Domestic Wastewater Treatment Systems Research Articles

THE FLUCTUATION OF DOMESTIC WASTEWATER DISCHARGED FROM OFFICE BUILDING

The domestic wastewater from office building has been recognized to be different from other sources of wastewater discharge. The objectives of this research were to know the fluctuation of quantity, fluctuation of quality, and a peaking factor of wastewater discharge. The samples were taken from hourly sampling and daily sampling from 7 am to 5 pm and from Monday to Friday during the working time. The results showed that wastewater discharge varied over time and the quantity of Blackwater, greywater and mixed wastewater were ranging from 20.4 to 22.6, 18.7 to 23.3 and 39.61 to 49.93 liter/person/day, respectively. The quality of mixed wastewater varied over time such as for COD, TN, and TP was 252.45±88.96, 85.42±24.08 and 3.01±1.92 mg/L (mean± standard deviation), respectively. The low concentrations were in the morning and peak concentrations were in the afternoon after lunch time. The peaking factor of Blackwater, greywater and mixed wastewater discharge were 1.67, 1.6 and 1.83 at the beginning of working time and the praying time of Muslim Indonesian culture, respectively. It is proposed that domestic wastewater from office building has specific characteristics and the findings of this research can be served as useful information for designing of domestic wastewater treatment system for office buildings.

Removal of landfill leachate ultraviolet quenching substances by electricity induced humic acid precipitation and electrooxidation in a membrane electrochemical reactor

Persistent UV quenching substances (UVQS) in landfill leachate can affect the effectiveness of UV disinfection in domestic wastewater treatment systems when leachate is being co-treated. As a result, effective onsite leachate pre-treatment will have to be implemented to reduce the UV quenching capability. Herein, a membrane electrochemical reactor (MER) was developed and investigated for treating UV quenching organics contained in landfill leachate. Compared to a control reactor that did not have a membrane separator, the MER achieved significantly higher removals of both dissolved organic carbon (61.5 ± 4.1%) and UV254nm absorbance (63.4 ± 8.4%). This enhanced performance was likely due to the combined effects of humic acid precipitation and augmented oxidation of organics. The MER was able to remove 89.1 ± 2.9% of total nitrogen from the leachate while recovering about 51% of the influent ammonia in the catholyte, in comparison to 38.1 ± 4.4% of total nitrogen removal by the control reactor. The MER consumed significantly less electrical energy with specific energy consumption of 70.62 kWh kg−1 DOC or 33.03 kWh kg−1 sCOD, compared to that of the control reactor (211.8 kWh kg−1 DOC or 55.02 kWh kg−1 sCOD). A current density of 20 mA cm−2 was considered optimal in terms of both UVQS removal and energy efficiency. Consideration should be given to the spacing of electrodes to minimize internal resistance and also to avoid trapping of the produced gas bubbles. These results collectively suggest that the MER is a promising onsite pretreatment approach for landfill leachate and further exploration of this technology should be encouraged.

Application of a novel, continuous-feeding ultraviolet light emitting diode (UV-LED) system to disinfect domestic wastewater for discharge or agricultural reuse

In many low-income countries, the poor conditions of sanitation systems have been a significant cause of mortality since they accelerate waterborne disease transmission. Developing sanitation systems in these countries is a pressing concern in both the public and private sectors.This research investigated a decentralized domestic wastewater treatment system using ultraviolet light-emitting diodes (UV-LEDs). Although UV-LED disinfection has become more widespread in recent years, it is a novel approach for domestic wastewater treatment. Domestic wastewater was pretreated by a low-cost pretreatment system with an inclined settler and a sand filter prior to feeding a novel flow-through UV LED reactor. At an inlet flow rate of 30 L/h, the COD, TSS, and turbidity of the effluent were 17.7 mg/L, 3.0 mg/L, and 3.9 NTU, respectively. UV transmittance at 285 nm was enhanced from 29.1% to 70.4%, improving the influent quality for UV LED disinfection.The flow-through UV LED reactor was operated at various flow rates from 10 to 50 mL/min, resulting in applied UV doses of 69.4 to 47.8 mJ/cm2 respectively. These doses are sufficient for inactivating total coliforms in the wastewater to meet the water reuse guidelines for agriculture for both processed food crops and non-food crops.Fouling, which was observed starting at 2 d of operation, decreased the disinfection efficacy to 27% after 25 days of continuous operation. Of the fouling layer, 67% was attributed to organic matter, in contrast to previous fouling studies with mercury UV lamps in which the fouling layer consisted primarily of inorganic compounds. The fouling was reversed by off-line citric acid cleaning for 4 h after every 400 h of continuous operation.

Comparison of Environmental Efficiency of Domestic Wastewater Treatment Systems in a Factory of Indonesia Based on LCA

Comparison of Environmental Efficiency of Domestic Wastewater Treatment Systems in a Factory of Indonesia Based on LCA

Using coconut husks in a full-scale decentralized wastewater treatment system: The influence of an anaerobic filter on maintenance and operational conditions of a sand filter

The critical situation of domestic wastewater treatment in the rural areas of Brazil stimulates the development or improvement of on-site systems using cheap and sustainable materials that can be applied in small and isolated communities. Although this is an important theme, few real scale systems have been studied. This study investigated a full-scale on-site domestic wastewater treatment system composed of a septic tank, an anaerobic filter filled with green coconut husks (Cocos nucifera) and an intermittent sand filter. The experiment was conducted in a rural area located in the city of Campinas (Brazil) and the system was built to serve a small community. The quality of the effluent generated by this combination is in accordance with Brazilian and European legislation and even allows for its reuse in agricultural activities. The results also demonstrate the feasibility of using coconut husks in anaerobic filters, providing a new and more sustainable destination for this material, which is normally treated as solid waste. The combination was shown to be a viable technology for small communities.

Vertical flow constructed wetland planted with Heliconia psittacorum used as decentralized post-treatment of anaerobic effluent in Southern Brazil

In order to investigate the potential of vertical flow constructed wetlands (VFCWs), a 24.5 m2 surface area filled with gravel and planted with Heliconia psittacorum, was implemented as an experimental system for domestic wastewater treatment in southern Brazil. The aims of the study were to (i) evaluate the performance of a full scale system septic tank (ST) and VFCW for decentralized domestic wastewater treatment, and (ii) identify the influence of Heliconia for hydraulic characteristics and consequent performance of the VFCW. The applied load rates in the VFCW were, on average, 10 g biochemical oxygen demand (BOD) m−2 day−1, 4 g NH4+-N m−2 day−1 and a hydraulic loading rate (HLR) of 60 mm day−1. Physicochemical analyses of wastewater treatment were carried out through grab sample methodology, for 5 months. Additionally, hydrodynamic tests were performed during plant development using rhodamine. The study demonstrated the viability of the system for decentralized wastewater treatment in Brazil, with average removal efficiencies of 78% for chemical oxygen demand (COD) and 84% for total suspended solids (TSS), according to national effluent discharge regulations. In spite of media’s large size, the VFCW achieved good average removal efficiencies. The tracer test results showed that the VFCW average hydraulic detention time increased as plants grew. This may have occurred due to interception of wastewater applied on the macrophyte’s leaves as well as a reduction in filter media permeability caused by the spread of roots and rhizomes. These results indicate that the plants played an important role in increasing wastewater contact time in wetlands with high hydraulic conductivity such as a gravel VFCW.

The use of water spinach (Ipomoea aquatica) in domestic wastewater treatment

The main objective of this study was to examine the efficacy and capacity of using hydroponic systems in municipal pollutant removal at household scale. Three pilot scaled hydroponic systems [dimension for each system: 4.5 m (L) x ɸ 114 mm] were installed to investigate the optimal age of vegetable, planting density and retention time for household wastewater treatment, respectively. Water spinach (Ipomoea aquatica) planted in 27 plastic cups throughout 4.5-m-length and 114-mm-diameter uPVC pipes filled with wastewater was employed as the treating agent of pollutants. The averaged influent contained proximately 32.5 mg/L suspended solids (SS), 76.0 mg/L biological oxygen demand (BOD5), 220.5 mg/L chemical oxygen demand (COD), 26 mg/L NH_4^+, 5.0 mg/L NO_3^- , and 8.5 mg/L PO_4^(3-) at pH 7.3. Results showed that a designed system consisting of 10 plants of 15-day-old water spinach pre-planted in baked clay in each cup could treat 30 L of domestic wastewater meeting the current municipal wastewater discharge standards in Vietnam (column A standards of QCVN 14:2008/BTNMT) after 4 days of wastewater retention time. If operated under conditions of the above parameters, the pilot-plant hydroponic system can achieve the removal of 65% SS, 82% BOD5, 74% COD, 90% NH_4^+, 30% NO_3^- and 86% PO_4^(3-). The result of this study has provided an applicable domestic wastewater treatment system ecofriendly and suitable for small and medium household areas.

Seasonal bacterial community succession in four typical wastewater treatment plants: correlations between core microbes and process performance

To understand the seasonal variation of the activated sludge (AS) bacterial community and identify core microbes in different wastewater processing systems, seasonal AS samples were taken from every biological treatment unit within 4 full-scale wastewater treatment plants. These plants adopted A2/O, A/O and oxidation ditch processes and were active in the treatment of different types and sources of wastewater, some domestic and others industrial. The bacterial community composition was analyzed using high-throughput sequencing technology. The correlations among microbial community structure, dominant microbes and process performance were investigated. Seasonal variation had a stronger impact on the AS bacterial community than any variation within different wastewater treatment system. Facing seasonal variation, the bacterial community within the oxidation ditch process remained more stable those in either the A2/O or A/O processes. The core genera in domestic wastewater treatment systems were Nitrospira, Caldilineaceae, Pseudomonas and Lactococcus. The core genera in the textile dyeing and fine chemical industrial wastewater treatment systems were Nitrospira, Thauera and Thiobacillus.

A Review of Phosphorus Removal Technologies and Their Applicability to Small-Scale Domestic Wastewater Treatment Systems

The removal of phosphorus (P) from domestic wastewater is primarily to reduce the potential for eutrophication in receiving waters, and is mandated and common in many countries. However, most P-removal technologies have been developed for use at larger wastewater treatment plants that have economies-of-scale, rigorous monitoring, and in-house operating expertise. Smaller treatment plants often do not have these luxuries, which is problematic because there is concern that P releases from small treatment systems may have greater environmental impact than previously believed. Here P-removal technologies are reviewed with the goal of determining which treatment options are amenable to small-scale applications. Significant progress has been made in developing some technologies for small-scale application, namely sorptive media. However, as this review shows, there is a shortage of treatment technologies for P-removal at smaller scales, particularly sustainable and reliable options that demand minimal operating and maintenance expertise or are suited to northern latitudes. In view of emerging regulatory pressure, investment should be made in developing new or adapting existing P-removal technologies, specifically for implementation at small-scale treatment works.

Efficacy of a national hydrological risk communication strategy: Domestic wastewater treatment systems in the Republic of Ireland

A significant body of research has focused on the role of domestic wastewater treatment systems (DWWTSs) as sources of human-specific aquatic contaminants in both developed and developing regions. However, to date few studies have sought to investigate the awareness, attitudes and behaviours of DWWTS owners and the efficacy of associated communication initiatives. The current study provides an examination of a public national engagement campaign undertaken in the Republic of Ireland which seeks to minimise the impact of DWWTSs on human and ecological health via concurrent inspection and information dissemination. Overall, 1634 respondents were surveyed using a “before and after” study design to capture if and how awareness, attitudes and behaviours evolved over time. Findings suggest that whilst the campaign provided a modest baseline to raise general awareness associated with the basic operational and maintenance requirements of DWWTS, there has been little or no behavioural engagement as a result, suggesting a significant awareness-behaviour gap. Accordingly, efforts to minimise potential human and ecological impacts have been unsuccessful. Moreover, results suggest that public attitudes towards water-related regulation and policy became increasingly negative over the study period due to parallel political and economic issues, further complicating future engagement. Future strategies, both in Ireland and further afield, should focus on health-based demographically-focused message framing to achieve significant knowledge and attitudinal shifts amongst specific population cohorts, and thus bring about significant behavioural change. Study findings and recommendations may be used by myriad stakeholders including local, provincial and national authorities to effectively engage with individuals and communities prior to and during implementation of legislative and policy-based instruments within numerous spheres including climate change adaptation, environmental quality, hydrological risk, and hydro-ecology.

Study on the Enhanced Operation of Self-Ventilation-Based Coupling System for Domestic Wastewater Treatment

In this study, a new coupling system of biological filter bed and subsurface-flow constructed wetland based on the self-ventilation network was proposed, and the comparative pollutant removal efficiency at low and high influent concentration of the pilot coupling system with different substrates configurations were investigated. The study found that: The comparison system (b) had better removal rates than that of the original system (a), and the removal rate when treating low influent concentration was 74.10%, 94.14%, 73.57% and 69.53%, while in high influent concentration case was 81.30%, 90.28%, 88.57% and 75.36% for CODCr , NH4+ -N, TN and TP, respectively. The removal of the above main water indexes of the comparison system (b) promoted by 11.00%, 11.55%, 2.69% and 8.09% respectively in low influent concentration case and 4.20%, 9.20%, 7.66% and 13.61% respectively in high influent concentration case when comparing to the original system (a), which showed that the optimized configuration of various kinds of substrates was significant and was more beneficial to the degradation and removal of pollutants. The adsorption and interception function of substrates in the constructed wetland was the main way of phosphorus removal. The function of self-ventilation ensured the amount of DO in the coupling system, making the phosphorus removal was less affected comparing to structure of traditional wetland.

Structure and function of the microbial consortia of activated sludge in typical municipal wastewater treatment plants in winter

To better understand the relationship between the environmental variables and microbial communities of activated sludge, we took winter samples from different biological treatment units (anaerobic, oxic, etc) from the WWTP’s of a number of Chinese cities. Differences in influent organic components and activated sludge microbial communities were identified by gas chromatography-mass spectrometry and high-throughput sequencing technology, respectively. Liquid nitrogen grinding pretreatment of samples was found to aid in the obtaining of a more bio-diversified sample. Influent type and dissolved oxygen concentration influenced the activated sludge microbial community structure. Nitrospira, Caldilineaceae and Anaerolineaceae were highly related to domestic wastewater treatment systems, whereas Thauera was the most abundant putative refractory aromatic hydrocarbon decomposer found in industrial wastewater treatment systems. Within the influent composition, we speculate that Thauera, Macellibacteroides and Desulfomicrobium are the key functional genera of the anaerobic environment of the textile dyeing industry wastewater treatment systems, whilst Thauera and Thiobacillus are key functional microbes in fine chemical wastewater treatment systems.

Suitability of fluorescent whitening compounds (FWCs) as indicators of human faecal contamination from septic tanks in rural catchments

Rural river catchments are impacted by diffuse pollution sources from agricultural practices and on-site domestic wastewater treatment systems (DWWTS), mainly septic tanks. Methods that can distinguish between contamination sources will significantly increase water management efficiency as they will allow for the development and application of targeted remediation measures. Fluorescent whitening compounds (FWC), are used as optical brighteners in laundry detergents and enter the environment through the discharge of domestic wastewater effluents. Due to their human specific source and potential simple fluorometric measurement this represents a very attractive method to be used by state monitoring agencies.In this study the suitability of FWCs as chemical indicators for human faecal contamination has been investigated in rural Irish catchments. It was found that no quantitative measurements are possible for FWCs in natural waters when using simple fluorometric methods. Hence a simple presence/absence approach needs to be applied. The detectability of FWCs was quantified and found to decrease with higher organic matter content of the river water which has its own fluorescence. This enabled the establishment of equations to predict detection limits and assess the method's suitability for individual catchments based on organic matter concentrations. Furthermore a modified photodecay method is suggested that increases sensitivity of the technique by up to 59%. Applications at rural study sites found some removal of FWCs in percolation areas of DWWTSs but they were still detectable 40 cm below the infiltration depth. FWCs were also detected as distinguishable peaks in impacted streams where septic tank effluents have a high contribution to the river flow.

Influence of Chironomid Larvae on Activated Sludge and Nitrogen Removal in Domestic Wastewater Treatment

Chironomid larvae (CL), aquatic invertebrates in freshwater environments are the common macro‐scale organisms in activated sludge wastewater treatment systems. The effects of CL on biomass quantity, sludge characteristics, and nitrogen removal efficiency were investigated in a domestic wastewater treatment system in this study. The batch tests showed that CL induced sludge reduction and enhanced sludge settlement. A maximum sludge weight reduction rate of 42% was achieved at the CL wet‐weight density of 0.5 g CL/g total suspend solid (TSS), and the sludge volume index (SVI) decreased from 146 to 78 mL/g as the CL wet‐weight density increased from 0 to 0.5 g CL/g TSS. After 52 operation cycles, the system with the CL density of 0.5 g CL/g TSS had a lower sludge yield (0.22 g volatile suspended solid (VSS)/g removed chemical oxygen demand (CODremoved) than the control reactor without CL addition (0.34 g VSS/g CODremoved). Addition of CL enhanced the simultaneous nitrification and denitrification (SND), but partially inhibited nitrification.

Design of the wastewater treatment system of an office building

The MIPA Tower office building, an eleven-storey building, which is located in the area of Institut Teknologi Sepuluh Nopember Surabaya, is under construction. The building will be utilized for offices, classrooms, and laboratories. In the operation of the building, domestic and laboratory wastewater will be produced. This wastewater contains compounds that can pollute the environment. A design of domestic and laboratory wastewater treatment system is conducted. The system comprises of a neutralization tank, a grease trap, an equalization tank, an anaerobic filter, and an activated carbon and silica sand filter.
 The steps of the design are (i) collecting primary data and secondary data, (ii) calculating the engineering design, (iii) drawing the Detailed Engineering Design (DED), and (iv) calculating the bill of quantity and budget.
 The conclusion of this design is that the treatment plant will treat a mixture of domestic and laboratory wastewater. The dimension of each unit is as follows: (i) the neutralization tank (Ø = 0.65 m, H = 0.43 m), (ii) the grease trap (4 m x 2 m x 1 m), (iii) the equalization tank (10.5 m x 5.5 m x 2.5 m), (iv) the septic tank (4.5 m x 4 m x 2.5 m), (v) the six-compartment anaerobic filter (2.25 m x 4 m x 2.5 m), and (vi) the filter with activated carbon (H = 50 cm), silica sand (H = 150 cm), and gravel (H = 10 cm), with the diameter of the tank is 1.5 m.

An integrated algal-bacterial system for the bio-conversion of wheat bran and treatment of rural domestic effluent

Environmental pollution caused by wheat bran and domestic effluent are two common problems in many rural areas. This work combines the digestion of wheat bran and the treatment of rural domestic effluent by developing a microbiological system consisting of Chlorella vulgaris and Bacillus sp., which was isolated from wheat bran fermentation and identified by molecular technique. Bacillus sp. converts solid organics of wheat bran into soluble nutrients which are essential to algae growth. The addition of digested wheat bran balances the nutrients profile of rural domestic effluent and increases the biomass yield of algae. After treatment, the rural domestic effluent was converted into farmland irrigation water and valuable algal biomass was produced. In practice, the results of this work may be useful in reconstructing domestic wastewater treatment systems in some rural areas.

Health and water quality benefits of alternative sewerage systems in Metro Manila, Philippines

This paper presents results of a household survey on the current sanitation and sewerage conditions in Metro Manila. The survey included a choice, measured in terms of the marginal willingness to pay (MWTP), between two alternative domestic wastewater treatment systems: 1) a sewerage system connecting individual households to a treatment plant through sewer lines; and 2) a combined drainage–sewerage system in which wastewater effluent flows with rainwater through flood canals and is intercepted for treatment only at a certain point in the waterway. With the second, the health improvement effect may be limited, but the cost can be significantly lower. The finding in favour of the combined drainage–sewerage system lends some support to this new approach in municipal wastewater treatment, which some other increasingly congested metropolises in Asian countries are likewise adopting, as an alternative to the more costly individual household sewer connections.

Use of a duckweed pond for the domestic wastewater polishing in Ilha Solteira, SP, Brazil

PurposeThe purpose of this paper is to evaluate the efficiency of a duckweed pond in the polishing of a stabilization pond effluent, as well as quantify its biomass production. Once an adequate destination is given to the produced biomass, the wastewater treatment plant can work in a sustainable and integrated way.Design/methodology/approachThe duckweed pond consisted of a tank with volume 0.44 m3, operating in continuous flow with an outflow of 0.12 m3/day and hydraulic retention time of 3.8 days. Effluent samples were collected before and after the treatment, with analyzes made: daily-pH, dissolved oxygen and temperature; twice a week – total nitrogen (TN), total phosphorus (TP) and chemical oxygen demand (COD); and weekly – total solids (TS) and Biochemical Oxygen Demand (BOD5). The duckweeds were collected each for seven days for its production quantification.FindingsThe highest efficiency of TN, TP, COD, BOD5 and TS removal were of 74.67, 66.18, 88.12, 91.14 and 48.9 percent, respectively. The highest biomass production rate was 10.33 g/m2/day in dry mass.Research limitations/implicationsThere was great variation in biomass production, which may be related to the stabilization pond effluent conditions. The evaluation of the effluent composition, which will be treated with duckweeds, is recommended.Practical implicationsThe evaluated treatment system obtained positive results for the reduction in the analyzed variables concentration, being an efficient technology and with operational simplicity for the domestic effluent polishing.Originality/valueThe motivation of this work was to bring a simple system of treatment and to give value to a domestic wastewater treatment system in a way that, at the same time the effluent polluter level is reduced and it is also possible to produce biomass during the treatment process.

Population dynamics of “Candidatus Accumulibacter phosphatis” under the modes of complete nitrification and partial nitrification (nitritation) in domestic wastewater treatment system

In order to understand the enhanced biological phosphorus removal in a continuous-flow domestic wastewater treatment system, population dynamics of “Candidatus Accumulibacter phosphatis” using polyphosphate kinase (ppk1) gene as genetic marker was investigated under the modes of complete nitrification and partial nitrification (nitritation). Nitritation was achieved at hydraulic retention time (HRT) of 6.49h and dissolved oxygen (DO) of 0.5mg O2/L. Denitrifying phosphate removal via nitrite pathway caused low PHAs consumption. Regardless of change of nitrifying modes, phosphorus removal always maintained at a high level of about 100%. Abundance of total Accumulibacter increased along with rising of carbon to nitrogen ratios (C/N). Under good performance of complete nitrification and nitritation, IIC and IID clade affiliated with type II (including clades II A-I) of Accumulibacter lineage was dominant (70%–80%), respectively. Clade IID exhibited high tolerance to starving, oxygen-limiting and high nitrite accumulation, and thus became dominant clade under insufficient carbon sources, low DO and nitritation mode. Clade IIC had a positive correlation with C/N ratios, and IIF had a positive correlation with temperature (p<0.05). Shannon index under nitrification and nitritation mode was 3.54 and 2.38, respectively. That indicated the change of Accumulibacter diversities under different operational conditions.

Non-woven fabric filters integrated with decentralized system for domestic wastewater treatment

Non-woven fabric filters integrated with decentralized system for domestic wastewater treatment