Decentralized Wastewater Treatment, Puducherry, and Japan’s Johkasou

Two weeks ago we published an article describing the open sewage systems in Puducherry, a Union territory in South India. In these systems, wastewater from businesses and homes is simply released into the environment with little to no treatment. This release poses a threat to public health and local water quality.

The conventional method of wastewater treatment requires a network of pipes and sewer lines that feed into a centralized wastewater treatment plant. After treatment, the water is expelled to a nearby body of water or used as reclaimed water. The conventional method often requires a central authority (e.g. a city government) to organize construction of sewer lines and connect users to the public system. After that, the authority must ensure that the treatment plant continues to operate correctly.

It is challenging to build and maintain a functioning wastewater treatment plant. In the United States we often take the operation of wastewater treatment plants for granted –the US has a strong regulatory system which ensures that municipalities and governments keep their services running as promised. In countries with less accountability in government (a consequence of corruption, holes in public policy, civil unrest, economic problems, a weak judicial system, etc.), centralized disposal systems are difficult to implement successfully. In Ghana, for instance, many wastewater treatment plants are constructed and then abandoned after just a few years of operation.

One alternative to utilizing a centrally controlled conventional treatments system is utilizing a decentralized array of smaller treatment systems. According to Small & Decentralized Wastewater Management Systems, decentralized wastewater management may be defined as the collection, disposal, or reuse of wastewater from individual homes, clusters of homes, isolated communities, or parts of existing communities at or near the point of wastewater generation. By having an array of decentralized treatment systems, regions are less susceptible to a total failure of wastewater treatment. The failure of one centralized system will stop treatment on a large scale. The failure of one decentralized system will only affect a small group of people.

Japan’s Miniature Wastewater Treatment Plants: Johkasou

The Puducherry Pollution Control Committee has decided to adopt a solid waste management scheme similar to Japan’s model. In the realm of wastewater treatment, the PPCC should also consider one of Japan’s approaches to decentralized wastewater treatment: the “johkasou.”

A johkasou is a wastewater treatment tank. It looks like a septic tank, but it behaves like a miniature wastewater treatment plant. The technology that engineers have fit into these small tanks is impressive –a small-scale johkasou for an individual house might sport an anaerobic filter tank, contact aeration tank, sedimentation tank, and disinfection tank. All of these treatment tanks can be held in a main tank as small as 4 cubic meters, and once water undergoes johkasou treatment it can be used for non-potable applications or released directly to the environment.

According to the Japan Sanitation Consortium, johkasou require electric energy comparable to the energy needed to light a room (a system designed for 5 people will consume about 37 kWh per month –the same amount of energy consumed by a 60 W lightbulb kept on for 26 days straight). Johkasou are intended for areas with limited access to centralized sewage systems. Because the tanks require electricity to operate, they cannot be used in areas that lack reliable electricity supply.

Installing a johkasou typically requires one week of construction work. The cost to purchase and install a 5-person johkasou is about ¥860,000, or nearly $10,000. Depending on the region, the Japanese government has subsidized between 40% to 90% of this cost for homeowners and businesses interested in having a johkasou.

Why would the Japanese government subsidize up to 90% the cost for a small-scale system? Release of untreated wastewater into the environment can threaten the fishing industry and increase water treatment costs downstream. Also, threats to public health increase healthcare expenditures and can hinder productivity (sick people are less productive). The economic benefits of decentralized wastewater treatment coupled with a cultural desire to protect Japan’s environment make it appealing for the government to subsidize johkasou programs.

Is a conventional wastewater treatment system feasible in Puducherry? In 2007, only about 30% of the urban area had sewage service. The other 70% discharged wastewater to the environment via exposed channels or septic tanks.

The costs associated with the conventional system and the johkasou decentralized systems are high. One must study the Puducherry hydrology, its political climate, its economic system, and its culture before a decision can be made. Centralized systems? Or decentralized systems? Or both?

In 2005, 35 million people in Japan (about 27% of the country’s population) used johkasou tanks. The technology is widely used, and it may offer regions like Puducherry a way to clean its wastewater without centralized treatment systems. Other cheaper alternatives to the johkasou include natural treatment systems like treatment wetlands and ponds. Unlike a johkasou, however, a natural treatment system often requires more land area than highly urbanized areas can provide.

To learn more about johkasou use in Japan, visit the Japan Education Center of Environmental Sanitation website here.

Tags: Japan, johkasou, Puducherry, wastewater
Posted in Waste Management, Water Treatment | 1 Comment »

Bangalore Lakes in Grave Need of Help!

The last stop in my trip to India was Bangalore. Bangalore is the third largest city in India. Bangalore is known as the Silicon Valley of India, due to the rampant IT industry there. It is one of the most prominent cultural and economic hubs in India. Bangalore is truly a beautiful city. However, it is notorious for three things: traffic, frequent power outages, and severe water scarcity.

Let’s talk water – Almost all of the city’s water supply comes from the Cauvery and the Arkavathy Rivers. The Bangalore Water Supply and Sewerage Board (BWSSB) supplies approximately 900 million liters of water daily. However, the demand of water exceeds 1.2 billion liters. Many people once relied on the lakes to suffice their water needs. Most of the lakes of Bangalore are man-made, constructed for the purposes of drinking water, irrigation and fishing. Currently, the lakes in Bangalore suffer heavy amounts of pollution. The Greater Bangalore region once had 400 lakes. Now there are only around 93.

One lake that has suffered greatly from pollution is the Bellandur Lake. The Bellandur Lake is located in East Bangalore and spans an area of 960 acres.  The Lake was once used a main source of water for the people of Bangalore. Water was used for irrigation, fishing, and for household matters, including drinking, washing, and cleaning. Until the 1970s, people in 18 different villages depended on the Bellandur Lake for their everyday needs. The lake has been greatly affected by the rapid urbanization that has been occurring in Bangalore. It has been negatively impacted by domestic and industrial pollution, the destruction of wetlands and the changes in the land usage surrounding the lake. Unplanned urbanization along with unchecked industrial, domestic, and commercial development caused the lake started to suffer greatly.

Currently, a large portion of the lake is covered in weeds and fields. The water in the lake is greatly polluted. There is no aquatic life within the lake. The stench emanating from the lake is beyond foul. At the outlet of the lake, heavy foam from an excess of industrial effluent can be seen.

The Bellandur Lake is connected to the Agara Lake through a stormwater drain. Bangalore consists of a series of interconnected lakes. The Agara and Madivalla connect to the Bellandur Lake. The outlet of the Bellandur connects to the Varthur.  The lakes are connected by an extensive stormwater drainage system. The system once carried water, however, now it carries sewage. The Bellandur Lake is located in one of the three main valleys of Bangalore, known as the Koramangala and Challagatha Valley. Due to its location, the lake has been used to direct a large portion of Bangalore’s sewage. Currently, the BWSSB has set up three sewage treatment plants with a total capacity of 248 MLD. However, only 110 MLD of the total capacity is actually utilized.  According to the BWSSB, by 2021, the volume of sewage produced by the city will be 359 MLD; by 2036, the volume will be 416 MLD. Already, urbanization and the flux of sewage into the lake have led to eutrophication. An increase in the volume of sewage will only lead to the lake’s further demise.

A major problem exists within the stormwater drains. There is so much pollution within these drains. Untreated domestic waste and industrial effluents are dumped straight into them. The pollution in the drains is directly transferred into the lakes. The pictures below show the pollution accumulating within these drains.

The lakes were once able to serve as natural wetlands, treating the wastewater that flowed into them from the stormwater drains. However, the amount of pollution in these drains exceeds the remediation capabilities of the lakes. The main problem exists in the lack of a strictly enforced waste disposal policy. Punishments should be given to those who are polluting the stormwater drains and the lakes. The citizens of Bangalore should be made aware of the amount of pollution entering the drains and also educated on proper waste disposal techniques, including recycling. Industries polluting the lakes should be fined heavily. Also, the BWSSB should work to increase the capabilities of their treatment plants.

There are various government bodies that are responsible for the Bellandur Lake, including: the Bruhat Bangalore Mahanagara Palike (BBMP), the BWSSB, the Minor Irrigations Department (MID), and the Lake Development Authority (LDA). The lake is located in the jurisdiction of the BBMP. The BBMP is the civic corporation that governs Bangalore. It is responsible for the maintenance of the storm water drains that lead into the lake. The BWSSB is responsible for properly regulating the sewage that enters the lake. The MID has ownership of the lake. The LDA is entrusted with maintaining and preserving the lakes in Bangalore.  These organizations should work together to help preserve the lakes and stormwater drains.

There have been many pleas and enquiries to the government of the Bangalore to help remediate this situation. However, no substantial progress has been made. A strong commitment to restoring the Bellandur Lake and cleaning the stormwater drains must be taken.

Tags: Bangalore, IT industry, scarcity, stormwater drains
Posted in Development, India, Pollution, Waste Management, Water management, Water Resources, Wetlands | No Comments »

Open Sewage Systems Hinder Development in Puducherry

It’s been two weeks since I have arrived in India. Although I have spent most of my time in Chennai, I have had the opportunity to travel to several other parts of South India. Recently I visited Puducherry (formerly known as Pondicherry), a Union territory of India. Puducherry is one of the most popular tourist destinations in South India. It was under French rule until 1954. The city still retains much of the French influence – the entire layout of the city was planned to imitate French design, mainly in the grid pattern of the city. Colonial ambience of the city is still preserved. Puducherry contains many colonial buildings, temples, churches, historical monuments, and beautiful beaches. Most of the city has been well maintained and remains quite picturesque.

Unfortunately, the beauty of the city was immediately contrasted by the sight and the smell of the open sewage system that exists throughout the city. I was shocked to see that a city with such well developed infrastructure lacked a proper sewage system. The following photos show the open sewage system that runs throughout the city

An open sewage system raises many environmental and public health issues. Sewage containing human wastes is the most dangerous material polluting the water. The main diseases transmitted through the polluted water are typhoid, paratyphoid, dysentery, and infective hepatitis. Canals containing waste water in Puducherry mix with various bodies of water. In a point where the waste water mixes with sea water, the total coliform count was found to be 475 and the fecal coliform count was found to be 130. This is indicative of fecal contamination creating a high risk of disease. This dire problem can be attributed to the lack of proper waste water treatment.

During the monsoon season or other periods of heavy rain, the sewage system often floods. Currently, flooding is experienced more frequently due to an increase of garbage clogging and overburdening the sewage system. The clogging of the drains creates conditions ideal for disease vectors to breed. During times of flooding, diseases such as malaria, dengue fever, filaria, viral fever, and brain fever are reported. In a place called Solai Nagar in Puducherry all of the sewage is directed into one canal. This canal has not been desilted in years. An excess of waste has clogged the canal, leaving sewage to stagnate in the roadside drains. The drains inevitably overflow during periods of rain. Reports of untreated waste from a nearby hospital polluting the drains have also been filed. Obviously the open sewage system is a pressing issue. Something must be done immediately to expedite the implementation of a proper sewage system within Puducherry.

The Puducherry Pollution Control Committee (PPCC) has devised a scheme to install an underground drainage system and proper waste water treatment facilities in Puducherry. The models are designed to mimic the Japanese solid waste management system. Currently none of the waste in Puducherry is treated, whereas in Japan, 100% of the waste is treated. There is a 70-80% municipal recycling rate in most parts of Japan. Japan has taken a firm stance on minimizing the amount of waste produced in the nation, in addition to maximizing recycling throughout. The current policy in Japan emphasizes an incineration/waste-to-energy plan as a main means of disposing of municipal solid waste. The citizens of Japan are educated on the benefits of recycling and proper waste disposal from a very young age. Almost everyone in the nation is committed to and enthusiastic about keeping Japan clean.

The amount of waste generated annually in Puducherry is projected to increase greatly by 2020. The PPCC has adopted a four pronged plan to most effectively implement the drainage system. The first phase of this plan consists of planning and organizing along with institution building. During this phase, the PPCC wishes to enhance the collection and transport of waste. The next phase consists of the expansion of the service area. In this phase, plans for the control and the protection from pollution of the dump site are included. The third phase consists of introducing the 3-R’s (reduce, reuse, recycle). In addition, social partnerships will be considered and developed. The fourth, and final stage of the PPCC’s plan consists of the total integration of the 3-R’s. In addition, further efforts to educate the citizens on a recycle-oriented and sustainable society, such as the one in Japan, will be made.

Unplanned development of Puducherry has created many environmental problems. These problems have ultimately lowered the standard of living in the city. Amenities that we consider basic, such as clean drinking water, proper drainage facilities for waste, and adequate sewage treatment facilities, are either scarce or non-existent there. There has been a great deal of environmental stress on Puducherry, including increased pollution and the loss of biodiversity. In addition, public health has been risked since there is an improper sewage system. Hopefully the government of Puducherry takes a strong commitment to implementing a closed drainage system. In order for Puducherry to continue to expand and further develop, proper waste treatment must be invested in. It is sad to see such a beautiful city be burdened by the lack of proper sewage infrastructure. Hopefully the Japanese model will serve to help Puducherry reach its full potential as a growing city.

Tags: Open Sewage, Puducherry
Posted in Design, India, Pollution, Waste Management, Water management | 2 Comments »