scholarly journals Association of septic tank and sand filter for wastewater treatment: full-scale feasibility for decentralized sanitation

2018 ◽  
Vol 8 (2) ◽  
pp. 268-277 ◽  
Author(s):  
Luana Mattos de Oliveira Cruz ◽  
Adriano Luiz Tonetti ◽  
Bianca Graziella Lento Araujo Gomes
Keyword(s):  
Wastewater Treatment ◽  
Rural Areas ◽  
Precast Concrete ◽  
Legal Aspects ◽  
Full Scale ◽  
Septic Tank ◽  
Internal Diameter ◽  
Sand Filter ◽  
Decentralized System ◽  
Operational Conditions

Abstract Worldwide, 70% of the individuals who do not have access to sanitation facilities live in rural areas. A solution for these areas is the use of decentralized systems for wastewater treatment. However, most of the studies about this topic are performed in a laboratory or in pilot scale. This work investigated a full-scale decentralized system. The association of septic tank and sand filter was installed in a rural area in Brazil. Its feasibility, maintenance, and operational conditions were appraised. The septic tank was built with precast concrete rings (inner diameter: 1.90 m; total depth: 2.34 m; useful volume: 4.30 m3). The sand filter was also constructed with precast concrete rings (internal diameter: 1.90 m; surface area: 2.84 m2) and effluent application was intermittent. The hydraulic loading rate of the sand filter was 253 Lm−2day−1. The quality of the effluent met the legal aspects and the system proved to be effective for decentralized sanitation. The final effluent may be reused in agricultural activities; however, the frequency of maintenance of this system should be taken into account.

History and Current Situation of Night Soil Treatment Systems and Decentralized Wastewater Treatment Systems in Japan

2010 ◽  
Vol 5 (4) ◽  
Author(s):  
X.M. Yang ◽  
A. Morita ◽  
I. Nakano ◽  
Y. Kushida ◽  
H. Ogawa
Keyword(s):  
Wastewater Treatment ◽  
Rural Areas ◽  
Urban Areas ◽  
Domestic Wastewater ◽  
Soil Treatment ◽  
Decentralized System ◽  
Decentralized Wastewater Treatment ◽  
Rapid Economic Growth ◽  
Unique System ◽  
Wastewater Treatment Systems

In Japan, night soil, or black water, was formerly used as fertilizer for agriculture. However, during the rapid economic growth that took place after 1960, chemical fertilizers began to be adopted for agriculture and night soil was almost abandoned. How to treat the excess of night soil then became a big challenge to tackle. From that time a variety of night soil treatment technologies have been developed and the Japanese government has actively promoted the construction of night soil treatment facilities all over the country. As measures for domestic wastewater treatment, sewerage systems were spread in high-density urban areas, while a decentralized system called johkasou was diffused in rural areas with low population density. Johkasou is a unique system that was devised in Japan and mainly treats domestic wastewater on-site. Night soil treatment systems and decentralized wastewater treatment systems used in Japan are introduced in this paper, in the hope that the experience acquired in Japan will contribute to improve the sanitation conditions in other countries.

scholarly journals Niche Differentiation among Three Closely RelatedCompetibacteraceaeClades at a Full-Scale Activated Sludge Wastewater Treatment Plant and Putative Linkages to Process Performance

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Veronica R. Brand ◽  
Laurel D. Crosby ◽  
Craig S. Criddle
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Niche Differentiation ◽  
Full Scale ◽  
Pure Oxygen ◽  
Operational Parameters ◽  
Metabolic Potential ◽  
Operational Conditions

ABSTRACTMultiple clades within a microbial taxon often coexist within natural and engineered environments. Because closely related clades have similar metabolic potential, it is unclear how diversity is sustained and what factors drive niche differentiation. In this study, we retrieved three near-complete Competibacter lineage genomes from activated sludge metagenomes at a full-scale pure oxygen activated sludge wastewater treatment plant. The three genomes represent unique taxa within theCompetibacteraceae. A comparison of the genomes revealed differences in capacity for exopolysaccharide (EPS) biosynthesis, glucose fermentation to lactate, and motility. Using quantitative PCR (qPCR), we monitored these clades over a 2-year period. The clade possessing genes for motility and lacking genes for EPS biosynthesis (CPB_P15) was dominant during periods of suspended solids in the effluent. Further analysis of operational parameters indicate that the dominance of the CPB_P15 clade is associated with low-return activated sludge recycle rates and low wasting rates, conditions that maintain relatively high levels of biomass within the system.IMPORTANCEMembers of the Competibacter lineage are relevant in biotechnology as glycogen-accumulating organisms (GAOs). Here, we document the presence of threeCompetibacteraceaeclades in a full-scale activated sludge wastewater treatment plant and their linkage to specific operational conditions. We find evidence for niche differentiation among the three clades with temporal variability in clade dominance that correlates with operational changes at the treatment plant. Specifically, we observe episodic dominance of a likely motile clade during periods of elevated effluent turbidity, as well as episodic dominance of closely related nonmotile clades that likely enhance floc formation during periods of low effluent turbidity.

Planted Soil Filter – A Wastewater Treatment System for Rural Areas

1993 ◽  
Vol 28 (10) ◽  
pp. 133-140 ◽  
Author(s):  
Robert Netter
Keyword(s):  
Wastewater Treatment ◽  
Rural Areas ◽  
Removal Rate ◽  
Extended Period ◽  
Bacterial Count ◽  
Subsurface Water ◽  
Septic Tank ◽  
Total Bacterial Count ◽  
Surface Loading ◽  
Septic Tank Effluent

Three planted soil filters for wastewater treatment (constructed wetlands with subsurface water flow) were investigated over an extended period of time. Each of them was filled with different kinds of soil. The filters were planted with helophytes, and loaded with septic tank effluent, with pre-treated combined sewage respectively. The hydraulic surface loading varied from 4 to 60mm/d and the specific BOD5 mass loading from 0.9 to 8.7g per square metre per day. The purification efficiency varied between 61 and 99% with respect to BOD5 and COD. The elimination of nutrients (Ntot and Ptot) varied between 5 and almost 100%. The removal rate of the total bacterial count, conforms, faecal coliforms and faecal streptococci was significant.

scholarly journals A Mini-Review of Urban Wastewater Treatment in Greece: History, Development and Future Challenges

2020 ◽  
Vol 12 (15) ◽  
pp. 6133
Author(s):  
Charikleia Prochaska ◽  
Anastasios Zouboulis
Keyword(s):  
Wastewater Treatment ◽  
Environmental Sustainability ◽  
Rural Areas ◽  
Wastewater Treatment Plants ◽  
Treated Wastewater ◽  
Septic Tank ◽  
Urban Wastewater ◽  
Tourism Sector ◽  
Future Challenges ◽  
Urban Wastewater Treatment

Although Greece has accomplished wastewater infrastructure construction to a large extent, as 91% of the country’s population is already connected to urban wastewater treatment plants (WWTPs), many problems still need to be faced. These include the limited reuse of treated wastewater and of the surplus sludge (biosolids) produced, the relative higher energy consumption in the existing rather aged WWTPs infrastructure, and the proper management of failing or inadequately designed septic tank/soil absorption systems, still in use in several (mostly rural) areas, lacking sewerage systems. Moreover, the wastewater treatment sector should be examined in the general framework of sustainable environmental development; therefore, Greece’s future challenges in this sector ought to be reconsidered. Thus, the review of Greece’s urban wastewater history, even from the ancient times, up to current developments and trends, will be shortly addressed. This study also notes that the remaining challenges should be analyzed in respect to the country’s specific needs (e.g., interaction with the extensive tourism sector), as well as to the European Union’s relevant framework policies and to the respective international technological trends, aiming to consider the WWTPs not only as sites for the treatment/removal of pollutants to prevent environmental pollution, but also as industrial places where energy is efficiently used (or even produced), resources’ content can be potentially recovered and reused (e.g., nutrients, treated water, biosolids), and environmental sustainability is being practiced overall.

Wastewater Treatment/Reuse in Rural Areas

1993 ◽  
Vol 27 (9) ◽  
pp. 125-130 ◽  
Author(s):  
Atallah S. Kuttab
Keyword(s):  
Drinking Water ◽  
Wastewater Treatment ◽  
Rural Areas ◽  
Urban Areas ◽  
Gaza Strip ◽  
Subsurface Drainage ◽  
Treated Wastewater ◽  
Septic Tank ◽  
The Impact ◽  
Drainage Field

Proper hygiene leading to good health, in urban as well as rural communities, requires that the consumption of drinking water is raised to acceptable levels (UN organizations put it at 40 liters/cap/day). The increase of water availability necessitates the provision of sewage drainage facilities. Urban areas are normally provided with sewerage schemes (sewer lines, treatment plants, etc.). However, it is unrealistic and not cost feasible to construct such sophisticated systems in villages. This is due to limited resources of public funds available to the responsible government agencies. In rural areas, the provision of utilities to drain sewage in a safe way lags behind the provision of water for household activities, including drinking water. This creates severe contamination to the environment of the various villages and reduces the impact of water on the improvement of health. An appropriate wastewater treatment/reuse system, called the Subsurface Drainage Technique (SDT), is described here which was successfully applied, by Save the Children/USA, in several villages on the Israeli Occupied West Bank and Gaza Strip. The system is applicable for individual households with land available in their immediate vicinity. It consists of a watertight septic tank, where primary treatment occurred, followed by a subsurface drainage field in which the secondary treatment took place. The treated wastewater in the drainage field allowed indirect irrigation (below ground level) for surface plants. Local materials were adopted for the construction of the SDT. Villagers themselves were trained to build the various units and therefore were able to maintain their efficient performance. Ongoing monitoring of the plants grown in the drainage field and the testing for bacteriological contamination ensures the safe performance of the technology.

Comparative performance evaluation of full-scale anaerobic and aerobic wastewater treatment processes in Brazil

2009 ◽  
Vol 59 (1) ◽  
pp. 15-22 ◽  
Author(s):  
M. von Sperling ◽  
S. C. Oliveira
Keyword(s):  
Wastewater Treatment ◽  
Statistical Tests ◽  
Full Scale ◽  
Post Treatment ◽  
Uasb Reactor ◽  
Septic Tank ◽  
Actual Behavior ◽  
Treatment Processes ◽  
Aerobic Wastewater Treatment

This article evaluates and compares the actual behavior of 166 full-scale anaerobic and aerobic wastewater treatment plants in operation in Brazil, providing information on the performance of the processes in terms of the quality of the generated effluent and the removal efficiency achieved. The observed results of effluent concentrations and removal efficiencies of the constituents BOD, COD, TSS (total suspended solids), TN (total nitrogen), TP (total phosphorus) and FC (faecal or thermotolerant coliforms) have been compared with the typical expected performance reported in the literature. The treatment technologies selected for study were: (a) predominantly anaerobic: (i) septic tank + anaerobic filter (ST + AF), (ii) UASB reactor without post-treatment (UASB) and (iii) UASB reactor followed by several post-treatment processes (UASB + POST); (b) predominantly aerobic: (iv) facultative pond (FP), (v) anaerobic pond followed by facultative pond (AP + FP) and (vi) activated sludge (AS). The results, confirmed by statistical tests, showed that, in general, the best performance was achieved by AS, but closely followed by UASB reactor, when operating with any kind of post-treatment. The effluent quality of the anaerobic processes ST + AF and UASB reactor without post-treatment was very similar to the one presented by facultative pond, a simpler aerobic process, regarding organic matter.

scholarly journals Laboratory- and full-scale studies on the removal of pharmaceuticals in an aerated constructed wetland: effects of aeration and hydraulic retention time on the removal efficiency and assessment of the aquatic risk

2017 ◽  
Vol 76 (6) ◽  
pp. 1457-1465 ◽  
Author(s):  
Hannele Auvinen ◽  
Wilhelm Gebhardt ◽  
Volker Linnemann ◽  
Gijs Du Laing ◽  
Diederik P. L. Rousseau
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Retention Time ◽  
Rural Areas ◽  
Hydraulic Retention Time ◽  
Aquatic Organisms ◽  
Healthcare Facility ◽  
Surface Flow ◽  
Full Scale ◽  
Small Water

Pharmaceutical residues in wastewater pose a challenge to wastewater treatment technologies. Constructed wetlands (CWs) are common wastewater treatment systems in rural areas and they discharge often in small water courses in which the ecology can be adversely affected by the discharged pharmaceuticals. Hence, there is a need for studies aiming to improve the removal of pharmaceuticals in CWs. In this study, the performance of a full-scale aerated sub-surface flow hybrid CW treating wastewater from a healthcare facility was studied in terms of common water parameters and pharmaceutical removal. In addition, a preliminary aquatic risk assessment based on hazard quotients was performed to estimate the likelihood of adverse effects on aquatic organisms in the forest creek where this CW discharges. The (combined) effect of aeration and hydraulic retention time (HRT) was evaluated in a laboratory-scale batch experiment. Excellent removal of the targeted pharmaceuticals was obtained in the full-scale CW (>90%) and, as a result, the aquatic risk was estimated low. The removal efficiency of only a few of the targeted pharmaceuticals was found to be dependent on the applied aeration (namely gabapentin, metformin and sotalol). Longer and the HRT increased the removal of carbamazepine, diclofenac and tramadol.

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