Sustainable sewage solutions for small agglomerations

2005 ◽  
Vol 52 (12) ◽  
pp. 25-32 ◽  
Author(s):  
A. Galvão ◽  
J. Matos ◽  
J. Rodrigues ◽  
P. Heath
Keyword(s):  
Wastewater Treatment ◽  
Rural Communities ◽  
Constructed Wetlands ◽  
Rural Areas ◽  
Wastewater Treatment Plants ◽  
Construction Costs ◽  
Small Communities ◽  
Trickling Filters ◽  
Visual Impact ◽  
Surrounding Areas

In a significant number of European countries, the need for providing appropriate treatment for the effluents of small rural communities is still especially relevant. In fact, in countries like Portugal, Spain, and many others, significant amounts of investment will be addressed in the next few years to the construction of small Wastewater Treatment Plants (WWTP). The problems faced when constructing and operating WWTP serving small communities may be relevant when energy and labour costs are relatively high, or when the visual impact on the surrounding areas is especially negative. Sustainable treatment solutions require the selection of appropriate technologies using fewer resources. In this paper, information is presented about sustainability indicators of twenty-one small secondary wastewater treatment plants, including conventional (trickling filters and extended aeration plants) and non-conventional treatment systems (constructed wetlands). The data refer to allocated areas per inhabitant, amounts of concrete per inhabitant, power per inhabitant, and construction and installation costs per inhabitant. The data seem to show that for different reasons, constructed wetlands are promising treatment solutions for application to rural areas in particular because of the relatively low power requirements and relatively low construction costs for served populations below 500 inhabitants.

Small Wastewater Treatment Plants in Switzerland

1990 ◽  
Vol 22 (3-4) ◽  
pp. 1-8
Author(s):  
Markus Boller ◽  
Gieri Deplazes
Keyword(s):  
Wastewater Treatment ◽  
Rural Areas ◽  
Wastewater Treatment Plants ◽  
Basic Information ◽  
Quality Requirements ◽  
Trickling Filters ◽  
Operation And Maintenance ◽  
Local Quality ◽  
New Guidelines ◽  
Receiving Water

In Switzerland, the installation of small treatment plants in rural areas is being and will be intensified. In order to remove the numerous small pollution sites, new guidelines have been established in which basic information is given on the procedure of how to consider local circumstances of wastewater characteristics and of how to integrate local quality requirements of the receiving water into the design of small plants. The statistics on small treatment plants show a preferential application for extended aeration, RBCs and trickling filters. Due to the lack of skilled operation and maintenance, the performance of small treatment plants is not always satisfactory. New economic, reliable and less service-demanding methods are increasingly studied and applied.

Constructed wetlands: a solution to water quality issues in Mexico?

Water Policy ◽  
2015 ◽  
Vol 18 (3) ◽  
pp. 654-669 ◽  
Author(s):  
P. L. García-García ◽  
L. Ruelas-Monjardín ◽  
J. L. Marín-Muñíz
Keyword(s):  
Wastewater Treatment ◽  
Rural Communities ◽  
Constructed Wetlands ◽  
Rural Areas ◽  
Domestic Wastewater ◽  
Current Status ◽  
Academic Institutions ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
The Status

Historically, water sanitation has not been a priority for any sector of society in Mexico, and substantial technical and ecological problems exist in this country's wastewater treatment systems. Constructed wetlands (CWs) have proven to be an exceptional alternative, particularly for rural areas in developing countries. This paper identifies the status of research on CWs in Mexico, and discusses the possibilities for their use. Our review showed that interest in CWs in Mexico is growing exponentially, particularly in academic institutions. Consequently, published documents are mostly on experimental wetlands, although there are a few experienced groups devoted to producing technology and providing training needed to apply CWs. CWs are generally used for domestic wastewater treatment, disregarding other pollution sources such as agriculture and industry. Rural communities have the most potential to obtain and apply this technology, but unfortunately their degree of use of these systems is still very low. The current status of research and application of CWs leads to a few options discussed in this paper to promote their use in Mexico, taking into account that the success of these alternatives can only be achieved by partnering with governments, water treatment companies, non-governmental organizations, academic institutions and rural communities.

Sequencing batch reactors with continuous inflow for small communities in rural areas in Bavaria

1997 ◽  
Vol 35 (1) ◽  
pp. 269-276 ◽  
Author(s):  
P. Schleypen ◽  
I. Michel ◽  
H. E. Siewert
Keyword(s):  
Wastewater Treatment ◽  
Rural Areas ◽  
Wastewater Treatment Plants ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Small Communities ◽  
Buffer Tank ◽  
Practical Experiences ◽  
Current Energy ◽  
Sophisticated Technology

For over two years, special investigations and practical experiences were evaluated at small wastewater treatment plants with SBR-technology in rural areas in Bavaria. The plants are designed for advanced wastewater treatment with extended aeration. Plants of this type are suitable for small treatment plants, which have to cope with stringent treatment requirements and little available land. The machinery and controlling equipment are constructed with highly sophisticated technology. The constant cycles with time fixed process phases have been proved to be sufficient, but the phases should be optimized and adapted individually to an empirically analysed load line for each plant. The composition of the biocenosis was stable and efficient. The amount of filamentous bacteria was not high. The biocenosis of the ciliated protozoa was dominated by free-swimming species. Plants with two reactors and cycle durations of 10 hours should have a buffer tank in front of the reactors in order to equalize the loading of each reactor. A polishing pond should always be built before discharge into the receiving body of water. The investment costs are comparatively low, but the current energy consumption is higher than in activated treatment plants with continuous operation. Although the automatically controlled process requires little continuous assistance, skilled operators are needed for operation, maintenance and manual control.

Evaluation of Small Wastewater Treatment Plants in the County of Århus – Denmark

1993 ◽  
Vol 28 (10) ◽  
pp. 33-41
Author(s):  
Jes la Cour Jansen ◽  
Bodil Mose Pedersen ◽  
Erik Moldt
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Biological Treatment ◽  
Wastewater Treatment Plants ◽  
Chemical Precipitation ◽  
Common Type ◽  
Treatment Efficiency ◽  
Effluent Quality ◽  
Different Types

Influent and effluent data from about 120 small wastewater treatment plants (100 - 2000 PE) have been collected and processed. Seven different types of plants are represented. The effluent quality and the treatment efficiency have been evaluated. The most common type of plant is mechanical/biological treatment plants. Some of them are nitrifying and some are also extended for chemical precipitation of phosphorus. Constructed wetlands and biological sandfilters are also represented among the small wastewater treatment plants.

Using metazoa to reduce sludge production

1997 ◽  
Vol 36 (11) ◽  
pp. 171-179 ◽  
Author(s):  
J. H. Rensink ◽  
W. H. Rulkens
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Domestic Wastewater ◽  
Brewery Wastewater ◽  
Trickling Filters ◽  
Starting Point ◽  
Nitrification Process ◽  
Sludge Production

Pilot plant experiments have been carried out to study the mineralization of sludge from biological wastewater treatment plants by worms such as Tubificidae. Trickling filters filled with lava slags were continuously fed with a certain quantity of excess activated sludge of a Dutch brewery wastewater treatment plant (Bavaria) by recirculation during 10 to 14 days. At the starting point of each experiment the trickling filters were inoculated with Tubificidae. Recirculation of sludge showed that use of Tubificidae resulted in a COD reduction of the sludge (mixed liquor) of 18–67–. Without worms this reduction was substantially lower. The sludge production in a pilot activated sludge system for treating settled domestic wastewater reduced from 0.40 to 0.15 g MLSS/g COD removed when Tubificidae were added to the system. The lower amounts of sludge were always accompanied by an increase of nitrate and phosphate concentration in the wastewater. There was no disturbance of the nitrification process. Application of Tubificidae or other worms may have interesting potential for practical application.

Innovative low cost procedure for nutrient removal as an integrated element of a decentralised water management concept for rural areas

2001 ◽  
Vol 44 (1) ◽  
pp. 105-112 ◽  
Author(s):  
M. Burde ◽  
F. Rolf ◽  
F. Grabowski
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Rural Areas ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Fixed Bed ◽  
Extreme Rainfall ◽  
Fixed Bed Reactor ◽  
Soil Zone

The absence of large rivers with rather high niveau of self purifying effect in parts of east Germany leads to a discharging of the effluent of wastewater treatment plants into the groundwater in many cases. One useful consequence is the idea of realisation of decentralised measures and concepts in urban water resources management concerning municipal wastewater as well as rainfall, precipitation. At the same time, only the upper soil zone - a few decimetres - is water - saturated and thus discharge effective, even when extreme rainfall takes place. Underneath, however, there generally exists an unsaturated soil zone, which is up to now a rather unexplored retardation element of the hydrologic- and substrate-cycle. Nutrient removal in small wastewater treatment plants that are emptying into ground waters is often beneficial. The presented studies optimised an inexpensive method of subsequent enhanced wastewater treatment. The developed reactor is similar to a concentrated subsoil passage. The fixed bed reactor is divided in two sections to achieve aerobic and anoxic conditions for nitrification/denitrification processes. To enhance phosphorus removal, ferrous particles are put into the aerobic zone. Two series of column tests were carried out and a technical pilot plant was built to verify the efficiency of the process. The results show that this method can be implemented successfully.

scholarly journals Effects of the Use of Ornamental Plants and Different Substrates in the Removal of Wastewater Pollutants through Microcosms of Constructed Wetlands

2018 ◽  
Vol 10 (5) ◽  
pp. 1594 ◽  
Author(s):  
Luis Sandoval-Herazo ◽  
Alejandro Alvarado-Lassman ◽  
José Marín-Muñiz ◽  
Juan Méndez-Contreras ◽  
Sergio Aurelio Zamora-Castro
Keyword(s):  
Rural Communities ◽  
Constructed Wetlands ◽  
Rural Areas ◽  
Ornamental Plants ◽  
Oxygen Demand ◽  
Added Value ◽  
Fecal Coliforms ◽  
Zantedeschia Aethiopica ◽  
Wastewater Pollutants ◽  
Pet Substrate

The high costs involved in treating wastewater are problems that developing countries confront, mainly in rural areas. Therefore, Constructed Wetlands (CWs), which are composed of substrate, vegetation, and microorganisms, are an economically and ecologically viable option for wastewater treatment in these places. There is a wide variety of possibilities for substrates and ornamental plants that have not yet been evaluated to be implemented in future CW designs. The goal of this study was to evaluate the process of adaptation and removal of wastewater pollutants in CW microcosms using different terrestrial ornamental plants (Lavandula sp., Spathiphyllum wallisii, and Zantedeschia aethiopica). Those plants were sown in two types of substrate: red volcanic gravel (RVG) and polyethylene terephthalate (PET). CWs with vegetation reduced 5-day biochemical oxygen demand (BOD5) by 68% with RVG substrate and 63% with PET substrate, nitrates 50% in RVG substrate and 35% in PET substrate, phosphates 38% in RVG substrate and 35% in PET substrate, and fecal coliforms 64% in RVG and 59% in PET substrate). In control microcosms without vegetation, reductions were significantly lower than those in the presence of plants, with reduction of BOD5 by 61% in RVG substrate and 55% in PET substrate, nitrates 26% in RVG substrate and 22% in PET substrate, phosphates 27% in RVG substrate and 25% in PET substrate. Concerning fecal coliforms 62% were removed in RVG substrate and 59% in PET substrate. Regarding the production of flowers, Lavandula sp. did not manage to adapt and died 45 days after sowing and did not produce flowers. Spathiphyllum wallisii produced 12 flowers in RVG and nine flowers in PET, while Zantedeschia aethiopica produced 10 in RVG and 7 in PET. These results showed that the use of substrates made of RVG and PET is a viable alternative to be implemented in CWs. In addition, the reuse of PET is an option that decreases pollution by garbage. The plants Spathiphyllum wallisii and Zantedeschia aethiopica remarkably contribute in the removal of pollutants in wastewater. Additionally, the use of ornamental plants, with commercial interest such as those evaluated, enables an added value to the CW to be given, which can be used for flower production purposes on a larger scale and favor its acceptance within rural communities.

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.

Design Recommendations for Subsurface Flow Constructed Wetlands for Nitrification and Denitrification

1999 ◽  
Vol 40 (3) ◽  
pp. 257-263 ◽  
Author(s):  
Christoph Platzer
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Wastewater Treatment Plants ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Oxygen Balance ◽  
Vertical Flow ◽  
Soil Aeration ◽  
Return Rates ◽  
Nitrification And Denitrification

The paper presents a design for nitrogen removal in subsurface flow wetlands. The nitrification in the vertical-flow beds (VFBs) is clearly determined by the oxygen balance in the filter. Full nitrification can only be achieved when the oxygen balance is positive. For sizing purposes equations for the calculation of oxygen demand and oxygen input are given. Three possibilities to achieve sufficient soil aeration are presented and explained. For the denitrification two possibilities are presented. From technical wastewater treatment plants predenitrification is well known. Return rates up to 200% can be used without hydraulic problems for the VFBs. In cases of low C/N ratios an additional application of HFBs has to be used. The design can be carried out using a design of 1 g NO3-N/m2,d achieving a 65% removal in more than 90% of the cases. The paper discusses some of the equations presented internationally. The suitability of the use of k-values for the processes nitrification and denitrification is especially questioned.

Application of constructed wetlands for wastewater treatment in Nepal

2001 ◽  
Vol 44 (11-12) ◽  
pp. 381-386 ◽  
Author(s):  
R.R. Shrestha ◽  
R. Haberl ◽  
J. Laber ◽  
R. Manandhar ◽  
J. Mader
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Wastewater Treatment Plants ◽  
River System ◽  
Present Condition ◽  
Successful Implementation ◽  
Urban Centers ◽  
Untreated Wastewater ◽  
Under Construction

Surface water pollution is one of the serious environmental problems in urban centers in Nepal due to the discharge of untreated wastewater into the river-system, turning them into open sewers. Wastewater treatment plants are almost non-existent in the country except for a few in the Kathmandu Valley and even these are not functioning well. Successful implementation of a few constructed wetland systems within the past three years has attracted attention to this promising technology. A two-staged subsurface flow constructed wetland for hospital wastewater treatment and constructed wetlands for treatment of greywater and septage is now becoming a demonstration site of constructed wetland systems in Nepal. Beside these systems, five constructed wetlands have already been designed and some are under construction for the treatment of leachate and septage in Pokhara municipality, wastewater in Kathmandu University, two hospitals and a school. This paper discusses the present condition and treatment performance of constructed wetlands that are now in operation. Furthermore, the concept of the treatment wetlands under construction is also described here. With the present experience, several recommendations are pointed out for the promotion of this technology in the developing countries.

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