Wastes originate from all stages of leather making process, such as fine leather particles, residues from various chemical discharges and reagents from different waste liquors comprising of large pieces of leather cuttings, trimmings and gross shavings, fleshing residues, solid hair debris and remnants of paper bags.
Tanning refers to the process by which collagen fibers in a hide react with a chemical agent (tannin, alum or other chemicals). However, the term leather tanning also commonly refers to the entire leather-making process. Hides and skins have the ability to absorb tannic acid and other chemical substances that prevent them from decaying, make them resistant to wetting, and keep them supple and durable. The flesh side of the hide or skin is much thicker and softer. The three types of hides and skins most often used in leather manufacture are from cattle, sheep, and pigs.
Out of 1000 kg of raw hide, nearly 850 kg is generated as solid wastes in leather processing. Only 150 Kg of the raw material is converted in to leather. A typical tannery generate huge amount of waste:
Chrome shaving, chrome splits and buffing dust: 35-40%
Skin trimming: 5-7%
Over 80 per cent of the organic pollution load in BOD terms emanates from the beamhouse (pre-tanning); much of this comes from degraded hide/skin and hair matter. During the tanning process at least 300 kg of chemicals (lime, salt etc.) are added per ton of hides. Excess of non-used salts will appear in the wastewater.
Because of the changing pH, these compounds can precipitate and contribute to the amount of solid waste or suspended solids. Every tanning process step, with the exception of finishing operations, produces wastewater. An average of 35 m3 is produced per ton of raw hide. The wastewater is made up of high concentration of salts, chromium, ammonia, dye and solvent chemicals etc.
A large amount of waste generated by tanneries is discharged in natural water bodies directly or indirectly through two open drains without any treatment. The water in the low lying areas in developing countries, like India and Bangladesh, is polluted in such a degree that it has become unsuitable for public uses. In summer when the rate of decomposition of the waste is higher, serious air pollution is caused in residential areas by producing intolerable obnoxious odours.
Tannery wastewater and solid wastes often find their way into surface water, where toxins are carried downstream and contaminate water used for bathing, cooking, swimming, and irrigation. Chromium waste can also seep into the soil and contaminate groundwater systems that provide drinking water for nearby communities. In addition, contamination in water can build up in aquatic animals, which are a common source of food.
Lead-acid batteries (also known as LABs) are a common item in our daily lives. Once the lead of the battery is timed out, we have no option but to dump it because it has no use for us anymore, but the copper plates in the battery remain reusable which can be used for recycling. There are some disagreements about the benefits of recycling battery, say alkaline battery, over simple disposal because the mercury in the battery no longer exists and the disposal material is abundant and non-toxic. But for automotive batteries the scenario is different in terms of benefits. The recycling of this type of battery holds both economic and environmental benefits.
The reusable material from the used battery is removed and recycled which reduces the needs for raw materials which is originally imported from abroad. It creates a balance payment and cost. In addition to this there can be considerable environmental impact during mining processes such as emission from smelting of sulfide ore, copper, nickel, and cobalt and this can be eliminated if recycling can be introduced.
Dangers of Lead-Acid Batteries
LABs generally consist of both sulphuric acid and large amount of lead which is not only corrosive but also a good carrier for soluble lead and lead particles. Lead is highly toxic metal which causes a wide range of adverse health effect especially on young children. If one gets expose excessively to lead it can cause damage to brain and kidney, impair hearing, and can led to various other associated problems. On an average an automobile manufactured contain about 12kg of lead, in which about 96% of lead is used in lead acid battery and remaining 4% is used in other applications like wheel balance weight, protective coating and variation dampers.
Both lead and cadmium are harmful for human health and environment. This toxic substances seeps into the soil, groundwater and surface water through landfill and also releases toxins into the air when they are burnt in municipal waste incinerators. Moreover cadmium can be easily absorbed by the pant root and get into the fruits, vegetables, and waters are consumed by animals and human beings, they can fall to prey to a host of ill effects.
Studies have shown that nausea, excessive salivation, abdominal pain, liver and kidney damage, skin irritation, headaches, asthma, nervousness, decreased IQ in children, and sometimes even cancer can result from exposure to such metals for a sufficient period of time.
Need for Effective Control Measures
In a battery recycling plant, effective control measures need to be implemented, both to protect the health of workers and to prevent pollution of the environment. Good plant design, with reduction of the potential for the emission of contaminating substances is of utmost importance and the newer smelting processes are inherently much cleaner than traditional blast furnaces.
Pollution abatement technologies, including the treatment of exhaust gases and liquid effluents, need to be installed. Those mostly exposed to releases within the plants are the workforce. Control measures such as maintaining minimum standards of air quality within the works, medical surveillance of employees, use of protective equipment, and provision of conditions of good hygiene in general, is necessary to avoid occupational lead exposure. However, few government/non-governmental steps have been taken yet; rather this practice is a traditional trading system as prevail in the society.
Positive and Negative Impacts
In developing countries such as Bangladesh, recycling or reusing of used lead-acid batteries has both positive and negative impact on environment. Positive impact is that, if battery is recycled in proper and in sustainable manner it saves environment from toxic material of battery, otherwise battery waste is dumped into the landfills. Negative impact is that if recycling is not done in sustainable manner emits gases produced from battery recycling has adverse impacts on environment and human being.
In a battery recycling plant, effective control measures are required to safeguard public health and environment.
Direct recycling process should be banned as it has adverse impact on environment. As it is an illegal process, shopkeepers perform this process in hidden way. Government should impose the law and regulation strictly in this occurrence. This information can be used for advertising material highlighting the environmental benefits of recycling or reusing encourages the purchasing of old lead acid battery. It will accelerate the selling rate of old battery.
Importance of Awareness
Necessary steps should be taken to increase awareness about environmental impacts of used lead acid batteries. Proper instruction should be provided among the general mass. It will also increase reusing of old battery. Battery regeneration is a unique process specially designed to revive the lost capacity of batteries and give priority to choose secondary battery. Battery Reuse Centre can be developed for effective reuse and recycle.
The aim to divert reusable battery, donated by the public, which often could have been destined for landfill and instead provides a much needed source of low-cost battery to those in need. The battery reuse service encourages volunteer involvement and trainee placements in all aspects of its operation. Awareness program (posters, pamphlets, TV & radio commercials, road-shows, website, exhibitions, talks), infrastructure, information center, tax rebates for manufacturers should be taken to increase recycling or reusing of old battery.
Solid waste management is already a significant concern for municipal governments across South Asia. It constitutes one of their largest costs and the problem is growing year on year as urban populations swell. As with all waste management experiences, we have learned lessons and can see scope for improvement.
Collection and Transportation
There are two factors which have a significant impact on the costs and viability of a waste management system as it relates to collection and transportation: first, the distance travelled between collection and disposal point; and second, the extent to which ‘wet’ kitchen waste can be kept separate from dry waste much of which can be recycled. Separating waste in this way reduces the costs of manual sorting later on, and increases the prices for recyclable materials.
In many larger towns distances become too great for door-to-door collectors to dispose waste directly at the dump site. Arrangements are made to dispose of waste at secondary storage points (large skips) provided by the municipality. However, where these are not regularly emptied, the waste is likely to be spread beyond the bins, creating a further environmental hazard.
Ideally, and if suitable land can be found, a number of smaller waste disposal sites located around a town would eliminate this problem. With significant public awareness efforts on our part, and continual daily reminders to home-owners, we were able to raise the rate of household separation to about 60%, but once these reminders became less frequent, the rate dropped rapidly back to around 25%. The problem is compounded in larger cities by the unavailability of separated secondary storage bins, so everything is mixed up again at this point anyway, despite the best efforts of householders.
If rates are to be sustained, it requires continual and on-going promotion in the long term. The cost of this has to be weighed against the financial benefit of cleaner separated waste and reduced sorting costs. Our experience in Sri Lanka shows how important a role the Local Authority can play in continuing to promote good solid waste management practices at the household level.
Our experience with home composting shows that complete coverage, with every household using the system, is very unlikely to be achieved. Where we have promoted it heavily and in co-operation with the Local Authority we have found the sustained use of about 65% of the bins. Even this level of coverage, however, can have an important impact on waste volumes needing to be collected and disposed of. At the same time it can provide important, organic inputs to home gardening, providing a more varied and nutritious diet for poor householders.
Waste to Compost and Waste to Energy
The variety of technologies we have demonstrated have different advantages and disadvantages. For some, maintenance is more complicated and there can be issues of clogging. For the dry-fermentation chambers, there is a need for a regular supply of fresh waste that has not already decomposed. For other systems requiring water, quite large amounts may be needed. All of these technical challenges can be overcome with good operation and maintenance practices, but need to be factored in when choosing the appropriate technology for a given location.
The major challenge for compost production has been to secure regular sales. The market for compost is seasonal, and this creates an irregular cash flow that needs to be factored in to the business model. In Bangladesh, a significant barrier has been the need for the product to be officially licensed. The requirements for product quality are exacting in order to ensure farmers are buying a product they can trust.
However, the need for on-site testing facilities may be too prescriptive, creating a barrier for smaller-scale operations of this sort. Possibly a second tier of license could be created for compost from waste which would allow sales more easily but with lower levels of guarantees for farmers.
Safe Food Production and Consumption
Community people highly welcomed the concept of safe food using organic waste generated compost. In Sri Lanka, women been practicing vertical gardening which meeting the daily consumption needs became source of extra income for the family.
Female organic fertilizer entrepreneurs in Bangladesh are growing seasonal vegetables and fruits with compost and harvesting more quality products. They sell these products with higher price in local and regional markets as this is still a niche market in the country. The safe food producers require financial and regulatory support from the government and relevant agencies on certification and quality control to raise and sustain market demand.
The concept of safe food using organic waste generated compost is picking up in South Asia
Solid waste management is an area that has not received the attention it deserves from policy-makers in South Asia nations. There are signs this may change, with its inclusion in the SDGs and in many INDCs which are the basis of the Paris Climate Agreement. If we are to meet the challenge, we will need new approaches to partnerships, and the adoption of different kinds of systems and technologies. This will require greater awareness and capacity building at the Local Authority level. If national climate or SDG targets are to be met, they will need to be localised through municipalities. Greater knowledge sharing at national and regional levels through municipal associations, regional bodies such as SAARC and regional local authority associations such as Citynet, will be an important part of this.
Practical Action’s key messages for regional and national policy makers, based on our experience in the region in the last 5 years, are about the need for:
creating new partnerships for waste collection with NGOs and the informal sector,
considering more decentralised approaches to processing and treatment, and
recognising the exciting potential for viable technologies for generating more value from waste
Waste management systems can be divided into a number of steps from collection, storage, transportation, processing, treatment, recycling and final disposal. Integrated solid waste management refers to this entire process and aims to maximise resource use efficiency, with minimal amounts ending up in final disposal sites. During Practical Action’s recent work in the South Asia region, we have gained particular experiences in terms of firstly waste collection, storage and transportation; and secondly waste processing in particular of organic waste.
Collection and Transportation
In many cities, waste collection services fail to reach all areas of the town or city. People are left to manage their own waste, which they do by burning and burying it, or dumping on open spaces. Sometimes large bins or skips are provided but they may be irregularly emptied, and also overflow when the contents is picked over by waste pickers and animals.
In Bangladesh, in order to help increase the overall capacity for collecting household waste, Practical Action has promoted a door-to-door collection service run by local NGOs. Residents pay a service charge in addition to their municipal rates, but in return they receive a regular service, leading to a cleaner neighbourhood.
In Faridpur, the local NGO, WORD, with technical backstopping from Practical Action serves more than 5,000 customers with waste collection. There are three main types of customer, non-slum households, slum households and institutions. Slum-based households are charged the lowest tariffs (minimum BDT 10) while the institutional rate is highest (minimum BDT 150).
The numbers of slum households is small because the alternative option of localized composting (with a barrel system) was widely taken up. This is easier than collection through vans and is useful for slum people as they can use the compost later. Waste collectors use small rickshaw vans for the collection service. Recently we have also introduced small small rickshaw vans and small motorized versions for the collection service.
The waste is taken to a composting facility where it is sorted and the organic portion is separated for composting, and in some cases for generating biogas. In 2008, WORD started the waste collection business with only 525 customers. In the last 8 years, the number has increased more than tenfold (5,100 customer per month) making the solid waste management a viable business. It has not only contributed to a better living environment, but also generated green and dignified jobs for 21 waste workers.
The municipal conservancy department continues to play a regulatory and coordinating role through the Waste Management Steering Committee. This meets regularly to discuss any emerging issues and review the progress of door-to-door collection services. The conservancy department continues to manage the sweeping of streets and drains, and collection of waste from some areas of the town, from vegetable markets and slaughter houses. The only recycling and reuse of organic waste is done by WORD, as all municipal waste for now continues to be disposed at an open dumping site where no further treatment, sorting or reuse takes place.
In Nepal, Practical Action has facilitated organic waste management under a public-private partnership model. For example, in Butwal Municipality, a private firm, Marry Gold Concern, collects and manages wastes from 400 households with a monthly service fee of NPR 50 (GBP 0.33) in an area called Ramnagar. The company employs three operators for collecting and managing waste from low income communities. A compost plant has been set up which processes up to 10 metric tonnes of organic waste and generate 5 metric tonnes of compost per month. In addition, recyclable waste, mainly plastic, is sold to scrap dealers, creating another source of income.
Recycling and Disposal by Forming Associations and Enterprises
In Bangladesh, collection services have been organised through existing local NGOs. In Nepal, Practical Action has instead helped to form different groups of Informal Waste Workers (IWW) such as street waste pickers, waste segregators, pheriya (dry waste pickers), scrap owners and door to door collectors.
We have worked intensively with IWW from five municipalities of Kathmandu Valley. We have facilitated the establishment of a IWWs association called Samyukta Safai Jagaran (SASAJA), and the first waste workers’ cooperative with the same name. These organisations have distributed identity cards to members to increase their recognition as an ‘official’ part of the waste management system. We provided basic safety equipment to 5,622 IWWs, including rain boots/shoes, gloves, masks, raincoats, windcheaters with trouser and wrapper, aprons, cap etc. to minimize health risks.
Basic safety equipment is essential to minimize health risks to informal recycling sector.
Following capacity building and skill enhancement training from Practical Action, many of the IWW group members have established waste-based enterprises. For example, plastic tearing (PET bottle and carton crushing or pressing) for recycling and reuse; paper recycling and mechanical composting of organic waste. This approach has been scaled up in other municipalities in Chitwan and Rupadehi districts reaching around 350 IWWs there.
Reducing Waste through Home Composting
In Nepal and Sri Lanka, and in some slum communities in Bangladesh, we have promoted barrel composting of organic waste. This has the dual benefit of producing compost locally which can be used for home gardening, and reducing the amount of waste that needs to be collected and disposed of elsewhere.
It can reduce the amount of organic waste coming in to the waste collection stream by about 20-30%. It requires community involvement in waste management system as well as frequent monitoring and troubleshooting. This process ensures source segregation of waste, a necessary condition for proper implementation of the 3R system (reuse, reduce and recycle).
Practical Action has distributed more than 2,000 compost bins in Sri Lanka. Especially in Galle, Kurunegala and Akkaraipattu cities where we have distributed about 1,500 home composting bins from 2006 to 2016. More than 65% of the bins are being regularly used.
Our experience shows that once a locality is provided with home composting, the volume of organic waste into the municipal collection system is reduced around 20-30%. However, this varies greatly by locations. If the local authority strictly monitors the compost bin usage and provides troubleshooting support, waste reduction can reach up to 30%.
Both Kurunegala and Galle municipal councils have upscaled the distribution of bins city-wide with the support of national government funding. This technology was taken up by the private sector and other municipal councils. It has been used widely in the country as a solution for reducing organic waste coming in to the waste collection system. For example, Kandy municipal council has adopted the technology with strict restriction on organic waste collection in the municipality collection system.
The Provincial Agriculture department in Kurunegala and the Coconut cultivation board in Akkaraipattu are both promoting organic agriculture with the usage of composting and are using Practical Action’s work as examples for expansion. The central government has provided seeds and fertilizer to city dwellers, including the urban poor, to promote home gardening.
This has been further expanded by Kurunegala municipal council which has distributed potted plants. Some of the vertical gardening structures promoted by Practical Action are now included in urban gardening models of the Western Province Urban Agriculture unit.
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