Ключевые слова: above, aerial, big, biology, biomass, circle, city, clean, construction, dirty, down, drone, drones, ecology, effluent, environment, factory, farm, flow, fly, green, hong, industrial, industry, kong, over, plant, poland, pollution, purification, purified, purity, recycle, recycling, sewage, sha tin, storage, tank, technology, top, top down, treatment, urban, view, waste, wastewater, water, works,