As India’s summer intensifies,many states are already in the midst of a drought—and the hottest days have yet to arrive. At the same time, water-intensive agriculture, rapid urban expansion, increases in industrial activity and growing energy production are driving the country’s water demand upward.More than half of India is now considered severely water stressed.

Part of the problem is that India still manages its water as an infinite resource on a linear model of withdrawal, consumption and disposal. But a more efficient management model is to look at water from a“circular economy” perspective. Water’s usability doesn’t need to end once it washes down the drain. Rather, we can see industrial and domestic wastewater as a valuable resource from which usable water, nutrients and even renewable energy can be extracted.

Reusing Wastewater through Sludge-to-Energy Plants

如下所示，大多数城镇的废水处理设施都是基本的。Vittal Boggaram/Wri的照片
如下所示，大多数城镇的废水处理设施都是基本的。Vittal Boggaram/Wri的照片

污泥到能源系统can make the dream of a circular economy a reality by turning waste into an input, instead of just an output. These systems can be developed asindependent, decentralized unitsthat require minimal outside energy for operations. From raw sewage, they generate three useful products: energy, digestate and water that can be reused for agriculture, industry and even domestic uses such as watering gardens and flushing toilets.

它的工作原理：废水处理厂首先将污水分离为固体“污泥”和液态水。然后，这种富含甲烷的污泥经历了两个过程：溶解水解和厌氧消化 - 以快速有效地去除病原体和线束沼气。然后，所得的沼气可以用作现场能量，以供应废水处理厂，也可以进一步净化并作为天然气出售。此外，厌氧消化后剩下的固体消化物可用于增强土壤。（但是，消化物中某些重金属的存在可能使其不适合土地应用。）

工厂的财务需求和运营商的技术能力可以告知选择哪种污泥技术和系统，并且可以安装在现有的废水处理厂中，从而减少了对新基础设施的需求。这节省了时间，空间和金钱。

A Win-Win for India

污泥到能源系统can also help in another way. India’s urban populations have grown so drastically that sewage treatment systems cannot keep up with the amount of human waste being generated.There are only enough treatment systems in India to treat 37 percent of the country’s sewage—and that’s if they were all operating at maximum capacity. In reality, even less than 37 percent of sewage is probably treated—the rest is often dumped in waterways or on land. Untreated sewage contains large concentrations of pathogens and other contaminants that can make people sick.

尽管有新兴的政策处理城市卫生设施，但由于诸如高安装和维护成本，运行此类单位所需的大量能量以及对训练有素的技术人员的需求，传统的废水处理设施的吸收有限。此外，传统设施需要在印度已经密集的城市地区大量额外的空间。非传统，较小的污泥到能源系统可以通过出售天然气和消化收入以及使用沼气来满足现场能源需求来克服这些障碍。污泥到能源系统can help wastewater treatment become financially feasible, provide renewable energy and reduce greenhouse gas emissions—all while helping to meet India’s growing water and sanitation needs.

Implementing Sludge-to-Energy Systems in India

WRI India is currently leading research on the potential for implementing sludge-to-energy systems in Indian cities.过去的WRI研究发现中国西亚阳的污泥到能源系统将产生相当大的经济，环境和社会益处 - 印度的城市也可以这样说吗？我们在印度的研究将绘制水和废水领域的政策和机构景观，考虑哪些设计和方法符合印度的需求，并确定这种系统增加对水压力的弹性的潜力。通过利用废水的资源，印度城市可能能够同时获得清洁的水，能源和改善的卫生能力。