainly from the increasing municipal domestic wastewater discharge. Industrial wastewater discharge has been under effective control, with the discharge rate that meets standards being higher than 90%. Take township enterprises as an example, their wastewater discharge and chemical oxygen demand (COD) discharge, which for a time accounted for 21% of the total industrial wastewater discharge and 44.3% of the total industrial COD discharge, respectively, have decreased greatly, after taking a series of measures such as shutting down, stopping run, combination and transferr...

Reclamation of municipal domestic wastewater by aquaponics of tomato plants

In search of low-cost eco-tech for the reclamation of municipal domestic wastewater, tomato plants ( Lycopersicum esculentum) were cultivated on the floating bed of pulp-free coconut fiber over four different concentrations of wastewater (25%, 50%, 75% and 100%) and groundwater as control, in 10 L plastic bucket for two months. The study revealed that PO 4-P was removed by 58.14–74.83% with maximum removal at 50% wastewater. More than 75% removal of NO 3-N was observed in all treatments. Both COD and BOD were reclaimed highest at 100% wastewater by 61.38% and 72.03%, respectively. Ammonium-N concentration was subsided below the toxic level in all the treatments. The population of coliform bacteria ( Escherichia coli) was reduced to 91.10–92.18% with maximum efficiency at 100% wastewater. Growth performance was observed relatively better at 100% wastewater. Crop production as the value addition of this technology was also recorded maximum at 100% wastewater. The bioaccumulation of Cd and Ni in tomato crop was far below the threshold level, but the bioaccumulation of Pb and Cr was above the safe level by 80 times and 660 times, respectively. The aquaponically reclaimed water can be reused in agriculture, aquaculture and industries.

The Utilization of Post-chlorinated Municipal Domestic Wastewater for Biomass and Lipid Production by Chlorella spp. Under Batch Conditions

South Africa has a rich microalgal biodiversity which has the potential to be used for renewable bio-fuel production in the region. Bioprospecting for oleaginous microalgae in KwaZulu Natal Province, South Africa, resulted in the establishment of a microalgal culture collection system for alternative energy research in the country. A potential hyper-lipid-producing Chlorella spp. strain was isolated, purified, and cultured in supplemented post-chlorinated wastewater for biomass and lipid production at the laboratory scale under batch mode. The microalgal strain was cultivated in different strengths of BG-11 media supplemented with wastewater from a local municipal domestic wastewater treatment plant. The Chlorella spp. was grown using ambient dissolved carbon dioxide in shake flasks under photosynthetically active radiation (±120 μmol m⁻² s⁻¹). Microalgal biomass and lipid productivity were monitored at 24-h intervals in the batch mode. The microalgal biomass was analyzed by direct light microscopy and indirectly by spectrophotometry at 600 nm, and the lipids were extracted and quantified. The growth rate of the Chlorella spp. was enhanced in post-chlorinated wastewater supplemented with 5 mM NaNO₃ with maximal biomass productivity. A dramatic increase in lipid yield was achieved with the post-chlorinated wastewater supplemented with 25 mM NaNO₃. Low dosages of free chlorine were found to enhance microalgal growth. These findings serve as a basis for further scale-up trials using municipal wastewater as a medium for microalgal biomass and lipid production.

Biogeochemical circulation and management countermeasures of N and P in coastal wetlands of southern Laizhou Bay

在莱州湾南岸滨海湿地的生物地球化学循环过程中，N、P元素主要来源于通过河流输入的工业废水、城市生活污水、农田地表径流、灌溉余水和海水养殖池养殖废水，通过潮上带、潮间带湿地最终被输送到潮下带近海湿地，引起潮下带近海湿地水体N、P含量的不断升高，2000年通过河流输入到莱州湾南岸的N总量为46 271.1 t, P总量为2 092.1 t。潮上带、潮间带自然湿地的底质、土壤和植物对N、P元素有显著的吸收、净化作用。以2000年为例，若不考虑自然湿地的吸收、净化作用，仅靠水体交换、扩散稀释，输送到潮下带近海湿地的N、P在海水中的含量为6.74 mg·L^-1、0.299 mg·L^-1，而当年潮下带近海湿地水体N、P含量实测值分别为0.086 mg·L^-1、0.029 mg·L^-1，计算值分别是实测值的78.4倍、10.3倍;说明自然湿地对输入的N、P有明显的吸收净化效应。为降低莱州湾南岸潮下带近海湿地海水中的N、P含量，提出了发展循环经济，减小莱州湾南岸滨海湿地的N、P输入通量，对自然湿地进行有效的保护和生态恢复，建设人工湿地、提高湿地的环境净化功能等调控措施。

Domestic wastewater influent profiling using mitochondrial real-time PCR for source tracking animal contamination

Real-time PCR amplifying mammalian and avian mitochondrial DNA (mtDNA) was developed to characterize domestic and light industrial wastewater influent from two municipal wastewater treatment facilities (WWTF) over a 24-week period. Influent samples were assayed with species-specific primers and dual-labeled probes for human, bovine, swine, dog, cat, Canada goose and white-tailed deer to detect and quantify eukaryotic mtDNA contributors to local municipal wastewaters. Human (mean = 9.6 × 10 4 copies/ml) and dog (mean = 5.3 × 10 2 copies/ml) mtDNA were detected in all 24 samples (12 samples/site). Bovine and swine mtDNA were detected sporadically and at lower levels than human mtDNA, means = 3.0 × 10 4 and 9.5 × 10 2 copies/ml, respectively. Domestic cat, Canada goose and white-tailed deer were detected only once in 24 samples. Mitochondrial DNA concentrations were compared to other bacterial, chemical and spectrophotometric parameters. Human mtDNA was positively correlated with ammonia concentration ( P = 0.01) and initial OD 600 reading ( P = 0.02) at one WWTF. Bovine mtDNA was positively correlated with biological oxygen demand (BOD) ( P = 0.02), final DNA concentration ( P = 0.03), initial and final humic acid concentrations ( P = 0.01, P = 0.01), and final OD 600 ( P = 0.03) at one WWTF and total suspended solids (TSS) ( P = 0.04, P = 0.09) at both facilities. Fecal coliforms were not positively or negatively correlated with mtDNA concentrations of any species assayed. For source tracking purposes, a combination of human (10 5 copies/ml) and dog mtDNA signal (10 2 copies/ml) could be indicative of municipal domestic wastewater contamination of environmental waters.

Treatment of alligator farm wastewater using land application

Treatment of an aquacultural wastewater from alligator farms in Louisiana using land application was investigated. Wastewater from alligator farms resembled municipal domestic wastewater in high biological oxygen demand (BOD 5) and P concentrations but contained twice the N content due to the high excretion of ammonia by alligators. Land application using overland flow consistently removed BOD 5 and N over a 20 day application period. First-order removal rates for the pollutants were: total soluble P = 0·009/min, BOD 5 = 0·017/min, ammonia = 0·023/min and organic N = 0·027/min. Optimal detention times for a range of discharge limits were calculated assuming first-order removal of the pollutants. P isotherms were used to estimate the lifetime of the treatment system's ability to sorb P. Design calculations using current EPA design criteria indicate that an area of 0·16 ha (approx. 0·4 acres) is needed to treat wastewater from a typical alligator farm. Land application was found to be a viable technique for treating this high-strength wastewater.