Best Practices Resource Recovery from Water

Learning from Best Practices on Resource Recovery from Water

Driven by environmental, economic, and ecological benefits, resource recovery from waste has started to draw attention worldwide. Recovering resources from water and wastewater can provide an alternative and economically viable source of resources supporting the resilience of human and natural systems under water stress. Resources from the water cycle can be water itself, energy (organic or thermal) and components such as nutrients and metals.

A range of new initiatives are underway to promote and accelerate the development and uptake of resource recovery science and technologies. Innovation on resource recovery in the water cycle has been developing fast, but examples of large scale and marketable applications from current scientific innovations are scarce. The key issue here is how to move from research to practice, while also taking into account: a. the market potential for the resource recovered, b. appropriate public policy, regulation and institutional arrangements to support and accelerate resource recovery and c. stakeholders’ needs well integrated with technologies, markets, policy, new initiatives, current research and practice.

A best practice, in this case, is a proven technology on resource recovery, applied at full scale, from supply to demand, which can serve as an excellent example for another country, area, company, etc.

This web-based tool shows best practices on resource recovery from water. The goal is to share and exchange knowledge and experience, with the ultimate goal to learn from best practices and make new innovations on resource recovery possible.

IWA Resource Recovery Cluster aims to bring together R&D, water industry and materials users, and to promote economically and environmentally attractive approaches to resource recovery.

Roest-Kees-001-255x255

Contact

Kees Roest
Senior scientific researcher
+31 (0)30-6069531
Kees.Roest@kwrwater.nl 

Best Practices

WATER

This category shows best practices from water reuse, both industrial and potable water reuse.

[new] Integrated water recovery and reuse in a metal finishing industry.

FACTSHEET

Country: Turkey, Merkez/Bolu
Sector: Industry
Loads:  The water requirement for paint processes was able to be reduced by 50%, from 105.544 m3/year to 53.714 m3/year.

Summary

Bolu Cooking Appliances is a metal finishing factory located in Bolu, Turkey. The factory is one of the biggest white goods manufacturers in Turkey. The number of the staff working in the factory is 2,200 with an annual production capacity of 2,879,278 pieces of cookers. Detailed analyses (i.e., characterization, process profiles, pollution profiles, treatability) (1-4) were performed in terms of the determination of the applicability of the industrial process wastewater reuse considering all water consumption in the factory. In the light of these findings, the industrial process water reuse best practice technology using membrane technics was performed with the painting process wastewater of the factory.

Technology

In the process, integrated membrane process system was applied for water recovery to be reused in “paint shop” unit of the plant. Briefly,

  • the effluents generated from batch operation were collected by wastewater collection lines. the water is equalized in order to balance variable inflow.
  • the recovery system has [1] activated carbon filter [2] Ultrafiltration, UF unit [3] First stage Reverse Osmosis (RO) and [4] Second Stage RO Systems. Each unit has its own PLC system.
  • the system is automatically monitored by online conductivity, pH and pressure sensors. It was operated by SCADA system and fully automated depending upon requirement of water of the production.
  • the concentrate is channeled to industrial wastewater treatment plant
  • pressure differences and fluxes across the membranes are recorded online and appropriate chemical cleaning is activated using CIP systems.

The recycled wastewater should have a conductivity level below 150 μS/cm to be used in process free of color and TOC. In addition, the continuous supply of water to the process is compelled. The outlet (reused water) is again balanced in an equalization tank. The process withdraws reused water depending upon the hourly requirement. The SCADA system of water supply unit is integrated in the control system of the production. Reused water is distributed to the production area with piping system.

Stakeholders

Industry: ARCELIK Corporation, Bolu Province, Turkey, Owen Production Plant (www.arcelik.com)

Provider: İstanbul Technical University (ITU), Environmental Engineering Department provided the technology for recovery and reuse system.

Financial impact

The annual operating cost for water were reduced from € 48.130,-   to € 25.400,- . With the water usage fee of 0.13 €/m3, payback time is 5.3 years. However, if the water usage fee would rise to 0.26 €/m3, payback time will decrease to 3.5 years

Environmental impact

Water conservation and reuse strategies should be implemented in every sectors of life to achieve reductions in energy and greenhouse gas emissions. Investigation of water reuse strategies in industrial sectors can achieve energy savings and substantially can reduce carbon emissions. In the present case, the total energy savings potential of adapted strategies to the factory was assessed. By employing the reuse strategy to the factory, 51,830 m3/year wastewater flow could be reused and this would save approximately 4,095 kWh of electricity annually. Additionally, approximately 2.9 metric tons of CO2 emissions could be avoided.

Additional reference used:

[1] G. Insel, E. Ubay Cokgor, T. Olmez-Hanci, D. Okutman-Tas, F. Germirli Babuna, E. Gumuslu, G. Yuksek, N. Sayi-Ucar, G. Ozyildiz, N. Dizge, Water Reuse, Minimization and Integrated Water Management on Cooking Appliances Manufacturing, Final Report, The Scientific and Technological Research Council of Turkey (TUBITAK), Technology and Innovation Funding Programs Directorate, 2016.

[2] G. Insel, E. Gumuslu, G. Yuksek, N. Sayi-Ucar, E. Ubay Cokgor, T. Olmez-Hanci, D. Okutman-Tas, F. Germirli Babuna, D. Firat Ertem, Y. Okmen, Evaluation of water reuse in a metal finishing industry, Fresenius Environmental Bulletin, 26 (2017) 421-425.

[3] G. Insel, E. Gumuslu, G. Yuksek, N. Sayi-Ucar, E. Ubay Cokgor, T. Olmez-Hanci, D. Okutman-Tas, F. Germirli Babuna, D. Firat Ertem, O. Yildirim, Assessment of wastewater reuse potential for an enamel coating industry, World Academy of Science, Engineering and Technology, International Journal of Environmental, Chemical, Ecological, Geological and Geophysical Engineering, 10 (2016) 311-314.

[4] G. Insel, E. Gumuslu, T. Olmez-Hanci, F. Germirli Babuna, D. Okutman-Tas, E. Ubay Cokgor, G. Yuksek, N. Sayi-Ucar, G. Ozyildiz, N. Dizge, D. Firat Ertem, Y. Okmen, O. Erturan, B. Kirci, Water reuse in the metal finishing industry: Current situation and challenges, Journal of Membrane Science (in preparation).

[new] Bioloos – Sustainable Sanitation and Water Recovery in India

FACTSHEET

Country: India,  Hyderabad
Sector: Sanitation
Loads:  not specified

Summary

Bio-toilets (or bioloos) treat human waste using bacterial culture in a specialized bio-digester tank; and leaves out pathogen-free water that’s good for gardening and agriculture. No energy is required in the treatment process.

Technology

Bio-digester is a consortium of anaerobic bacteria that have been screened and gradually adapted to work at temperatures as low as -5°C through the isolation of psychrophilic bacteria from Antarctica/Siachen. These act as inoculums (seed material) to the bio-digesters and convert the organic waste into methane and CO2. The anaerobic process inactivates the pathogens responsible for water-borne diseases. Bio-digesters serve as reaction vessels for bio-methanation and provide anaerobic conditions and the required temperature for the bacteria.

Stakeholders

Supplier: Banka BioLoo in Hyderabad India

They work with other organizations and companies in implementing the system-solution. For instances, they partner with some large companies and implement the system in hundreds of schools

Financial impact

The bio-digester system is very cost-effective. Users don’t have to bear any cost in the future, compared to other sanitation systems. No separate disposal, transportation and treatment are required. The system obviates the need for external sewage infrastructure. The government doesn’t have to invest anywhere.

Environmental impact

The resource recovery system is environmentally-friendly; doesn’t need energy for treatment. No separate disposal is required, neither any transportation. All treatment takes places, anaerobically, within the bio-digester tank. It contributes to circular economy by providing usable water. The social impact has been immense. Thousands of users have access to toilets and sanitation. The systems deployed in railroads has ensured fecal-matter-free environment for millions of poor families staying close to rail tracks.

Orange Water County District – groundwater replenishment system

FACTSHEET

Country: USA, Orange County
Sector: Waste, ground and drinking water
Loads: 265,000 m3/day

Short Description

Wastewater effluent is being purified in the Advanced Water Purification Facility, where it is discharged into groundwater aquifers to later on be used as drinking water for residents in the surrounding area.

Technology

The AWPF uses a three-step purification process which includes microfiltration, reverse osmosis (RO) and a combination of ultraviolet light and hydrogen peroxide. The microfiltration is a low-pressure filter that sieves out bacteria and protozoa while the RO remove dissolved minerals and pharmaceuticals. The last step with UV-light destroys potential harmful constituents through penetrating cell walls of organisms and thus inducing cell death. The addition of hydrogen peroxide results in oxidizing organic compounds for ultimate removal from water. Calcium hydroxide, which is hydrated lime in powder form is added along with cationic polymers to stabilize and buffer the final product water.

One advancement that the GWRS beholds is the seawater intrusion barrier (see Figure 4.3) (Lenker et al, 2014). As more water is being pumped out of the basin, the risks of salt water seeping into the basin increases (GWRS, 2013). 114,000 m3/day out of the 265,000 m3/day that is being produced is pumped into injection wells where it is serves as a barrier for seawater. The rest of the water is distributed to percolation ponds designed for the water to pass through gravel and sand beds before augmenting the principal drinking water supply aquifer. The groundwater is later pumped to over 400 wells used by cities, local water agencies and other groundwater users.

Stakeholders

Orange County Water District (OCWD): The Orange County Water District (OCWD) was formed in 1933 and serves more than 2.3 million residents in Orange County [5]. It came about as an act of the California State Legislature and is responsible for managing and protecting groundwater basins in Orange County.

Orange County Sanitation District (OCSD): OCSD purifies secondary effluent. Together with Orange County Sanitation District (OCSD), OCWD has developed a Groundwater Replenishment System (GWRS). The system began operations in January 2008 and the GWRS is today the world’s largest used water purification system for indirect potable reuse (Chalmers and Patel, 2013).Their treatment facility, known as the Advanced Water Purification Facility (AWPF), discharges treated water into groundwater aquifers to later on be used as drinking water for residents in the surrounding area.

In regards to social aspects, the District made noteworthy efforts in gaining public acceptance which has resulted in the community’s approval of the project. The public outreach program began already in 1997, years before the system was designed, to educate people about the positive aspects of water reuse.

Financial impact

The Factory was also the first in the world to perform advanced treatment of used water for injection into coastal drinking water aquifers.

Environmental impact

There was a demand to increase the available pool of water, to decrease the demand of the imported water as well as a prevent seawater intrusion.

Source: IWA Resource Recovery Cluster Compendium (to be published, 2014)

Water reuse at Yatala brewery

FACTSHEET

Country: Australia, Queensland
Sector: Industrial water
Loads: Annual recycled water 420 ML of 820 ML annual municipal water consumption

Summary

With a beer production capacity of 450 ML/yr, Carlton United Breweries (CUB) at Yatala, south of Brisbane, is one of the largest breweries in the country. Using 2.4 L water/L beer, it is leading the way internationally in demonstrating world best practice water consumption. Historically this ratio was around 7-10L water/L beer, and internationally, the average is currently 3-6L water/L beer.

Technology

Advanced Water Treatment – Anaerobic + Aerobic biological treatment followed by Micro filtration, Reverse Osmosis , advanced oxidation and chlorination.

Internal optimisation of all water usages.

Stakeholders

Gold Coast City Council; Research sector; Policy makers; Public.

Risks to reputation of business from public misconceptions – recycled water does not contact product. Long term ongoing emphasis on training and awareness at all levels. Biggest barrier is perceptions attached to consumption of treated water. The final product from our plant is superior in all parameters to reticulated supply. Yuk factor still applies however. World needs to grow up.

Financial impact

Project costs for overall plant spread over 20 year period and justifications mixed from stay in business through environmental and economic benefits. As recycling costs compensated by reductions in municipal headworks charges this is more complex.

Environmental impact

Reduction in carbon footprint related to on site anaerobic waste treatment against municipal aerobic treatment. Untreated waste equivalent to approximately 200,000 EP. Net gain in energy from biogas generation.

Additional reference used: waterrecyclinginvestment.com

ENERGY

This category shows best practices on energy recovery from the water cycle. This can be thermal energy, e.g. out of the sewer. Or a case on energy neutral/positive wastewater treatment.

[new] Maynilad Energy management System

FACTSHEET

Country: The Philippines, Quezon City
Sector: Drinking water production and distribution; domestic-quality wastewater treatment
Loads: Total CO2-e emission reduction over the period June 2015 to December 2016 (1 year and 7 months) is 1,192.03 tons CO2e.

Summary

Maynilad has been tracking its carbon footprint since 2009 and consistently find that the highest contributor to its carbon emissions are indirect emissions from purchased electricity and fuel ( 90%). This is due to the fact that they have to use energy intensive technologies to produce drinking water. As part of its continued efforts towards achieving operational efficiency, Maynilad wanted to assess and implement ways by which it can reduce its energy consumption. The end-goal was to sustain water and wastewater service expansion while producing less carbon dioxide.

Technology

Savings generated during the implementation of the Energy Management System is mostly behavioral/procedural changes (with no capital costs). Reduction in operating hours of rapid mixers during low turbidity of raw water input in the La Mesa Treatment Plant 1 and the reduced scour air operation in the La Mesa Treatment Plant 2 are some examples of controls done by the significant energy users. The reduction in operating hours ensured that energy consumption is reduced during normal conditions without affecting the quality of the product water

Members of the EnMS Core Team received technical training and assistance from the United Nations Industrial Development Organization (UNIDO) - Department of Energy (DOE) EnMS National Experts of Accelence Consulting, Inc. as part of the establishment and implementation of the EnMS.

Stakeholders

Maynilad Water Services, Inc.

In the initial stage of establishing its Energy Management System (EnMS), the company tapped the services of an external consultant, Accelence Consultancy Inc. whose lead consultant is among the first batch of UNIDO-trained EnMS experts in the Philippines. The company also has a close coordination with the Department of Energy (DOE) which is the executive department of the Philippine Government responsible for all programs and projects of the Government relative to energy exploration, development, utilization, distribution and conservation.

Financial impact

Total energy cost savings on EnMS implementation over the covered period is $USD 301,253 with a payback period of 0.113 years (equivalent to 1.4 months).

Environmental impact

Plant for Life. 21,287.16 tons of carbon is stocked or captured in the plant biomass and soil instead of being released to the atmosphere as CO2. 4,247.91 tons CO2 is sequestered or absorbed from the atmosphere and used for mangrove plant growth instead of contributing to the global GHG. These figures will continue to rise as the mangroves grow through the years.

For EnMS Reduction in Carbon Footprint due to less energy/power usage. During the documentation stage of the EnMS, the core team was able to review and rationalize existing procedures in the facilities. Evaluation of existing procedures has led to the team realizing there are still plenty of opportunities for energy savings simply by optimization of equipment operation. Each site energy manager is tasked to monitor the daily energy performance of their facility and reporting the results on a monthly basis to the management. This is part of our procedure on monitoring and measuring of Quality, Environment, Energy, Safety and Health (QESH) Performance. In addition, the opportunities for improvement established by each site energy managers are measured to specifically quantify the impact of each activity.

[new] Guia’s WWTP 0% - 100% Energy Self-sufficient

FACTSHEET

Country: Portugal, Lisboa
Sector: Sewage water treatment
Loads:  Energy neutrality resulting in a reduction of 6,000 metric tons CO2 equivalent/year

 

Summary

Guia's Wastewater Treatment Plant (WWTP) one of EPAL main assets, is the largest Portuguese WWTP and one of the main engineering works in Portugal due to the complexity of its technical solution, the requirements of the receiving environment (bathing area) and urban planning (tourist zone).

The main operating cost of water cycle management entities is associated with energy consumption. In Portugal this sector is responsible for about 2% of the energy consumed in the country. The trend towards increasing energy costs and the fact that the urban water cycle sector has increased responsibilities in reducing greenhouse gas emissions have led to the implementation of an Energy Management System (EMS) and subsequent certification by an external entity. For Guia’s WWTP, the EMS encompassed an even more ambitious objective: to ensure that this WWTP is constituted as the first Portuguese Energy self-sufficient WWTP - and one of the first in the world of this magnitude - thus representing a benchmark for the sector and boosting projects inside AdP – Águas de Portugal group and in other management entities.

Technology

By a mesophilic digestion of primary sludge removed from the wastewater it is possible to produce biogas (60-65% methane) in a ratio of 21 m3 biogas produced/m3 sludge feed to digester), the biogas is used as fuel in cogeneration to produce electricity consumed at the WWTP. EMS and ISO 50001 certification results in an optimization of all process stages that allow reducing energy consumption all over the (facility) treatment process of wastewater but also in other areas as odor control, lighting, etc.

All implemented measures (process, procedures, training, etc.) enhanced on reducing the energy consumption and simultaneously promote the amount of biogas produced in the digestion process and subsequently the amount of energy produced.

The methodology adopted at Guia’s WWTP can be easily implemented in another WWTP to achieve similar levels of energy efficiency without significant amount of investment.

Stakeholders

Guia’s WWTP serves about 800,000 inhabitants and treats 55 million m3/year of wastewater, serving 4 municipalities in an area of 220 km2 by Lisbon metropolitan area.

EPAL - Empresa Portuguesa das Águas Livres, S.A. is the successor of the centenary CAL - Companhia das Águas de Lisboa, a water supply concessionaire to the city of Lisbon

Financial impact

The "Guia’s WWTP 0% - 100% Energy Self-sufficient” project started in February of 2016, leading to the public announcement that the WWTP is 100% self-sufficient in energy consumption in January of 2017. Due to a cogeneration system based on the use of the calorific value of biogas produced by the anaerobic sludge digestion to produce electric energy, as well as to the implementation of other measures, this WWTP changed from an intensive external energy consumer to an energy self-sufficient one. The total energy produced at the facility has an annual market value of about € 1,004,570. In 2016 the revenue from treated wastewater at Guia’s WWTP was about € 2,000,000.

All measures already implemented and those that will be implemented have a return period of less than four years, being primarily operations management measures, with a strong commitment to operational planning and control. It was proven with this project that the economic constraints, in times of scarce resources, can be overcome by a commitment to planning and operational control based on the competence of human resources.

Environmental impact

The environmental results are evident, through the energy neutrality achieved, ensuring a reduction of around 6,000 metric tons CO2 equivalent/year.

Energy and phosphorus recovery from potato wastewater

FACTSHEET

Country the Netherlands
Sector Industry wastewater
Loads 3 million m3 biogas and 1500 kg struvite/d

 

Treatment plant

Wastewater from potato industry is treated anaerobically and energy and phosphorus is recovered. Recently the struvite is blended and turned into the product ‘Vitalphos’.

The construction of the plant (phospaq and anammox) was completed in 2006. The 3 UASB reactors have been in function since 1982. Before 2006 the Aviko wastewater was only treated anaerobically and turned to the municipal treatment plant.

Vitalphos plant started up in 2014, in the Vitalphos plant the struvite is upgraded to a fertilizer by drying the struvite and adding various natural materials.

Technology

  • Anaerobic digestion for energy recovery
  • Biological biogas scrubber for sulfur recovery (ThioPaq)
  • Struvite precipitation for phosphorus recovery (PhosPaq)
  • Production of Vitalphos from the struvite: drying and blending with various natural materials, custom made (Marathon organic buffer complex, patented)
  • Anammox for N removal

Stakeholders

The struvite recovery is in use since 2006. A lot of experience is gained since the start up. Good operational knowledge is needed for successful struvite recovery, this also counts for the Vitalphos plant.

Crucial was the involvement of an agricultural and retailer expert.

Financial impact

The Industry pays for the treatment of the wastewater (imposed in the wastewater discharge permit) by outsourcing this activity to another company (Waterstromen).

The cost/benefit analysis is very specific for the local situation. Nothing can be said about this.

Waterstromen

Waterstromen owns and operates several wastewater treatment plants.

Dried pellets using warmth from engine during transport


FACTSHEET

Country the Netherlands
Sector Drinking water
Loads 10-15% is dried in 2014

 

 

 

Description

Softening pellets are the by-product of the softening of drinking water. Until recently, there pellets were sold without any processing like drying, grinding and/or sieving. In other words, the pellets were brought to the market supply driven, not demand driven.

However, with an ambition to valorise the softening pellets further, it seems unavoidable to process the pellets in order to meet specifications of potential appliers of the material. One of the major challenges in this case is to find an application with the highest added value (environmental, financial) with the lowest processing efforts.

Some customers want to pellets to be delivered ‘dry’, whereas they normally have a moisture content of 3-4%. They want them dry, for example because wet pellets cost more energy in thermal processes of because the wet pellets stick together and cause clotting.

However, the processing step ‘drying’ is expensive (storage wet, drying process, storage dried, extra transport) and is not environmental friendly because of the energy use. About a year of research resulted in a relative simple answer to these challenges: drying on board of the truck with the warmth from the engine. It is cost effective, because there is no need for storage and extra transports. The warmth from the engine would have been emitted to the air, so using this warmth makes the use of (extra) fossil resources unnecessary.

Since April 2013 several customers are supplied with dried pellets, giving the pellets an higher economic value and making higher grade applications possible.

Technology

Shared service centre Reststoffenunie and SME Van Lijssel took the initiative to develop a truck where the pellets can effectively be dried on board with the warmth from the engine. The technical challenge was mainly to get this warmth evenly spread over the load in the truck. About 10-15% of the available pellets in the Netherlands are dried on board of a truck in 2014. The moisture content is lowered from 3-4% at loading to < 1% delivered at the client.

The production plants didn’t have to make any (technical) adjustment. Evidently, the moisture content at the moment of loading has an impact on the duration of the drying process. Therefore, agreements have been made with these production plants to hold the purging of water some hours before loading the pellets.

Stakeholders

  • Buyers: Wanting a secure supply of dried pellets. They were asked to give commitment
  • Transport company: Invested in trailer & truck. Brought in knowledge:
  • Research company: Studied the possibilities and advised the adjustments of the trailer.
  • Suppliers: commitment on supplying for a longer period of time, guaranties on the moisture content of the pellets.

Financial impact

The adjustment of the trailer cost some 40-50 k€, the research excluded. The added value of the dried pellets resulted in a payback time of less than 1 year. Essential is, however, that the truck is fully engaged with the transport of softening pellets. Cleaning because of the transport of other material (cost, contamination risk) or standstill (cost) is not an option.

The research costs were 50-75k€, the adjustment of the trailer 40-50 k€. The research costs on other softening pellets will be much smaller, most is known. For other materials new research is needed, the drying process is evidently dependent on the material that must be dried.

Environmental impact

The obvious hypothesis is that this impact is positive: high grade application become possible and almost no extra resources (like fossil fuels) are needed.

Main risks are:

  • The truck must be able to drive (and dry) 5 days a week. Not fully booked, the costs will rise;
  • At the beginning, the process will start with one truck. If this truck fails, there is no backup;
  • The pellets may differ in grain size. Size distribution has an impact on the drying process (the smaller they are, the more difficult it is to dry them;
  • The shorter the distance between source and destination, the shorter the time is to dry the pellets. If the distance is too short, the pellets will be dried as the truck stops with warmth from an aggregate. Still financial valid, but less on the environmental aspects.

Reststoffenunie

Drinking water sector established RU as a shared service centre for the sector to ‘market’ the residuals. Combining knowledge, buying- and selling-power and innovation was the main reason to work together. The moment the residuals leave the production site, RU becomes owner of these materials.

Energy positive wastewater treatment at WWTP Strass, Austria


FACTSHEET

Country Austria
Sector Municipal wastewater
Loads 90.000 - 250.000 p.e.; 43 L Biogas / p.e.

 

 

Treatment plant

WWTP Strass treats municipal wastewater with a small proportion of industrial wastewater (less than 10%). It is a rural area and the load varies due to tourism from 90.000 – 250.000 p.e. It started up in 1989 and process modifications, retrofits and control improvements were implemented to achieve energy positive wastewater treatment. Effluent requirements are 5 mg/l Ammonia –N daily average and 1 mg total P daily average; 70% N removal annual average. The plant consumes 23 kWh/PE/a. No external sludges are treated, but food waste is added as co-substrates (10% of the TS load to the digestor). The digested sludge is partly composted, partly incinerated.

Technology

Several measures and new technology implementation has resulted in the energy positive treatment:

  • Two-sludge system (high rate BOD removal followed by nitrification/denitrification) moving to mainstream deammonification.
  • Reduction of chemical costs for sludge thickening by 50% by switching from mechanical thickening to gravity thickening for biological sludge.
  • Reduction in sludge dewatering costs by 33% by switching from Ca/Fe conditioning to Polymer.
  • Reduction in energy consumption for sidestream treatment from 350 kwh/d to 196 kwh/d by implementing a novel sidestream nitrogen removal system (DEMON®).
  • Initially using primary sludge as a carbon source for sidestream treatment, since implementation of DEMON all organics are fed to digester. Total electrical energy benefit of ca. 15% by DEMON.
  • Enhanced utilization of the digester gas by converting to a state-of-the-art cogeneration unit, boosting electrical efficiency from 33% to 40% and overall usage efficiency from 2.05 to 2.30 kwh/m3 of digester gas.

Energy positive wastewater treatment at WWTP Strass, Austria

Stakeholders

There are no regulatory requirements for energy positive wastewater treatment. Cost optimization effort and benchmark comparison with other plants in Austria are done.

Trade- and craft skills of all employees involved were of high level. There was a close cooperation with research institutes, universities and other utilities.

Low revenue from electricity sales led to contract with natural gas supply company. Feeding 10 % (without co-substrates) to 80% (with co-substrates) of the electricity power back to the grid.

There is no compensation for taking over food wastes which led to reduction in co-digestion.

Barriers/bottlenecks were limited financial incentive and limited work force.

Financial impact

  • Pay-back time of all investments was 5 – 7 years.
  • 0.12 Euro/kWh for purchase from the grid;
  • 0.05 Euro/kWh sold to the grid
  • Risks were minimized by large inkind contributions.

Environmental impact

Studies were done but were not crucial for decision making.

COMPONENTS

This category shows best practices on recovery of components from water, e.g. iron sludge recovery from drinking water production and struvite production from wastewater.

[new] Integrated Fat, oil and grease waste recycling program under PPP Model to improve the performance of sewer networks/pumping stations/treatment plants in emirate of Dubai

FACTSHEET

Country: UAE, Dubai
Sector: Sanitation
Loads:  12 million gallons of grease is being collected and processed in a recycling facility annually

Summary

Thousands (about 17000) of restaurants and hotels in Dubai process food in large quantities and an equal amount of Fat, oil and grease (FOG) waste is dumped down the drains. Fats, oils and grease cause major problems to drains and sewers. These FOG blockages can result in sewer flooding, odour problems and the risk of rat infestations, both near and beyond the premises. In fact, every outlet disposing of fat, oil and grease into sinks and drains is at risk of experiencing damaging and costly drainage problems. In order to overcome this issue, Dubai municipality and M/s Al Serkal group established a waste edible oil recycling facility at Al Awir on Built , Operate and Transfer Contract (BOOT) basis which recycles the waste cooking oil from hotels, restaurants and food processing industries. The waste that is taken to the plant from the hotels /restaurants goes into process and produces soil, water and oil that can be reused for composting, irrigation and cosmetic industries respectively. The hotels , restaurants and food service establishments are responsible for collection of FOG deposited in the grease traps and transport through authorized logistics company to the Al Awir processing plant. Also It will be interesting to note that in this successful PPP model project, about 12 million gallons of grease is being collected and processed in the recycling facility annually.

Technology

Grease traps act as interceptors when installed under the kitchen sink screening and retaining oil, grease and food wastes in the form of solids and only allowing the waste liquid to flow through thus ensuring no blockages are caused. Grease traps (also known as grease interceptors, grease recovery devices and grease converters) are plumbing devices designed to intercept most greases and solids before they enter a wastewater disposal system. The raw waste from grease trap is collected and disposed at the facility and filtered in a 2 mm filter and passed through grinder, then collected in storage silo equipped with heating coils and isolated with thermal isolation or jacket. The material is kept at temperature in the tank to melting points of Fat, Oil and Grease so that preseparation starts. The feed pump, installed on the decanter skid, takes the product from the bottom and pump it to decanter for the solid separation. From the de- canter, solids are discharged by gravity and a conveyer allows the disposal in a dedicated movable skip. The separated liquid (oil + water) flows by gravity from the decanter and is then pumped into a second tank isolated by jacket to keep at process temperature. The grease trap waste (input) fed to the separator is separated into 3 different streams as by products:

  1. Clean Oil (by product sold to cosmetic industries)
  2. Water (useful for irrigation)
  3. Sediment (sludge-for composting)

The quality of the process is controlled by the operator by monitoring “Plant Process Control Panel” and also visually through appropriate sample point and inspection devices. The two liquid phases, oil and water are pumped by means of built in centrifugal pump to dedicated tanks and the solids that are discontinuously discharged will flow into an another receiving tank. The Oil collected in storage tank is sold to the customers( cosmetic industries) and the water is sent to Dubai municipality’s Sewage treatment plant.

Stakeholders

Problem owner: Dubai municipality

Technology supplier: M/s Al Serkal Environmental group

The project committee is headed by the Director – sewerage and irrigation network department and the committee is composed of senior level officials from various departments and sections/units of the Dubai municipality.

The Dubai municipality introduced a permitting system to stream line the collection of grease waste from the food service establishments. 38 private companies are approved to collect the grease waste from the hotels. About 60 vehicles are deployed and in order to control the illegal dumping by hauling companies, Dubai municipality advised the installation of GPS devices in all vehicles.

Financial impact

The Dubai municipality Al Serkal Envirol Embarked on a journey of excellence under the theme "Recvcle, Re-use, Rethink your waste" meeting the city’s vision and mission in creating a sustainable city, through planning and achieving a balanced set of results for all its stakeholders. The capital cost of the project is about 25 million dhirhams (6 M€).

Clogged sewers result in Sanitary sewer overflows (SSOs) , whereby untreated sewage is discharged to streets, and or sewers back‐up into household residences, or restaurants. SSOs result in considerable clean‐up costs, involve costly damage to sewer infrastructure, result in foul‐smelling odors, can lead to loss of business income, and in extreme situations may cause severe health impacts. The department spends an estimated 2.12 million  dirhams (0,5 M€) annually responding to more than 2,000 grease‐related blockages .

Environmental impact

This project is reducing the flow of fat, oil and grease waste into the sewer system and is improving the public health and safety. Grease trap waste is a contaminated liquid waste and causes a number of problems. Without treatment, the biological and chemical oxygen demand (BOD and COD) of raw grease trap waste wherever it is discharged into the landfill or into the sewer lines or in the deserts will kill plant, aquatic, and animal life. Dumping into landfills allows grease waste to leak into aquifers. It contaminates the ground waters. The practice of sending grease waste to landfill is being reduced now which also results in the reduction of green house gas emissions.

[new] Synergy integration of zinc recovery and sulfate removal in a wastewater stream of viscose fiber production

FACTSHEET

Country: Austria, Wien
Sector: Industry
Loads:  Zinc savings: approx. 3.0 - 3.5 t / d, 70% of input

 

Summary

The best practice comprises the synergy integration of zinc recovery and sulfate/COD removal in a wastewater stream of viscose fiber production. The dissolved zinc reacts with the hydrogren sulphide (H2S) produced by sulfate reducing bacteria in an anaerobic reactor, to zinc sulphide (ZnS). ZnS is then separated from the waterstream by sedimentation, dewatered and further processed to zinc sulfate (ZnSO4). ZnSO4 is reused in the viscose fiber production.

Technology

The process for zinc recovery can be divided into several steps.

1.) Formation of H2S in anaerobic wastewater treatment plant. One part of the wastewater pretreatment is an anaerobic process where sulphate (SO42-) contained in a high strength wastewater stream is reduced to sulphide (S2-) by sulphate reducing bacteria.COD is removed as well by sulphate reduction, relieving the following biological wastewater treatment (activated sludge process).

2.) Precipitation of dissolved zinc. The sulphide formed in the anaerobic step is used to precipitate the zinc (Zn) as zinc sulphide (ZnS). For this purpose a part of the effluent of the anaerobic reactor is pumped backwards and mixed with the Zn-rich wastewater prior entering the anaerobic reactor . As zinc sulphide has a lower solubility than zinc hydroxide, the applied process is advantageous with regard to effluent concentrations (0.01–1ppm level) as compared to the frequent applied zinc precipitation with lime.

3.) Separation of the settled zinc sulphide. After the second step the settled zinc can be dewatered in centrifuges. Afterwards, the dewatered zinc sulphide can be brought to recovery.

4.) Dissolution of zinc sulphide and cleaning the zinc solution. Zinc sulphide is dissolved in a dedicated process with sulphuric acid and can be used again in the viscose production process as zinc sulphate.

Stakeholders

Industry: Lenzing AG

Cooperation with TU-Wien (Vienna University of Technology, Vienna, Austria, Institute for Water Quality, Resources and Waste Management): verification of the applicability of the anaerobic process (sulfate reduction as prerequisite for zinc removal) and assessment of suitable process configuration/ conditions.

Financial impact

The running costs of the zinc recovery process (Process steps 2, 3 and 4) can be covered by the savings of zinc. Pay back of the investment cost is relatively high (>7 years).

Environmental impact

Due to the recycling of zinc Lenzing is able to reuse 70% of the zinc input to the viscose fiber production (3-3.5 t/d), a considerable contribution to natural resource conservation. Considering that primary zinc production has a carbon footprint of 1.5 tons per ton of zinc (Ecoinvent version 3.3, 2016), the reduction in carbon footprint by recycling 3.5 t/d is considerable.

The recovery and reuse of zinc at Lenzing is an important contribution in depleting two major environmental impacts of winning zinc ores: sulfur dioxide (can form acid rain) and cadmium vapor: Through the applied technology Lenzing is able to meet the emission limit values for zinc in the treated effluent wastewater, significantly contributing to water quality protection in the receiving water body. Furthermore, the zinc content in the disposed ash (sewage sludge incineration) is below the required limits.

Additional reference used:

PhD Thesis Vanessa Parravicini, Anaerobe biologische Sulfatentfernung aus Industrieabwässern, 2005, Institute for water Quality, Resources and Waste Management, TU-Wien, Austria

Master Thesis Franz Bauhofer, Biologische Sulfatentfernung aus einem Abwasserstrom der Viskosefaserproduktion, 2003, Institut für Chemische Verfahrenstechnik und Umwelttechnik, TU Granz, Austria

[new] Cellvation: recovery and re-use of cellulose from sewage

FACTSHEET

Country: Netherlands
Sector: Municipal Wastewater
Loads:  When this technology is applied on a large scale in Europe, nearly 5,000 tonnes of dry cellulose per day can be produced.

Summary

Municipal wastewater that is discharged through a sewage system to a wastewater treatment plant (WWTP) contains high quantities of suspended solids, existing for a major part of cellulose that finds its origin in the use of toilet paper. The chain technology, given the catchy name “Cellvation”, consists of a concatenation of innovative processes, designed to produce clean, marketable cellulose feedstock on-site at a WWTP.

The world first Cellvation installation is constructed at the WWTP Geestmerambacht. This installation will, for a period of at least 2 years, differentiate 400 kg/d dry marketable cellulose from sewage. Extraordinary feature of this project is that all recovered cellulose will be used as a raw material in high end products.

Cellvation is a joint development of CirTec (former BWA) B.V. and KNN Cellulose B.V. The recovered resource is cellulose, one of the most important building blocks of the biobased economy. In the EU alone 2.9 billion kilos cellulose can potentially be recovered, corresponding with 100 million trees. As cellulose from toilet paper is of high quality and an excellent raw material for various biodegradable products, it is a waste to not recover this valuable resource.

Technology

Cellvation is a chain technology, consisting of several innovative processes, inspired by mainly the paper- and food industry. It is new and first in its kind, meaning that there is no comparison on best practices. It has been demonstrated, in pilot projects (VAZENA and Zeefgoud) that the technology is working stable, producing a product that can be applied as resource in high-quality products. The VAZENA project included the first application of recovered cellulose in asphalt. Separation of components from the cellulosic sludge takes place mechanically, without the addition of chemicals. Typical steps are sedimentation, flotation, separation, dewatering, pre-drying, pelletizing and post-drying. Sanitation takes place during the drying process.

One step in the Cellvation process is the application of rotating belt finescreens 1), harvesting cellulosic screenings 2). There are now an important number of installations in operation. These finescreens have to be installed in the mainstream waterline. The rest of the process is installed as a side stream treatment and therefore does not affect other processes.

Stakeholders

Works Owner: Hoogheemraadschap Hollands Noorderkwartier Heerhugowaard (The Netherlands)

Location first installation: WWTP Geestmerambacht Warmenhuizen (The Netherlands)

Technology provider: owner and operator of the Cellvation installation: CirTec BV (former BWA) Purmerend (The Netherlands)

We have collaborated with partners in almost the entire chain. With different waterboards as supplier for the cellulosic screenings (feedstock for Cellvation). The EFGF and individual waterboards to align the technology to the future vision of the water boards and to strengthen each other by promoting solving legal issues. With KNN Cellulose as a knowledge carrier between the waterboards and the target markets for cellulose.With all SMART-Plant partners (consortium existing of 9 universities, 7 waterboards and 9 companies) to have the project and the technology embedded into the European frameworks, supported by scientific research. For the project, it is important that it is carried by almost all stakeholders in the value chain. Within the SMART-Plant project, that is supported by a grant from Horizon2020 (Grant Agreement no. 690323), we cooperate on a European scale. Also outside the project, we maintain contact with all concerned, both national and international.

Financial impact

Together with KNN Cellulose BV and Bioclear, a technical feasibility study was conducted with subsequent economic analysis in 2014. Bioclear has expertise on biological contamination and KNN Cellulose is a partner for bringing cellulose to the market. The conclusion of the economic analyses is, that at a scale of 1,000 tonnes of cellulose per year, recovery of marketable cellulose on-site is economically feasible under current market conditions. To make it feasible, a technical depreciation period of 6 years, should be considered.

The value of the recovered cellulose hereby is set at € 120.- per tonne. This amount is lower than the value that can be obtained if the right quality is produced.

Environmental impact

Cellvation closes the value chain for cellulose, while saving energy (less aeration) and chemicals (less polymers for dewatering) that are required for the purification process of sewage. Another substantial benefit of recovering cellulose from wastewater is reduction of waste production (less sludge). Quantitative environmental benefits (on a European scale) are:

  • 15% less sludge(waste) production (annually appr. 3 mln tonnes less sludge is produced)
  • 15% less energy usage (appr. 739 GW/year is saved)
  • 15% less chemicals (appr. 36,000 ton/year on polymers for dewatering is saved)

These benefits also result in a positive business case, ensuring a rapid market uptake and consequent contribution to the biobased/circular economy.

[new] Production of coagulant from iron sludge: successful in manure processing

FACTSHEET

Country: The Netherlands, city of Nieuwegein
Sector: Drinking water sector
Loads: In the Netherlands yearly 50 ktons of iron sludge with a dry matter content of 10% is produced as byproduct of the drinking water industry. The demand for iron sludge by manure plants is a potential of 22.5 kton/a.

Summary

This best practice shows a proven and currently running application of iron sludge (iron(hydr)oxide) from the drinking water industry –after treating with sulfuric acid (also a byproduct, in this case a regeneration acid of the chemical industry.) - as coagulant in the manure processing industry.

Technology

The coagulant is produced onsite at the manure processing plant. Iron sludge is considered in the Netherlands as a product (not waste) and there no extra permits are needed. We’ve learned that the mixing is sensitive to variations in quality of the resources, both chemical as physical. This counts mainly for the iron sludge, that’s why the quality control in intensified and extra sieving step is incorporated to remove macro-pollutants like pine needles. The manure processing plant itself needs 2 extra storage silo’s: one for the iron sludge and one for the sulfuric acid. It also needs a mixing facility.

Stakeholders

The owners of the sludge are the drinking water companies, represented by AquaMinerals

The developer of the coagulant making process is Feralco (not patented)

Manure is either owned by (1) farmers or farmer-cooperatives or (2) professional manure processors.

Financial impact

This process leads to a price for the farmer which lies 10-20% lower. The investment of the manure processing plant (2 silo’s, 1 mixing facility) have a < 1 year payback time.

Environmental impact

An LCA study has led to the conclusion that the impact of the self-made coagulant is 2% of that of the commercially produced coagulant. In other words: 50x better. Important note that this positive impact is for an important part reached by using ‘byproduct’-sulfuric acid.

Furthermore, after the use of this coagulant, the resulting ‘thick manure’ is used as fertilizer. This means that the iron, originating from groundwater, is brought back to the soil where it came from.

Full scale Phosphorus Recovery at WWTP Amsterdam West

FACTSHEET

Country: The Netherlands, Amsterdam
Sector: Sewage water treatment
Loads:  The recovery of phosphorus as struvite leads to a reduction in greenhouse gas  emissions of 1,400 ton CO2-eq/year

Summary

At the wastewater treatment plant (WWTP) Amsterdam West (in total 1.6 million population equivalent) the enhanced biological phosphorus removal lead to massive scaling problems, which occurred after digestion of the primary and secondary sludge. The scaling was identified as struvite. Struvite is a magnesium ammonium phosphate crystal that has commercial value as a fertilizer. During the anaerobic digestion process biologically bound phosphorus is released into the liquid phase and with the present ammonium and magnesium levels struvite formation is very likely. After extensive research, including pilot tests, Waternet concluded that struvite recovery from digested sludge is the best phosphorus removal and recovery technique for this WWTP.   Struvite is a ready to use fertilizer. At WWTP Amsterdam West, approximately 900 ton of struviet are recovered yearly. The product is sold to ICL fertilizers.

Technology

In the fall of 2013 the so called Airprex® technology was implemented at WWTP Amsterdam West, which combines phosphorus removal with phosphorus recovery as struvite. This technology uses the addition of a magnesium salt and elevation of the pH by aeration in order to produce struvite from the digested sludge. After settling, clear crystals of struvite are recovered.

Stakeholders

The struvite installation is owned by the Water authority Amstel, Gooi and Vecht and is operated by Waternet. The struvite installation was built by Eliquo Water & Energy.

The research was carried out in cooperation with other Dutch Water Authorities and STOWA.

Market opportunities and clients for struvite were determined in cooperation with Aqua Minerals, a company that acts as a broker for residuals and wastes of water companies.

An important bottleneck was the legislation on the use of struvite as a fertilizer. The registration in the REACH database, co-signed by Berlin Wasserbetriebe, made it possible to use the struvite as a resource in fertilizer production.

The struvite of WWTP Amsterdam West is sold as a (resource for) fertilizer.

Financial impact

The operational management benefits are approximately €400,000 per year, resulting in a payback time of 10 years.

Environmental impact

The environmental impact of the recovery of phosphorus as  struvite is a reduction in greenhouse gas  emissions of 1,400 ton CO2-eq/year (2.8% of the total greenhouse gas emission of Waternet).

HumVi – humic acids from drinking water production


FACTSHEET

Country Netherlands
Sector Drinking water
Loads 810 m3 of humic acid containing <0.25% salt and 20% humic acids 4.000 m3 of sodiumchloride solution, containing 5% NaCl

 

 

 

Vitens

Three drinking water production plants have ion exchangers to remove organic substances that cause a yellow colour in drinking water. Vitens produces 329,8 million m³ of drinking water yearly (2012). Three production plants use ground water with relatively high concentrations of fulvic/humic acids:

  • Oldeholtpade (6 Mm3/year)
  • Spannenburg (25 Mm3/year)
  • Sint Jansklooster (5 Mm3/year)
  • Since January 2014 the HumVi production plant is running at production location Spannenburg. It recovers humic acid product and sodiumchloride solution.

Technology

  • Ion exchange to remove humic acids from ground water
  • Diafiltration to produce pure humic acid stream
  • Reversed osmosis to produce salt stream that can be reused in ion exchanger

A new installation has been built at location Spannenburg. There were no changes in production location itself; it is an additional process next to main process of producing drinking water.

Stakeholders

The recovered sodiumchloride is implemented for the IEX washing step. The Humic/fulvic acid is used as soil fertilizer in the agricultural sector.

Financial impact

Processing of the waste stream lowered the operational costs to a ROI of 1.5. Time of decision process was 3 months. Building and implementation 1 year. Payback-time was less then 9 months.

Environmental impact

  • 80% reduction of logistics
  • 800 ton CO2 reduction on an annual base

Phosphorus recovery from municipal wastewater

FACTSHEET

Country USA, Oregon
Sector wastewater
Loads Durham TP 1,600 ppd Rock Creek TP 1,500 ppd

 

 

 

Clean Water Services

Clean Water Services (CWS) operates 4 treatment plants, 2 year round and 2 seasonal plants. Both the larger, year round plants have an Ostara nutrient recovery facility. CWS is a consortium of municipalities that combined into one wastewater district that provides holistic wastewater and storm water management.

Technology

Clean Water Services has two Ostara struvite precipitation reactors. The Durham facility also operates a WASSTRIP process to maximize struvite production. A WASTRIP process is being designed for the Rock Creek facility. The WASSTRIP process was invented at our utility and increases the phosphorus released from bio-P sludge which therefore increases the amount of struvite that can be harvested.

The Rock Creek facility is transitioning from chemical phosphorus removal to biological phosphorus removal to improve struvite production.

Stakeholders

Partnering with technology vendor is important, especially when a utility is an early adopter of a technology.

Involve O&M staff early to make the project successful

Consider what instrumentation will be necessary thoroughly.

Financial impact

Since the Durham Ostara facililiity was the first full scale North American installation, the project was very risky. Estimating pay back period was difficult since a market for the product didn’t exist yet. There was also very little full scale operating experience with the technology at that time.

For our Rock Creek Facility, project cost was $4.85 million dollars. We go an energy tax credit of about $1.15 million. The estimated annual revenue from the product was about $690,000 putting the estimated pay back period at around 7 years.

Environmental impact

Not estimated formally. The goal of the clean water grow product is to keep the nutrients within a local community rather than putting a product into a national supply chain with its associated carbon footprint.

Clean Water Grow

Through our agreement with Ostara, Ostara finds end users of the struvite product. Crystal Green (5-28-0 +10% Mg) is a slow release nitrogen, phosphorus and magnesium fertilizer that is used in blends by growers throughout North America. CWS is working on creating our own fertilizer product called Clean Water Grow but this is in the early stages of development.

Shared service center to market residuals


FACTSHEET

Country the Netherlands
Sector Drinking water
Loads 67 kton lime pellets and 68 kton iron sludge

 

 

 

Reststoffenunie

Drinking water sector established RU (Reststoffenunie) as a shared service centre for the sector to ‘market’ the residuals. Combining knowledge, buying- and selling-power and innovation was the main reason to work together. The moment the residuals leave the production site, RU becomes owner of these materials.

Residuals:

  • Iron sludge from ‘de-ironing’ of groundwater
  • Iron sludge from coagulation of suspended solids in surface water
  • Lime pellets from softening of drinking water

Technology

Processes are made in such a way that the residuals are produced as pure as possible and no additives or chemicals are used that have a negative impact on reuse.

Iron sludge: all drinking water companies agreed upon specifications of the sludge as it leaves the production site. These specifications are met by storing and (slightly) passively dewatering the sludge.

Lime pellets are stored in transportation silos easily accessible for trucks.

Stakeholders

Training is given to operators responsible at the production site, giving special attention to quality management. Procedures are available for:

  • Sampling
  • Transportation
  • Analysis

For new productions plants, RU is involved as a consultant looking at the residuals. At current plants, RU takes the initiative for e.g. improvement of the quality of supply chain efficiency.

Combining the residuals from the different drinking water companies was essential, giving the costumer a fair price, good quality and guarantees on the availability.

For the valorization cooperation with SME´s and research companies was important, especially to bring in practical and sometimes theoretical knowledge.

Financial impact

General: waste products are not waste anymore; status from ‘waste’ to ‘byproduct’. The ‘concept’ RU costs the water treatment companies around € 5 per ton as for the shareholder contribution. The sales revenues are exceeding these costs.

Environmental impact

The application of the residuals from the drinking water companies compensates about 15% of their carbon footprint.

Pure calcite pellets


FACTSHEET

Country the Netherlands
Sector Drinking water
Loads 15% of 67 kton softening pellets

 

 

Description

For the softening of drinking water in most cases sand is used as seeding material. This results in softening pellets (diameter about 1,2 mm) consisting of 95% or more CaCO3 and a sand core. The application of these pellets is, because of these two components, more difficult compared to limestone from a quarry. For example the grinding of the pellets is more difficult because of the different harnesses and for a vast number of applications the presence of sand is a no-go (e.g. paper or industrial deacidification).

About 15 %, this number will rise the coming years, of the Dutch softening production is now based upon calcite as seeding material. This results in ‘100% calcite’ pellets, giving more possibilities in high grade applications. The softening with calcite as seeding material is more expensive compared to the traditional softening, but the higher value of the residual more than compensates these costs.

This is not all. The 100% calcite pellets makes it possible for the sector producing their own seeding material, simply by drying, grinding and sieving the pellets. At this moment this is researched under the name ‘Dutch Calcite’, the preliminary results show this is a positive business case.

Technology

Instead of sand calcite will be used as seeding material. This results in 100% pure calcite pellets. No big changes in the softening process are required. The loading of the seeding material in the silo is altered. If the calcite seeding material has too much physical impact, the is a risk the grain distribution is changed. Calcite evidently breaks more easily than sand.

Furthermore, the seeding material can be produced from the calcite pellets by drying, grinding and sieving. In the Netherlands annually 67 kton (metric) softening pellets are produced. At this moment about 15% of this volume is produced with a calcite core. The production of calcite seeding material for the sector is estimated at a maximum of 5 kton.

Stakeholders

Legislation is a hurdle. Reusing raw materials in the drinking water process is something that is not supported by policies or regulations.

Financial impact

The production of pellets with a calcite core is estimated to be 13-17 € more expensive than rationally produced softening pellets. The added value of the pellets in sales revenue is more than these costs.

The seeding material can be produced (estimate, under research) at -25% of the current costs of seeding material.

Investments in the production process are small. A ROI is inapplicable in this case. A drying/grinding/sieving plant has an estimated payback time of 5 years or less.

Main risks are:

  • Hygiene (on the subject of producing ‘own’ seeding material;
  • Market, the sales must transcend costs. Not only now, but also in the future…

Environmental impact

The benefits are:

  • Higher end applications for the pellets, therefore reducing the use of primary chemicals
  • Production of own seeding material, preventing the import of seeding sand from (for example) Australia.

INTEGRAL

This category shows best practices which are cases that show an integrated, holistic approach. e.g. the design of a resource-conserving alternative to conventional centralized infrastructure systems.

[new] Maynilad Carbon Sequestration Program “Plant for Life”

FACTSHEET

Country: The Philippines, Quezon City
Sector: Drinking water production and distribution; domestic-quality wastewater treatment
Loads: 21,287.16 tons of carbon is stocked or captured in the plant biomass and soil. 4,247.91 tons CO2 is sequestered or absorbed from the atmosphere and used for mangrove plant growth.

Summary

Maynilad has been tracking its carbon footprint since 2009 and consistently find that the highest contributor to its carbon emissions are indirect emissions from purchased electricity and fuel ( 90%). This is due to the fact that they have to use energy intensive technologies to produce drinking water. Meanwhile, to offset its carbon emissions, the company developed a carbon sequestration program known as “Plant for Life”. It has two components—watershed rehabilitation and mangrove rehabilitation program.

Technology

The program has two major components—watershed rehabilitation and mangrove rehabilitation program. Maynilad implemented certain changes in its facilities to improve operations and make it more efficient.

Carbon Sequestration is the long-term storage of carbon dioxide or other forms of carbon from the atmosphere and soil biomass. By growing mangroves in coastal areas, Maynilad aims to offset its contribution to global GHG.

Stakeholders

Maynilad Water Services, Inc.

The reforestation and afforestation arm of the project is undertaken with various stakeholders. This is achieved through formal agreements with private organizations and government agencies such as the Department of Environment and Natural Resources; institutionalized participation by partnering with the National Commission on Indigenous People; and leveraging ties with non-profit institutions and other volunteer organizations

Financial impact

Estimated expenditure of mangrove rehabilitation since 2013 is Php 420,000. Some US$538 worth of fish can be produced from Philippine mangroves per hectare/year

Environmental impact

Plant for Life. 21,287.16 tons of carbon is stocked or captured in the plant biomass and soil instead of being released to the atmosphere as CO2. 4,247.91 tons CO2 is sequestered or absorbed from the atmosphere and used for mangrove plant growth instead of contributing to the global GHG. These figures will continue to rise as the mangroves grow through the years.

[new] OMZET Amersfoort: waste water treatment as energy and mineral recovery utility

FACTSHEET

Country: The Netherlands, city of Amersfoort
Sector: Municipal wastewater
Loads:  60% increase in biogas production, export of 1.7 GWh/year excess power. 115 tonnes/year of phosphorus and 45 tonnes/year of nitrogen in the form of a high value commercial fertilizer.

Summary

The project addresses the municipal wastewater treatment sector with an innovative technology configuration aimed to increase the energy self-sufficiency of the process and recover phosphate, while maintaining high effluent quality.  The result was the successful establishment of an Energy and Nutrient Recovery Factory at Vallei en Veluwe’s Amersfoort STP.

Technology

Combination of LysoTherm®) technology; Pearl® and WASSTRIP® technologies.

The new installation was commissioned at the end of 2015, starting with the LysoTherm TPH, followed by the Pearl reactor in February 2016 treating dewatering centrate only. Additional sludge imports and WASSTRIP operations began in April 2016.

The WASSTRIP reactor at Amersfoort STP receives over 7,200 tonnes per year of indigenous primary sludge and surplus activated sludge (SAS) as well as over 4,200 tonnes per year of imported SAS from surrounding WWTPs. In the WASSTRIP process, SAS is held anaerobically which causes phosphorus accumulating organisms (PAOs) to release stored phosphorus.  Following phosphorus release, the SAS is thickened and the liquors are diverted to Pearl. In Pearl, the phosphorus rich thickening liquors are combined with ammonia rich dewatering liquors from digested sludge and magnesium to precipitate nutrients in the form of struvite (magnesium ammonium phosphate hexahydrate).  Once struvite particles have grown to the desired size in the reactor they are harvested, dewatered and dried.  The particles are classified according to size and bagged ready for sale as Crystal Green® fertiliser.

Stakeholders

Amersfoort STP is owned and operated by Waterschap Vallei en Veluwe and serves a population equivalent of approximately 300,000 in the Utrecht province of the Netherlands.

In 2010, The project was delivered by ELIQUO WATER & ENERGY, who delivered a combination of their own proprietary technologies (including LysoTherm®) and third party technologies including Ostara Nutrient Recovery Solutions’ Pearl® and WASSTRIP® technologies.

Financial impact

It is expected that the €11 mln initial investment will be recovered in 7 years.  Benefits are comprised of a combination of revenue from power exports and fertilizer, and operational cost savings (notably power, sludge disposal and chemicals).

Environmental impact

The project will minimize carbon emissions though a combination of:

  • Up to 60% increase in biogas production, resulting in energy neutrality of the WWTP and export of 1.7 GWh/year excess power;
  • Recover up to 115 tonnes/year of phosphorus and 45 tonnes/year of nitrogen in the form of a high value commercial fertiliser;
  • Reduce sludge production by 17%;
  • Reducing chemical (ferric and alum) dosing for phosphorus removal;
  • Maintaining high effluent quality.

The Crystal Green fertiliser produced at Amersfoort offers good properties due to the mode of action – Crystal Green is not water soluble therefore reducing phosphorus tie-up in soils and run-off into water bodies where it causes eutrophication.

[new] Water and Energy Independent WWTP through Positive Impact Development technique for Recovering Small Water Cycle

FACTSHEET

Country: South Korea, Anyang City, Gyeonggi Province about 30 km south of Seoul
Sector: Sewage water treatment ( 250,000 ㎥/day for 1,257,256 population)
Loads: Total saving of 25,610.5 tCO2/year of total greenhouse gas. 10% of the 200,000 ㎥ of daily sewage treatment capacity is reused to save water.

Summary

Korea's sewage treatment plant, Anyang Saemul Park has secured its self-sufficiency through the recovery of water and energy resources. This case shows the transformation of a sewage treatment plant from the one where energy was consumed and water was released to the one that produces energy and collects the water resources. By reaffirming the value of the rainwater and sewage that flow into the sewage treatment plant, the sewage treatment plant was improved so that it could reduce the supply of external water and energy resources, and thus restored the water and energy resources to the level of self-reliance. The purpose of this case study at Anyang is to explain the technology that can restore the resources, show its appropriateness, and to re-establish the meaning of resource recovery as the role model in this area through the philosophical interpretation of the technology.

Technology

Positive Impact Development (PID technology) as development role model pursues development through restoring resources while positively affecting the environment.

Water Recovery Part

Combined with the advantages of the A2O method and the SBR method, the CSBR method was applied to maximize the processing performance.  YDF (Fiber Disk Filter) was applied to the tertiary (total phosphorus) treatment process to minimize eutrophication of discharge stream. Biofiltration and ozone treatment facilities were selected to provide T-N and chromaticity processing capability and to internally supply water that meet the re-used water quality standards. In addition, rainwater was used after being treated simply by physical precipitation and UV disinfection.

Energy Recovery Part

In order to maximize the production of energy during sewage sludge treatment, anaerobic digestion technology developed by POSCO E&C and certified by the Ministry of Environment as new technology, and integral fixed-bed drying technology were applied. In the anaerobic digestion process, THP (with high solubilization rate due to cell membrane breakdown of excess residue) and anaerobic single-phase digester were applied.

Stakeholders

  • POSCO Engineering and Construction (technology provider)
  • Anyang City (owner)
  • Korea Environment Corporation K-eco (operator)

Financial impact

The benefit is estimated at a total of 10 million dollar/year, combined with other energy waste heat recovery and energy costs saved from renewable energy, including sales of power and supply certificate sales (4.5 million dollar/year) through digestion gas generation. Cost and benefit analysis shows that the payback time is about 12 years, which is considered to be economical.

Environmental impact

The plant  is operating at a 70% energy independence rate based on energy production of 10,308 TOE/year (14,831 TOE/year of energy consumption), which represents a replacement effect of 98.5 billion KRW (76 M€) of fossil fuel for 20 years. In addition, rainwater and sewage reclaimed water recovered to water resources, replace more than 90% of 20,000 tons/day of water used for operation management inside and outside the sewage treatment plant, saving a total of about 7,200,000 tons/year of water resources and about 4 million dollar per year of water costs.

Billund BioRefinery – Resource Recovery for the Future

FACTSHEET

Country: Denmark, Billund
Sector: Sewage water treatment
Loads:  5.000 tons Biofertilizer cake (25% DS) and 3,0 million Nm3 Biogas annually

Summary

In the Danish wastewater sector energy consumption is addressed (savings and production) and also recovery of phosphorous. Energy production is based on digestion, and in the specific case in Billund Biorefinery it is codigestion of WW sludge and organic waste from households and industries (local).The key idea is to produce more refined products out of wastewater and organic waste – i.e. biofertilizer, Struvite (or even purer), biogas (and possibility of upgrading) and biopolymer. The biorefinery is an "open concept" that can collect all types of waste, including wastewater and convert them into valuable resources. Thus, there are obvious opportunities to assemble the entire circuit of carbon and nutrients from farm to table and back to land.

Technology

Billund Biorefinery is a prototype of the biorefinery concept and includes several technologies at different stages of development. Of particular notice is one of the two first AnitaMox facilities in Denmark, the first full-scale installation of EXELYS ™ in the world and the prototype for online control of the biogas digesters. Also Magnesium as precipitating agent, in order to create a more refined fertilizer product , is an area of development in the project.

The heart of the refinery is the DLD(Digestion-Hydrolysis-Digestion) process with EXELYS™ (thermal hydrolysis), so that the amount of remaining biofertilizer is minimized and the yield of CO2-neutral biogas is maximized.

Following elements/processes are part of the Biorefinery:

  • Optimized aeration for nitrification
  • Anammox proces for Reject water from digesters
  • Struvite production
  • Biopolymer production
  • Polishing of effluent/CSOs
  • Reuse of treated Wastewater
  • Advanced online control of Bio P removal (STAR)
  • Advanced online control of maximized biogas production (STAR for mix of wastewater sludge/waste and digester control)

Input:  Input 950 ton DS sludge/y, 1.750 ton DS organic Household Waste/y and 2.450 ton DS organic Industry waste/y

Output:

5.000 tons Biofertilizer cake/y (25% DS). The biofertilizer contains 6 P kg /ton and 11 kg N/ton.

3,0 mio Nm3 Biogas/y = 6,8 GWh Electricity/y and 3.6 GWh Excess Heat/y (only heat for the district heating)

Stakeholders

Billund Municipality is the owner. The Plant is run by Billund Water A/S.

Technology provider is Veolia and its subsidiaries Krüger, AnoxKaldnes and Hydrotech.

Financial impact

Cash flows are generated from: Inlet of Wastewater (tax approx +5,5€/m3); Output of treated Wastewater (- tax on m3 and contents of N,P and BI5 ); Input of organic wastes (+ 33€ pr ton (average ) and Open for all types; Output of bio fertilizer (- 26,6 €/ton); Output of electricity (+140 €/Mwh); Output of heat (6,67 €/Mwh); Future sales of refined P (+estimated 330 €/ton); Future sales of biopolymer (+not estimated).

Total payback time is estimated to be under 10 years without recovering of Struvite and biopolymer.

Environmental impact

By rebuilding the wastewater treatment plant for biorefinery Billund Water achieves increased capacity for the treatment of wastewater and waste, while the company's CO2 footprint for all activities is CO2 positive. Billund Water also achieves a significant operating savings and new opportunities for finding more new partners from agriculture, municipalities (food waste), as well as the opportunity to reduce wastewater- and waste charges for customers.

Sorting of household organic waste at the consumer level has spread to other municipalities in Denmark through the examples of collection and usage demonstrated by Billund BioRefinery, and Denmark is closing up on the EU strategy saying 60% reuse of all wastes.

Semizentral


FACTSHEET

Country People's Republic China, Qingdao
Sector Integrated water, energy and food
Size 12,000 people equivalent

 

 

 

Semizentral

The characteristic of SEMIZENTRAL is its integrated approach. Conventional systems focus on the strict separation of water supply, wastewater treatment, and waste treatment. In contrast, SEMIZENTRAL integrates these sectors into a holistic approach. It enables the coordination between the sectors, creating synergy effects such as energy self-sufficient operation and the reduction of greenhouse gases.

Compared to conventional infrastructure systems, the benefits are the potential for 30-40% or more reduction in water use, no external energy demand for wastewater and waste treatment, greatly reduced transport demand, around-the-clock water supply with consistent quality, and high planning security. The same applies to wastewater and waste.

Technologies

  • Greywater treatment: mechanical pretreatment, MBR (Membrane bio-reactor), chemical disinfection (chlorine, required by Chinese standards))
  • Blackwater treatment: mechanical pretreatment, MBR (Membrane bio-reactor), chemical disinfection (chlorine)
  • Sludge and foodwaste treatment: pretreatment of foodwaste (separation of nuisance substances/disinfection), thermophilic digestion, Biogas à power and heat via CHP
  • Technology provider: “standard technologies” provided by several Chinese and German companies

Stakeholders

Non potable water is reused in households. As the buildings are new, owners of apartments where not involved yet in the planning stage;
The investor (operator of the World Horticulture Exposition – WHE) was involved in the planning and influenced the water reuse purposes (using irrigation water for irrigation at the WHE)
Electric power is “clean” (carbon footprint); no quality constrains are expected; feed in the grid is still in discussion.

Driver for the City of Qingdao was the embedded energy in the water cycle. Nearby water reuse is compared to desalination much more energy efficient (< 1kWh/m³ compared to 3 to 4 kWh/m³).

Financial

Cost benefit analysis has to be done.

Risks and dependencies

  • Challenge of (missing) acceptance of water reuse within households
  • Higher Capex (but lower power demand as well as lower capex and opex for sewer because of nearby treatment)
  • Challenge of (missing) acceptance of separate biowaste collection within households, which was first intended
  • Competition with alternative (partly illegal) disposal systems for sewage sludge and foodwaste

Environmental impact

Environmental impact assessment according to Shandong/Chinese requirements had to be done. GHG reduction and social aspects will be evaluated within the next 2 years.

MBR in the water cycle and thermophilic instead of mesophilic digestion to enhance quality of biosolids.

Bottlenecks

Subsidization of water and wastewater make it difficult to implement water saving technologies and systems. Convincing was the lower embedded energy in the water cycle – SEMIZENTRAL is much more energy efficient as alternative water resources e.g. desalination. This is an incentive independent of the cost for water and energy cost

First implementation without full-scale reference makes a) the technological and b) the financial feasibility more challenging

Dealing with much more authorities (water supply, sanitation, solid waste, hygienic department, energy suppliers) compared to non-integrated approaches are a challenge.

Shared service center to market residuals


FACTSHEET

Country the Netherlands
Sector Drinking water
Loads 67 kton lime pellets and 68 kton iron sludge

 

 

 

Reststoffenunie

Drinking water sector established RU (Reststoffenunie) as a shared service centre for the sector to ‘market’ the residuals. Combining knowledge, buying- and selling-power and innovation was the main reason to work together. The moment the residuals leave the production site, RU becomes owner of these materials.

Residuals:

  • Iron sludge from ‘de-ironing’ of groundwater
  • Iron sludge from coagulation of suspended solids in surface water
  • Lime pellets from softening of drinking water

Technology

Processes are made in such a way that the residuals are produced as pure as possible and no additives or chemicals are used that have a negative impact on reuse.

Iron sludge: all drinking water companies agreed upon specifications of the sludge as it leaves the production site. These specifications are met by storing and (slightly) passively dewatering the sludge.

Lime pellets are stored in transportation silos easily accessible for trucks.

Stakeholders

Training is given to operators responsible at the production site, giving special attention to quality management. Procedures are available for:

  • Sampling
  • Transportation
  • Analysis

For new productions plants, RU is involved as a consultant looking at the residuals. At current plants, RU takes the initiative for e.g. improvement of the quality of supply chain efficiency.

Combining the residuals from the different drinking water companies was essential, giving the costumer a fair price, good quality and guarantees on the availability.

For the valorization cooperation with SME´s and research companies was important, especially to bring in practical and sometimes theoretical knowledge.

Financial impact

General: waste products are not waste anymore; status from ‘waste’ to ‘byproduct’. The ‘concept’ RU costs the water treatment companies around € 5 per ton as for the shareholder contribution. The sales revenues are exceeding these costs.

Environmental impact

The application of the residuals from the drinking water companies compensates about 15% of their carbon footprint.