Water Reuse Criteria Research Articles

Development of novel high anti-pollution polyamide/polysulfate disk tubular reverse osmosis membrane modules and their application in simulated space bathing wastewater

Water is a precious resource in space stations, and wastewater recycling is necessary to meet the needs of astronauts. In that respect, applying the high anti-pollution disk tubular reverse osmosis (DTRO) technique is a reliable way to remove pollutes from wastewater. Thin film composite (TFC) membrane treatment is the most frequently employed solution for purifying wastewater in industry; however, the intrinsic weaknesses of polymer membrane substrates, e.g., poor mechanical property, foulant adsorption and low resistance to acidic/basic conditions, greatly hamper their applications. In this study, the novel polysulfate (PSE) membrane substrates were prepared via non-solvent induced phase separation (NIPS) method. The microstructure and performance of PSE membrane substrates were comprehensively investigated at varying polymer concentration and nanoparticle types. The results showed that adding nanosilver to the support layer significantly enhanced the TFC- PSE/Ag membrane performance (up to 57 %) and tensile strength (by 4.57 ± 0.13). According to computational fluid dynamics (CFD) simulations, the optimized geometric design of deflectors would have noticeably improved the flow field distribution and strength, which was consistent with experimental data. The DTRO modules enabled the effective management of wastewater using simulated space bathing wastewater. The effluent met the water reuse criteria in terms of COD concentration, NH3-N concentration, conductivity and turbidity whose respective values were 15 mg/L, 0.21 mg/L, 60 μS/cm, and 0.9 NTU. The proposed DTRO modules own antifouling and acid/alkaline-resistance, indicating their remarkable application potential in the large-scale recovery of bathing wastewater from the earth or space station.

The NEWgeneratorTM non-sewered sanitation system: Long-term field testing at an informal settlement community in eThekwini municipality, South Africa

Globally, there is a dire need for a new class of advanced non-sewered sanitation systems (NSSS) to provide onsite wastewater treatment that is capable of meeting stringent discharge or reuse criteria. These systems need to be simple to operate and maintain, reliable, and resilient to unreliable electrical service. The NEWgenerator (NG) is a compact, automated, solar-powered wastewater treatment system comprised of three major treatment processes: anaerobic membrane bioreactor (AnMBR), nutrient capture system (NCS) with ion exchange and carbon sorption, and electrochlorination (EC). The NG system operated at an informal settlement community in South Africa over a 534 d period, treating high-strength blackwater (BW) and yellow water (YW) from a public toilet facility. Over three test stages (BW, BW + YW, BW) that included several periods of dormancy, the NG system was able to provide a high level of removal of total suspended solids (97.6 ± 3.1%), chemical oxygen demand (94.5 ± 5.0%), turbidity (96.3 ± 9.7%), color (92.0 ± 10.5%), total nitrogen (82.1 ± 24.0%), total phosphorus (43.0 ± 22.1%), E. coli (7.4 ± 1.5 LRV, not detected in effluent), and helminth ova (not detected in effluent). The treatment levels met most of the ISO 30500 NSSS standard for liquid effluent and local water reuse criteria. A series of maintenance events were successfully conducted onsite over the 534 d field trial: two membrane cleanings, two NCS regenerations, and granular activated carbon replacement. Desludging, a major pain point for onsite sanitation systems, was unnecessary during the field trial and thereby not performed. The AnMBR performed well, removing 94.5 ± 5.0% of the influent COD across all three stages. The high COD removal rate is attributed to the sub-micron separation provided by the ultrafiltration membrane. The NCS was highly efficient at removing total nitrogen, residual COD and color, but the regeneration process was lengthy and is a topic of ongoing research. The EC provided effective disinfection, but frequent prolonged run cycles due to power supply and water quality issues upstream limited the overall system hydraulic throughput. This extended field trial under actual ambient conditions successfully demonstrated the feasibility of using advanced NSSS to address the global water and sanitation crises.

Faecal coliforms, faecal enterococci, <i>Salmonella</i> Typhi and <i>Acanthamoeba</i> spp. UV inactivation in three different biological effluents

Efficiency of UV-light to inactivate microbial indicators, Salmonella Typhi and Acanthamoeba spp. was studied in three different biological secondary effluents. Even though effluents differed in terms of their total suspended solids content, transmittance and particle size distribution, the UV-light dose required to fulfil WHO agricultural water reuse criteria was the same (30 mW·s/cm2), because the particle content with sizes > 40 µm was similar and very small. Using this dosage, 3 log of Salmonella Typhi and faecal enterococci were also inactivated. To avoid faecal coliform and Salmonella Typhi photoreactivation, the UV dose had to be doubled and in the process 2.5 log of Acanthamoeba spp. were also inactivated. This is interesting because its presence in wastewater, pathogenicity and resistance to conventional disinfection processes has been reported in the literature. Additionally, it was found that the faecal coliforms' inactivation rate constant was the lowest one of all the bacteria studied (Salmonella Typhi and faecal enterococci), suggesting the limitation of this indicator when several kinds of pathogens are present, as is the case in developing countries.

Assessment of the Viability of the Reuse of Sedibeng District Municipal Secondary Effluent in Southern Gauteng, South Africa

Population growth, urbanization, water resources pollution, environmental awareness, uneven distribution of water resources and water scarcity have necessitated water reuse especially in arid and semi-arid countries. Influent and effluent data of chemical and biological analyses from four wastewater treatment plants (WWTPs) in the Sedibeng district municipality (SDM) were used to assess the viability of water reuse. Available worldwide water reuse criteria of Water Reclamation Plants (WRPs) for different reuse options were used to characterize the SDM’s four WWTPs for potable water, power and steel industrial water reuse. Only WWTP4 does not meet the influent design criteria of the New Goreangab WRP in Windhoek, Namibia of 43 mg/l and the DWAF general limit of discharge of 75 mg/l used by Beaufort West WRP in South Africa for COD. WWTP2 and 4 do not meet the DWAF general limit of 25 mg/l for suspended solids. Some of the water quality parameters of the effluents from these plants were non-compliant to the requirements for reuse in power generation and steel manufacturing. However, the implementation of advance treatment technologies such as membrane or advanced oxidation processes (AOPs) as part of the treatment train in a potential WRP would address the water quality issues. Water reclamation of SDM effluent either through direct (DPR) or indirect potable (IPR) water reuse, power generation and steel manufacturing industry has the potential of reuse in the Southern Gauteng region. The success of the selected option would be depended on cost effectiveness, stakeholder commitment and public acceptance of the reuse strategy.

Effective reuse of electroplating rinse wastewater by combining calcined oyster shell powder with H2O2/UV process

In this study, the merits of combining the oyster shell powder (OSP) pre-treatment with H2O2/UV post-oxidation for the reuse of electroplating rinse wastewater were evaluated. The results showed that the calcined OSP was more effective in removing heavy metals than the original OSP. For the 1,000°C-calcined OSP of 0.6 g/L, the removals were 98, 94, and 99% for Fe, Ni, and Cr, respectively. That is, a small quantity of the calcined OSP could remove a large quantity of heavy metals due to the large specific surface area and the dramatically increased pH; the former resulted in a better adsorption capability and the latter induced buck precipitation. Further, after the post H2O2/UV process, the chemical oxygen demand and total organic carbon were reduced from 1,206 to 41.2 mg/L and from 252 to 12.6 mg/L, respectively, for pH of 8.0, H2O2 of 1,000 mg/L, UV of 52 W, and oxidation time of 240 min. That is, the combination of calcined OSP pre-treatment and H2O2/UV post-oxidation could not only treat the electroplating rinse wastewater to comply with the Taiwan’s effluent standard but could also satisfy the in-house water reuse criteria while resolving the issue of waste oyster shells simultaneously.

Effective Reuse of Electroplating Rinse Wastewater by Combining PAC with H2O2/UV Process.

This study evaluated the performance of treating electroplating rinse wastewater by powder activated carbon (PAC) adsorption, H2O2/UV oxidation, and their combination to remove organic compounds and heavy metals. The results showed that neither the process of PAC adsorption nor H2O2/UV oxidation could reduce COD to 100 mg/L, as enforced by the Taiwan Environmental Protection Agency. On the other hand, the water sample treated by the combined approach of using PAC (5 g/L) pre-adsorption and H2O2/UV post-oxidation (UV of 64 W, H2O2 of 100 mg/L, oxidation time of 90 min), COD and DOC were reduced to 8.2 mg/L and 3.8 mg/L, respectively. Also, the combined approach reduced heavy metals to meet the effluent standards and to satisfy the in-house water reuse criteria for the electroplating factory. The reaction constant analysis indicated that the reaction proceeded much more rapidly for the combined process. Hence, it is a more efficient, economic and environmentally friendly process.

Water Reuse in EU States: Necessity for Uniform Criteria to Mitigate Human and Environmental Risks

Water quality criteria are an indispensable part of water reuse projects aiming to ensure the protection of public health and the environment. In addition, criteria can affect the development, public acceptance, and economic viability of water reuse projects. Currently no uniform criteria exist, but they diverge, often greatly, between countries and states. The authors briefly present the evolution of reuse criteria worldwide and discuss emerging issues related to ecological and public health risks that have not addressed adequately in existing criteria. They specifically focus on European Union (EU) countries and present their water reuse status based on the published data and the existing (or nonexisting) reuse frameworks. Data gathered from public agencies reveal a high potential for water reuse in the EU that could potentially contribute to ensuring that fresh water is available for all sectors and to protect the environment, but it has not expanded at the expected rates. The lack of water reuse criteria was thought as the most important cause for this delay. lasting recent years, however, several countries, particularly those located in the Mediterranean basin, established water reuse criteria. Similarities and differences as well as potential benefits and drawbacks of these criteria are discussed and interpreted with these of the other world. An important conclusion is that the criteria enacted in Greece, Italy, and Spain will probably prevent the development of water reuse projects and increase the costs. Moreover, major challenges, the future views, and the necessity for establishing common regulations for water reuse at an EU level are considered.

Evaluation of UV/H2O2 for the disinfection and treatment of municipal secondary effluents for water reuse

AbstractBACKGROUNDIn this work, photochemical treatment (UV/H2O2) of a municipal secondary effluent was studied to assess its suitability for preparing water for reuse. Ten water reuse criteria obtained from the legislation of eight countries were used as indicators of water quality. Effluents from the municipal wastewater treatment plant (WWTP) of Gavà‐Viladecans (Barcelona, Spain) were subjected to UV/H2O2 treatment with low H2O2 concentration ([H2O2]o = 5 mg L−1 and UV fluence = 8.04 mW cm−2) and the most common water reuse parameters, such as disinfection indicators, turbidity, total suspended solids and microcontaminant removal (atrazine), were monitored.RESULTSTreatment inactivated 100% of the disinfection indicators after 5 min. Afterwards, three levels of treatment corresponding to different reuse applications were defined according to the legislation used. In addition, according to the LuminoTox® bioassay, oxidative treatment of the secondary effluent favoured the formation of less toxic intermediates. Finally, a study was performed to determine the costs of each reuse condition.CONCLUSIONSFindings suggest that UV/H2O2 is a suitable method to obtain water of sufficient quality for further reuse. © 2012 Society of Chemical Industry

A strategic plan for reuse of treated municipal wastewater for crop irrigation on the Island of Crete

► A methodology for planning water recycling on islands is presented. ► It is a tool to incorporate reclaimed water in the water management of islands. ► Reclaimed wastewater quantities are matched against specific irrigation needs. ► The exploitation of this water resource can relieve water stress in islands. This work presents a strategic plan on the feasibility of recycling treated municipal wastewater for agricultural irrigation on the Greek island of Crete. Three types of crops were investigated, namely olive trees, vineyards and lettuce as representative of raw-eaten vegetables. The Greek water reuse criteria were used as guidelines for the irrigation of the above mentioned types of crops. Qualitative and quantitative data regarding wastewater plant effluents were collected from 16 wastewater treatment plants (WWTPs) operated on Crete. Analysis of the collected data indicated that WWTPs did not meet the criteria for unrestricted irrigation of the crops, due to absence of tertiary treatment . In order to estimate the area of land that can be irrigated using treated effluents, the water requirements of each crop were estimated as the difference between evapotranspiration and effective precipitation using climatic data as input to CROPWAT software. Based on WWTPs capacity, the irrigated area was estimated and then was visualized and demonstrated using the CORINE 2000 database in ArcGIS. The present study showed that water recycling during summer could reserve approximately 19.16 Mm 3 of fresh water, which corresponds to 4.3% of total irrigation requirements . It is evident that the exploitation of this alternative water resource could be beneficial for Crete, relieving island's water shortage and stress.

Comparison and modeling of two biofilm processes applied to decentralized wastewater treatment

In order to control water pollution in the rapidly urbanizing South China area, biological contact oxidation (BCO) process and biological aerated filter (BAF) process were applied in a pilot-scale experiment for decentralized wastewater treatment. An investigation to find the optimal parameters of the two biofilm systems was conducted on hydraulic loading, organic loading, and aeration rate. The results indicated that the water reuse criteria required a maximum hydraulic and organic loading of 30.0 m3/(m2·d) and 4.0 kg COD/(m3·d), respectively, as well as a minimum effluent DO of 4.0 mg/L. The utilization of a new media allowed BAF to perform better than BCO. The kinetic description of the COD removal process for BAF and BCO are S e = S 0e−0.639t /(1 + 1.035t), and S e = S 0/[(1 + 0.947t)(1 + 1.242t)], respectively. The correlativity analysis showed that the two models could predict the effluent water quality based on the hydraulic retention time. Thus, the appropriate hydraulic loading for certain effluent water quality demands could be determined. The two models could be applied to wastewater treatment practice.

Evaluation for the Reclamation Potential of High-Tech Industrial Wastewater Effluent Treated with Different Membrane Processes

Due to the shortage of water supplies, the reclamation and reuse of the effluents from wastewater treatment plants has become an important issue in Taiwan, especially for industrial parks. By constructing a reclaimed water distribution system, the reclaimed water could be used as nonpotable and industrial water. This research used three advanced integrated treatment processes, including sand filtration (SF), microfiltration (MF), granular activated carbon (GAC), ion exchange (IE), reverse osmosis (RO), and an ultraviolet disinfection (UV) unit, to treat the effluent from the wastewater treatment plant of Hsin-Chu Science-Based Industrial Park. The reclamation potential of treated water was examined compared with different water reuse criteria. The results of the experiments showed that different process could achieve different levels of water purification. This was dependent on the complexity and sequence of the units. The effluent from the simplest process, called process A, which combined the SF, MF, GAC, and UV units in that order, could meet the criteria of nonindustrial water. The effluent of process B and C, which additionally installed IE–MF–RO and MF–RO–IE units in sequence, respectively, between the GAC and UV units of process A, could be reused as sprinkling, landscaping and recreational water; cooling-system makeup water; low-pressure boiler feed water; as well as potable water or Newater with suitable advanced treatment.

Water reuse criteria in the United States

Water reuse is well established in the United States, with uses ranging from pasture irrigation using reclaimed water that has received a low level of treatment, to augmentation of potable water supplies with highly treated reclaimed water. There are no federal regulations governing water reuse and criteria are developed at the state level. Criteria differ between states that have adopted regulations or guidelines, but criteria among states where water reuse is prevalent are similar and tend to be conservative, with public health protection being the most important consideration. The US Environmental Protection Agency (EPA) has published guidelines for water reuse that include recommended criteria for various reclaimed water applications.